Microglial VPS35 deficiency regulates microglial polarization and decreases ischemic stroke-induced damage in the cortex

Abstract Background Vacuolar sorting protein 35 (VPS35), a critical component of retromer, is essential for selective endosome-to-Golgi retrieval of membrane proteins. It is highly expressed in microglial cells, in addition to neurons. We have previously demonstrated microglial VPS35’s functions in preventing hippocampal, but not cortical, microglial activation, and in promoting adult hippocampal neurogenesis. However, microglial VPS35’s role in the cortex in response to ischemic stroke remains largely unclear. Methods We used mice with VPS35 cKO (conditional knockout) in microglial cells and examined and compared their responses to ischemic stroke with control mice. The brain damage, cell death, changes in glial cells and gene expression, and sensorimotor deficits were assessed by a combination of immunohistochemical and immunofluorescence staining, RT-PCR, Western blot, and neurological functional behavior tests. Results We found that microglial VPS35 loss results in an increase of anti-inflammatory microglia in mouse cortex after ischemic stroke. The ischemic stroke-induced brain injury phenotypes, including brain damage, neuronal death, and sensorimotor deficits, were all attenuated by microglial VPS35-deficiency. Further analysis of protein expression changes revealed a reduction in CX3CR1 (CX3C chemokine receptor 1) in microglial VPS35-deficient cortex after ischemic stroke, implicating CX3CR1 as a potential cargo of VPS35 in this event. Conclusion Together, these results reveal an unrecognized function of microglial VPS35 in enhancing ischemic brain injury-induced inflammatory microglia, but suppressing the injury-induced anti-inflammatory microglia. Consequently, microglial VPS35 cKO mice exhibit attenuation of ischemic brain injury response.

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Abstract T MP18: In Vivo Expansion of Regulatory T cells with Interleukin-2/Interleukin-2-antibody Complex Protects against Transient Ischemic Stroke

Stroke ◽

10.1161/str.46.suppl_1.tmp18 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Haiyue Zhang ◽

Peiying Li ◽

Yanqin Gao ◽

Jun Chen ◽

Xiaoming Hu

Keyword(s):

T Cells ◽

Ischemic Stroke ◽

Brain Injury ◽

Regulatory T Cells ◽

Interleukin 2 ◽

Ischemic Brain Injury ◽

Ischemic Brain ◽

Treg Population ◽

Antibody Complex

Background and Purpose: Our previous work documents the transfer of regulatory T cells (Tregs) in rodent models of ischemic stroke protects acute ischemic brain injury by regulating poststroke inflammatory response and thereby ameliorating BBB disruption. However, the low number of Tregs restricts the clinical feasibility of Treg transfer. Recently, in vivo expansion of Tregs with IL-2/IL-2-antibody complex (IL-2/IL-2Ab) was validated protective in autoimmune diseases model,renal ischemia reperfusion model and atherosclerosis. Here we investigate the beneficial effect of IL-2/IL-2Ab on ischemic stroke and decipher the underlying mechanisms. Methods: IL-2/IL-2Ab or isotype IgG was ip injected into C57/BL6 mice for 3 consecutive days. The mice are then subjected to 60-minute middle cerebral artery occlusion (MCAO) or sham operation. Brain infarction, inflammation and neurological performance was assessed up to 7 days after reperfusion. Results: Flow cytometry analysis reveals a marked increase of CD4+CD25+Foxp3+ Tregs in the blood, lymph nodes and spleens collected from IL-2/IL-2Ab-treated mice as compared to those from isotype-treated controls. Such Treg elevation could be observed since 3 days after IL-2/IL-2Ab injection and lasts until 7 days after MCAO. Immunochemistry staining confirms the increased number of Foxp3+ cells in the spleen at 3 days after MCAO in IL-2/IL-2Ab-treated mice. IL-2/IL-2Ab promotes function recovery up to 7 days after stroke, as revealed by significantly improved performance in corner test (n=6-9, ***p<0.001), rotarod test (n=8, **p<0.01), cylinder test (n=8, **p<0.01) and adhesive removal test (n=3, *p<0.05). Quantification of TTC staining and microtubule-associated protein (MAP2) staining shows reductions in brain infarct volume at 3 days (n=5-9,*p<0.05) and 7 days (n=7-9,*p<0.01), respectively, after MCAO. Meanwhile, we observed reduced infiltration of peripheral immune cells (CD3+ T cells, MPO+ neutrophils and F4/80+ macrophages) into the ischemic brain. Conclusions: Our finding suggests that IL-2/IL-2Ab treatment is a novel and clinical feasible immune therapy to expand Treg population in vivo, reduce post-stroke inflammatory responses and protect against ischemic brain injury.

