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)

The major challenge in treating cancer is that many tumor cells carry mutations in key apoptotic genes such as p53, Bcl family proteins or those affecting caspase signaling. Such defects render treatment with traditional chemotherapeutic agents ineffective. Many studies have demonstrated the importance of caspase-independent cell death pathways in injury, degenerative diseases and tumor tissue. It is now recognized that in addition to their critical role in the production of cellular energy, mitochondria are also the source of key proapoptotic molecules involved in caspase activation. More recently, it has been discovered that in response to apoptotic stimuli, mitochondria can also release caspase-independent cell death effectors such as AIF and Endonuclease G. In this review, we examine the role of Bcl family proteins and poly(ADP-ribose) polymerase-1 signaling in the regulation of these apoptotic pathways and address the ongoing controversies in this field. Continued study of the mechanisms of apoptosis including caspase-independent death processes are likely to reveal novel therapeutic targets for the treatment of diverse human pathologies including cancer, neurodegenerative diseases and acute injuries such as stroke or myocardial infarction.
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PMID:Role of AIF in caspase-dependent and caspase-independent cell death. 1507 42

The p53 tumor suppressor gene is believed to play an important role in neuronal cell death in acute neurological disease and in neurodegeneration. The p53 signaling cascade is complex, and the mechanism by which p53 induces apoptosis is cell type-dependent. Using DNA microarray analysis, we have found a striking induction of the proapoptotic gene, SIVA. SIVA is a proapoptotic protein containing a death domain and interacts with members of the tumor necrosis factor receptor family as well as anti-apoptotic Bcl-2 family proteins. SIVA is induced following direct p53 gene delivery, treatment with a DNA-damaging agent camptothecin, and stroke injury in vivo. SIVA up-regulation is sufficient to initiate the apoptotic cascade in neurons. Through isolation and analysis of the SIVA promoter, we have identified response elements for both p53 and E2F1. Like p53, E2F1 is another tumor suppressor gene involved in the regulation of apoptosis, including neuronal injury models. We have identified E2F consensus sites in the promoter region, whereas p53 recognition sequences were found in intron1. Sequence analysis has shown that these consensus sites are also conserved between mouse and human SIVA genes. Electrophoretic mobility shift assays reveal that both transcription factors are capable of binding to putative consensus sites, and luciferase reporter assays reveal that E2F1 and p53 can activate transcription from the SIVA promoter. Here, we report that the proapoptotic gene, SIVA, which functions in a broad spectrum of cell types, is a direct transcriptional target for both tumor suppressors, p53 and E2F1.
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PMID:The proapoptotic gene SIVA is a direct transcriptional target for the tumor suppressors p53 and E2F1. 1510 21

No neuroprotective compounds are clinically available for the treatment of ischemic stroke. The potential salutary effect of pifithrin alpha, a novel-specific inhibitor of the transcription factor p53, administered 1-6 h following focal reversible cerebral ischemia, was investigated. Studies measuring histological, motor, and behavioral outcomes showed significant improvements in pifithrin alpha-treated animals. Pifithrin alpha reduced the number of apoptotic cells in the ischemic brain by inhibiting the binding of p53 to its DNA sites as it reduced the expression of the p53-related gene p21(WAF) without changing the amount of p53 protein itself.
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PMID:The role of p53-induced apoptosis in cerebral ischemia: effects of the p53 inhibitor pifithrin alpha. 1514 74

Cerebral cavernous malformations (CCM) consist of clusters of abnormally dilated blood vessels. Hemorrhaging of these lesions can cause seizures and lethal stroke. Three loci are associated with autosomal dominant CCM, and the causative genes have been identified for CCM1 and CCM2. We have generated mice with a targeted mutation of the Ccm1 gene, but an initial survey of 20 heterozygous mice failed to detect any cavernous malformations. To test the hypothesis that growth of cavernous malformations depends on somatic loss of heterozygosity at the Ccm1 locus, we bred animals that were heterozygous for the Ccm1 mutation and homozygous for loss of the tumor suppressor Trp53 (p53), which has been shown to increase the rate of somatic mutation. We observed vascular lesions in the brains of 55% of the double-mutant animals but none in littermates with other genotypes. Although the genetic evidence suggested somatic mutation of the wild-type Ccm1 allele, we were unable to demonstrate loss of heterozygosity by molecular methods. An alternative explanation is that p53 plays a direct role in formation of the vascular malformations. The striking similarity of the human and mouse lesions indicates that the Ccm1(+/-) Trp53(-/-) mice are an appropriate animal model of CCM.
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PMID:Loss of p53 sensitizes mice with a mutation in Ccm1 (KRIT1) to development of cerebral vascular malformations. 1550 22

