scholarly journals Post-stroke Delivery of Valproic Acid Promotes Functional Recovery and Differentially Modifies Responses of Peri-Infarct Microglia

2021 ◽  
Vol 14 ◽  
Author(s):  
Tung-Tai Kuo ◽  
Vicki Wang ◽  
Jui-Sheng Wu ◽  
Yuan-Hao Chen ◽  
Kuan-Yin Tseng
Keyword(s):  
Extracellular Matrix ◽  
Valproic Acid ◽  
Functional Recovery ◽  
Morphological Changes ◽  
Infarct Volume ◽  
Morphological Characteristics ◽  
Matrix Remodeling ◽  
Post Stroke ◽  
Circularity Index ◽  
Galectin 3

The specific role of peri-infarct microglia and the timing of its morphological changes following ischemic stroke are not well understood. Valproic acid (VPA) can protect against ischemic damage and promote recovery. In this study, we first determined whether a single dose of VPA after stroke could decrease infarction area or improve functional recovery. Next, we investigated the number and morphological characteristic of peri-infarct microglia at different time points and elucidated the mechanism of microglial response by VPA treatment. Male Sprague-Dawley rats were subjected to distal middle cerebral artery occlusion (dMCAo) for 90 min, followed by reperfusion. Some received a single injection of VPA (200 mg/kg) 90 min after the induction of ischemia, while vehicle-treated animals underwent the same procedure with physiological saline. Infarction volume was calculated at 48 h after reperfusion, and neurological symptoms were evaluated. VPA didn’t significantly reduce infarct volume but did ameliorate neurological deficit at least partially compared with vehicle. Meanwhile, VPA reduced dMCAo-induced elevation of IL-6 at 24 h post-stroke and significantly decreased the number of CD11b-positive microglia within peri-infarct cortex at 7 days. Morphological analysis revealed that VPA therapy leads to higher fractal dimensions, smaller soma size and lower circularity index of CD11b-positive cells within peri-infarct cortex at both 2 and 7 days, suggesting that VPA has core effects on microglial morphology. The modulation of microglia morphology caused by VPA might involve HDAC inhibition-mediated suppression of galectin-3 production. Furthermore, qPCR analysis of CD11b-positive cells at 3 days post-stroke suggested that VPA could partially enhance M2 subset polarization of microglia in peri-infarct cortex. Analysis of VPA-induced changes to gene expressions at 3 days post-stroke implies that these alternations of the biomarkers and microglial responses are implicated in the upregulation of wound healing, collagen trimmer, and extracellular matrix genes within peri-infarct cortex. Our results are the first to show that a low dose of VPA promotes short-term functional recovery but does not alter infarct volume. The decreases in the expression of both IL-6 and galectin-3 might influence the morphological characteristics and transcriptional profiles of microglia and extracellular matrix remodeling, which could contribute to the improved recovery.

scholarly journals Post-stroke Delivery of Valproic acid Promotes Functional Recovery and Differentially Modifies Responses of Peri-infarct Microglia

2020 ◽  
Author(s):  
Tung-Tai Kuo ◽  
Yuan-Hao Chen ◽  
Vicki Wang ◽  
Jui-Sheng Wu ◽  
Kuan-Yin Tseng
Keyword(s):  
Extracellular Matrix ◽  
Valproic Acid ◽  
Functional Recovery ◽  
Microglial Activation ◽  
Low Dose ◽  
Infarct Volume ◽  
Post Stroke ◽  
Qpcr Analysis ◽  
Circularity Index ◽  
Galectin 3

