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Ran QQ, Chen HL, Liu YL, Yu HX, Shi F, Wang MS. Electroacupuncture preconditioning attenuates ischemic brain injury by activation of the adenosine monophosphate-activated protein kinase signaling pathway. Neural Regen Res 2015; 10:1069-75. [PMID: 26330828 PMCID: PMC4541236 DOI: 10.4103/1673-5374.160095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 01/16/2023] Open
Abstract
Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui (GV20) acupoint for 30 minutes at 1 mA and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase α (AMPKα) and phosphorylated AMPKα was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation.
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Affiliation(s)
- Qiang-Qiang Ran
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Huai-Long Chen
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Yan-Li Liu
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Hai-Xia Yu
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Fei Shi
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Ming-Shan Wang
- Department of Anesthesiology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
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Hang L, Thundyil J, Lim KL. Mitochondrial dysfunction and Parkinson disease: a Parkin-AMPK alliance in neuroprotection. Ann N Y Acad Sci 2015; 1350:37-47. [DOI: 10.1111/nyas.12820] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Liting Hang
- Neurodegeneration Research Laboratory; National Neuroscience Institute; Singapore
- NUS Graduate School for Integrative Sciences and Engineering; Singapore
| | - John Thundyil
- Neurodegeneration Research Laboratory; National Neuroscience Institute; Singapore
| | - Kah-Leong Lim
- Neurodegeneration Research Laboratory; National Neuroscience Institute; Singapore
- NUS Graduate School for Integrative Sciences and Engineering; Singapore
- Neuroscience and Behavioral Disorders Program; Duke-NUS Graduate Medical School; Singapore
- Department of Physiology; National University of Singapore; Singapore
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Ramamurthy S, Ronnett GV. Developing a head for energy sensing: AMP-activated protein kinase as a multifunctional metabolic sensor in the brain. J Physiol 2006; 574:85-93. [PMID: 16690704 PMCID: PMC1817796 DOI: 10.1113/jphysiol.2006.110122] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The 5'-adenosine monophosphate-activated protein kinase (AMPK) is a metabolic and stress sensor that has been functionally conserved throughout eukaryotic evolution. Activation of the AMPK system by various physiological or pathological stimuli that deplete cellular energy levels promotes activation of energy restorative processes and inhibits energy consumptive processes. AMPK has a prominent role not only as a peripheral sensor of energy balance, but also in the CNS as a multifunctional metabolic sensor. Recent work suggests that AMPK plays an important role in maintaining whole body energy balance by coordinating feeding behaviour through the hypothalamus in conjunction with peripheral energy expenditure. In addition, brain AMPK is activated by energy-poor conditions induced by hypoxia, starvation, and ischaemic stroke. Under these conditions, AMPK is activated as a protective response in an attempt to restore cellular homeostasis. However in vivo, it appears that the overall consequence of activation of AMPK is more complex than previously imagined, in that over-activation may be deleterious rather than neuroprotective. This review discusses recent findings that support the role of AMPK in brain as a multidimensional energy sensor and the consequences of its activation or inhibition under physiological and pathological states.
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Affiliation(s)
- Santosh Ramamurthy
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Gotoh J, Itoh Y, Kuang TY, Cook M, Law MJ, Sokoloff L. Negligible glucose-6-phosphatase activity in cultured astroglia. J Neurochem 2000; 74:1400-8. [PMID: 10737595 DOI: 10.1046/j.1471-4159.2000.0741400.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-Deoxy[14C]glucose-6-phosphate (2-[14C]DG-6-P) dephosphorylation and glucose-6-phosphatase (G-6-Pase) activity were examined in cultured rat astrocytes under conditions similar to those generally used in assays of glucose utilization. Astrocytes were loaded with 2-[14C]DG-6-P by preincubation for 15 min in medium containing 2 mM glucose and 50 microM 2-deoxy[14C]glucose (2-[14C]DG). The medium was then replaced with identical medium including 2 mM glucose but lacking 2-[14C]DG, and incubation was resumed for 5 min to diminish residual free 2-[14C]DG levels in the cells by either efflux or phosphorylation. The medium was again replaced with fresh 2-[14C]DG-free medium, and the incubation was continued for 5, 15, or 30 min. Intracellular and extracellular 14C contents were measured at each time point, and the distribution of 14C between 2-[14C]DG and 2-[14C]DG-6-P was characterized by paper chromatography. The results showed little if any hydrolysis of 2-[14C]DG-6-P or export of free 2-[14C]DG from cells to medium; there were slightly increasing losses of 2-[14C]DG and 2-[14C]DG-6-P into the medium with increasing incubation time, but they were in the same proportions found in the cells, suggesting they were derived from nonadherent or broken cells. Experiments carried out with medium lacking glucose during the assay for 2-deoxyglucose-6-phosphatase activity yielded similar results. Evidence for G-6-Pase activity was also sought by following the selective detritiation of glucose from the 2-C position when astrocytes were incubated with [2-3H]glucose and [U-14C]glucose in the medium. No change in the 3H/14C ratio was found in incubations for as long as 15 min. These results indicate negligible G-6-Pase activity in cultured astrocytes.
