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Luo G, Zhu T, Ren Z. METTL3 Regulated the Meat Quality of Rex Rabbits by Controlling PCK2 Expression via a YTHDF2–N6-Methyladenosine Axis. Foods 2022; 11:foods11111549. [PMID: 35681299 PMCID: PMC9180525 DOI: 10.3390/foods11111549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/10/2022] [Accepted: 05/15/2022] [Indexed: 01/27/2023] Open
Abstract
N6-methyladenosine (m6A) is the most prevalent internal mRNA modification in eukaryotes. The M6A modification plays an important role in transcription and cell function. The mechanism by which m6A modification regulates meat quality remains elusive. In this study, gene knockout and overexpression were used to explore m6A-modified regulation of meat quality. The content of PCK2 in blood increased significantly with the increase of Rex rabbits’ age. PCK2 expression levels in the longissimus lumborum and liver also increased significantly with the increase of Rex rabbits’ age. However, the expression level of PCK2 showed no significant difference in adipose tissue. In cell experiments, we found that METTL3 inhibited adipocyte differentiation by targeting the PCK2 gene via the recognition function of YTHDF2. Finally, the results of correlation analysis showed that PCK2 expression was positively correlated with intramuscular fat, whereas PCK2 expression was negatively correlated with total water loss rate at three different stages. In addition, PCK2 expression was also negatively correlated with reduced pH value at 75 and 165 days. Intramuscular fat content, pH and muscle water holding capacity are the main factors affecting the taste and flavor of muscle. Therefore, N6-methyladenosine regulated muscle quality by targeting the PCK2 gene.
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2
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Li Y, Pollock CA, Saad S. Aberrant DNA Methylation Mediates the Transgenerational Risk of Metabolic and Chronic Disease Due to Maternal Obesity and Overnutrition. Genes (Basel) 2021; 12:genes12111653. [PMID: 34828259 PMCID: PMC8624316 DOI: 10.3390/genes12111653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/02/2021] [Accepted: 10/17/2021] [Indexed: 12/13/2022] Open
Abstract
Maternal obesity is a rapidly evolving universal epidemic leading to acute and long-term medical and obstetric health issues, including increased maternal risks of gestational diabetes, hypertension and pre-eclampsia, and the future risks for offspring's predisposition to metabolic diseases. Epigenetic modification, in particular DNA methylation, represents a mechanism whereby environmental effects impact on the phenotypic expression of human disease. Maternal obesity or overnutrition contributes to the alterations in DNA methylation during early life which, through fetal programming, can predispose the offspring to many metabolic and chronic diseases, such as non-alcoholic fatty liver disease, obesity, diabetes, and chronic kidney disease. This review aims to summarize findings from human and animal studies, which support the role of maternal obesity in fetal programing and the potential benefit of altering DNA methylation to limit maternal obesity related disease in the offspring.
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Affiliation(s)
- Yan Li
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610072, China;
| | - Carol A. Pollock
- Kolling Institute of Medical Research, University of Sydney, Sydney, NSW 2065, Australia;
| | - Sonia Saad
- Kolling Institute of Medical Research, University of Sydney, Sydney, NSW 2065, Australia;
- Correspondence:
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3
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Davis MA, Camacho LE, Pendleton AL, Antolic AT, Luna-Ramirez RI, Kelly AC, Steffens NR, Anderson MJ, Limesand SW. Augmented glucose production is not contingent on high catecholamines in fetal sheep with IUGR. J Endocrinol 2021; 249:195-207. [PMID: 33994373 PMCID: PMC8175032 DOI: 10.1530/joe-21-0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 04/22/2021] [Indexed: 01/04/2023]
Abstract
Fetuses with intrauterine growth restriction (IUGR) have high concentrations of catecholamines, which lowers the insulin secretion and glucose uptake. Here, we studied the effect of hypercatecholaminemia on glucose metabolism in sheep fetuses with placental insufficiency-induced IUGR. Norepinephrine concentrations are elevated throughout late gestation in IUGR fetuses but not in IUGR fetuses with a bilateral adrenal demedullation (IAD) at 0.65 of gestation. Euglycemic (EC) and hyperinsulinemic-euglycemic (HEC) clamps were performed in control, intact-IUGR, and IAD fetuses at 0.87 of gestation. Compared to controls, basal oxygen, glucose, and insulin concentrations were lower in IUGR groups. Norepinephrine concentrations were five-fold higher in IUGR fetuses than in IAD fetuses. During the EC, rates of glucose entry (GER, umbilical + exogenous), glucose utilization (GUR), and glucose oxidation (GOR) were greater in IUGR groups than in controls. In IUGR and IAD fetuses with euglycemia and euinsulinemia, glucose production rates (GPR) remained elevated. During the HEC, GER and GOR were not different among groups. In IUGR and IAD fetuses, GURs were 40% greater than in controls, which paralleled the sustained GPR despite hyperinsulinemia. Glucose-stimulated insulin concentrations were augmented in IAD fetuses compared to IUGR fetuses. Fetal weights were not different between IUGR groups but were less than controls. Regardless of norepinephrine concentrations, IUGR fetuses not only develop greater peripheral insulin sensitivity for glucose utilization but also develop hepatic insulin resistance because GPR was maintained and unaffected by euglycemia or hyperinsulinemia. These findings show that adaptation in glucose metabolism of IUGR fetuses are independent of catecholamines, which implicate that hypoxemia and hypoglycemia cause the metabolic responses.
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Affiliation(s)
- Melissa A Davis
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Leticia E Camacho
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Alexander L Pendleton
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Andrew T Antolic
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Rosa I Luna-Ramirez
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Amy C Kelly
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Nathan R Steffens
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Miranda J Anderson
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
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4
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Jones AK, Rozance PJ, Brown LD, Goldstrohm DA, Hay WW, Limesand SW, Wesolowski SR. Sustained hypoxemia in late gestation potentiates hepatic gluconeogenic gene expression but does not activate glucose production in the ovine fetus. Am J Physiol Endocrinol Metab 2019; 317:E1-E10. [PMID: 30964701 PMCID: PMC6732654 DOI: 10.1152/ajpendo.00069.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 02/08/2023]
Abstract
Fetal hypoxemia is associated with pregnancy conditions that cause an early activation of fetal glucose production. However, the independent role of hypoxemia to activate this pathway is not well understood. We hypothesized that fetal hypoxemia would activate fetal glucose production by decreasing umbilical glucose uptake and increasing counter-regulatory hormone concentrations. We induced hypoxemia for 9 days with maternal tracheal N2 gas insufflation to reduce maternal and fetal arterial Po2 by ~20% (HOX) compared with fetuses from ewes receiving intratracheal compressed air (CON). At 0.9 of gestation, fetal metabolic studies were performed (n = 7 CON, 11 HOX). Umbilical blood flow rates, net fetal oxygen and glucose uptake rates, and fetal arterial plasma glucose concentrations were not different between the two groups. Fetal glucose utilization rates were lower in HOX versus CON fetuses but not different from umbilical glucose uptake rates, demonstrating the absence of endogenous glucose production. In liver tissue, mRNA expression of gluconeogenic genes G6PC (P < 0.01) and PCK1 (P = 0.06) were six- and threefold greater in HOX fetuses versus CON fetuses. Increased fetal norepinephrine and cortisol concentrations and hepatic G6PC and PCK1 expression were inversely related to fetal arterial Po2. These findings support a role for fetal hypoxemia to act with counter-regulatory hormones to potentiate fetal hepatic gluconeogenic gene expression. However, in the absence of decreased net fetal glucose uptake rates and plasma glucose concentrations, hypoxemia-induced gluconeogenic gene activation is not sufficient to activate fetal glucose production.