Abstract Background: Recently, microglia, being the determinant of environment in peri-infarct tissue and strongly influence the potential for neuronal plasticity, has been implicated in post-ischemic secondary injury and functional recovery. However, the specific role of peri-infarct microglia and the timing of its morphological changes following ischemic stroke are not well understood. Valproic acid (VPA) can protect against ischemic damage and promote recovery. These effects are usually attributed, at least partially, to the anti-inflammatory ability of this drug to suppress microglial activation. In this study, we explored whether a low dose of VPA after stroke could modify reactive responses in microglia/macrophages and optimize peri-infarct microenvironments to improve functional recovery.Methods: Male Sprague-Dawley rats were subjected to distal middle cerebral artery occlusion (dMCAo) for 90 minutes, followed by reperfusion. Some received a single injection of VPA (200 mg/kg) 90 minutes after the induction of ischemia, while vehicle-treated animals underwent the same procedure with physiological saline. Infarction volume was calculated at 48 hours after reperfusion, and neurological symptoms were evaluated through 48 hours thereafter. The production of cytokines and biomarkers after insult was determined using enzyme-linked immunosorbent assays (ELISAs) and western blot. The effects of VPA on the activation of peri-infarct CD11b-positive cells were assessed based on cellular density and quality observation of morphology with fractal analysis and circularity index. The expressions of genes within peri-infarct zones at 3 days were determined by RNA-sequencing analysis. To determine whether VPA modulates microglial polarization, gentleMACS Dissociator was used to isolate CD11b-positive cells from the peri-infarct cortex of rats treated with or without VPA 3 days after dMCAo, after which the cells were subjected to qPCR analysis.Results: 200 mg/kg of VPA injected 90 minutes after ischemia induction did not significantly reduce infarct volume but did improve neurological deficit at least partially compared with vehicle. Meanwhile, VPA significantly reduced dMCAo-induced elevation of IL-6 at 24 hours post-stroke and significantly decreased the number of CD11b-positive microglia/macrophages within peri-infarct cortex at 7 but not at 2 days. Morphological analysis revealed that VPA therapy leads to higher fractal dimensions and lower circularity index of CD11b-positive cells within peri-infarct cortex at both 2 days and 7 days, suggesting that VPA has core effects on microglial activation. The attenuation of microglia/macrophage activation caused by VPA might involve HDAC inhibition-mediated suppression of galectin-3 production. Analysis of VPA-induced changes to gene expressions in the peri-infarct cortex at 3 days post-stroke indicated the upregulation of wound healing, collagen trimmer, and extracellular matrix genes. Furthermore, qPCR analysis of CD11b-positive cells suggested that VPA could partially enhance M2 subset polarization of microglia/macrophages in peri-infarct cortex.Conclusions: Our results are the first to show that a low dose of VPA promotes short-term functional recovery but does not alter infarct volume. The decreases in the expression of both IL-6 and galectin-3 might influence the extracellular matrix remodeling and morphological characteristics and transcriptional profiles of microglia/macrophages, which could contribute to the improved recovery.

scholarly journals Vascular Sema3E-Plexin-D1 Signaling Reactivation Promotes Post-stroke Recovery through VEGF Downregulation in Mice

2021 ◽  
Author(s):  
Ri Yu ◽  
Nam-Suk Kim ◽  
Yan Li ◽  
Jin-Young Jeong ◽  
Sang-Joon Park ◽  
...  
Keyword(s):  
Functional Recovery ◽  
Knockout Mice ◽  
Vascular Remodeling ◽  
Infarct Volume ◽  
Brain Infarction ◽  
Adult Brain ◽  
Stroke Recovery ◽  
Neurological Deficits ◽  
Post Stroke ◽  
Vegf Signaling

