Abstract TP98: Genetic Deletion of Kruppel-Like Factor 11 Aggravates Ischemic Brain Injury

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Xuelian Tang ◽  
Kai Liu ◽  
Ke-Jie Yin
Keyword(s):  
Ischemic Stroke ◽  
Protective Factor ◽  
Infarct Volume ◽  
Brain Infarction ◽  
Artery Occlusion ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor ◽  
Neurological Outcomes ◽  
Cerebrovascular Function

Kruppel-like factors (KLFs) are members of the zinc finger family of transcription factors and the function of the KLFs in the central nervous system is largely unexplored. KLF11 is a member of the KLF family and we have previously demonstrated that peroxisome proliferator-activated receptor gamma-mediated cerebral protection during ischemic insults needs recruitment of KLF11 as its critical coactivator. In this study we sought to determine the role of KLF11 itself in cerebrovascular function and the pathogenesis of ischemic stroke. Transient middle cerebral artery occlusion (MCAO) was performed in KLF11 knockout and wild-type control mice, and brain infarction size was analyzed by TTC staining. BBB integrity was assessed by using Evans Blue and TMR-Dextran extravasation assays. KLF11 KO mice exhibited significantly larger brain infarct volume and worse neurological outcomes in response to ischemic insults. Genetic deficiency of KLF11 in mice also significantly aggravated ischemia-induced BBB disruption by increasing cerebrovascular permeability and edema in comparison with wild-type mice. Mechanistically, KLF11 was found to directly regulate several key inflammatory cytokines in the brains of ischemic mice. These findings suggest that KLF11 acts as a novel protective factor in ischemic stroke. Elucidating the functional importance of KLF11 in ischemic process may lead us to discover novel pharmaceutical targets for the development of effective therapies against ischemic stroke.

scholarly journals Hypothermia Protects Against Ischemic Stroke Through Peroxisome-proliferator-activated-receptor Gamma

2021 ◽  
Author(s):  
Feng Jia ◽  
Shuai Shao ◽  
Yanlin Chen ◽  
Jiansong Zhang ◽  
Dilimulati Dilirebati ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Infarct Size ◽  
Cell Viability ◽  
Brain Edema ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Neuronal Cells ◽  
Microglial Cells ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Abstract Background: IS (ischemic stroke) remains to be a global public health burden and urgently demands novel strategies. Hypothermia plays a beneficial role in central nervous system diseases. However, the function of hypothermia in IS has not been elucidated. Here we demonstrated the role of hypothermia in IS and explore the mechanism.Methods: IS phenotype was detected by infarct size and infarct volume as well as brain edema in mice. The neuroinflammation was evaluated by activation of microglial cells and expression of inflammatory genes after ischemia/reperfusion (I/R) and oxygen-glucose deprivation/reperfusion (OGD/R). The apoptosis of neuronal cells was assessed by Tunnel staining, expression of Cleaved Caspase-3 and Bax/Bcl-2, cell viability, and LDH release after I/R and OGD/R. Blood-brain-barrier (BBB) permeability was calculated by Evans blue extravasation, the expression of tight junction proteins and MMP-9, cell viability, and LDH release after I/R and OGD/R. The expression of peroxisome-proliferator-activated-receptor gamma (PPARγ) was detected by western blotting after I/R and OGD/R.Results：Hypothermia significantly reduced the infarct size and infarct volume as well as brain edema after ischemia/reperfusion. Consistency, hypothermia induced attenuated neuroinflammation, apoptosis of neuronal cells, and BBB disruption after I/R and OGD/R. Mechanistic studies revealed that hypothermia protected against IS by upregulating the expression of PPARγ in microglial cells, the effect of hypothermia was reversed by GW9662, a PPARγ inhibitor. Conclusions：Our data showed that hypothermia inhibited the activation of microglial cells and microglial cell-mediated neuroinflammation by upregulating the expression of PPARγ in microglial cells. Targeting hypothermia may be a feasible approach for IS treatment.

