51
|
Wu Z, Zhao Y, Zhao B. Superoxide anion, uncoupling proteins and Alzheimer's disease. J Clin Biochem Nutr 2010; 46:187-94. [PMID: 20490313 PMCID: PMC2872223 DOI: 10.3164/jcbn.09-104-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 11/27/2009] [Indexed: 12/31/2022] Open
Abstract
Superoxide anion is the first generated reactive oxygen species (ROS) after oxygen enters living cells. It was once considered to be highly deleterious to cell functions and aging. Therefore, antioxidants were suggested to prevent aging and degenerative diseases. However, superoxide signaling has been shown in many physiological responses such as transcriptional regulation, protein activation, bioenergy output, cell proliferation and apoptosis. The uncoupling proteins (UCPs) are a family of mitochondrial anion-carrier proteins located in the inner mitochondrial membrane and are considered to reduce the generation of superoxide anion through the mitochondrial mild uncoupling. UCPs are important in prevention of mitochondrial excessive generation of ROS, transfer of mitochondrial substrates, mitochondrial calcium uniport and regulation of thermogenesis. Superoxide anion and uncoupling proteins are linked to Alzheimer's disease in mitochondria. Simultaneous disorders of superoxide and uncoupling proteins create the conditions for neuronal oxidative damages. On the one hand, sustained oxidative damage causes neuronal apoptosis and eventually, accumulated neuronal apoptosis, leading to exacerbations of Alzheimer's disease. On the other hand, our study has shown that UCP2 and UCP4 have important impact on mitochondrial calcium concentration of nerve cells, suggesting that their abnormal expression may involve in the pathogenesis of Alzheimer's disease.
Collapse
Affiliation(s)
- Zhaofei Wu
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Rd., Chaoyang District, Beijing 100101, the People's Republic of China
| | | | | |
Collapse
|
52
|
Mokini Z, Marcovecchio ML, Chiarelli F. Molecular pathology of oxidative stress in diabetic angiopathy: role of mitochondrial and cellular pathways. Diabetes Res Clin Pract 2010; 87:313-21. [PMID: 20022399 DOI: 10.1016/j.diabres.2009.11.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 11/15/2009] [Accepted: 11/24/2009] [Indexed: 02/07/2023]
Abstract
Diabetes mellitus is characterized by chronic hyperglycaemia and a significant risk of developing micro- and macrovascular complications. Growing evidence suggests that increased oxidative stress, induced by several hyperglycaemia-activated pathways, is a key factor in the pathogenesis of endothelial dysfunction and vascular disease. Reactive oxidant molecules, which are produced at a high rate in the diabetic milieu, can cause oxidative damage of many cellular components and activate several pathways linked with inflammation and apoptosis. Among the mechanisms involved in oxidative stress generation, mitochondria and uncoupling proteins are of particular interest and there is growing evidence suggesting their pivotal role in the pathogenesis of diabetic complications. Other important cellular sources of oxidants include nicotinamide adenine dinucleotide phosphate oxidases and uncoupling endothelial nitric oxide synthase. In addition, diabetes is associated with reduced antioxidant defences, which generally contrast the deleterious effect of oxidant species. This concept underlines a potential beneficial role of antioxidant therapy for the prevention and treatment of diabetic vascular disease. However, large scale trials with classical antioxidants have failed to show a significant effect on major cardiovascular events, thus underlying the need of further investigations in order to develop therapies to prevent and/or delay the development of micro- and macrovascular complications.
Collapse
Affiliation(s)
- Zhirajr Mokini
- Department of Paediatrics, University of Chieti, Via Dei Vestini 5, 66100 Chieti, Italy
| | | | | |
Collapse
|
53
|
Chan SL, Wei Z, Chigurupati S, Tu W. Compromised respiratory adaptation and thermoregulation in aging and age-related diseases. Ageing Res Rev 2010; 9:20-40. [PMID: 19800420 DOI: 10.1016/j.arr.2009.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 09/22/2009] [Accepted: 09/23/2009] [Indexed: 02/04/2023]
Abstract
Mitochondrial dysfunction and reactive oxygen species (ROS) production are at the heart of the aging process and are thought to underpin age-related diseases. Mitochondria are not only the primary energy-generating system but also the dominant cellular source of metabolically derived ROS. Recent studies unravel the existence of mechanisms that serve to modulate the balance between energy metabolism and ROS production. Among these is the regulation of proton conductance across the inner mitochondrial membrane that affects the efficiency of respiration and heat production. The field of mitochondrial respiration research has provided important insight into the role of altered energy balance in obesity and diabetes. The notion that respiration and oxidative capacity are mechanistically linked is making significant headway into the field of aging and age-related diseases. Here we review the regulation of cellular energy and ROS balance in biological systems and survey some of the recent relevant studies that suggest that respiratory adaptation and thermodynamics are important in aging and age-related diseases.
Collapse
|
54
|
Smorodchenko A, Rupprecht A, Sarilova I, Ninnemann O, Bräuer AU, Franke K, Schumacher S, Techritz S, Nitsch R, Schuelke M, Pohl EE. Comparative analysis of uncoupling protein 4 distribution in various tissues under physiological conditions and during development. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2309-19. [PMID: 19646951 DOI: 10.1016/j.bbamem.2009.07.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 07/21/2009] [Accepted: 07/23/2009] [Indexed: 11/17/2022]
Abstract
UCP4 is a member of the mitochondrial uncoupling protein subfamily and one of the three UCPs (UCP2, UCP4, UCP5), associated with the nervous system. Its putative functions include thermogenesis, attenuation of reactive oxidative species (ROS), regulation of mitochondrial calcium concentration and involvement in cell differentiation and apoptosis. Here we investigate UCP4's subcellular, cellular and tissue distribution, using an antibody designed specially for this study, and discuss the findings in terms of the protein's possible functions. Western blot and immunohistochemistry data confirmed that UCP4 is expressed predominantly in the central nervous system (CNS), as previously shown at mRNA level. No protein was found in heart, spleen, stomach, intestine, lung, thymus, muscles, adrenal gland, testis and liver. The reports revealing UCP4 mRNA in kidney and white adipose tissue were not confirmed at protein level. The amount of UCP4 varies in the mitochondria of different brain regions, with the highest protein content found in cortex. We show that UCP4 is present in fetal murine brain tissue as early as embryonic days 12-14 (E12-E14), which coincides with the beginning of neuronal differentiation. The UCP4 content in mitochondria decreases as the age of mice increases. UCP4 preferential expression in neurons and its developmental expression pattern under physiological conditions may indicate a specific protein function, e.g. in neuronal cell differentiation.
Collapse
Affiliation(s)
- Alina Smorodchenko
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin, Berlin, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
55
|
A homozygous genetic variant of mitochondrial uncoupling protein 4 exerts protection against the occurrence of multiple sclerosis. Neuromolecular Med 2009; 11:101-5. [PMID: 19536655 DOI: 10.1007/s12017-009-8071-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/31/2009] [Indexed: 01/06/2023]
Abstract
Multiple sclerosis (MS), which results in damage of the white matter at multiple foci, poses a far-reaching public health problem in view of the burden it imposes on the affected young and middle-aged. Some previous data suggested that roles could be played in the demyelinization of the white matter of the brain by the malfunctioning of the mitochondria and mitochondria-associated reactive oxygen species. In this context, we hypothesized that the finely tuned dynamic stability of the mitochondrial membrane potential (MMP), which is the main mirror of the functional state of the mitochondria, is essential for the intact nature of the glia cells in the brain. Setting out from this, our aim in this study was to examine how the rs10807344 and rs2270450 genetic variants of mitochondrial uncoupling protein 4 (mUCP4) can give rise to the development of MS, since mUCP4 is presumed to be of great importance in the regulation of the MMP and cellular energy metabolism. The clinical and genetic data on 120 relapsing-remitting MS patients and 250 neuroimaging alteration-free subjects were analyzed. The rs10807344 CC genotype proved to exert a protective effect against the occurrence of MS (neuroimaging alteration-free controls, 58%; MS group, 33%; P < 0.0000089; OR, 0.32; 95% CI: 0.2-0.56, P < 0.005). The present findings indirectly raise the possibility that a shift or imbalance in the finally regulated MMP plays a role in the development of MS.
Collapse
|
56
|
Trimmer PA, Schwartz KM, Borland MK, De Taboada L, Streeter J, Oron U. Reduced axonal transport in Parkinson's disease cybrid neurites is restored by light therapy. Mol Neurodegener 2009; 4:26. [PMID: 19534794 PMCID: PMC2711937 DOI: 10.1186/1750-1326-4-26] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 06/17/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It has been hypothesized that reduced axonal transport contributes to the degeneration of neuronal processes in Parkinson's disease (PD). Mitochondria supply the adenosine triphosphate (ATP) needed to support axonal transport and contribute to many other cellular functions essential for the survival of neuronal cells. Furthermore, mitochondria in PD tissues are metabolically and functionally compromised. To address this hypothesis, we measured the velocity of mitochondrial movement in human transmitochondrial cybrid "cytoplasmic hybrid" neuronal cells bearing mitochondrial DNA from patients with sporadic PD and disease-free age-matched volunteer controls (CNT). The absorption of low level, near-infrared laser light by components of the mitochondrial electron transport chain (mtETC) enhances mitochondrial metabolism, stimulates oxidative phosphorylation and improves redox capacity. PD and CNT cybrid neuronal cells were exposed to near-infrared laser light to determine if the velocity of mitochondrial movement can be restored by low level light therapy (LLLT). Axonal transport of labeled mitochondria was documented by time lapse microscopy in dopaminergic PD and CNT cybrid neuronal cells before and after illumination with an 810 nm diode laser (50 mW/cm2) for 40 seconds. Oxygen utilization and assembly of mtETC complexes were also determined. RESULTS The velocity of mitochondrial movement in PD cybrid neuronal cells (0.175 +/- 0.005 SEM) was significantly reduced (p < 0.02) compared to mitochondrial movement in disease free CNT cybrid neuronal cells (0.232 +/- 0.017 SEM). For two hours after LLLT, the average velocity of mitochondrial movement in PD cybrid neurites was significantly (p < 0.003) increased (to 0.224 +/- 0.02 SEM) and restored to levels comparable to CNT. Mitochondrial movement in CNT cybrid neurites was unaltered by LLLT (0.232 +/- 0.017 SEM). Assembly of complexes in the mtETC was reduced and oxygen utilization was altered in PD cybrid neuronal cells. PD cybrid neuronal cell lines with the most dysfunctional mtETC assembly and oxygen utilization profiles were least responsive to LLLT. CONCLUSION The results from this study support our proposal that axonal transport is reduced in sporadic PD and that a single, brief treatment with near-infrared light can restore axonal transport to control levels. These results are the first demonstration that LLLT can increase axonal transport in model human dopaminergic neuronal cells and they suggest that LLLT could be developed as a novel treatment to improve neuronal function in patients with PD.
