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Title: On the nature of the Cu-rich aggregates in brain astrocytes

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1405056
Grant/Contract Number:
AC02-06CH11357; P41 GM103622
Resource Type:
Journal Article: Published Article
Journal Name:
Redox Biology
Additional Journal Information:
Journal Volume: 11; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-26 17:06:26; Journal ID: ISSN 2213-2317
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Sullivan, Brendan, Robison, Gregory, Osborn, Jenna, Kay, Martin, Thompson, Peter, Davis, Katherine, Zakharova, Taisiya, Antipova, Olga, and Pushkar, Yulia. On the nature of the Cu-rich aggregates in brain astrocytes. Netherlands: N. p., 2017. Web. doi:10.1016/j.redox.2016.12.007.
Sullivan, Brendan, Robison, Gregory, Osborn, Jenna, Kay, Martin, Thompson, Peter, Davis, Katherine, Zakharova, Taisiya, Antipova, Olga, & Pushkar, Yulia. On the nature of the Cu-rich aggregates in brain astrocytes. Netherlands. doi:10.1016/j.redox.2016.12.007.
Sullivan, Brendan, Robison, Gregory, Osborn, Jenna, Kay, Martin, Thompson, Peter, Davis, Katherine, Zakharova, Taisiya, Antipova, Olga, and Pushkar, Yulia. Sat . "On the nature of the Cu-rich aggregates in brain astrocytes". Netherlands. doi:10.1016/j.redox.2016.12.007.
@article{osti_1405056,
title = {On the nature of the Cu-rich aggregates in brain astrocytes},
author = {Sullivan, Brendan and Robison, Gregory and Osborn, Jenna and Kay, Martin and Thompson, Peter and Davis, Katherine and Zakharova, Taisiya and Antipova, Olga and Pushkar, Yulia},
abstractNote = {},
doi = {10.1016/j.redox.2016.12.007},
journal = {Redox Biology},
number = C,
volume = 11,
place = {Netherlands},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.redox.2016.12.007

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  • Fulfilling a bevy of biological roles, copper is an essential metal for healthy brain function. Cu dyshomeostasis has been demonstrated to be involved in some neurological conditions including Menkes and Alzheimer’s diseases. We have previously reported localized Cu-rich aggregates in astrocytes of the subventricular zone (SVZ) in rodent brains with Cu concentrations in the hundreds of millimolar. Metallothionein, a cysteine-rich protein critical to metal homeostasis and known to participate in a variety of neuroprotective and neuroregenerative processes, was proposed as a binding protein. Here, we present an analysis of metallothionein(1,2) knockout (MTKO) mice and age-matched controls using X-ray fluorescence microscopy.more » In large structures such as the corpus callosum, cortex, and striatum, there is no significant difference in Cu, Fe, or Zn concentrations in MTKO mice compared to age-matched controls. In the astrocyte-rich subventricular zone where Cu-rich aggregates reside, approximately 1/3 as many Cu-rich aggregates persist in MTKO mice resulting in a decrease in periventricular Cu concentration. Aggregates in both wild-type and MTKO mice show XANES spectra characteristic of CuxSy multimetallic clusters and have similar [S]/[Cu] ratios. Consistent with assignment as a CuxSy multimetallic cluster, the astrocyte-rich SVZ of both MTKO and wild-type mice exhibit autofluorescent bodies, though MTKO mice exhibit fewer. Furthermore, XRF imaging of Au-labeled lysosomes and ubiquitin demonstrates a lack of co-localization with Cu-rich aggregates suggesting they are not involved in a degradation pathway. Overall, these data suggest that Cu in aggregates is bound by either metallothionein-3 or a yet unknown protein similar to metallothionein.« less
  • Since malate is known to play an important role in a variety of functions in the brain including energy metabolism, the transfer of reducing equivalents and possibly metabolic trafficking between different cell types; a series of biochemical determinations were initiated to evaluate the rate of 14CO2 production from L-(U-14C)malate in rat brain astrocytes. The 14CO2 production from labeled malate was almost totally suppressed by the metabolic inhibitors rotenone and antimycin A suggesting that most of malate metabolism was coupled to the electron transport system. A double reciprocal plot of the 14CO2 production from the metabolism of labeled malate revealed biphasicmore » kinetics with two apparent Km and Vmax values suggesting the presence of more than one mechanism of malate metabolism in these cells. Subsequent experiments were carried out using 0.01 mM and 0.5 mM malate to determine whether the addition of effectors would differentially alter the metabolism of high and low concentrations of malate. Effectors studied included compounds which could be endogenous regulators of malate metabolism and metabolic inhibitors which would provide information regarding the mechanisms regulating malate metabolism. Both lactate and aspartate decreased 14CO2 production from malate equally. However, a number of effectors were identified which selectively altered the metabolism of 0.01 mM malate including aminooxyacetate, furosemide, N-acetylaspartate, oxaloacetate, pyruvate and glucose, but had little or no effect on the metabolism of 0.5 mM malate. In addition, alpha-ketoglutarate and succinate decreased 14CO2 production from 0.01 mM malate much more than from 0.5 mM malate. In contrast, a number of effectors altered the metabolism of 0.5 mM malate more than 0.01 mM. These included methionine sulfoximine, glutamate, malonate, alpha-cyano-4-hydroxycinnamate and ouabain.« less
