Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are closely linked to degenerative diseases such as Alzheimer's disease, Parkinson's, neuronal death including ischemic and hemorrhagic stroke, acute and chronic degenerative cardiac myocyte death, and cancer. As a byproduct of oxidative phosphorylation, a steady stream of reactive species emerge from our cellular energy plants, the mitochondria. ROS and RNS potentially cause damage to all cellular components. Structure alteration, biomolecule fragmentation, and oxidation of side chains are trade-offs of cellular energy production. ROS and RNS escape results in the activation of cytosolic stress pathways, DNA damage, and the upregulation of JNK, p38, and p53. Incomplete scavenging of ROS and RNS particularly affects the mitochondrial lipid cardiolipin (CL), triggers the release of mitochondrial cytochrome c, and activates the intrinsic death pathway. Due to the active redox environment and the excess of NADH and ATP at the inner mitochondrial membrane, a broad range of agents including electron acceptors, electron donors, and hydride acceptors can be used to influence the biochemical pathways. The key to therapeutic value is to enrich selective redox modulators at the target sites. Our approach is based on conjugating nitroxides to segments of natural products with relatively high affinity for mitochondrial membranes. For example, a modified gramicidin S segment was successfully used for this purpose and proven to be effective in preventing superoxide production in cells and CL oxidation in mitochondria and in protecting cells against a range of pro-apoptotic triggers such as actinomycin D, radiation, and staurosporine. More importantly, these mitochondria-targeted nitroxide/gramicidin conjugates were able to protect against apoptosis in vivo by preventing CL oxidation induced by intestinal hemorrhagic shock. Optimization of nitroxide carriers could lead to a new generation of effective antiapoptotic agents acting at an early mitochondrial stage. Alternative chemistry-based approaches to targeting mitochondria include the use of proteins and peptides, as well as the attachment of payloads to lipophilic cationic compounds, sulfonylureas, anthracyclines, and other agents with proven or hypothetical affinities for mitochondria. Manganese superoxide dismutase (MnSOD), SS tetrapeptides with 2',6'-dimethyltyrosine (Dmt) residues, rhodamine, triphenylphosphonium salts, nonopioid analgesics, adriamycin, and diverse electron-rich aromatics and stilbenes were used to influence mitochondrial biochemistry and the biology of aging. Some general structural principles for effective therapeutic agents are now emerging. Among these are the presence of basic or positively charged functional groups, hydrophobic substructures, and, most promising for future selective strategies, classes of compounds that are actively shuttled into mitochondria, bind to mitochondria-specific proteins, or show preferential affinity to mitochondria-specific lipids.
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PMID:Targeting mitochondria. 1819 22

