Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:A9QXG9 (bcl-2)
 7,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this work was to examine factors that could be involved in the occurrence of apoptosis in rat hearts subjected to coronary occlusion followed by reperfusion. To this end, we studied the expression of the pro- and anti-apoptotic factors, bax and bcl-2, respectively, in reperfused ischemic hearts and in hearts injected with bFGF or saline. In anesthetized rats the left coronary artery was occluded for 45 min, the anesthesia withdrawn and the occlusion removed to allow reperfusion; in sham-operated rats the occlusion was omitted. After 4 hours the rats were decapitated and the heart excised. Sections from the left ventricle were stained with anti-bcl-2-antibody and anti-bax-antibody using the TUNEL method which detects apoptosis. Fragmentation of DNA isolated from reperfused ventricles was examined by agarose electrophoresis. In reperfused hearts no bcl-2 staining was observed in the discrete area in which many cardiomyocyte nuclei were stained by the TUNEL method; outside this area staining for bcl-2 was more marked than in sham-operated rats. Sections from reperfused hearts were stained for bax protein over a wide area including the apoptotic region; sham-operated hearts showed little reaction. Staining for bcl-2 was demonstrable in some nuclei in hearts from saline-injected rats; the numbers were unaffected by i. v. bFGF. Ischemia/reperfusion increases the overall expression of both bcl-2 and bax proteins, but bcl-2 is lost from the reperfused area as indicated by TUNEL staining. Accordingly, the ratio of bcl-2 to bax was reduced in the reperfused area, indicating a pro-apoptotic trend. The marked increase in bcl-2 outside the reperfused area could be a mechanism with which to salvage surviving cardiomyocytes.
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PMID:Coronary reperfusion following ischemia: different expression of bcl-2 and bax proteins, and cardiomyocyte apoptosis. 1193 25

Acute cerebral ischemia causes hypoxic neuronal cell death by necrosis and apoptosis. Expression of anti-apoptotic transgenes in ischemic brain may provide a useful therapeutic strategy for alleviation of postischemic damage. The present study investigates liposome-mediated transfer of the human bcl-2 protein in a rat model of focal transient ischemia due to middle cerebral artery (MCA) occlusion. Two different types of plasmid vectors were used for bcl-2 expression: one driven by the constitutive cytomegalovirus promoter (pCMV) and another based on the hypoxia-inducible human vascular endothelial growth factor promoter (pHRE). Cationic liposome/plasmid DNA complexes (lipoplexes) were injected directly into the cerebrospinal fluid (CSF) of rats immediately after MCA occlusion. The brains of treated and control animals were analyzed 48 h later. Infarct volumes and numbers of apoptotic cells were quantified. Occlusion of the MCA resulted in ipsilateral cerebral infarcts in all study animals. Transfer of the bcl-2 gene resulted in high level widespread protein expression in the case of the pCMV-bcl2 plasmid, while animals treated with the pHRE-bcl2 vector showed lower expression levels of bcl2 which were in addition limited to the ischemic area. Treatment with pCMV-bcl2, but not with pHRE-bcl2, was able to significantly reduce the infarct volume, which was 109 +/- 8 mm(3) for pCMV-bcl2, 152 +/- 29 mm(3) for pHRE-bcl2, and 155 +/- 18 mm(3) for control animals. Animals transfected with either vector showed a significant reduction in numbers of apoptotic cells in the infarct and penumbra area compared with controls. There were no short-term neurological side-effects of the CSF injection of lipoplexes or of bcl-2 expression. In conclusion, the hypoxia-inducible bcl-2 expression mediated by intrathecal lipoplexes may represent a novel, biologically safe and lesion-selective therapeutic approach for neuroprotection after acute cerebral ischemia. DOI: 10.1038/sj/gt/3301676
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PMID:Liposome-mediated transfer of the bcl-2 gene results in neuroprotection after in vivo transient focal cerebral ischemia in an animal model. 1196 Mar 18