  • Purified astrocyte cultures from neonatal rat cerebrum respond to isoproterenol, a ..beta..-adrenergic agonist, with a transient rise in cAMP production. This astroglial property was regulated by serum, a chemically defined medium (serum-free medium plus hydrocortisone, putrescine, prostaglandin F/sub 2/, insulin, and fibroblast growth factor) and epidermal growth factor. Compared to astrocytes grown in serum-supplemented medium, astrocytes grown in the chemically defined medium were nonresponsive to isoproterenol stimulation, and this difference did not appear to be due to selection of a subpopulation of cells by either medium. The data suggest that a decreased ..beta..-adrenergic receptor number and an increased degradation ofmore » cAMP may account for the reduced response to ..beta..-adrenergic stimulation. The nonresponsive state of astrocytes in the defined medium was reversible when the medium was replaced with serum-supplemented medium. An active substance(s) in serum was responsible for restoring the responsiveness of astrocytes. Each of the five components of the defined medium had little effect by itself; however, together they acted synergistically to desensitize astrocytes to ..beta..-adrenergic stimulation. On the other hand, epidermal growth factor, a potent mitogen for astrocytes, was very competent by itself in reducing the cAMP response of astrocytes to ..beta..-adrenergic stimulation. Thus purified astrocytes grown in the chemically defined medium appear to be a good model for the study of hormonal interactions and of serum factors which may modulate the ..beta..-adrenergic response.« less
  • Both neurons and astrocytes contain specific receptors for angiotensin II (AII). The authors used selective ligands for the AT{sub 1} and AT{sub 2} types of AII receptors to investigate the expression of functional receptor subtypes in astrocyte cultures and neuron cultures from 1-day-old (neonatal) rat brain. In astrocyte cultures, competition of {sup 125}I-labeled AII ({sup 125}I-AII) specific binding with AT{sub 1} (DuP753) or AT{sub 2} {l brace}PD123177, CGP42112A, (Phe(p-NH{sub 2}){sup 6})AII{r brace} selective receptor ligands revealed a potency series of AII > DuP753 > > > CGP42112A > (Phe(p-NH{sub 2}){sup 6})AII > PD123177. These results suggest a predominance of themore » AT{sub 1} receptor subtype in neonatal astrocytes. {sup 125}I-AII specific binding to neonate neuronal cultures was reduced 73-84% by 1 {mu} MPD123177, and the residual {sup 125}I-AII specific binding was eliminated by DuP753. The results suggest that astrocyte cultures from neonatal rat brains contain predominantly AT{sub 1} receptors that are coupled to a stimulation of inositophospholipid hydrolysis. In contrast, neuron cultures from neonatal rat brain contain mostly AT{sub 2} receptors that are coupled to a reduction in basal cGMP levels, but a smaller population of AT{sub 1} receptors is also present in these neurons.« less
  • The present study investigates angiotensin (Ang) II effects on secretory protein synthesis in brain astrocytes cultured from neonatal and 21-day-old rats. Ang II-induced changes in the de novo synthesis of (35S)methionine-labeled secretory proteins were visualized using two-dimensional NaDodSO4/PAGE. Astrocytes from 21-day-old rat brain possess specific high-affinity receptors for Ang II. These cells express two Ang II-induced secretory proteins with Mr 55,000 (AISP-55K) and Mr 30,000 (AISP-30K), which were time- and dose-dependent (EC50, 1 nM). (Sar1, Ile8)Ang II (where Sar is sarcosine) inhibited Ang II-induced secretion of AISP-55K but not AISP-30K. N-terminal amino acid sequencing indicates that AISP-55K is identical tomore » rat plasminogen activator inhibitor 1, whereas AISP-30K exhibits 72-81% identity to three closely related proteins: human tissue inhibitor of metalloproteases, a rat phorbol ester-induced protein, and the murine growth-responsive protein 16C8. Immunofluorescent staining with rat plasminogen activator inhibitor 1 antibody was induced in the majority of cells in culture after Ang II treatment of astrocytes from 21-day-old rat brains. Absence of this response to Ang II in astrocytes from neonatal rat brain provides evidence that this action of Ang II on astrocytes is developmentally regulated.« less