Antioxidants specifically addressed to mitochondria have been studied for their ability to decelerate aging of organisms. For this purpose, a project has been established with participation of several research groups from Belozersky Institute of Physico-Chemical Biology and some other Russian research institutes as well as two groups from the USA and Sweden, with support by the "Mitotechnology" company founded by "RAInKo" company (O. V. Deripaska and Moscow State University). This paper summarizes the first results of the project and estimates its prospects. Within the framework of the project, antioxidants of a new type (SkQ) were synthesized comprising plastoquinone (an antioxidant moiety), a penetrating cation, and decane or pentane linker. Using planar bilayer phospholipid membranes, we selected SkQ derivatives with the highest penetrating ability, namely plastoquinonyl-decyl-triphenylphosphonium (SkQ1), plastoquinonyl-decyl-rhodamine 19 (SkQR1), and methylplastoquinonyl-decyl-triphenylphosphonium (SkQ3). Anti- and prooxidant properties of these substances and also of ubiquinone and ubiquinonyl-decyl-triphenylphosphonium (MitoQ) were tested on isolated mitochondria. Micromolar concentrations of cationic quinones are found to be very strong prooxidants, but in lower (sub-micromolar) concentrations they display antioxidant activity. The antioxidant activity decreases in the series SkQ1=SkQR1>SkQ3>MitoQ, so the window between the anti- and prooxidant effects is smallest for MitoQ. SkQ1 is rapidly reduced by complexes I and II of the mitochondrial respiratory chain, i.e. it is a rechargeable antioxidant. Extremely low concentrations of SkQ1 and SkQR1 completely arrest the H2O2-induced apoptosis in human fibroblasts and HeLa cells (for SkQ1 C1/2=1.10(-9) M). Higher concentrations of SkQ are required to block necrosis initiated by reactive oxygen species (ROS). In mice, SkQ1 decelerates the development of three types of accelerated aging (progeria) and also of normal aging, and this effect is especially demonstrative at early stages of aging. The same pattern is shown in invertebrates (drosophila and daphnia). In mammals, the effect of SkQs on aging is accompanied by inhibition of development of such age-related diseases as osteoporosis, involution of thymus, cataract, retinopathy, etc. SkQ1 manifests a strong therapeutic action on some already developed retinopathies, in particular, congenital retinal dysplasia. With drops containing 250 nM SkQ1, vision is recovered in 50 of 66 animals who became blind because of retinopathy. SkQ1-containing drops instilled in the early stage of the disease prevent the loss of sight in rabbits with experimental uveitis and restore vision to animals that had already become blind. A favorable effect is also achieved in experimental glaucoma in rabbits. Moreover, the pretreatment of rats with 0.2 nmol SkQ1 per kg body weight significantly decreases the H2O2-induced arrhythmia of the isolated heart. SkQ1 strongly reduces the damaged area in myocardial infarction or stroke and prevents the death of animals from kidney infarction. In p53-/- mice, SkQ1 decreases the ROS level in the spleen cells and inhibits appearance of lymphomas which are the main cause of death of such animals. Thus, it seems reasonable to perform clinical testing of SkQ preparations as promising drugs for treatment of age-related and some other severe diseases of human and animals.
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PMID:A biochemical approach to the problem of aging: "megaproject" on membrane-penetrating ions. The first results and prospects. 1820 23

Despite its early discovery and high sequence homology to the other VEGF family members, the biological functions of VEGF-B remain poorly understood. We revealed here a novel function for VEGF-B as a potent inhibitor of apoptosis. Using gene expression profiling of mouse primary aortic smooth muscle cells, and confirming the results by real-time PCR using mouse and rat cell lines, we showed that VEGF-B inhibited the expression of genes encoding the proapoptotic BH3-only proteins and other apoptosis- and cell death-related proteins, including p53 and members of the caspase family, via activation of VEGFR-1. Consistent with this, VEGF-B treatment rescued neurons from apoptosis in the retina and brain in mouse models of ocular neurodegenerative disorders and stroke, respectively. Interestingly, VEGF-B treatment at the dose effective for neuronal survival did not cause retinal neovascularization, suggesting that VEGF-B is the first member of the VEGF family that has a potent antiapoptotic effect while lacking a general angiogenic activity. These findings indicate that VEGF-B may potentially offer a new therapeutic option for the treatment of neurodegenerative diseases.
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PMID:VEGF-B inhibits apoptosis via VEGFR-1-mediated suppression of the expression of BH3-only protein genes in mice and rats. 1825 7