AbstractPost-stroke vascular remodeling, including angiogenesis, facilitates functional recovery. Proper vascular repair is important for efficient post-stroke recovery; however, the underlying mechanisms coordinating the diverse signaling pathways involved in vascular remodeling remain largely unknown. Recently, axon guidance molecules were revealed as key players in injured vessel remodeling. One such molecule, Semaphorin 3E (Sema3E), and its receptor, Plexin-D1, control vascular development by regulating vascular endothelial growth factor (VEGF) signaling. In this study, using a mouse model of transient brain infarction, we aimed to investigate whether Sema3E-Plexin-D1 signaling was involved in cerebrovascular remodeling after ischemic injury. We found that ischemic damage rapidly induced Sema3e expression in the neurons of peri-infarct regions, followed by Plexin-D1 upregulation in remodeling vessels. Interestingly, Plexin-D1 reemergence was concurrent with brain vessels entering an active angiogenic process. In line with this, Plxnd1 ablation worsened neurological deficits, infarct volume, neuronal survival rate, and blood flow recovery. Furthermore, reduced and abnormal vascular morphogenesis was caused by aberrantly increased VEGF signaling. In Plxnd1 knockout mice, we observed significant extravasation of intravenously administered tracers in the brain parenchyma, junctional protein downregulation, and mislocalization in regenerating vessels. This suggested that the absence of Sema3E-Plexin-D1 signaling is associated with blood–brain barrier (BBB) impairment. Finally, the abnormal behavioral performance, aberrant vascular phenotype, and BBB breakdown defects in Plxnd1 knockout mice were restored following the inhibition of VEGF signaling during vascular remodeling. These findings demonstrate that Sema3E-Plexin-D1 signaling can promote functional recovery by downregulating VEGF signaling in the injured adult brain.

scholarly journals Galectin-3 protects against ischemic stroke by promoting neuro-angiogenesis via apoptosis inhibition and Akt/Caspase regulation

2020 ◽  
pp. 0271678X2093113
Author(s):  
Umadevi V Wesley ◽  
Ian C Sutton ◽  
Katelin Cunningham ◽  
Jacob W Jaeger ◽  
Allan Q Phan ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Rat Brain ◽  
Functional Recovery ◽  
Neuronal Cell ◽  
Vessel Density ◽  
Angiogenic Factor ◽  
Ischemic Lesion ◽  
Post Stroke ◽  
Phosphorylated Akt ◽  
Galectin 3

Post-stroke neurological deficits and mortality are often associated with vascular disruption and neuronal apoptosis. Galectin-3 (Gal3) is a potent pro-survival and angiogenic factor. However, little is known about its protective role in the cerebral ischemia/reperfusion (I/R) injury. We have previously shown significant up-regulation of Gal3 in the post-stroke rat brain, and that blocking of Gal3 with neutralizing antibody decreases the cerebral blood vessel density. Our current study demonstrates that intracerebral local delivery of the Gal3 into rat brain at the time of reperfusion exerts neuroprotection. Ischemic lesion volume and neuronal cell death were significantly reduced as compared with the vehicle-treated MCAO rat brains. Gal3 increased vessel density and neuronal survival after I/R in rat brains. Importantly, Gal3-treated groups showed significant improvement in motor and sensory functional recovery. Gal3 increased neuronal cell viability under in vitro oxygen–glucose deprivation conditions in association with increased phosphorylated-Akt, decreased phosphorylated-ERK1/2, and reduced caspase-3 activity. Gene expression analysis showed down regulation of pro-apoptotic and inflammatory genes including Fas-ligand, and upregulation of pro-survival and pro-angiogenic genes including Bcl-2, PECAM, and occludin. These results indicate a key role for Gal3 in neuro-vascular protection and functional recovery following ischemic stroke through modulation of angiogenic and apoptotic pathways.

scholarly journals Ambroxol Upregulates Glucocerebrosidase Expression to Promote Neural Stem Cells Differentiation Into Neurons Through Wnt/β-Catenin Pathway After Ischemic Stroke

2021 ◽  
Vol 13 ◽  
Author(s):  
Hongfei Ge ◽  
Chao Zhang ◽  
Yang Yang ◽  
Weixiang Chen ◽  
Jun Zhong ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Functional Recovery ◽  
Infarct Volume ◽  
Basic Knowledge ◽  
Brain Disorders ◽  
Potential Mechanism ◽  
Stroke Patients ◽  
Stroke Treatment ◽  
Post Stroke