Abstract P487: Cerebral Endothelial Cell-Derived Small Extracellular Vesicles Enhance Neurovascular Function and Neurological Recovery in Rat Ischemic Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Chao Li ◽  
Chunyang Wang ◽  
Yi Zhang ◽  
Owais K Alsrouji ◽  
Alex B Chebl ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Therapeutic Effect ◽  
Extracellular Vesicles ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Vessel Occlusion ◽  
Western Blots ◽  
Neurological Outcomes ◽  
Transmission Electron

Background: Treatment of patients with cerebral large vessel occlusion with thrombectomy and tissue plasminogen activator (tPA) often leads to incomplete reperfusion. There is a compelling need to develop therapies to enhance the perfusion and to improve neurological outcomes. Methods: Using rat models of embolic middle cerebral artery occlusion (eMCAO) and transient MCAO (tMCAO), we investigated the effect of small extracellular vesicles (sEVs) derived from healthy rat cerebral endothelial cells (CECs) administered intravenously in combination with tPA (CECs/tPA) and as an acute intraarterial adjunct therapy with mechanical reperfusion on stroke outcomes. Recanalization, cerebral blood flow (CBF), and blood-brain barrier (BBB) permeability were analyzed. MicroRNAs (miRs) and proteins were analyzed in CECs harvested from ischemic rats by RT-PCR and Western blots. Transmission electron microscopy was employed to analyze the brain distribution of CEC-sEVs. The effect of sEVs derived from clots acquired from patients undergone thrombectomy was tested on human CEC permeability. Results: CEC-sEVs/tPA given 4h after eMCAO or CEC-sEVs given upon reperfusion after 2h tMCAO significantly reduced infarct volume by ~36% and ~43%, respectively, and robustly improved neurological outcomes compared with tPA or ischemia/reperfusion alone (n=10 rats/group). CEC-sEVs/tPA and upon reperfusion after eMCAO or tMCAO, resepectively, significantly increased recanalization of the occluded MCA, enhanced CBF and reduced BBB leakage. CEC-sEVs/tPA substantially reduced a network of microRNAs and proteins that mediate thrombosis, coagulation and inflammation in CECs. Moreover, CEC-sEVs intravenously administered crossed the BBB and were internalized by CECs cells, astrocytes, and neurons. Stroke patient-clot derived exosomes impaired human CEC permeability and upregulated pro-inflammatory and -coagulatant proteins, which were blocked by CEC-sEVs. Conclusion: CEC-sEVs have a therapeutic effect on acute ischemic stroke in rats by reducing neurovascular damage. Suppressing the network of pro-thrombotic, -coagulant and -inflammatory microRNAs and proteins in CECs by CEC-sEVs likely contributes to the therapeutic effect of CEC-sEVs.

scholarly journals Adverse Adipose Phenotype and Hyperinsulinemia in Gravid Mice Deficient in Placental Growth Factor

Endocrinology ◽  
2008 ◽  
Vol 149 (5) ◽  
pp. 2176-2183 ◽  
Author(s):  
Bianca Hemmeryckx ◽  
Rita van Bree ◽  
Berthe Van Hoef ◽  
Lisbeth Vercruysse ◽  
H. Roger Lijnen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Adrenergic Receptors ◽  
Growth Factor Receptor ◽  
Placental Growth Factor ◽  
Peroxisome Proliferator ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor ◽  
Adipocyte Hypertrophy ◽  
Endothelial Growth Factor

Pregnancy-induced metabolic changes are regulated by signals from an expanded adipose organ. Placental growth factor (PlGF), acting through vascular endothelial growth factor receptor-1, may be among those signals. There is a steep rise in circulating PlGF during normal pregnancy, which is repressed in gravidas who develop preeclampsia. PlGF-deficiency in mice impairs adipose vascularization and development. Here we studied young-adult PlGF-deficient (PlGF−/−) and wild-type mice on a high-fat diet in the nongravid state and at embryonic day (E) 13.5 or E18.5 of gestation. Litter size and weight were normal, but E18.5 placentas were smaller in PlGF−/− pregnancies. PlGF−/− mice showed altered intraadipose dynamics, with the following: 1) less blood vessels and fewer brown, uncoupling protein (UCP)-1-positive, adipocytes in white sc and perigonadal fat compartments and 2) white adipocyte hypertrophy. The mRNA expression of β3-adrenergic receptors, peroxisome proliferator-activated receptor-γ coactivator-1α, and UCP-1 was decreased accordingly. Moreover, PlGF−/− mice showed hyperinsulinemia. Pregnancy-associated changes were largely comparable in PlGF−/− and wild-type dams. They included expanded sc fat compartments and adipocyte hypertrophy, whereas adipose expression of key angiogenesis/adipogenesis (vascular endothelial growth factor receptor-1, peroxisome proliferator-activated receptor-γ2) and thermogenesis (β3-adrenergic receptors, peroxisome proliferator-activated receptor-γ coactivator-1α, and UCP-1) genes was down-regulated; circulating insulin levels gradually increased during pregnancy. In conclusion, reduced adipose vascularization in PlGF−/− mice impairs adaptive thermogenesis in favor of energy storage, thereby promoting insulin resistance and hyperinsulinemia. Pregnancy adds to these changes by PlGF-independent mechanisms. Disturbed intraadipose dynamics is a novel mechanism to explain metabolic changes in late pregnancy in general and preeclamptic pregnancy in particular.

