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Burtscher J, Niedermeier M, Hüfner K, van den Burg E, Kopp M, Stoop R, Burtscher M, Gatterer H, Millet GP. The interplay of hypoxic and mental stress: Implications for anxiety and depressive disorders. Neurosci Biobehav Rev 2022; 138:104718. [PMID: 35661753 DOI: 10.1016/j.neubiorev.2022.104718] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 12/14/2022]
Abstract
Adequate oxygen supply is essential for the human brain to meet its high energy demands. Therefore, elaborate molecular and systemic mechanism are in place to enable adaptation to low oxygen availability. Anxiety and depressive disorders are characterized by alterations in brain oxygen metabolism and of its components, such as mitochondria or hypoxia inducible factor (HIF)-pathways. Conversely, sensitivity and tolerance to hypoxia may depend on parameters of mental stress and the severity of anxiety and depressive disorders. Here we discuss relevant mechanisms of adaptations to hypoxia, as well as their involvement in mental stress and the etiopathogenesis of anxiety and depressive disorders. We suggest that mechanisms of adaptations to hypoxia (including metabolic responses, inflammation, and the activation of chemosensitive brain regions) modulate and are modulated by stress-related pathways and associated psychiatric diseases. While severe chronic hypoxia or dysfunctional hypoxia adaptations can contribute to the pathogenesis of anxiety and depressive disorders, harnessing controlled responses to hypoxia to increase cellular and psychological resilience emerges as a novel treatment strategy for these diseases.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Martin Niedermeier
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Clinic for Psychiatry II, Innsbruck Medical University, Innsbruck, Austria
| | - Erwin van den Burg
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Kopp
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Ron Stoop
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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2
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Myers DA, Singleton K, Hyatt K, Kaushal KM, Ducsay CA. Long term hypoxia during gestation alters perirenal adipose tissue gene expression in the lamb. Adipocyte 2020; 9:223-233. [PMID: 32403966 PMCID: PMC7238872 DOI: 10.1080/21623945.2020.1763726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We previously reported that following long-term hypoxia (LTH), the ovine foetus exhibits enhanced expression of brown/beige adipose genes. This study was designed to determine if these changes are preserved after birth. Pregnant ewes were divided among three groups, 1) Control, sea level, 2) LTH, high altitude (3,820 m, LTH-HA) from ~ day 40 of gestation through ~14 days post-delivery and 3) LTH from ⁓ day 40 through day 137 of gestation then returned to the laboratory where atory reduced maternal PO2 was maintained by nitrogen infusion. Following delivery, lambs remained at sea level (LTH-SL). Perirenal adipose tissue was collected at ~day 14, and qRT-PCR was used to quantify mRNA. Uncoupling protein 1 (UCP-1), PPAR gamma coactivator 1 (PGC1α), and deiodinase-2 (DIO2) mRNA levels were significantly lower in both LTH groups while PR domain containing 16 (PRDM16) levels did not differ. Peroxisome proliferator-activated receptor (PPARγ) was maintained in the LTH-HA group and significantly increased in the LTH-SL group, compared to control. Unlike our previous LTH foetal studies, the brown/beige fat phenotype was rapidly lost by day 14 postpartum compared to control, while PPARγ was maintained. This loss of the brown fat phenotype may promote obesity due to decreased energy expenditure, favouring fat deposition.
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Affiliation(s)
- Dean A. Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Krista Singleton
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kim Hyatt
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kanchan M. Kaushal
- Lawrence D. Longo M.D. Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Charles A. Ducsay
- Lawrence D. Longo M.D. Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
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3
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Kouroupi M, Sivridis E, Papazoglou D, Koukourakis MI, Giatromanolaki A. Hypoxia Inducible Factor Expression and Angiogenesis - Analysis in the Pituitary Gland and Patterns of Death. ACTA ACUST UNITED AC 2018; 32:185-190. [PMID: 29275318 DOI: 10.21873/invivo.11223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 01/31/2023]
Abstract
BACKGROUND/AIM We investigated the expression of angiogenesis and hypoxia markers in the adenohypophysis and neurohypophysis of patients who died from various acute or chronic diseases. MATERIALS AND METHODS Paraffin-embedded material of pituitary glands (97 patients) was investigated immunohistochemically for vascular density (CD31) and the expression of vascular endothelial growth factor (VEGF) and of hypoxia inducible factors HIF1α and HIF2α. RESULTS Vascular density, and HIF1α/HIF2α reactivity is directly related with VEGF expression in the pituitary gland, suggesting that the HIF pathway may regulate the vascular density and blood flow in the gland under hypoxic conditions. HIF2α appears to be a key regulator in neurohypophysis, whilst in adenohypophysis HIF1α and HIF2α are equally expressed. Chronic conditions, including alcoholism and substance abuse, seem to activate the HIF pathway in both neuro- and adeno-hypophysis. CONCLUSION The HIF pathway has an important role in regulating vascular density and blood flow in the pituitary gland.
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Affiliation(s)
- Maria Kouroupi
- Department of Pathology, University General Hospital of Alexandroupolis/Democritus University of Thrace, Alexandroupolis, Greece
| | - Efthimios Sivridis
- Department of Pathology, University General Hospital of Alexandroupolis/Democritus University of Thrace, Alexandroupolis, Greece
| | - Dimitrios Papazoglou
- Department of Internal Medicine, University General Hospital of Alexandroupolis/Democritus University of Thrace, Alexandroupolis, Greece
| | - Michael I Koukourakis
- Department of Radiotherapy/Oncology, University General Hospital of Alexandroupolis/Democritus University of Thrace, Alexandroupolis, Greece
| | - Alexandra Giatromanolaki
- Department of Pathology, University General Hospital of Alexandroupolis/Democritus University of Thrace, Alexandroupolis, Greece
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Ducsay CA, Goyal R, Pearce WJ, Wilson S, Hu XQ, Zhang L. Gestational Hypoxia and Developmental Plasticity. Physiol Rev 2018; 98:1241-1334. [PMID: 29717932 PMCID: PMC6088145 DOI: 10.1152/physrev.00043.2017] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.
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Affiliation(s)
- Charles A. Ducsay
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Ravi Goyal
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - William J. Pearce
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Sean Wilson
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Xiang-Qun Hu
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Lubo Zhang
- The Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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5
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Itani N, Salinas CE, Villena M, Skeffington KL, Beck C, Villamor E, Blanco CE, Giussani DA. The highs and lows of programmed cardiovascular disease by developmental hypoxia: studies in the chicken embryo. J Physiol 2017; 596:2991-3006. [PMID: 28983923 DOI: 10.1113/jp274111] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
It is now established that adverse conditions during pregnancy can trigger a fetal origin of cardiovascular dysfunction and/or increase the risk of heart disease in later life. Suboptimal environmental conditions during early life that may promote the development of cardiovascular dysfunction in the offspring include alterations in fetal oxygenation and nutrition as well as fetal exposure to stress hormones, such as glucocorticoids. There has been growing interest in identifying the partial contributions of each of these stressors to programming of cardiovascular dysfunction. However, in humans and in many animal models this is difficult, as the challenges cannot be disentangled. By using the chicken embryo as an animal model, science has been able to circumvent a number of problems. In contrast to mammals, in the chicken embryo the effects on the developing cardiovascular system of changes in oxygenation, nutrition or stress hormones can be isolated and determined directly, independent of changes in the maternal or placental physiology. In this review, we summarise studies that have exploited the chicken embryo model to determine the effects on prenatal growth, cardiovascular development and pituitary-adrenal function of isolated chronic developmental hypoxia.