The mood stabilizing drug lithium has emerged as a robust neuroprotective agent in preventing apoptosis of neurons. Long-term treatment with lithium effectively protects primary cultures of rat brain neurons from glutamate-induced, NMDA receptor-mediated excitotoxicity. This neuroprotection is accompanied by an inhibition of NMDA-receptor-mediated calcium influx, upregulation of anti-apoptotic Bcl-2, downregulation of pro-apoptotic p53 and Bax, and activation of cell survival factors. Lithium treatment antagonizes glutamate-induced activation of c-Jun-N-terminal kinase (JNK), p38 kinase, and AP-1 binding, which has a major role in cytotoxicity, and suppresses glutamate-induced loss of phosphorylated cAMP responsive element binding protein (CREB). Lithium also induces the expression of brain-derived neurotrophic factor (BDNF) and subsequent activation TrkB, the receptor for BDNF, in cortical neurons. The activation of BDNF/TrkB signaling is essential for the neuroprotective effects of this drug. In addition, lithium stimulates the proliferation of neuroblasts in primary cultures of CNS neurons. Lithium also shows neuroprotective effects in rodent models of diseases. In a rat model of stroke, post-insult treatment with lithium or valproate, another mood stabilizer, at therapeutic doses markedly reduces brain infarction and neurological deficits. This neuroprotection is associated with suppression of caspase-3 activation and induction of chaperone proteins such as heat shock protein 70. In a rat model of Huntington's disease (HD) in which an excitotoxin is unilaterally infused into the striatum, both long- and short-term pretreatment with lithium reduces DNA damage, caspase-3 activation, and loss of striatal neurons. This neuroprotection is associated with upregulation of Bcl-2. Lithium also induces cell proliferation near the injury site with a concomitant loss of proliferating cells in the subventricular zone. Some of these proliferating cells display neuronal or astroglial phenotypes. These results corroborate our findings obtained in primary neuronal cultures. The neuroprotective and neurotrophic actions of lithium have profound clinical implications. In addition to its present use in bipolar patients, lithium could be used to treat acute brain injuries such as stroke and chronic progressive neurodegenerative diseases.
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PMID:Neuroprotective and neurotrophic actions of the mood stabilizer lithium: can it be used to treat neurodegenerative diseases? 1558 3

We investigated the long-term effects of the thiazolidinedione PPARgamma activator pioglitazone on cardiac inflammation in stroke-prone spontaneously hypertensive rats (SHRSP), a model of malignant of hypertension. Six-week-old SHRSP were treated with pioglitazone (10 mg/kg per day p.o.) for 20 weeks. The rise in systolic blood pressure (SBP) in SHRSP was only transiently and slightly attenuated by pioglitazone (P < 0.05). On one hand, cardiac hypertrophy was little affected by the pioglitazone treatment, and there was only a reduction of subepicardial interstitial fibrosis. On the other hand, left ventricular NFkappaB and AP-1 binding activities, the expression of TNFalpha, and the adhesion of molecule PECAM were significantly decreased by pioglitazone treatment. Expression of the pro-apoptotic proteins p53 and bax was significantly increased by pioglitazone. Thus, pioglitazone-attenuated cardiac inflammation in SHRSP had little effect on BP or cardiac hypertrophy. PPARgamma activation may play a preventive cardiovascular role by offsetting the cardiac inflammatory response as demonstrated in this genetic model of malignant hypertension.
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PMID:Long-term effects of the PPAR gamma activator pioglitazone on cardiac inflammation in stroke-prone spontaneously hypertensive rats. 1564 37

Owing to improving preventative, diagnostic, and therapeutic measures for cardiovascular disease and a variety of cancers, the average ages of North Americans and Europeans continue to rise. Regrettably, accompanying this increase in life span, there has been an increase in the number of individuals afflicted with age-related neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, and stroke. Although different cell types and brain areas are vulnerable among these, each disorder likely develops from activation of a common final cascade of biochemical and cellular events that eventually lead to neuronal dysfunction and death. In this regard, different triggers, including oxidative damage to DNA, the overactivation of glutamate receptors, and disruption of cellular calcium homeostasis, albeit initiated by different genetic and/or environmental factors, can instigate a cascade of intracellular events that induce apoptosis. To forestall the neurodegenerative process, we have chosen specific targets to inhibit that are at pivotal rate-limiting steps within the pathological cascade. Such targets include TNF-alpha, p53, and GLP-1 receptor. The cytokine TNF-alpha is elevated in Alzheimer's disease, Parkinson's disease, stroke, and amyotrophic lateral sclerosis. Its synthesis can be reduced via posttranscriptional mechanisms with novel analogues of the classic drug, thalidomide. The intracellular protein and transcription factor, p53, is activated by the Alzheimer's disease toxic peptide, Abeta, as well as by excess glutamate and hypoxia to trigger neural cell death. It is inactivated by novel tetrahydrobenzothiazole and -oxazole analogues to rescue cells from lethal insults. Stimulation of the glucagon-like peptide-1 receptor (GLP-1R) in brain is associated with neurotrophic functions that, additionally, can protect cells against excess glutamate and other toxic insults.
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PMID:New therapeutic strategies and drug candidates for neurodegenerative diseases: p53 and TNF-alpha inhibitors, and GLP-1 receptor agonists. 1568 14