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Affiliation(s)
- Amanda K Jones
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Paul J Rozance
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Laura D Brown
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - David A Goldstrohm
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - William W Hay
- Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, University of Arizona , Tucson, Arizona
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5
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Pulsatile hyperglycemia increases insulin secretion but not pancreatic β-cell mass in intrauterine growth-restricted fetal sheep. J Dev Orig Health Dis 2018; 9:492-499. [PMID: 29973299 DOI: 10.1017/s2040174418000417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Impaired β-cell development and insulin secretion are characteristic of intrauterine growth-restricted (IUGR) fetuses. In normally grown late gestation fetal sheep pancreatic β-cell numbers and insulin secretion are increased by 7-10 days of pulsatile hyperglycemia (PHG). Our objective was to determine if IUGR fetal sheep β-cell numbers and insulin secretion could also be increased by PHG or if IUGR fetal β-cells do not have the capacity to respond to PHG. Following chronic placental insufficiency producing IUGR in twin gestation pregnancies (n=7), fetuses were administered a PHG infusion, consisting of 60 min, high rate, pulsed infusions of dextrose three times a day with an additional continuous, low-rate infusion of dextrose to prevent a decrease in glucose concentrations between the pulses or a control saline infusion. PHG fetuses were compared with their twin IUGR fetus, which received a saline infusion for 7 days. The pulsed glucose infusion increased fetal arterial glucose concentrations an average of 83% during the infusion. Following the 7-day infusion, a square-wave fetal hyperglycemic clamp was performed in both groups to measure insulin secretion. The rate of increase in fetal insulin concentrations during the first 20 min of a square-wave hyperglycemic clamp was 44% faster in the PHG fetuses compared with saline fetuses (P0.23). Chronic PHG increases early phase insulin secretion in response to acute hyperglycemia, indicating that IUGR fetal β-cells are functionally responsive to chronic PHG.
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6
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Soo JY, Wiese MD, Berry MJ, McMillen IC, Morrison JL. Intrauterine growth restriction may reduce hepatic drug metabolism in the early neonatal period. Pharmacol Res 2018; 134:68-78. [PMID: 29890254 DOI: 10.1016/j.phrs.2018.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/23/2018] [Accepted: 06/04/2018] [Indexed: 11/26/2022]
Abstract
The effects of intrauterine growth restriction (IUGR) extend well into postnatal life. IUGR is associated with an increased risk of adverse health outcomes, which often leads to greater medication usage. Many medications require hepatic metabolism for activation or clearance, but hepatic function may be altered in IUGR fetuses. Using a sheep model of IUGR, we determined the impact of IUGR on hepatic drug metabolism and drug transporter expression, both important mediators of fetal drug exposure, in late gestation and in neonatal life. In the late gestation fetus, IUGR decreased the gene expression of uptake drug transporter OATPC and increased P-glycoprotein protein expression in the liver, but there was no change in the activity of the drug metabolising enzymes CYP3A4 or CYP2D6. In contrast, at 3 weeks of age, CYP3A4 activity was reduced in the livers of lambs born with low birth weight (LBW), indicating that LBW results in changes to drug metabolising capacity in neonatal life. Together, these results suggest that IUGR may reduce hepatic drug metabolism in fetal and neonatal life through different mechanisms.
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Affiliation(s)
- Jia Yin Soo
- Early Origins of Adult Health Research Group, Adelaide, SA, 5001, Australia; School of Pharmacy & Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, 5001, Australia
| | - Michael D Wiese
- School of Pharmacy & Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, 5001, Australia
| | - Mary J Berry
- Centre for Translational Physiology, Wellington, New Zealand; Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | | | - Janna L Morrison
- Early Origins of Adult Health Research Group, Adelaide, SA, 5001, Australia; School of Pharmacy & Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, SA, 5001, Australia.
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7
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Hwang JH, An SM, Kwon S, Park DH, Kim TW, Kang DG, Yu GE, Kim IS, Park HC, Ha J, Kim CW. DNA methylation patterns and gene expression associated with litter size in Berkshire pig placenta. PLoS One 2017; 12:e0184539. [PMID: 28880934 PMCID: PMC5589248 DOI: 10.1371/journal.pone.0184539] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 08/26/2017] [Indexed: 11/18/2022] Open
Abstract
Increasing litter size is of great interest to the pig industry. DNA methylation is an important epigenetic modification that regulates gene expression, resulting in livestock phenotypes such as disease resistance, milk production, and reproduction. We classified Berkshire pigs into two groups according to litter size and estimated breeding value: smaller (SLG) and larger (LLG) litter size groups. Genome-wide DNA methylation and gene expression were analyzed using placenta genomic DNA and RNA to identify differentially methylated regions (DMRs) and differentially expressed genes (DEGs) associated with litter size. The methylation levels of CpG dinucleotides in different genomic regions were noticeably different between the groups, while global methylation pattern was similar, and excluding intergenic regions they were found the most frequently in gene body regions. Next, we analyzed RNA-Seq data to identify DEGs between the SLG and LLG groups. A total of 1591 DEGs were identified: 567 were downregulated and 1024 were upregulated in LLG compared to SLG. To identify genes that simultaneously exhibited changes in DNA methylation and mRNA expression, we integrated and analyzed the data from bisulfite-Seq and RNA-Seq. Nine DEGs positioned in DMRs were found. The expression of only three of these genes (PRKG2, CLCA4, and PCK1) was verified by RT-qPCR. Furthermore, we observed the same methylation patterns in blood samples as in the placental tissues by PCR-based methylation analysis. Together, these results provide useful data regarding potential epigenetic markers for selecting hyperprolific sows.
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Affiliation(s)
- Jung Hye Hwang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Sang Mi An
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Seulgi Kwon
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Da Hye Park
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Tae Wan Kim
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Deok Gyeong Kang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Go Eun Yu
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | - Il-Suk Kim
- Department of Animal Resource Technology, Gyeongnam National University of Science & Technology, Jinju, South Korea
| | | | - Jeongim Ha
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
- * E-mail: (JH); (CWK)
| | - Chul Wook Kim
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju, South Korea
- * E-mail: (JH); (CWK)
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8
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Wesolowski SR, Hay WW. Role of placental insufficiency and intrauterine growth restriction on the activation of fetal hepatic glucose production. Mol Cell Endocrinol 2016; 435:61-68. [PMID: 26723529 PMCID: PMC4921201 DOI: 10.1016/j.mce.2015.12.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023]
Abstract
Glucose is the major fuel for fetal oxidative metabolism. A positive maternal-fetal glucose gradient drives glucose across the placenta and is sufficient to meet the demands of the fetus, eliminating the need for endogenous hepatic glucose production (HGP). However, fetuses with intrauterine growth restriction (IUGR) from pregnancies complicated by placental insufficiency have an early activation of HGP. Furthermore, this activated HGP is resistant to suppression by insulin. Here, we present the data demonstrating the activation of HGP in animal models, mostly fetal sheep, and human pregnancies with IUGR. We also discuss potential mechanisms and pathways that may produce and support HGP and hepatic insulin resistance in IUGR fetuses.
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Affiliation(s)
- Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA
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9
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A review of fundamental principles for animal models of DOHaD research: an Australian perspective. J Dev Orig Health Dis 2016; 7:449-472. [DOI: 10.1017/s2040174416000477] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Epidemiology formed the basis of ‘the Barker hypothesis’, the concept of ‘developmental programming’ and today’s discipline of the Developmental Origins of Health and Disease (DOHaD). Animal experimentation provided proof of the underlying concepts, and continues to generate knowledge of underlying mechanisms. Interventions in humans, based on DOHaD principles, will be informed by experiments in animals. As knowledge in this discipline has accumulated, from studies of humans and other animals, the complexity of interactions between genome, environment and epigenetics, has been revealed. The vast nature of programming stimuli and breadth of effects is becoming known. As a result of our accumulating knowledge we now appreciate the impact of many variables that contribute to programmed outcomes. To guide further animal research in this field, the Australia and New Zealand DOHaD society (ANZ DOHaD) Animals Models of DOHaD Research Working Group convened at the 2nd Annual ANZ DOHaD Congress in Melbourne, Australia in April 2015. This review summarizes the contributions of animal research to the understanding of DOHaD, and makes recommendations for the design and conduct of animal experiments to maximize relevance, reproducibility and translation of knowledge into improving health and well-being.
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10
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Culpepper C, Wesolowski SR, Benjamin J, Bruce JL, Brown LD, Jonker SS, Wilkening RB, Hay WW, Rozance PJ. Chronic anemic hypoxemia increases plasma glucagon and hepatic PCK1 mRNA in late-gestation fetal sheep. Am J Physiol Regul Integr Comp Physiol 2016; 311:R200-8. [PMID: 27170658 DOI: 10.1152/ajpregu.00037.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/08/2016] [Indexed: 01/30/2023]
Abstract
Hepatic glucose production (HGP) normally begins just prior to birth. Prolonged fetal hypoglycemia, intrauterine growth restriction, and acute hypoxemia produce an early activation of fetal HGP. To test the hypothesis that prolonged hypoxemia increases factors which regulate HGP, studies were performed in fetuses that were bled to anemic conditions (anemic: n = 11) for 8.9 ± 0.4 days and compared with control fetuses (n = 7). Fetal arterial hematocrit and oxygen content were 32% and 50% lower, respectively, in anemic vs. controls (P < 0.005). Arterial plasma glucose was 15% higher in the anemic group (P < 0.05). Hepatic mRNA expression of phosphonenolpyruvate carboxykinase (PCK1) was twofold higher in the anemic group (P < 0.05). Arterial plasma glucagon concentrations were 70% higher in anemic fetuses compared with controls (P < 0.05), and they were positively associated with hepatic PCK1 mRNA expression (P < 0.05). Arterial plasma cortisol concentrations increased 90% in the anemic fetuses (P < 0.05), but fetal cortisol concentrations were not correlated with hepatic PCK1 mRNA expression. Hepatic glycogen content was 30% lower in anemic vs. control fetuses (P < 0.05) and was inversely correlated with fetal arterial plasma glucagon concentrations. In isolated primary fetal sheep hepatocytes, incubation in low oxygen (3%) increased PCK1 mRNA threefold compared with incubation in normal oxygen (21%). Together, these results demonstrate that glucagon and PCK1 may potentiate fetal HGP during chronic fetal anemic hypoxemia.
