Therapeutic benefit of intravenous administration of bone marrow stromal cells after cerebral ischemia in rats

Transplantation of miR-193b-3p-Transfected BMSCs Improves Neurological Impairment after Traumatic Brain Injury through S1PR3-Mediated Regulation of the PI3K/AKT/mTOR Signaling Pathway

The aim of the present study was to explore the molecular mechanisms by which miR-193b-3p-trans-fected bone marrow mesenchymal stem cells (BMSCs) transplantation improves neurological impairment after traumatic brain injury (TBI) through sphingosine-1-phosphate receptor 3 (S1PR3)-mediated regulation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway at the cellular and animal levels. BMSCs were transfected with miR-193b-3p. A TBI cell model was established by oxygen-glucose deprivation (OGD)-induced HT22 cells, and a TBI animal model was established by controlled cortical impact (CCI). Cell apoptosis was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL), and cell activity was detected by a cell counting kit 8 (CCK-8) assay. Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression of related proteins and genes. In this study, transfection of miR-193b-3p into BMSCs significantly enhanced BMSCs proliferation and differentiation. Transfection of miR-193b-3p reduced the levels of the interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-alpha (TNF-α) inflammatory factors in cells and mouse models, and it inhibited neuronal apoptosis, which alleviated OGD-induced HT22 cell damage and neural function damage in TBI mice. Downstream experiments showed that miR-193b-3p targeting negatively regulated the expression of S1PR3, promoted the activation of the PI3K/AKT/mTOR signaling pathway, and inhibited the levels of apoptosis and inflammatory factors, which subsequently improved OGD-induced neuronal cell damage and nerve function damage in TBI mice. However, S1PR3 overexpression or inhibition of the PI3K/AKT/mTOR signaling pathway using the IN-2 inhibitor weakened the protective effect of miR-193b-3p-transfected BMSCs on HT22 cells. Transplantation of miR-193b-3p-transfected BMSCs inhibits neurological injury and improves the progression of TBI in mice through S1PR3-mediated regulation of the PI3K/AKT/mTOR pathway.

Sodium Danshensu ameliorates cerebral ischemia/reperfusion injury by inhibiting CLIC4/NLRP3 inflammasome-mediated endothelial cell pyroptosis

Endothelial pyroptosis promotes cerebral ischemia/reperfusion injury (CIRI). Sodium Danshensu (SDSS) has been shown to attenuate CIRI and have anti-inflammatory properties in endothelial cells. However, the mechanism and effect of SDSS on alleviating endothelial pyroptosis after CIRI remains poorly understood. Thus, we aimed to investigate the efficacy and mechanism of SDSS in reducing endothelial pyroptosis. It has been shown that SDSS administration inhibited NLRP3 inflammasome-mediated pyroptosis. As demonstrated by protein microarrays, molecular docking, CETSA and ITDRFCETSA , SDSS bound strongly to CLIC4. Furthermore, SDSS can decrease its expression and inhibit its translocation. Its effectiveness was lowered by CLIC4 overexpression but not by knockdown. Overall The beneficial effect of SDSS against CIRI in this study can be ascribed to blocking endothelial pyroptosis by binding to CLIC4 and then inhibiting chloride efflux-dependent NLRP3 inflammasome activation.

Hematopoietic Endothelial Progenitor cells enhance motor function and cortical motor map integrity following cerebral ischemia

Background

Hematopoietic stem cells (HSC) are recruited to ischemic areas in the brain and contribute to improved functional outcome in animals. However, little is known regarding the mechanisms of improvement following HSC administration post cerebral ischemia. To better understand how HSC effect post-stroke improvement, we examined the effect of HSC in ameliorating motor impairment and cortical dysfunction following cerebral ischemia.

Methods

Baseline motor performance of male adult rats was established on validated motor tests. Animals were assigned to one of three experimental cohorts: control, stroke, stroke + HSC. One, three and five weeks following a unilateral stroke all animals were tested on motor skills after which intracortical microstimulation was used to derive maps of forelimb movement representations within the motor cortex ipsilateral to the ischemic injury.

Results

Stroke + HSC animals significantly outperformed stroke animals on single pellet reaching at weeks 3 and 5 (28±3% and 33±3% versus 11±4% and 17±3%, respectively, p < 0.05 at both time points). Control animals scored 44±1% and 47±1%, respectively. Sunflower seed opening task was significantly improved in the stroke + HSC cohort versus the stroke cohort at week five-post stroke (79±4 and 48±5, respectively, p < 0.05). Furthermore, Stroke + HSC animals had significantly larger forelimb motor maps than animals in the stroke cohort. Overall infarct size did not significantly differ between the two stroked cohorts.