Collapse
Affiliation(s)
- Patricia A Trimmer
- University of Virginia, Morris K Udall Parkinson's Research Center of Excellence and Department of Neurology, Charlottesville, Virginia, USA.
| | | | | | | | | | | |
Collapse
|
57
|
Abstract
Mitochondrial potassium channels are believed to contribute to cytoprotection of injured cardiac and neuronal tissues. The following potassium channels have been described in the inner mitochondrial membrane: the ATP-regulated potassium channel, the large conductance Ca(2+)-activated potassium channel, the voltage-gated Kv1.3 potassium channel, and the twin-pore domain TASK-3 potassium channel. The putative functional roles of these channels include changes in mitochondrial matrix volume, mitochondrial respiration, and membrane potential. In addition, the activity of these channels modulates the generation of reactive oxygen species by mitochondria. In this article, we discuss recent observations on three fundamental issues concerning mitochondrial potassium channels: (i) their molecular identity, (ii) their interaction with potassium channel openers and inhibitors, and (iii) their functional properties.
Collapse
Affiliation(s)
- Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | | | | |
Collapse
|
58
|
|
59
|
Rodriguez-Pallares J, Parga JA, Joglar B, Guerra MJ, Labandeira-Garcia JL. The Mitochondrial ATP-Sensitive Potassium Channel Blocker 5-Hydroxydecanoate Inhibits Toxicity of 6-Hydroxydopamine on Dopaminergic Neurons. Neurotox Res 2009; 15:82-95. [DOI: 10.1007/s12640-009-9010-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/12/2008] [Accepted: 12/17/2008] [Indexed: 12/21/2022]
|
60
|
Abstract
Over the past decade, much progress has been made in understanding the mechanisms of ketogenic diet (KD) action. From the complex systemic and metabolic changes induced by the KD have emerged innovative hypotheses attempting to link biochemical adaptations to its clinical effects. Despite such developments, the fundamental question of how the KD works remains as elusive as ever. At present, it is unclear which of the many potential mechanisms proposed thus far are directly relevant to the clinical effects of the KD. It is unlikely that these numerous hypotheses can be unified into a single mechanism (or a final common pathway). Nevertheless, it may be instructive to consider each of these putative mechanisms in turn and ask the following question: if the mechanism or target in question is a critical determinant of the anticonvulsant efficacy of the KD, then would a similar intervention known to be based on that mechanism yield a comparable effect? Perhaps answering this question for each mechanistic speculation might help substantiate (or invalidate) that particular hypothesis. Can the KD be packaged into a pill? At present, the answer is likely "no." We have yet to discover a "magic bullet" that completely mirrors the anticonvulsant (and potential neuroprotective) effects of the KD. However, without a clearer understanding of the mechanistic elements comprising the complex metabolic puzzle posed by the KD, we would be left only with empiric observations, and to wonder curiously how a high-fat diet can exert such profound clinical effects.
Collapse
Affiliation(s)
- Jong M Rho
- Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85018, USA.
| | | |
Collapse
|
61
|
Yeung CK, Chiang SWY, Chan KP, Pang CP, Lam DSC. Potassium Channel Openers Reduce the Caspase-3 Expression of Triamcinolone-Treated Retinal Pigment Epithelial (ARPE19) Cells. Cutan Ocul Toxicol 2008. [DOI: 10.1080/15569520500371636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
62
|
Mitochondrially mediated plasticity in the pathophysiology and treatment of bipolar disorder. Neuropsychopharmacology 2008; 33:2551-65. [PMID: 18235426 DOI: 10.1038/sj.npp.1301671] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bipolar disorder (BPD) has traditionally been conceptualized as a neurochemical disorder, but there is mounting evidence for impairments of cellular plasticity and resilience. Here, we review and synthesize the evidence that critical aspects of mitochondrial function may play an integral role in the pathophysiology and treatment of BPD. Retrospective database searches were performed, including MEDLINE, abstract booklets, and conference proceedings. Articles were also obtained from references therein and personal communications, including original scientific work, reviews, and meta-analyses of the literature. Material regarding the potential role of mitochondrial function included genetic studies, microarray studies, studies of intracellular calcium regulation, neuroimaging studies, postmortem brain studies, and preclinical and clinical studies of cellular plasticity and resilience. We review these data and discuss their implications not only in the context of changing existing conceptualizations regarding the pathophysiology of BPD, but also for the strategic development of improved therapeutics. We have focused on specific aspects of mitochondrial dysfunction that may have major relevance for the pathophysiology and treatment of BPD. Notably, we discuss calcium dysregulation, oxidative phosphorylation abnormalities, and abnormalities in cellular resilience and synaptic plasticity. Accumulating evidence from microarray studies, biochemical studies, neuroimaging, and postmortem brain studies all support the role of mitochondrial dysfunction in the pathophysiology of BPD. We propose that although BPD is not a classic mitochondrial disease, subtle deficits in mitochondrial function likely play an important role in various facets of BPD, and that enhancing mitochondrial function may represent a critical component for the optimal long-term treatment of the disorder.
Collapse
|
63
|
Kicinska A, Skalska J, Szewczyk A. Mitochondria and Big-Conductance Potassium Channel Openers. Toxicol Mech Methods 2008; 14:63-5. [DOI: 10.1080/15376520490257491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
64
|
Abizaid A, Horvath TL. Brain circuits regulating energy homeostasis. REGULATORY PEPTIDES 2008; 149:3-10. [PMID: 18514925 PMCID: PMC2605273 DOI: 10.1016/j.regpep.2007.10.006] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 10/30/2007] [Indexed: 11/21/2022]
Abstract
Recent years have seen an impetus in the study for central mechanisms regulating energy balance, and caloric intake possibly as a response to the obesity pandemic. This renewed interest as well as drastic improvements in the tools that are now currently available to neuroscientists, has yielded a great deal of insight into the mechanisms by which the brain regulates metabolic function, and volitional aspects of feeding in response to metabolic signals like leptin, insulin and ghrelin. Among these mechanisms are the complex intracellular signals elicited by these hormones in neurons. Moreover, these signals produce and modulate the metabolism of the cell at the level of the mitochondria. Finally, these signals promote plastic changes that alter the synaptic circuitry in a number of circuits and ultimately affect cellular, physiological and behavioral responses in defense of energy homeostasis. These mechanisms are surveyed in this review.
Collapse
Affiliation(s)
- Alfonso Abizaid
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, USA.
| | | |
Collapse
|
65
|
New properties of mitochondrial ATP-regulated potassium channels. J Bioenerg Biomembr 2008; 40:325-35. [DOI: 10.1007/s10863-008-9153-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Accepted: 06/16/2008] [Indexed: 11/25/2022]
|
66
|
Skalska J, Piwońska M, Wyroba E, Surmacz L, Wieczorek R, Koszela-Piotrowska I, Zielińska J, Bednarczyk P, Dołowy K, Wilczynski GM, Szewczyk A, Kunz WS. A novel potassium channel in skeletal muscle mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:651-9. [PMID: 18515063 DOI: 10.1016/j.bbabio.2008.05.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 05/07/2008] [Accepted: 05/12/2008] [Indexed: 11/30/2022]
Abstract
In this work we provide evidence for the potential presence of a potassium channel in skeletal muscle mitochondria. In isolated rat skeletal muscle mitochondria, Ca(2+) was able to depolarize the mitochondrial inner membrane and stimulate respiration in a strictly potassium-dependent manner. These potassium-specific effects of Ca(2+) were completely abolished by 200 nM charybdotoxin or 50 nM iberiotoxin, which are well-known inhibitors of large conductance, calcium-activated potassium channels (BK(Ca) channel). Furthermore, NS1619, a BK(Ca)-channel opener, mimicked the potassium-specific effects of calcium on respiration and mitochondrial membrane potential. In agreement with these functional data, light and electron microscopy, planar lipid bilayer reconstruction and immunological studies identified the BK(Ca) channel to be preferentially located in the inner mitochondrial membrane of rat skeletal muscle fibers. We propose that activation of mitochondrial K(+) transport by opening of the BK(Ca) channel may be important for myoprotection since the channel opener NS1619 protected the myoblast cell line C2C12 against oxidative injury.
Collapse
Affiliation(s)
- Jolanta Skalska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
67
|
Kulawiak B, Kudin AP, Szewczyk A, Kunz WS. BK channel openers inhibit ROS production of isolated rat brain mitochondria. Exp Neurol 2008; 212:543-7. [PMID: 18572168 DOI: 10.1016/j.expneurol.2008.05.004] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 04/23/2008] [Accepted: 05/10/2008] [Indexed: 11/26/2022]
Abstract
To delineate the potential mechanism of neuroprotective effects of potassium channel openers we have investigated, how Ca(2+)-activated large conductance potassium channel (BK(Ca) channel) openers influence the production of reactive oxygen species (ROS) by rat brain mitochondria, since mitochondrial generation of ROS is known to have a crucial influence on neuronal survival. We studied the effects of BK(Ca) channel openers CGS 7184 and NS 1619 on hydrogen peroxide production rate of isolated rat brain mitochondria. In K(+)-containing media 3 microM of both channel openers reduced the hydrogen peroxide production rates by approximately 20%. This effect was not observed in Na(+)-containing media. This potassium-dependent partial inhibition of hydrogen peroxide production was found to be sensitive to the selective blockers of BK(Ca) channel iberiotoxin and charybdotoxin applied in nanomolar concentrations. Taken together, our data are compatible with the viewpoint that the opening of a Ca(2+)-activated large conductance potassium channel being localised in the inner membrane of brain mitochondria inhibits ROS production by respiratory chain complex I. This finding is suggested to explain the beneficial effects of BK potassium channel openers on neuronal survival.
