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Ohki EC, Langan TJ, Rodgers KR, Chou RC. Non-aggregated Aβ25-35 Upregulates Primary Astrocyte Proliferation In Vitro. Front Cell Neurosci 2017; 11:301. [PMID: 29033790 PMCID: PMC5626946 DOI: 10.3389/fncel.2017.00301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 09/11/2017] [Indexed: 12/25/2022] Open
Abstract
Amyloid beta (Aβ) is a peptide cleaved from amyloid precursor protein that contributes to the formation of senile plaques in Alzheimer’s disease (AD). The relationship between Aβ and astrocyte proliferation in AD remains controversial. Despite pathological findings of increased astrocytic mitosis in AD brains, in vitro studies show an inhibitory effect of Aβ on astrocyte proliferation. In this study, we determined the effect of an active fragment of Aβ (Aβ25-35) on the cell cycle progression of primary rat astrocytes. We found that Aβ25-35 (0.3–1.0 μg/ml) enhanced astrocyte proliferation in vitro in a time- and concentration-dependent manner. Increased DNA synthesis by Aβ25-35 was observed during the S phase of the astrocyte cell cycle, as indicated by proliferation kinetics and bromodeoxyuridine immunocytochemical staining. Aggregation of Aβ25-35 abolished the upregulatory effect of Aβ on astrocyte proliferation. Further examination indicated that Aβ25-35 affected astrocyte proliferation during early or mid-G1 phase but had no effect on DNA synthesis at the peak of S phase. These results provide insight into the relationship between Aβ25-35 and astrocyte cell cycling in AD.
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Affiliation(s)
- Elise C Ohki
- Department of Interdisciplinary Natural Sciences, Roswell Park Cancer Institute, State University of New York at Buffalo, Buffalo, NY, United States
| | - Thomas J Langan
- Departments of Neurology, Pediatrics, and Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, United States.,Hunter James Kelly Research Institute, New York State Center of Excellence Bioinformatics & Life Sciences, Buffalo, NY, United States
| | - Kyla R Rodgers
- Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Richard C Chou
- Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States.,Section of Rheumatology, Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
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Girn HRS, Ahilathirunayagam S, Mavor AID, Homer-Vanniasinkam S. Reperfusion Syndrome: Cellular Mechanisms of Microvascular Dysfunction and Potential Therapeutic Strategies. Vasc Endovascular Surg 2016; 41:277-93. [PMID: 17704330 DOI: 10.1177/1538574407304510] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Reperfusion injury is the paradoxical and complex phenomenon of exacerbation of cellular dysfunction and increase in cell death after the restoration of blood flow to previously ischemic tissues. It involves biochemical and cellular changes causing oxidant production and complement activation, which culminates in an inflammatory response, mediated by neutrophil and platelet cell interactions with the endothelium and among the cells themselves. The mounted inflammatory response has both local and systemic manifestations. Despite improvements in imaging, interventional techniques, and pharmacological agents, morbidity from reperfusion remains high. Extensive research has furthered the understanding of the various pathophysiological mechanisms involved and the development of potential therapeutic strategies. Preconditioning has emerged as a powerful method of ameliorating ischemia reperfusion injury to the myocardium and in transplant surgery. More recently, postconditioning has been shown to provide a therapeutic counter to vasoocclusive emergencies. More research and well-designed trials are needed to bridge the gap between experimental evidence and clinical implementation.
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Lancaster TS, Jefferson SJ, Korzick DH. Local delivery of a PKCε-activating peptide limits ischemia reperfusion injury in the aged female rat heart. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1242-9. [PMID: 21880866 DOI: 10.1152/ajpregu.00851.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reduced efficacy of cardioprotective interventions in the aged female heart, including estrogen replacement, highlights the need for alternative therapeutics to reduce myocardial ischemia-reperfusion (I/R) injury in postmenopausal women. Here, we sought to determine the efficacy of protein kinase-Cε (PKCε)-mediated cardioprotection in the aged, estradiol-deficient rat heart. Infarct size and functional recovery were assessed in Langendorff-perfused hearts from adult (5 mo) or aged (23 mo) female Fisher 344 ovary-intact or ovariectomized (OVX) rats administered a PKCε-activator, receptor for activated C kinase (ψεRACK) prior to 47-min ischemia and 60-min reperfusion. Proteomic analysis was conducted on left ventricular mitochondrial fractions treated with ψεRACK prior to I/R, utilizing isobaric tags for relative and absolute quantitation (iTRAQ) 8plex labeling and tandem mass spectrometry. Real-time PCR was utilized to assess connexin 43 (Cx43) and RACK2 mRNA post-I/R. Greater infarct size in aged OVX (78%) vs. adult (37%) was reduced by ψεRACK (35%, P < 0.0001) and associated with greater mitochondrial PKCε localization (P < 0.0003). Proteomic analysis revealed three novel mitochondrial targets of PKCε-mediated cardioprotection with aging (P < 0.05): the antioxidant enzymes glutathione peroxidase (GPX) and MnSOD2, and heat shock protein 10. Finally, decreased levels of Cx43 and RACK2 mRNA seen with age were partially abrogated by administration of ψεRACK (P < 0.05). The mechanisms described here may represent important therapeutic candidates for the treatment of acute myocardial infarction in postmenopausal women and age-associated estradiol deficiency.
