Abstract 3872: Transgenic HuR in Astrocytes Increases Ischemic Lesion Size in Mice

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Randall S Carpenter ◽  
Cyrus L Hinkson ◽  
Peter H King ◽  
Agnieszka A Ardelt
Keyword(s):  
Cerebral Ischemia ◽  
Mrna Stability ◽  
Lesion Size ◽  
Artery Occlusion ◽  
Translational Efficiency ◽  
Test Analysis ◽  
Ischemic Lesion ◽  
Term Survival ◽  
Novel Target ◽  
The Stability

Introduction: Stroke is a serious neurological disorder that affects more than 800,000 Americans each year. HuR, an mRNA binding protein, regulates gene expression by modulating the stability and translational efficiency of mRNAs containing adenine-uridine rich elements in the 3’ untranslated region. Genes implicated in neuroprotection and post-ischemic repair may be regulated by HuR. The current investigation utilizes transgenic mice engineered to express Flag-HuR in astrocytes using the glial fibrillary acidic protein (GFAP) promoter. We hypothesized that modulation of mRNA stability in astrocytes would change the outcome from transient cerebral ischemia. Methods: Four mouse cohorts were studied: male or female and transgenic (TG) or wild-type (WT). Mice underwent 30-minute transient right middle cerebral artery occlusion (MCAO) and survived for 24 or 72h. Neurological scores were recorded after ischemia and prior to euthanasia, and brain tissue was sectioned for histology and immunolabeling. In a blinded fashion, Flag-HuR expressing nuclei were counted in peri-lesional regions of interest (ROI) and contralateral mirror ROIs, and ischemic/contralateral indices were calculated. Representative lesion size was determined in hematoxylin-eosin sections at the level of Bregma 1.10 mm. Results:HuR-Flag expression: The transgene was expressed in peri-lesional astrocytes. 24h after MCAO, hormonally intact female mice had higher levels of Flag-HuR expression: Flag-HuR index was 5.9 ± 1.9 in females (n = 7) vs. 2.0 ± 0.7 in males (n = 6), p = 0.002, Mann-Whitney rank sum test. 72h after MCAO, TG expression declined in females to levels comparable to those of males. Lesion size: There was no difference in lesion size between sex-matched TG and WT mice 24h post-MCAO, but at 72h lesion size was larger in TG females than WT females: 47% ± 12 (n = 10) vs. 22% ± 11 (n = 5), respectively, p = 0.002, t-test. Analysis of neurological scores, sex hormone levels, and long term survival is ongoing. Discussion: We hypothesized that altering mRNA stability in ischemic astrocytes would change outcome from cerebral ischemia. Initial characterization of TG mice in which HuR was expressed under control of the GFAP promoter showed that ischemia results in peri-lesional upregulation of the transgene, which is more robust in females than males 24h after MCAO and comparable to males 72h after MCAO. Transgene expression correlated with increased lesion size in females 72h after MCAO. While the mechanism of this effect requires elucidation, our results suggest that HuR is a viable novel target for further investigation in cerebral ischemia.

scholarly journals A novel voxel-wise lesion segmentation technique on 3.0-T diffusion MRI of hyperacute focal cerebral ischemia at 1 h after permanent MCAO in rats

2017 ◽  
Vol 38 (8) ◽  
pp. 1371-1383 ◽  
Author(s):  
Chi-Hoon Choi ◽  
Kyung Sik Yi ◽  
Sang-Rae Lee ◽  
Youngjeon Lee ◽  
Chang-Yeop Jeon ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Region Of Interest ◽  
Artery Occlusion ◽  
Lesion Segmentation ◽  
Ischemic Lesion ◽  
Segmentation Technique ◽  
Apparent Diffusion ◽  
Relative Threshold ◽  
Cerebral Ischemic

To assess hyperacute focal cerebral ischemia in rats on 3.0-Tesla diffusion-weighted imaging (DWI), we developed a novel voxel-wise lesion segmentation technique that overcomes intra- and inter-subject variation in apparent diffusion coefficient (ADC) distribution. Our novel technique involves the following: (1) intensity normalization including determination of the optimal type of region of interest (ROI) and its intra- and inter-subject validation, (2) verification of focal cerebral ischemic lesions at 1 h with gross and high-magnification light microscopy of hematoxylin-eosin (H&E) pathology, (3) voxel-wise segmentation on ADC with various thresholds, and (4) calculation of dice indices (DIs) to compare focal cerebral ischemic lesions at 1 h defined by ADC and matching H&E pathology. The best coefficient of variation was the mode of the left hemisphere after normalization using whole left hemispheric ROI, which showed lower intra- (2.54 ± 0.72%) and inter-subject (2.67 ± 0.70%) values than the original. Focal ischemic lesion at 1 h after middle cerebral artery occlusion (MCAO) was confirmed on both gross and microscopic H&E pathology. The 83 relative threshold of normalized ADC showed the highest mean DI (DI = 0.820 ± 0.075). We could evaluate hyperacute ischemic lesions at 1 h more reliably on 3-Tesla DWI in rat brains.