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Affiliation(s)
- N Itani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.,Cambridge Cardiovascular Strategic Research Initiative, Division of Cardiovascular Medicine, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - C E Salinas
- Instituto Boliviano de Biología de Altura, Facultad de Medicina, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - M Villena
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - K L Skeffington
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - C Beck
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - E Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Universiteitssingel 40, 6229, ER Maastricht, The Netherlands
| | - C E Blanco
- Department of Neonatology, The National Maternity Hospital, Holles Street, Dublin, D02 YH21, Ireland
| | - D A Giussani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.,Cambridge Cardiovascular Strategic Research Initiative, Division of Cardiovascular Medicine, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
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6
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Vargas VE, Gurung S, Grant B, Hyatt K, Singleton K, Myers SM, Saunders D, Njoku C, Towner R, Myers DA. Gestational hypoxia disrupts the neonatal leptin surge and programs hyperphagia and obesity in male offspring in the Sprague-Dawley rat. PLoS One 2017; 12:e0185272. [PMID: 28957383 PMCID: PMC5619766 DOI: 10.1371/journal.pone.0185272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 09/08/2017] [Indexed: 12/04/2022] Open
Abstract
The effect of gestational hypoxia on the neonatal leptin surge, development of hypothalamic arcuate nuclei (ARH) projections and appetite that could contribute to the programming of offspring obesity is lacking. We examined the effect of 12% O2 from gestational days 15–19 in the Sprague-Dawley rat on post-weaning appetite, fat deposition by MRI, adipose tissue cytokine expression, the neonatal leptin surge, ARH response to exogenous leptin, and αMSH projections to the paraventricular nucleus (PVN) in response to a high fat (HFD) or control diet (CD) in male offspring. Normoxia (NMX) and Hypoxia (HPX) offspring exhibited increased food intake when fed a HFD from 5–8 weeks post-birth; HPX offspring on the CD had increased food intake from weeks 5–7 vs. NMX offspring on a CD. HPX offspring on a HFD remained hyperphagic through 23 weeks. Body weight were the same between offspring from HPX vs. NMX dams from 4–12 weeks of age fed a CD or HFD. By 14–23 weeks of age, HPX offspring fed the CD or HFD as well as male NMX offspring fed the HFD were heavier vs. NMX offspring fed the CD. HPX offspring fed a CD exhibited increased abdominal adiposity (MRI) that was amplified by a HFD. HPX offspring fed a HFD exhibited the highest abdominal fat cytokine expression. HPX male offspring had higher plasma leptin from postnatal day (PN) 6 through 14 vs. NMX pups. HPX offspring exhibited increased basal c-Fos labeled cells in the ARH vs. NMX pups on PN16. Leptin increased c-Fos staining in the ARH in NMX but not HPX offspring at PN16. HPX offspring had fewer αMSH fibers in the PVN vs. NMX offspring on PN16. In conclusion, gestational hypoxia impacts the developing ARH resulting in hyperphagia contributing to adult obesity on a control diet and exacerbated by a HFD.
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Affiliation(s)
- Vladimir E. Vargas
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Sunam Gurung
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Benjamin Grant
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Kimberly Hyatt
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Krista Singleton
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Sarah M. Myers
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Debra Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Charity Njoku
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Dean A. Myers
- Departments of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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7
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Vargas VE, Myers DA, Kaushal KM, Ducsay CA. Expression of StAR and Key Genes Regulating Cortisol Biosynthesis in Near Term Ovine Fetal Adrenocortical Cells: Effects of Long-Term Hypoxia. Reprod Sci 2017; 25:230-238. [PMID: 28468567 DOI: 10.1177/1933719117707056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously demonstrated decreased expression of key genes regulating cortisol biosynthesis in long-term hypoxic (LTH) sheep fetal adrenals compared to controls. We also showed that inhibition of the extracellular signal-regulated kinases (ERKs) with the mitogen-activated protein kinase (MEK)/ERK inhibitor UO126 limited adrenocorticotropic (ACTH)-induced cortisol production in ovine fetal adrenocortical cells (FACs), suggesting a role for ERKs in cortisol synthesis. This study was designed to determine whether the previously observed decrease in LTH cytochrome P45011A1/cytochrome P450c17 (CYP11A1/CYP17) in adrenal glands was maintained in vitro, and whether ACTH alone with or without UO126 treatment had altered the expression of CYP11A1, CYP17, and steroidogenic acute regulatory protein (StAR) in control versus LTH FACs. Ewes were maintained at high altitude (3820 m) from ∼40 days of gestation (dG). At 138 to 141 dG, fetal adrenal glands were collected from LTH (n = 5) and age-matched normoxic controls (n = 6). Fetal adrenocortical cells were challenged with ACTH (10-8 M) with or without UO126 (10 µM) for 18 hours. Media samples were collected for cortisol analysis and messenger RNA (mRNA) for CYP11A1, CYP17, and StAR was quantified by quantitative real-time polymerase chain reaction. Cortisol was higher in the LTH versus control ( P < .05). StAR mRNA was decreased in LTH versus control ( P < .05). U0126 alone had no effect on mRNA in either group. UO126 prevented the increase in CYP11A1 and CYP17 in control FACs. Basal CYP11A1 and CYP17 were not different in LTH versus control. ACTH increased CYP11A1 and CYP17 only in control FACs ( P < .05). U1026 attenuated the ACTH response indicative of a role for ERK in CYP11A1 and CYP17 expression. ACTH may require additional factors in FACs to fully regulate StAR expression.
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Affiliation(s)
- Vladimir E Vargas
- 1 Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA.,2 Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Dean A Myers
- 2 Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kanchan M Kaushal
- 1 Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Charles A Ducsay
- 1 Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA
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8
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Multiple beneficial effects of melanocortin MC 4 receptor agonists in experimental neurodegenerative disorders: Therapeutic perspectives. Prog Neurobiol 2016; 148:40-56. [PMID: 27916623 DOI: 10.1016/j.pneurobio.2016.11.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 11/22/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
Melanocortin peptides induce neuroprotection in acute and chronic experimental neurodegenerative conditions. Melanocortins likewise counteract systemic responses to brain injuries. Furthermore, they promote neurogenesis by activating critical signaling pathways. Melanocortin-induced long-lasting improvement in synaptic activity and neurological performance, including learning and memory, sensory-motor orientation and coordinated limb use, has been consistently observed in experimental models of acute and chronic neurodegeneration. Evidence indicates that the neuroprotective and neurogenic effects of melanocortins, as well as the protection against systemic responses to a brain injury, are mediated by brain melanocortin 4 (MC4) receptors, through an involvement of the vagus nerve. Here we discuss the targets and mechanisms underlying the multiple beneficial effects recently observed in animal models of neurodegeneration. We comment on the potential clinical usefulness of melanocortin MC4 receptor agonists as neuroprotective and neuroregenerative agents in ischemic stroke, subarachnoid hemorrhage, traumatic brain injury, spinal cord injury, and Alzheimer's disease.
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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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Myers DA, Singleton K, Kenkel C, Kaushal KM, Ducsay CA. Gestational hypoxia modulates expression of corticotropin-releasing hormone and arginine vasopressin in the paraventricular nucleus in the ovine fetus. Physiol Rep 2016; 4:e12643. [PMID: 26733242 PMCID: PMC4760403 DOI: 10.14814/phy2.12643] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 11/24/2022] Open
Abstract
Maturation of the fetal hypothalamo-pituitary-adrenocortical (HPA) axis is critical for organ maturation necessary for the fetus to transition to the ex-utero environment. Intrauterine stressors can hasten maturation of the HPA axis leading to fetal growth restriction and in sheep, premature birth. We have previously reported that high-altitude mediated, long-term-moderate gestational hypoxia (LTH) during gestation has a significant impact on the fetal HPA axis. Significant effects were observed at the level of both the anterior pituitary and adrenal cortex resulting in elevated plasma ACTH during late gestation with decreased adrenocortical expression of enzymes rate limiting for cortisol synthesis. As such, these fetuses exhibited the normal ontogenic rise in fetal plasma cortisol but an exaggerated cortisol response to acute stress. This study extended these findings to ACTH secretagogue expression in the PVN using in situ hybridization. We report that the expression of AVP but not CRH was increased in the medial parvocellular PVN (mpPVN) in the LTH fetus. This represented an increase in both AVP mRNA per neuron as well as an increase in AVP hybridizing neurons with no increase in mpPVN CRH neurons. LTH had no effect on PVN volume, area of CRH or AVP hybridization, thus LTH did not have a trophic effect on the size of the nucleus. In conclusion, there appears to be a switch from CRH to AVP as a primary ACTH secretagogue in response to LTH, supporting our previous findings of increased anterior pituitary sensitivity to AVP over CRH in the LTH fetus.