Conclusion

These data suggest that post stroke treatment of HSC enhances the functional integrity of residual cortical tissue, which in turn supports improved behavioral outcome, despite no observed reduction in infarct size.

Electroacupuncture Inhibits Neural Ferroptosis in Rat Model of Traumatic Brain Injury via Activating System Xc-/GSH/GPX4 Axis

BACKGROUND

Ferroptosis is an iron-dependent regulating programmed cell death discovered recently that has been receiving much attention in traumatic brain injury (TBI). xCT, a major functional subunit of Cystine/glutamic acid reverse transporter (System Xc-), promotes cystine intake and glutathione biosynthesis, thereby protecting against oxidative stress and ferroptosis.

OBJECTIVE

The intention of this research was to verify the hypothesis that electroacupuncture (EA) exerted an anti-ferroptosis effect via an increase in the expression of xCT and activation of the System Xc-/GSH/GPX4 axis in cortical neurons of TBI rats.

METHODS

After the TBI rat model was prepared, animals received EA treatment at GV20, GV26, ST36 and PC6, for 15 min. The xCT inhibitor Sulfasalazine (SSZ) was administered 2h prior to model being prepared. The degree of neurological impairment was evaluated by means of TUNEL staining and the modified neurological severity score (mNSS). Specific indicators of ferroptosis (Ultrastructure of mitochondria, Iron and ROS) were detected by transmission electron microscopy (TEM), Prussian blue staining (Perls stain) and flow cytometry (FCM), respectively. GSH synthesis and metabolism-related factors in the content of the cerebral cortex were detected by an assay kit. Real-time quantitative PCR (RT-QPCR), Western blot (WB), and immunofluorescence (IF) were used for detecting the expression of System Xc-/GSH/GPX4 axisrelated proteins in injured cerebral cortex tissues.

RESULTS

EA successfully relieved nerve damage within 7 days after TBI, significantly inhibited neuronal ferroptosis, upregulated the expression of xCT and System Xc-/GSH/GPX4 axis forward protein and promoted glutathione (GSH) synthesis and metabolism in the injured area of the cerebral cortex. However, aggravation of nerve damage and increased ferroptosis effect were found in TBI rats injected with xCT inhibitors.

CONCLUSIONS

EA inhibits neuronal ferroptosis by up-regulated xCT expression and by activating System Xc-/GSH/GPX4 axis after TBI, confirming the relevant theories regarding the EA effect in treating TBI and providing theoretical support for clinical practice.

Dexmedetomidine Alleviates Brain Ischemia/Reperfusion Injury by Regulating Metastasis-associated Lung Adenocarcinoma Transcript 1/MicroRNA-140-5p/ Nuclear Factor Erythroid-derived 2-like 2 Axis

BACKGROUND

Dexmedetomidine (Dex) is widely used in perioperative anesthesia, and recent studies have reported that it protects organs from ischemia/reperfusion (I/R) injury.

OBJECTIVES

This study was performed to investigate the role of Dex in alleviating cerebral I/R injury and its regulatory effects on metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/microRNA-140-5p (miR-140-5p)/nuclear factor erythroid-derived 2-like 2 (Nrf2) axis.

METHODS

In vivo rat middle cerebral artery occlusion (MCAO) model and in vitro oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced neuronal injury model were constructed. Dex was injected into the animals or used to culture HT22 cells to observe the pharmacological effects. The neurological defect, brain water content, infarct volume of the rats, and neuron viability were evaluated. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) were detected. Besides, the regulatory effects of Dex on MALAT1, miR-140-5p, and Nrf2 expression levels and regulatory relationships among them were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and dual- luciferase reporter assay.

RESULTS

Dex significantly alleviated the neurological injury of rats with MCAO and promoted the viability of neurons. Dex treatment suppressed miR-140-5p expression, but elevated MALAT1 and Nrf2 expressions. MALAT1 knockdown down-regulated Nrf2 expression and promoted oxidative stress in neurons. Additionally, miR-140-5p directly targeted Nrf2, and it also functioned as a downstream target miRNA of MALAT1.

CONCLUSION

Dex, via regulating MALAT1/miR-140-5p/Nrf2 axis, plays a neuroprotective role against I/R-induced brain injury.

MiR-199a-5p enhances neuronal differentiation of neural stem cells and promotes neurogenesis by targeting Cav-1 after cerebral ischemia

AIMS

MicroRNAs (miRs) are involved in endogenous neurogenesis, enhancing of which has been regarded as a potential therapeutic strategy for ischemic stroke treatment; however, whether miR-199a-5p mediates postischemic neurogenesis remains unclear. This study aims to investigate the proneurogenesis effects of miR-199a-5p and its possible mechanism after ischemic stroke.