Collapse
Affiliation(s)
- Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
| | | | | | | |
Collapse
|
68
|
Sud N, Wells SM, Sharma S, Wiseman DA, Wilham J, Black SM. Asymmetric dimethylarginine inhibits HSP90 activity in pulmonary arterial endothelial cells: role of mitochondrial dysfunction. Am J Physiol Cell Physiol 2008; 294:C1407-18. [PMID: 18385287 DOI: 10.1152/ajpcell.00384.2007] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased asymmetric dimethylarginine (ADMA) levels have been implicated in the pathogenesis of a number of conditions affecting the cardiovascular system. However, the mechanism(s) by which ADMA exerts its effect has not been adequately elucidated. Thus the purpose of this study was to determine the effect of increased ADMA on nitric oxide (NO) signaling and to begin to elucidate the mechanism by which ADMA acts. Our initial data demonstrated that ADMA increased NO synthase (NOS) uncoupling in both recombinant human endothelial NO synthase (eNOS) and pulmonary arterial endothelial cells (PAEC). Furthermore, we found that this endothelial NOS (eNOS) uncoupling increased 3-nitrotyrosine levels preferentially in the mitochondria of PAEC due to a redistribution of eNOS from the plasma membrane to the mitochondria. This increase in nitration in the mitochondria was found to induce mitochondrial dysfunction as determined by increased mitochondrial-derived reactive oxygen species and decreased generation of ATP. Finally, we found that the decrease in ATP resulted in a reduction in the chaperone activity of HSP90 resulting in a decrease in its interaction with eNOS. In conclusion increased levels of ADMA causes mitochondrial dysfunction and a loss of heat shock protein-90 chaperone activity secondary to an uncoupling of eNOS. Mitochondrial dysfunction may be an understudied component of the endothelial dysfunction associated with various cardiovascular disease states.
Collapse
Affiliation(s)
- Neetu Sud
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
| | | | | | | | | | | |
Collapse
|
69
|
Luo JZ, Luo L. Ginseng on hyperglycemia: effects and mechanisms. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2008; 6:423-7. [PMID: 18955300 PMCID: PMC2781779 DOI: 10.1093/ecam/nem178] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been reported that American ginseng attenuates hyperglycemia and may present itself as a supplement to diabetes therapy. However, the lack of standardization in the usage of ginseng root leads to inconclusive results when applied to diabetes treatment. The mechanisms of American ginseng root in the treatment of diabetes remains a mystery. This greatly limits the effective utilization of American ginseng in facilitating diabetic therapy. Initiating studies have shown that American ginseng increases insulin production and reduces cell death in pancreatic β-cells. Also, studies have revealed American ginseng's ability to decrease blood glucose in type II diabetes patients as well as in streptozotocin-induced diabetic animals (STZ-diabetic mice). These data suggest that effects of ginseng in improving hyperglycemia may alter mitochondrial function as well as apoptosis cascades to ensure cell viability in pancreatic islet cells. This review briefly summarizes current knowledge of ginseng components and clinical studies related to diabetes. Further research will be needed to explore and identify the component(s) of ginseng, which may be responsible for the beneficial effects observed in animal studies which could then be extrapolated to human islets.
Collapse
Affiliation(s)
- John Zeqi Luo
- The Center for Stem Cell Biology, Department of Research, Roger Williams Hospital, Boston University, Medical School, 825 Chalkstone Avenue, Providence, RI, USA.
| | | |
Collapse
|
70
|
UCP-2 and UCP-3 proteins are differentially regulated in pancreatic beta-cells. PLoS One 2008; 3:e1397. [PMID: 18167556 PMCID: PMC2164968 DOI: 10.1371/journal.pone.0001397] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Accepted: 12/10/2007] [Indexed: 11/19/2022] Open
Abstract
Background Increased uncoupling protein-2 (UCP-2) expression has been associated with impaired insulin secretion, whereas UCP-3 protein levels are decreased in the skeleton muscle of type-2 diabetic subjects. In the present studies we hypothesize an opposing effect of glucose on the regulation of UCP-2 and UCP-3 in pancreatic islets. Methodology Dominant negative UCP-2 and wild type UCP-3 adenoviruses were generated, and insulin release by transduced human islets was measured. UCP-2 and UCP-3 mRNA levels were determined using quantitative PCR. UCP-2 and UCP-3 protein expression was investigated in human islets cultured in the presence of different glucose concentrations. Human pancreatic sections were analyzed for subcellular localization of UCP-3 using immunohistochemistry. Principal Findings Dominant negative UCP-2 expression in human islets increased insulin secretion compared to control islets (p<0.05). UCP-3 mRNA is expressed in human islets, but the relative abundance of UCP-2 mRNA was 8.1-fold higher (p<0.05). Immunohistochemical analysis confirmed co-localization of UCP-3 protein with mitochondria in human beta-cells. UCP-2 protein expression in human islets was increased ∼2-fold after high glucose exposure, whereas UCP-3 protein expression was decreased by ∼40% (p<0.05). UCP-3 overexpression improved glucose-stimulated insulin secretion. Conclusions UCP-2 and UCP-3 may have distinct roles in regulating beta-cell function. Increased expression of UCP-2 and decreased expression of UCP-3 in humans with chronic hyperglycemia may contribute to impaired glucose-stimulated insulin secretion. These data imply that mechanisms that suppress UCP-2 or mechanisms that increase UCP-3 expression and/or function are potential therapeutic targets to offset defects of insulin secretion in humans with type-2 diabetes.
Collapse
|
71
|
Zhdanov AV, Ward MW, Prehn JHM, Papkovsky DB. Dynamics of intracellular oxygen in PC12 Cells upon stimulation of neurotransmission. J Biol Chem 2007; 283:5650-61. [PMID: 18086678 DOI: 10.1074/jbc.m706439200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurotransmission, synaptic plasticity, and maintenance of membrane excitability require high mitochondrial activity in neurosecretory cells. Using a fluorescence-based intracellular O2 sensing technique, we investigated the respiration of differentiated PC12 cells upon depolarization with 100 mm K+. Single cell confocal analysis identified a significant depolarization of the plasma membrane potential and a relatively minor depolarization of the mitochondrial membrane potential following K+ exposure. We observed a two-phase respiratory response: a first intense spike lasting approximately 10 min, during which average intracellular O2 was reduced from 85-90% of air saturation to 55-65%, followed by a second wave of smaller amplitude and longer duration. The fast rise in O2 consumption coincided with a transient increase in cellular ATP by approximately 60%, which was provided largely by oxidative phosphorylation and by glycolysis. The increase of respiration was orchestrated mainly by Ca2+ release from the endoplasmic reticulum, whereas the influx of extracellular Ca2+ contributed approximately 20%. Depletion of Ca2+ stores by ryanodine, thapsigargin, and 4-chloro-m-cresol reduced the amplitude of respiratory spike by 45, 63, and 71%, respectively, whereas chelation of intracellular Ca2+ abolished the response. Uncoupling of the mitochondria with the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone amplified the responses to K+; elevated respiration induced a profound deoxygenation without increasing the cellular ATP levels reduced by carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Cleavage of synaptobrevin 2 by tetanus toxin, known to reduce neurotransmission, did not affect the respiratory response to K+, whereas the general excitability of d PC12 cells increased.
Collapse
Affiliation(s)
- Alexander V Zhdanov
- Biochemistry Department, University College Cork, Cavanagh Pharmacy Building, Cork, Ireland
| | | | | | | |
Collapse
|
72
|
Lores-Arnaiz S, Bustamante J, Czernizyniec A, Galeano P, González Gervasoni M, Rodil Martínez A, Paglia N, Cores V, Lores-Arnaiz MR. Exposure to enriched environments increases brain nitric oxide synthase and improves cognitive performance in prepubertal but not in young rats. Behav Brain Res 2007; 184:117-23. [PMID: 17675170 DOI: 10.1016/j.bbr.2007.06.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 06/23/2007] [Accepted: 06/29/2007] [Indexed: 12/26/2022]
Abstract
Rats were randomly assigned to enriched (EE) or standard environments (SE) at 21 or 73 days of age, for 17 days. Half of the rats of each rearing condition were trained in a radial maze (RM). At 38 days (pre-pubertal) or 90 days (young), rats were sacrificed and brain cytosolic and mitochondrial nitric oxide synthase (mtNOS) activity was assayed. Western blot analysis of brain mtNOS was conducted. In the pre-pubertal group, EE rats improved their performance in the RM while SE rats did not. In the young group, SE and EE rats showed a random performance in the RM. In SE pre-pubertal rats, training increased brain cytosolic NOS and mtNOS activity by 68% and 82%. In EE non-trained pre-pubertal rats, brain cytosolic NOS and mtNOS activity increased by 80% and 60%, as compared with SE non-trained pre-pubertal rats. In EE pre-pubertal rats that were trained, brain cytosolic NOS and mtNOS activity increased by 70% and 90%, as compared with SE pre-pubertal rats that were not trained. A higher protein expression of brain mtNOS was found in EE rats, as compared with SE animals. Mitochondrial complex I activity was higher in EE than in SE rats. Training had no effect on complex I activity neither in SE nor in EE rats. In young rats, no significant differences in enzyme activities were found between EE and SE rats. These results support the hypothesis that brief exposure to EE and training produce effects on behavioral performance and on biochemical parameters in an age-dependent manner.