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Abstract TP269: Lncrna-u90926 Aggravates Ischemic Brain Injury via Promoting Neutrophils Infiltration After Experimental Stroke

Stroke ◽

10.1161/str.51.suppl_1.tp269 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Jian Chen ◽

Yun Xu

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Expression Level ◽

Neurological Deficits ◽

Neurological Injury ◽

Experimental Stroke ◽

Ischemic Brain Injury ◽

Triphenyltetrazolium Chloride ◽

Ischemic Brain ◽

Severity Scores

Background: Long non-coding RNAs (LncRNAs) are expressed at high levels in the brain in a variety of neuropathologic conditions, including stroke. However, the potential role of LncRNAs in ischemic stroke-associated microglial biological function and neurological injury remains largely unknown. Methods: Oxygen-glucose deprivation and transient middle cerebral artery occlusion (MCAO) in C57BL/6 mice were used as in vitro and in vivo ischemic stroke models. Microarray analysis was performed to explore the overall expression level changes of LncRNAs. Real-time polymerase chain reaction (RT-qPCR) was used to detect expression level of LncU90926 in brain, plasma and microglia. ShRNA-LncU90926 in lentivirus and microglia specific Adeno-associated virus (AAV) were used to knockdown LncU90926 in vitro and in vivo separately. Infarct volumes and neurological impairments were assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining, Neurological Severity Scores (NSS), rotarod test and grip strength respectively. Immunofluorescence staining and flow cytometry were performed to detect the number of neutrophils recruited to brain. RT-qPCR was used to detect the level of chemokines (CXCL, CCL2) and inflammatory mediators associated with neutrophils (MPO, MMP3 and TIMP1). Results: (1). LncU90926 was markedly up-regulated in the infarcted brain and plasma after MCAO. Both MCAO and OGD treatment induced remarkable up-regulation of LncU90926 in microglia. (2). LncU90926 knockdown definitely attenuated brain infarct size and neurological deficits after ischemic stroke. (3). LncU90926 knockdown in microglia reduced the number of neutrophils recruited to brain, and CXCL1 and CCL2 were down-regulated in both MCAO and OGD models. LncU90926 knockdown also induced reduction of MPO, MMP3 and TIMP1 in the infarcted brain. Conclusions: LncU90926 was up-regulated in microglia after experimental stroke, and aggravates ischemic brain injury through facilitating neutrophils infiltration via up-regulating microglial chemokine.

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EDA-Containing Fibronectin Aggravates Ischemic Brain Injury In Mice

Blood ◽

10.1182/blood.v116.21.330.330 ◽

2010 ◽

Vol 116 (21) ◽

pp. 330-330

Author(s):

Anil Chauhan ◽

Mohammad M Khan ◽

Chintan Gandhi ◽

Neelam Chauhan ◽

Asgar Zaheer ◽

...

