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Ma Q, Xu H, Wei Y, Liang M. Effects of acute hypoxia on nutrient metabolism and physiological function in turbot, Scophthalmus maximus. FISH PHYSIOLOGY AND BIOCHEMISTRY 2024; 50:367-383. [PMID: 36609890 DOI: 10.1007/s10695-022-01154-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Acute hypoxia is a common stress in aquaculture, and causes energy deficiency, oxidative damage and death in fish. Many studies have confirmed that acute hypoxia activated hif1α expression, anaerobic glycolysis and antioxidant system in fish, but the effects of acute hypoxia on lipid and protein metabolism, organelle damage, and the functions of hif2α and hif3α in economic fishes have not been well evaluated. In the present study, turbot was exposed to acute hypoxia (2.0 ± 0.5 mg/L) for 6 h, 12 h, and 24 h, respectively. Then, the contents of hemoglobin (HB), metabolite, gene expressions of hifα isoforms, energy homeostasis, endoplasmic reticulum (ER) stress, and apoptosis were measured. The results suggested that turbot is intolerant to acute hypoxia and the asphyxiation point is about 1.5 mg/L. Acute hypoxia induced perk-mediated ER stress, and increased lipid peroxidation and liver injury in turbot. The blood HB level and liver vegfab expression were increased under hypoxia, which enhances oxygen transport. At hypoxia stress, hif3α, anaerobic glycolysis-related genes expression, and lactate content were increased in the liver, and glycogen was broken down to ensure ATP supply. Meanwhile, hif2α, lipid synthesis-related genes expression, and TG content were increased in the liver, but the lipid catabolism and protein synthesis were suppressed during hypoxia, which reduced the oxygen consumption and ROS generation. Our results systematically illustrate the metabolic and physiological changes under acute hypoxia in turbot, and provide important guidance to improve hypoxia tolerance in fish.
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Affiliation(s)
- Qiang Ma
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, China
| | - Houguo Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266237, China
| | - Yuliang Wei
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266237, China
| | - Mengqing Liang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, China.
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266237, China.
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Scariot PPM, Papoti M, Polisel EEC, Orsi JB, Van Ginkel PR, Prolla TA, Manchado-Gobatto FB, Gobatto CA. Living high - training low model applied to C57BL/6J mice: Effects on physiological parameters related to aerobic fitness and acid-base balance. Life Sci 2023; 317:121443. [PMID: 36709910 DOI: 10.1016/j.lfs.2023.121443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023]
Abstract
There is a scarcity of data regarding the acclimation to high altitude (hypoxic environment) accompanied by training at low altitude (normoxic conditions), the so-called "living high-training low" (LHTL) model in rodents. We aimed to investigate the effects of aerobic training on C57BL/6J mice living in normoxic (NOR) or hypoxic (HYP) environments on several parameters, including critical velocity (CV), a parameter regarded as a measure of aerobic capacity, on monocarboxylate transporters (MCTs) in muscles and hypothalamus, as well as on hematological parameters and body temperature. In each environment, mice were divided into non-trained (N) and trained (T). Forty rodents were distributed into the following experimental groups (N-NOR; T-NOR; N-HYP and T-HYP). HYP groups were in a normobaric tent where oxygen-depleted air was pumped from a hypoxia generator set an inspired oxygen fraction [FiO2] of 14.5 %. The HYP-groups were kept (18 h per day) in a normobaric tent for consecutive 8-weeks. Training sessions were conducted in normoxic conditions ([FiO2] = 19.5 %), 5 times per week (40 min per session) at intensity equivalent to 80 % of CV. In summary, eight weeks of LHTL did not promote a greater improvement in the CV, protein expression of MCTs in different tissues when compared to the application of training alone. The LHTL model increased red blood cells count, but reduced hemoglobin per erythrocyte was found in mice exposed to LHTL. Although the LHTL did not have a major effect on thermographic records, exercise-induced hyperthermia (in the head) was attenuated in HYP groups when compared to NOR groups.
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Affiliation(s)
- Pedro Paulo Menezes Scariot
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil
| | - Marcelo Papoti
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, SP, Brazil
| | | | - Juan Bordon Orsi
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil
| | - Paul R Van Ginkel
- Department of Genetics & Medical Genetics, University of Wisconsin, Madison, WI, USA
| | - Tomas A Prolla
- Department of Genetics & Medical Genetics, University of Wisconsin, Madison, WI, USA
| | | | - Claudio Alexandre Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Limeira, SP, Brazil.
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3
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Ma X, Pan Y, Xue Y, Li Y, Zhang Y, Zhao Y, Xiong X, Wang J, Yang Z. Tetrahydrocurcumin Ameliorates Acute Hypobaric Hypoxia-Induced Cognitive Impairment in Mice. High Alt Med Biol 2022; 23:264-272. [PMID: 35723652 DOI: 10.1089/ham.2021.0061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ma, Xuexinyu, Yang Pan, Yuye Xue, Yao Li, Yan Zhang, Yani Zhao, Xingzhao Xiong, Jianbo Wang, and Zhifu Yang. Tetrahydrocurcumin ameliorates acute hypobaric hypoxia-induced cognitive impairment in mice. High Alt Med Biol. 23:264-272, 2022. Background: Hypobaric hypoxia (HH) impairs spatial learning and increases oxidative stress in rodents. We hypothesized that tetrahydrocurcumin (THC) may attenuate HH-induced neurobehavioral deficits by reducing HH-induced lipid peroxidation and increasing glycolytic activity. Materials and Methods: A C57BL/6 mouse model of acute high altitude brain injury was established using an animal decompression chamber for 24 hours. Cognitive and behavioral assessments were conducted using the Y-maze, open field, and Rotarod tests. We measured superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity; malondialdehyde (MDA) and reactive oxygen species levels; anti-neuronal core antigen (NeuN) immunoreactivity; and active occludin, hypoxia-inducible factor-1α, glucose transporter 1 (GLUT1), and GLUT3 expression levels in mice brain tissue. Results: The mice in the THC group showed improved cognitive impairment compared with those in the HH group in cognitive and behavioral tests, but failed to show improvement in the decline in coordination. The mice in the THC group were more effected than those in the HH group in demonstrating alleviation of hyperemia in cortical vessels and cell voids, and cells in the CA1 region were more closely arranged. Compared with those in the mice of the HH group, the concentration of MDA decreased significantly, the expression of occludin, NeuN immunoreactivity, and the activities of SOD and GSH-Px significantly increased in the mice of the THC group. An increase in GLUT1 expression was observed in HH-exposed animals (N group vs. HH group: 0.4 ± 0.08 vs. 0.60 ± 0.07, p < 0.05), and this increase was enhanced in animals treated with THC (HH group vs. THC group: 0.60 ± 0.07 vs. 0.82 ± 0.08, p < 0.05). Conclusions: THC improved cognitive impairment in mice, accompanied by reduced oxidative stress and increased GLUT1 protein levels.
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Affiliation(s)
- Xuexinyu Ma
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, P.R. China.,Department of Pharmacy, Xian Daxing Hospital, Xi'an, P.R. China
| | - Yang Pan
- Department of Chinese Materia Medica and Natural Medicines, School of Pharmacy, The Air Force Medical University, Xi'an, P.R. China
| | - Yuye Xue
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, P.R. China
| | - Yao Li
- Faculty of Life Science & Medicine, Northwest University, Xi'an, P.R. China
| | - Yan Zhang
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, P.R. China
| | - Yani Zhao
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, P.R. China
| | - Xingzhao Xiong
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA
| | - Jianbo Wang
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, P.R. China.,Sichuan Institute for Translational Chinese Medicine, Chengdu, P.R. China.,Sichuan Academy of Chinese Medical Sciences, Chengdu, P.R. China
| | - Zhifu Yang
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, P.R. China
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4
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Sharma V, Singh TG, Mannan A. Therapeutic implications of glucose transporters (GLUT) in cerebral ischemia. Neurochem Res 2022; 47:2173-2186. [PMID: 35596882 DOI: 10.1007/s11064-022-03620-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 01/05/2023]
Abstract
Cerebral ischemia is a leading cause of death in the globe, with a large societal cost. Deprivation of blood flow, together with consequent glucose and oxygen shortage, activates a variety of pathways that result in permanent brain damage. As a result, ischemia raises energy demand, which is linked to significant alterations in brain energy metabolism. Even at the low glucose levels reported in plasma during ischemia, glucose transport activity may adjust to assure the supply of glucose to maintain normal cellular function. Glucose transporters in the brain are divided into two groups: sodium-independent glucose transporters (GLUTs) and sodium-dependent glucose cotransporters (SGLTs).This review assess the GLUT structure, expression, regulation, pathobiology of GLUT in cerebral ischemia and regulators of GLUT and it also provides the synopsis of the literature exploring the relationship between GLUT and the various downstream signalling pathways for e.g., AMP-activated protein kinase (AMPK), CREB (cAMP response element-binding protein), Hypoxia-inducible factor 1 (HIF)-1, Phosphatidylinositol 3-kinase (PI3-K), Mitogen-activated protein kinase (MAPK) and adenylate-uridylate-rich elements (AREs). Therefore, the aim of the present review was to elaborate the therapeutic implications of GLUT in the cerebral ischemia.