Collapse
Affiliation(s)
- S Lores-Arnaiz
- Laboratory of Free Radical Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
| | | | | | | | | | | | | | | | | |
Collapse
|
73
|
Yudkoff M, Daikhin Y, Melø TM, Nissim I, Sonnewald U, Nissim I. The ketogenic diet and brain metabolism of amino acids: relationship to the anticonvulsant effect. Annu Rev Nutr 2007; 27:415-30. [PMID: 17444813 PMCID: PMC4237068 DOI: 10.1146/annurev.nutr.27.061406.093722] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In many epileptic patients, anticonvulsant drugs either fail adequately to control seizures or they cause serious side effects. An important adjunct to pharmacologic therapy is the ketogenic diet, which often improves seizure control, even in patients who respond poorly to medications. The mechanisms that explain the therapeutic effect are incompletely understood. Evidence points to an effect on brain handling of amino acids, especially glutamic acid, the major excitatory neurotransmitter of the central nervous system. The diet may limit the availability of oxaloacetate to the aspartate aminotransferase reaction, an important route of brain glutamate handling. As a result, more glutamate becomes accessible to the glutamate decarboxylase reaction to yield gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter and an important antiseizure agent. In addition, the ketogenic diet appears to favor the synthesis of glutamine, an essential precursor to GABA. This occurs both because ketone body carbon is metabolized to glutamine and because in ketosis there is increased consumption of acetate, which astrocytes in the brain quickly convert to glutamine. The ketogenic diet also may facilitate mechanisms by which the brain exports to blood compounds such as glutamine and alanine, in the process favoring the removal of glutamate carbon and nitrogen.
Collapse
Affiliation(s)
- Marc Yudkoff
- Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
| | | | | | | | | | | |
Collapse
|
74
|
Sharma S, Sud N, Wiseman DA, Carter AL, Kumar S, Hou Y, Rau T, Wilham J, Harmon C, Oishi P, Fineman JR, Black SM. Altered carnitine homeostasis is associated with decreased mitochondrial function and altered nitric oxide signaling in lambs with pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2007; 294:L46-56. [PMID: 18024721 DOI: 10.1152/ajplung.00247.2007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Utilizing aortopulmonary vascular graft placement in the fetal lamb, we have developed a model (shunt) of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. Our previous studies have identified a progressive development of endothelial dysfunction in shunt lambs that is dependent, at least in part, on decreased nitric oxide (NO) signaling. The purpose of this study was to evaluate the possible role of a disruption in carnitine metabolism in shunt lambs and to determine the effect on NO signaling. Our data indicate that at 2 wk of age, shunt lambs have significantly reduced expression (P < 0.05) of the key enzymes in carnitine metabolism: carnitine palmitoyltransferases 1 and 2 as well as carnitine acetyltransferase (CrAT). In addition, we found that CrAT activity was inhibited due to increased nitration. Furthermore, free carnitine levels were significantly decreased whereas acylcarnitine levels were significantly higher in shunt lambs (P < 0.05). We also found that alterations in carnitine metabolism resulted in mitochondrial dysfunction, since shunt lambs had significantly decreased pyruvate, increased lactate, and a reduced pyruvate/lactate ratio. In pulmonary arterial endothelial cells cultured from juvenile lambs, we found that mild uncoupling of the mitochondria led to a decrease in cellular ATP levels and a reduction in both endothelial NO synthase-heat shock protein 90 (eNOS-HSP90) interactions and NO signaling. Similarly, in shunt lambs we found a loss of eNOS-HSP90 interactions that correlated with a progressive decrease in NO signaling. Our data suggest that mitochondrial dysfunction may play a role in the development of endothelial dysfunction and pulmonary hypertension and increased pulmonary blood flow.
Collapse
Affiliation(s)
- Shruti Sharma
- Program in Pulmonary Disease, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
75
|
Wu Z, Luo JZ, Luo L. American ginseng modulates pancreatic beta cell activities. Chin Med 2007; 2:11. [PMID: 17961234 PMCID: PMC2094710 DOI: 10.1186/1749-8546-2-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 10/25/2007] [Indexed: 11/10/2022] Open
Abstract
The mechanism of the beneficial effects of Panax quinquefolius (Xiyangshen, American ginseng) on diabetes is yet to be elucidated. Recent studies show that Panax quinquefolius increases insulin production and reduces the death of pancreatic beta cells. Mechanism studies indicate that Panax quinquefolius improves cell's immuno-reactivity and mitochondrial function through various factors. Clinical studies show that Panax quinquefolius improves postprandial glycemia in type 2 diabetic patients. Further studies to identify the component(s) of Panax quinquefolius linked with pancreatic islets/beta cells in vitro and in vivo are warranted for better understanding of the full effects of Panax quinquefolius.
Collapse
Affiliation(s)
- Zonggui Wu
- Department of Cardiology, Second Affiliated Hospital, Second Military Medical University, Shanghai, China.
| | | | | |
Collapse
|
76
|
Passos JF, Saretzki G, Ahmed S, Nelson G, Richter T, Peters H, Wappler I, Birket MJ, Harold G, Schaeuble K, Birch-Machin MA, Kirkwood TBL, von Zglinicki T. Mitochondrial dysfunction accounts for the stochastic heterogeneity in telomere-dependent senescence. PLoS Biol 2007; 5:e110. [PMID: 17472436 PMCID: PMC1858712 DOI: 10.1371/journal.pbio.0050110] [Citation(s) in RCA: 520] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 02/20/2007] [Indexed: 12/30/2022] Open
Abstract
Aging is an inherently stochastic process, and its hallmark is heterogeneity between organisms, cell types, and clonal populations, even in identical environments. The replicative lifespan of primary human cells is telomere dependent; however, its heterogeneity is not understood. We show that mitochondrial superoxide production increases with replicative age in human fibroblasts despite an adaptive UCP-2–dependent mitochondrial uncoupling. This mitochondrial dysfunction is accompanied by compromised [Ca2+]i homeostasis and other indicators of a retrograde response in senescent cells. Replicative senescence of human fibroblasts is delayed by mild mitochondrial uncoupling. Uncoupling reduces mitochondrial superoxide generation, slows down telomere shortening, and delays formation of telomeric γ-H2A.X foci. This indicates mitochondrial production of reactive oxygen species (ROS) as one of the causes of replicative senescence. By sorting early senescent (SES) cells from young proliferating fibroblast cultures, we show that SES cells have higher ROS levels, dysfunctional mitochondria, shorter telomeres, and telomeric γ-H2A.X foci. We propose that mitochondrial ROS is a major determinant of telomere-dependent senescence at the single-cell level that is responsible for cell-to-cell variation in replicative lifespan. After a limited number of cell divisions, somatic cells lose the capacity for proliferation, called cellular replicative senescence. Senescence, which is triggered by the loss of DNA sequences at the ends of chromosomes (telomeres), is often seen as an example of a regular “biological clock.” However, cell senescence is heterogeneous, with large differences in lifespan between individual cell lineages. This heterogeneity is clearly related to stress, specifically oxidative stress. It was not known, however, whether stress-induced “premature” senescence involves telomeres or is caused by telomere-independent DNA damage responses. Mitochondria are the most important source of reactive oxygen species (ROS) in cells under physiological conditions. We found that mitochondrial function deteriorated while cells approached senescence, leading to increased ROS production. Delaying mitochondrial dysfunction led to postponed replicative senescence and slowing of telomere shortening. Prematurely senescing cells sorted out of young cultures displayed mitochondrial dysfunction, increased oxidative stress, and short telomeres. We propose that replicative telomere-dependent senescence is not “clocked,” but rather is a stochastic process triggered largely by random mitochondrial dysfunction. Mitochondrial uncoupling is used to study the relationship between telomere length, the production of reactive oxygen species, and replicative senescence.
Collapse
Affiliation(s)
- João F Passos
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Center for Integrated Systems Biology of Ageing and Nutrition, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Gabriele Saretzki
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Crucible Laboratory, Life Knowledge Park, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Shaheda Ahmed
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Crucible Laboratory, Life Knowledge Park, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Glyn Nelson
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Center for Integrated Systems Biology of Ageing and Nutrition, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Torsten Richter
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Heiko Peters
- Institute of Human Genetics, International Centre for Life, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Ilka Wappler
- Institute of Human Genetics, International Centre for Life, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Matthew J Birket
- School of Clinical and Laboratory Sciences, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Graham Harold
- Crucible Laboratory, Life Knowledge Park, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Karin Schaeuble
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Mark A Birch-Machin
- School of Clinical and Laboratory Sciences, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Thomas B. L Kirkwood
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Center for Integrated Systems Biology of Ageing and Nutrition, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Thomas von Zglinicki
- Henry Wellcome Laboratory for Biogerontology Research, Institute for Ageing and Health, University of Newcastle, Newcastle upon Tyne, United Kingdom
- Center for Integrated Systems Biology of Ageing and Nutrition, University of Newcastle, Newcastle upon Tyne, United Kingdom
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
77
|
Bachmann RF, Schloesser RJ, Gould TD, Manji HK. Mood stabilizers target cellular plasticity and resilience cascades: implications for the development of novel therapeutics. Mol Neurobiol 2007; 32:173-202. [PMID: 16215281 DOI: 10.1385/mn:32:2:173] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bipolar disorder is a devastating disease with a lifetime incidence of about 1% in the general population. Suicide is the cause of death in 10 to 15% of patients and in addition to suicide, mood disorders are associated with many other harmful health effects. Mood stabilizers are medications used to treat bipolar disorder. In addition to their therapeutic effects for the treatment of acute manic episodes, mood stabilizers are useful as prophylaxis against future episodes and as adjunctive antidepressant medications. The most established and investigated mood-stabilizing drugs are lithium and valproate but other anticonvulsants (such as carbamazepine and lamotrigine) and antipsychotics are also considered as mood stabilizers. Despite the efficacy of these diverse medications, their mechanisms of action remain, to a great extent, unknown. Lithium's inhibition of some enzymes, such as inositol monophosphatase and glycogen synthase kinase-3, probably results in its mood-stabilizing effects. Valproate may share its anticonvulsant target with its mood-stabilizing target or may act through other mechanisms. It has been shown that lithium, valproate, and/or carbamazepine regulate numerous factors involved in cell survival pathways, including cyclic adenine monophospate response element-binding protein, brain-derived neurotrophic factor, bcl-2, and mitogen-activated protein kinases. These drugs have been suggested to have neurotrophic and neuroprotective properties that ameliorate impairments of cellular plasticity and resilience underlying the pathophysiology of mood disorders. This article also discusses approaches to develop novel treatments specifically for bipolar disorder.
