title: Long-Term Gestational Hypoxia Modulates Expression of Key Genes Governing Mitochondrial Function in the Perirenal Adipose of the Late Gestation Sheep Fetus.
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.
authors.affiliation: Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA dean-myers@ouhsc.edu.
authors.forename: Dean A
authors.initials: DA
authors.lastname: Myers
authors.affiliation: Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Krista
authors.initials: K
authors.lastname: Singleton
authors.affiliation: Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Hyatt
authors.affiliation: Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Mlynarczyk
authors.affiliation: Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA.
authors.forename: Kanchan M
authors.initials: KM
authors.lastname: Kaushal
authors.affiliation: Center for Perinatal Biology, Loma Linda University, School of Medicine, Loma Linda, CA, USA.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Ducsay
mesh_terms: D000222:Adaptation, Physiological; D002001:Adipose Tissue, Brown / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D049109:Cell Proliferation; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D004734:Energy Metabolism / Q000235:genetics; D005260:Female; D005311:Fetal Hypoxia / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D050152:Intra-Abdominal Fat / Q000378:metabolism* / Q000503:physiopathology; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D007668:Kidney; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D051266:Nuclear Respiratory Factor 1 / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011247:Pregnancy; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012756:Sheep; D022722:Thermogenesis; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D024101:Mitochondrial Proteins; D051267:NF-E2-Related Factor 2; D051266:Nuclear Respiratory Factor 1; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D014157:Transcription Factors; C422562:mitochondrial transcription factor A; D052250:Nitric Oxide Synthase Type III; D003576:Electron Transport Complex IV
keywords: adipose; fetus; hypoxia; mitochondria; ovine; sheep