METHODS

Neural stem cells (NSCs) were transfected using Lipofectamine 3000 reagent, and the differentiation of NSCs was evaluated by immunofluorescence and Western blotting. Dual-luciferase reporter assay was performed to verify the target gene of miR-199a-5p. MiR-199a-5p agomir/antagomir were injected intracerebroventricularly. The sensorimotor functions were evaluated by neurobehavioral tests, infarct volume was measured by toluidine blue staining, neurogenesis was detected by immunofluorescence assay, and the protein levels of neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), caveolin-1 (Cav-1), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) were measured by Western blotting.

RESULTS

MiR-199a-5p mimic enhanced neuronal differentiation and inhibited astrocyte differentiation of NSCs, while a miR-199a-5p inhibitor induced the opposite effects, which can be reversed by Cav-1 siRNA. Cav-1 was through the dual-luciferase reporter assay confirmed as a target gene of miR-199a-5p. miR-199a-5p agomir in rat stroke models manifested multiple benefits, such as improving neurological deficits, reducing infarct volume, promoting neurogenesis, inhibiting Cav-1, and increasing VEGF and BDNF, which was reversed by the miR-199a-5p antagomir.

CONCLUSION

MiR-199a-5p may target and inhibit Cav-1 to enhance neurogenesis and thus promote functional recovery after cerebral ischemia. These findings indicate that miR-199a-5p is a promising target for the treatment of ischemic stroke.

Neuroprotective effects of oxytocin against ischemic stroke in rats by blocking glutamate release and CREB-mediated DNA hypermethylation

Glutamate plays a crucial role in cognitive impairments after ischemic stroke. There is a scarcity of information about how glutamate-induced activation of cAMP-response element binding (CREB) signaling pathway regulates both the negative and positive regulators of synaptic plasticity. Recent studies have demonstrated the involvement of prominent epigenetic repressors, such as MeCP2 and DNMTs, in stroke. Neuroprotective effects of oxytocin against ischemia have been previously reported, while the underlying mechanism is still elusive. In this research, the possible role of CREB-mediated DNA hypermethylation and the potential mechanism of oxytocin in a rat model of permanent middle cerebral artery occlusion (pMCAO) were assessed. Adult male Sprague-Dawley rats were pretreated with intraperitoneal injection of oxytocin at the onset of pMCAO. The effects of oxytocin on spines and the expression levels of synaptic genes were determined. The regulatory effects of oxytocin on glutamate level, N-methyl-D-aspartate receptors (NMDARs), its downstream CREB pathway, and global or gene-specific DNA methylation status were evaluated by immunofluorescence, co-immunoprecipitation, and chromatin immunoprecipitation, respectively. We found that CREB could act as a common transcription factor for MeCP2 and DNMT3B after ischemic stroke. Oxytocin dose-dependently deactivated NR2B-related CaM-CREB pathway and inhibited DNA hypermethylation at the CpG islands of Ngf gene in pMCAO-operated rats. Moreover, oxytocin prevented pMCAO-induced reduction in the number of spines and neural cells. DNA hypermethylation in Ngf gene contributed to the cognitive deficits post-stroke. The neuroprotective effects of oxytocin against ischemia could be attributed to inhibiting glutamate release, providing additional evidence on the mechanism of oxytocin against ischemic stroke.

Effect of electrode configuration in electroacupuncture on ischemic stroke treatment in rats

Background and aim

This study investigated the effect of the electrode configuration on EA treating ischemic stroke.

Experimental procedure

An ischemic stroke rat model was established. In the EA-P group, the anodes of EA were placed on the BL7 and BL8 acupoints of the lesioned, and the cathodes were placed on the BL7 and BL8 acupoints of the nonlesioned hemispheres; by contrast, in the EA-N group.

Results

The difference in neurological deficit scores between the first and fourth days and the difference in Rotarod test time between the fourth and first days after reperfusion were greater in the EA-P and EA-N groups than in the sham group (all p < 0.001). In the lesioned hemisphere, neuronal nuclei (NeuN), γ-aminobutyric acid-A (GABA)-A, postsynaptic density 95 (PSD95), and astrocyte glutamate transporter 1 (GLT-1) expression and microtubule-associated protein 2 (MAP2)/glyceraldehyde 3-phosphate dehydrogenase (GADPH) ratios were greater and the glial fibrillary acid protein (GFAP)/GADPH ratios were smaller in the EA-P than in the sham group (all p < 0.05), but these ratios in the EA-N group were similar to those in the sham group (all p > 0.05); serum adrenaline and serotonin levels in the sham group were lower than those in the normal and EA-P groups (both p < 0.05), and cerebrospinal fluid (CSF) glutamate levels were higher in the EA-P group than in the sham group (p < 0.05).