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Affiliation(s)
- Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Krista Singleton
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Christy Kenkel
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Kanchan M Kaushal
- School of Medicine, The Center for Perinatal Biology Loma Linda University, Loma Linda, California
| | - Charles A Ducsay
- School of Medicine, The Center for Perinatal Biology Loma Linda University, Loma Linda, California
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11
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Newby EA, Myers DA, Ducsay CA. Fetal endocrine and metabolic adaptations to hypoxia: the role of the hypothalamic-pituitary-adrenal axis. Am J Physiol Endocrinol Metab 2015; 309:E429-39. [PMID: 26173460 PMCID: PMC4556885 DOI: 10.1152/ajpendo.00126.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/10/2015] [Indexed: 11/22/2022]
Abstract
In utero, hypoxia is a significant yet common stress that perturbs homeostasis and can occur due to preeclampsia, preterm labor, maternal smoking, heart or lung disease, obesity, and high altitude. The fetus has the extraordinary capacity to respond to stress during development. This is mediated in part by the hypothalamic-pituitary-adrenal (HPA) axis and more recently explored changes in perirenal adipose tissue (PAT) in response to hypoxia. Obvious ethical considerations limit studies of the human fetus, and fetal studies in the rodent model are limited due to size considerations and major differences in developmental landmarks. The sheep is a common model that has been used extensively to study the effects of both acute and chronic hypoxia on fetal development. In response to high-altitude-induced, moderate long-term hypoxia (LTH), both the HPA axis and PAT adapt to preserve normal fetal growth and development while allowing for responses to acute stress. Although these adaptations appear beneficial during fetal development, they may become deleterious postnatally and into adulthood. The goal of this review is to examine the role of the HPA axis in the convergence of endocrine and metabolic adaptive responses to hypoxia in the fetus.
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Affiliation(s)
- Elizabeth A Newby
- Center for Perinatal Biology, Loma Linda University, Loma Linda, California; and
| | - Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University, Loma Linda, California; and
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12
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Newby EA, Kaushal KM, Myers DA, Ducsay CA. Adrenocorticotropic Hormone and PI3K/Akt Inhibition Reduce eNOS Phosphorylation and Increase Cortisol Biosynthesis in Long-Term Hypoxic Ovine Fetal Adrenal Cortical Cells. Reprod Sci 2015; 22:932-41. [PMID: 25656500 DOI: 10.1177/1933719115570899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This study was designed to determine the role of the MEK/ERK1/2 and PI3K/Akt pathways in cortisol production and endothelial nitric oxide synthase (eNOS) phosphorylation (peNOS) in the ovine fetal adrenal in response to long-term hypoxia (LTH). Pregnant ewes were maintained at high altitude (3820 m) for the last 100 days of gestation (dGa). At 138 to 142 dGa, fetal adrenal cortical cells (FACs) were collected from LTH and age-matched normoxic fetuses. Cortisol production and peNOS were measured in response to pretreatment with the MEK/ERK1/2 pathway inhibitor UO126 (UO) and adrenocorticotropic hormone (ACTH) stimulation. UO126 reduced ACTH-stimulated cortisol in both normoxic and LTH FACs. UO126 alone or in combination with ACTH reduced peNOS in the normoxic group, while ACTH alone or ACTH + UO inhibited peNOS in LTH FACs. Additionally, cortisol was measured in response to pretreatment with UO and treatment with 22R-hydroxycholesterol (22R-OHC) or water-soluble cholesterol (WSC) with and without ACTH stimulation. UO126 had no effect on 22R-OHC-treated cells, but reduced cortisol in cells treated with WSC and/or ACTH. Cortisol and peNOS were also measured in response to pretreatment with PI3K/Akt pathway inhibitor Wortmannin (WT) and ACTH stimulation. Wortmannin further increased cortisol under ACTH-stimulated conditions and, like ACTH, reduced peNOS in LTH but not normoxic FACs. Together, these data suggest that in LTH FACs MEK/ERK1/2 does not regulate peNOS but that UO acts downstream from eNOS, possibly at cholesterol transport, to affect cortisol production in LTH FACs, while the PI3K/Akt pathway, along with ACTH, regulates peNOS and plays a role in the fetal adaptation to LTH in FACs.
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Affiliation(s)
- Elizabeth A Newby
- Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA
| | - Kanchan M Kaushal
- Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA
| | - Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University, Loma Linda, CA, USA
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Myers DA, Singleton K, Hyatt K, Mlynarczyk M, Kaushal KM, Ducsay CA. Long-Term Gestational Hypoxia Modulates Expression of Key Genes Governing Mitochondrial Function in the Perirenal Adipose of the Late Gestation Sheep Fetus. Reprod Sci 2014; 22:654-63. [PMID: 25504105 DOI: 10.1177/1933719114561554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously reported that long-term hypoxia (LTH) increases expression of brown adipose tissue (BAT) genes in the perirenal adipose in the ovine fetus. The mechanisms with which hypoxia mediates the enhanced BAT phenotype are unresolved. This study was designed to examine the effects of LTH on (1) the expression of endothelial cell nitric oxide synthase (eNOS) and (2) indicators of mitochondrial biogenesis (transcription factors mitochondrial transcription factor A (mtTFA), nuclear respiratory factor (NRF) 1, and NRF-2; cytochrome c oxidase (COX) I, II, and IV and mitochondrial DNA content). Pregnant ewes were maintained at high altitude (3820 m) from ∼40 to 137 to 140 days of gestation and perirenal adipose was collected from normoxic control and LTH fetuses. There was no effect of LTH on fetal body weight or perirenal adipose mass. Long-term hypoxia increased (P < .05) perirenal eNOS and phospho-eNOS, messenger RNA (mRNA) for NRF1, NRF-2, mtTFA as well as COX-I, COX-II, and COX-IV mRNA. In contrast, mRNA for 2 markers for cellular proliferation (Ki67 and proliferating cell nuclear antigen [PCNA]) was lower in perirenal adipose from LTH fetuses compared to controls (P < .05), while mitochondrial to nuclear DNA ratio did not differ between groups. In conclusion, nitric oxide may function as a mechanism via which LTH enhances the BAT phenotype in fetal sheep prior to birth. Although there is an apparent increase in genes supporting mitochondrial function and adaptive thermogenesis in response to LTH, there does not appear to be an increased mitochondrial biogenesis per se. Such adaptive changes may provide a mechanism for the prominence of the BAT phenotype observed in the late gestation LTH fetus.
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Affiliation(s)
- Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Krista Singleton
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kim Hyatt
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Malgorzata Mlynarczyk
- Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA
| | - Kanchan M Kaushal
- Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA
| | - Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA
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Altitude, Attitude and Adaptation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 814:147-57. [DOI: 10.1007/978-1-4939-1031-1_13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Maternal undernutrition during the first week after conception results in decreased expression of glucocorticoid receptor mRNA in the absence of GR exon 17 hypermethylation in the fetal pituitary in late gestation. J Dev Orig Health Dis 2013; 4:391-401. [DOI: 10.1017/s2040174413000378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Exposure to maternal undernutrition during the periconceptional period results in an earlier prepartum activation of the fetal hypothalamo–pituitary–adrenal (HPA) axis and altered stress responsiveness in the offspring. It is not known whether such changes are a consequence of exposure of the oocyte and/or the early embryo to maternal undernutrition in the periconceptional period. We have compared the effects of ‘periconceptional’ undernutrition (PCUN: maternal undernutrition imposed from at least 45 days before until 6 days after conception), and ‘early preimplantation’ undernutrition (PIUN: maternal undernutrition imposed for only 6 days after conception) on the expression of genes in the fetal anterior pituitary that regulate adrenal growth and steroidogenesis, proopiomelanorcortin (POMC), prohormone convertase 1 (PC1), 11β-hydroxysteroid dehydrogenase type 1 and 2 (11βHSD1 and 2) and the glucocorticoid receptor (GR) in fetal sheep at 136–138 days of gestation. Pituitary GR mRNA expression was significantly lower in the PCUN and PIUN groups in both singletons and twins compared with controls, although this suppression of GR expression was not associated with hypermethylation of the exon 17 region of the GR gene. In twin fetuses, the pituitary 11βHSD1 mRNA expression was significantly higher in the PIUN group compared with the PCUN but not the control group. Thus, exposure of the single or twin embryo to maternal undernutrition for only 1 week after conception is sufficient to cause a suppression of the pituitary GR expression in late gestation. These changes may contribute to the increased stress responsiveness of the HPA axis in the offspring after exposure to poor nutrition during the periconceptional period.