Collapse
Affiliation(s)
- Rosilla F Bachmann
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, MD, USA
| | | | | | | |
Collapse
|
78
|
de la Monte SM, Jhaveri A, Maron BA, Wands JR. Nitric Oxide Synthase 3-Mediated Neurodegeneration After Intracerebral Gene Delivery. J Neuropathol Exp Neurol 2007; 66:272-83. [PMID: 17413318 DOI: 10.1097/nen.0b013e318040cfa2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In Alzheimer disease (AD), increased nitric oxide synthase 3 (NOS3) expression correlates with apoptosis in cortical neurons and colocalizes with amyloid precursor protein (APP)-amyloid beta (Abeta) deposits in the brain. In the present study we examined the potential role of NOS3 in relation to AD-type neurodegeneration using an in vivo model of gene delivery. Long Evans rat pups were given a single intracerebral injection of recombinant plasmid DNA containing the human NOS3 cDNA (p-hNOS3) or the luciferase (p-Luc) gene as a negative control, and complexed with polyamine reagent. Overexpression of NOS3 in the brain increased the levels of APP, APP-Abeta, p53, Tau, glial fibrillary acidic protein, and peroxisome proliferator activated receptors (PPAR) delta and gamma and decreased the levels of Hu (neuronal marker) mRNA, phosphorylated glycogen synthase kinase 3beta, ATP synthase, and choline acetyltransferase expression as demonstrated by real-time quantitative reverse-transcribed polymerase chain reaction, Western blot analysis, or immunohistochemical staining. These effects of NOS3 overexpression were accompanied by increased single-stranded DNA immunoreactivity, reflecting DNA damage. The results suggest that increased cerebral expression of NOS3 causes several molecular abnormalities related to AD-type neurodegeneration, including oxidative stress, mitochondrial dysfunction, and impaired acetylcholine homeostasis. The coexisting increases in PPAR-delta and -gamma expression suggest that the adverse effects of NOS3 overexpression may be abated by PPAR agonist treatment.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Department of Medicine, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA.
| | | | | | | |
Collapse
|
79
|
Van Hoecke M, Prigent-Tessier AS, Garnier PE, Bertrand NM, Filomenko R, Bettaieb A, Marie C, Beley AG. Evidence of HIF-1 functional binding activity to caspase-3 promoter after photothrombotic cerebral ischemia. Mol Cell Neurosci 2006; 34:40-7. [PMID: 17101276 DOI: 10.1016/j.mcn.2006.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/27/2006] [Accepted: 09/29/2006] [Indexed: 01/29/2023] Open
Abstract
Hypoxia-inducible factor 1 alpha (HIF-1alpha) is a transcription factor that was suggested in vitro to promote cell death by modulation of proapoptotic genes. In this report, we tested the hypothesis of an in vivo proapoptotic role of HIF-1alpha after an ischemic insult. For this purpose, HIF-1alpha and procaspase-3 mRNA and protein expressions were examined in rat brain subjected to 12- and 24-h permanent focal ischemia and the presence of an HIF-1 binding activity to the caspase-3 gene promoter was explored. The results showed that HIF-1alpha and procaspase-3 expressions increased with a similar pattern in response to ischemia. In addition, caspase-3 activation was observed in cells that express HIF-1alpha. Moreover, electrophoretic mobility assay revealed a specific HIF-1 binding activity to the caspase-3 gene promoter. Altogether the present data provide strong arguments for a causative relationship between HIF-1alpha and caspase-3 inductions through a functional binding activity to the caspase-3 gene promoter.
Collapse
MESH Headings
- Animals
- Binding Sites/genetics
- Caspase 3/genetics
- Caspase 3/metabolism
- Disease Models, Animal
- Enzyme Activation/genetics
- Gene Expression Regulation, Enzymologic/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/metabolism
- Hypoxia-Ischemia, Brain/genetics
- Hypoxia-Ischemia, Brain/metabolism
- Hypoxia-Ischemia, Brain/physiopathology
- Intracranial Thrombosis/genetics
- Intracranial Thrombosis/metabolism
- Intracranial Thrombosis/physiopathology
- Male
- Oxygen/metabolism
- Promoter Regions, Genetic/genetics
- Protein Binding/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Telencephalon/metabolism
- Telencephalon/physiopathology
Collapse
Affiliation(s)
- Michaël Van Hoecke
- Laboratoire de Pharmacodynamie et Physiologie Pharmaceutique, Faculté de Pharmacie, 7 boulevard Jeanne d'Arc, BP 87900, 21079 Dijon Cedex, France
| | | | | | | | | | | | | | | |
Collapse
|
80
|
Co-regulation of dopamine D1 receptor and uncoupling protein-2 expression in 3-nitropropionic acid-induced neurotoxicity: neuroprotective role of L-carnitine. Neurosci Lett 2006; 410:62-5. [PMID: 17052844 DOI: 10.1016/j.neulet.2006.09.070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 09/25/2006] [Accepted: 09/27/2006] [Indexed: 11/15/2022]
Abstract
This study tested the hypothesis that the expression of uncoupling proteins (UCPs) and dopamine (DA) system genes is responsive to 3-nitropropionic acid (3-NPA) neurotoxic effects and to the neuroprotective effects of the mitochondrial enhancer, L-carnitine (LC), in the rat striatum. Inactivation of mitochondrial succinate dehydrogenase (SDH) by 3-NPA results in hypoxic brain damage. Hypoxic conditions induce uncoupling protein-2 (UCP-2). An increase in UCP-2 expression may lead to a decrease in production of reactive oxygen species (ROS) associated with energy depletion. However, this adaptive response can also lead to a reduction of ATP that may further contribute to energy deficit and mitochondrial dysfunction. Here, male adult Sprague-Dawley rats (n=5/group) were injected either with saline or 3-NPA at 30 mg/kg, s.c. alone or 30 min after pre-treatment with LC (100mg/kg, i.p.). Rectal temperature was monitored before treatment and 4h following 3-NPA administration. Animals were sacrificed 4h post-treatment. Total RNA was isolated from the striatum and transcripts of UCP-2, UCP-4 and UCP-5 genes, as well as genes related to dopamine metabolism, such as DA D(1) and D(2) receptors, tyrosine hydroxylase (TH), monoamine oxidase-B (MAO-B), and vesicular monoamine transporter-2 (VMAT-2), were measured using real-time reverse transcription polymerase chain reaction (RT-PCR). While core temperature decreased significantly in 3-NPA-treated rats, LC significantly inhibited the hypothermic effect of 3-NPA (p<0.05). 3-NPA caused a significant increase in UCP-2 and DA D(1) receptor gene expression in the striatum and both effects were attenuated by pre-treatment with LC. Since LC maintains the ATP/ADP ratio and was previously shown to be neuroprotective against 3-NPA toxicity, the modulation of UCP-2 expression by LC suggests that LC counteracts energy dissipation and thus prevents the negative effects of ATP decline on DA neurotransmission.
Collapse
|
81
|
Nübel T, Ricquier D. Respiration under control of uncoupling proteins: Clinical perspective. HORMONE RESEARCH 2006; 65:300-10. [PMID: 16641553 DOI: 10.1159/000092847] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Indexed: 11/19/2022]
Abstract
The term 'uncoupling protein' was originally used for the mitochondrial membrane protein UCP1, which is uniquely present in mitochondria of brown adipocytes, thermogenic cells that regulate body temperature in small rodents, hibernators and mammalian newborns. In these cells, UCP1 acts as a proton carrier activated by free fatty acids and creates a shunt between complexes of the respiratory chain and ATP-synthase resulting in a futile proton cycling and dissipation of oxidation energy as heat. Recent identification of new homologues to UCP1 expressed in brown and white adipose tissue, muscle, brain and other tissues together with the hypothesis that these novel uncoupling proteins (UCPs) may regulate thermogenesis and/or fatty acid metabolism and furthermore may protect against free radical oxygen species production have generated considerable optimism for rapid advances in the identification of new targets for pharmacological management of complex pathological syndromes such as obesity, type 2 diabetes or chronic inflammatory diseases. However, since the physiological and biochemical roles of the novel UCPs are not yet clear, the main challenge today consists first of all in providing mechanistic explanation for their functions in cellular physiology. This lively awaited information may be the basis for potential pharmacological targeting of the UCPs in future.
Collapse
Affiliation(s)
- T Nübel
- Centre National de la Recherche Scientifique, Unit 9078, Faculty of Medicine René Descartes Paris 5, Paris, France
| | | |
Collapse
|
82
|
Passos JF, von Zglinicki T. Mitochondria, telomeres and cell senescence. Exp Gerontol 2006; 40:466-72. [PMID: 15963673 DOI: 10.1016/j.exger.2005.04.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 04/14/2005] [Accepted: 04/14/2005] [Indexed: 01/21/2023]
Abstract
The accumulation of oxidative damage is one of the most widely accepted causes of ageing. Mitochondrial dysfunction, in particular damage to the mitochondrial DNA has been hypothesised, more than thirty years ago, as responsible for increased production of reactive oxygen species (ROS) and, thus, as one possible causal factor for ageing. There is now a wealth of data that supports this hypothesis, which is mostly derived from models considering the ageing of post-mitotic or slowly dividing cells in vivo. One major cellular model of ageing, however, is replicative senescence, the irreversible loss of division potential of somatic cells after a more or less constant number of cell divisions. Not much data exists concerning the role of mitochondria in this model. Here, we review evidence supporting an involvement of mitochondria in replicative senescence and a possible link to telomere shortening.