Conclusion

EA improved neurological function through multiple pathways. However, placing the anode on the lesioned hemisphere can provide more neuroprotection.

Intercellular mitochondrial transfer in the brain, a new perspective for targeted treatment of central nervous system diseases

AIM

Mitochondria is one of the important organelles involved in cell energy metabolism and regulation and also play a key regulatory role in abnormal cell processes such as cell stress, cell damage, and cell canceration. Recent studies have shown that mitochondria can be transferred between cells in different ways and participate in the occurrence and development of many central nervous system diseases. We aim to review the mechanism of mitochondrial transfer in the progress of central nervous system diseases and the possibility of targeted therapy.

METHODS

The PubMed databank, the China National Knowledge Infrastructure databank, and Wanfang Data were searched to identify the experiments of intracellular mitochondrial transferrin central nervous system. The focus is on the donors, receptors, transfer pathways, and targeted drugs of mitochondrial transfer.

RESULTS

In the central nervous system, neurons, glial cells, immune cells, and tumor cells can transfer mitochondria to each other. Meanwhile, there are many types of mitochondrial transfer, including tunneling nanotubes, extracellular vesicles, receptor cell endocytosis, gap junction channels, and intercellular contact. A variety of stress signals, such as the release of damaged mitochondria, mitochondrial DNA, or other mitochondrial products and the elevation of reactive oxygen species, can trigger the transfer of mitochondria from donor cells to recipient cells. Concurrently, a variety of molecular pathways and related inhibitors can affect mitochondrial intercellular transfer.

CONCLUSION

This study reviews the phenomenon of intercellular mitochondrial transfer in the central nervous system and summarizes the corresponding transfer pathways. Finally, we propose targeted pathways and treatment methods that may be used to regulate mitochondrial transfer for the treatment of related diseases.

Treatment of stroke in aged male and female rats with Vepoloxamer and tPA reduces neurovascular damage

Stroke is a leading cause of death and disability worldwide, mainly affecting the elderly. Unfortunately, current treatments for acute ischemic stroke warrant improvement. To date, tissue plasminogen activator (tPA) is of limited use in stroke patients mainly due to its narrow therapeutic window and potential for hemorrhagic complication. The adjuvant treatment with Vepoloxamer, a purified amphipathic polymer has been shown to enhance the thrombolytic efficacy of tPA treatment in young adult male rats after embolic stroke. However, most stroke patients are aged; therefore, the current study investigated the therapeutic effect of the combined tPA and Vepoloxamer treatment in aged male and female rats subjected to embolic stroke.

Methods

Male and female Wistar rats at 18 months of age were subjected to embolic middle cerebral artery occlusion and treated either with monotherapy of tPA or Vepoloxamer, a combination of these two agents, or saline at 4 h after stroke onset. Neurological outcomes were evaluated with a battery of behavioral tests including adhesive removal, foot-fault, and modified neurological severity score tests at 1 and 7 days after stroke onset, followed by histopathological analysis of infarct volume. Residual clot size and vascular patency and integrity were analyzed.

Results

The combination treatment with Vepoloxamer and tPA significantly reduced infarct volume and neurological deficits in male and female rats compared to rats treated with saline and the monotherapies of tPA and Vepoloxamer. While Vepoloxamer monotherapy moderately reduced neurological deficits, monotherapies with tPA and Vepoloxamer failed to reduce infarct volume compared to saline treatment. Furthermore, the combination treatment with tPA and Vepoloxamer accelerated thrombolysis, reduced ischemia and tPA-potentiated microvascular disruption, and concomitantly improved cerebrovascular integrity and perfusion in the male ischemic rats.

Conclusion

Combination treatment with tPA and Vepoloxamer at 4 h after stroke onset effectively reduces ischemic neurovascular damage by accelerating thrombolysis and reducing ischemia and tPA potentiated side effects in the aged rats. This funding suggests that the combination treatment with tPA and Vepoloxamer represents a promising strategy to potentially apply to the general population of stroke patients.

Exosome-shuttled MYCBPAP from bone marrow mesenchymal stem cells regulates synaptic remodeling and ameliorates ischemic stroke in rats

BACKGROUND AND PURPOSE

Mesenchymal stem cells (MSC) have been demonstrated to improve cardiac function via the secretion of paracrine factors rather than direct differentiation. We, therefore, investigated whether bone marrow-derived MSC (BMSC)-released exosomes (BMSC-exo) enhance neurological recovery in spontaneously hypertensive rats (SHR) with ischemic stroke.