Ischemic stroke has been becoming one of the leading causes resulting in mortality and adult long-term disability worldwide. Post-stroke pneumonia is a common complication in patients with ischemic stroke and always associated with 1-year mortality. Though ambroxol therapy often serves as a supplementary treatment for post-stroke pneumonia in ischemic stroke patients, its effect on functional recovery and potential mechanism after ischemic stroke remain elusive. In the present study, the results indicated that administration of 70 mg/kg and 100 mg/kg enhanced functional recovery by virtue of decreasing infarct volume. The potential mechanism, to some extent, was due to promoting NSCs differentiation into neurons and interfering NSCs differentiation into astrocytes through increasing GCase expression to activate Wnt/β-catenin signaling pathway in penumbra after ischemic stroke, which advanced basic knowledge of ambroxol in regulating NSCs differentiation and provided a feasible therapy for ischemic stroke treatment, even in other brain disorders in clinic.

scholarly journals The Effects of Exercise Intensity on p-NR2B Expression in Cerebral Ischemic Rats

2012 ◽  
Vol 39 (5) ◽  
pp. 613-618 ◽  
Author(s):  
Anjing Zhang ◽  
Yulong Bai ◽  
Yongshan Hu ◽  
Feng Zhang ◽  
Yi Wu ◽  
...  
Keyword(s):  
Body Weight ◽  
Physical Exercise ◽  
Functional Recovery ◽  
Exercise Intensity ◽  
Treadmill Exercise ◽  
Infarct Volume ◽  
Brain Infarct ◽  
Post Stroke ◽  
Cerebral Ischemic ◽  
Intensity Training

Background:The current study explored the effects of treadmill exercise intensity on functional recovery and hippocampal phospho-NR2B (p-NR2B) expression in cerebral ischemic rats, induced by permanent middle cerebral artery occlusion (MCAO) surgery.Method:Adult male Sprague-Dawley rats were randomly divided into four groups, including sham, no exercise (NE), low intensity training (LIT, v = 15 m/min), and moderate intensity training groups (MIT, v = 20 m/min). At different time points, the hippocampal expressions of p-NR2B and total NR2B were examined. In addition, neurological deficit score (NDS), body weight, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were used to evaluate brain infarct volume as assessments of post-stroke functional recovery. In order to investigate the effect of exercise on survival, the mortality rate was also recorded.Results:The results showed that treadmill exercise significantly decreased hippocampal expression of p-NR2B but didn't change the total NR2B, compared to the NE group on the 3rd, 7th, and 14th days following MCAO surgery. The effect on changes in p-NR2B levels, body weight, and brain infarct volume were more significant in the LIT compared to the MIT group.Discussion and Conclusion:The current findings demonstrate that physical exercise can produce neuroprotective effects, in part by down-regulating p-NR2B expression. Furthermore, the appropriate intensity of physical exercise is critical for post-stroke rehabilitation.

Abstract TP113: Delayed (21 Days) Post Stroke Treatment With RPh201, A Botany-Derived Compound, Improves Neurological Functional Recovery in a Rat Model of Embolic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Chunyang Wang ◽  
Michael Chopp ◽  
Rui Huang ◽  
Yi Zhang ◽  
William Golembieski ◽  
...  
Keyword(s):  
Functional Recovery ◽  
Infarct Volume ◽  
Experimental Models ◽  
Stroke Recovery ◽  
Female Rats ◽  
Male Rats ◽  
Acute Stroke Care ◽  
Stroke Treatment ◽  
Post Stroke ◽  
Male And Female Rats

