Abstract P735: QPCR Panel Profiling Reveals MiRNAs That Modulate Microglial Activation in Aged Males Isolated After Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Anik Banerjee ◽  
Anil Kiran Chokkalla ◽  
Julia Shi ◽  
Juneyoung Lee ◽  
Venugopal Reddy Venna ◽  
...  
Keyword(s):  
Social Isolation ◽  
Microglial Activation ◽  
Artery Occlusion ◽  
Post Stroke ◽  
Intracellular Release ◽  
Immune Mediated ◽  
Microglial Phenotype ◽  
Novel Biomarkers ◽  
Underlying Mechanisms ◽  
Cerebral Artery Occlusion

Introduction: Social isolation (SI) after stroke is associated with increased ischemic injury and significantly delayed recovery due to exacerbation of microglial activation and immune mediated pro-inflammatory mechanisms. Studies have identified miRNAs that modulate and regulate this inflammatory transition through inflammasome NLRP3 activation. However, studies examining miRNA-based microglial activation in SI within the neuro-immune landscape are limited. We investigated miRNA profiles in aged mice to provide biomarkers and to identify underlying mechanisms related to microglial activation within the cerebral environment to mitigate this pathological microglial phenotype. Methods: Aged C57BL/6 male mice (18-20 months) were subjected to a 60-minute middle cerebral artery occlusion (MCAO) followed by reperfusion and were assigned to either (SI) or continued pair-housing (PH) immediately after stroke. On day 15, mice were sacrificed, and plasma samples were subjected to microRNAome (miRNAome) analysis. Top miRNAs were identified using bioinformatics frameworks and pathway analysis was performed using KEGG platform. Flow Cytometry (FACS) was performed on brain tissue and blood to determine if stroke or SI leads to changes in microglial and systemic myeloid activation. Results: The whole miRNAome panel analysis revealed 12 differentially expressed miRNAs (FC of 3 or higher) within the plasma following volcano plot and unsupervised hierarchical clustering analysis confirmed by qPCR validation (P< 0.05). Network analysis revealed miR-495-3p as a pivotal node that targeted the largest subset of immune specific genes (P< 0.05); most notable for the inflammasome NLRP3, a regulator of microglial activation. Significant microglial activation was seen in post-stroke SI mice compared to pair-housed cohorts, identified through MHC-II presentation and the intracellular release of pro-inflammatory cytokines. Conclusion: This study provides an overview of the miRNA changes induced by post-stroke isolation. Additionally, these results suggest that there is potential to use plasma-based miRNAs as a source of novel biomarkers. Further, microglial inflammasome specific pathways appear to be involved in post-stroke social isolation.

Abstract T P229: Deletion of Voltage Gated Proton Channel in Microglial Cells is Neurovascular Protective After Ischemic Brain Injury

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Weiguo Li ◽  
Becca Ward ◽  
Mohammed Abdelsaid ◽  
Tianzheng Yu ◽  
Yisang Yoon ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Ischemia Reperfusion ◽  
Hemorrhagic Transformation ◽  
Artery Occlusion ◽  
Proton Channel ◽  
Ros Generation ◽  
Vascular Integrity ◽  
Voltage Gated ◽  
Underlying Mechanisms ◽  
Cerebral Artery Occlusion

Despite the failure of antioxidant treatments in clinical trials, the undoubted role of reactive oxygen species (ROS) in neurovascular damage after ischemic stroke calls for a more targeted approach. ROS production by microglia, the primary resident immune cells in the brain, is a key event of this process in ischemic stroke. Voltage gated proton channel, Hv1, is localized primarily to microglia and sustains NADPH oxidase activity. Deletion of Hv1 is neuroprotective after permanent middle cerebral artery occlusion (MCAO). We hypothesized that Hv1-mediated microglial ROS generation is also critical for vascular integrity and contributes to reperfusion injury after transient ischemic stroke. The wildtype (WT) and Hv1 knockout (KO) rats (n=4) were subjected to permanent or 3/24 h transient MCAO. The neurological deficiency, infarct, hemorrhagic transformation, and edema ratio were assessed. We found that in both permanent and transient MCAO model, KO rats develop smaller infarct, less vascular injury, edema, and hemorrhagic transformation, resulting in better short-term functional outcome. These results suggest that deletion of microglial Hv1 channel is vasculoprotective after ischemia/reperfusion and the underlying mechanisms need to be further studied.