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Affiliation(s)
- J Gotoh
- Laboratory of Cerebral Metabolism, National Institute of Mental Health, Bethesda, Maryland, USA
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Turnley AM, Stapleton D, Mann RJ, Witters LA, Kemp BE, Bartlett PF. Cellular distribution and developmental expression of AMP-activated protein kinase isoforms in mouse central nervous system. J Neurochem 1999; 72:1707-16. [PMID: 10098881 DOI: 10.1046/j.1471-4159.1999.721707.x] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The mammalian AMP-activated protein kinase is a heterotrimeric serine/threonine protein kinase with multiple isoforms for each subunit (alpha, beta, and gamma) and is activated under conditions of metabolic stress. It is widely expressed in many tissues, including the brain, although its expression pattern throughout the CNS is unknown. We show that brain mRNA levels for the alpha2 and beta2 subunits were increased between embryonic days 10 and 14, whereas expression of alpha1, beta1, and gamma1 subunits was consistent at all ages examined. Immunostaining revealed a mainly neuronal distribution of all isoforms. The alpha2 catalytic subunit was highly expressed in neurons and activated astrocytes, whereas the alpha1 catalytic subunit showed low expression in neuropil. The gamma1 noncatalytic subunit was highly expressed by neurons, but not by astrocytes. Expression of the beta1 and beta2 noncatalytic subunits varied, but some neurons, such as granule cells of olfactory bulb, did not express detectable levels of either beta isoform. Preferential nuclear localization of the alpha2, beta1, and gamma1 subunits suggests new functions of the AMP-activated protein kinase, and the different expression patterns and cellular localization between the two catalytic subunits alpha1 and alpha2 point to different physiological roles.
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Affiliation(s)
- A M Turnley
- The Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia
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Abstract
The hypothalamus and cortex from ob/ob mice and their lean littermates were sonicated and then incubated with glucose-6-phosphate (glucose-6-P) and glycerol phosphate (glycerol-P). The difference between the rates of hydrolysis of glucose-6-P and glycerol-P was taken as the measure of glucose-6-phosphatase activity. The activity was much higher in the hypothalamus from ob/ob mice versus their lean littermates. Activity was undetected in the cortex. These findings raise the possibility that a defect in the regulation of glucose-6-phosphatase activity in a portion of the hypothalamus may relate to the mechanism underlying obesity in the ob/ob mouse. However, obese gene product administration to ob/ob mice, while reducing the body weight, did not alter the glucose-6-phosphatase activity.
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Affiliation(s)
- A Khan
- Department of Molecular Medicine, Karolinska Hospital, Stockholm, Sweden
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Bell JE, Hume R, Busuttil A, Burchell A. Immunocytochemical detection of the microsomal glucose-6-phosphatase in human brain astrocytes. Neuropathol Appl Neurobiol 1993; 19:429-35. [PMID: 8278026 DOI: 10.1111/j.1365-2990.1993.tb00465.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Using an antibody raised against the catalytic subunit of glucose-6-phosphatase, this enzyme was immunolocalized in many astrocytes in 20 normal human brains. Double immunofluorescence studies showed co-localization of glial fibrillary acidic protein (GFAP) with glucose-6-phosphatase in astrocytes. However, not all GFAP-positive cells were also glucose-6-phosphatase positive, indicating that some astrocytes do not contain demonstrable expression of this enzyme. Reactive astrocytes in a variety of abnormal brains were strongly glucose-6-phosphatase positive, but neoplastic astrocytes were often only weakly positive. Expression of the enzyme could not be demonstrated in radial glia, neurons or oligodendroglia. Astrocytes normally contain glycogen and the demonstration that some astrocytes also contain glucose-6-phosphatase indicates that they are competent for both glycogenolysis and gluconeogenesis, which may be critical for neuronal welfare.