scholarly journals Role for Matrix Metalloproteinase 9 after Focal Cerebral Ischemia: Effects of Gene Knockout and Enzyme Inhibition with BB-94

2000 ◽  
Vol 20 (12) ◽  
pp. 1681-1689 ◽  
Author(s):  
Minoru Asahi ◽  
Kazuko Asahi ◽  
Jae-Chang Jung ◽  
Gregory J. del Zoppo ◽  
M. Elizabeth Fini ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Knockout Mice ◽  
Focal Cerebral Ischemia ◽  
Gene Knockout ◽  
Focal Ischemia ◽  
Lesion Size ◽  
Wild Type ◽  
Systemic Hemodynamic ◽  
Ischemic Lesion ◽  
Mmp Inhibitor

It has been shown recently that matrix metalloproteinases (MMPs) are elevated after cerebral ischemia. In the current study, we investigated the pathophysiologic role for MMP-9 (gelatinase B, EC.3.4.24.35) in a mouse model of permanent focal cerebral ischemia, using a combination of genetic and pharmacologic approaches, Zymography and Western blot analysis demonstrated that MMP-9 protein levels were rapidly up-regulated in brain after ischemic onset. Reverse transcription polymerase chain reaction showed increased transcription of MMP-9. There were no differences in systemic hemodynamic parameters and gross cerebrovascular anatomy between wild type mice and mutant mice with a targeted knockout of the MMP-9 gene. After induction of focal ischemia, similar reductions in cerebral blood flow were obtained. In the MMP-9 knockout mice, ischemic lesion volumes were significantly reduced compared with wild type littermates in male and female mice. In normal wild type mice, the broad spectrum MMP inhibitor BB-94 (batimastat) also significantly reduced ischemic lesion size, However, BB-94 had no detectable protective effect when administered to MMP-9 knockout mice subjected to focal cerebral ischemia. These data demonstrate that MMP-9 plays a deleterious role in the development of brain injury after focal ischemia.

SUTURE SIZE OPTIMIZATION IN THE MODEL OF FOCAL ISCHEMIA IN RATS

2020 ◽  
Author(s):  
Марина Станиславовна Кудабаева ◽  
Андрей Евгеньевич Акулов ◽  
Анна Олеговна Пищелко ◽  
Михаил Васильевич Светлик ◽  
Марина Юрьевна Ходанович
Keyword(s):  
Lesion Size ◽  
Artery Occlusion ◽  
Invasive Procedures ◽  
Ischemic Lesion ◽  
Animal Survival ◽  
Term Experiment ◽  
Surgical Suture ◽  
Long Term Experiment ◽  
Cerebral Artery Occlusion

На модели окклюзии срединой церебральной артерии (MCAO) у крыс исследовано влияние параметров монофиламента, используемого для проведения операции, на объем ишемического поражения мозга. Установлена оптимальная длина наконечника филамента, обеспечивающая такой объем ишемического поражения, который позволяет обеспечить хорошую выживаемость животных в сочетании с другими инвазивными процедурами в хроническом эксперименте. In middle cerebral artery occlusion model (MCAO) in rats surgical suture characteristics were analyzed as parameters that can effect on ischemic lesion size. Optimal suture lenght was assigned for inducing ischemic lesion size that facilitates animal survival in long-term experiment, if MCAO and other invasive procedures are combined.

scholarly journals A Novel Endothelin Antagonist, A-127722, Attenuates Ischemic Lesion Size in Rats With Temporary Middle Cerebral Artery Occlusion

Stroke ◽  
1998 ◽  
Vol 29 (4) ◽  
pp. 850-858 ◽  
Author(s):  
Turgut Tatlisumak ◽  
Richard A. D. Carano ◽  
Kentaro Takano ◽  
Terry J. Opgenorth ◽  
Christopher H. Sotak ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Lesion Size ◽  
Artery Occlusion ◽  
Ischemic Lesion ◽  
Cerebral Artery Occlusion ◽  
Endothelin Antagonist

scholarly journals A Review of Methods to Monitor the Modulation of mRNA Stability

2010 ◽  
Vol 15 (6) ◽  
pp. 609-622 ◽  
Author(s):  
Dominique Cheneval ◽  
Tania Kastelic ◽  
Peter Fuerst ◽  
Christian N. Parker
Keyword(s):  
Mrna Stability ◽  
Posttranscriptional Regulation ◽  
Regulation Of Gene Expression ◽  
Translational Efficiency ◽  
Mrna Levels ◽  
Cis Acting ◽  
Novel Approach ◽  
Specific Mrnas ◽  
Steady State Levels ◽  
The Stability