Abstract WP492: Differential Effects of Iron Chelation With Deferoxamine on Post-Stroke Neurovascular Inflammation: Disease and Sex Interactions

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Victoria L Wolf ◽  
Weiguo Li ◽  
Yasir Abdul ◽  
Guangkuo Dong ◽  
Rebecca Ward ◽  
...  
Keyword(s):  
Functional Outcomes ◽  
Microglial Activation ◽  
Iron Chelation ◽  
Artery Occlusion ◽  
Significant Loss ◽  
Cognitive Outcomes ◽  
Mesenchymal Transition ◽  
Differential Effects ◽  
Post Stroke ◽  
Neurovascular Remodeling

We have shown that 1) poor recovery in diabetes is associated with greater hemorrhagic transformation and significant loss of the cerebrovasculature, and 2) iron chelation therapy with deferoxamine (DFX) improves sensorimotor and cognitive outcomes while preventing vasoregression in male diabetic animals after stroke. This study tested the hypotheses that 1) diabetes mediates pathological post-stroke neovascularization in females and 2) DFX attenuates microglial activation and pathological neurovascular remodeling in both sexes. Control and diabetic animals were subjected to embolic middle cerebral artery occlusion (MCAO). DFX (100 mg/kg) or vehicle was given 1hour after MCAO and repeated every 12h for 7 days after stroke. Functional outcomes were assessed over time. Vascular indices, microglial morphology (activation), and neurovascular integrity (IgG and unpolarized Aquaporin-4) were measured at Day 14. Male and female microvascular endothelial cells (BMVECs) treated with iron and/or DFX were tested for viability and endothelial mesenchymal transition (EndMT) markers. DFX preserved vascular volume post-stroke in diabetic males. Stroke did not cause vasoregression in diabetic female animals; however, DFX reduced vascular indices while improving sensorimotor but not cognitive outcomes in both control and diabetic females. Ischemic injury amplified microglial activation and neurovascular remodeling in diabetes while DFX treatment restored these changes to control levels in male diabetic animals but not in females (Table). Female BMVECs grown under diabetic conditions expressed α-SMA and N-cadherin while VE-cadherin was decreased, indicative of EndMT (p<0.05 vs normal glucose). Data suggest that DFX treatment has sex- and disease-dependent effects on post-stroke neovascularization. Additional studies will aim to address the mechanisms by which DFX exerts these differential effects on functional outcomes and neurovascular remodeling.

scholarly journals Impact of Key Nicotinic AChR Subunits on Post-Stroke Pneumococcal Pneumonia

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 253
Author(s):  
Sandra Jagdmann ◽  
Claudia Dames ◽  
Daniel Berchtold ◽  
Katarzyna Winek ◽  
Luis Weitbrecht ◽  
...  
Keyword(s):  
Artery Occlusion ◽  
Experimental Stroke ◽  
Medical Complication ◽  
Α7 Nicotinic Acetylcholine Receptor ◽  
Post Stroke ◽  
Cholinergic Signaling ◽  
Cerebral Artery Occlusion ◽  
Pathogen Clearance ◽  
The Impact ◽  
Alveolar Capillary

Pneumonia is the most frequent severe medical complication after stroke. An overactivation of the cholinergic signaling after stroke contributes to immunosuppression and the development of spontaneous pneumonia caused by Gram-negative pathogens. The α7 nicotinic acetylcholine receptor (α7nAChR) has already been identified as an important mediator of the anti-inflammatory pathway after stroke. However, whether the α2, α5 and α9/10 nAChR expressed in the lung also play a role in suppression of pulmonary innate immunity after stroke is unknown. In the present study, we investigate the impact of various nAChRs on aspiration-induced pneumonia after stroke. Therefore, α2, α5, α7 and α9/10 nAChR knockout (KO) mice and wild type (WT) littermates were infected with Streptococcus pneumoniae (S. pneumoniae) three days after middle cerebral artery occlusion (MCAo). One day after infection pathogen clearance, cellularity in lung and spleen, cytokine secretion in bronchoalveolar lavage (BAL) and alveolar-capillary barrier were investigated. Here, we found that deficiency of various nAChRs does not contribute to an enhanced clearance of a Gram-positive pathogen causing post-stroke pneumonia in mice. In conclusion, these findings suggest that a single nAChR is not sufficient to mediate the impaired pulmonary defense against S. pneumoniae after experimental stroke.