METHODS

Markers of BMSC and BMSC-exo were detected to characterize BMSC and BMSC-exo. A green fluorescent PKH-67-labeled assay was conducted to ensure BMSC-exo internalization. Rat neuronal cells (RNC) were induced with Ang II and oxygen-glucose deprivation. The protective effects of BMSC-exo on RNC were studied by CCK-8, LDH, and immunofluorescence assays. SHR were subjected to middle cerebral artery occlusion, and the systolic and diastolic blood pressure changes in the modeled rats were measured. The effects of BMSC-exo on SHR were investigated by mNSS scoring, foot-fault tests, immunohistochemistry, Western blot, TTC staining, TUNEL, and HE staining. The hub genes related to SHR and proteins shuttled by BMSC-exo were intersected to obtain a possible candidate, followed by rescue experiments.

RESULTS

BMSC-exo significantly promoted RNC viability and repressed cell apoptosis and cytotoxicity. Moreover, SHR administrated with BMSC-exo exhibited significant improvement in functional recovery and narrowed infarct size. BMSC-exo shuttled the MYCBPAP protein. Knockdown of MYCBPAP inhibited the protective effects of BMSC-exo on RNC and exacerbated synaptic damage in SHR.

CONCLUSIONS

MYCBPAP shuttled by BMSC-exo facilitates synaptic remodeling in SHR, which may contribute to a therapeutic strategy for ischemic stroke treatment.

Cleavage of semaphorin 4 C interferes with the neuroprotective effect of the semaphorin 4 C/Plexin B2 pathway on experimental intracerebral hemorrhage in rats

Semaphorin 4 C (SEMA4C) and its cognate receptor Plexin B2 are important regulators of axon guidance and are involved in many neurological diseases, in which SEMA4C acts not only as a ligand ("forward" mode) but also as a signaling receptor ("reverse" mode). However, the role of SEMA4C/Plexin B2 in intracerebral hemorrhage (ICH) remains unclear. In this study, ICH in adult male Sprague-Dawley rats was induced by autologous blood injection in the right basal ganglia. In vitro, cultured primary neurons were subjected to OxyHb to imitate ICH injury. Recombinant SEMA4C (rSEMA4C) and overexpressing lentiviruses encoding full-length SEMA4C or secretory SEMA4C (sSEMA4C) were administered to rats by intraventricular injection. First, we found that elevated levels of sSEMA4C in the cerebrospinal fluid (CSF) of clinical patients were associated with poor prognosis. Both SEMA4C and sSEMA4C were increased in brain tissue around the hematoma after ICH in rats. Overexpression of SEMA4C attenuated neuronal apoptosis, neurosis, and neurologic impairment after ICH. However, treatment with rSEMA4C or sSEMA4C overexpression exacerbated neuronal injury. In addition, when treated with SEMA4C overexpression, the forward mode downstream protein RhoA and the reverse mode downstream ID1/3 transcriptional factors of SEMA4C/Plexin B2 signaling were all activated. Nevertheless, when exposed to rSEMA4C or sSEMA4C overexpression, only the forward mode was activated. Thus, sSEMA4C may be a novel molecular biomarker to predict the prognosis of patients with ICH, and the prevention of SEMA4C cleavage is expected to be a promising therapeutic target.

Blood Compatibility of Drug-Inorganic Hybrid in Human Blood: Red Blood Cell Hitchhiking and Soft Protein Corona

A drug-delivery system consisting of an inorganic host-layered double hydroxide (LDH)-and an anticancer drug-methotrexate (MTX)-was prepared via the intercalation route (MTX-LDH), and its hematocompatibility was investigated. Hemolysis, a red blood cell counting assay, and optical microscopy revealed that the MTX-LDH had no harmful toxic effect on blood cells. Both scanning electron microscopy and atomic force microscopy exhibited that the MTX-LDH particles softly landed on the concave part inred blood cells without serious morphological changes of the cells. The time-dependent change in the surface charge and hydrodynamic radius of MTX-LDH in the plasma condition demonstrated that the proteins can be gently adsorbed on the MTX-LDH particles, possibly through protein corona, giving rise to good colloidal stability. The fluorescence quenching assay was carried out to monitor the interaction between MTX-LDH and plasma protein, and the result showed that the MTX-LDH had less dynamic interaction with protein compared with MTX alone, due to the capsule moiety of the LDH host. It was verified by a quartz crystal microbalance assay that the surface interaction between MTX-LDH and protein was reversible and reproducible, and the type of protein corona was a soft one, having flexibility toward the biological environment.