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Affiliation(s)
- T S Lancaster
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Hong IH, Ji H, Hwa SY, Jeong WI, Jeong DH, Do SH, Kim JM, Ki MR, Park JK, Goo MJ, Hwang OK, Hong KS, Han JY, Chung HY, Jeong KS. The protective effect of ENA Actimineral resource A on CCl4-induced liver injury in rats. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2011; 13:462-473. [PMID: 20922552 DOI: 10.1007/s10126-010-9317-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 09/14/2010] [Indexed: 05/29/2023]
Abstract
ENA Actimineral Resource A (ENA-A) is alkaline water that is composed of refined edible cuttlefish bone and two different species of seaweed, Phymatolithon calcareum and Lithothamnion corallioides. In the present study, ENA-A was investigated as an antioxidant to protect against CCl(4)-induced oxidative stress and hepatotoxicity in rats. Liver injury was induced by either subacute or chronic CCl(4) administration, and the rats had free access to tap water mixed with 0% (control group) or 10% (v/v) ENA-A for 5 or 8 weeks. The results of histological examination and measurement of antioxidant activity showed that the reactive oxygen species production, lipid peroxidation, induction of CYP2E1 were decreased and the antioxidant activity, including glutathione and catalase production, was increased in the ENA-A groups as compared with the control group. On 2-DE gel analysis of the proteomes, 13 differentially expressed proteins were obtained in the ENA-A groups as compared with the control group. Antioxidant proteins, including glutathione S-transferase, kelch-like ECH-associated protein 1, and peroxiredoxin 1, were increased with hepatocyte nuclear factor 3-beta and serum albumin precursor, and kininogen precursor decreased more in the ENA-A groups than compared to the control group. In conclusion, our results suggest that ENA-A does indeed have some protective capabilities against CCl(4)-induced liver injury through its antioxidant function.
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Affiliation(s)
- Il-Hwa Hong
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 702-701, Republic of Korea
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Drews G, Krippeit-Drews P, Düfer M. Oxidative stress and beta-cell dysfunction. Pflugers Arch 2010; 460:703-18. [PMID: 20652307 DOI: 10.1007/s00424-010-0862-9] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 06/23/2010] [Accepted: 06/25/2010] [Indexed: 12/11/2022]
Abstract
Diabetes mellitus type 1 and 2 (T1DM and T2DM) are complex multifactorial diseases. Loss of beta-cell function caused by reduced secretory capacity and enhanced apoptosis is a key event in the pathogenesis of both diabetes types. Oxidative stress induced by reactive oxygen and nitrogen species is critically involved in the impairment of beta-cell function during the development of diabetes. Because of their low antioxidant capacity, beta-cells are extremely sensitive towards oxidative stress. In beta-cells, important targets for an oxidant insult are cell metabolism and K(ATP) channels. The oxidant-evoked alterations of K(ATP) channel activity seem to be critical for oxidant-induced dysfunction because genetic ablation of K(ATP) channels attenuates the effects of oxidative stress on beta-cell function. Besides the effects on metabolism, interference of oxidants with mitochondria induces key events in apoptosis. Consequently, increasing antioxidant defence is a promising strategy to delay beta cell failure in (pre)-diabetic patients or during islet transplantation. Knock-out of K(ATP) channels has beneficial effects on oxidant-induced inhibition of insulin secretion and cell death. Interestingly, these effects can be mimicked by sulfonylureas that have been used in the treatment of T2DM for many years. Loss of functional K(ATP) channels leads to up-regulation of antioxidant enzymes, a process that depends on cytosolic Ca(2+). These observations are of great importance for clinical intervention because they show a possibility to protect beta-cells at an early stage before dramatic changes of the secretory capacity and loss of cell mass become manifest and lead to glucose intolerance or even overt diabetes.