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Affiliation(s)
- Christine Culpepper
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Center for Women's Health Research, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Joshua Benjamin
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Jennifer L Bruce
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Center for Women's Health Research, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Sonnet S Jonker
- Knight Cardiovascular Institute Center for Developmental Health, Oregon Health & Science University, Portland, Oregon
| | - Randall B Wilkening
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Center for Women's Health Research, University of Colorado School of Medicine, Aurora, Colorado; and
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11
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Lie S, Morrison JL, Williams-Wyss O, Suter CM, Humphreys DT, Ozanne SE, Zhang S, MacLaughlin SM, Kleemann DO, Walker SK, Roberts CT, McMillen IC. Impact of maternal undernutrition around the time of conception on factors regulating hepatic lipid metabolism and microRNAs in singleton and twin fetuses. Am J Physiol Endocrinol Metab 2016; 310:E148-59. [PMID: 26487010 PMCID: PMC4719029 DOI: 10.1152/ajpendo.00600.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 08/31/2015] [Indexed: 01/11/2023]
Abstract
We have investigated the effects of embryo number and maternal undernutrition imposed either around the time of conception or before implantation on hepatic lipid metabolism in the sheep fetus. We have demonstrated that periconceptional undernutrition and preimplantation undernutrition each resulted in decreased hepatic fatty acid β-oxidation regulators, PGC-1α (P < 0.05), PDK2 (P < 0.01), and PDK4 (P < 0.01) mRNA expression in singleton and twin fetuses at 135-138 days gestation. In singletons, there was also lower hepatic PDK4 (P < 0.01), CPT-1 (P < 0.01), and PKCζ (P < 0.01) protein abundance in the PCUN and PIUN groups and a lower protein abundance of PDPK-1 (P < 0.05) in the PCUN group. Interestingly, in twins, the hepatic protein abundance of p-AMPK (Ser(485)) (P < 0.01), p-PDPK-1 (Ser(41)) (P < 0.05), and PKCζ (P < 0.05) was higher in the PCUN and PIUN groups, and hepatic PDK4 (P < 0.001) and CPT-1 (P < 0.05) protein abundance was also higher in the PIUN twin fetus. We also found that the expression of a number of microRNAs was altered in response to PCUN or PIUN and that there is evidence that these changes may underlie the changes in the protein abundance of key regulators of hepatic fatty acid β-oxidation in the PCUN and PIUN groups. Therefore, embryo number and the timing of maternal undernutrition in early pregnancy have a differential impact on hepatic microRNA expression and on the factors that regulate hepatic fatty acid oxidation and lipid synthesis.
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Affiliation(s)
- Shervi Lie
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Janna L Morrison
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Olivia Williams-Wyss
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia; Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Catherine M Suter
- Victor Chang Cardiac Research Institute, Darlinghurst, Australia; Faculty of Medicine, University of New South Wales, Kensington, Australia
| | | | - Susan E Ozanne
- University of Cambridge, Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Song Zhang
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Severence M MacLaughlin
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - David O Kleemann
- South Australian Research and Development Institute, Turretfield Research Centre, Rosedale, Australia
| | - Simon K Walker
- South Australian Research and Development Institute, Turretfield Research Centre, Rosedale, Australia
| | - Claire T Roberts
- Institute and School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia; and
| | - I Caroline McMillen
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia; The Chancellery, University of Newcastle, Newcastle, Australia
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12
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Wei S, Li W, Yu Y, Yao F, A L, Lan X, Guan F, Zhang M, Chen L. Ginsenoside Compound K suppresses the hepatic gluconeogenesis via activating adenosine-5′monophosphate kinase: A study in vitro and in vivo. Life Sci 2015; 139:8-15. [DOI: 10.1016/j.lfs.2015.07.032] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 07/27/2015] [Accepted: 07/29/2015] [Indexed: 02/04/2023]
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13
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Field ME, Anthony RV, Engle TE, Archibeque SL, Keisler DH, Han H. Duration of maternal undernutrition differentially alters fetal growth and hormone concentrations. Domest Anim Endocrinol 2015; 51:1-7. [PMID: 25460066 DOI: 10.1016/j.domaniend.2014.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 09/12/2014] [Accepted: 09/12/2014] [Indexed: 01/12/2023]
Abstract
To investigate the impact of duration of maternal undernutrition in twin sheep pregnancies, ewes were either fed 100% (C) or 50% of their nutrient requirements from 28 to 78 d gestational age (dGA) and readjusted to 100% beginning at 79 dGA (LC) or continuously restricted from 28 to 135 dGA (LL). Weights of the fetus, empty carcass, brain, and liver were greater in the LC than LL fetuses at 135 dGA (P ≤ 0.05). Although umbilical vein (UmV) glucose concentrations did not differ, the UmV:umbilical artery (UmA) glucose gradient was smaller (0.26 ± 0.03 vs 0.38 ± 0.03 and 0.39 ± 0.04 mmol L(-1); P ≤ 0.05) in LL than C and LC fetuses, respectively. Umbilical vein concentrations of IGF-1 were less (46.7 ± 5.62 vs 74.3 ± 6.71 ng/mL; P ≤ 0.05) in LL than LC fetuses. Additionally, LL fetuses tended (P ≤ 0.10) to have lower UmA concentrations of insulin (0.24 ± 0.13 vs 0.70 ± 0.15 ng/mL) and IGF-1 (66.6 ± 7.51 vs 91.4 ± 8.97 ng/mL) than LC fetuses. Although most of the observed differences occurred between LC and LL pregnancies, LC fetuses tended (P ≤ 0.10) to have greater UmV and UmA pCO2 than C fetuses. Furthermore, the UmV:UmA O2 content gradient tended to be greater (5.02 ± 0.43 vs 3.41 ± 0.47; P ≤ 0.10) in C than LL fetuses. UmA placental lactogen also tended to be greater (46.6 ± 4.40 vs 31.1 ± 4.69 ng/mL; P ≤ 0.10) in LL than C fetuses. These data suggest that in twin pregnancies, maternal undernutrition followed by realimentation induces a different fetal outcome compared with continuous nutrient restriction, and both may differ physiologically from control fed pregnancies.
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Affiliation(s)
- M E Field
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - R V Anthony
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - T E Engle
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - S L Archibeque
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - D H Keisler
- Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA
| | - H Han
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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Houin SS, Rozance PJ, Brown LD, Hay WW, Wilkening RB, Thorn SR. Coordinated changes in hepatic amino acid metabolism and endocrine signals support hepatic glucose production during fetal hypoglycemia. Am J Physiol Endocrinol Metab 2015; 308:E306-14. [PMID: 25516551 PMCID: PMC4329495 DOI: 10.1152/ajpendo.00396.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Reduced fetal glucose supply, induced experimentally or as a result of placental insufficiency, produces an early activation of fetal glucose production. The mechanisms and substrates used to fuel this increased glucose production rate remain unknown. We hypothesized that in response to hypoglycemia, induced experimentally with maternal insulin infusion, the fetal liver would increase uptake of lactate and amino acids (AA), which would combine with hormonal signals to support hepatic glucose production. To test this hypothesis, metabolic studies were done in six late gestation fetal sheep to measure hepatic glucose and substrate flux before (basal) and after [days (d)1 and 4] the start of hypoglycemia. Maternal and fetal glucose concentrations decreased by 50% on d1 and d4 (P < 0.05). The liver transitioned from net glucose uptake (basal, 5.1 ± 1.5 μmol/min) to output by d4 (2.8 ± 1.4 μmol/min; P < 0.05 vs. basal). The [U-¹³C]glucose tracer molar percent excess ratio across the liver decreased over the same period (basal: 0.98 ± 0.01, vs. d4: 0.89 ± 0.01, P < 0.05). Total hepatic AA uptake, but not lactate or pyruvate uptake, increased by threefold on d1 (P < 0.05) and remained elevated throughout the study. This AA uptake was driven largely by decreased glutamate output and increased glycine uptake. Fetal plasma concentrations of insulin were 50% lower, while cortisol and glucagon concentrations increased 56 and 86% during hypoglycemia (P < 0.05 for basal vs. d4). Thus increased hepatic AA uptake, rather than pyruvate or lactate uptake, and decreased fetal plasma insulin and increased cortisol and glucagon concentrations occur simultaneously with increased fetal hepatic glucose output in response to fetal hypoglycemia.