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Vargas VE, Kaushal KM, Monau TR, Myers DA, Ducsay CA. Extracellular signal-regulated kinases (ERK1/2) signaling pathway plays a role in cortisol secretion in the long-term hypoxic ovine fetal adrenal near term. Am J Physiol Regul Integr Comp Physiol 2013; 304:R636-43. [PMID: 23427082 DOI: 10.1152/ajpregu.00318.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study assessed the role of the extracellular signal-regulated kinase (ERK) signaling pathway on the previously observed enhanced cortisol secretion in response to adrenocorticotropic hormone (ACTH) treatment in fetal adrenocortical cells (FACs) from long-term hypoxic (LTH) ovine fetuses. Ewes were maintained at high altitude (3,820 m) from ~40 to 138-141 days gestation when FACs were collected and challenged with either ACTH (10 nM) or 8-bromoadenosine 3',5'-cyclic monophosphate (8-bromo-cAMP, 10 mM) in the presence or absence of the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MEK)/ERK inhibitor UO126 (10 μM). FACs from age-matched normoxic fetuses served as controls. Media and FACs were collected at selected time intervals after ACTH or 8-bromo-cAMP stimulation for cortisol measurement and Western analysis of ERK1/2 and phospho-ERK1 and -2 (pERK1/2). After ACTH or 8-bromo-cAMP treatment, cortisol production was greater in the LTH group compared with control (P < 0.05). UO126 reduced ACTH and 8-bromo-cAMP-mediated cortisol output in both groups (P < 0.01 vs. ACTH or 8-bromo-cAMP alone). Under basal conditions, ERK1/2 and pERK1/2 were not different between LTH and normoxic fetuses. In response to ACTH or 8-bromo-cAMP treatment, ERK1/2 were not different between groups; however, pERK1/2 were elevated in the LTH FACs compared with normoxic control FACs. ERK1/2 phosphorylation declined following ACTH treatment in the control group, but UO126 had no effect on ERK1/2 compared with untreated levels. Both ACTH and 8-bromo-cAMP treatment resulted in a decline of protein levels. UO126 pretreatment virtually eliminated pERK1/2 expression. We conclude that basal ERK signaling in FACs is necessary for normal cortisol production and sustained pERK in LTH adrenals enhances cortisol production.
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Affiliation(s)
- Vladimir E Vargas
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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Ducsay CA, Furuta K, Vargas VE, Kaushal KM, Singleton K, Hyatt K, Myers DA. Leptin receptor antagonist treatment ameliorates the effects of long-term maternal hypoxia on adrenal expression of key steroidogenic genes in the ovine fetus. Am J Physiol Regul Integr Comp Physiol 2013; 304:R435-42. [PMID: 23344230 DOI: 10.1152/ajpregu.00377.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported elevated adipose leptin expression, plasma leptin concentrations, and adrenocortical leptin receptor expression in the long-term hypoxic (LTH) ovine fetus. This study addressed whether leptin antagonist (LA) administration to LTH fetal sheep altered expression of key genes governing cortisol synthesis. Ewes were maintained at high altitude (3,820 meters) from 40 to 130 days gestation (dG), returned to Loma Linda University, and implanted with a maternal tracheal catheter. Reduced Po2 was maintained by nitrogen infusion. On 132 dG, LTH (n = 11) and age-matched, normoxic control (n = 11) fetuses underwent vascular catheter implantation. At 138 dG, fetuses were continuously infused with either saline or the LA (1.5 mg·kg(-1)·day(-1)) for 4 days and samples collected for blood gases, ACTH, and cortisol. Fetal adrenal cortex was collected for determination of steriodogenic acute regulatory protein (StAR), ACTH, and leptin receptor, cholesterol side-chain cleavage (CYP11A1), cytochrome P-450 11β-hydroxylase (CYP11B1), 17α-hydroxylase (CYP17), 21-hydroxylase (CYP21), signal transducer and activator of transcription 3 (STAT3), pSTAT3, and 17β-hydroxysteroid dehydrogenase (HSD3B) expression. In the saline-infused LTH fetuses, StAR, ACTH receptor, CYP11A1, and CYP17 expression was significantly lower compared with control (P < 0.05), whereas levels of CYP11B1, CYP21, and HSD3B mRNA were similar between groups. LA infusion restored expression of StAR, pSTAT3, CYP11A1, and CYP17, but not ACTH receptor, to normal ontogenic levels in the LTH group while having no effect on control fetuses. Neither fetal plasma ACTH nor cortisol concentrations were altered by LA infusion. We speculate that while leptin plays a role in governing expression of key enzymes and StAR in response to LTH, other factors play a role in modulating cortisol synthesis in these fetuses.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
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Adrenocortical and adipose responses to high-altitude-induced, long-term hypoxia in the ovine fetus. J Pregnancy 2012; 2012:681306. [PMID: 22666594 PMCID: PMC3361245 DOI: 10.1155/2012/681306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/02/2012] [Indexed: 11/17/2022] Open
Abstract
By late gestation, the maturing hypothalamo-pituitary-adrenal (HPA) axis aids the fetus in responding to stress. Hypoxia represents a significant threat to the fetus accompanying situations such as preeclampsia, smoking, high altitude, and preterm labor. We developed a model of high-altitude (3,820 m), long-term hypoxia (LTH) in pregnant sheep. We describe the impact of LTH on the fetal HPA axis at the level of the hypothalamic paraventricular nucleus (PVN), anterior pituitary corticotrope, and adrenal cortex. At the PVN and anterior pituitary, the responses to LTH are consistent with hypoxia being a potent activator of the HPA axis and potentially maladaptive, while the adrenocortical response to LTH appears to be primarily adaptive. We discuss mechanisms involved in the delicate balance between these seemingly opposing responses that preserve the normal ontogenic rise in fetal plasma cortisol essential for organ maturation and in this species, birth. Further, we examine the response to, and ramifications of, an acute secondary stressor in the LTH fetus. We provide an integrative model on the potential role of adipose in modulating these responses to LTH. Integration of these adaptive responses to LTH plays a key role in promoting normal fetal growth and development under conditions of a chronic stress.
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Su Y, Carey LC, Rose JC, Pulgar VM. Leptin alters adrenal responsiveness by decreasing expression of ACTH-R, StAR, and P450c21 in hypoxemic fetal sheep. Reprod Sci 2012; 19:1075-84. [PMID: 22534336 DOI: 10.1177/1933719112442246] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The late gestation increase in adrenal responsiveness to adrenocorticotropin (ACTH) is dependent upon the upregulation of the ACTH receptor (ACTH-R), steroidogenic acute regulatory protein (StAR), and steroidogenic enzymes in the fetal adrenal. Long-term hypoxia decreases the expression of these and adrenal responsiveness to ACTH in vivo. Leptin, an adipocyte-derived hormone which attenuates the peripartum increase in fetal plasma cortisol is elevated in hypoxic fetuses. Therefore, we hypothesized that increases in plasma leptin will inhibit the expression of the ACTH-R, StAR, and steroidogenic enzymes and attenuate adrenal responsiveness in hypoxic fetuses. Spontaneously hypoxemic fetal sheep (132 days of gestation, PO(2) ≈ 15 mm Hg) were infused with recombinant human leptin (n = 8) or saline (n = 7) for 96 hours. An ACTH challenge was performed at 72 hours of infusion to assess adrenal responsiveness. Plasma cortisol and ACTH were measured daily and adrenals were collected after 96 hours infusion for messenger RNA (mRNA) and protein expression measurement. Plasma cortisol concentrations were lower in leptin- compared with saline-infused fetuses (14.8 ± 3.2 vs 42.3 ± 9.6 ng/mL, P < .05), as was the cortisol:ACTH ratio (0.9 ± 0.074 vs 46 ± 1.49, P < .05). Increases in cortisol concentrations were blunted in the leptin-treated group after ACTH(1-24) challenge (F = 12.2, P < .0001). Adrenal ACTH-R, StAR, and P450c21 expression levels were reduced in leptin-treated fetuses (P < .05), whereas the expression of Ob-Ra and Ob-Rb leptin receptor isoforms remained unchanged. Our results indicate that leptin blunts adrenal responsiveness in the late gestation hypoxemic fetus, and this effect appears mediated by decreased adrenal ACTH-R, StAR, and P450c21 expression.