Left ventricular (LV) remodeling and heart failure (HF) complicate acute myocardial infarction (AMI) even weeks to months after the initial insult. Apoptosis may represent an important pathophysiologic mechanism causing progressive myocardiocyte loss and LV dilatation even late after AMI. This review will discuss the role of apoptosis according to findings in animal experimental data and observational studies in humans in order to assess clinical relevance, determinants, and mechanisms of myocardial apoptosis and potential therapeutic implications. More complete definition of the impact of myocardiocyte loss on prognosis and of the mechanisms involved may lead to improved understanding of cardiac remodeling and possibly improved patients' care. Mitochondrial damage and bcl-2 to bax balance play a central role in ischemia-dependent apoptosis while angiotensin II and beta(1)-adrenergic-stimulation may be major causes of receptor-mediated apoptosis. Benefits due to treatment with ACE-inhibitors and beta-blockers appear to be in part due to reduced myocardial apoptosis. Moreover, infarct-related artery patency late after AMI may be a major determinant of myocardial apoptosis and clinical benefits deriving from an open artery late post AMI (the "open artery hypothesis") may be, at least in part, due to reduced myocardiocyte loss.
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PMID:Pathophysiologic role of myocardial apoptosis in post-infarction left ventricular remodeling. 1238 91

Alpha-2 adrenoceptor agonists have previously been shown to enhance neuronal survival in an optic nerve mechanical injury model and to protect photoreceptors in a light-induced degeneration model. The purpose of this study was to examine the effect of the alpha-2 adrenoceptor agonist in a pressure-induced retinal ischemia model. Brown-Norway rats were treated systemically or topically with alpha-2 adrenoceptor specific agonist brimonidine. Retinal ischemia was induced by increasing the intraocular pressure to 110 mm Hg for 50 min. The effect of brimonidine on retinal ischemic injury was functionally assessed in the rats 7 d later using electroretinography (ERG). Ischemia-induced retinal cell death was studied using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. We found that brimonidine treatment significantly protected the retina from retinal ischemic injury in a dose- and time-dependent manner. This protection can be achieved either by systemic or topical application and can be blocked by pretreatment with the alpha-2 adrenoceptor antagonist, yohimbine. Using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis, we found that brimonidine can up-regulate the expression of basic fibroblast growth factor, bcl-2 and bcl-xl in the retina. The drug also can activate two major cell survival signaling pathways in the retina: the extracellular-signal-regulated kinases (ERKs) and phosphatidylinositol-3' kinase/protein kinase Akt pathways. All these aforementioned factors may potentially contribute in mediating brimonidine's protective effect in this acute retinal ischemia model.
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PMID:Alpha-2 adrenoceptor agonist protects retinal function after acute retinal ischemic injury in the rat. 1238 29

Recent findings on the induction of anti-apoptotic gene expression in ischemic/reperfused hearts encouraged us to investigate whether ischemic/reperfused hearts may be protected against apoptosis induction. To analyze this hypothesis we performed studies on isolated perfused hearts of rat. For apoptosis induction, hearts were perfused with the NO donor (+/-)-S-nitroso-N-acetylpenicillamine (SNAP, 10 microM) for 30 minutes. Four hours thereafter apoptosis was detected by DNA laddering and TUNEL assay. Under normoperfusion SNAP induced 5.5 +/- 1.4 TUNEL-positive myocytes per tissue section (vs. 1.8 +/- 0.5 in controls). But when hearts were subjected to 20 minutes of no flow ischemia, which was sufficient for energy depletion of the hearts without inducing severe necrotic or apoptotic cell death, reperfusion in the presence of SNAP did not induce apoptosis. To analyze if this mode of protection is a property of the cardiomyocytes, we performed corresponding experiments on ventricular cardiomyocytes of rat. Again, under normoxic conditions SNAP (100 (microM) increased the number of TUNEL-positive cells to 12.6 +/- 4.9 % (vs. 5.4 +/- 0.7 % in controls). But when SNAP was added after 3 h of simulated ischemia, which was sufficient for energy depletion of the cells without inducing apoptotic cell death, the number of apoptotic cells did not increase. The ischemia-induced protection of hearts and cardiomyocytes goes along with an increased expression of several anti-apoptotic genes, mainly of the bcl-2 family. This indicates that ischemic conditions induce an anti-apoptotic gene program in cardiomyocytes, which may also be responsible for the observed anti-apoptotic actions in the intact ischemic/reperfused myocardium.
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PMID:Inhibition of apoptotic responses after ischemic stress in isolated hearts and cardiomyocytes. 1239 10