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Affiliation(s)
- Satya S Houin
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Laura D Brown
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Randall B Wilkening
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Stephanie R Thorn
- Perinatal Research Center, Department of Pediatrics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado
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Kuo YC, Chen IY, Chang SC, Wu SC, Hung TM, Lee PH, Shimotohno K, Chang MF. Hepatitis C virus NS5A protein enhances gluconeogenesis through upregulation of Akt-/JNK-PEPCK signalling pathways. Liver Int 2014; 34:1358-68. [PMID: 25360475 DOI: 10.1111/liv.12389] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infection is highly associated with the type 2 diabetes mellitus, but the detailed mechanisms by which the viral proteins are involved in the clinical outcome remain unclear. METHODS A cDNA microarray analysis was performed following introducing an NS5A-encoding plasmid or a control vector into a mouse system by hydrodynamics- based transfection. Differentially expressed genes that are associated with gluconeogenesis were selected and their expression levels in HCV patients, in NS5A-expressing systems, and in the viral subgenomic replicon system were further examined by real-time quantitative polymerase chain reaction and Western blot analysis. RESULTS Differential gene expression including an upregulation of the gluconeogenic rate-limiting enzyme phosphoenolpyruvate carboxykinase (PEPCK) compared with controls was detected in mouse hepatocytes expressing HCV NS5A and in HCV patients with diabetes. In addition, an NS5A-dependent increase in glucose production was demonstrated in human primary hepatocytes. The upregulation of PEPCK and peroxisome proliferator-activated receptor-c coactivator-1a (PGC-1a) were also detected in NS5A-expressing cells and in the viral genotype 1b subgenomic replicon system. Further studies demonstrated that the NS5A-mediated upregulation of PEPCK and PGC-1a genes were resulted from the activation of PI3K-Akt and JNK signalling pathways. In addition, the expression levels of the forkhead transcription factor FoxO1 and the liver-enriched transcription factor HNF-4a were increased in HCV NS5A expressing cells. CONCLUSIONS By upregulating the expression of PEPCK gene via its transactivators FoxO1 and HNF-4a, and the coactivator PGC-1a, the NS5A promotes the production of hepatic glucose which may contribute to the development of HCV-associated type 2 diabetes mellitus.
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Affiliation(s)
- Yi-Chen Kuo
- Institute of Biochemistry and Molecular Biology; National Taiwan University College of Medicine; Taipei Taiwan
| | - I-Yin Chen
- Institute of Biochemistry and Molecular Biology; National Taiwan University College of Medicine; Taipei Taiwan
- Institute of Microbiology; National Taiwan University College of Medicine; Taipei Taiwan
| | - Shin C. Chang
- Institute of Microbiology; National Taiwan University College of Medicine; Taipei Taiwan
| | - Shun-Chi Wu
- Institute of Biochemistry and Molecular Biology; National Taiwan University College of Medicine; Taipei Taiwan
| | - Tzu-Min Hung
- Department of Surgery; National Taiwan University Hospital; Taipei Taiwan
- Department of Medical Research; E-DA Hospital; Kaohsiung Taiwan
| | - Po-Huang Lee
- Department of Surgery; National Taiwan University Hospital; Taipei Taiwan
| | - Kunitada Shimotohno
- Laboratory of Human Tumor Viruses; Institute of Virus Research; Kyoto University; Kyoto Japan
| | - Ming-Fu Chang
- Institute of Biochemistry and Molecular Biology; National Taiwan University College of Medicine; Taipei Taiwan
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Lie S, Morrison JL, Williams-Wyss O, Suter CM, Humphreys DT, Ozanne SE, Zhang S, MacLaughlin SM, Kleemann DO, Walker SK, Roberts CT, McMillen IC. Impact of embryo number and maternal undernutrition around the time of conception on insulin signaling and gluconeogenic factors and microRNAs in the liver of fetal sheep. Am J Physiol Endocrinol Metab 2014; 306:E1013-24. [PMID: 24496309 PMCID: PMC4010656 DOI: 10.1152/ajpendo.00553.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/29/2014] [Indexed: 01/14/2023]
Abstract
This study aimed to determine whether exposure of the oocyte and/or embryo to maternal undernutrition results in the later programming of insulin action in the liver and factors regulating gluconeogenesis. To do this, we collect livers from singleton and twin fetal sheep that were exposed to periconceptional (PCUN; -60 to 7 days) or preimplantation (PIUN; 0-7 days) undernutrition at 136-138 days of gestation (term = 150 days). The mRNA and protein abundance of insulin signaling and gluconeogenic factors were then quantified using qRT-PCR and Western blotting, respectively, and global microRNA expression was quantified using deep sequencing methodology. We found that hepatic PEPCK-C mRNA (P < 0.01) and protein abundance and the protein abundance of IRS-1 (P < 0.01), p110β (P < 0.05), PTEN (P < 0.05), CREB (P < 0.01), and pCREB (Ser(133); P < 0.05) were decreased in the PCUN and PIUN singletons. In contrast, hepatic protein abundance of IRS-1 (P < 0.01), p85 (P < 0.01), p110β (P < 0.001), PTEN (P < 0.01), Akt2 (P < 0.01), p-Akt (Ser(473); P < 0.01), and p-FOXO-1 (Thr24) (P < 0.01) was increased in twins. There was a decrease in PEPCK-C mRNA (P < 0.01) but, paradoxically, an increase in PEPCK-C protein (P < 0.001) in twins. Both PCUN and PIUN altered the hepatic expression of 23 specific microRNAs. We propose that the differential impact of maternal undernutrition in the presence of one or two embryos on mRNAs and proteins involved in the insulin signaling and gluconeogenesis is explained by changes in the expression of a suite of specific candidate microRNAs.
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Affiliation(s)
- Shervi Lie
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
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Rattanatray L, Muhlhausler BS, Nicholas LM, Morrison JL, McMillen IC. Impact of maternal overnutrition on gluconeogenic factors and methylation of the phosphoenolpyruvate carboxykinase promoter in the fetal and postnatal liver. Pediatr Res 2014; 75:14-21. [PMID: 24452591 DOI: 10.1038/pr.2013.178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 06/03/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND Exposure to maternal obesity or hyperglycemia increases the risk of obesity and poor glucose tolerance in the offspring. We hypothesized that maternal overnutrition in late pregnancy would result in (i) lower methylation in the promoter region of the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C; PCK1) and (ii) higher expression of hepatic gluconeogenic factors in the fetal and postnatal lamb. METHODS Ewes were fed 100% (n = 18) or ~155% (n = 17) of energy requirements from 115 d gestation, and livers were collected at ~140 d gestation or 30 d postnatal age. RESULTS Maternal overnutrition resulted in a decrease in hepatic expression of the mitochondrial form of PEPCK (PEPCK-M; PCK2) but not of PEPCK-C or glucose-6-phosphatase (G6PHOS) before and after birth. Hepatic expression of peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1), peroxisome proliferator-activated receptor α (PPARα), PEPCK-C, G6PHOS, and 11β hydroxysteroid dehydrogenase type 1 (11βHSD1), but not PEPCK-M, was higher in the postnatal lamb compared with that in the fetal lamb. The level of PCK1 methylation was paradoxically approximately twofold higher in the postnatal liver compared with that in the fetal liver. CONCLUSION Maternal overnutrition programs a decrease in hepatic PEPCK-M in the offspring and as ~50% of total hepatic PEPCK is PEPCK-M, the longer-term consequences of this decrease may be significant.