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Affiliation(s)
- Yixin Su
- Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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Giuliani D, Minutoli L, Ottani A, Spaccapelo L, Bitto A, Galantucci M, Altavilla D, Squadrito F, Guarini S. Melanocortins as potential therapeutic agents in severe hypoxic conditions. Front Neuroendocrinol 2012; 33:179-93. [PMID: 22531139 DOI: 10.1016/j.yfrne.2012.04.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/26/2012] [Accepted: 04/09/2012] [Indexed: 01/14/2023]
Abstract
Melanocortin peptides with the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) sequences and synthetic analogs have protective and life-saving effects in experimental conditions of circulatory shock, myocardial ischemia, ischemic stroke, traumatic brain injury, respiratory arrest, renal ischemia, intestinal ischemia and testicular ischemia, as well as in experimental heart transplantation. Moreover, melanocortins improve functional recovery and stimulate neurogenesis in experimental models of cerebral ischemia. These beneficial effects of ACTH/MSH-like peptides are mostly mediated by brain melanocortin MC(3)/MC(4) receptors, whose activation triggers protective pathways that counteract the main ischemia/reperfusion-related mechanisms of damage. Induction of signaling pathways and other molecular regulators of neural stem/progenitor cell proliferation, differentiation and integration seems to be the key mechanism of neurogenesis stimulation. Synthesis of stable and highly selective agonists at MC(3) and MC(4) receptors could provide the potential for development of a new class of drugs for a novel approach to management of severe ischemic diseases.
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Affiliation(s)
- Daniela Giuliani
- Department of Biomedical Sciences, Section of Pharmacology, University of Modena and Reggio Emilia, 41125 Modena, Italy
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Roberson AE, Hyatt K, Kenkel C, Hanson K, Myers DA. Interleukin 1β Regulates Progesterone Metabolism in Human Cervical Fibroblasts. Reprod Sci 2011; 19:271-81. [DOI: 10.1177/1933719111419246] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Amy E. Roberson
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kimberly Hyatt
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Christy Kenkel
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Krista Hanson
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Dean A. Myers
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Ducsay CA, Myers DA. eNOS activation and NO function: differential control of steroidogenesis by nitric oxide and its adaptation with hypoxia. J Endocrinol 2011; 210:259-69. [PMID: 21653733 DOI: 10.1530/joe-11-0034] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nitric oxide (NO) plays a role in a wide range of physiological processes. Aside from its widely studied function in the regulation of vascular function, NO has been shown to impact steroidogenesis in a number of different tissues. The goal of this review is to explore the effects of NO on steroid production and further, to discern its source(s) and mechanism of action. Attention will be given to the regulation of NO synthases in specific endocrine tissues including ovaries, testes, and adrenal glands. The effects of hypoxia on generation of NO and subsequent effects on steroid biosynthesis will also be examined. Finally, a potential model for the interaction of hypoxia on NO synthesis and steroid production is proposed.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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Salinas CE, Villena M, Blanco CE, Giussani DA. Adrenocortical suppression in highland chick embryos is restored during incubation at sea level. High Alt Med Biol 2011; 12:79-87. [PMID: 21452969 DOI: 10.1089/ham.2010.1040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
By combining the chick embryo model with incubation at high altitude, this study tested the hypothesis that development at high altitude is related to a fetal origin of adrenocortical but not adrenomedullary suppression and that hypoxia is the mechanism underlying the relationship. Fertilized eggs from sea-level or high altitude hens were incubated at sea level or high altitude. Fertilized eggs from sea-level hens were also incubated at altitude with oxygen supplementation. At day 20 of incubation, embryonic blood was taken for measurement of plasma corticotropin, corticosterone, and Po(2). Following biometry, the adrenal glands were collected and frozen for measurement of catecholamine content. Development of chick embryos at high altitude led to pronounced adrenocortical blunting, but an increase in adrenal catecholamine content. These effects were similar whether the fertilized eggs were laid by sea-level or high altitude hens. The effects of high altitude on the stress axes were completely prevented by incubation at high altitude with oxygen supplementation. When chick embryos from high altitude hens were incubated at sea level, plasma hormones and adrenal catecholamine content were partially restored toward levels measured in sea-level chick embryos. There was a significant correlation between adrenocortical blunting and elevated adrenal catecholamine content with both asymmetric growth restriction and fetal hypoxia. The data support the hypothesis tested and provide evidence to isolate the direct contribution of developmental hypoxia to alterations in the stress system.
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Affiliation(s)
- Carlos E Salinas
- Instituto Boliviano de Biología de Altura, Facultad de Medicina, Universidad Mayor de San Andrés, La Paz, Bolivia
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Roulin A, Ducrest AL. Association between melanism, physiology and behaviour: A role for the melanocortin system. Eur J Pharmacol 2011; 660:226-33. [DOI: 10.1016/j.ejphar.2011.01.036] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/22/2010] [Accepted: 01/13/2011] [Indexed: 11/26/2022]
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25
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Pale and dark reddish melanic tawny owls differentially regulate the level of blood circulating POMC prohormone in relation to environmental conditions. Oecologia 2011; 166:913-21. [DOI: 10.1007/s00442-011-1955-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
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Winikor J, Schlaerth C, Rabaglino MB, Cousins R, Sutherland M, Wood CE. Complex actions of estradiol-3-sulfate in late gestation fetal brain. Reprod Sci 2011; 18:654-65. [PMID: 21273638 DOI: 10.1177/1933719110395400] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The most abundant form of estrogen circulating in fetal plasma is sulfo-conjugated estrogen; for example, estradiol-3-sulfate (E(2)SO(4)) is more highly abundant than estradiol (E(2)). The present study investigated the ontogeny of the deconjugating (steroid sulfatase [STS]) and conjugating (estrogen sulfotransferase [STF]) enzymes in ovine fetal brain and tested the hypothesis that treatment with E(2)SO(4) would alter the expression of one or both enzymes. Steroid sulfatase was more highly expressed than STF, and both changed as a function of gestational age. Estradiol-3-sulfate infused intracerebroventricularly (icv) significantly increased plasma adrenocorticotropic hormone (ACTH) and cortisol concentrations. Plasma E(2) and E(2)SO(4) were increased, and brain expression of estrogen receptor α was decreased. The proteins STS and STF were up- and downregulated, respectively. Pituitary proopiomelanocortin (POMC) and follicle-stimulating hormone (FSH) and hypothalamic corticotrophin-releasing hormone (CRH) messenger RNA (mRNA) was decreased. We conclude that E(2)SO(4) has complex actions on the fetal brain, which might involve deconjugation by STS, but that the net result of direct E(2)SO(4) icv infusion is more complex than can be accounted for by infusion of E(2) alone.
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Affiliation(s)
- Jared Winikor
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, FL, USA
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27
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Vargas VE, Kaushal KM, Monau T, Myers DA, Ducsay CA. Long-term hypoxia enhances cortisol biosynthesis in near-term ovine fetal adrenal cortical cells. Reprod Sci 2010; 18:277-85. [PMID: 21079237 DOI: 10.1177/1933719110386242] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study was designed to determine the potential mechanism/mechanisms of previously observed enhanced fetal cortisol secretion following exposure to long-term hypoxia (LTH). Pregnant ewes were maintained at high altitude (3820 m) for approximately the last 100 days of gestation. Between the gestation days of 138 and 141, adrenal glands were collected from LTH and age-matched normoxic control fetuses. Cyclic adenosine monophosphate (cAMP), cortisol, and steroidogenic acute regulatory (StAR) protein were measured in response to adrenocorticotropic hormone (ACTH) stimulation. Cortisol responses to ACTH were also measured in the presence of the protein kinase (PKA) inhibitor H-89, proopiomelanocortin (POMC), or 22-kDa pro-ACTH. Cortisol output was higher in the LTH group compared to the control (P < .05), following ACTH treatment while the cAMP response was similar in both groups. Although PKA inhibition decreased cortisol production in both groups, however no differences were observed between groups. Western analysis revealed a significant increase in protein expression for StAR in the LTH group (P < .05, compared to control). Proopiomelanocortin and 22-kDa pro-ACTH did not alter the cortisol response to ACTH treatment. Results from the present study taken together with those of previous in vivo studies suggest that the enhanced cortisol output in the LTH group is not the result of differences in cAMP generation or PKA. We conclude that enhanced cortisol production in LTH adrenals is the result of enhanced protein expression of StAR and potential downstream signaling pathways.