Collapse
Affiliation(s)
- João F Passos
- Henry Wellcome Laboratory for Biogerontology Research, Newcastle University, Newcastle NE4 6BE, UK
| | | |
Collapse
|
83
|
Gáspár T, Kis B, Snipes JA, Lenzsér G, Mayanagi K, Bari F, Busija DW. Transient glucose and amino acid deprivation induces delayed preconditioning in cultured rat cortical neurons. J Neurochem 2006; 98:555-65. [PMID: 16805846 DOI: 10.1111/j.1471-4159.2006.03899.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Several studies have demonstrated that glucose deprivation, combined either with anoxia or with the inhibition of oxidative phosphorylation, leads to the development of ischemic tolerance in neurons. The aim of our experiments was to investigate whether similar effects could be achieved by transient energy deprivation without either anoxia or the inhibition of the electron transfer chain. Preconditioning was carried out by incubating primary rat cortical neuronal cultures for 3, 6 or 9 h in a glucose- and amino acid-free balanced salt solution supplemented with B27 in normoxic conditions. After 24 h, neuronal cultures were exposed to oxygen-glucose deprivation, glutamate or hydrogen peroxide. Cell viability was measured 24 h after the lethal insults. Potential mechanisms that can influence free radical production were also examined. Energy deprivation protected neuronal cells against lethal stimuli (e.g. cell survival after oxygen-glucose deprivation was 33.1 +/- 0.52% in the untreated group and 80.1 +/- 1.27% in the 9-h energy deprivation group), reduced mitochondrial membrane potential, decreased free radical formation, attenuated the intracellular free calcium surge upon glutamate receptor stimulation, and resulted in an elevated level of GSH. Our findings show that transient energy deprivation induces delayed preconditioning and prevents oxidative injuries and neuronal cell death.
Collapse
Affiliation(s)
- Tamás Gáspár
- Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina 27157-1010, USA.
| | | | | | | | | | | | | |
Collapse
|
84
|
Zhang A, Lorke DE, Wu SX, Yew DT. Caspase-3 immunoreactivity in different cortical areas of young and aging macaque (Macaca mulatta) monkeys. Neurosignals 2006; 15:64-73. [PMID: 16847399 DOI: 10.1159/000094602] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 06/06/2006] [Indexed: 12/26/2022] Open
Abstract
It has been shown that cytochrome-c-dependent caspase-3 activation is significantly elevated in the aging macaque brain. To assess the underlying age-related changes in the cellular distribution of caspase-3, we have examined the motor cortex, cerebellum and hippocampus of young (4-year-old, n = 4) and old (20-year-old, n = 4)rhesus monkeys by immunohistochemistry. Western blot analyses of brain homogenate showed that the antibody reacted only with inactive 32-kDa procaspase and its active 20- and 17-kDa subunits, formed after granzyme B exposure. In the motor cortex, pyramidal cells of layers III and V were moderately labeled; the underlying white matter contained weakly stained astrocytes. In the hippocampus, hilar neurons and pyramidal cells in CA3 showed the strongest immunoreaction, pyramidal cells in CA1 and granule cells of the dentate gyrus were also strongly labeled. In contrast, CA2 pyramidal cells were only weakly stained, and neurons of the molecular layer were unlabeled. Weak caspase-3 immunoreaction of CA2 neurons parallels known decreased susceptibility to apoptosis. In the cerebellar cortex, clusters of strongly labeled Purkinje cells were observed next to groups of weakly and unstained cells; granule cells were generally unstained. The brains of aging monkeys displayed a similar pattern of caspase-3 immunoreactivity. In neocortical layer V, however, scattered very strongly labeled pyramidal cells were regularly detected, which were not observed in younger animals. This clustering of caspase-3 indicates increased vulnerability of a subset of pyramidal cells in the aging brain.
Collapse
Affiliation(s)
- Aiqun Zhang
- Department of Anatomy, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | | | | | | |
Collapse
|
85
|
Abstract
Brain cells are highly energy dependent for maintaining ion homeostasis during high metabolic activity. During active periods, full mitochondrial function is essential to generate ATP from electrons that originate with the oxidation of NADH. Decreasing brain metabolism is a significant cause of cognitive abnormalities of Alzheimer disease (AD), but it remains uncertain whether this is the cause of further pathology or whether synaptic loss results in a lower energy demand. Synapses are the first to show pathological symptoms in AD before the onset of clinical symptoms. Because synaptic function has high energy demands, interruption in mitochondrial energy supply could be the major factor in synaptic failure in AD. A newly discovered age-related decline in neuronal NADH and redox ratio may jeopardize this function. Mitochondrial dehydrogenases and several mutations affecting energy transfer are frequently altered in aging and AD. Thus, with the accumulation of genetic defects in mitochondria at the level of energy transfer, the issue of neuronal susceptibility to damage as a function of age and age-related disease becomes important. In an aging rat neuron model, mitochondria are both chronically depolarized and produce more reactive oxygen species with age. These concepts suggest that multiple treatment targets may be needed to reverse this multifactorial disease. This review summarizes new insights based on the interaction of mitoenergetic failure, glutamate excitotoxicity, and amyloid toxicity in the exacerbation of AD.
Collapse
Affiliation(s)
- Mordhwaj S Parihar
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626, USA
| | | |
Collapse
|
86
|
Cui Y, Xu X, Bi H, Zhu Q, Wu J, Xia X, Ho PCP. Expression modification of uncoupling proteins and MnSOD in retinal endothelial cells and pericytes induced by high glucose: the role of reactive oxygen species in diabetic retinopathy. Exp Eye Res 2006; 83:807-16. [PMID: 16750827 DOI: 10.1016/j.exer.2006.03.024] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Accepted: 03/31/2006] [Indexed: 11/17/2022]
Abstract
Uncoupling proteins (UCPs) are mitochondrial transporters present in the inner membrane of mitochondria. They belong to the family of anion mitochondrial carriers. UCPs could act as proton carriers activated by metabolites and create a shunt between complexes of the respiratory chain and ATP synthase. The increased leakiness of the mitochondrial inner membrane to protons may be to minimize superoxide production by limiting the maximum Deltamu(H+). The purpose of this study was to detect UCP expression in retinal capillary cells and their modification in high levels of glucose. The role of reactive oxygen species (ROS) of mitochondria and UCPs in pathogenesis of diabetic retinopathy was investigated. Bovine retinal capillary endothelial cells and pericytes were cultured with selective culture media, respectively. Passage cells were cultured in three different glucose concentrations (5, 23, 30 mM) until passage four. ROS changes in mitochondria of these cells in different glucose concentrations were detected with scanning laser confocal microscopy (SLCM). The mitochondria membrane potential (Deltapsi), cell death rate and apoptosis rate were measured with flowing cytometry. UCP expression in retinal capillary cells was detected by immunocytochemistry. Expression and modification of MnSOD and uncoupling proteins (UCPs) in different concentrations of glucose were detected by means of semi-quantitative RT-PCR. ROS in mitochondria of both endothelial cells and pericytes increased as the glucose concentration of media increased. Deltapsi and cell death rate of endothelial cells increased also. ROS was correlated to Deltapsi and cell death rate positively in endothelial cells. No difference in Deltapsi and cell death rate among different glucose levels was found in pericytes. Apoptosis rate of endothelial cells and pericytes in high glucose levels was higher than that in lower glucose levels. UCP1 and UCP2 were expressed in cultured retinal capillary cells whereas UCP3 was not. At high levels of glucose, expression of UCP1, UCP2 and MnSOD increased to accommodate ROS production compensatively. The compensative mechanism disappeared when glucose concentration was too high (30 mM). The results of this study showed that increasing mitochondrial ROS could be induced by high glucose concentration. Those proteins related to antioxidation mechanism, such as MnSOD and UCPs, could exert compensative action to a certain extent. This compensative action was insufficient when the glucose concentration was too high.
Collapse
Affiliation(s)
- Yan Cui
- Department of Ophthalmology, Shanghai First People's Hospital, 85 Wu Jin Road, Shanghai 200080, PR China
| | | | | | | | | | | | | |
Collapse
|
87
|
Szewczyk A, Skalska J, Głab M, Kulawiak B, Malińska D, Koszela-Piotrowska I, Kunz WS. Mitochondrial potassium channels: from pharmacology to function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:715-20. [PMID: 16787636 DOI: 10.1016/j.bbabio.2006.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 04/19/2006] [Accepted: 05/02/2006] [Indexed: 11/20/2022]
Abstract
Mitochondrial potassium channels, such as ATP-regulated or large conductance Ca2+ -activated and voltage gated channels were implicated in cytoprotective phenomenon in different tissues. Basic effects of these channels activity include changes in mitochondrial matrix volume, mitochondrial respiration and membrane potential, and generation of reactive oxygen species. In this paper, we describe the pharmacological properties of mitochondrial potassium channels and their modulation by channel inhibitors and potassium channel openers. We also discuss potential side effects of these substances.
Collapse
Affiliation(s)
- Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur st., 02-093 Warsaw, Poland.
| | | | | | | | | | | | | |
Collapse
|
88
|
Zhang M, Wang B, Ni YH, Liu F, Fei L, Pan XQ, Guo M, Chen RH, Guo XR. Overexpression of uncoupling protein 4 promotes proliferation and inhibits apoptosis and differentiation of preadipocytes. Life Sci 2006; 79:1428-35. [PMID: 16716360 DOI: 10.1016/j.lfs.2006.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2006] [Revised: 04/12/2006] [Accepted: 04/13/2006] [Indexed: 11/27/2022]
Abstract
Uncoupling proteins are a family of mitochondrial proteins involved in energy metabolism. We previously showed that uncoupling protein 4 (UCP4) is differentially expressed in omental adipose tissue in diet-induced obese and normal rats. However, the effect of UCP4 on adipocytes is unclear. In this work, we established a stable preadipocyte cell line overexpressing UCP4 to observe the direct effect of UCP4 on adipocytes. Cells overexpressing UCP4 showed significantly attenuated differentiation of preadipocytes into adipocytes. During differentiation, expression of adipogenesis-associated markers such as fatty acid synthetase, peroxisome proliferator-activated receptor gamma, CCAAT enhancer binding protein alpha, adipocyte lipid binding protein and lipoprotein lipase were downregulated. Preadipoctes expressing UCP4 grew faster and more of them stayed in S phase compared to control cells. In addition, UCP4 overexpression protected preadipocytes from apoptosis induced by serum deprivation. Our results demonstrate that overexpression of UCP4 can promote proliferation and inhibit apoptosis and differentiation of preadipocytes.