PPM1K mediates metabolic disorder of branched-chain amino acid and regulates cerebral ischemia-reperfusion injury by activating ferroptosis in neurons

Ischemic stroke is a neurological disorder caused by vascular stenosis or occlusion, accounting for approximately 87% of strokes. Clinically, the most effective therapy for ischemic stroke is vascular recanalization, which aims to rescue neurons undergoing ischemic insults. Although reperfusion therapy is the most effective treatment for ischemic stroke, it still has limited benefits for many patients, and ischemia-reperfusion (I/R) injury is a widely recognized cause of poor prognosis. Here, we aim to investigate the mechanism of protein phosphatase Mg2+/Mn2+ dependent 1 K (PPM1K) mediates metabolic disorder of branched-chain amino acids (BCAA) by promoting fatty acid oxidation led to ferroptosis after cerebral I/R injury. We established the I/R model in mice and used BT2, a highly specific BCAA dehydrogenase (BCKD) kinase inhibitor to promote BCAA metabolism. It was further verified by lentivirus knocking down PPM1K in neurons. We found that BCAA levels were elevated after I/R injury due to dysfunctional oxidative degradation caused by phosphorylated BCKD E1α subunit (BCKDHA). Additionally, the level of phosphorylated BCKDHA was determined by decreased PPM1K in neurons. We next demonstrated that BCAA could induce oxidative stress, lipid peroxidation, and ferroptosis in primary cultured cortical neurons in vitro. Our results further showed that BT2 could reduce neuronal ferroptosis by enhancing BCAA oxidation through inhibition of BCKDHA phosphorylation. We further found that defective BCAA catabolism could induce neuronal ferroptosis by PPM1K knockdown. Furthermore, BT2 was found to alleviate neurological behavior disorders after I/R injury in mice, and the effect was similar to ferroptosis inhibitor ferrostatin-1. Our findings reveal a novel role of BCAA in neuronal ferroptosis after cerebral ischemia and provide a new potential target for the treatment of ischemic stroke.

FNDC5 inhibits autophagy of bone marrow mesenchymal stem cells and promotes their survival after transplantation by downregulating Sp1

Regenerative therapy based on mesenchymal stem cells (MSCs) has great promise to achieve functional recovery in cerebral infarction patients. However, the survival rate of transplanted MSCs is extremely low because of destructive autophagy caused by the harsh ischemic microenvironment in cerebral infarct tissue. The mechanism by which fibronectin type III domain protein 5 (FNDC5) regulates autophagy of transplanted bone marrow-MSCs (BMSCs) following ischemic injury needs to be elucidated. In this study, we confirmed that FNDC5 promotes the survival of transplanted BMSCs in a rat cerebral infarction model. Furthermore, bioinformatic analysis and verification experiments revealed the transcription factor, Sp1, to be a key mediator of autophagy regulation by FNDC5. FNDC5 significantly inhibited BMSC autophagy by down-regulating Sp1 and the autophagy-related Sp1-target gene, ULK2. Transplanted BMSCs overexpressing FNDC5 (BMSCs-OE-FNDC5) promoted neurovascular proliferation and alleviated ischemic brain injury in cerebral infarct model rats. However, the increased survival and enhanced neuroprotective effect of transplanted BMSCs-OE-FNDC5 were reversed by simultaneous overexpression of Sp1. Our data indicate a role for FNDC5 in BMSC survival and reveal a novel mechanism of transcription regulation through Sp1 for the autophagy-related gene ULK2. Modulation of FNDC5 may promote survival capacity and improve the therapeutic effect of BMSCs in various tissues following ischemia.

Bacteria-Derived Outer-Membrane Vesicles Hitchhike Neutrophils to Enhance Ischemic Stroke Therapy

The treatment of reperfusion injury after ischemic stroke remains unsatisfactory since the blood-brain barrier (BBB) prevents most neuroprotective agents from entering the brain. Here, a strategy is proposed based on bacteria-derived outer-membrane vesicle (OMV) hitchhiking on the neutrophils for enhanced brain delivery of pioglitazone (PGZ) to treat ischemic stroke. By encapsulating PGZ into OMV, the resulting OMV@PGZ nanoparticles inherit the functions associated with the bacterial outer membrane, making them ideal decoys for neutrophil uptake. The results show that OMV@PGZ simultaneously inhibits the activation of nucleotide oligomerization-like receptor protein 3 (NLRP3) inflammasomes and ferroptosis and reduces the reperfusion injury to exert a neuroprotective effect. Notably, the transcription factors Pou2f1 and Nrf1 of oligodendrocytes are identified for the first time to be involved in this process and promoted neural repair by single-nucleus RNA sequencing (snRNA-seq).