The tumor suppressor and transcription factor p53 is a key modulator of cellular stress responses, and activation of p53 can trigger apoptosis in many cell types including neurons. Apoptosis is a form of programmed cell death that occurs in neurons during development of the nervous system and may also be responsible for neuronal deaths that occur in neurological disorders such as stroke, and Alzheimer's and Parkinson's diseases. p53 production is rapidly increased in neurons in response to a range of insults including DNA damage, oxidative stress, metabolic compromise, and cellular calcium overload. Target genes induced by p53 in neurons include those encoding the pro-apoptotic proteins Bax and the BH3-only proteins PUMA and Noxa. In addition to such transcriptional control of the cell death machinery, p53 may more directly trigger apoptosis by acting at the level of mitochondria, a process that can occur in synapses (synaptic apoptosis). Preclinical data suggest that agents that inhibit p53 may be effective therapeutics for several neurodegenerative conditions.
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PMID:p53 in neuronal apoptosis. 1586 32

Poly(ADP-ribosyl) ation is a reversible post-translational protein modification implicated in the regulation of a number of biological functions. Whereas an 18 member superfamily of poly(ADP-ribose) polymerase (PARP) enzymes synthesize poly(ADP-ribose) (PAR), a single protein, PAR glycohydrolase (PARG) is responsible for the catabolism of the polymer. PARP-1 accounts for more than 90% of the poly(ADP-ribosyl)ating capacity of the cells. PARP-1 activated by DNA breaks cleaves NAD(+) into nicotinamide and ADP-ribose and uses the latter to synthesize long branching PAR polymers covalently attached to acceptor proteins including histones, DNA repair enzymes, transcription factors and PARP-1. Whereas activation of PARP-1 by mild genotoxic stimuli may facilitate DNA repair and cell survival, irreparable DNA damage triggers apoptotic or necrotic cell death. In apoptosis, early PARP activation may assist the apoptotic cascade [e.g. by stabilizing p53, by mediating the translocation of apoptosis inducing factor (AIF) from the mitochondria to the nucleus or by inhibiting early activation of DNases]. In most severe oxidative stress situations, excessive DNA damage causes over activation of PARP-1, which incapacitates the apoptotic machinery and switches the mode of cell death from apoptosis to necrosis. Besides serving as a cytotoxic mediator, PARP-1 is also involved in transcriptional regulation, most notably in the NF kappaB and AP-1 driven expression of inflammatory mediators. Pharmacological inhibition or genetic ablation of PARP-1 provided remarkable protection from tissue injury in various oxidative stress-related disease models ranging from stroke, diabetes, diabetic endothelial dysfunction, myocardial ischemia-reperfusion, shock, Parkinson's disease, arthritis, colitis to dermatitis and uveitis. These beneficial effects are attributed to inhibition of the PARP-1 mediated suicidal pathway and to reduced expression of inflammatory cytokines and other mediators (e.g. inducible nitric oxide synthase).
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PMID:Structure and function of poly(ADP-ribose) polymerase-1: role in oxidative stress-related pathologies. 1602 17

Pituitary apoplexy is an acute clinical event usually caused by hemorrhage or infarction in a pituitary adenoma. We report the unusual case of hemorrhagic pituitary apoplexy in an 18 year-old male with previously undiagnosed type 2 diabetes mellitus who presented with unexplained hyperglycemia (glucose 49.2 mmol/l [887 mg/dl]) and obtundation and in whom an initial diagnosis of non-ketotic hyperglycemic coma (NKHC) was made. MRI revealed a heterogeneous mass arising from an expanded sella turcica into the suprasellar cistern. Despite well-controlled glucose levels on continuous insulin infusion, dexamethasone, and initiation of bromoergocriptine (parlodel) therapy, the patient's vision and pupillary responses deteriorated acutely. Following emergency transphenoidal surgery, the patient's vision and mental status improved. Data confirmed preoperative panhypopituitarism; serum prolactin was 396 ng/ml (microg/l). Immunostudies demonstrated tumoral labeling for prolactin, but not for ACTH, GH, TSH, LH, FSH, or P53.
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PMID:Hemorrhagic pituitary apoplexy in an 18 year-old male presenting as non-ketotic hyperglycemic coma (NKHC). 1604 31


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