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Affiliation(s)
- Veerta Sharma
- Chitkara College of Pharmacy, Chitkara University, 140401, Patiala, Punjab, India
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, 140401, Patiala, Punjab, India.
| | - Ashi Mannan
- Chitkara College of Pharmacy, Chitkara University, 140401, Patiala, Punjab, India
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5
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Ishida N, Saito M, Sato S, Tezuka Y, Sanbe A, Taira E, Hirose M. Mizagliflozin, a selective SGLT1 inhibitor, improves vascular cognitive impairment in a mouse model of small vessel disease. Pharmacol Res Perspect 2021; 9:e00869. [PMID: 34586752 PMCID: PMC8480397 DOI: 10.1002/prp2.869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 12/25/2022] Open
Abstract
Previously, we showed that sodium/glucose cotransporter 1 (SGLT1) participates in vascular cognitive impairment in small vessel disease. We hypothesized that SGLT1 inhibitors can improve the small vessel disease induced-vascular cognitive impairment. We examined the effects of mizagliflozin, a selective SGLT1 inhibitor, and phlorizin, a non-selective SGLT inhibitor, on vascular cognitive impairment in a mouse model of small vessel disease. Small vessel disease was created using a mouse model of asymmetric common carotid artery surgery (ACAS). Two and/or 4 weeks after ACAS, all experiments were performed. Cerebral blood flow (CBF) was decreased in ACAS compared with sham-operated mice. Phlorizin but not mizagliflozin reversed the decreased CBF of ACAS mice. Both mizagliflozin and phlorizin reversed the ACAS-induced decrease in the latency to fall in a wire hang test of ACAS mice. Moreover, they reversed the ACAS-induced longer escape latencies in the Morris water maze test of ACAS mice. ACAS increased SGLT1 and proinflammatory cytokine gene expressions in mouse brains and phlorizin but not mizagliflozin normalized all gene expressions in ACAS mice. Hematoxylin/eosin staining demonstrated that they inhibited pyknotic cell death in the ACAS mouse hippocampus. In PC12HS cells, IL-1β increased SGLT1 expression and decreased survival rates of cells. Both mizagliflozin and phlorizin increased the survival rates of IL-1β-treated PC12HS cells. These results suggest that mizagliflozin and phlorizin can improve vascular cognitive impairment through the inhibition of neural SGLT1 and phlorizin also does so through the improvement of CBF in a mouse model of small vessel disease.
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Affiliation(s)
- Nanae Ishida
- Division of Molecular and Cellular PharmacologyDepartment of Pathophysiology and PharmacologyIwate Medical UniversitySchool of Pharmaceutical SciencesIwateJapan
| | - Maki Saito
- Department of PharmacyIryo Sosei UniversityFukushimaJapan
| | - Sachiko Sato
- Department of PharmacologyIwate Medical UniversitySchool of MedicineIwateJapan
| | - Yu Tezuka
- Division of PharmacotherapeuticsDepartment of Pathophysiology and PharmacologyIwate Medical University School of Pharmaceutical SciencesIwateJapan
| | - Atsushi Sanbe
- Division of PharmacotherapeuticsDepartment of Pathophysiology and PharmacologyIwate Medical University School of Pharmaceutical SciencesIwateJapan
| | - Eiichi Taira
- Department of PharmacologyIwate Medical UniversitySchool of MedicineIwateJapan
| | - Masamichi Hirose
- Division of Molecular and Cellular PharmacologyDepartment of Pathophysiology and PharmacologyIwate Medical UniversitySchool of Pharmaceutical SciencesIwateJapan
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6
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Sun C, Huang J, Wang Y, Zhao X, Su L, Thomas GWC, Zhao M, Zhang X, Jungreis I, Kellis M, Vicario S, Sharakhov IV, Bondarenko SM, Hasselmann M, Kim CN, Paten B, Penso-Dolfin L, Wang L, Chang Y, Gao Q, Ma L, Ma L, Zhang Z, Zhang H, Zhang H, Ruzzante L, Robertson HM, Zhu Y, Liu Y, Yang H, Ding L, Wang Q, Ma D, Xu W, Liang C, Itgen MW, Mee L, Cao G, Zhang Z, Sadd BM, Hahn MW, Schaack S, Barribeau SM, Williams PH, Waterhouse RM, Mueller RL. Genus-Wide Characterization of Bumblebee Genomes Provides Insights into Their Evolution and Variation in Ecological and Behavioral Traits. Mol Biol Evol 2021; 38:486-501. [PMID: 32946576 PMCID: PMC7826183 DOI: 10.1093/molbev/msaa240] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bumblebees are a diverse group of globally important pollinators in natural ecosystems and for agricultural food production. With both eusocial and solitary life-cycle phases, and some social parasite species, they are especially interesting models to understand social evolution, behavior, and ecology. Reports of many species in decline point to pathogen transmission, habitat loss, pesticide usage, and global climate change, as interconnected causes. These threats to bumblebee diversity make our reliance on a handful of well-studied species for agricultural pollination particularly precarious. To broadly sample bumblebee genomic and phenotypic diversity, we de novo sequenced and assembled the genomes of 17 species, representing all 15 subgenera, producing the first genus-wide quantification of genetic and genomic variation potentially underlying key ecological and behavioral traits. The species phylogeny resolves subgenera relationships, whereas incomplete lineage sorting likely drives high levels of gene tree discordance. Five chromosome-level assemblies show a stable 18-chromosome karyotype, with major rearrangements creating 25 chromosomes in social parasites. Differential transposable element activity drives changes in genome sizes, with putative domestications of repetitive sequences influencing gene coding and regulatory potential. Dynamically evolving gene families and signatures of positive selection point to genus-wide variation in processes linked to foraging, diet and metabolism, immunity and detoxification, as well as adaptations for life at high altitudes. Our study reveals how bumblebee genes and genomes have evolved across the Bombus phylogeny and identifies variations potentially linked to key ecological and behavioral traits of these important pollinators.
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Affiliation(s)
- Cheng Sun
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaxing Huang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yun Wang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Xiaomeng Zhao
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Long Su
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Gregg W C Thomas
- Division of Biological Sciences, University of Montana, Missoula, MT
| | - Mengya Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xingtan Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Irwin Jungreis
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, MA.,Broad Institute of MIT and Harvard, Cambridge, MA
| | - Manolis Kellis
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, MA.,Broad Institute of MIT and Harvard, Cambridge, MA
| | - Saverio Vicario
- Institute of Atmospheric Pollution Research-Italian National Research Council C/O Department of Physics, University of Bari, Bari, Italy
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA.,Department of Cytology and Genetics, Tomsk State University, Tomsk, Russian Federation
| | - Semen M Bondarenko
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA
| | - Martin Hasselmann
- Department of Livestock Population Genomics, Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Chang N Kim
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA
| | - Benedict Paten
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA
| | | | - Li Wang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yuxiao Chang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Qiang Gao
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Ling Ma
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Lina Ma
- China National Center for Bioinformation & Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Zhang Zhang
- China National Center for Bioinformation & Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Hongbo Zhang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Huahao Zhang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, China
| | - Livio Ruzzante
- Department of Ecology and Evolution, University of Lausanne, and Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hugh M Robertson
- Department of Entomology, University of Illinois at Urbana-Champaign, Champaign, IL
| | - Yihui Zhu
- Department of Medical Microbiology and Immunology, Genome Center, and MIND Institute, University of California Davis, Davis, CA
| | - Yanjie Liu
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huipeng Yang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lele Ding
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Quangui Wang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dongna Ma
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Weilin Xu
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Cheng Liang
- Institute of Sericultural and Apiculture, Yunnan Academy of Agricultural Sciences, Mengzi, China
| | - Michael W Itgen
- Department of Biology, Colorado State University, Fort Collins, CO
| | - Lauren Mee
- Department of Ecology, Evolution and Behaviour, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Gang Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Ze Zhang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Matthew W Hahn
- Department of Biology, Indiana University, Bloomington, IN.,Department of Computer Science, Indiana University, Bloomington, IN
| | | | - Seth M Barribeau
- Department of Ecology, Evolution and Behaviour, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Paul H Williams
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Robert M Waterhouse
- Department of Ecology and Evolution, University of Lausanne, and Swiss Institute of Bioinformatics, Lausanne, Switzerland
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7
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Gambardella I, Ascione R, D'Agostino DP, Ari C, Worku B, Tranbaugh RF, Ivascu N, Villena-Vargas J, Girardi LN. Systematic Review - Neuroprotection of ketosis in acute injury of the mammalian central nervous system: A meta-analysis. J Neurochem 2021; 158:105-118. [PMID: 33675563 DOI: 10.1111/jnc.15341] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/27/2021] [Indexed: 11/27/2022]
Abstract
To evaluate the neuroprotection exerted by ketosis against acute damage of the mammalian central nervous system (CNS). Search engines were interrogated to identify experimental studies comparing the mitigating effect of ketosis (intervention) versus non-ketosis (control) on acute CNS damage. Primary endpoint was a reduction in mortality. Secondary endpoints were a reduction in neuronal damage and dysfunction, and an 'aggregated advantage' (composite of all primary and secondary endpoints). Hedges' g was the effect measure. Subgroup analyses evaluated the modulatory effect of age, insult type, and injury site. Meta-regression evaluated timing, type, and magnitude of intervention as predictors of neuroprotection. The selected publications were 49 experimental murine studies (period 1979-2020). The intervention reduced mortality (g 2.45, SE 0.48, p < .01), neuronal damage (g 1.96, SE 0.23, p < .01) and dysfunction (g 0.99, SE 0.10, p < .01). Reduction of mortality was particularly pronounced in the adult subgroup (g 2.71, SE 0.57, p < .01). The aggregated advantage of ketosis was stronger in the pediatric (g 3.98, SE 0.71, p < .01), brain (g 1.96, SE 0.18, p < .01), and ischemic insult (g 2.20, SE 0.23, p < .01) subgroups. Only the magnitude of intervention was a predictor of neuroprotection (g 0.07, SE 0.03, p 0.01 per every mmol/L increase in ketone levels). Ketosis exerts a potent neuroprotection against acute damage to the mammalian CNS in terms of reduction of mortality, of neuronal damage and dysfunction. Hematic levels of ketones are directly proportional to the effect size of neuroprotection.