Posttranscriptional regulation of gene expression is an elaborate and intricate process, constituting an important mechanism for the control of protein expression. During its existence, mRNA is escorted by proteins and other RNAs, which control the maturation, transportation, localization, translational efficiency, and ultimately its degradation. Without changes at the transcription level, mRNA steady-state levels can vary dramatically by just small changes in mRNA stability. By influencing the metabolism of specific mRNAs, the abundance of specific mRNAs can be controlled in organisms from bacteria to mammals. In eukaryotic cells, the control of mRNA stability is exerted through specific cis-acting elements (sequence-specific control elements) and trans-acting factors (mRNA binding proteins and some miRNAs). mRNA stability appears to be a key regulator in controlling the expression of many proteins. Dysregulation of mRNA stability has been associated with human diseases, including cancer, inflammatory disease, and Alzheimer’s. These observations suggest that modulating the stability of specific mRNAs may represent a viable strategy for pharmaceutical intervention. The literature already describes several compounds that influence mRNA stability. Measuring mRNA stability by conventional methods is labor intensive and time-consuming. However, several systems have been described that can be used to screen for modulators of mRNA levels in a high-throughput format. Thus, these assay systems offer a novel approach for screening targets that at present appear to be poorly “drugable.” This review describes the utility of mRNA stability as a novel approach to drug discovery, focusing on assay methods and tool compounds available to monitor mRNA stability. The authors describe mRNA stability assays and issues related to this approach.

scholarly journals Surface-modified engineered exosomes attenuated cerebral ischemia/reperfusion injury by targeting the delivery of quercetin towards impaired neurons

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Lin Guo ◽  
Zhixuan Huang ◽  
Lijuan Huang ◽  
Jia Liang ◽  
Peng Wang ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Reperfusion Injury ◽  
Targeted Delivery ◽  
Ischemia Reperfusion Injury ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Therapeutic Drug ◽  
Cerebral Ischemia Reperfusion ◽  
Cerebral Ischemia Reperfusion Injury

Abstract Background The incidence of ischemic stroke in the context of vascular disease is high, and the expression of growth-associated protein-43 (GAP43) increases when neurons are damaged or stimulated, especially in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). Experimental design We bioengineered neuron-targeting exosomes (Exo) conjugated to a monoclonal antibody against GAP43 (mAb GAP43) to promote the targeted delivery of quercetin (Que) to ischemic neurons with high GAP43 expression and investigated the ability of Exo to treat cerebral ischemia by scavenging reactive oxygen species (ROS). Results Our results suggested that Que loaded mAb GAP43 conjugated exosomes (Que/mAb GAP43-Exo) can specifically target damaged neurons through the interaction between Exo-delivered mAb GAP43 and GAP43 expressed in damaged neurons and improve survival of neurons by inhibiting ROS production through the activation of the Nrf2/HO-1 pathway. The brain infarct volume is smaller, and neurological recovery is more markedly improved following Que/mAb GAP43-Exo treatment than following free Que or Que-carrying exosome (Que-Exo) treatment in a rat induced by MCAO/R. Conclusions Que/mAb GAP43-Exo may serve a promising dual targeting and therapeutic drug delivery system for alleviating cerebral ischemia/reperfusion injury.

scholarly journals LINGO-1 shRNA protects the brain against ischemia/reperfusion injury by inhibiting the activation of NF-κB and JAK2/STAT3

Human Cell ◽  
2021 ◽  
Author(s):  
Jiaying Zhu ◽  
Zhu Zhu ◽  
Yipin Ren ◽  
Yukang Dong ◽  
Yaqi Li ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Nuclear Translocation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Mice Model ◽  
Down Regulation

AbstractLINGO-1 may be involved in the pathogenesis of cerebral ischemia. However, its biological function and underlying molecular mechanism in cerebral ischemia remain to be further defined. In our study, middle cerebral artery occlusion/reperfusion (MACO/R) mice model and HT22 cell oxygen–glucose deprivation/reperfusion (OGD/R) were established to simulate the pathological process of cerebral ischemia in vivo and in vitro and to detect the relevant mechanism. We found that LINGO-1 mRNA and protein were upregulated in mice and cell models. Down-regulation LINGO-1 improved the neurological symptoms and reduced pathological changes and the infarct size of the mice after MACO/R. In addition, LINGO-1 interference alleviated apoptosis and promoted cell proliferation in HT22 of OGD/R. Moreover, down-regulation of LINGO-1 proved to inhibit nuclear translocation of p-NF-κB and reduce the expression level of p-JAK2 and p-STAT3. In conclusion, our data suggest that shLINGO-1 attenuated ischemic injury by negatively regulating NF-KB and JAK2/STAT3 pathways, highlighting a novel therapeutic target for ischemic stroke.