Collapse
Affiliation(s)
- Min Zhang
- Department of Pediatrics, Nanjing Maternity and Child Health Hospital of Nanjing Medical University, 210004 Nanjing, China
| | | | | | | | | | | | | | | | | |
Collapse
|
89
|
Abstract
Ischaemic preconditioning (IPC), also known as ischaemic tolerance (IT), is a phenomenon whereby tissue is exposed to a brief, sublethal period of ischaemia, which activates endogenous protective mechanisms, thereby reducing cellular injury that may be caused by subsequent lethal ischaemic events. The first description of this phenomenon was in the heart, which was reported by Murry and co-workers in 1986. Subsequent studies demonstrated IPC in lung, kidney and liver tissue, whereas more recent studies have concentrated on the brain. The cellular mechanisms underlying the beneficial effects of IPC remain largely unknown. This phenomenon, which has been demonstrated by using various injury paradigms in both cultured neurons and animal brain tissue, may be utilised to identify and characterise therapeutic targets for small-molecule, antibody, or protein intervention. This review will examine the experimental evidence demonstrating the phenomenon termed IPC in models of cerebral ischaemia, the cellular mechanisms that may be involved and the therapeutic implications of these findings.
Collapse
Affiliation(s)
- Kevin Pong
- Wyeth Research, Department of Neuroscience, Princeton, NJ 08543, USA.
| |
Collapse
|
90
|
Rudofsky G, Schroedter A, Schlotterer A, Voron'ko OE, Schlimme M, Tafel J, Isermann BH, Humpert PM, Morcos M, Bierhaus A, Nawroth PP, Hamann A. Functional polymorphisms of UCP2 and UCP3 are associated with a reduced prevalence of diabetic neuropathy in patients with type 1 diabetes. Diabetes Care 2006; 29:89-94. [PMID: 16373902 DOI: 10.2337/diacare.29.01.06.dc05-0757] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE We studied the association between polymorphisms in the UCP genes and diabetes complications in patients with type 1 diabetes. RESEARCH DESIGN AND METHODS We analyzed 227 patients with type 1 diabetes using PCR and subsequent cleavage by restriction endonucleases for the promoter variants A-3826G in the UCP1 gene, G-866A in the UCP2 gene, and C-55T in the UCP3 gene. RESULTS No effect of the A-3826G polymorphism in the UCP1 gene on diabetes complications was found. Patients who were heterozygous or homozygous for the G-866A polymorphism in the UCP2 gene or the C-55T polymorphism in the UCP3 gene had a significantly reduced prevalence of diabetic neuropathy (UCP2: odds ratio 0.44 [95% CI 0.24-0.79], P = 0.007; UCP3: 0.48 [0.25-0.92], P = 0.031), whereas there was no association with other diabetes complications. This effect was stronger when G-866A and C-55T occurred in a cosegregatory manner (UCP2 and UCP3: 0.28 [0.12-0.65], P = 0.002). Furthermore, a multiple logistic regression model showed an age- and diabetes duration-independent effect of the cosegregated polymorphisms on the prevalence of diabetic neuropathy (P = 0.013). CONCLUSIONS Our data indicate that both the G-866A polymorphism in the UCP2 gene and the C-55T polymorphism in the UCP3 gene are associated with a reduced risk of diabetic neuropathy in type 1 diabetes. Thus, the results presented here support the hypothesis that higher expression of uncoupling protein might prevent mitochondria-mediated neuronal injury and, ultimately, diabetic neuropathy.
Collapse
Affiliation(s)
- Gottfried Rudofsky
- Division of Endocrinology and Metabolism, Department of Medicine, University of Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
91
|
Andrews ZB, Diano S, Horvath TL. Mitochondrial uncoupling proteins in the CNS: in support of function and survival. Nat Rev Neurosci 2005; 6:829-40. [PMID: 16224498 DOI: 10.1038/nrn1767] [Citation(s) in RCA: 278] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mitochondrial uncoupling mediated by uncoupling protein 1 (UCP1) is classically associated with non-shivering thermogenesis by brown fat. Recent evidence indicates that UCP family proteins are also present in selected neurons. Unlike UCP1, these proteins (UCP2, UCP4 and BMCP1/UCP5) are not constitutive uncouplers and are not crucial for non-shivering thermogenesis. However, they can be activated by free radicals and free fatty acids, and their activity has a profound influence on neuronal function. By regulating mitochondrial biogenesis, calcium flux, free radical production and local temperature, neuronal UCPs can directly influence neurotransmission, synaptic plasticity and neurodegenerative processes. Insights into the regulation and function of these proteins offer unsuspected avenues for a better understanding of synaptic transmission and neurodegeneration.
Collapse
Affiliation(s)
- Zane B Andrews
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, FMB 339, New Haven, Connecticut 06510, USA
| | | | | |
Collapse
|
92
|
Schmidt RE, Dorsey DA, Parvin CA, Beaudet LN. Sympathetic neuroaxonal dystrophy in the aged rat pineal gland. Neurobiol Aging 2005; 27:1514-23. [PMID: 16202480 DOI: 10.1016/j.neurobiolaging.2005.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 07/26/2005] [Accepted: 08/05/2005] [Indexed: 11/24/2022]
Abstract
Dysfunction of circadian melatonin production by the pineal gland in aged humans and rats is thought to reflect the functional loss of its sympathetic innervation. Our ultrastructural neuropathologic studies of the sympathetic innervation of the pineal gland of aged (24 months old) Fischer-344 and Sprague-Dawley rats showed loss of nerve terminals as well as the development of neuroaxonal dystrophy (NAD), an ultrastructurally distinctive distal axonopathy, far in excess of that in young control rats. Immunolocalization of tyrosine hydroxylase confirmed the age-related loss of normal noradrenergic innervation and development of NAD. NAD was more frequent in aged female rats compared to males and was particularly severe in aged female Sprague-Dawley rats compared to Fischer-344 rats. Pineal NGF content was significantly increased or unchanged in female and male aged Fischer-344 rats, respectively, compared to young controls. The rat pineal is a sensitive experimental model for the quantitative ultrastructural examination of age-related neuropathological changes in nerve terminals of postganglionic noradrenergic sympathetic axons, changes which may reflect similar changes in the diffusely distributed sympathetic innervation of other targeted endorgans.
Collapse
Affiliation(s)
- Robert E Schmidt
- Department of Pathology and Immunology, Division of Neuropathology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8118, Saint Louis, MO 63110, USA.
| | | | | | | |
Collapse
|
93
|
Trimmer PA, Borland MK. Differentiated Alzheimer's disease transmitochondrial cybrid cell lines exhibit reduced organelle movement. Antioxid Redox Signal 2005; 7:1101-9. [PMID: 16115014 DOI: 10.1089/ars.2005.7.1101] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The axonal transport and function of organelles like mitochondria and lysosomes may be impaired and play an important role in the pathogenesis of Alzheimer's disease (AD). Unique cybrid cell lines that model AD pathology were created by fusing platelets containing mitochondria from age-matched AD and control volunteers with mitochondrial DNA-free SH-SY5Y human neuroblastoma cells. These cybrid lines were differentiated to form process-bearing neuronal cells. Mitochondria and lysosomes in the neurites of each cybrid line were fluorescently labeled to determine the kinetics of organelle movement. The mitochondria in AD cybrid neurites were elongate, whereas the mitochondria in control cybrid neurites were short and more punctate. The mean velocity of mitochondrial movement, as well as the percentage of moving mitochondria, was significantly reduced in AD cybrids. The velocity of lysosomal movement was also reduced in the processes of AD cybrid cells, suggesting that the axonal transport machinery may be compromised in cybrid cell lines that contain mitochondrial DNA derived from AD patients. Reduced mitochondrial and lysosomal movement in susceptible neurons may compromise function in metabolically demanding structures like synaptic terminals and participate in the terminal degeneration that is characteristic of AD.
Collapse
Affiliation(s)
- Patricia A Trimmer
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA.
| | | |
Collapse
|
94
|
Yang Y, Liu X, Long Y, Wang F, Ding JH, Liu SY, Sun YH, Yao HH, Wang H, Wu J, Hu G. Systematic administration of iptakalim, an ATP-sensitive potassium channel opener, prevents rotenone-induced motor and neurochemical alterations in rats. J Neurosci Res 2005; 80:442-9. [PMID: 15795934 DOI: 10.1002/jnr.20467] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Our previous studies revealed that iptakalim, a novel ATP-sensitive potassium channel opener, has a significant neuroprotective function against ischemia in vivo or rotenone-induced neurotoxicity in vitro. To investigate the potential pharmaceutical benefit of ATP-sensitive potassium channel openers on neurodegenerative diseases, we studied the effects of iptakalim and diazoxide, a selective mitochondrial ATP-sensitive potassium channel opener, on the rotenone-induced nigrostriatal degeneration in rats. Iptakalim (1.5 mg/kg/day, orally) or diazoxide (1.5 mg/kg/day, orally) alone was administered to rats for 3 days, and then for 4 weeks was used daily with an injection of rotenone (2.5 mg/kg/day, subcutaneously) 1 hr later each time. The results showed that rotenone-infused rats exhibited parkinsonian symptoms and had dopamine depletion in the striatum and substantia nigra. Pretreatment with iptakalim or diazoxide prevented rotenone-induced catalepsy and the reduction of striatum dopamine contents. Moreover, iptakalim and diazoxide reduced the enzymatic activities and mRNA levels of inducible nitric oxide synthase elicited by chronic administration of rotenone. These neuroprotective effects of iptakalim and diazoxide were abolished by 5-hydroxydecanoate, a selective mitochondrial ATP-sensitive potassium channel blocker. In conclusion, our data suggested that mitochondrial ATP-sensitive potassium channels might play a key role in preventing both parkinsonian symptoms and neurochemistry alterations induced by rotenone in rats. The selective activation of mitochondrial ATP-sensitive potassium channels may provide a new therapeutic strategy for prevention and treatment of neurodegenerative disorders such as Parkinson's disease.