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Affiliation(s)
- Vladimir E Vargas
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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Monau TR, Vargas VE, Zhang L, Myers DA, Ducsay CA. Nitric oxide inhibits ACTH-induced cortisol production in near-term, long-term hypoxic ovine fetal adrenocortical cells. Reprod Sci 2010; 17:955-62. [PMID: 20713972 PMCID: PMC2943550 DOI: 10.1177/1933719110376092] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We previously reported that in the sheep fetus, long-term hypoxia (LTH) resulted in elevated basal plasma adrenocorticotropic hormone (ACTH(1- 39)) whereas the cortisol levels were not different from normoxic controls. We also showed that LTH enhances endothelial nitric oxide synthase (eNOS) expression in the fetal adrenal. This study was designed to determine the effect of NO on cortisol production in adrenocortical cells from LTH fetal sheep. Ewes were maintained at high altitude (3820 m) from ∼40 days' gestation (dG) to near term. Between 138 and 141 dG, fetal adrenal glands were collected from LTH and age-matched normoxic control fetuses. Adrenal cortical cells were pretreated with sodium nitroprusside (SNP), nitro-L-arginine methyl ester (L-NAME), L-arginine, or diethyleneamine NO (DETA-NO) and then challenged with 10 nmol/L ACTH. Cortisol responses were compared after 1 hour. Adrenocorticotropic hormone -induced cortisol secretion was significantly higher in LTH versus control (P < .01). Enhancement of NO with L-arginine resulted in a significant reduction of ACTH-mediated cortisol production in the LTH group. DETA-NO also caused a significant decrease in ACTH-mediated cortisol production (P < .05). Inhibition of NOS with L-NAME significantly increased cortisol production in the LTH group (P < .05 compared to ACTH alone), whereas the effect on the control group was not significant. Nitric oxide synthase activity was significantly higher in the LTH group compared to control, but this difference was eliminated following ACTH treatment. These data indicate that LTH enhances adrenal cortical sensitivity to the inhibitory effects of NO on cortisol production. Nitric oxide may, therefore, play an important role in regulating ACTH-induced cortisol production in the LTH fetal adrenal.
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Affiliation(s)
- Tshepo R. Monau
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92350
| | - Vladimir E. Vargas
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92350
| | - Lubo Zhang
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92350
| | - Dean A. Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190
| | - Charles A. Ducsay
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92350
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Ducsay CA, Mlynarczyk M, Kaushal KM, Hyatt K, Hanson K, Myers DA. Long-term hypoxia enhances ACTH response to arginine vasopressin but not corticotropin-releasing hormone in the near-term ovine fetus. Am J Physiol Regul Integr Comp Physiol 2009; 297:R892-9. [PMID: 19625690 DOI: 10.1152/ajpregu.00220.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study tested the hypothesis that long-term hypoxia (LTH) results in enhanced fetal corticotrope sensitivity to the ACTH secretagogues, corticotropin-releasing hormone (CRH), and AVP. Ewes were maintained at high altitude (3,820 m) from 40 to 130-131 days of gestation. Upon return to the laboratory, hypoxia was maintained by maternal nitrogen infusion. Vascular catheters were placed in both LTH (n = 4) and normoxic controls (n = 4). Each fetus received a 15-min infusion of either saline, 100 ng/kg of ovine CRH, or 20 ng/kg of AVP/min over 3 consecutive days in a randomized order. Fetal blood samples were collected at 0, 15, 30, 60, and 90 min after the start of infusion and analyzed for ACTH(1-39), ACTH precursors, and cortisol. Anterior pituitaries were collected from additional noninstrumented fetuses for analysis of vasopressin receptor 1b (V1b) mRNA and protein. Basal plasma concentrations of both ACTH(1-39) and ACTH precursors were higher in LTH fetuses and were not altered by saline infusion. In response to CRH, ACTH(1-39) increased in both groups and was higher in the LTH group compared with control (P < 0.05). When analyzed as sum of ACTH(1-39) released (Delta0-90 min) above basal, CRH released equal amounts of ACTH(1-39) in both groups. In LTH fetuses, AVP evoked a greater ACTH(1-39) release (P < 0.05) when analyzed as an increased sum of ACTH(1-39) (Delta0-90 min) above basal. Both CRH and AVP elicited a release of ACTH precursors with no differences observed between LTH and control. AVP and CRH elicited significant increases in cortisol, which were higher in response to AVP than CRH. V1b mRNA and protein were elevated in the anterior pituitary of LTH fetuses compared with control. LTH significantly increases pituitary sensitivity to AVP. This enhanced sensitivity may be a mechanism of our previously observed enhanced corticotrope function.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, Loma Linda Univ. School of Medicine, Loma Linda, CA, 92350, USA.
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Monau TR, Vargas VE, King N, Yellon SM, Myers DA, Ducsay CA. Long-term hypoxia increases endothelial nitric oxide synthase expression in the ovine fetal adrenal. Reprod Sci 2009; 16:865-74. [PMID: 19525401 DOI: 10.1177/1933719109336678] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study was designed to test the hypothesis that fetal adrenal nitric oxide synthase (NOS) is elevated in response to long-term hypoxia (LTH). Pregnant ewes were maintained at high altitude (3820 m) for approximately the last 100 days of gestation. Between days 138 and 141 of gestation, adrenal glands were collected from LTH fetuses and age-matched normoxic controls. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western analysis were used to quantify NOS expression, and NOS distribution was examined by immunohistochemistry and double-staining immunofluorescence for endothelial NOS (eNOS) and 17alpha-hydroxylase (CYP17). Neuronal NOS (nNOS) was expressed at very low levels and with no differences between groups. Expression of eNOS was significantly greater in the LTH group compared with control. Neuronal NOS was distributed throughout the cortex while the greatest density of eNOS was observed in the zona fasciculata/reticularis area and eNOS co-localized with CYP17. We conclude that LTH enhances eNOS expression in the inner adrenal cortex which may play a role in regulation of cortisol biosynthesis in the LTH fetus.
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Affiliation(s)
- Tshepo R Monau
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California 92350, USA
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Wood CE, Powers Fraites M, Keller-Wood M. Blockade of PGHS-2 inhibits the hypothalamus-pituitary-adrenal axis response to cerebral hypoperfusion in the sheep fetus. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1813-9. [PMID: 19297537 DOI: 10.1152/ajpregu.90917.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Decreases in fetal blood pressure stimulate homeostatic stress responses that help return blood pressure to normal levels. Fetal hypothalamus-pituitary-adrenal (HPA) axis responses to hypotension are mediated by chemoreceptor and baroreceptor reflexes and ischemia of the fetal central nervous system. Indomethacin, a nonselective inhibitor of prostaglandin endoperoxide synthase (PGHS)-1 and -2, attenuates the HPA response to hypotension in the fetus. The present study was designed to test the hypothesis that selective inhibition of PGHS-2 also inhibits the HPA response to cerebral hypoperfusion. We studied 13 chronically catheterized fetal sheep (126-136 days gestation). Five fetal sheep were subjected to intracerebroventricular infusion of nimesulide (0.01 mg/day), a specific inhibitor of PGHS-2, and eight were treated with vehicle (DMSO in water) for 5 days. Each fetus was subjected to a 10-min period of brachiocephalic occlusion, which decreased carotid arterial pressure approximately 75% and reflexively increased fetal plasma concentrations of ACTH, POMC, cortisol, and femoral arterial pressure, and decreased fetal heart rate. Nimesulide significantly inhibited the ACTH response to the BCO, while significantly augmenting the reflex cardiovascular response and altering fetal heart rate variability consistent with increased sympathetic nervous system activity. The results of this study demonstrate that the activity of PGHS-2 in the brain is a necessary component of the fetal HPA response to cerebral hypoperfusion in the late-gestation fetal sheep. These results are consistent with those of recent study, in which we demonstrated that the preparturient increase in fetal ACTH secretion depends upon PGHS-2 activity within the fetal brain.