Whether conventional hypothermic CPB induces myocyte apoptosis in dog hearts and modulation of bcl-2, bcl-xl, bax, bad, and caspase-3 pathways in this setting was investigated. Ten healthy adult dogs were randomized into sham-operated and CPB groups. Samples of left ventricle were obtained before, during and 3 h after CPB. In situ TUNEL was used to detect apoptotic myocytes. Immunohistochemistry and flow cytometry were employed for detection of expressions of bcl-2, bcl-xl, bax and bad proteins. Z-DEVD-AMC substrate cleavage and TBARS methods were used to measure the activity of caspase-3 and the content of lipid peroxide in LV myocardium, respectively. After CPB, the number of apoptotic myocytes in CPB group was significantly increased. The results of immunohistochemistry demonstrated that bcl-2, bcl-xl, bax and bad proteins were constitutionally present on the sarcolemma of the LV myocytes. FACS results showed that, after CPB, expressions of bax and bad in CPB group were significantly upregulated, while the expressions of bcl-2 and bcl-xl were not significantly changed in both groups. The activity of caspase-3 and the content of lipid peroxide in LV myocardium in CPB group were also significantly increased after CPB. The present study shows that there exists myocardiocyte apoptosis in dog hearts undergoing conventional hypothermic CPB and the myocyte apoptosis is initiated by ischemia and performed during reperfusion. Moreover, the CPB-induced myocyte apoptosis was associated with upregulation of expressions of bax and bad proteins, activation of caspase-3 and increase of oxidative stress.
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PMID:Regulatory effect of bcl-2 family proteins in CPB-induced cardiomyocyte apoptosis in dog hearts. 1265 45

The percentage of grafted embryonic DA neurons that survive transplantation is low, estimated at 5-20%. Significant agreement has emerged from the work of research groups worldwide that specific conditions associated with the transplant procedure and post-transplantation interval render grafted mesencephalic cells susceptible to apoptotic death. Detrimental triggers including hypoxia/ischemia, trophic factor withdrawal, and oxidative stress appear to exert the most impact on grafted DA neuron survival. Treatment strategies that aim to reduce or eliminate the triggers of grafted cell death appear to be more successful than approaches that target the intracellular apoptotic cascade. In particular, treatment of mesencephalic cell suspensions with isolated neurotrophic factors (GDNF, BDNF, NT 4/5) as well as glial-derived factors, antioxidant therapies and augmentation of graft vasculature have demonstrated consistent survival promoting effects. Caspase inhibition, although initially quite promising, has not been demonstrated to reliably increase grafted cell survival. Bcl-2 overexpression similarly has yet to prove beneficial, although this may be due to biologically irrelevant levels of bcl-2 present during the critical immediate post-grafting interval. Future strategies will target a "cocktail" approach in which effective treatment agents are combined to maximize grafted DA neuron survival. Refinements in ex vivo transduction parameters will allow for efficient sustained delivery of survival promoting agents to grafted cells. Once identified, the optimal survival-enhancing treatment of grafted primary embryonic DA neurons should also benefit future transplant therapies utilizing alternatively derived DA neurons.
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PMID:Strategies for the augmentation of grafted dopamine neuron survival. 1270 87

The original neuroprotective hypothesis of estrogen was based on the gender difference in brain response to the ischemia-reperfusion injury. Additional clinical reports also suggest that estrogen may improve cognition in patients with Alzheimer disease. 17beta-Estradiol is the most potent endogenous ligand of estrogen, which protects against neurodegeneration in both cell and animal models. Estrogen-mediated neuroprotection is probably mediated by both receptor-dependent and -independent mechanisms. Binding of estrogen such as 17beta-estradiol to estrogen receptors (ERs) activates the homodimers of ER-DNA and its binding to estrogen response elements in the promoter region of genes such as neuronal nitric oxide synthase (NOS1) for regulating gene expression in target brain cells. In addition to the induction of NOS1, estrogen increases the expression of antiapoptotic protein such as bcl-2. Furthermore, our recent observations provide new molecular biologic and pharmacologic evidence suggesting that physiologic concentrations of 17beta-estradiol (<10 nM) activate ERs (ERbeta > ERalpha) and upregulate a cyclic guanosine 5'- monophosphate (cGMP)-dependent thioredoxin (Trx) and MnSOD expression following the induction of NOS1 in human brain-derived SH-SY5Y cells. We thus proposed that the estrogen-mediated gene induction of Trx plays a pivotal role in the promotion of neuroprotection because Trx is a multifunctional antioxidative and antiapoptotic protein. For managing progressive neurodegeneration such as Alzheimer dementia, our estrogen proposal of the signaling pathway of cGMP-dependent protein kinase (PKG) in mediating estrogen-induced cytoprotective genes thus fosters research and development of the new estrogen ligands devoid of female hormonal side effects such as carcinogenesis.
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PMID:Induction of antioxidative and antiapoptotic thioredoxin supports neuroprotective hypothesis of estrogen. 1277