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Experimental Model ◽

Vascular Injury ◽

Laser Doppler Flowmetry ◽

Infarct Volume ◽

Neurological Deficits ◽

Ischemic Brain Injury ◽

Doppler Flowmetry ◽

Ischemic Brain

Abstract Abstract 330 Background: Fibronectin (FN) is a dimeric glycoprotein that plays an important role in several cellular processes, such as embryogenesis, malignancy, hemostasis, wound healing and maintenance of tissue integrity. FN is a ligand for many members of the integrin family (e.g. αIIbβ3, α5β1, α4β1, α9β1, αvβ3 and αvβ5) and also binds to thrombosis-related proteins including heparin, collagen and fibrin. FN generates protein diversity as a consequence of alternative processing of a single primary transcript. Two forms of FN exist; soluble plasma FN (pFN), which lacks the alternatively-spliced Extra Domain A (EDA); and insoluble cellular FN (cFN), which contains EDA. FN containing EDA (EDA+FN) is normally absent in plasma of human and mouse but EDA+FN has been found in patients with vascular injury secondary to vasculitis, sepsis, acute major trauma or ischemic stroke. We tested the hypothesis that elevated levels of plasma EDA+FN increase brain injury in an experimental model of ischemic stroke in mice. Model and Method: We used two genetically modified mouse strains: EDA+/+ mice contain optimized spliced sites at both splicing junctions of the EDA exon and constitutively express only EDA+FN, whereas EDA-/- mice contain an EDA-null allele of the EDA exon and express only FN lacking EDA. Control EDAwt/wt mice contain the wild-type FN allele. Transient focal cerebral ischemia was induced by 60 minutes of occlusion of the right middle cerebral artery with a 7.0 siliconized filament in male mice (8-10 weeks in age). Mice were anesthetized with 1–1.5% isoflurane mixed with medical air. Body temperature was maintained at 37°C ± 1.0 using a heating pad. Laser Doppler flowmetry was used to confirm induction of ischemia and reperfusion. At 23 hours after MCAO, mice were evaluated for neurological deficits as a functional outcome and were sacrificed for quantification of infarct volume. For morphometric measurement eight 1 mm coronal sections were stained with 2% triphenyl-2, 3, 4-tetrazolium-chloride (TTC). Sections were digitalized and infarct areas were measured blindly using NIS elements. Result: In EDA+/+ mice the percentage of infarct volume (mean ± SEM: 37.25 ± 4.11, n= 12,) in the ipsilateral (ischemic) hemisphere was increased by approximately two-fold compared to EDA wt/wt mice (mean ± SEM: 22.33 ± 3.39, n=11; P< 0.05, ANOVA) or EDA-/- mice (mean ± SEM: 21.72 ± 2.94, n=9). Regional cerebral blood flow during ischemia was not different among groups as assessed by laser Doppler flowmetry. The percentage increase in infarct volume in the EDA+/+ mice correlated well with severe neurological deficits (motor-deficit assessed by a four-point neurological score scale) compared to EDA wt/wt or EDA-/- mice. Because both thrombosis and inflammation contributes to brain injury during ischemic stroke, we investigated the time to form an occlusive thrombus in ferric-chloride carotid artery injury model by intravital microscopy. EDA+/+ mice demonstrated significantly faster time to occlusion (mean ± SEM: 12.35 ± 1.51 n=12,) compared to EDAwt/wt (Mean ± SEM: 17.27 ± 1.72 min, n=13, P<0.05, ANOVA) or EDA-/- (Mean ± SEM: 15.61 ± 1.76, n=11) mice. Additionally, the inflammatory response in the ischemic region was increased by two fold in EDA+/+ mice compared to EDA wt/wt and EDA-/- mice as sensed by myeloperoxidase activity and immunohistochemical analysis of neutrophils. Conclusion: EDA-containing FN is pro-thrombotic and pro-inflammatory, and aggravates ischemic brain injury in an experimental model of stroke in mice. The presence of EDA+FN in plasma may be a risk factor for vascular injury secondary to ischemic stroke. Disclosures: No relevant conflicts of interest to declare.