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Affiliation(s)
| | - Raimondo Ascione
- Bristol Translational Biomedical Research Centre, University of Bristol, Bristol, UK
| | - Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, USA
| | - Csilla Ari
- Behavioral Neuroscience Research Laboratory, Department of Psychology, University of South Florida, Tampa, FL, USA
| | - Berhane Worku
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Robert F Tranbaugh
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Natalia Ivascu
- Department of Anesthesia, Weill Cornell Medicine, New York, NY, USA
| | | | - Leonard N Girardi
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
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8
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Verkhratsky A, Semyanov A, Zorec R. Physiology of Astroglial Excitability. FUNCTION (OXFORD, ENGLAND) 2020; 1:zqaa016. [PMID: 35330636 PMCID: PMC8788756 DOI: 10.1093/function/zqaa016] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/29/2020] [Accepted: 09/03/2020] [Indexed: 01/06/2023]
Abstract
Classic physiology divides all neural cells into excitable neurons and nonexcitable neuroglia. Neuroglial cells, chiefly responsible for homeostasis and defense of the nervous tissue, coordinate their complex homeostatic responses with neuronal activity. This coordination reflects a specific form of glial excitability mediated by complex changes in intracellular concentration of ions and second messengers organized in both space and time. Astrocytes are equipped with multiple molecular cascades, which are central for regulating homeostasis of neurotransmitters, ionostasis, synaptic connectivity, and metabolic support of the central nervous system. Astrocytes are further provisioned with multiple receptors for neurotransmitters and neurohormones, which upon activation trigger intracellular signals mediated by Ca2+, Na+, and cyclic AMP. Calcium signals have distinct organization and underlying mechanisms in different astrocytic compartments thus allowing complex spatiotemporal signaling. Signals mediated by fluctuations in cytosolic Na+ are instrumental for coordination of Na+ dependent astrocytic transporters with tissue state and homeostatic demands. Astroglial ionic excitability may also involve K+, H+, and Cl-. The cyclic AMP signalling system is, in comparison to ions, much slower in targeting astroglial effector mechanisms. This evidence review summarizes the concept of astroglial intracellular excitability.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK,Achucarro Center for Neuroscience, Ikerbasque, 48011 Bilbao, Spain,Address correspondence to A.V. (e-mail: )
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia,Faculty of Biology, Moscow State University, Moscow, Russia,Sechenov First Moscow State Medical University, Moscow, Russia
| | - Robert Zorec
- Celica Biomedical, Ljubljana 1000, Slovenia,Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana 1000, Slovenia
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9
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Glucose transporters in brain in health and disease. Pflugers Arch 2020; 472:1299-1343. [PMID: 32789766 PMCID: PMC7462931 DOI: 10.1007/s00424-020-02441-x] [Citation(s) in RCA: 219] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
Energy demand of neurons in brain that is covered by glucose supply from the blood is ensured by glucose transporters in capillaries and brain cells. In brain, the facilitative diffusion glucose transporters GLUT1-6 and GLUT8, and the Na+-d-glucose cotransporters SGLT1 are expressed. The glucose transporters mediate uptake of d-glucose across the blood-brain barrier and delivery of d-glucose to astrocytes and neurons. They are critically involved in regulatory adaptations to varying energy demands in response to differing neuronal activities and glucose supply. In this review, a comprehensive overview about verified and proposed roles of cerebral glucose transporters during health and diseases is presented. Our current knowledge is mainly based on experiments performed in rodents. First, the functional properties of human glucose transporters expressed in brain and their cerebral locations are described. Thereafter, proposed physiological functions of GLUT1, GLUT2, GLUT3, GLUT4, and SGLT1 for energy supply to neurons, glucose sensing, central regulation of glucohomeostasis, and feeding behavior are compiled, and their roles in learning and memory formation are discussed. In addition, diseases are described in which functional changes of cerebral glucose transporters are relevant. These are GLUT1 deficiency syndrome (GLUT1-SD), diabetes mellitus, Alzheimer’s disease (AD), stroke, and traumatic brain injury (TBI). GLUT1-SD is caused by defect mutations in GLUT1. Diabetes and AD are associated with changed expression of glucose transporters in brain, and transporter-related energy deficiency of neurons may contribute to pathogenesis of AD. Stroke and TBI are associated with changes of glucose transporter expression that influence clinical outcome.
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Verkhratsky A, Rose CR. Na +-dependent transporters: The backbone of astroglial homeostatic function. Cell Calcium 2019; 85:102136. [PMID: 31835178 DOI: 10.1016/j.ceca.2019.102136] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/30/2019] [Accepted: 11/30/2019] [Indexed: 01/30/2023]
Abstract
Astrocytes are the principal homeostatic cells of the central nerves system (CNS) that support the CNS function at all levels of organisation, from molecular to organ. Several fundamental homeostatic functions of astrocytes are mediated through plasmalemmal pumps and transporters; most of which are also regulated by the transplasmalemmal gradient of Na+ ions. Neuronal activity as well as mechanical or chemical stimulation of astrocytes trigger plasmalemmal Na+ fluxes, which in turn generate spatio-temporally organised transient changes in the cytosolic Na+ concentration, which represent the substrate of astroglial Na+ signalling. Astroglial Na+ signals link and coordinate neuronal activity and CNS homeostatic demands with the astroglial homeostatic response.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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11
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Laouafa S, Roussel D, Marcouiller F, Soliz J, Gozal D, Bairam A, Joseph V. Roles of oestradiol receptor alpha and beta against hypertension and brain mitochondrial dysfunction under intermittent hypoxia in female rats. Acta Physiol (Oxf) 2019; 226:e13255. [PMID: 30635990 DOI: 10.1111/apha.13255] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 12/20/2022]
Abstract
AIM Chronic intermittent hypoxia (CIH) induces systemic (hypertension) and central alterations (mitochondrial dysfunction underlying cognitive deficits). We hypothesized that agonists of oestradiol receptors (ER) α and β prevent CIH-induced hypertension and brain mitochondrial dysfunction. METHODS Ovariectomized female rats were implanted with osmotic pumps delivering vehicle (Veh), the ERα agonist propylpyraoletriol (PPT - 30 μg/kg/day) or the ERβ agonist diarylpropionitril (DPN - 100 μg/kg/day). Animals were exposed to CIH (21%-10% FI O2 - 10 cycles/hour - 8 hours/day - 7 days) or normoxia. Arterial blood pressure was measured after CIH or normoxia exposures. Mitochondrial respiration and H2 O2 production were measured in brain cortex with high-resolution respirometry, as well as activity of complex I and IV of the electron transport chain, citrate synthase, pyruvate, and lactate dehydrogenase (PDH and LDH). RESULTS Propylpyraoletriol but not DPN prevented the rise of arterial pressure induced by CIH. CIH exposures decreased O2 consumption, complex I activity, and increased H2 O2 production. CIH had no effect on citrate synthase activity, but decreased PDH activity and increased LDH activity indicating higher anaerobic glycolysis. Propylpyraoletriol and DPN treatments prevented all these alterations. CONCLUSIONS We conclude that in OVX female rats, the ERα agonist prevents from CIH-induced hypertension while both ERα and ERβ agonists prevent the brain mitochondrial dysfunction and metabolic switch induced by CIH. These findings may have implications for menopausal women suffering of sleep apnoea regarding hormonal therapy.
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Affiliation(s)
- Sofien Laouafa
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Université Laval Quebec City Quebec Canada
| | - Damien Roussel
- CNRS, UMR 5023 Université Claude Bernard Lyon 1 Villeurbanne France
| | - François Marcouiller
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Université Laval Quebec City Quebec Canada
| | - Jorge Soliz
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Université Laval Quebec City Quebec Canada
| | - David Gozal
- Department of Child Health University of Missouri School of Medicine Columbia Missouri
| | - Aida Bairam
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Université Laval Quebec City Quebec Canada
| | - Vincent Joseph
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Université Laval Quebec City Quebec Canada
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12
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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13
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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14
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Westergard T, Jensen BK, Wen X, Cai J, Kropf E, Iacovitti L, Pasinelli P, Trotti D. Cell-to-Cell Transmission of Dipeptide Repeat Proteins Linked to C9orf72-ALS/FTD. Cell Rep 2017; 17:645-652. [PMID: 27732842 DOI: 10.1016/j.celrep.2016.09.032] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/05/2016] [Accepted: 09/12/2016] [Indexed: 01/13/2023] Open
Abstract
Aberrant hexanucleotide repeat expansions in C9orf72 are the most common genetic change underlying amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). RNA transcripts containing these expansions undergo repeat-associated non-ATG translation (RAN-T) to form five dipeptide repeat proteins (DPRs). DPRs are found as aggregates throughout the CNS of C9orf72-ALS/FTD patients, and some cause degeneration when expressed in vitro in neuronal cultures and in vivo in animal models. The spread of characteristic disease-related proteins drives the progression of pathology in many neurodegenerative diseases. While DPR toxic mechanisms continue to be investigated, the potential for DPRs to spread has yet to be determined. Using different experimental cell culture platforms, including spinal motor neurons derived from induced pluripotent stem cells from C9orf72-ALS patients, we found evidence for cell-to-cell spreading of DPRs via exosome-dependent and exosome-independent pathways, which may be relevant to disease.
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Affiliation(s)
- Thomas Westergard
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Brigid K Jensen
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Xinmei Wen
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Jingli Cai
- Stem Cell Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Elizabeth Kropf
- Stem Cell Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Lorraine Iacovitti
- Stem Cell Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Piera Pasinelli
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA
| | - Davide Trotti
- Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA.