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Affiliation(s)
- J E Bell
- Department of Pathology, University of Edinburgh
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Dringen R, Gebhardt R, Hamprecht B. Glycogen in astrocytes: possible function as lactate supply for neighboring cells. Brain Res 1993; 623:208-14. [PMID: 8221102 DOI: 10.1016/0006-8993(93)91429-v] [Citation(s) in RCA: 430] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In order to contribute to the elucidation of the function of astrocyte glycogen in brain, studies on the fate of the glucosyl residues of glycogen were carried out on astroglia-rich primary cultures derived from the brains of newborn rats. On glucose deprivation astroglial cells rapidly deplete their glycogen. In contrast to the situation with hepatocytes, only lactate, but not glucose, is detectable in the medium surrounding the astroglial cells. Besides glucose, astroglial cultures can also use mannose as a substrate for the synthesis of glycogen and the generation of lactate. Although mannose-fed astroglial cells contain glucose-6-phosphate, they do not release a measurable amount of glucose into the culture medium. Instead of glucose the astroglial cells release high amounts of lactate into the culture medium. Gluconolactone or 2-deoxyglucose which prevent glycogen breakdown in astroglial cells after glucose deprivation, allow to discriminate between lactate generated from glycogen and lactate from other sources. The amount of lactate found in the medium in the absence of gluconolactone (or 2-deoxyglucose) exceeds the amount found in the presence of either compound by the lactate equivalents calculated to be contained in the cellular glycogen. In conclusion, glycogen in astrocytes can be considered as a store for lactate rather than for glucose.
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Affiliation(s)
- R Dringen
- Physiologisch-chemisches Institut der Universität, Tübingen Germany
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Burchell A, Waddell ID. The molecular basis of the hepatic microsomal glucose-6-phosphatase system. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1092:129-37. [PMID: 1850300 DOI: 10.1016/0167-4889(91)90146-o] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A Burchell
- Dundee University Medical School, Ninewells Hospital, U.K
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Duncan GE, Brüstle O, Heiss C, Breese GR, Stumpf WE. Topographical assessment of accumulated radioactivity from [14C]2-deoxyglucose and [6(-14C)]glucose in rat forebrain at different survival periods. Neuroscience 1989; 32:813-22. [PMID: 2601848 DOI: 10.1016/0306-4522(89)90301-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The uptake and retention of radioactivity was measured in discrete areas of rat brain at different times after i.v. injection of [14C]2-deoxyglucose or [6(-14)C]glucose, in unrestrained rats. In most brain regions, the accumulation of radioactivity from the two compounds was similar when a 30-min survival period for [6(-14)C]glucose was compared to a 45-min survival period for [14C]2-deoxyglucose. However, at those times, autoradiographic images of the hippocampus and piriform cortex appeared distinctly different for [14C]2-deoxyglucose and [6(-14)C]glucose. Relatively more radioactivity accumulated from [14C]2-deoxyglucose, compared to [14C]glucose, in the stratum lacunosum-moleculare of the hippocampus and in layer 4 of the isocortex. In contrast, relatively more radioactivity accumulated from [6(-14)C]glucose, compared to [14C]2-deoxyglucose, in the molecular and granule cell layers of the dentate gyrus, the CA1 pyramidal cell layer of the hippocampus, and in layer 2 of the piriform cortex. When rats were killed 5 min after injection of [6(-14)C]glucose, the relative neuroanatomical distribution of radioactivity was similar to the 30-min survival period, except in layer 4 of the isocortex, where relatively more radioactivity was present at the early time. When rats were killed 5 min after injection of [14C]2-deoxyglucose, in 20 of 24 brain regions examined, the absolute and relative amounts of accumulated radioactivity were similar when compared to that of the 45-min survival period. In contrast, the absolute and relative amounts of radioactivity were significantly greater for the 5-min compared to the 45-min survival period, in the CA1 pyramidal cell field, dentate gyrus, and layer 2 of the piriform cortex. For those regions, the appearance of autoradiograms prepared from rats killed 5 min after administration of [14C]2-deoxyglucose is remarkably similar to the appearance of autoradiograms prepared from rats killed 5 or 30 min after injection of [6(-14)C]glucose. Possible mechanisms are discussed to explain the observed differences in the accumulation of radioactivity in discrete brain regions after injection of [6(-14)C]glucose and [14C]2-deoxyglucose at the different survival times examined.
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Affiliation(s)
- G E Duncan
- Department of Cell Biology and Anatomy, Biological Sciences Research Center, University of North Carolina, Chapel Hill, 27599
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