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Affiliation(s)
- Charles E Wood
- Department of Physiology and Functional Genomics, PO Box 100274, University of Florida College of Medicine, Gainesville, FL 32610-0274, USA.
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Root B, Abrassart J, Myers DA, Monau T, Ducsay CA. Expression and distribution of glucocorticoid receptors in the ovine fetal adrenal cortex: effect of long-term hypoxia. Reprod Sci 2008; 15:517-28. [PMID: 18579860 DOI: 10.1177/1933719107311782] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This study was designed to determine if long-term hypoxia (LTH) alters adrenal glucocorticoid receptor (GR) expression in the ovine fetal adrenal cortex. Ewes were maintained at 3820 m from approximately 30 to 138 to 140 days' gestation, and fetal adrenals were collected. Western analysis revealed two approximately 94-kDa GR-alpha isoforms and a lower molecular weight (45 kDa) form. A decreasing trend in the ratio of 94-kDa/45-kDa bands following LTH suggested an increase in GR turnover. Immunohistochemistry demonstrated dense GR staining in the zona glomerulosa with minimal staining in the zona fasciculata in the control group, while dense staining was observed throughout the cortex in LTH. Western analysis and reverse transcription polymerase chain reaction confirmed that the GR- beta isoform is not present or expressed at extremely low levels in the fetal adrenal, hypothalamus, pituitary, and placenta. These data indicate that LTH alters GR-alpha function in the fetal adrenal cortex and suggest that GR-beta is not expressed in sheep.
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Affiliation(s)
- Brandon Root
- University of Redlands, Redlands, California, USA
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Gersting J, Schaub CE, Keller-Wood M, Wood CE. Inhibition of brain prostaglandin endoperoxide synthase-2 prevents the preparturient increase in fetal adrenocorticotropin secretion in the sheep fetus. Endocrinology 2008; 149:4128-36. [PMID: 18450957 PMCID: PMC2488234 DOI: 10.1210/en.2008-0123] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maturation of the fetal hypothalamus-pituitary-adrenal axis is critical for the timely somatic development of the fetus and readiness for birth. Recently, we proposed that prostaglandin generation within the fetal central nervous system is critical for the modulation of hypotension-induced fetal ACTH secretion. The present study was designed to test the hypothesis that the preparturient increase in fetal ACTH secretion is dependent upon fetal central nervous system prostaglandin synthesis mediated by the activity of prostaglandin endoperoxide synthase (PGHS)-2 (cyclooxygenase-2) in the fetal brain. We performed two studies in chronically catheterized fetal sheep. In the first study, we infused nimesulide or vehicle intracerebroventricularly (i.c.v) into singleton fetal sheep and collected blood samples until spontaneous parturition. Nimesulide significantly delayed parturition, and inhibited fetal ACTH and proopiomelanocortin secretion but did not prevent the preparturient increase in fetal plasma cortisol concentration. In the second study, we used twin fetuses. One fetus received intracerebroventricular nimesulide and the other intracerebroventricular vehicle. Nimesulide reduced brain tissue concentrations of prostaglandin estradiol, while not affecting plasma prostaglandin E(2) concentrations, demonstrating an action restricted to the fetal brain. Nimesulide reduced PGHS-2 mRNA and increased PGHS-2 protein, while not altering PGHS-1 mRNA or protein in most brain regions, suggesting an effect of the inhibitor on PGHS-2 turnover and relative specificity for PGHS-2 in vivo. We conclude that the preparturient increase in fetal ACTH and proopiomelanocortin is dependent upon the activity of PGHS-2 in the fetal brain. However, we also conclude that the timing of parturition is not solely dependent upon ACTH in this species.
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Affiliation(s)
- Jason Gersting
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida 32610-0274, USA
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Myers DA, Hanson K, Mlynarczyk M, Kaushal KM, Ducsay CA. Long-term hypoxia modulates expression of key genes regulating adipose function in the late-gestation ovine fetus. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1312-8. [PMID: 18287225 DOI: 10.1152/ajpregu.00004.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A major function of abdominal adipose in the newborn is nonshivering thermogenesis. Uncoupling protein (UCP) UCP1 and UCP2 play major roles in thermogenesis. The present study tested the hypothesis that long-term hypoxia (LTH) modulates expression of UCP1 and UCP2, and key genes regulating expression of these genes in the late-gestation ovine fetus. Ewes were maintained at high altitude (3,820 m) from 30 to 138 days gestation (dG); perirenal adipose tissue was collected from LTH and age-matched, normoxic control fetuses at 139-141 dG. Quantitative real-time PCR was used to analyze mRNA for UCP1, UCP2, 11beta hydroxysteroid dehydrogenase type 1 (HSD11B1) and 2 (HSD11B2), glucocorticoid receptor (GR), beta3 adrenergic receptor (beta3AR), deiodinase type 1 (DIO1) and DIO2, peroxisome proliferator activated receptor (PPAR) alpha and gamma and PPARgamma coactivator 1 (PGC1alpha). Concentrations of mRNA for UCP1, HSD11B1, PPARgamma, PGC1, DIO1, and DIO2 were significantly higher in perirenal adipose of LTH compared with control fetuses, while mRNA for HSD11B2, GR, or PPARalpha in perirenal adipose did not differ between control and LTH fetuses. The increased expression of UCP1 is likely an adaptive response to LTH, assuring adequate thermogenesis in the event of birth under oxygen-limiting conditions. Because both glucocorticoids and thyroid hormone regulate UCP1 expression, the increase in HSD11B1, DIO1, and DIO2 implicate increased adipose capacity for local synthesis of these hormones. PPARgamma and its coactivator may provide an underlying mechanism via which LTH alters development of the fetal adipocyte. These findings have important implications regarding fetal/neonatal adipose tissue function in response to LTH.
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Affiliation(s)
- Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Schaub CE, Keller-Wood M, Wood CE. Blockade of estrogen receptors decreases CNS and pituitary prostaglandin synthase expression in fetal sheep. Neuroendocrinology 2008; 87:121-8. [PMID: 17934250 PMCID: PMC2793319 DOI: 10.1159/000109664] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 09/11/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Both prostaglandin E2 (PGE2) and estradiol stimulate fetal ACTH secretion and augment fetal ACTH responses to stress. We have reported that estradiol increases prostaglandin endoperoxide synthase-2 (PGHS-2), and we have proposed that there is a positive feedback relationship between estrogen and fetal hypothalamus-pituitary-adrenal (HPA) axis activity that is dependent upon PGHS activity in the fetal brain. The present study was designed to test the hypothesis that blockade of estrogen receptors in the fetal brain decrease PGHS-2 expression and reduces fetal HPA axis activity. METHODS In study 1, six time-dated pregnant ewes with chronically-catheterized twin fetuses were used. In each pregnancy, one twin was treated intracerebroventricularly (icv) with the estrogen receptor antagonist ICI 182,780 (25 microg/day; n = 6) while the other twin served as an age-matched control. In study 2, plasma samples were drawn from 10 singleton chronically-catheterized fetuses on alternating days until the time of spontaneous parturition. RESULTS ICI infusion caused significantly decreased PGHS-2 mRNA abundance in fetal central nervous system and pituitary, with the greatest decreases occurring in hippocampus and pituitary. There were no statistically significant changes in PGHS-1 mRNA. ICI infusion did not significantly change fetal plasma concentrations of pro-opiomelanocortin (POMC), ACTH, or cortisol in fetuses 130-134 days ges- tation (study 1) but did decrease the preparturient rise in plasma pro-opiomelanocortin concentrations in study 2. CONCLUSION We conclude that PGHS-2 expression in the late-gestation fetal brain is in part stimulated by circulating estrogens in fetal plasma. Blockade of CNS estrogen receptors reduces preparturient plasma concentrations of POMC, but does not reduce fetal HPA axis activity in 130-134 day fetal sheep.