CCA repair or ECA ligation-Which middle cerebral artery occlusion is better in the reperfusion mouse model?

A reliable animal model is essential for ischemic stroke research. The implications of the external carotid artery (ECA) transection or common carotid artery (CCA) ligation have been described. Thus, a modified animal model, the CCA-repair model, has been established, and studies have shown that the CCA-repair model has potential advantages over the CCA-ligation model. However, whether the CCA-repair model is superior to the ECA-ligation model remains unclear. Sixty male C57BL/6 mice were randomly assigned to establish the CCA-repair (n = 34) or ECA-ligation (n = 26) models. Cerebral blood flow before middle cerebral artery occlusion (MCAO), immediately after MCAO and reperfusion were monitored and the operation duration, postoperative body weight, and food intake within 7 days, and the number of intraoperative and postoperative deaths within 7 days were recorded in the two models. Modified neurological severity scores and Bederson (0-5) scores were used to evaluate postoperative neurological function deficits on Days 1/3/5/7. 2,3,5-Triphenyltetrazolium chloride staining was used to quantify lesion volume on Day 7 after the operation. We found the establishment of the CCA-repair model required a longer total operation duration (p = 0.0175), especially the operation duration of reperfusion (p < 0.0001). However, there was no significant difference in body weight and food intake development, lesion volume and intragroup variability, neurological function deficits, mortality, and survival probability between the two groups. The CCA-repair model has no significant advantage over the ECA-ligation model. The ECA-ligation model is still a better choice for focal cerebral ischemia.

Homocysteine impedes neurite outgrowth recovery after intracerebral haemorrhage by downregulating pCAMK2A

Hyperhomocysteinemia (HHcy) is independently associated with poorer long-term prognosis in patients with intracerebral haemorrhage (ICH); however, the effect and mechanisms of HHcy on ICH are still unclear. Here, we evaluated neurite outgrowth and neurological functional recovery using simulated models of ICH with HHcy in vitro and in vivo. We found that the neurite outgrowth velocity and motor functional recovery in the ICH plus HHcy group were significantly slower than that in the control group, indicating that homocysteine (Hcy) significantly impedes the neurite outgrowth recovery after ICH. Furthermore, phosphoproteomic data and signalome analysis of perihematomal brain tissues suggested that calmodulin-dependent protein kinases 2 (CAMK2A) kinase substrate pairs were significantly downregulated in ICH with HHcy compared with autologous blood injection only, both western blot and immunofluorescence staining confirmed this finding. Additionally, upregulation of pCAMK2A significantly increased neurite outgrowth recovery in ICH with HHcy. Collectively, we clarify the mechanism of HHcy-hindered neurite outgrowth recovery, and pCAMK2A may serve as a therapeutic strategy for promoting neurological recovery after ICH.

Connexin 43 Promotes Neurogenesis via Regulating Aquaporin-4 after Cerebral Ischemia

We aimed to test the effects of connexin43 (Cx43) on ischemic neurogenesis and examined whether it was dependent on aquaporin-4 (AQP4). We detected the expression of Cx43 and AQP4 in the ipsilateral subventricular zone (SVZ) and peri-infarct cortex after middle cerebral artery occlusion (MCAO). Also, we examined neurogenesis in the above regions via co-labeling of 5-bromo-2-deoxyuridine (BrdU)/neuronal nuclear antigen (NeuN) and BrdU/doublecortin (DCX). The effects of Cx43 and AQP4 were investigated by using two transgenic animals: heterozygous Cx43 (Cx43±) mice and AQP4 knockout (AQP4-/-) mice, and connexin mimetic peptide (CMP), a selective Cx43 blocker. We demonstrated AQP4 and Cx43 were co-expressed in the astrocytes after MCAO and the expression was highly increased in ipsilateral SVZ and peri-infarct cortex. Cx43± mice had larger infarction volumes and worse neurological function. Both BrdU/NeuN and BrdU/DCX co-labeled cells in the two regions were reduced in Cx43± and AQP4-/- mice compared to wild-type (WT) mice, suggesting Cx43 and AQP4 participated in neurogenesis of neural stem cells. Moreover, CMP decreased AQP4 expression and inhibited neurogenesis in WT mice, while the latter failed to be observed in AQP4-/- mice. Besides, higher levels of IL-1β and TNF-α were detected in the SVZ and peri-infarct cortex of AQP4-/- and Cx43± mice than those in WT mice. In conclusion, our data suggest that Cx43 elicits neuroprotective effects after cerebral ischemia through promoting neurogenesis in the SVZ to regenerate the injured neurons, which is AQP4 dependent and associated with down-regulation of inflammatory cytokines IL-1β and TNF-α.