scholarly journals Three-dimensional cultured mesenchymal stem cells enhance repair of ischemic stroke through inhibition of microglia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuejiao Li ◽  
Yankai Dong ◽  
Ye Ran ◽  
Yanan Zhang ◽  
Boyao Wu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Ischemic Stroke ◽  
Proinflammatory Cytokines ◽  
Infarct Volume ◽  
Brain Lesion ◽  
Three Dimensional ◽  
Artery Occlusion ◽  
Rna Seq ◽  
The Brain

Abstract Background We show previously that three-dimensional (3D) spheroid cultured mesenchymal stem cells (MSCs) exhibit reduced cell size thus devoid of lung entrapment following intravenous (IV) infusion. In this study, we determined the therapeutic effect of 3D-cultured MSCs on ischemic stroke and investigated the mechanisms involved. Methods Rats underwent middle cerebral artery occlusion (MCAO) and reperfusion. 1 × 106 of 3D- or 2D-cultured MSCs, which were pre-labeled with GFP, were injected through the tail vain three and seven days after MCAO. Two days after infusion, MSC engraftment into the ischemic brain tissues was assessed by histological analysis for GFP-expressing cells, and infarct volume was determined by MRI. Microglia in the lesion were sorted and subjected to gene expressional analysis by RNA-seq. Results We found that infusion of 3D-cultured MSCs significantly reduced the infarct volume of the brain with increased engraftment of the cells into the ischemic tissue, compared to 2D-cultured MSCs. Accordingly, in the brain lesion of 3D MSC-treated animals, there were significantly reduced numbers of amoeboid microglia and decreased levels of proinflammatory cytokines, indicating attenuated activation of the microglia. RNA-seq of microglia derived from the lesions suggested that 3D-cultured MSCs decreased the response of microglia to the ischemic insult. Interestingly, we observed a decreased expression of mincle, a damage-associated molecular patterns (DAMPs) receptor, which induces the production of proinflammatory cytokines, suggestive of a potential mechanism in 3D MSC-mediated enhanced repair to ischemic stroke. Conclusions Our data indicate that 3D-cultured MSCs exhibit enhanced repair to ischemic stroke, probably through a suppression to ischemia-induced microglial activation.

scholarly journals Cerebral endothelial cell-derived small extracellular vesicles enhance neurovascular function and neurological recovery in rat acute ischemic stroke models of mechanical thrombectomy and embolic stroke treatment with tPA

2021 ◽  
pp. 0271678X2199298
Author(s):  
Chao Li ◽  
Chunyang Wang ◽  
Yi Zhang ◽  
Owais K Alsrouji ◽  
Alex B Chebl ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Extracellular Vesicles ◽  
Mechanical Thrombectomy ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Therapeutic Effects ◽  
Vessel Occlusion ◽  
Healthy Human ◽  
Stroke Treatment

Treatment of patients with cerebral large vessel occlusion with thrombectomy and tissue plasminogen activator (tPA) leads to incomplete reperfusion. Using rat models of embolic and transient middle cerebral artery occlusion (eMCAO and tMCAO), we investigated the effect on stroke outcomes of small extracellular vesicles (sEVs) derived from rat cerebral endothelial cells (CEC-sEVs) in combination with tPA (CEC-sEVs/tPA) as a treatment of eMCAO and tMCAO in rat. The effect of sEVs derived from clots acquired from patients who had undergone mechanical thrombectomy on healthy human CEC permeability was also evaluated. CEC-sEVs/tPA administered 4 h after eMCAO reduced infarct volume by ∼36%, increased recanalization of the occluded MCA, enhanced cerebral blood flow (CBF), and reduced blood-brain barrier (BBB) leakage. Treatment with CEC-sEVs given upon reperfusion after 2 h tMCAO significantly reduced infarct volume by ∼43%, and neurological outcomes were improved in both CEC-sEVs treated models. CEC-sEVs/tPA reduced a network of microRNAs (miRs) and proteins that mediate thrombosis, coagulation, and inflammation. Patient-clot derived sEVs increased CEC permeability, which was reduced by CEC-sEVs. CEC-sEV mediated suppression of a network of pro-thrombotic, -coagulant, and -inflammatory miRs and proteins likely contribute to therapeutic effects. Thus, CEC-sEVs have a therapeutic effect on acute ischemic stroke by reducing neurovascular damage.