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Roles of NAD+, PARP-1, and Sirtuins in Cell Death, Ischemic Brain Injury, and Synchrotron Radiation X-Ray-Induced Tissue Injury

Scientifica ◽

10.1155/2013/691251 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Weihai Ying

Keyword(s):

Cell Death ◽

Brain Injury ◽

Synchrotron Radiation ◽

Brain Damage ◽

Tissue Injury ◽

Ischemic Brain Injury ◽

Biological Processes ◽

Ischemic Brain ◽

X Ray ◽

Parp 1

NAD+plays crucial roles in a variety of biological processes including energy metabolism, aging, and calcium homeostasis. Multiple studies have also shown that NAD+administration can profoundly decrease oxidative cell death and ischemic brain injury. A number of recent studies have further indicated that NAD+administration can decrease ischemic brain damage, traumatic brain damage and synchrotron radiation X-ray-induced tissue injury by such mechanisms as inhibiting inflammation, decreasing autophagy, and reducing DNA damage. Our latest study that applies nano-particles as a NAD+carrier has also provided first direct evidence demonstrating a key role of NAD+depletion in oxidative stress-induced ATP depletion. Poly(ADP-ribose) polymerase-1 (PARP-1) and sirtuins are key NAD+-consuming enzymes that mediate multiple biological processes. Recent studies have provided new information regarding PARP-1 and sirtuins in cell death, ischemic brain damage and synchrotron radiation X-ray-induced tissue damage. These findings have collectively supported the hypothesis that NAD+metabolism, PARP-1 and sirtuins play fundamental roles in oxidative stress-induced cell death, ischemic brain injury, and radiation injury. The findings have also supported “the Central Regulatory Network Hypothesis”, which proposes that a fundamental network that consists of ATP, NAD+and Ca2+as its key components is the essential network regulating various biological processes.

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HDAC9 Silencing Exerts Neuroprotection Against Ischemic Brain Injury via miR-20a-Dependent Downregulation of NeuroD1

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2020.544285 ◽

2021 ◽

Vol 14 ◽

Author(s):

Liangjun Zhong ◽

Jinxiang Yan ◽

Haitao Li ◽

Lei Meng

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Neuronal Apoptosis ◽

Inflammatory Factors ◽

Cerebral Stroke ◽

Inflammatory Factor ◽

Ischemic Brain Injury ◽

Ischemic Brain ◽

Factor Release

Cerebral stroke is an acute cerebrovascular disease that is a leading cause of death and disability worldwide. Stroke includes ischemic stroke and hemorrhagic strokes, of which the incidence of ischemic stroke accounts for 60–70% of the total number of strokes. Existing preclinical evidence suggests that inhibitors of histone deacetylases (HDACs) are a promising therapeutic intervention for stroke. In this study, the purpose was to investigate the possible effect of HDAC9 on ischemic brain injury, with the underlying mechanism related to microRNA-20a (miR-20a)/neurogenic differentiation 1 (NeuroD1) explored. The expression of HDAC9 was first detected in the constructed middle cerebral artery occlusion (MCAO)-provoked mouse model and oxygen-glucose deprivation (OGD)-induced cell model. Next, primary neuronal apoptosis, expression of apoptosis-related factors (Bax, cleaved caspase3 and bcl-2), LDH leakage rate, as well as the release of inflammatory factors (TNF-α, IL-1β, and IL-6) were evaluated by assays of TUNEL, Western blot, and ELISA. The relationships among HDAC9, miR-20a, and NeuroD1 were validated by in silico analysis and ChIP assay. HDAC9 was highly-expressed in MCAO mice and OGD-stimulated cells. Silencing of HDAC9 inhibited neuronal apoptosis and inflammatory factor release in vitro. HDAC9 downregulated miR-20a by enriching in its promoter region, while silencing of HDCA9 promoted miR-20a expression. miR-20a targeted Neurod1 and down-regulated its expression. Silencing of HDAC9 diminished OGD-induced neuronal apoptosis and inflammatory factor release in vitro as well as ischemic brain injury in vivo by regulating the miR-20a/NeuroD1 signaling. Overall, our study revealed that HDAC9 silencing could retard ischemic brain injury through the miR-20a/Neurod1 signaling.