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Affiliation(s)
- Leewen Rattanatray
- 1] School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia [2] Discipline of Physiology, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Beverly S Muhlhausler
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - Lisa M Nicholas
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - Janna L Morrison
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - I Caroline McMillen
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
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Gadhia MM, Maliszewski AM, O'Meara MC, Thorn SR, Lavezzi JR, Limesand SW, Hay WW, Brown LD, Rozance PJ. Increased amino acid supply potentiates glucose-stimulated insulin secretion but does not increase β-cell mass in fetal sheep. Am J Physiol Endocrinol Metab 2013; 304:E352-62. [PMID: 23211516 PMCID: PMC3566506 DOI: 10.1152/ajpendo.00377.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amino acids and glucose acutely stimulate fetal insulin secretion. In isolated adult pancreatic islets, amino acids potentiate glucose-stimulated insulin secretion (GSIS), but whether amino acids have this same effect in the fetus is unknown. Therefore, we tested the effects of increased fetal amino acid supply on GSIS and morphology of the pancreas. We hypothesized that increasing fetal amino acid supply would potentiate GSIS. Singleton fetal sheep received a direct intravenous infusion of an amino acid mixture (AA) or saline (CON) for 10-14 days during late gestation to target a 25-50% increase in fetal branched-chain amino acids (BCAA). Early-phase GSIS increased 150% in the AA group (P < 0.01), and this difference was sustained for the duration of the hyperglycemic clamp (105 min) (P < 0.05). Glucose-potentiated arginine-stimulated insulin secretion (ASIS), pancreatic insulin content, and pancreatic glucagon content were similar between groups. β-Cell mass and area were unchanged between groups. Baseline and arginine-stimulated glucagon concentrations were increased in the AA group (P < 0.05). Pancreatic α-cell mass and area were unchanged. Fetal and pancreatic weights were similar. We conclude that a sustained increase of amino acid supply to the normally growing late-gestation fetus potentiated fetal GSIS but did not affect the morphology or insulin content of the pancreas. We speculate that increased β-cell responsiveness (insulin secretion) following increased amino acid supply may be due to increased generation of secondary messengers in the β-cell. This may be enhanced by the paracrine action of glucagon on the β-cell.
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Affiliation(s)
- Monika M Gadhia
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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19
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Thorn SR, Brown LD, Rozance PJ, Hay WW, Friedman JE. Increased hepatic glucose production in fetal sheep with intrauterine growth restriction is not suppressed by insulin. Diabetes 2013; 62:65-73. [PMID: 22933111 PMCID: PMC3526037 DOI: 10.2337/db11-1727] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Intrauterine growth restriction (IUGR) increases the risk for metabolic disease and diabetes, although the developmental origins of this remain unclear. We measured glucose metabolism during basal and insulin clamp periods in a fetal sheep model of placental insufficiency and IUGR. Compared with control fetuses (CON), fetuses with IUGR had increased basal glucose production rates and hepatic PEPCK and glucose-6-phosphatase expression, which were not suppressed by insulin. In contrast, insulin significantly increased peripheral glucose utilization rates in CON and IUGR fetuses. Insulin robustly activated AKT, GSK3β, and forkhead box class O (FOXO)1 in CON and IUGR fetal livers. IUGR livers, however, had increased basal FOXO1 phosphorylation, nuclear FOXO1 expression, and Jun NH(2)-terminal kinase activation during hyperinsulinemia. Expression of peroxisome proliferator-activated receptor γ coactivator 1α and hepatocyte nuclear factor-4α were increased in IUGR livers during basal and insulin periods. Cortisol and norepinephrine concentrations were positively correlated with glucose production rates. Isolated IUGR hepatocytes maintained increased glucose production in culture. In summary, fetal sheep with IUGR have increased hepatic glucose production, which is not suppressed by insulin despite insulin sensitivity for peripheral glucose utilization. These data are consistent with a novel mechanism involving persistent transcriptional activation in the liver that seems to be unique in the fetus with IUGR.
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Affiliation(s)
- Stephanie R Thorn
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado, USA.
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20
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Lavezzi JR, Thorn SR, O'Meara MC, LoTurco D, Brown LD, Hay WW, Rozance PJ. Increased fetal insulin concentrations for one week fail to improve insulin secretion or β-cell mass in fetal sheep with chronically reduced glucose supply. Am J Physiol Regul Integr Comp Physiol 2012; 304:R50-8. [PMID: 23135788 DOI: 10.1152/ajpregu.00413.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maternal undernutrition during pregnancy and placental insufficiency are characterized by impaired development of fetal pancreatic β-cells. Prolonged reduced glucose supply to the fetus is a feature of both. It is unknown if reduced glucose supply, independent of other complications of maternal undernutrition and placental insufficiency, would cause similar β-cell defects. Therefore, we measured fetal insulin secretion and β-cell mass following prolonged reduced fetal glucose supply in sheep. We also tested whether restoring physiological insulin concentrations would correct any β-cell defects. Pregnant sheep received either a direct saline infusion (CON = control, n = 5) or an insulin infusion (HG = hypoglycemic, n = 5) for 8 wk in late gestation (75 to 134 days) to decrease maternal glucose concentrations and reduce fetal glucose supply. A separate group of HG fetuses also received a direct fetal insulin infusion for the final week of the study with a dextrose infusion to prevent a further fall in glucose concentration [hypoglycemic + insulin (HG+I), n = 4]. Maximum glucose-stimulated insulin concentrations were 45% lower in HG fetuses compared with CON fetuses. β-Cell, pancreatic, and fetal mass were 50%, 37%, and 40% lower in HG compared with CON fetuses, respectively (P < 0.05). Insulin secretion and β-cell mass did not improve in the HG+I fetuses. These results indicate that chronically reduced fetal glucose supply is sufficient to reduce pancreatic insulin secretion in response to glucose, primarily due to reduced pancreatic and β-cell mass, and is not correctable with insulin.
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Affiliation(s)
- Jinny R Lavezzi
- Perinatal Research Center, Section of Neonatology, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, USA
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21
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Thorn SR, Sekar SM, Lavezzi JR, O'Meara MC, Brown LD, Hay WW, Rozance PJ. A physiological increase in insulin suppresses gluconeogenic gene activation in fetal sheep with sustained hypoglycemia. Am J Physiol Regul Integr Comp Physiol 2012; 303:R861-9. [PMID: 22933022 DOI: 10.1152/ajpregu.00331.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reduced maternal glucose supply to the fetus and resulting fetal hypoglycemia and hypoinsulinemia activate fetal glucose production as a means to maintain cellular glucose uptake. However, this early activation of fetal glucose production may be accompanied by hepatic insulin resistance. We tested the capacity of a physiological increase in insulin to suppress fetal hepatic gluconeogenic gene activation following sustained hypoglycemia to determine whether hepatic insulin sensitivity is maintained. Control fetuses (CON), hypoglycemic fetuses induced by maternal insulin infusion for 8 wk (HG), and 8 wk HG fetuses that received an isoglycemic insulin infusion for the final 7 days (HG+INS) were studied. Glucose and insulin concentrations were 60% lower in HG compared with CON fetuses. Insulin was 50% higher in HG+INS compared with CON and four-fold higher compared with HG fetuses. Expression of the hepatic gluconeogenic genes, PCK1, G6PC, FBP1, GLUT2, and PGC1A was increased in the HG and reduced in the HG+INS liver. Expression of the insulin-regulated glycolytic and lipogenic genes, PFKL and FAS, was increased in the HG+INS liver. Total FOXO1 protein expression, a gluconeogenic activator, was 60% higher in the HG liver. Despite low glucose, insulin, and IGF1 concentrations, phosphorylation of AKT and ERK was higher in the HG liver. Thus, a physiological increase in fetal insulin is sufficient for suppression of gluconeogenic genes and activation of glycolytic and lipogenic genes in the HG fetal liver. These results demonstrate that fetuses exposed to sustained hypoglycemia have maintained hepatic insulin action in contrast to fetuses exposed to placental insufficiency.
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Affiliation(s)
- Stephanie R Thorn
- Perinatal Research Center, Department of Pediatrics, Univ. of Colorado School of Medicine, Aurora 80045, USA.