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15
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Bordt EA. The importance of controlling in vitro oxygen tension to accurately model in vivo neurophysiology. Neurotoxicology 2017; 66:213-220. [PMID: 29102646 DOI: 10.1016/j.neuro.2017.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 12/13/2022]
Abstract
The majority of in vitro studies modeling in vivo conditions are performed on the lab bench in atmospheric air. However, the oxygen tension (pO2) present in atmospheric air (160mm Hg, ∼21% O2) is in great excess to the pO2 that permeates tissues within the brain (5-45mm Hg, ∼1-6% O2). This review will discuss the differentiation between pO2 in the in vivo environment and the pO2 commonly used during in vitro experiments, and how this could affect assay outcomes. Also highlighted are studies linking changes in pO2 to changes in cellular function, particularly the role of pO2 in mitochondrial function, reactive oxygen species production, and cellular growth and differentiation. The role of hypoxia inducible factor 1 and oxygen sensing is also presented. Finally, emerging literature exploring sex differences in tissue oxygenation is discussed.
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Affiliation(s)
- Evan A Bordt
- Department of Pediatrics, Lurie Center for Autism, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA, 02129, USA.
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16
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Gorr TA. Hypometabolism as the ultimate defence in stress response: how the comparative approach helps understanding of medically relevant questions. Acta Physiol (Oxf) 2017; 219:409-440. [PMID: 27364602 DOI: 10.1111/apha.12747] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/28/2016] [Accepted: 06/28/2016] [Indexed: 12/22/2022]
Abstract
First conceptualized from breath-hold diving mammals, later recognized as the ultimate cell autonomous survival strategy in anoxia-tolerant vertebrates and burrowing or hibernating rodents, hypometabolism is typically recruited by resilient organisms to withstand and recover from otherwise life-threatening hazards. Through the coordinated down-regulation of biosynthetic, proliferative and electrogenic expenditures at times when little ATP can be generated, a metabolism turned 'down to the pilot light' allows the re-balancing of energy demand with supply at a greatly suppressed level in response to noxious exogenous stimuli or seasonal endogenous cues. A unifying hallmark of stress-tolerant organisms, the adaptation effectively prevents lethal depletion of ATP, thus delineating a marked contrast with susceptible species. Along with disengaged macromolecular syntheses, attenuated transmembrane ion shuttling and PO2 -conforming respiration rates, the metabolic slowdown in tolerant species usually culminates in a non-cycling, quiescent phenotype. However, such a reprogramming also occurs in leading human pathophysiologies. Ranging from microbial infections through ischaemia-driven infarcts to solid malignancies, cells involved in these disorders may again invoke hypometabolism to endure conditions non-permissive for growth. At the same time, their reduced activities underlie the frequent development of a general resistance to therapeutic interventions. On the other hand, a controlled induction of hypometabolic and/or hypothermic states by pharmacological means has recently stimulated intense research aimed at improved organ preservation and patient survival in situations requiring acutely administered critical care. The current review article therefore presents an up-to-date survey of concepts and applications of a coordinated and reversibly down-regulated metabolic rate as the ultimate defence in stress responses.
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Affiliation(s)
- T. A. Gorr
- Institute of Veterinary Physiology; Vetsuisse Faculty; University of Zurich; Zurich Switzerland
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17
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Jochmans-Lemoine A, Shahare M, Soliz J, Joseph V. HIF1α and physiological responses to hypoxia are correlated in mice but not in rats. J Exp Biol 2016; 219:3952-3961. [DOI: 10.1242/jeb.142869] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/06/2016] [Indexed: 01/06/2023]
Abstract
We previously reported that rats and mice that have been raised for more than 30 generations in La Paz, Bolivia (3600m), display divergent physiological responses to high altitude (HA), including improved respiratory and metabolic control in mice. In the present study we asked whether these traits would also be present in response to hypoxia at sea level (SL). To answer this question, we exposed rats (SD) and mice (FVB) to normoxia (21% O2) or hypoxia (15 and 12% O2) for 6 hours and measured ventilation and metabolic rate (whole body plethysmography), and expression of the transcription factor HIF-1α (ELISA and Mass Spectrometry) and other proteins whose expression are regulated by hypoxia (Glucose Transporter 1, Pyruvate Dehydrogenase Kinase 1, and Angiopoietin 2 - Mass Spectrometry) in the brainstem. In response to hypoxia, compared with rats, mice had higher minute ventilation, lower metabolic rate, and higher expression of HIF-1α in the brainstem. In mice the expression level of HIF-1α was positively correlated with ventilation and negatively correlated with metabolic rate. In rats, the concentration of brainstem cytosolic protein decreased by 38% at 12% O2, while expression of the glucose transporter 1 increased. We conclude that mice and rats raised at sea level have divergent physiological and molecular responses to hypoxia, supporting the hypothesis that mice have innate traits that favor adaptation to altitude.
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Affiliation(s)
- Alexandra Jochmans-Lemoine
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Manju Shahare
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Jorge Soliz
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Vincent Joseph
- Unité de recherche en périnatologie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
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18
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Jagadapillai R, Mellen NM, Sachleben LR, Gozal E. Ceftriaxone preserves glutamate transporters and prevents intermittent hypoxia-induced vulnerability to brain excitotoxic injury. PLoS One 2014; 9:e100230. [PMID: 25014412 PMCID: PMC4094429 DOI: 10.1371/journal.pone.0100230] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 05/24/2014] [Indexed: 12/24/2022] Open
Abstract
Hypoxia alters cellular metabolism and although the effects of sustained hypoxia (SH) have been extensively studied, less is known about chronic intermittent hypoxia (IH), commonly associated with cardiovascular morbidity and stroke. We hypothesize that impaired glutamate homeostasis after chronic IH may underlie vulnerability to stroke-induced excitotoxicity. P16 organotypic hippocampal slices, cultured for 7 days were exposed for 7 days to IH (alternating 2 min 5% O2 - 15 min 21% O2), SH (5% O2) or RA (21% O2), then 3 glutamate challenges. The first and last exposures were intended as a metabolic stimulus (200 µM glutamate, 15 min); the second emulated excitotoxicity (10 mM glutamate, 10 min). GFAP, MAP2, and EAAT1, EAAT2 glutamate transporters expression were assessed after exposure to each hypoxic protocol. Additionally, cell viability was determined at baseline and after each glutamate challenge, in presence or absence of ceftriaxone that increases glutamate transporter expression. GFAP and MAP2 decreased after 7 days IH and SH. Long-term IH but not SH decreased EAAT1 and EAAT2. Excitotoxic glutamate challenge decreased cell viability and the following 200 µM exposure further increased cell death, particularly in IH-exposed slices. Ceftriaxone prevented glutamate transporter decrease and improved cell viability after IH and excitotoxicity. We conclude that IH is more detrimental to cell survival and glutamate homeostasis than SH. These findings suggest that impaired regulation of extracellular glutamate levels is implicated in the increased brain susceptibility to excitotoxic insult after long-term IH.
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Affiliation(s)
- Rekha Jagadapillai
- Department of Pediatrics - KCHRI, University of Louisville, Louisville, Kentucky, United States of America
| | - Nicholas M Mellen
- Department of Pediatrics - KCHRI, University of Louisville, Louisville, Kentucky, United States of America; Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, United States of America
| | - Leroy R Sachleben
- Department of Pediatrics - KCHRI, University of Louisville, Louisville, Kentucky, United States of America
| | - Evelyne Gozal
- Department of Pediatrics - KCHRI, University of Louisville, Louisville, Kentucky, United States of America; Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, United States of America; Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, United States of America
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19
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Nijland PG, Michailidou I, Witte ME, Mizee MR, van der Pol SMA, van Het Hof B, Reijerkerk A, Pellerin L, van der Valk P, de Vries HE, van Horssen J. Cellular distribution of glucose and monocarboxylate transporters in human brain white matter and multiple sclerosis lesions. Glia 2014; 62:1125-41. [PMID: 24692237 DOI: 10.1002/glia.22667] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 12/12/2022]
Abstract
To ensure efficient energy supply to the high demanding brain, nutrients are transported into brain cells via specific glucose (GLUT) and monocarboxylate transporters (MCT). Mitochondrial dysfunction and altered glucose metabolism are thought to play an important role in the progression of neurodegenerative diseases, including multiple sclerosis (MS). Here, we investigated the cellular localization of key GLUT and MCT proteins in human brain tissue of non-neurological controls and MS patients. We show that in control brain tissue GLUT and MCT proteins were abundantly expressed in a variety of central nervous system cells, particularly in microglia and endothelial cells. In active MS lesions, GLUTs and MCTs were highly expressed in infiltrating leukocytes and reactive astrocytes. Astrocytes manifest increased MCT1 staining and maintain GLUT expression in inactive lesions, whereas demyelinated axons exhibit significantly reduced GLUT3 and MCT2 immunoreactivity in inactive lesions. Finally, we demonstrated that the co-transcription factor peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α), an important protein involved in energy metabolism, is highly expressed in reactive astrocytes in active MS lesions. Overexpression of PGC-1α in astrocyte-like cells resulted in increased production of several GLUT and MCT proteins. In conclusion, we provide for the first time a comprehensive overview of key nutrient transporters in white matter brain samples. Moreover, our data demonstrate an altered expression of these nutrient transporters in MS brain tissue, including a marked reduction of axonal GLUT3 and MCT2 expression in chronic lesions, which may impede efficient nutrient supply to the hypoxic demyelinated axons thereby contributing to the ongoing neurodegeneration in MS.