Introduction: Despite the recent advances in the acute stroke care, treatment options for long-term disability are limited. RPh201 is a botany-derived bioactive compound that has been shown to exert beneficial effects in various experimental models of neural injury. However, the effect of RPh201 on stroke recovery has not been investigated. The present study evaluated the effect of RPh201 on functional recovery after stroke. Methods: Young adult Wistar rats subjected to embolic middle cerebral artery occlusion (MCAO) were randomized into the following experimental groups stratified by sex (n=20/group): 1) RPh201 treatment, and 2) vehicle (cottonseed oil). RPh201 (20 μl) or vehicle were subcutaneously administered twice a week for 16 consecutive weeks starting at 21 days after MCAO. An array of behavioral tests were performed during 120 days after treatment initiation. Results: Male, but not female, ischemic rats treated with RPh201 exhibited significant (p<0.05) improvement of neurological function measured by adhesive removal test, foot-fault test, and modified neurological severity score at 90 and 120 days after initiation of treatment. Immunohistochemistry analysis showed that RPh201 treatment robustly increased neurofilament heavy chain positive axons and myelin basic protein densities in the peri-infarct area by 61% and 31% in the male rats, respectively, when compared to the vehicle treatment, which were further confirmed by Western blot analysis. The RPh201 treatment did not reduce infarct volume in both male and female rats. Conclusions: Our data demonstrated that RPh201 has a therapeutic effect on improvement of functional recovery in male ischemic rats even when the treatment was initiated 21 days post stroke. Enhanced axonal and myelination densities by RPh201 in ischemic brain may contribute to improved stroke recovery.

Role of the matrixin MMP-2 in multicellular organization of adipocytes cultured in basement membrane components

1997 ◽  
Vol 272 (3) ◽  
pp. C937-C949 ◽  
Author(s):  
L. M. Brown ◽  
H. L. Fox ◽  
S. A. Hazen ◽  
K. F. LaNoue ◽  
S. R. Rannels ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Basement Membrane ◽  
Conditioned Medium ◽  
Morphological Changes ◽  
Cluster Formation ◽  
Three Dimensional ◽  
Matrix Metalloproteinase 2 ◽  
Matrix Remodeling ◽  
Gelatinase Activity ◽  
Membrane Components

Primary rat adipocytes cultured in basement membrane component gels migrated and organized into large, three-dimensional, multicellular clusters. Gross morphological changes seen during this reorganization are described. The rate of cluster formation decreased with age of the rats and was stimulated by insulin in older, but not in younger rats. Echistatin, a disintegrin, partially inhibited the formation of multicellular clusters in a concentration-dependent fashion (50% inhibitory concentration approximately 10 nM). The original extracellular matrix was initially remodeled and eventually destroyed by the time large multicellular clusters were observed. This implied that one or more matrix-degrading protease(s) were being secreted. Adipocyte-conditioned medium was found to contain a divalent cation-sensitive gelatinase activity at approximately 72 and/or approximately 62 kDa. The elution profile of this activity from gelatin-Sepharose 4B was similar to matrix metalloproteinase 2 (MMP-2, a 72-kDa matrixin with a 62-kDa mature form), and the dimethyl sulfoxide eluant from these columns contained MMP-2 immunoreactivity. MMP-2 concentration and activity were greater in conditioned medium from young than from older animals; however, insulin did not affect the amount of MMP-2 in adipocyte-conditioned media. The matrixin inhibitor 1,10-phenanthroline not only blocked gelatinase activity in zymograms but also prevented extracellular matrix remodeling and destruction, as well as adipocyte migration and the formation of cell-cell contacts in adipocyte cultures. These observations are consistent with the hypothesis that the matrixin MMP-2 is secreted by adipocytes. Whereas matrixin activity alone may not be sufficient for the formation of multicellular clusters, the data indicate that it may have a requisite role in this process.

Abstract 43: Neuroprotective Effects of Inhibition of α5β1 Integrin Following Experimental Stroke: A Dual Center Pre-Clinical Study

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Danielle Edwards ◽  
Biav Reber Kittani ◽  
Gillian Grohs ◽  
Mhairi Macrae ◽  
Justin F Fraser ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Functional Recovery ◽  
Infarct Volume ◽  
Experimental Stroke ◽  
Β1 Integrin ◽  
Integrin Receptor ◽  
Post Stroke ◽  
Enhanced Mri ◽  
Bbb Permeability ◽  
Α5β1 Integrin