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Shoji I, Deng L, Hotta H. Molecular mechanism of hepatitis C virus-induced glucose metabolic disorders. Front Microbiol 2012; 2:278. [PMID: 22291689 PMCID: PMC3263922 DOI: 10.3389/fmicb.2011.00278] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 12/25/2011] [Indexed: 12/20/2022] Open
Abstract
Hepatitis C virus (HCV) infection causes not only intrahepatic diseases but also extrahepatic manifestations, including metabolic disorders. Chronic HCV infection is often associated with type 2 diabetes. However, the precise mechanism underlying this association is still unclear. Glucose is transported into hepatocytes via glucose transporter 2 (GLUT2). Hepatocytes play a crucial role in maintaining plasma glucose homeostasis via the gluconeogenic and glycolytic pathways. We have been investigating the molecular mechanism of HCV-related type 2 diabetes using HCV RNA replicon cells and HCV J6/JFH1 system. We found that HCV replication down-regulates cell surface expression of GLUT2 at the transcriptional level. We also found that HCV infection promotes hepatic gluconeogenesis in HCV J6/JFH1-infected Huh-7.5 cells. HCV infection transcriptionally up-regulated the genes for phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase), the rate-limiting enzymes for hepatic gluconeogenesis. Gene expression of PEPCK and G6Pase was regulated by the transcription factor forkhead box O1 (FoxO1) in HCV-infected cells. Phosphorylation of FoxO1 at Ser319 was markedly diminished in HCV-infected cells, resulting in increased nuclear accumulation of FoxO1. HCV NS5A protein was directly linked with the FoxO1-dependent increased gluconeogenesis. This paper will discuss the current model of HCV-induced glucose metabolic disorders.
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Affiliation(s)
- Ikuo Shoji
- Division of Microbiology, Center for Infectious Diseases, Kobe University Graduate School of Medicine Kobe, Japan
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Thorn SR, Rozance PJ, Brown LD, Hay WW. The intrauterine growth restriction phenotype: fetal adaptations and potential implications for later life insulin resistance and diabetes. Semin Reprod Med 2011; 29:225-36. [PMID: 21710398 DOI: 10.1055/s-0031-1275516] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The intrauterine growth restricted (IUGR) fetus develops unique metabolic adaptations in response to exposure to reduced nutrient supply. These adaptations provide survival value for the fetus by enhancing the capacity of the fetus to take up and use nutrients, thereby reducing the need for nutrient supply. Each organ and tissue in the fetus adapts differently, with the brain showing the greatest capacity for maintaining nutrient supply and growth. Such adaptations, if persistent, also have the potential in later life to promote nutrient uptake and storage, which directly lead to complications of obesity, insulin resistance, reduced insulin production, and type 2 diabetes.
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Hepatitis C virus infection promotes hepatic gluconeogenesis through an NS5A-mediated, FoxO1-dependent pathway. J Virol 2011; 85:8556-68. [PMID: 21697492 DOI: 10.1128/jvi.00146-11] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection is often associated with type 2 diabetes. However, the precise mechanism underlying this association is still unclear. Here, using Huh-7.5 cells either harboring HCV-1b RNA replicons or infected with HCV-2a, we showed that HCV transcriptionally upregulated the genes for phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase), the rate-limiting enzymes for hepatic gluconeogenesis. In this way, HCV enhanced the cellular production of glucose 6-phosphate (G6P) and glucose. PEPCK and G6Pase gene expressions are controlled by the transcription factor forkhead box O1 (FoxO1). We observed that although neither the mRNA levels nor the protein levels of FoxO1 expression were affected by HCV, the level of phosphorylation of FoxO1 at Ser319 was markedly diminished in HCV-infected cells compared to the control cells, resulting in an increased nuclear accumulation of FoxO1, which is essential for sustaining its transcriptional activity. It was unlikely that the decreased level of FoxO1 phosphorylation was mediated through Akt inactivation, as we observed an increased phosphorylation of Akt at Ser473 in HCV-infected cells compared to control cells. By using specific inhibitors of c-Jun N-terminal kinase (JNK) and reactive oxygen species (ROS), we demonstrated that HCV infection induced JNK activation via increased mitochondrial ROS production, resulting in decreased FoxO1 phosphorylation, FoxO1 nuclear accumulation, and, eventually, increased glucose production. We also found that HCV NS5A mediated increased ROS production and JNK activation, which is directly linked with the FoxO1-dependent increased gluconeogenesis. Taken together, these observations suggest that HCV promotes hepatic gluconeogenesis through an NS5A-mediated, FoxO1-dependent pathway.
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Catecholamines mediate multiple fetal adaptations during placental insufficiency that contribute to intrauterine growth restriction: lessons from hyperthermic sheep. J Pregnancy 2011; 2011:740408. [PMID: 21773031 PMCID: PMC3135098 DOI: 10.1155/2011/740408] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 03/11/2011] [Indexed: 01/22/2023] Open
Abstract
Placental insufficiency (PI) prevents adequate delivery of nutrients to the developing fetus and creates a chronic state of hypoxemia and hypoglycemia. In response, the malnourished fetus develops a series of stress hormone-mediated metabolic adaptations to preserve glucose for vital tissues at the expense of somatic growth. Catecholamines suppress insulin secretion to promote glucose sparing for insulin-independent tissues (brain, nerves) over insulin-dependent tissues (skeletal muscle, liver, and adipose). Likewise, premature induction of hepatic gluconeogenesis helps maintain fetal glucose and appears to be stimulated by both norepinephrine and glucagon. Reduced glucose oxidation rate in PI fetuses creates a surplus of glycolysis-derived lactate that serves as substrate for hepatic gluconeogenesis. These adrenergically influenced adaptive responses promote in utero survival but also cause asymmetric intrauterine growth restriction and small-for-gestational-age infants that are at greater risk for serious metabolic disorders throughout postnatal life, including obesity and type II diabetes.
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Kamat A, Nijland MJ, McDonald TJ, Cox LA, Nathanielsz PW, Li C. Moderate global reduction in maternal nutrition has differential stage of gestation specific effects on {beta}1- and {beta}2-adrenergic receptors in the fetal baboon liver. Reprod Sci 2010; 18:398-405. [PMID: 21079239 DOI: 10.1177/1933719110386496] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hepatic β-adrenergic receptors (β-ARs) play a pivotal role in mobilization of reserves via gluconeogenesis and glycogenolysis to supply the animal with its energy needs during decreased nutrient availability. Using a unique nutrient-deprived baboon model, we have demonstrated for the first time that immunoreactive hepatic β(1)- and β(2)-AR subtypes are regionally distributed and localized on cells around the central lobular vein in 0.5 and 0.9 gestation (G) fetuses of ad libitum fed control (CTR) and maternal nutrient restricted (MNR) mothers. Furthermore, MNR decreased fetal liver immunoreactive β(1)-AR and increased immunoreactive β(2)-AR at 0.5G. However, at 0.9G, immunohistochemistry and Western blot analysis revealed a decrease in β(1)-AR and no change in β(2)-AR levels. Thus, MNR in a nonhuman primate species has effects on hepatic β(1)- and β(2)-ARs that are receptor- and gestation stage-specific and may represent compensatory systems whose effects would increase glucose availability in the presence of nutrient deprivation.
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Affiliation(s)
- Amrita Kamat
- Department of Medicine, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Green AS, Limesand SW. Remembering development - epigenetic responses to fetal malnutrition. J Physiol 2010; 588:1379-80. [PMID: 20436037 DOI: 10.1113/jphysiol.2010.189787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Alice S Green
- Department of Animal Sciences, University of Arizona, 1650 East Limberlost Drive, Tucson, AZ 85719, USA
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Abstract
Low birth weight is an important risk factor for impaired glucose tolerance and diabetes later in life. One hypothesis is that fetal beta-cells inherit a persistent defect as a developmental response to fetal malnutrition, a primary cause of intrauterine growth restriction (IUGR). Our understanding of fetal programing events in the human endocrine pancreas is limited, but several animal models of IUGR extend our knowledge of developmental programing in beta-cells. Pathological outcomes such as beta-cell dysfunction, impaired glucose tolerance, and diabetes are often observed in adult offspring from these animal models, similar to the associations of low birth weight and metabolic diseases in humans. However, the identified mechanisms underlying beta-cell dysfunction across models and species are varied, likely resulting from the different methodologies used to induce experimental IUGR, as well as from intraspecies differences in pancreas development. In this review, we first present the evidence for human beta-cell dysfunction being associated with low birth weight or IUGR. We then evaluate relevant animal models of IUGR, focusing on the strengths of each, in order to define critical periods and types of nutrient deficiencies that can lead to impaired beta-cell function. These findings frame our current knowledge of beta-cell developmental programing and highlight future research directions to clarify the mechanisms of beta-cell dysfunction for human IUGR.