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Affiliation(s)
- Philip G Nijland
- Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands
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20
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Rosafio K, Pellerin L. Oxygen tension controls the expression of the monocarboxylate transporter MCT4 in cultured mouse cortical astrocytes via a hypoxia-inducible factor-1α-mediated transcriptional regulation. Glia 2013; 62:477-90. [PMID: 24375723 DOI: 10.1002/glia.22618] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/29/2013] [Accepted: 12/06/2013] [Indexed: 12/13/2022]
Abstract
The monocarboxylate transporter MCT4 is a high capacity carrier important for lactate release from highly glycolytic cells. In the central nervous system, MCT4 is predominantly expressed by astrocytes. Surprisingly, MCT4 expression in cultured astrocytes is low, suggesting that a physiological characteristic, not met in culture conditions, is necessary. Here we demonstrate that reducing oxygen concentration from 21% to either 1 or 0% restored in a concentration-dependent manner the expression of MCT4 at the mRNA and protein levels in cultured astrocytes. This effect was specific for MCT4 since the expression of MCT1, the other astrocytic monocarboxylate transporter present in vitro, was not altered in such conditions. MCT4 expression was shown to be controlled by the transcription factor hypoxia-inducible factor-1α (HIF-1α) since under low oxygen levels, transfecting astrocyte cultures with a siRNA targeting HIF-1α largely prevented MCT4 induction. Moreover, the prolyl hydroxylase inhibitor dimethyloxalylglycine (DMOG) induced MCT4 expression in astrocytes cultured in presence of 21% oxygen. In parallel, glycolytic activity was enhanced by exposure to 1% oxygen as demonstrated by the increased lactate release, an effect dependent on MCT4 expression. Finally, MCT4 expression was found to be necessary for astrocyte survival when exposed for a prolonged period to 1% oxygen. These data suggest that a major determinant of astrocyte MCT4 expression in vivo is likely the oxygen tension. This could be relevant in areas of high neuronal activity and oxygen consumption, favouring astrocytic lactate supply to neurons. Moreover, it could also play an important role for neuronal recovery after an ischemic episode.
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Affiliation(s)
- Katia Rosafio
- Département de Physiologie, Université de Lausanne, Lausanne, Switzerland
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21
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Jones SM, Novak AE, Elliott JP. The role of HIF in cobalt-induced ischemic tolerance. Neuroscience 2013; 252:420-30. [PMID: 23916558 DOI: 10.1016/j.neuroscience.2013.07.060] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 07/25/2013] [Accepted: 07/25/2013] [Indexed: 12/27/2022]
Abstract
Understanding the endogenous survival pathways induced by ischemic tolerance may yield targets for neuroprotection from stroke. One well-studied pathway reported to be evoked by preconditioning stimuli is the transcription factor HIF (hypoxia-inducible factor). However, whether HIF induction by ischemic insults is neuroprotective or toxic is still unclear. We examined the ability of three prolyl-hydroxylase inhibitors, which induce HIF, to protect hippocampal cultures from oxygen-glucose deprivation. Hippocampal cultures were exposed to ischemic preconditioning or various concentrations of cobalt chloride, deferoxamine (DFO) or dimethyloxylalyglycine (DMOG), prior to lethal oxygen-glucose deprivation (OGD). Cell survival of neurons and astrocytes was determined with dual-label immunocytochemistry. The induction of HIF targets was assessed in mixed as well as astrocyte-enriched cultures. Ischemic preconditioning, as well as low concentrations of cobalt and DFO, enhanced the survival of neurons following OGD. However, DMOG exacerbates OGD-induced neuronal death. At low concentrations, all three prolyl-hydroxylase (PHD) inhibitors increased the survival of astrocytes. Neuroprotective concentrations of cobalt induced the transcription of the cytokine erythropoietin (EPO) in astrocyte cultures. In addition, pretreatment with recombinant human erythropoietin (rH-EPO) also protected neurons from OGD. Our data suggest that HIF-induced EPO, released from astrocytes, protects neurons from OGD. However, the three PHD inhibitors each exhibited different neuroprotective profiles at low concentrations, suggesting that not all PHD inhibitors are created equal. The protective effects at low doses is reminiscent of HIF involvement in ischemic tolerance, in which sub-lethal insults induce HIF pathways resulting in neuroprotection, whereas the high-dose toxicity suggests that over-activation of HIF is not always protective. Therefore, the choice of inhibitor and dose may determine the clinical utility of these compounds. Deferoxamine exhibited little toxicity even at higher doses, and therefore appears a promising candidate for clinical use.
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Affiliation(s)
- S M Jones
- Swedish Medical Center, Englewood, CO 80113, USA.
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Matsumoto S, Saito K, Yasui H, Morris HD, Munasinghe JP, Lizak M, Merkle H, Ardenkjaer-Larsen JH, Choudhuri R, Devasahayam N, Subramanian S, Koretsky AP, Mitchell JB, Krishna MC. EPR oxygen imaging and hyperpolarized 13C MRI of pyruvate metabolism as noninvasive biomarkers of tumor treatment response to a glycolysis inhibitor 3-bromopyruvate. Magn Reson Med 2013; 69:1443-50. [PMID: 22692861 PMCID: PMC3479339 DOI: 10.1002/mrm.24355] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 05/07/2012] [Accepted: 05/08/2012] [Indexed: 12/15/2022]
Abstract
The hypoxic nature of tumors results in treatment resistance and poor prognosis. To spare limited oxygen for more crucial pathways, hypoxic cancerous cells suppress mitochondrial oxidative phosphorylation and promote glycolysis for energy production. Thereby, inhibition of glycolysis has the potential to overcome treatment resistance of hypoxic tumors. Here, EPR imaging was used to evaluate oxygen dependent efficacy on hypoxia-sensitive drug. The small molecule 3-bromopyruvate blocks glycolysis pathway by inhibiting hypoxia inducible enzymes and enhanced cytotoxicity of 3-bromopyruvate under hypoxic conditions has been reported in vitro. However, the efficacy of 3-bromopyruvate was substantially attenuated in hypoxic tumor regions (pO2<10 mmHg) in vivo using squamous cell carcinoma (SCCVII)-bearing mouse model. Metabolic MRI studies using hyperpolarized 13C-labeled pyruvate showed that monocarboxylate transporter-1 is the major transporter for pyruvate and the analog 3-bromopyruvate in SCCVII tumor. The discrepant results between in vitro and in vivo data were attributed to biphasic oxygen dependent expression of monocarboxylate transporter-1 in vivo. Expression of monocarboxylate transporter-1 was enhanced in moderately hypoxic (8-15 mmHg) tumor regions but down regulated in severely hypoxic (<5 mmHg) tumor regions. These results emphasize the importance of noninvasive imaging biomarkers to confirm the action of hypoxia-activated drugs.
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Affiliation(s)
- Shingo Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Keita Saito
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Hironobu Yasui
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - H. Douglas Morris
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, MD, USA
| | - Jeeva P. Munasinghe
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, MD, USA
| | - Martin Lizak
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, MD, USA
| | - Hellmut Merkle
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, MD, USA
| | | | - Rajani Choudhuri
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Sankaran Subramanian
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Alan P. Koretsky
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, MD, USA
| | - James B. Mitchell
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Murali C. Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
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Titler AM, Posimo JM, Leak RK. Astrocyte plasticity revealed by adaptations to severe proteotoxic stress. Cell Tissue Res 2013; 352:427-43. [PMID: 23420451 DOI: 10.1007/s00441-013-1571-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/17/2013] [Indexed: 12/21/2022]
Abstract
Neurodegeneration is characterized by an accumulation of misfolded proteins in neurons. It is less well appreciated that glia often also accumulate misfolded proteins. However, glia are highly plastic and may adapt to stress readily. Endogenous adaptations to stress can be measured by challenging stressed cells with a second hit and then measuring viability. For example, subtoxic stress can elicit preconditioning or tolerance against second hits. However, it is not known if severe stress that kills half the population can elicit endogenous adaptations in the remaining survivors. Glia, with their resilient nature, offer an ideal model in which to test this new hypothesis. The present study is the first demonstration that astrocytes surviving one LC50 hit of the proteasome inhibitor MG132 were protected against a second MG132 hit. ATP loss in response to the second hit was also prevented. MG132 caused compensatory rises in stress-sensitive heat shock proteins. However, stressed astrocytes exhibited an even greater rise in ubiquitin-conjugated proteins upon the second hit, illustrating the severity of the proteotoxicity and verifying the continued impact of MG132. Despite this stress, MG132-pretreated astrocytes were completely prevented from losing glutathione with the second hit. Furthermore, inhibiting glutathione synthesis rendered astrocytes sensitive to the second hit, unmasking the cumulative impact of two hits by removal of an endogenous adaptation. These findings suggest that stressed astrocytes become progressively harder to kill by virtue of antioxidant defenses. Such plasticity may permit astrocytes under severe stress to better support neurons and help explain the protracted nature of neurodegeneration.
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Affiliation(s)
- Amanda M Titler
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, 600 Forbes Ave, Pittsburgh, PA 15282, USA
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Loss of neuron-astroglial interaction rapidly induces protective CNTF expression after stroke in mice. J Neurosci 2012; 32:9277-87. [PMID: 22764235 DOI: 10.1523/jneurosci.1746-12.2012] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Ciliary neurotrophic factor (CNTF) is a potent neural cytokine with very low expression in the CNS, predominantly by astrocytes. CNTF increases rapidly and greatly following traumatic or ischemic injury. Understanding the underlying mechanisms would help to design pharmacological treatments to increase endogenous CNTF levels for neuroprotection. Here, we show that astroglial CNTF expression in the adult mouse striatum is increased twofold within 1 h and increases up to >30-fold over 2 weeks following a focal stroke caused by a transient middle cerebral artery occlusion (MCAO). Selective neuronal loss caused by intrastriatal injection of quinolinic acid resulted in a comparable increase. Cocultured neurons reduced CNTF expression in astrocytes, which was prevented by light trypsinization. RGD (arginine-glycine-aspartic acid) blocking peptides induced CNTF expression, which was dependent on transcription. Astroglial CNTF expression was not affected by diffusible neuronal molecules or by neurotransmitters. The transient ischemia does not seem to directly increase CNTF, as intrastriatal injection of an ischemic solution or exposure of naive mice or cultured cells to severe hypoxia had minimal effects. Inflammatory mechanisms were probably also not involved, as intrastriatal injection of proinflammatory cytokines (IFNγ, IL6) in naive mice had no or small effects, and anti-inflammatory treatments did not diminish the increase in CNTF after MCAO. CNTF-/- mice had more extensive tissue loss and similar astrocyte activation after MCAO than their wild-type littermates. These data suggest that contact-mediated integrin signaling between neurons and astrocytes normally represses CNTF expression and that neuronal dysfunction causes a rapid protective response by the CNS.