Blood-brain barrier (BBB) dysfunction after ischemic stroke exacerbates brain damage by contributing to edema and inflammation. The β1 integrin receptor family may contribute to this dysfunction via alteration of BBB-forming tight junction proteins. We hypothesize that inhibition of the β1 integrin receptor subtype α5β1, which is acutely expressed in infarct and peri-infarct vasculature after experimental stroke, reduces BBB permeability, reduces infarct volume, and improves functional recovery. A randomized and blinded trial was conducted using transient middle cerebral artery occlusion (MCAO) in mice (60 min; n=8) and rats (90 min; n=15) in two independent laboratories. ATN-161 (α5β1 inhibitor; 1 mg/kg) was administered IV immediately upon reperfusion and on post-stroke day 1 and 2. Infarct volume was determined by cresyl violet (mice) and T 2 weighted MRI (rat) at day 3 post MCAO. Steady state contrast enhanced MRI was used to assess BBB breakdown in rats at day 3. ATN-161 resulted in a significant reduction in infarct volume in both mice and rats when measured at post-stroke day 3 (p<0.001). BBB permeability was decreased upon ATN-161 treatment in vivo as determined by reduced IgG and claudin-5 immunostaining in mice and reduced extent of Gadolinium enhanced MRI signal change in rats. Behavioral tests (open field, rotorod, sticky label and 28 point neuroscore), demonstrated significantly improved functional recovery in both mice and rats following treatment with ATN-161. Finally, in vitro studies where stroke was simulated using oxygen and glucose deprivation or TNF-α, ATN-161 (10 μM) treatment demonstrated decreased barrier permeability as measured by trans-endothelial cell electrical resistance, FITC-dextran permeability, and claudin-5 immunocytochemistry. Collectively, our results demonstrate that post-stroke inhibition of α5β1 integrin with the small peptide ATN-161 profoundly reduces infarct volume, improves functional outcome and decreases BBB permeability in both mice and rats using two different ischemic stroke models. Therefore, inhibition of α5β1 by ATN-161 could represent a novel stroke therapeutic target worthy of further investigation.

scholarly journals Galectin-3 preserves renal tubules and modulates extracellular matrix remodeling in progressive fibrosis

2011 ◽  
Vol 300 (1) ◽  
pp. F245-F253 ◽  
Author(s):  
Daryl M. Okamura ◽  
Katie Pasichnyk ◽  
Jesus M. Lopez-Guisa ◽  
Sarah Collins ◽  
Daniel K. Hsu ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Early Time ◽  
Interstitial Cells ◽  
Renal Tubular Cell ◽  
Renal Tubules ◽  
Matrix Remodeling ◽  
Wild Type ◽  
Cytochrome C Release ◽  
Chronic Injury ◽  
Galectin 3

Renal tubular cell apoptosis is a critical detrimental event that leads to chronic kidney injury in association with renal fibrosis. The present study was designed to investigate the role of galectin-3 (Gal-3), an important regulator of multiple apoptotic pathways, in chronic kidney disease induced by unilateral ureteral obstruction (UUO). After UUO, Gal-3 expression significantly increased compared with basal levels reaching a peak increase of 95-fold by day 7. Upregulated Gal-3 is predominantly tubular at early time points after UUO but shifts to interstitial cells as the injury progresses. On day 14, there was a significant increase in TdT-mediated dUTP nick end labeling-positive cells (129%) and cytochrome c release (29%), and a decrease in BrdU-positive cells (62%) in Gal-3-deficient compared with wild-type mice. The degree of renal damage was more extensive in Gal-3-deficient mice at days 14 and 21, 35 and 21% increase in total collagen, respectively. Despite more severe fibrosis, myofibroblasts were significantly decreased by 58% on day 14 in the Gal-3-deficient compared with wild-type mice. There was also a corresponding 80% decrease in extracellular matrix synthesis in Gal-3-deficient compared with wild-type mice. Endo180 is a recently recognized receptor for intracellular collagen degradation that is expressed by interstitial cells during renal fibrogenesis. Endo180 expression was significantly decreased by greater than 50% in Gal-3-deficient compared with wild-type mice. Taken together, these results suggested that Gal-3 not only protects renal tubules from chronic injury by limiting apoptosis but that it may lead to enhanced matrix remodeling and fibrosis attenuation.

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