scholarly journals Collateral density, remodeling, and VEGF-A expression differ widely between mouse strains

2007 ◽  
Vol 30 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Dan Chalothorn ◽  
Jason A. Clayton ◽  
Hua Zhang ◽  
Daniel Pomp ◽  
James E. Faber
Keyword(s):  
Recombinant Inbred Strain ◽  
Artery Occlusion ◽  
Mouse Strains ◽  
Artery Ligation ◽  
Cis Acting ◽  
Normal Tissues ◽  
Collateral Growth ◽  
Trait Locus ◽  
Underlying Mechanisms ◽  
Cerebral Artery Occlusion

Substantial variability exists in collateral density and ischemia-induced collateral growth among species. To begin to probe the underlying mechanisms, which are unknown, we characterized two mouse strains with marked differences in both parameters. Immediately after femoral artery ligation, collateral and foot perfusion were lower in BALB/c than C57BL/6 ( P < 0.05 here and below), suggesting fewer pre-existing collaterals. This was confirmed with angiography and immunohistochemistry (∼35% fewer collaterals in the BALB/c's thigh). Recovery of hindlimb perfusion was attenuated in BALB/c, in association with 54% less collateral remodeling, reduced angiogenesis, greater ischemia, and more impaired hindlimb use. Densities of CD45+ and CD4+ leukocytes around collaterals increased similarly, but TNF-α expression was 50% lower in BALB/c, which may contribute to reduced collateral remodeling. In normal tissues, compared with C57BL/6, BALB/c exhibit an altered arterial branching pattern and, like skeletal muscle above, have 30% fewer collaterals in intestine and, remarkably, almost none in pial circulation, resulting in greatly impaired perfusion after cerebral artery occlusion. Ischemic induction of VEGF-A was attenuated in BALB/c. Analysis of a C57BL/6 × BALB/c recombinant inbred strain dataset identified a quantitative trait locus for VEGF-A mRNA abundance at or near the Vegfa locus that associates with lower expression in BALB/c. This suggests a cis-acting polymorphism in the Vegfa gene in BALB/c could contribute to reduced VEGF-A expression and, in turn, the above deficiencies in this strain. These findings suggest these strains offer a model to investigate genetic determinants of collateral formation and growth in ischemia.

Abstract T MP111: Gpr124 Regulates Post-Stroke Cerebrovascular Integrity

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Michael Mancuso ◽  
Junlei Chang ◽  
Carolina Maier-Albers ◽  
Cynthia Kosinski ◽  
Xibin Liang ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Blood Brain Barrier ◽  
Cerebral Artery ◽  
Hemorrhagic Transformation ◽  
Artery Occlusion ◽  
Stroke Model ◽  
Post Stroke ◽  
Adult Mice ◽  
Cerebral Artery Occlusion

Introduction: GPR124/TEM5 is an orphan G-protein coupled receptor (GPCR) with a large extracellular domain. We and others have previously demonstrated that GPR124 exerts CNS-specific angiogenesis regulation with knockout mice exhibiting embryonic lethality from hemorrhagic glomeruloid vascular malformations in forebrain and neural tube (c.f. Kuhnert et al., Science , Nov 12;330(6006):985-9 . (2010)). Hypothesis: GPR124 regulates adult angiogenesis and blood-brain barrier (BBB) integrity during homeostasis or after stroke. Methods: To bypass GPR124 embryonic lethality, we generated GPR124 conditional knockout (cko) mice allowing temporally-regulated deletion. Tamoxifen treatment of GPR124 flox/- ; ROSA-CreER mice versus GPR124 flox/+; ROSA-CreER littermate controls allowed GPR124 cko versus heterozygosity, respectively, in adult mice. GPR124 deletion was followed by analyses of microvascular structure and patterning and blood-brain barrier (BBB) integrity). GPR124 cko mice versus controls were also subjected to 60 minute middle cerebral artery occlusion (MCAO) and effects on stroke volume, survival and microvascular structure assessed. Results: GPR124 deletion in neonatal or adult mice was well-tolerated without impairment of postnatal vascular patterning, BBB maturation or BBB integrity. However, GPR124 cko mice subjected to the middle cerebral artery occlusion (MCAO) stroke model exhibited impaired survival and a profound microvascular hemorrhagic transformation that was confined to the infarct region relative to wild-type controls. GPR124 cko stroke vasculature also exhibited numerous cellular and architectural defects relative to controls that will be discussed. Conclusions: GPR124 deletion is well tolerated in adult mice but results in marked hemorrhagic transformation in the MCAO stroke model. GPR124 represents a novel receptor whose function is essential for cerebrovascular integrity in the post-stroke setting, with attendant therapeutic implications.