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Mahan VL, Zurakowski D, Otterbein LE, Pigula FA. Inhaled carbon monoxide provides cerebral cytoprotection in pigs. PLoS One 2012; 7:e41982. [PMID: 22879904 PMCID: PMC3413707 DOI: 10.1371/journal.pone.0041982] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/27/2012] [Indexed: 11/18/2022] Open
Abstract
Carbon monoxide (CO) at low concentrations imparts protective effects in numerous preclinical small animal models of brain injury. Evidence of protection in large animal models of cerebral injury, however, has not been tested. Neurologic deficits following open heart surgery are likely related in part to ischemia reperfusion injury that occurs during cardiopulmonary bypass surgery. Using a model of deep hypothermic circulatory arrest (DHCA) in piglets, we evaluated the effects of CO to reduce cerebral injury. DHCA and cardiopulmonary bypass (CPB) induced significant alterations in metabolic demands, including a decrease in the oxygen/glucose index (OGI), an increase in lactate/glucose index (LGI) and a rise in cerebral blood pressure that ultimately resulted in increased cell death in the neocortex and hippocampus that was completely abrogated in piglets preconditioned with a low, safe dose of CO. Moreover CO-treated animals maintained normal, pre-CPB OGI and LGI and corresponding cerebral sinus pressures with no change in systemic hemodynamics or metabolic intermediates. Collectively, our data demonstrate that inhaled CO may be beneficial in preventing cerebral injury resulting from DHCA and offer important therapeutic options in newborns undergoing DHCA for open heart surgery.
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Affiliation(s)
- Vicki L Mahan
- Department of Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America.
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26
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Balmaceda-Aguilera C, Cortés-Campos C, Cifuentes M, Peruzzo B, Mack L, Tapia JC, Oyarce K, García MA, Nualart F. Glucose transporter 1 and monocarboxylate transporters 1, 2, and 4 localization within the glial cells of shark blood-brain-barriers. PLoS One 2012; 7:e32409. [PMID: 22389700 PMCID: PMC3289654 DOI: 10.1371/journal.pone.0032409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 01/29/2012] [Indexed: 12/22/2022] Open
Abstract
Although previous studies showed that glucose is used to support the metabolic activity of the cartilaginous fish brain, the distribution and expression levels of glucose transporter (GLUT) isoforms remained undetermined. Optic/ultrastructural immunohistochemistry approaches were used to determine the expression of GLUT1 in the glial blood-brain barrier (gBBB). GLUT1 was observed solely in glial cells; it was primarily located in end-feet processes of the gBBB. Western blot analysis showed a protein with a molecular mass of 50 kDa, and partial sequencing confirmed GLUT1 identity. Similar approaches were used to demonstrate increased GLUT1 polarization to both apical and basolateral membranes in choroid plexus epithelial cells. To explore monocarboxylate transporter (MCT) involvement in shark brain metabolism, the expression of MCTs was analyzed. MCT1, 2 and 4 were expressed in endothelial cells; however, only MCT1 and MCT4 were present in glial cells. In neurons, MCT2 was localized at the cell membrane whereas MCT1 was detected within mitochondria. Previous studies demonstrated that hypoxia modified GLUT and MCT expression in mammalian brain cells, which was mediated by the transcription factor, hypoxia inducible factor-1. Similarly, we observed that hypoxia modified MCT1 cellular distribution and MCT4 expression in shark telencephalic area and brain stem, confirming the role of these transporters in hypoxia adaptation. Finally, using three-dimensional ultrastructural microscopy, the interaction between glial end-feet and leaky blood vessels of shark brain was assessed in the present study. These data suggested that the brains of shark may take up glucose from blood using a different mechanism than that used by mammalian brains, which may induce astrocyte-neuron lactate shuttling and metabolic coupling as observed in mammalian brain. Our data suggested that the structural conditions and expression patterns of GLUT1, MCT1, MCT2 and MCT4 in shark brain may establish the molecular foundation of metabolic coupling between glia and neurons.
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Affiliation(s)
- Carolina Balmaceda-Aguilera
- Laboratory of Neurobiology and Stem Cells, Department of Cellular Biology, University of Concepcion, Concepción, Chile
| | - Christian Cortés-Campos
- Laboratory of Cellular Biology, Department of Cellular Biology, University of Concepcion, Concepción, Chile
| | - Manuel Cifuentes
- Department of Cellular Biology, Genetics and Physiology, Faculty of Sciences, Malaga University, Málaga, Spain
| | - Bruno Peruzzo
- Anatomy, Histology and Pathology Institute, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Lauren Mack
- Laboratory of Neurobiology and Stem Cells, Department of Cellular Biology, University of Concepcion, Concepción, Chile
| | - Juan Carlos Tapia
- Departments of Biochemistry and Molecular Biophysics and Neuroscience, Columbia University, New York, New York, United States of America
| | - Karina Oyarce
- Laboratory of Neurobiology and Stem Cells, Department of Cellular Biology, University of Concepcion, Concepción, Chile
| | - María Angeles García
- Laboratory of Cellular Biology, Department of Cellular Biology, University of Concepcion, Concepción, Chile
| | - Francisco Nualart
- Laboratory of Neurobiology and Stem Cells, Department of Cellular Biology, University of Concepcion, Concepción, Chile
- * E-mail:
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27
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Babikian T, Prins ML, Cai Y, Barkhoudarian G, Hartonian I, Hovda DA, Giza CC. Molecular and physiological responses to juvenile traumatic brain injury: focus on growth and metabolism. Dev Neurosci 2010; 32:431-41. [PMID: 21071915 DOI: 10.1159/000320667] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 08/20/2010] [Indexed: 01/14/2023] Open
Abstract
Traumatic brain injury (TBI), one of the most frequent causes of neurologic and neurobehavioral morbidity in the pediatric population, can result in lifelong challenges not only for patients, but also for their families. Survivors of a brain injury experienced during childhood - when the brain is undergoing a period of rapid development - frequently experience unique challenges as the consequences of their injuries are overlaid on normal developmental changes. Experimental studies have significantly advanced our understanding of the mechanisms and underlying molecular underpinnings of the injury response and recovery process following a TBI in the developing brain. In this paper, normal and TBI-related alterations in growth, development and metabolism are comprehensively reviewed in the postweanling/juvenile age range in the rat (postnatal days 21-60). As part of this review, TBI-related changes in gene expression are presented, with a focus on the injury-induced alterations related to cerebral growth and metabolism, and discussed in the context of existing literature related to physiological and behavioral responses to experimental TBI. Increasing evidence from the existing literature and from our own gene microarray data indicates that molecular responses related to growth, development and metabolism may play a particularly important role in the injury response and the recovery trajectory following developmental TBI. While gene expression analysis shows many of these changes occur at the level of transcription, a comprehensive review of other studies suggests that the control of metabolic substrates may preferentially be regulated through changes in transporters and enzymatic activity. The interrelation between cellular metabolism and activity-dependent neuroplasticity shows great promise as an area for future study for an optimal translation of experimental data to clinical TBI, with the ultimate goal of guiding therapeutic interventions.
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Affiliation(s)
- Talin Babikian
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, Calif., USA
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28
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ATP-sensitive potassium channel-mediated lactate effect on orexin neurons: implications for brain energetics during arousal. J Neurosci 2010; 30:8061-70. [PMID: 20554857 DOI: 10.1523/jneurosci.5741-09.2010] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Active neurons have a high demand for energy substrate, which is thought to be mainly supplied as lactate by astrocytes. Heavy lactate dependence of neuronal activity suggests that there may be a mechanism that detects and controls lactate levels and/or gates brain activation accordingly. Here, we demonstrate that orexin neurons can behave as such lactate sensors. Using acute brain slice preparations and patch-clamp techniques, we show that the monocarboxylate transporter blocker alpha-cyano-4-hydroxycinnamate (4-CIN) inhibits the spontaneous activity of orexin neurons despite the presence of extracellular glucose. Furthermore, fluoroacetate, a glial toxin, inhibits orexin neurons in the presence of glucose but not lactate. Thus, orexin neurons specifically use astrocyte-derived lactate. The effect of lactate on firing activity is concentration dependent, an essential characteristic of lactate sensors. Furthermore, lactate disinhibits and sensitizes these neurons for subsequent excitation. 4-CIN has no effect on the activity of some arcuate neurons, indicating that lactate dependency is not universal. Orexin neurons show an indirect concentration-dependent sensitivity to glucose below 1 mm, responding by hyperpolarization, which is mediated by ATP-sensitive potassium channels composed of Kir6.1 and SUR1 subunits. In conclusion, our study suggests that lactate is a critical energy substrate and a regulator of the orexin system. Together with the known effects of orexins in inducing arousal, food intake, and hepatic glucose production, as well as lactate release from astrocytes in response to neuronal activity, our study suggests that orexin neurons play an integral part in balancing brain activity and energy supply.