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Affiliation(s)
- Gisela Drews
- Department of Pharmacology and Clinical Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, Germany.
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Gier B, Krippeit-Drews P, Sheiko T, Aguilar-Bryan L, Bryan J, Düfer M, Drews G. Suppression of KATP channel activity protects murine pancreatic beta cells against oxidative stress. J Clin Invest 2009; 119:3246-56. [PMID: 19805912 DOI: 10.1172/jci38817] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 07/29/2009] [Indexed: 12/21/2022] Open
Abstract
The enhanced oxidative stress associated with type 2 diabetes mellitus contributes to disease pathogenesis. We previously identified plasma membrane-associated ATP-sensitive K+ (KATP) channels of pancreatic beta cells as targets for oxidants. Here, we examined the effects of genetic and pharmacologic ablation of KATP channels on loss of mouse beta cell function and viability following oxidative stress. Using mice lacking the sulfonylurea receptor type 1 (Sur1) subunit of KATP channels, we found that, compared with insulin secretion by WT islets, insulin secretion by Sur1-/- islets was less susceptible to oxidative stress induced by the oxidant H2O2. This was likely, at least in part, a result of the reduced ability of H2O2 to hyperpolarize plasma membrane potential and reduce cytosolic free Ca2+ concentration ([Ca2+]c) in the Sur1-/- beta cells. Remarkably, Sur1-/- beta cells were less prone to apoptosis induced by H2O2 or an NO donor than WT beta cells, despite an enhanced basal rate of apoptosis. This protective effect was attributed to upregulation of the antioxidant enzymes SOD, glutathione peroxidase, and catalase. Upregulation of antioxidant enzymes and reduced sensitivity of Sur1-/- cells to H2O2-induced apoptosis were mimicked by treatment with the sulfonylureas tolbutamide and gliclazide. Enzyme upregulation and protection against oxidant-induced apoptosis were abrogated by agents lowering [Ca2+]c. Sur1-/- mice were less susceptible than WT mice to streptozotocin-induced beta cell destruction and subsequent hyperglycemia and death, which suggests that loss of KATP channel activity may protect against streptozotocin-induced diabetes in vivo.
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Affiliation(s)
- Belinda Gier
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Tübingen, Germany
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Salvi M, Battaglia V, Brunati AM, La Rocca N, Tibaldi E, Pietrangeli P, Marcocci L, Mondovì B, Rossi CA, Toninello A. Catalase takes part in rat liver mitochondria oxidative stress defense. J Biol Chem 2007; 282:24407-15. [PMID: 17576767 DOI: 10.1074/jbc.m701589200] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Highly purified rat liver mitochondria (RLM) when exposed to tert-butylhydroperoxide undergo matrix swelling, membrane potential collapse, and oxidation of glutathione and pyridine nucleotides, all events attributable to the induction of mitochondrial permeability transition. Instead, RLM, if treated with the same or higher amounts of H2O2 or tyramine, are insensitive or only partially sensitive, respectively, to mitochondrial permeability transition. In addition, the block of respiration by antimycin A added to RLM respiring in state 4 conditions, or the addition of H2O2, results in O2 generation, which is blocked by the catalase inhibitors aminotriazole or KCN. In this regard, H2O2 decomposition yields molecular oxygen in a 2:1 stoichiometry, consistent with a catalytic mechanism with a rate constant of 0.0346 s(-1). The rate of H2O2 consumption is not influenced by respiratory substrates, succinate or glutamate-malate, nor by N-ethylmaleimide, suggesting that cytochrome c oxidase and the glutathione-glutathione peroxidase system are not significantly involved in this process. Instead, H2O2 consumption is considerably inhibited by KCN or aminotriazole, indicating activity by a hemoprotein. All these observations are compatible with the presence of endogenous heme-containing catalase with an activity of 825 +/- 15 units, which contributes to mitochondrial protection against endogenous or exogenous H2O2. Mitochondrial catalase in liver most probably represents regulatory control of bioenergetic metabolism, but it may also be proposed for new therapeutic strategies against liver diseases. The constitutive presence of catalase inside mitochondria is demonstrated by several methodological approaches as follows: biochemical fractionating, proteinase K sensitivity, and immunogold electron microscopy on isolated RLM and whole rat liver tissue.
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Affiliation(s)
- Mauro Salvi
- Dipartimento di Chimica Biologica, Università di Padova, Viale G. Colombo 3, 35121 Padova
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