The antioxidant activity of C.oil in cerebral stroke has been reported earlier. We have attempted here to clarify the mechanisms underlying the neuroprotection against experimental cerebral ischemia by Curcuma oil (C.oil), isolated from the rhizomes of Curcuma longa. C.oil (250 mg/kg i.p.) was given 30 min before focal ischemia in rats caused by occlusion of the middle cerebral artery (1h of occlusion, 24h of reflow). Ischemia, leads to elevation in [Ca(2+)] this sets into motion a cascades of ischemic injury which was attenuated by C.oil. C.oil reduced post-ischemic brain neutrophil infiltration in the ischemic area, controlled tissue NOx levels and the neuronal levels of nitric oxide, peroxynitrite and reactive oxygen species when measured after 24h of reflow. Double immunofluorescence staining analysis and Western immunoblot analysis with C.oil treatment showed that the expression of nitric oxide synthase (NOS) isoforms were decreased significantly compared to the untreated ischemia group. Ischemia is associated with increased in TUNEL (TdT-mediated dUTP nick-end labeling) positive cells in brain sections indicating DNA fragmentation. The C.oil treated group showed a significant decrease in numbers of apoptotic cells compared to the untreated ischemia group, as seen in the flowcytometric analysis of the neurons. Results of immunohistochemistry and Western immunoblot indicate that C.oil suppressed the elevated protein level of Bax, and aided mitochondrial translocation and activation of Bcl-2 by altered mitochondrial membrane potential. It also inhibits the cytosolic release of apoptogenic molecules like cytochrome c, inhibits the activation of caspase-3 and the expression of p53 ultimately inhibiting apoptosis. Our observations suggest that high levels of NO generated by NOS isoforms are partially responsible for exacerbating the neuronal damage induced by MCAo by intraluminal filament.
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PMID:Curcuma oil modulates the nitric oxide system response to cerebral ischemia/reperfusion injury. 1848 79

Apoptosis, or programmed cell death, is an essential process affecting homeostasis of cell growth, development, and the elimination of damaged or dangerous cells. Inappropriate cell death caused by oxidative stress has been implicated in the development of neurodegenerative diseases such as Alzheimer's, Parkinson's, and stroke. On the other hand, a defect in the cell death process leads to the development of cancer. For example, the main player of apoptosis, p53, is defective in many of the human cancers. Apoptosis is regulated by the interplay of pro-apoptotic and anti-apoptotic proteins from the Bcl-2 family and caspases. In particular, specific modulators of the activity of Caspase 3 could be very important for the development of therapies for diseases such as neurodegeneration and cancer. In this study, two V(H)Hs specific to Caspase 3 (VhhCasp31 and VhhCasp32) were isolated from a heavy chain antibody variable domain (V(H)H) phage display library and tested for their apoptosis-modulating effects. While VhhCasp31 was found to be antagonistic towards Caspase 3, VhhCasp32 was agonistic. Furthermore, when expressed as intrabodies in SHSY-5Y neuroblastoma cells, VhhCasp31 rendered cells resistant to oxidative-stress-induced apoptosis, whereas VhhCasp32 resulted in apoptosis. These V(H)H antagonist and agonist of apoptosis could have potential for the development of therapeutics for neurodegenerative diseases and cancer, respectively.
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PMID:Isolation and functional characterization of single domain antibody modulators of Caspase-3 and apoptosis. 1855 63

In the present study we tested the protective effects of netrin-1 in stroke and investigated the potential underlying mechanisms. When we performed middle cerebral artery occlusion (MCAO) on adult mice, up-regulation of the receptor uncoordinated gene 5H2 (UNC5H2) but not its ligand netrin-1 was detected with RT-PCR and immunohistochemistry. Injection of netrin-1, 1 day after MCAO, significantly reduced infarct volume at 3 days after MCAO as revealed by functional magnetic resonance imaging. The ischemic cortex was preserved when netrin-1 was continuously administered. Fluoro-Jade and terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling staining showed that netrin-1 reduced the number of dying neurons and apoptotic cells after MCAO. Ischemia-induced p53 expression was attenuated by netrin-1. We also tested the ability of netrin-1 to attract intrinsic neuronal stem cells to the infarct area. Both DCC and UNC5H2 were expressed in neurosphere culture and netrin-1 attracted stem cells in an in vitro transwell assay. However, in vivo netrin-1 administration did not enhance the MCAO-induced stem cell migration toward the infarct area. Our study shows that UNC5H2 expression was elevated after MCAO and administration of netrin-1 protected infarct tissue from p53-mediated apoptosis. These data indicate that the p53/dependent receptor pathway is involved in ischemic stroke pathology and suggest possible new stroke therapies.
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PMID:Netrin-1 attenuates ischemic stroke-induced apoptosis. 1878 16