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29
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Shin YJ, Park JH, Choi JS, Chun MH, Moon YW, Lee MY. Enhanced expression of the sweet taste receptors and alpha-gustducin in reactive astrocytes of the rat hippocampus following ischemic injury. Neurochem Res 2010; 35:1628-34. [PMID: 20596769 DOI: 10.1007/s11064-010-0223-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2010] [Indexed: 10/19/2022]
Abstract
The heterodimeric sweet taste receptors, T1R2 and T1R3, have recently been proposed to be associated with the brain glucose sensor. To identify whether sweet taste signaling is regulated in response to an ischemic injury inducing acute impairment of glucose metabolism, we investigated the spatiotemporal expression of the sweet taste receptors and their associated taste-specific G-protein α-gustducin in the rat hippocampus after ischemia. The expression profiles of both receptor subunits and α-gustducin shared overlapping expression patterns in sham-operated and ischemic hippocampi. Constitutive expression of both receptors and α-gustducin was localized in neurons of the pyramidal cell and granule cell layers, but their upregulation was detected in reactive astrocytes in ischemic hippocampi. Immunoblot analysis confirmed the immmunohistochemically determined temporal patterns of sweet-taste signaling proteins. These results suggest that the expression of sweet taste signaling proteins in astrocytes might be regulated in response to altered extracellular levels of glucose following an ischemic insult.
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Affiliation(s)
- Yoo-Jin Shin
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea
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30
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Ngan AK, Wang YS. Tissue-specific transcriptional regulation of monocarboxylate transporters (MCTs) during short-term hypoxia in zebrafish (Danio rerio). Comp Biochem Physiol B Biochem Mol Biol 2009; 154:396-405. [DOI: 10.1016/j.cbpb.2009.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 08/11/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
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31
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Moreira TJTP, Pierre K, Maekawa F, Repond C, Cebere A, Liljequist S, Pellerin L. Enhanced cerebral expression of MCT1 and MCT2 in a rat ischemia model occurs in activated microglial cells. J Cereb Blood Flow Metab 2009; 29:1273-83. [PMID: 19401710 DOI: 10.1038/jcbfm.2009.50] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Monocarboxylate transporters (MCTs) are essential for the use of lactate, an energy substrate known to be overproduced in brain during an ischemic episode. The expression of MCT1 and MCT2 was investigated at 48 h of reperfusion from focal ischemia induced by unilateral extradural compression in Wistar rats. Increased MCT1 mRNA expression was detected in the injured cortex and hippocampus of compressed animals compared to sham controls. In the contralateral, uncompressed hemisphere, increases in MCT1 mRNA level in the cortex and MCT2 mRNA level in the hippocampus were noted. Interestingly, strong MCT1 and MCT2 protein expression was found in peri-lesional macrophages/microglia and in an isolectin B4+/S100beta+ cell population in the corpus callosum. In vitro, MCT1 and MCT2 protein expression was observed in the N11 microglial cell line, whereas an enhancement of MCT1 expression by tumor necrosis factor-alpha (TNF-alpha) was shown in these cells. Modulation of MCT expression in microglia suggests that these transporters may help sustain microglial functions during recovery from focal brain ischemia. Overall, our study indicates that changes in MCT expression around and also away from the ischemic area, both at the mRNA and protein levels, are a part of the metabolic adaptations taking place in the brain after ischemia.
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32
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Lara FA, Kahn SA, da Fonseca AC, Bahia CP, Pinho JP, Graca-Souza AV, Houzel JC, de Oliveira PL, Moura-Neto V, Oliveira MF. On the fate of extracellular hemoglobin and heme in brain. J Cereb Blood Flow Metab 2009; 29:1109-20. [PMID: 19337276 DOI: 10.1038/jcbfm.2009.34] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intracerebral hemorrhage (ICH) is a major cause of disability in adults worldwide. The pathophysiology of this syndrome is complex, involving both inflammatory and redox components triggered by the extravasation of blood into the cerebral parenchyma. Hemoglobin, heme, and iron released therein seem be important in the brain damage observed in ICH. However, there is a lack of information concerning hemoglobin traffic and metabolism in brain cells. Here, we investigated the fate of hemoglobin and heme in cultured neurons and astrocytes, as well as in the cortex of adult rats. Hemoglobin was made traceable by conjugation to Alexa 488, whereas a fluorescent heme analogue (tin-protoporphyrin IX) was prepared to allow heme tracking. Using fluorescence microscopy we observed that neurons were more efficient in uptake hemoglobin and heme than astrocytes. Exposure of cortical neurons to hemoglobin or heme resulted in an oxidative stress condition. Viability assays showed that neurons were more susceptible to both hemoglobin and heme toxicity than astrocytes. Together, these results show that neurons, rather than astrocytes, preferentially take up hemoglobin-derived products, indicating that these cells are actively involved in the ICH-associated brain damage.
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Affiliation(s)
- Flavio A Lara
- Laboratório de Morfogênese Celular, Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil.
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33
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Alessandri B, Gugliotta M, Levasseur JE, Bullock MR. Lactate and glucose as energy substrates and their role in traumatic brain injury and therapy. FUTURE NEUROLOGY 2009. [DOI: 10.2217/14796708.4.2.209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Traumatic brain injury is a leading cause of disability and mortality worldwide, but no new pharmacological treatments are clinically available. A key pathophysiological development in the understanding of traumatic brain injury is the energy crisis derived from decreased cerebral blood flow, increased energy demand and mitochondrial dysfunction. Although still controversial, new findings suggest that brain cells try to cope in these conditions by metabolizing lactate as an energy substrate ‘on-demand’ in lieu of glucose. Experimental and clinical data suggest that lactate, at least when exogenously administered, is transported from astrocytes to neurons for neuronal utilization, essentially bypassing the slow, catabolizing glycolysis process to quickly and efficiently produce ATP. Treatment strategies using systemically applied lactate have proved to be protective in various experimental traumatic brain injury studies. However, lactate has the potential to elevate oxygen consumption to high levels and, therefore, could potentially impose a danger for tissue-at-risk with low cerebral blood flow. The present review outlines the experimental basis of lactate in energy metabolism under physiological and pathophysiological conditions and presents arguments for lactate as a new therapeutical tool in human head injury.
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Affiliation(s)
- Beat Alessandri
- Johannes Gutenberg University, Institute for Neurosurgical Pathophysiology, Langenbeckstrasse 1, D-55131 Mainz, Germany
| | - Marinella Gugliotta
- Department of Neurosurgery, University Hospital of Lausanne (CHUV), Lausanne, Switzerland
| | - Joseph E Levasseur
- Department of Neurosurgery, VCU Medical Center, PO Box 980631, Richmond, VA 23298, USA
| | - M Ross Bullock
- Department of Neurosurgery, University of Miami Miller School of Medicine, Lois Pope LIFE Center, Room 3–20, 1095 NW 14th Terrace, Miami, FL 33136, USA
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34
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Gibbs ME, Rodricks CL, Hutchinson DS, Summers RJ, Miller SL. Importance of adrenergic receptors in prenatally induced cognitive impairment in the domestic chick. Int J Dev Neurosci 2008; 27:27-35. [PMID: 19027843 DOI: 10.1016/j.ijdevneu.2008.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Revised: 10/16/2008] [Accepted: 10/29/2008] [Indexed: 11/30/2022] Open
Abstract
In the domestic chick, mild hypoxia (24h of 14% oxygen) at two stages of embryonic development results in post-hatch memory deficiencies tested using a discriminated bead avoidance task. The nature of the memory loss depends on the gestational age at which the hypoxia occurs. Hypoxia on embryonic day 10 (E10) of a 21 day incubation results in chicks with no short-term memory 10 min after training, whereas hypoxia on day 14 (E14) results in chicks with good labile memory 30 min after training but no consolidation of memory into permanent storage (120 min). Hypoxia at E14 is associated with increased plasma levels of noradrenaline and therefore we suggest that altered catecholamine exposure within the brain contributes to cognitive problems by modifying the responsiveness of brain beta-adrenoceptors. In ovo administration of noradrenaline, or the beta(2)-adrenoceptor agonist formoterol, at E14 had the same effect on memory consolidation as hypoxia. Following hypoxia at E14, memory could be rescued after training by central injection of a beta(3)-adrenoceptor agonist, but not by a beta(2)-adrenoceptor agonist. The differences in the responsiveness of memory processing to beta(2)-adrenoceptor agonists suggests alterations to the receptors or downstream of the receptor activation. However, both types of beta-adrenoceptor agonists rescued memory in E10 treated chicks implying that at this age hypoxia does not affect the receptors. In summary, hypoxia or increased levels of stress hormones during incubation alters beta-adrenoceptor responsiveness; the outcome of the insult depends upon the cellular developmental processes at a given embryonic stage.
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Affiliation(s)
- Marie E Gibbs
- Department of Anatomy & Developmental Biology, Monash University, Wellington Road, Clayton, 3800 Victoria, Australia.
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35
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Vemula S, Roder KE, Yang T, Bhat GJ, Thekkumkara TJ, Abbruscato TJ. A functional role for sodium-dependent glucose transport across the blood-brain barrier during oxygen glucose deprivation. J Pharmacol Exp Ther 2008; 328:487-95. [PMID: 18981287 DOI: 10.1124/jpet.108.146589] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the current study, we determined the functional significance of sodium-dependent/-independent glucose transporters at the neurovasculature during oxygen glucose deprivation (OGD). Confluent brain endothelial cells cocultured with astrocytes were exposed to varying degrees of in vitro stroke conditions. Glucose transporter (GLUT) 1 and sodium glucose cotransporter (SGLT) activity were investigated by luminal membrane uptake and transport studies using [(3)H]D-glucose and also by [(14)C]alpha-methyl D-glucopyranoside (AMG), a specific, nonmetabolized substrate of SGLT. In vivo middle cerebral artery occlusion experiments were tested to determine whether blood-brain barrier (BBB) SGLT activity was induced during ischemia. Increases in luminal D-glucose and AMG uptake and transport were observed with in vitro stroke conditions. Specific inhibitor experiments suggest a combined role for both SGLT and GLUT1 at the BBB during OGD. A time-dependent increase in the uptake of AMG was also seen in mice exposed to permanent focal ischemia, and this increase was sensitive to the SGLT inhibitor, phlorizin. Infarct and edema ratio during ischemia were significantly decreased by the inhibition of this transporter. These results show that both GLUT1 and SGLT play a role at the BBB in the blood-to-brain transport of glucose during ischemic conditions, and inhibition of SGLT during stroke has the potential to improve stroke outcome. Pharmacological modulation of this novel BBB transporter could prove to be a brain vascular target in stroke.