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Affiliation(s)
- Alice S. Green
- Department of Animal Sciences, University of Arizona, Tucson, AZ
| | - Paul J. Rozance
- Department of Pediatrics, University of Colorado, Denver, CO
| | - Sean W. Limesand
- Department of Animal Sciences, University of Arizona, Tucson, AZ
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Nijland MJ, Mitsuya K, Li C, Ford S, McDonald TJ, Nathanielsz PW, Cox LA. Epigenetic modification of fetal baboon hepatic phosphoenolpyruvate carboxykinase following exposure to moderately reduced nutrient availability. J Physiol 2010; 588:1349-59. [PMID: 20176628 DOI: 10.1113/jphysiol.2009.184168] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Decreased maternal nutrient availability during pregnancy induces compensatory fetal metabolic and endocrine responses. Knowledge of cellular changes involved is critical to understanding normal and abnormal development. Several studies in rodents and sheep report increased fetal plasma cortisol and associated increased gluconeogenesis in response to maternal nutrient reduction (MNR) but observations in primates are lacking. We determined MNR effects on fetal liver phosphoenolpyruvate carboxykinase 1 (protein, PEPCK1; gene, PCK1 orthologous/homologous human chromosomal region 20q13.31) at 0.9 gestation (G). Female baboon social groups were fed ad libitum (control, CTR) or 70% CTR (MNR) from 0.16 to 0.9G when fetuses were delivered by caesarean section under general anaesthesia. Plasma cortisol was elevated in fetuses of MNR mothers (P < 0.05). Immunoreactive PEPCK1 protein was located around the liver lobule central vein and was low in CTR fetuses but rose to 63% of adult levels in MNR fetuses. PCK1 mRNA measured by QRT-PCR increased in MNR (2.3-fold; P < 0.05) while the 25% rise in protein by Western blot analysis was not significant. PCK1 promoter methylation analysis using bisulfite sequencing was significantly reduced in six out of nine CpG-dinucleotides evaluated in MNR compared with CTR liver samples. In conclusion, these are the first data from a fetal non-human primate indicating hypomethylation of the PCK1 promoter in the liver following moderate maternal nutrient reduction.
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Affiliation(s)
- Mark J Nijland
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center, San Antonio, TX, USA
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Cotyledonary responses to maternal selenium and dietary restriction may influence alterations in fetal weight and fetal liver glycogen in sheep. Anim Reprod Sci 2010; 117:216-25. [DOI: 10.1016/j.anireprosci.2009.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 05/04/2009] [Accepted: 05/11/2009] [Indexed: 11/19/2022]
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Hay WW, Raju TN, Higgins RD, Kalhan SC, Devaskar SU. Knowledge gaps and research needs for understanding and treating neonatal hypoglycemia: workshop report from Eunice Kennedy Shriver National Institute of Child Health and Human Development. J Pediatr 2009; 155:612-7. [PMID: 19840614 PMCID: PMC3857033 DOI: 10.1016/j.jpeds.2009.06.044] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/01/2009] [Accepted: 06/22/2009] [Indexed: 11/29/2022]
Affiliation(s)
- William W Hay
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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Li C, Schlabritz-Loutsevitch NE, Hubbard GB, Han V, Nygard K, Cox LA, McDonald TJ, Nathanielsz PW. Effects of maternal global nutrient restriction on fetal baboon hepatic insulin-like growth factor system genes and gene products. Endocrinology 2009; 150:4634-42. [PMID: 19574404 PMCID: PMC2754676 DOI: 10.1210/en.2008-1648] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Knowledge of altered maternal nutrition effects on growth-regulating systems is critical to understanding normal and abnormal fetal development. There are many reports of hepatic fetal IGF system responses to maternal nutrient restriction (MNR) during pregnancy in rodents and sheep but none in nonhuman primates. We determined effects of MNR on the fetal baboon hepatic IGF system. Social groups of female baboons were fed ad libitum, controls, or 70% controls (MNR) from 0.16 to 0.5 gestation and fetuses delivered by cesarean section. Fetal liver tissue was analyzed for IGF-I, IGF-II, and IGF binding protein (IGFBP)-3 mRNA by in situ hybridization and quantitative RT-PCR and protein by immunohistochemistry (IHC); IGF-I receptor, IGF-II receptor by quantitative RT-PCR and IHC and IGFBP-1 by in situ hybridization and IHC. MNR did not alter fetal body or liver weight. Fetal hepatic glycogen staining increased with MNR. MNR reduced fetal hepatic IGF-I and IGF-II and increased IGFBP-1 mRNA and decreased IGF-I, IGF-II, IGF-I receptor, and IGF-II receptor protein and increased protein for IGFBP-1 and IGFBP-3. MNR increased caspase-3, indicating apoptosis and decreased Akt staining, indicating decreased nutrient sensing. In conclusion, whereas fetal body and liver weights did not change in response to moderate MNR during the first half of baboon pregnancy, the major indices of function of the hepatic IGF system measured were all reduced.
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Affiliation(s)
- Cun Li
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, Texas 78229, USA.
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Rozance PJ, Crispo MM, Barry JS, O'Meara MC, Frost MS, Hansen KC, Hay WW, Brown LD. Prolonged maternal amino acid infusion in late-gestation pregnant sheep increases fetal amino acid oxidation. Am J Physiol Endocrinol Metab 2009; 297:E638-46. [PMID: 19602583 PMCID: PMC2739698 DOI: 10.1152/ajpendo.00192.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein supplementation during human pregnancy does not improve fetal growth and may increase small-for-gestational-age birth rates and mortality. To define possible mechanisms, sheep with twin pregnancies were infused with amino acids (AA group, n = 7) or saline (C group, n = 4) for 4 days during late gestation. In the AA group, fetal plasma leucine, isoleucine, valine, and lysine concentrations were increased (P < 0.05), and threonine was decreased (P < 0.05). In the AA group, fetal arterial pH (7.365 +/- 0.007 day 0 vs. 7.336 +/- 0.012 day 4, P < 0.005), hemoglobin-oxygen saturation (46.2 +/- 2.6 vs. 37.8 +/- 3.6%, P < 0.005), and total oxygen content (3.17 +/- 0.17 vs. 2.49 +/- 0.20 mmol/l, P < 0.0001) were decreased on day 4 compared with day 0. Fetal leucine disposal did not change (9.22 +/- 0.73 vs. 8.09 +/- 0.63 micromol x min(-1) x kg(-1), AA vs. C), but the rate of leucine oxidation increased 43% in the AA group (2.63 +/- 0.16 vs. 1.84 +/- 0.24 micromol x min(-1) x kg(-1), P < 0.05). Fetal oxygen utilization tended to be increased in the AA group (327 +/- 23 vs. 250 +/- 29 micromol x min(-1) x kg(-1), P = 0.06). Rates of leucine incorporation into fetal protein (5.19 +/- 0.97 vs. 5.47 +/- 0.89 micromol x min(-1) x kg(-1), AA vs. C), release from protein breakdown (4.20 +/- 0.95 vs. 4.62 +/- 0.74 micromol x min(-1) x kg(-1)), and protein accretion (1.00 +/- 0.30 vs. 0.85 +/- 0.25 micromol x min(-1) x kg(-1)) did not change. Consistent with these data, there was no change in the fetal skeletal muscle ubiquitin ligases MaFBx1 or MuRF1 or in the protein synthesis regulators 4E-BP1, eEF2, eIF2alpha, and p70(S6K). Decreased concentrations of certain essential amino acids, increased amino acid oxidation, fetal acidosis, and fetal hypoxia are possible mechanisms to explain fetal toxicity during maternal amino acid supplementation.
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Affiliation(s)
- Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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Ford SP, Zhang L, Zhu M, Miller MM, Smith DT, Hess BW, Moss GE, Nathanielsz PW, Nijland MJ. Maternal obesity accelerates fetal pancreatic beta-cell but not alpha-cell development in sheep: prenatal consequences. Am J Physiol Regul Integr Comp Physiol 2009; 297:R835-43. [PMID: 19605766 DOI: 10.1152/ajpregu.00072.2009] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maternal obesity affects offspring weight, body composition, and organ function, increasing diabetes and metabolic syndrome risk. We determined effects of maternal obesity and a high-energy diet on fetal pancreatic development. Sixty days prior to breeding, ewes were assigned to control [100% of National Research Council (NRC) recommendations] or obesogenic (OB; 150% NRC) diets. At 75 days gestation, OB ewes exhibited elevated insulin-to-glucose ratios at rest and during a glucose tolerance test, demonstrating insulin resistance compared with control ewes. In fetal studies, ewes ate their respective diets from 60 days before to 75 days after conception when animals were euthanized under general anesthesia. OB and control ewes increased in body weight by approximately 43% and approximately 6%, respectively, from diet initiation until necropsy. Although all organs were heavier in fetuses from OB ewes, only pancreatic weight increased as a percentage of fetal weight. Blood glucose, insulin, and cortisol were elevated in OB ewes and fetuses on day 75. Insulin-positive cells per unit pancreatic area were 50% greater in fetuses from OB ewes as a result of increased beta-cell mitoses rather than decreased programmed cell death. Lambs of OB ewes were born earlier but weighed the same as control lambs; however, their crown-to-rump length was reduced, and their fat mass was increased. We conclude that increased systemic insulin in fetuses from OB ewes results from increased glucose exposure and/or cortisol-induced accelerated fetal beta-cell maturation and may contribute to premature beta-cell function loss and predisposition to obesity and metabolic disease in offspring.