Recovery from ischaemic stroke is dependent on survival of neurones, particularly in peri-infarcted regions. Angiogenesis is critical for the development of new microvessels resulting in the re-formation of collateral circulation associated with enhanced neuronal survival and reduced morbidity and mortality. Recently, the identification of a neurovascular niche has been described, where the co-ordinated effects of angiogenesis and migration of neuroprogenitor cells to damaged stroke regions were shown to be vital in the process of tissue remodelling. Cdk5, a serine/threonine kinase is highly expressed in the central nervous system, particularly following ischaemic stroke and its aberrant activation is directly associated with neuronal apoptosis and death. In contrast, recent evidence suggests that increased expression of Cdk5 by endothelium might be protective against cell death and/or promote angiogenesis leading to increased vessel formation and reperfusion. Owing to its known interaction with over 20 substrates including caspase-3, MEF2, Tau and p53, Cdk5 could be a master switch controlling both neuronal survival and revascularisation. Therefore its cell-specific pharmacological or genetic modulation using novel nanotechnology-based delivery systems could be of benefit when considering future stroke therapies.
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PMID:Cyclin-dependent kinase-5 targeting for ischaemic stroke. 1898 42

Antioxidants specifically addressed to mitochondria have been studied to determine if they can decelerate senescence of organisms. For this purpose, a project has been established with participation of several research groups from Russia and some other countries. This paper summarizes the first results of the project. A new type of compounds (SkQs) comprising plastoquinone (an antioxidant moiety), a penetrating cation, and a decane or pentane linker has been synthesized. Using planar bilayer phospholipid membrane (BLM), we selected SkQ derivatives with the highest permeability, namely plastoquinonyl-decyl-triphenylphosphonium (SkQ1), plastoquinonyl-decyl-rhodamine 19 (SkQR1), and methylplastoquinonyldecyltriphenylphosphonium (SkQ3). Anti- and prooxidant properties of these substances and also of ubiquinonyl-decyl-triphenylphosphonium (MitoQ) were tested in aqueous solution, detergent micelles, liposomes, BLM, isolated mitochondria, and cell cultures. In mitochondria, micromolar cationic quinone derivatives were found to be prooxidants, but at lower (sub-micromolar) concentrations they displayed antioxidant activity that decreases in the series SkQ1=SkQR1>SkQ3>MitoQ. SkQ1 was reduced by mitochondrial respiratory chain, i.e. it is a rechargeable antioxidant. Nanomolar SkQ1 specifically prevented oxidation of mitochondrial cardiolipin. In cell cultures, SkQR1, a fluorescent SkQ derivative, stained only one type of organelles, namely mitochondria. Extremely low concentrations of SkQ1 or SkQR1 arrested H(2)O(2)-induced apoptosis in human fibroblasts and HeLa cells. Higher concentrations of SkQ are required to block necrosis initiated by reactive oxygen species (ROS). In the fungus Podospora anserina, the crustacean Ceriodaphnia affinis, Drosophila, and mice, SkQ1 prolonged lifespan, being especially effective at early and middle stages of aging. In mammals, the effect of SkQs on aging was accompanied by inhibition of development of such age-related diseases and traits as cataract, retinopathy, glaucoma, balding, canities, osteoporosis, involution of the thymus, hypothermia, torpor, peroxidation of lipids and proteins, etc. SkQ1 manifested a strong therapeutic action on some already pronounced retinopathies, in particular, congenital retinal dysplasia. With drops containing 250 nM SkQ1, vision was restored to 67 of 89 animals (dogs, cats, and horses) that became blind because of a retinopathy. Instillation of SkQ1-containing drops prevented the loss of sight in rabbits with experimental uveitis and restored vision to animals that had already become blind. A favorable effect of the same drops was also achieved in experimental glaucoma in rabbits. Moreover, the SkQ1 pretreatment of rats significantly decreased the H(2)O(2) or ischemia-induced arrhythmia of the isolated heart. SkQs strongly reduced the damaged area in myocardial infarction or stroke and prevented the death of animals from kidney ischemia. In p53(-/-) mice, 5 nmol/kgxday SkQ1 decreased the ROS level in the spleen and inhibited appearance of lymphomas to the same degree as million-fold higher concentration of conventional antioxidant NAC. Thus, SkQs look promising as potential tools for treatment of senescence and age-related diseases.
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PMID:An attempt to prevent senescence: a mitochondrial approach. 1915 10