scholarly journals Ezetimibe Attenuates Oxidative Stress and Neuroinflammation via the AMPK/Nrf2/TXNIP Pathway after MCAO in Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Jing Yu ◽  
Wen-na Wang ◽  
Nathanael Matei ◽  
Xue Li ◽  
Jin-wei Pang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ischemic Stroke ◽  
Brain Infarction ◽  
Neutrophil Infiltration ◽  
Artery Occlusion ◽  
Receptor Protein ◽  
Related Factor ◽  
Protective Effects ◽  
Sprague Dawley ◽  
Interacting Protein

Oxidative stress and neuroinflammation play essential roles in ischemic stroke-induced brain injury. Previous studies have reported that Ezetimibe (Eze) exerts antioxidative stress and anti-inflammatory properties in hepatocytes. In the present study, we investigated the effects of Eze on oxidative stress and neuroinflammation in a rat middle cerebral artery occlusion (MCAO) model. One hundred and ninety-eight male Sprague-Dawley rats were used. Animals assigned to MCAO were given either Eze or its control. To explore the downstream signaling of Eze, the following interventions were given: AMPK inhibitor dorsomorphin and nuclear factor erythroid 2-related factor 2 (Nrf2) siRNA. Intranasal administration of Eze, 1 h post-MCAO, further increased the endogenous p-AMPK expression, reducing brain infarction, neurologic deficits, neutrophil infiltration, microglia/macrophage activation, number of dihydroethidium- (DHE-) positive cells, and malonaldehyde (MDA) levels. Specifically, treatment with Eze increased the expression of p-AMPK, Nrf2, and HO-1; Romo-1, thioredoxin-interacting protein (TXNIP), NOD-like receptor protein 3 (NLRP3), Cleaved Caspase-1, and IL-1β were reduced. Dorsomorphin and Nrf2 siRNA reversed the protective effects of Eze. In summary, Eze decreases oxidative stress and subsequent neuroinflammation via activation of the AMPK/Nrf2/TXNIP pathway after MCAO in rats. Therefore, Eze may be a potential therapeutic approach for ischemic stroke patients.

Blocking A1 astrocyte conversion with semaglutide attenuates blood-brain barrier disruption in mice after middle cerebral artery occlusion

2021 ◽  
Author(s):  
Qi Zhang ◽  
Chang Liu ◽  
Rubing Shi ◽  
Huimin Shan ◽  
Lidong Deng ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Signaling Pathways ◽  
Middle Cerebral Artery Occlusion ◽  
Blood Brain Barrier ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Rna Seq ◽  
Neurobehavioral Outcomes ◽  
Cerebral Artery Occlusion

Abstract Background Astrocytes play an essential role in the modulation of blood-brain barrier function. Neurological diseases induce astrocytes to transform into a neurotoxic A1 phenotype, thus exacerbating brain injury. However, the effect of A1 astrocyte on the function of BBB after stroke is unknown. Method: Adult male ICR mice (n = 78) were subjected to 90-minute transient middle cerebral artery occlusion. Immunohistochemical staining of A1 (C3d) and A2 (S100A10) was performed to characterize phenotypic changes of astrocytes overtime after stroke. Glucagon-like peptide-1 receptor agonist semaglutide was intraperitoneally injected into the mice to inhibit A1 astrocyte. Infarct volume, atrophy volume, neurobehavioral outcomes, and BBB permeability were examined. RNA-seq was adopted to explore the potential targets and signaling pathways of A1 astrocytes induced BBB dysfunction. Results Astrocytes assumed the A2 phenotype at the early stage of ischemic stroke but gradually transformed to the A1 phenotype. Semaglutide treatment reduced M1 microglia polarization and A1 astrocytes conversion after ischemic stroke (p < 0.05). Ischemia induced brain infarct volume, atrophy volume and neuroinflammation were reduced in the semaglutide treated mice. Neurobehavioral outcomes were improved compared to the control mice (p < 0.05). Further study demonstrated that semaglutide treatment reduced the gap formation of tight junction proteins ZO-1, claudin-5 and occludin, as well as IgG leakage following three days of ischemic stroke (p < 0.05). In vitro experiments revealed that A1 astrocyte-conditioned medium disrupted BBB integrity. RNA-seq further showed that A1 astrocytes were enriched in inflammatory factors and chemokines, as well as significantly modulating TNF and chemokine signaling pathways, which are closely related to barrier damage. Conclusion We concluded that astrocytes undergo a conversion from A2 phenotype to A1 phenotype overtime after ischemic stroke. A1 astrocytes aggravated BBB disruption, suggesting that block of A1 astrocytes conversion provides a novel strategy for the treatment of ischemic stroke.