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Affiliation(s)
- Stephen P Ford
- Center for the Study of Fetal Programming, Department of Animal Science, University of Wyoming, Laramie, Wyoming, USA
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Thorn SR, Regnault TRH, Brown LD, Rozance PJ, Keng J, Roper M, Wilkening RB, Hay WW, Friedman JE. Intrauterine growth restriction increases fetal hepatic gluconeogenic capacity and reduces messenger ribonucleic acid translation initiation and nutrient sensing in fetal liver and skeletal muscle. Endocrinology 2009; 150:3021-30. [PMID: 19342452 PMCID: PMC2703533 DOI: 10.1210/en.2008-1789] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Expression of key metabolic genes and proteins involved in mRNA translation, energy sensing, and glucose metabolism in liver and skeletal muscle were investigated in a late-gestation fetal sheep model of placental insufficiency intrauterine growth restriction (PI-IUGR). PI-IUGR fetuses weighed 55% less; had reduced oxygen, glucose, isoleucine, insulin, and IGF-I levels; and had 40% reduction in net branched chain amino acid uptake. In PI-IUGR skeletal muscle, levels of insulin receptor were increased 80%, whereas phosphoinositide-3 kinase (p85) and protein kinase B (AKT2) were reduced by 40%. Expression of eukaryotic initiation factor-4e was reduced 45% in liver, suggesting a unique mechanism limiting translation initiation in PI-IUGR liver. There was either no change (AMP activated kinase, mammalian target of rapamycin) or a paradoxical decrease (protein phosphatase 2A, eukaryotic initiation factor-2 alpha) in activation of major energy and cell stress sensors in PI-IUGR liver and skeletal muscle. A 13- to 20-fold increase in phosphoenolpyruvate carboxykinase and glucose 6 phosphatase mRNA expression in the PI-IUGR liver was-associated with a 3-fold increase in peroxisome proliferator-activated receptor-gamma coactivator-1 alpha mRNA and increased phosphorylation of cAMP response element binding protein. Thus PI-IUGR is-associated with reduced branched chain amino acid uptake and growth factors, yet up-regulation of proximal insulin signaling and a marked increase in the gluconeogenic pathway. Lack of activation of several energy and stress sensors in fetal liver and skeletal muscle, despite hypoxia and low energy status, suggests a novel strategy for survival in the PI-IUGR fetus but with potential maladaptive consequences for reduced nutrient sensing and insulin sensitivity in postnatal life.
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Affiliation(s)
- Stephanie R Thorn
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado 80045, USA
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Limesand SW, Rozance PJ, Brown LD, Hay WW. Effects of chronic hypoglycemia and euglycemic correction on lysine metabolism in fetal sheep. Am J Physiol Endocrinol Metab 2009; 296:E879-87. [PMID: 19190258 PMCID: PMC2670627 DOI: 10.1152/ajpendo.90832.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, we determined rates of lysine metabolism in fetal sheep during chronic hypoglycemia and following euglycemic recovery and compared results with normal, age-matched euglycemic control fetuses to explain the adaptive response of protein metabolism to low glucose concentrations. Restriction of the maternal glucose supply to the fetus lowered the net rates of fetal (umbilical) glucose (42%) and lactate (36%) uptake, causing compensatory alterations in fetal lysine metabolism. The plasma lysine concentration was 1.9-fold greater in hypoglycemic compared with control fetuses, but the rate of fetal (umbilical) lysine uptake was not different. In the hypoglycemic fetuses, the lysine disposal rate also was higher than in control fetuses due to greater rates of lysine flux back into the placenta and into fetal tissue. The rate of CO2 excretion from lysine decarboxylation was 2.4-fold higher in hypoglycemic than control fetuses, indicating greater rates of lysine oxidative metabolism during chronic hypoglycemia. No differences were detected for rates of fetal protein accretion or synthesis between hypoglycemic and control groups, although there was a significant increase in the rate of protein breakdown (P<0.05) in the hypoglycemic fetuses, indicating small changes in each rate. This was supported by elevated muscle specific ubiquitin ligases and greater concentrations of 4E-BP1. Euglycemic recovery after chronic hypoglycemia normalized all fluxes and actually lowered the rate of lysine decarboxylation compared with control fetuses (P<0.05). These results indicate that chronic hypoglycemia increases net protein breakdown and lysine oxidative metabolism, both of which contribute to slower rates of fetal growth over time. Furthermore, euglycemic correction for 5 days returns lysine fluxes to normal and causes an overcorrection of lysine oxidation.
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Affiliation(s)
- Sean W Limesand
- Department of Animal Sciences, University of Arizona, 1650 E. Limberlost Dr., Tucson, AZ 85719, USA.
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Current world literature. Curr Opin Pediatr 2009; 21:272-80. [PMID: 19307901 DOI: 10.1097/mop.0b013e32832ad5c0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
PURPOSE OF REVIEW Intrauterine growth restriction (IUGR) is associated with an increased propensity to develop adult-onset disease and is described by the developmental origins of adult disease hypothesis. Sequelae of fetal growth restriction include metabolic disease as well as nonmetabolic disorders. Although it has become clear that the morbidities associated with IUGR are complex and result from disruptions to multiple pathways and multiple organs, the mechanisms driving the long-term effects are only just beginning to be understood. RECENT FINDINGS IUGR affects most organ systems by either interrupting developmental processes such as apoptosis or producing lasting changes to levels of key regulatory factors. Both of these are associated with an often persistent change in gene expression. Epigenetic modulation of transcription is a mechanism that is at least partially responsible for this. IUGR is accompanied by changes in the quantity and activity of enzymes responsible for making modifications to chromatin as well as global and gene-specific modifications of chromatin. SUMMARY The subtle adjustments needed to ensure developmental plasticity in IUGR are provided by epigenetic modulation of critical genes. Translating the messages of the epigenetic profile and identifying the players that mediate the effects remains one of the major challenges in the field. An understanding of the mechanisms driving the epigenetic changes will facilitate identification of dietary and pharmaceutical approaches that can be applied in the postnatal period.
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Gentili S, Morrison JL, McMillen IC. Intrauterine growth restriction and differential patterns of hepatic growth and expression of IGF1, PCK2, and HSDL1 mRNA in the sheep fetus in late gestation. Biol Reprod 2009; 80:1121-7. [PMID: 19208549 DOI: 10.1095/biolreprod.108.073569] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Fetal adaptations to periods of substrate deprivation can result in the programming of glucose intolerance, insulin resistance, and metabolic dysfunction in later life. Placental insufficiency can be associated with either sparing or sacrifice of fetal liver growth, and these different responses may have different metabolic consequences. It is unclear what intrahepatic mechanisms determine the differential responses of the fetal liver to substrate restriction. We investigated the effects of placental restriction (PR) on liver growth and the hepatic expression of SLC2A1, IGF1, IGF2, IGF1R, IGF2R, PPARGC1A, PPARA, PRKAA1, PRKAA2, PCK2, and HSDL1 mRNA in fetal sheep at 140-145 days of gestation. A mean gestational arterial partial pressure of oxygen less than 17 mmHg was defined as hypoxic, and a relative liver of weight more than 2 SD below the mean liver weight of controls was defined as reduced liver growth. Fetuses therefore were defined as control-normoxic (C-N; n = 9), PR-normoxic (PR-N; n = 7), PR-hypoxic (PR-H; n = 8), or PR-hypoxic reduced liver growth (PR-H RLG; n = 4). Hepatic SLC2A1 mRNA expression was highest (P < 0.05) in the PR-H fetuses, in which liver growth was maintained. Expression of IGF1 mRNA was decreased (P < 0.05) only in the PR-H RLG group. Hepatic expression of HSDL1, PPARGC1A, and PCK2 mRNA also were increased (P < 0.05) in the PR-H RLG fetuses. The present study highlights that intrahepatic responses to fetal substrate restriction may exist that protect the liver from decreased growth and, potentially, from a decreased responsiveness to the actions of insulin in postnatal life.
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Affiliation(s)
- Sheridan Gentili
- Early Origins of Adult Health Research Group, Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, South Australia, Australia.
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