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The role of oxidative stress in perinatal hypoxic-ischemic brain injury

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh1202035v ◽

2012 ◽

Vol 140 (1-2) ◽

pp. 35-41 ◽

Cited By ~ 20

Author(s):

Brankica Vasiljevic ◽

Svjetlana Maglajlic-Djukic ◽

Miroslava Gojnic ◽

Sanja Stankovic

Keyword(s):

Oxidative Stress ◽

Brain Injury ◽

Brain Damage ◽

Ischemic Brain Injury ◽

Ischemic Brain Damage ◽

Ischemic Brain ◽

Hypoxic Ischemic Brain Injury ◽

Gpx Activity ◽

Neurodevelopment Outcome

Introduction. The pathogenesis of perinatal hypoxic-ischemic brain damage is highly complex. Objective. The aim of this study was to assess the role of oxidative stress in hypoxic-ischemic brain injury and subsequent abnormal neurological outcome in infants with perinatal hypoxic-ischemic encephalopathy (HIE). We estimated perinatal oxidative brain damage measuring activity of glutathione peroxidase (GPX) in cerebrospinal fluid (CSF) as an indirect biomarker of free radical production during cerebral hypoxia-ischemia in correlation with the level of intracellular enzyme neuron specific enolase (NSE) in CSF as a biomarker of extend of brain injury. Methods. Ninety neonates (>32 GA) with perinatal HIE were enrolled prospectively. HIE was categorized into three stages according Sarnat and Sarnat clinical scoring system and changes seen on amplitude integrated EEG. CSF for GPX analysis and NSE analysis was taken in the first 72 hours of life. Neurodevelopment outcome was assessed at 12 months of corrected gestational age. Results. GPX activity in CSF was in good relation with clinical stage of HIE (p<0.0001) and GA (p<0.0001) and significantly corresponded with subsequent neurodevelopment outcome (p<0.001). GPX activity in CSF showed a strong correlation with NSE levels in CSF (p<0.001) as the biomarker of extent of brain injury. Conclusion. Our results suggest that oxidative stress might be important contributing factor in perinatal hypoxic-ischemic brain damage, particularly in preterm neonates.

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Severe Perinatal Hypoxic-Ischemic Brain Injury Induces Long-Term Sensorimotor Deficits, Anxiety-Like Behaviors and Cognitive Impairment in a Sex-, Age- and Task-Selective Manner in C57BL/6 Mice but Can Be Modulated by Neonatal Handling

Frontiers in Behavioral Neuroscience ◽

10.3389/fnbeh.2019.00007 ◽

2019 ◽

Vol 13 ◽

Cited By ~ 3

Author(s):

Aida Muntsant ◽

Kalpana Shrivastava ◽

Mireia Recasens ◽

Lydia Giménez-Llort

Keyword(s):

Cognitive Impairment ◽

Brain Injury ◽

Ischemic Brain Injury ◽

Ischemic Brain ◽

Neonatal Handling ◽

Sensorimotor Deficits ◽

Hypoxic Ischemic Brain Injury ◽

And Task

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Abstract TP264: MicroRNA-15a/16-1 Antagomir Ameliorates Ischemic Brain Injury in Experimental Stroke

Stroke ◽

10.1161/str.48.suppl_1.tp264 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Xinxin Yang ◽