scholarly journals Neuroprotective mechanisms of erythropoietin in a rat stroke model

2020 ◽  
Vol 11 (1) ◽  
pp. 48-59
Author(s):  
Martin Juenemann ◽  
Tobias Braun ◽  
Nadine Schleicher ◽  
Mesut Yeniguen ◽  
Patrick Schramm ◽  
...  
Keyword(s):  
Blood Flow ◽  
Infarct Size ◽  
Cerebral Edema ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Lesion Volume ◽  
Ischemic Lesion ◽  
Human Erythropoietin ◽  
Male Wistar Rats ◽  
Cerebral Artery Occlusion

AbstractObjectiveThis study was designed to investigate the indirect neuroprotective properties of recombinant human erythropoietin (rhEPO) pretreatment in a rat model of transient middle cerebral artery occlusion (MCAO).MethodsOne hundred and ten male Wistar rats were randomly assigned to four groups receiving either 5,000 IU/kg rhEPO intravenously or saline 15 minutes prior to MCAO and bilateral craniectomy or sham craniectomy. Bilateral craniectomy aimed at elimination of the space-consuming effect of postischemic edema. Diagnostic workup included neurological examination, assessment of infarct size and cerebral edema by magnetic resonance imaging, wet–dry technique, and quantification of hemispheric and local cerebral blood flow (CBF) by flat-panel volumetric computed tomography.ResultsIn the absence of craniectomy, EPO pretreatment led to a significant reduction in infarct volume (34.83 ± 9.84% vs. 25.28 ± 7.03%; p = 0.022) and midline shift (0.114 ± 0.023 cm vs. 0.083 ± 0.027 cm; p = 0.013). We observed a significant increase in regional CBF in cortical areas of the ischemic infarct (72.29 ± 24.00% vs. 105.53 ± 33.10%; p = 0.043) but not the whole hemispheres. Infarct size-independent parameters could not demonstrate a statistically significant reduction in cerebral edema with EPO treatment.ConclusionsSingle-dose pretreatment with rhEPO 5,000 IU/kg significantly reduces ischemic lesion volume and increases local CBF in penumbral areas of ischemia 24 h after transient MCAO in rats. Data suggest indirect neuroprotection from edema and the resultant pressure-reducing and blood flow-increasing effects mediated by EPO.

scholarly journals MRI Mouse Brain Data of Ischemic Lesion after Transient Middle Cerebral Artery Occlusion

2017 ◽  
Vol 11 ◽  
Author(s):  
Inge A. Mulder ◽  
Artem Khmelinskii ◽  
Oleh Dzyubachyk ◽  
Sebastiaan de Jong ◽  
Marieke J. H. Wermer ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Mouse Brain ◽  
Cerebral Artery ◽  
Artery Occlusion ◽  
Ischemic Lesion ◽  
Brain Data ◽  
Cerebral Artery Occlusion

scholarly journals Tetracycline Induces Stabilization of mRNA in Bacillus subtilis

2002 ◽  
Vol 184 (4) ◽  
pp. 889-894 ◽  
Author(s):  
Yi Wei ◽  
David H. Bechhofer
Keyword(s):  
Bacillus Subtilis ◽  
Mrna Stability ◽  
The Other ◽  
Leader Region ◽  
Subinhibitory Concentration ◽  
Coding Sequence ◽  
Mrna Stabilization ◽  
Threefold Increase ◽  
The Stability

ABSTRACT The tet(L) gene of Bacillus subtilis confers low-level tetracycline (Tc) resistance. Previous work examining the >20-fold-inducible expression of tet(L) by Tc demonstrated a 12-fold translational induction. Here we show that the other component of tet(L) induction is at the level of mRNA stabilization. Addition of a subinhibitory concentration of Tc results in a two- to threefold increase in tet(L) mRNA stability. Using a plasmid-borne derivative of tet(L) with a large in-frame deletion of the coding sequence, the mechanism of Tc-induced stability was explored by measuring the decay of tet(L) mRNAs carrying specific mutations in the leader region. The results of these experiments, as well as experiments with a B. subtilis strain that is resistant to Tc due to a mutation in the ribosomal S10 protein, suggest different mechanisms for the effects of Tc on translation and on mRNA stability. The key role of the 5" end in determining mRNA stability was confirmed in these experiments. Surprisingly, the stability of several other B. subtilis mRNAs was also induced by Tc, which indicates that addition of Tc may result in a general stabilization of mRNA.

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