Recent experimental studies have described protective effect of ischemic preconditioning (IPC) on ischemia-reperfusion (I/R) injury of the intestine. We hypothesize that to reach a new point of view on the effect of IPC in intestinal barrier function, the relationship between I/R-induced mucosal injury and apoptosis must first be clarified. The present study was undertaken to investigate the role of IPC on intestinal apoptosis and probable contributions of bcl-2 expression to this process. We also investigated the effect of intestinal IPC on ileal malondyaldihyde levels. Forty-four male Wistar rats were randomized into four groups each consisting of 11 rats: sham-operated control, I/R group (30 min of superior mesenteric artery occlusion), IPC-I/R group (10 min of temporary artery occlusion prior before an ischemic insult of 30 min), and IPC alone group (10 min of preconditioning). Twenty-four hours later, ileum samples were obtained. Ileal malondyaldihyde levels were increased in the I/R group (31.9 +/- 18.8 vs. 106.8 +/- 39.8) but not in the IPC alone and IPC-I/R groups (38.1 +/- 13.6 and 44.7 +/- 12.7; P < 0.01). The number of apoptotic cells was significantly lower in IPC-I/R group than that of I/R group, and these findings were further supported by DNA laddering and M30 findings. Diminished bcl-2 expression observed in the ileal specimens of I/R group was prevented by IPC. Our results indicate that IPC may provide a protective effect on ileal epithelium and that this effect is probably the result of a significant increase in the expression of bcl-2 after the insult. The reversal of apoptosis by IPC might help preserving the vitality of intestinal structures that have a critical function, cessation of which often leads to multiorgan dysfunction syndrome.
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PMID:Ischemic preconditioning reduces intestinal epithelial apoptosis in rats. 1278 17

In order to study the effects of losartan on cardiomyocyte apoptosis following ischemia (0.5 h) and reperfusion (48 h) in vivo and bcl-2 and bax gene expression, TUNEL staining method, immunohistochemistry and in situ hybridization histochemistry (ISHH) were used to monitor the apoptotic cells, mRNA and protein of gene expression, respectively. Image processing system was used to quantitatively dispose the positive metric substance of both immunohistochemistry and ISHH through the average optical density (OD) value. The number of the apoptotic cells were 38 +/- 9 (control group), 0-1 (sham operation group) and 9 +/- 4 (losartan-treated group) in each visual field respectively with the difference among the groups being significant (P < 0.001). OD values of bcl-2 (ISHH) were 0.07425 +/- 0.02029 (control group), 0.05961 +/- 0.009932 (sham operation group) and 0.07619 +/- 0.01445 (losartan-treated group) respectively, while OD values of bcl-2 (immunohistochemistry) were 0.1374 +/- 0.01367 (control group), 0.08510 +/- 0.01862 (sham operation group) and 0.1252 +/- 0.02064 (losartan-treated group). bcl-2 gene expression was increased significantly in the control group and losartan-treated group as compared with sham operation group (P < 0.05). OD value of bax (immunohistochemistry) was 09727 +/- 0.02230 (control group), 0.06182 +/- 0.01430 (sham operation group) and 0.06213 +/- 0.01420 (losartan-treated group). bax gene expression was decreased very significantly in losartan-treated group and sham operation group as compared with control group (P < 0.001). Bcl-2/bax ratio was 1.413 (control group), 1.376 (sham operation group) and 2.016 (losartan-treated group) respectively. The results indicated that losartan might inhibit cardiomyocyte apoptosis following ischemia and reperfusion. The mechanism might be that bax gene expression was inhibited to increase bcl-2/bax ratio.
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PMID:Study on the effects of losartan on cardiomyocyte apoptosis and gene expression after ischemia and reperfusion in vivo in rats. 1284 56


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