Abstract T P237: Effect of Danger Associated Molecular Pattern Receptor Complex Proteins CD24 and Siglec-G on Stroke Outcome and Microglial Responses

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Jonathan R Weinstein ◽  
Josiah Hanson ◽  
Lauren Hood ◽  
Diana Chao ◽  
Sean P Murphy ◽  
...  
Keyword(s):  
Infarct Volume ◽  
High Mobility ◽  
Artery Occlusion ◽  
Receptor Complex ◽  
Wild Type ◽  
Vessel Occlusion ◽  
Doppler Flowmetry ◽  
Cytokines And Chemokines ◽  
Molecular Pattern

Background: Both microglia and Toll-like receptors (TLRs) are critical in stroke pathophysiology. In ischemic brain, microglia sense endogenous TLR agonists (danger associated molecular patterns or DAMPs) and respond with varied immune reactions. CD24 and Siglec-G form a receptor complex that modulates TLR4 function and controls responses to DAMPs. The role of CD24 and Siglec-G in stroke is unknown. Methods: We performed 45 min middle cerebral artery occlusion (MCAO) on 12 - 14 week old wild-type, TLR4-/-, CD24-/- and Siglec-G-/- male mice and assessed total and regional adjusted infarct volumes at 48 hours with 2,3,5-triphenyltetrazolium staining. Number of mice per group was determined by power analysis. Cerebral blood flow was assessed with laser doppler flowmetry. In vitro, we examined the effects of endogenous TLR4 agonists heat shock protein-70 and high mobility group box 1 on cytokine (TNFα, IL-6) and chemokine (CXCL10, CCL5) release from microglia derived from wild-type, TLR4-/-, CD24-/- and Siglec-G-/- mice. Results: Following exclusions for weight, temperature and sub-optimal vessel occlusion/reperfusion, total infarct volumes (mean±SEM) were 51±8 mm3 (n = 21), 51±10 mm3 (n = 8), 28±8 mm3 (n = 13) and 54±8 mm3 (n = 19) in wild-type, TLR4-/-, CD24-/- and Siglec-G-/- mice, respectively (p>0.05, one-way ANOVA). Release of cytokines and chemokines was absent (as expected) in microglia from TLR4-/- mice and differentially regulated in microglia from CD24-/- and Siglec-G-/- mice. Conclusions: Genetic deficiency in TLR4, CD24 or Siglec-G modulated microglial response to endogenous TLR4 agonists but did not significantly alter post-stroke infarct volume.

scholarly journals Intranasal salvinorin A improves neurological outcome in rhesus monkey ischemic stroke model using autologous blood clot

2020 ◽  
pp. 0271678X2093813
Author(s):  
Longfei Wu ◽  
Di Wu ◽  
Jian Chen ◽  
Chunhua Chen ◽  
Tianqi Yao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Rhesus Monkeys ◽  
Infarct Volume ◽  
Blood Clot ◽  
Autologous Blood ◽  
Control Group ◽  
Stroke Model ◽  
Neurological Outcomes ◽  
Observation Period ◽  
Autologous Blood Clot

Salvinorin A (SA) exerts neuroprotection and improves neurological outcomes in ischemic stroke models in rodents. In this study, we investigated whether intranasal SA administration could improve neurological outcomes in a monkey ischemic stroke model. The stroke model was induced in adult male rhesus monkeys by occluding the middle cerebral artery M2 segment with an autologous blood clot. Eight adult rhesus monkeys were randomly administered SA or 10% dimethyl sulfoxide as control 20 min after ischemia. Magnetic resonance imaging was used to confirm the ischemia and extent of injury. Neurological function was evaluated using the Non-Human Primate Stroke Scale (NHPSS) over a 28-day observation period. SA significantly reduced infarct volume (3.9 ± 0.7 cm3 vs. 7.2 ± 1.0 cm3; P =  0.002), occupying effect (0.3 ± 0.2% vs. 1.4 ± 0.3%; P =  0.002), and diffusion limitation in the lesion (−28.2 ± 11.0% vs. −51.5 ± 7.1%; P =  0.012) when compared to the control group. SA significantly reduced the NHPSS scores to almost normal in a 28-day observation period as compared to the control group ( P =  0.005). Intranasal SA reduces infarct volume and improves neurological outcomes in a rhesus monkey ischemic stroke model using autologous blood clot.

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