Kai Liu ◽

Jun Chen ◽

Ke-Jie Yin

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Therapeutic Potential ◽

Specific Inhibitor ◽

Inflammatory Factors ◽

Experimental Stroke ◽

Separate Experiment ◽

Ischemic Brain Injury ◽

Ischemic Brain ◽

Mrna Targets

MicroRNAs (miRs) are small endogenous RNA molecules that repress gene translation by hybridizing to 3’-UTRs of mRNAs. Accumulating evidence has shown that miRs play a critical regulatory role in the pathogenesis of ischemic stroke. MiR-15a and miR-16-1 are two highly conserved miRs, which act similarly by binding to their common mRNA targets, thus forming both a structural and functional cluster. Dysregulated plasma levels of miR-15a/16-1 have been reported in stroke patients. Inhibition of miR-15a has been shown to protect against myocardial infarction and selected by pharmaceutical companies as one of the most attractive miR-based therapeutics. Up to now, the essential role and therapeutic potential of the miR-15a/16-1 cluster in ischemic stroke are poorly understood. In this study, adult male miR-15a/16-1 knockout and wildtype mice were subjected to 45 min of middle cerebral artery occlusion (MCAO) and 72h of reperfusion. In a separate experiment, miR-15a/16-1 specific inhibitor (antagomir, 30 pmol/g) was injected into tail vein of stroke mice and the animals were allowed to survive for 72h. The neurological scores, brain infarct volume, and edema content were then evaluated and analyzed. To explore the underlying mechanism, inflammatory factors were measured by qPCR or ELISA and anti-apoptotic proteins were examined by western blotting. We found that genetic deletion of miR-15a/16-1 or intravenous delivery of miR-15a/16-1 antagomir significantly reduced cerebral infarct size, decreased brain edema and improved neurological outcomes in stroke mice. Mechanistically, treatment of miR-15a/16-1 antagomir significantly ameliorated the expression of several key inflammatory factors and increased the Bcl-2 and Bcl-w levels in the ischemic brain regions. These results demonstrated that pharmacological inhibition of miR-15a/16-1 reduces ischemic brain injury via both anti-apoptotic and anti-inflammatory mechanisms and the miR-15a/16-1 cluster is a novel therapeutic target for ischemic stroke.

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Abstract WP134: 3K3A-APC Protects Pericyte-deficient Mice From Ischemic Brain Injury

Stroke ◽

10.1161/str.51.suppl_1.wp134 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Yaoming Wang ◽

Mikko Huuskonen ◽

Axel Montagne ◽

Berislav Zlokovic

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Activated Protein C ◽

Artery Occlusion ◽

Ischemic Brain Injury ◽

Neuroprotective Effects ◽

Ischemic Brain ◽

Functional Deficits ◽

Favorable Safety ◽

Cerebral Artery Occlusion

Pericytes play a key role in maintaining the blood-brain barrier (BBB) integrity. BBB disruption occurs during early stages after ischemic stroke. However, the role of pericytes in the pathogenesis of ischemic stroke remains still understudied. 3K3A-APC, a recombinant variant of activated protein C, has shown benefits in preclinical models of ischemic stroke and has favorable safety profile and reduces hemorrhage in Phase 2 study in ischemic stroke patients (RHAPSODY). In the present study, we used PDGFRβ heterozygous knockout (PDGFRβ+/-) mice to investigate the effects of pericyte deficiency on ischemic brain injury using transient proximal middle cerebral artery occlusion (tMCAO). Additionally, we investigated the effects of 3K3A-APC therapy (0.2mg/kg i.v. 4h after stroke) in this model. Compared to controls, pericyte deficiency in PDGFRβ+/- mice resulted in ~35% increase in the infarct and edema volumes, reduction in pericyte coverage from 58% to 25%, and increased IgG and fibrin deposition suggesting accelerated BBB breakdown 24h after stroke. Additionally, PDGFRβ+/- mice showed by 36% more degenerating Fluoro-Jade+ neurons and exhibited accelerated neurobehavioral abnormalities. 3K3A-APC improved neuropathological changes and functional deficits. Our results suggest that pericyte deficiency worsens brain damage and functional outcome after ischemic stroke in mice suggesting that pericytes may play an important role in protecting brain from post-ischemic. We also suggests that 3K3A-APC protects pericyte function in stroked mice which could contribute to its overall neuroprotective effects.

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