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Affiliation(s)
- Sharanya Vemula
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas 79016, USA
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36
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Schmid-Brunclik N, Bürgi-Taboada C, Antoniou X, Gassmann M, Ogunshola OO. Astrocyte responses to injury: VEGF simultaneously modulates cell death and proliferation. Am J Physiol Regul Integr Comp Physiol 2008; 295:R864-73. [PMID: 18614764 DOI: 10.1152/ajpregu.00536.2007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypoxia is linked to changes in blood-brain barrier (BBB) permeability, and loss of BBB integrity is characteristic of many pathological brain diseases including stroke. In particular, astrocytes play a central role in brain homeostasis and BBB function. We investigated how hypoxia affects astrocyte survival and assessed whether VEGF release through hypoxia-inducible factor-1alpha (HIF-1alpha) induction plays a role in tolerance of these cells to insult. Thus primary astrocytes were subjected to normoxic (21% O(2)), hypoxic (1% O(2)), or near-anoxic (<0.1% O(2)) conditions in the presence or absence of glucose. Cell death was significantly initiated after combined oxygen glucose deprivation, and, surprisingly, astrocyte proliferation increased concomitantly. Near anoxic, but not hypoxic, conditions stabilized HIF-1alpha protein and provoked DNA binding activity, whereas oxygen and glucose deprivation accelerated HIF-1alpha accumulation. Unexpectedly, Hif-1alpha knockdown studies showed that elevated VEGF levels following increased insult was only partially due to HIF-1alpha induction, suggesting alternative mechanisms of VEGF regulation. Notably, endogenous VEGF signaling during insult was essential for cell fate since VEGF inhibition appreciably augmented cell death and reduced proliferation. These data suggest Hif-1 only partially contributes to VEGF-mediated astrocyte responses during chronic injury (as occurs in clinical hypoxic/ischemic insults) that may ultimately be responsible for disrupting BBB integrity.
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Affiliation(s)
- Nicole Schmid-Brunclik
- Institute of Veterinary Physiology, Vetsuisse Faculty, Univ. of Zurich, Winterthurerstrasse 260, Zurich CH 8057, Switzerland
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Obrenovitch TP. Molecular physiology of preconditioning-induced brain tolerance to ischemia. Physiol Rev 2008; 88:211-47. [PMID: 18195087 DOI: 10.1152/physrev.00039.2006] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ischemic tolerance describes the adaptive biological response of cells and organs that is initiated by preconditioning (i.e., exposure to stressor of mild severity) and the associated period during which their resistance to ischemia is markedly increased. This topic is attracting much attention because preconditioning-induced ischemic tolerance is an effective experimental probe to understand how the brain protects itself. This review is focused on the molecular and related functional changes that are associated with, and may contribute to, brain ischemic tolerance. When the tolerant brain is subjected to ischemia, the resulting insult severity (i.e., residual blood flow, disruption of cellular transmembrane gradients) appears to be the same as in the naive brain, but the ensuing lesion is substantially reduced. This suggests that the adaptive changes in the tolerant brain may be primarily directed against postischemic and delayed processes that contribute to ischemic damage, but adaptive changes that are beneficial during the subsequent test insult cannot be ruled out. It has become clear that multiple effectors contribute to ischemic tolerance, including: 1) activation of fundamental cellular defense mechanisms such as antioxidant systems, heat shock proteins, and cell death/survival determinants; 2) responses at tissue level, especially reduced inflammatory responsiveness; and 3) a shift of the neuronal excitatory/inhibitory balance toward inhibition. Accordingly, an improved knowledge of preconditioning/ischemic tolerance should help us to identify neuroprotective strategies that are similar in nature to combination therapy, hence potentially capable of suppressing the multiple, parallel pathophysiological events that cause ischemic brain damage.
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Affiliation(s)
- Tihomir Paul Obrenovitch
- Division of Pharmacology, School of Life Sciences, University of Bradford, Bradford, United Kingdom.
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Abstract
The developing central nervous system has the capacity to metabolize ketone bodies. It was once accepted that on weaning, the 'post-weaned/adult' brain was limited solely to glucose metabolism. However, increasing evidence from conditions of inadequate glucose availability or increased energy demands has shown that the adult brain is not static in its fuel options. The objective of this review is to summarize the body of literature specifically regarding cerebral ketone metabolism at different ages, under conditions of starvation and after various pathologic conditions. The evidence presented supports the following findings: (1) there is an inverse relationship between age and the brain's capacity for ketone metabolism that continues well after weaning; (2) neuroprotective potentials of ketone administration have been shown for neurodegenerative conditions, epilepsy, hypoxia/ischemia, and traumatic brain injury; and (3) there is an age-related therapeutic potential for ketone as an alternative substrate. The concept of cerebral metabolic adaptation under various physiologic and pathologic conditions is not new, but it has taken the contribution of numerous studies over many years to break the previously accepted dogma of cerebral metabolism. Our emerging understanding of cerebral metabolism is far more complex than could have been imagined. It is clear that in addition to glucose, other substrates must be considered along with fuel interactions, metabolic challenges, and cerebral maturation.
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Affiliation(s)
- Mayumi L Prins
- 1UCLA Division of Neurosurgery, Los Angeles, California 90095, USA.
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Amemiya H, Matsuzaka K, Kokubu E, Ohta S, Inoue T. Cellular responses of rat periodontal ligament cells under hypoxia and re-oxygenation conditions in vitro. J Periodontal Res 2007; 43:322-7. [PMID: 18086167 DOI: 10.1111/j.1600-0765.2007.01032.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND OBJECTIVE The aim of this study was to investigate the responses of periodontal ligament cells under hypoxia and re-oxygenation conditions in vitro. MATERIAL AND METHODS Periodontal ligament fibroblasts were isolated from rat incisors. In the hypoxia group, cells were incubated in 2% O(2) for 1-3 d. In the re-oxygenation group, cells were first incubated under the same conditions as the hypoxia group for 24 h and then were returned to normoxic conditions and cultured for 1-2 additional days. RESULTS Proliferation ratios increased in all groups in a time-dependent manner. Proliferation ratios in both the hypoxia and re-oxygenation groups were significantly higher than in the control group on days 2 and 3. Alkaline phosphatase activity was significantly higher in the hypoxia group than in the control and the re-oxygenation groups. The expression of bone sialoprotein mRNA was significantly higher in the hypoxia group than in the control group on days 1 and 2. The expression of vascular endothelial growth factor mRNA was significantly higher in the hypoxia group than in the control group on days 1 and 2. In the re-oxygenation group, the level of expression of bone sialoprotein mRNA and vascular endothelial growth factor mRNA were similar to those of the control group. The expression of heat shock protein 70 mRNA in the hypoxia group was similar to that in the control group, whereas in the re-oxygenation group it was statistically higher than in the other groups. CONCLUSION These results suggest that periodontal ligament cells maintain their osteogenic ability in hypoxia and re-oxygenation conditions in vitro.
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Affiliation(s)
- H Amemiya
- Department of Clinical Pathophysiology, Tokyo Dental College, Chiba, Japan
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Bevensee MO, Boron WF. Effects of acute hypoxia on intracellular-pH regulation in astrocytes cultured from rat hippocampus. Brain Res 2007; 1193:143-52. [PMID: 18190894 DOI: 10.1016/j.brainres.2007.12.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 12/03/2007] [Accepted: 12/03/2007] [Indexed: 11/28/2022]
Abstract
We used the pH-sensitive dye BCECF to evaluate the effect of acute (5-10 min) hypoxia (approximately 3% O(2)) on the regulation of intracellular pH (pH(i)) in astrocyte populations cultured from rat hippocampus. For cells in the nominal absence of CO(2)/HCO(3)(-) at an extracellular pH of 7.40 (37 degrees C), acute hypoxia caused a small (0.05) decrease in steady-state pH(i), but increased the pH(i) recovery rate from an acid load during all but the late phase of the pH(i) recovery. During such pH(i) recoveries, the total acid extrusion rate (phi(E), the product of dpH(i)/dt and proton buffering power) decreased with increasing pH(i). Hypoxia alkali shifted the plot of phi(E) vs. pH(i); over the upper approximately 85% of the phi(E) range, this shift was 0.15-0.30. Hypoxia also stimulated the pH(i) recovery rate from an alkali load. Under normoxic conditions, switching the extracellular buffer to 5% CO(2)/22 mM HCO(-)(3) also alkali shifted the phi(E)-pH(i) plot (upper approximately 85%) by 0.4-0.5. Superimposing hypoxia on CO(2)/HCO(-)(3) further alkali shifted the phi(E)-pH(i) plot (upper approximately 85% of the phi(E) range) by 0.05-0.15. The SITS-insensitive component of phi(E) was alkali shifted by 0.20-0.30, whereas the SITS-sensitive component of phi(E) was depressed in the low pH(i) range. Thus, in the nominal absence of CO(2)/HCO(3)(-), acute hypoxia has little effect on steady-state pH(i) but stimulates acid extrusion and acid loading, whereas in the presence of CO(2)/HCO(-)(3), hypoxia stimulates the SITS-insensitive but inhibits the SITS-sensitive acid extrusion.
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Affiliation(s)
- Mark O Bevensee
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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