Collapse
Affiliation(s)
- Yong Yang
- Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu, PR China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
95
|
HIV-1 transactivator of transcription protein induces mitochondrial hyperpolarization and synaptic stress leading to apoptosis. THE JOURNAL OF IMMUNOLOGY 2005; 174:4333-44. [PMID: 15778398 DOI: 10.4049/jimmunol.174.7.4333] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Despite the efficacy of highly active antiretroviral therapy in reducing viral burden, neurologic disease associated with HIV-1 infection of the CNS has not decreased in prevalence. HIV-1 does not induce disease by direct infection of neurons, although extensive data suggest that intra-CNS viral burden correlates with both the severity of virally induced neurologic disease, and with the generation of neurotoxic metabolites. Many of these molecules are capable of inducing neuronal apoptosis in vitro, but neuronal apoptosis in vivo does not correlate with CNS dysfunction, thus prompting us to investigate cellular and synaptic events occurring before cell death that may contribute to HIV-1-associated neurologic disease. We now report that the HIV-1 regulatory protein transactivator of transcription protein (Tat) increased oxidative stress, ATP levels, and mitochondrial membrane potential in primary rodent cortical neurons. Additionally, a proinflammatory cellular metabolite up-regulated by Tat, platelet-activating factor, also induced oxidative stress and mitochondrial hyperpolarization in neurons, suggesting that this type of metabolic dysfunction may occur on a chronic basis during HIV-1 infection of the CNS. Tat-induced mitochondrial hyperpolarization could be blocked with a low dose of the protonophore FCCP, or the mitochondrial KATP channel antagonist, tolbutamide. Importantly, blocking the mitochondrial hyperpolarization attenuated Tat-induced neuronal apoptosis, suggesting that increased mitochondrial membrane potential may be a causal event in precipitating neuronal apoptosis in cell culture. Finally, Tat and platelet-activating factor also increased neuronal vesicular release, which may be related to increased mitochondrial bioenergetics and serve as a biomarker for early damage to neurons.
Collapse
|
96
|
Bednarczyk P, Dołowy K, Szewczyk A. Matrix Mg2+ regulates mitochondrial ATP-dependent potassium channel from heart. FEBS Lett 2005; 579:1625-32. [PMID: 15757652 DOI: 10.1016/j.febslet.2005.01.077] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 01/11/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
Mitochondrial ATP-regulated potassium (mitoKATP) channels play an important role in cardioprotection. Single channel activity was measured after reconstitution of inner mitochondrial membranes from bovine myocardium into a planar lipid bilayer. After incorporation, the potassium channel was recorded with a mean conductance of 103+/-9 pS. The channel activity was inhibited by ATP/Mg and activated by GDP. Magnesium ions alone affected, in a dose dependent manner, both the channel conductance and the open probability. Magnesium ions regulated the mitoKATP channel only when added to the trans compartment. We conclude that Mg2+ regulates the cardiac mitoKATP channel from the matrix site by affecting both the channel conductance and gating.
Collapse
Affiliation(s)
- Piotr Bednarczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | | | | |
Collapse
|
97
|
Li L, Prabhakaran K, Mills EM, Borowitz JL, Isom GE. Enhancement of Cyanide-Induced Mitochondrial Dysfunction and Cortical Cell Necrosis by Uncoupling Protein-2. Toxicol Sci 2005; 86:116-24. [PMID: 15800031 DOI: 10.1093/toxsci/kfi164] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Uncoupling protein 2 (UCP-2) is expressed in the inner mitochondrial membrane and modulates mitochondrial function by partially uncoupling oxidative phosphorylation, and it has been reported to modulate cell death. Cyanide is a potent neurotoxin that inhibits complex IV to alter mitochondrial function to induce neuronal death. In primary rat cortical cells KCN produced an apoptotic death at 200-400 microM. Higher concentrations of potassium cyanide (KCN) (500-600 microM) switched the mode of death from apoptosis to necrosis. In necrotic cells, ATP levels were severely depleted as compared to cortical cells undergoing apoptosis. To determine if UCP-2 expression could alter KCN-induced cell death, cells were transiently transfected with full-length human UCP-2 cDNA (UCP-2+). Overexpression switched the mode of death produced by KCN (400 microM) from apoptosis to necrosis. The change in cell death was mediated by impaired mitochondrial function as reflected by a marked decrease of ATP levels and reduction in mitochondrial membrane potential. RNA interference or transfection with a dominant interfering mutant blocked the necrotic response observed in UCP-2+ cells. Additionally, treatment of UCP-2+ cells with cyclosporin A blocked necrosis, indicating the involvement of mitochondrial permeability pore transition in the necrotic death. These results show that increased expression of UCP-2 alters the response to a potent mitochondrial toxin by switching the mode of cell death from apoptosis to necrosis. It is concluded that UCP-2 levels influence cellular responses to cyanide-induced mitochondrial dysfunction.
Collapse
Affiliation(s)
- L Li
- Department of Medicinal Chemistry & Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907-1333, USA
| | | | | | | | | |
Collapse
|
98
|
Sokolova IM, Sokolov EP. Evolution of mitochondrial uncoupling proteins: novel invertebrate UCP homologues suggest early evolutionary divergence of the UCP family. FEBS Lett 2005; 579:313-7. [PMID: 15642337 DOI: 10.1016/j.febslet.2004.11.103] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 11/10/2004] [Accepted: 11/15/2004] [Indexed: 11/16/2022]
Abstract
Current hypothesis about the evolution of uncoupling proteins (UCPs) proposed by suggests that UCP4 is the earliest form of UCP ancestral to all other UCP orthologues. However, this hypothesis is difficult to reconcile with a narrow tissue distribution of UCP4 (which is a brain-specific isoform), suggesting highly specialized rather than anfcestral function for this protein. We searched for UCP2, UCP3, and UCP5 homologues in invertebrate genomes using amplification with degenerate primers designed against UCP2-specific conserved sequences and/or BLASTP search with stringent ad hoc criteria to distinguish between homologues and orthologues of different UCPs. Our study identified invertebrate UCP homologues similar to UCP2 and 3 (which we termed UCP6) and an invertebrate homologue of UCP5. Phylogenetic analysis indicates that there are at least three clades of UCPs in invertebrates, which are closely related to vertebrate UCP1-3, UCP4, and UCP5, respectively, and shows early evolutionary divergence of UCPs, which pre-dates the divergence of protostomes and deuterostomes. It also suggests that the newly identified UCP6 proteins from invertebrates are ancestral to the vertebrate UCP1, UCP2, and UCP3, and that divergence of these three vertebrate orthologues occurred late in evolution of the vertebrates. This study refutes the hypothesis of Hanak and Jezek (2001) that UCP4 is an ancestral form for all UCPs, and shows early evolutionary diversification of this protein family, which corresponds to their proposed functional diversity in regulation of proton leak, antioxidant defense and apoptosis.
Collapse
Affiliation(s)
- I M Sokolova
- Biology Department, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, USA.
| | | |
Collapse
|
99
|
Matarrese P, Tinari A, Mormone E, Bianco GA, Toscano MA, Ascione B, Rabinovich GA, Malorni W. Galectin-1 Sensitizes Resting Human T Lymphocytes to Fas (CD95)-mediated Cell Death via Mitochondrial Hyperpolarization, Budding, and Fission. J Biol Chem 2005; 280:6969-85. [PMID: 15556941 DOI: 10.1074/jbc.m409752200] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Galectins have emerged as a novel family of immunoregulatory proteins implicated in T cell homeostasis. Recent studies showed that galectin-1 (Gal-1) plays a key role in tumor-immune escape by killing antitumor effector T cells. Here we found that Gal-1 sensitizes human resting T cells to Fas (CD95)/caspase-8-mediated cell death. Furthermore, this protein triggers an apoptotic program involving an increase of mitochondrial membrane potential and participation of the ceramide pathway. In addition, Gal-1 induces mitochondrial coalescence, budding, and fission accompanied by an increase and/or redistribution of fission-associated molecules h-Fis and DRP-1. Importantly, these changes are detected in both resting and activated human T cells, suggesting that Gal-1-induced cell death might become an excellent model to analyze the morphogenetic changes of mitochondria during the execution of cell death. This is the first association among Gal-1, Fas/Fas ligand-mediated cell death, and the mitochondrial pathway, providing a rational basis for the immunoregulatory properties of Gal-1 in experimental models of chronic inflammation and cancer.
Collapse
Affiliation(s)
- Paola Matarrese
- Department of Drug Research and Evaluation, and Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, Rome 00161, Italy
| | | | | | | | | | | | | | | |
Collapse
|
100
|
Porter MY, Turmaine M, Mole SE. Identification and characterization ofCaenorhabditis elegans palmitoyl protein thioesterase1. J Neurosci Res 2005; 79:836-48. [PMID: 15672447 DOI: 10.1002/jnr.20403] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Infantile neuronal ceroid lipofuscinosis (INCL; Batten disease) is a severe neurodegenerative disorder of childhood characterized by the accumulation of autofluorescent storage material in lysosomes. It is caused by mutation of the CLN1/PPT1 gene, which encodes the lysosomal enzyme palmitoyl protein thioesterase-1 (PPT1), but the mechanism of disease pathogenesis and substrates for the enzyme are unknown. Caenorhabditis elegans is a simple nematode worm, with a fully sequenced genome, which is easy to maintain and manipulate. It has a completely mapped cell lineage and nervous system and has already provided clues about the pathogenesis of several human neuronal and lysosomal storage disorders. We have identified and characterized a PPT1 homologue in C. elegans. We found that, although this gene was not essential for the animal's survival, its mutation resulted in a mild developmental and reproductive phenotype, affected the number and size of mitochondria, and resulted in an abnormality in mitochondrial morphology, possibly suggestive of a role for this organelle in INCL pathogenesis. This strain, deleted for ppt-1, potentially provides a model system for the study of PPT1 and the pathogenesis of INCL.
Collapse
Affiliation(s)
- Morwenna Y Porter
- Department of Paediatrics and Child Health, Royal Free and University College Medical School, University College London, London, United Kingdom
| | | | | |
Collapse
|