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Affiliation(s)
- Christine E. Schaub
- Department of Physiology and Functional Genomics, University of Florida College of Medicine
| | | | - Charles E. Wood
- Department of Physiology and Functional Genomics, University of Florida College of Medicine
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Ducsay CA, Hyatt K, Mlynarczyk M, Root BK, Kaushal KM, Myers DA. Long-term hypoxia modulates expression of key genes regulating adrenomedullary function in the late gestation ovine fetus. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1997-2005. [PMID: 17699566 DOI: 10.1152/ajpregu.00313.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously communicated that long-term hypoxia (LTH) resulted in a selective reduction in plasma epinephrine following acute stress in fetal sheep. The present study tested the hypothesis that LTH selectively reduces adrenomedullary expression of phenylethanolamine-N-methyltransferase (PNMT), the rate-limiting enzyme for epinephrine synthesis. We also examined the effect of LTH on adrenomedullary nicotinic, muscarinic, and glucocorticoid receptor (GR) expression. Ewes were maintained at high altitude (3,820 m) from 30 to 138 days gestation (dGA); adrenomedullary tissue was collected from LTH and age-matched, normoxic control fetuses at 139-141 dGA. Contrary to our hypothesis, in addition to PNMT, adrenomedullary expression (mRNA, protein) of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) were reduced in the LTH fetus. Immunocytochemistry indicated that TH and DBH expression was lower throughout the medulla, while PNMT appeared to reflect a reduction in PNMT-expressing cells. Nicotinic receptor alpha 1, 2, 3, 5, 6, 7, beta 1, 2, and 4 subunits were expressed in the medulla of LTH and control fetuses. Messenger RNA for alpha 1 and 7 and beta 1 and 2 subunits was lower in LTH fetuses. Muscarinic receptors M1, M2, and M3 as well as the GR were also expressed, and no differences were noted between groups. In summary, LTH in fetal sheep has a profound effect on expression of key enzymes mediating adrenomedullary catecholamine synthesis. Further, LTH impacts nicotinic receptor subunit expression potentially altering cholinergic neurotransmission within the medulla. These findings have important implications regarding fetal cardiovascular and metabolic responses to stress in the LTH fetus.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University, California, USA
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Powers MJ, Wood CE. Ketamine inhibits fetal ACTH responses to cerebral hypoperfusion. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1542-9. [PMID: 17158270 PMCID: PMC2793322 DOI: 10.1152/ajpregu.00300.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study tested the effect of ketamine on the fetal reflex responses of late-gestation sheep to brachiocephalic occlusion (BCO), a stimulus that mimics the reduction in cerebral blood flow that results from severe fetal hypotension. Ketamine, a dissociative anesthetic and known noncompetitive antagonist of N-methyl D-aspartate (NMDA) receptors, has previously been shown to impair chemoreceptor responsiveness. Studies from this laboratory suggest that fetal reflex ACTH responses to hypotension are largely mediated by chemoreceptors; therefore, we hypothesized that ketamine would inhibit the reflex hormonal response to BCO. Chronically catheterized fetal sheep were subjected to acute cerebral hypoperfusion through occlusion of the brachiocephalic artery. Fetal blood pressure and heart rate were continuously recorded, and fetal blood samples drawn during the experiment were analyzed with specific hormone assays. Our results demonstrate that ketamine attenuates hemodynamic responses to cerebral hypoperfusion and is a potent inhibitor of ACTH and proopiomelanocortin (POMC)/pro-ACTH release. These data support the hypothesis that fetal reflex responses hypotension are chemoreceptor mediated. Given the potency with which ketamine inhibits ACTH response to fetal hypotension, we suggest that the use of ketamine or other anesthetic or analgesic drugs that block or otherwise interact with the NMDA-glutamate pathways, in late pregnancy or in preterm newborns be reconsidered.
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Affiliation(s)
- Melanie J Powers
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gaineseville, Florida, USA.
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Ducsay CA, Hyatt K, Mlynarczyk M, Kaushal KM, Myers DA. Long-term hypoxia increases leptin receptors and plasma leptin concentrations in the late-gestation ovine fetus. Am J Physiol Regul Integr Comp Physiol 2006; 291:R1406-13. [PMID: 16825421 DOI: 10.1152/ajpregu.00077.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was designed to test the hypothesis that long-term hypoxia (LTH) increases fetal plasma leptin and fetal adipose or placental leptin expression and alters hypothalamic and adrenocortical leptin receptor (OB-R) expression. Pregnant ewes were maintained at high altitude (3,820 m) from day 30 to approximately 130 days of gestation. Reduced Po2 was maintained in the laboratory by nitrogen infusion through a maternal tracheal catheter. On day 132, normoxic control and LTH fetuses underwent surgical implantation of vascular catheters (n=6 for each group). Five days after surgery, maternal and fetal arterial blood samples were collected for leptin, insulin, and glucose analysis. Placental tissue, periadrenal fat, and fetal hypothalami and adrenal glands were collected from additional control (n=7) and LTH (n=8) fetuses for analysis of leptin mRNA by quantitative, real-time, RT-PCR (qRT-PCR). There was a significant (P<0.03) elevation in fetal plasma leptin in the LTH fetuses (3.5+/-0.7 ng/ml) vs. control (1.1+/-0.1 ng/ml). There were no differences in either glucose or insulin concentrations between the two groups. Periadrenal adipose leptin mRNA was significantly higher in the LTH group compared with control, as was placental leptin expression. The levels of leptin mRNA in adipose were approximately 70 times higher vs. placenta. LTH significantly reduced expression of OB-Ra (short-isoform) in the hypothalamus (P=0.0156), while resulting in a significant increase in adrenal OB-Rb (long-form) expression (P<0.03). Our data suggest that leptin is a hypoxia-inducible gene in the ovine fetus and OB-R expression is altered by LTH. These changes may be responsible in part, for our previously observed alterations in fetal hypothalamic-pituitary-adrenal function following LTH.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University, School of Medicine, CA, USA
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Myers DA, Hyatt K, Mlynarczyk M, Bird IM, Ducsay CA. Long-term hypoxia represses the expression of key genes regulating cortisol biosynthesis in the near-term ovine fetus. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1707-14. [PMID: 16099825 DOI: 10.1152/ajpregu.00343.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Basal plasma ACTH(1-39) concentrations are elevated in long-term hypoxic (LTH) fetal sheep. This study was designed to determine whether the expression of genes regulating cortisol biosynthesis was altered after LTH. Pregnant ewes were maintained at high altitude (3,820 m) from day 30 of gestation to near term, when the animals were transported to the laboratory. Reduced PO2 was maintained by nitrogen infusion through a maternal tracheal catheter. On days 137-141, fetal adrenal glands were collected from LTH and normoxic control fetuses. Real-time PCR was used to quantify mRNA for steroidogenic acute regulatory protein, 17alpha-hydroxylase (CYP17), 21-hydroxylase (CYP21), cholesterol side-chain cleavage (CYP11A1), 3beta-hydroxysteroid dehydrogenase type II (HSD3B2), and the ACTH receptor. We analyzed mRNA by slot-blot hybridization and also quantified mRNA for transcription factors necessary for adrenocortical development by quantitative real-time PCR: steroidogenic factor 1 and dosage-sensitive sex reversal, adrenal hypoplasia congenital, critical region on the X chromosome (DAX-1). Protein was quantified by Western blot analysis. Adrenal mRNAs for CYP17, CYP11A1, and the ACTH receptor were significantly reduced in LTH fetal sheep compared with levels shown in controls. Similarly, CYP11A1 protein and CYP17 protein were reduced in the LTH group. CYP21, steroidogenic acute regulatory protein, HSD3B2, steroidogenic factor 1, and DAX-1 expressions were not altered in response to LTH. We conclude that expression of two key steroidogenic enzymes (CYP17, CYP11A1) regulating cortisol biosynthesis and the ACTH receptor is lower in response to LTH. This likely represents an adaptive response to LTH, to prevent excessive cortisol production that would restrict fetal growth and potentially induce preterm delivery.
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Affiliation(s)
- Dean A Myers
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, USA
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