scholarly journals A New NF-κB Inhibitor, MEDS-23, Reduces the Severity of Adverse Post-Ischemic Stroke Outcomes in Rats

2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Elina Rubin ◽  
Agnese C. Pippione ◽  
Matthew Boyko ◽  
Giacomo Einaudi ◽  
Stefano Sainas ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Artery Occlusion ◽  
Brain Inflammation ◽  
Neurological Deficits ◽  
Stroke Outcomes ◽  
Post Stroke ◽  
Factor Α ◽  
Cerebral Artery Occlusion ◽  
First Time

Aim: Nuclear factor kappa B (NF-κB) is known to play an important role in the inflammatory process which takes place after ischemic stroke. The major objective of the present study was to examine the effects of MEDS-23, a potent inhibitor of NF-κB, on clinical outcomes and brain inflammatory markers in post-ischemic stroke rats. Main methods: Initially, a Toxicity Experiment was performed to determine the appropriate dose of MEDS-23 for use in animals, as MEDS-23 was analyzed in vivo for the first time. We used the middle cerebral artery occlusion (MCAO) model for inducing ischemic stroke in rats. The effects of MEDS-23 (at 10 mg/kg, ip) on post-stroke outcomes (brain inflammation, fever, neurological deficits, mortality, and depression- and anxiety-like behaviours) was tested in several efficacy experiments. Key findings: MEDS-23 was found to be safe and significantly reduced the severity of some adverse post-stroke outcomes such as fever and neurological deficits. Moreover, MEDS-23 significantly decreased prostaglandin E2 levels in the hypothalamus and hippocampus of post-stroke rats, but did not prominently alter the levels of interleukin-6 and tumor necrosis factor-α. Significance: These results suggest that NF-κB inhibition is a potential therapeutic strategy for the treatment of ischemic stroke.

Abstract P776: Post-Stroke Tenascin-C Induction Mediates the Ischemic Pathogenesis

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Bharath Chelluboina ◽  
Anil Kiran Chokkalla ◽  
Suresh L Mehta ◽  
Saivenkateshkomal Bathula ◽  
Robert J Dempsey ◽  
...  
Keyword(s):  
Matched Control ◽  
Gadobenate Dimeglumine ◽  
Cerebrovascular Diseases ◽  
Artery Occlusion ◽  
Tenascin C ◽  
Post Stroke ◽  
Adult Mice ◽  
Group Sex ◽  
Neurological Surgery ◽  
Cerebral Artery Occlusion

The mechanistic role of Tenascin-C (TNC) in the pathogenesis of acute ischemic stroke is not known despite its prognostic association with cerebrovascular diseases. We currently observed that transient middle cerebral artery occlusion (MCAO) upregulated cerebral TNC mRNA and protein expression between 3h and 24h reperfusion in adult mice of both sexes. We then evaluated the effect of TNC knockdown on ischemic outcome in adult mice of both sexes by treating with either TNC siRNA or control siRNA (intravenous) at 5 min of reperfusion following transient MCAO. TNC siRNA treatment significantly reduced the post-ischemic TNC protein induction tested at 72h reperfusion compared with the sex-matched control siRNA treated cohorts (n=6/group/sex). TNC siRNA cohorts showed significantly improved post-stroke motor function identified by beam walk test and rotarod test between days 1 and 14 of reperfusion compared with the sex-matched control siRNA cohorts (n=7/group/sex). TNC siRNA cohorts of both sexes also showed decreased post-ischemic BBB disruption (evaluated with T1-weighted MRI with gadobenate dimeglumine as contrast agent) and reduced infarction (assessed with T2-weighted MRI) at 3 days of reperfusion compared with the sex-matched control siRNA treated cohorts (n =4/group for BBB and n =12/group/sex for infarct). At day 21 of reperfusion, the survival rate was observed to be higher in the TNC siRNA treated mice compared with the control siRNA treated mice (n =7/group/sex). These studies thus show that induction of TNC during the acute period after stroke might be a mediator of ischemic brain damage and its knockdown is neuroprotective. Importantly this effect is independent of sex. The study was funded by the Department of Neurological Surgery, Univ. of Wisconsin-Madison.

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