Hypoxia-inducible factor-1 (HIF-1) plays an essential role in cerebral ischemia as a proapoptotic factor. We hypothesized that HIF-1alpha siRNA can protect the brain from ischemic damage by inhibiting HIF-1alpha induced apoptotic pathway at the RNA level in a rat focal ischemic model. Results showed that treatment with HIF-1alpha siRNA reduced the infarct volume, decreased mortality, improved neurological deficits and reduced Evans blue extravasation. The expression of HIF-1alpha mRNA (Real-Time PCR) and protein were significantly silenced and the immunohistochemistry and Western blot revealed the suppression of HIF-1alpha, VEGF, p53 and Caspase-3. Double fluorescence labeling showed HIF-1alpha positive immunoreactive materials were partly colocalized with NeuN, p53 and Caspase-3 in the injured cerebral cortex. This study showed that HIF-1alpha siRNA may protect the ischemic-reperfused neurons in vivo via inhibition of HIF-1alpha, its downstream VEGF and other apoptotic-related proteins such as p53 and Caspase-3 and may have potentials for the early treatment of ischemic cerebral stroke.
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PMID:Early inhibition of HIF-1alpha with small interfering RNA reduces ischemic-reperfused brain injury in rats. 1916 37

The anticoagulant activated protein C (APC) protects neurons and endothelium via protease activated receptor (PAR)1, PAR3 and endothelial protein C receptor. APC is neuroprotective in stroke models. Bleeding complications may limit the pharmacologic utility of APC. Here, we compared the 3K3A-APC mutant with 80% reduced anticoagulant activity and wild-type (wt)-APC. Murine 3K3A-APC compared with wt-APC protected mouse cortical neurons from N-methyl-D-aspartate-induced apoptosis with twofold greater efficacy and more potently reduced N-methyl-D-aspartate excitotoxic lesions in vivo. Human 3K3A-APC protected human brain endothelial cells (BECs) from oxygen/glucose deprivation with 1.7-fold greater efficacy than wt-APC. 3K3A-APC neuronal protection required PAR1 and PAR3, as shown by using PAR-specific blocking antibodies and PAR1- and PAR3-deficient cells and mice. BEC protection required endothelial protein C receptor and PAR1. In neurons and BECs, 3K3A-APC blocked caspase-9 and -3 activation and induction of p53, and decreased the Bax/Bcl-2 pro-apoptotic ratio. After distal middle cerebral artery occlusion (dMCAO) in mice, murine 3K3A-APC compared with vehicle given 4:00 h after dMCAO improved the functional outcome and reduced the infarction volume by 50% within 3 days. 3K3A-APC compared with wt-APC multi-dosing therapy at 12:00 h, 1, 3, 5 and 7 days after dMCAO significantly improved functional recovery and reduced the infarction volume by 75% and 38%, respectively, within 7 days. The wt-APC, but not 3K3A-APC, significantly increased the risk of intracerebral bleeding as indicated by a 50% increase in hemoglobin levels in the ischemic hemisphere. Thus, 3K3A-APC offers a new approach for safer and more efficacious treatments of neurodegenerative disorders and stroke with APC.
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PMID:Neuroprotective activities of activated protein C mutant with reduced anticoagulant activity. 1930 48


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