Neuroprotective Effects of Tryptanthrin-6-Oxime in a Rat Model of Transient Focal Cerebral Ischemia

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35-49 and 46-67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28-31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood-brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

Ultraflexible endovascular probes for brain recording through micrometer-scale vasculature

Implantable neuroelectronic interfaces have enabled advances in both fundamental research and treatment of neurological diseases but traditional intracranial depth electrodes require invasive surgery to place and can disrupt neural networks during implantation. We developed an ultrasmall and flexible endovascular neural probe that can be implanted into sub-100-micrometer-scale blood vessels in the brains of rodents without damaging the brain or vasculature. In vivo electrophysiology recording of local field potentials and single-unit spikes have been selectively achieved in the cortex and olfactory bulb. Histology analysis of the tissue interface showed minimal immune response and long-term stability. This platform technology can be readily extended as both research tools and medical devices for the detection and intervention of neurological diseases.

Bilateral transcranial direct-current stimulation promotes migration of subventricular zone-derived neuroblasts toward ischemic brain

Ischemic insult stimulates proliferation of neural stem cells (NSCs) in the subventricular zone (SVZ) after stroke. However, only a fraction of NSC-derived neuroblasts from SVZ migrate toward poststroke brain region. We have previously reported that direct-current stimulation guides NSC migration toward the cathode in vitro. Accordingly, we set up a new method of transcranial direct-current stimulation (tDCS), in which the cathodal electrode is placed on the ischemic hemisphere and anodal electrode on the contralateral hemisphere of rats subjected to ischemia-reperfusion injury. We show that the application of this bilateral tDCS (BtDCS) promotes the migration of NSC-derived neuroblasts from SVZ toward the cathode direction into poststroke striatum. Reversing the position of the electrodes blocks the effect of BtDCS on the migration of neuroblasts from SVZ. BtDCS protects against neuronal death and improves the functional recovery of stroke animals. Thus, the migration of NSC-derived neuroblasts from SVZ toward poststroke brain region contributes to the effect of BtDCS against ischemia-induced neuronal death, supporting a potential development of noninvasive BtDCS as an endogenous neurogenesis-based stroke therapy.

Enhanced brain delivery of hypoxia-sensitive liposomes by hydroxyurea for rescue therapy of hyperacute ischemic stroke

Ischemic stroke is characterized by high morbidity, disability, and mortality. Unfortunately, the only FDA-approved pharmacological thrombolytic, alteplase, has a narrow therapeutic window of only 4.5 h. Other drugs like neuroprotective agents have not been clinically used because of their low efficacy. To improve the efficacy of neuroprotective agents and the effectiveness of rescue therapies for hyperacute ischemic stroke, we investigated and verified the variation trends of the blood-brain barrier (BBB) permeability and regional cerebral blood flow over 24 h in rats that had ischemic strokes. Hypoperfusion and the biphasic increase of BBB permeability are still the main limiting factors for lesion-specific drug distribution and drug brain penetration. Herein, the nitric oxide donor hydroxyurea (HYD) was reported to downregulate the expression of tight junction proteins and upregulate intracellular nitric oxide content in the brain microvascular endothelial cells subjected to oxygen-glucose deprivation, which was shown to facilitate the transport of liposomes across  brain endothelial monolayer in an in vitro model. HYD also increased the BBB permeability and promoted microcirculation in the hyperacute phase of stroke. The neutrophil-like cell-membrane-fusogenic hypoxia-sensitive liposomes exhibited excellent performance in targeting the inflamed brain microvascular endothelial cells, enhancing cell association, and promoting rapid hypoxic-responsive release in the hypoxic microenvironment. Overall, the combined HYD and hypoxia-sensitive liposome dosing regimen effectively decreased the cerebral infarction volume and relieved neurological dysfunction in rats that had ischemic strokes; these therapies were involved in the anti-oxidative stress effect and the neurotrophic effect mediated by macrophage migration inhibitory factor.

Loureirin B protects against cerebral ischemia/reperfusion injury through modulating M1/M2 microglial polarization via STAT6 / NF-kappaB signaling pathway

The latest research indicates that modulating microglial polarization from M1 to M2 phenotype may be a coping therapy for ischemic stroke. The present study thereby evaluated the effects of loureirin B (LB), a monomer compound extracted from Sanguis Draconis flavones (SDF), on cerebral ischemic injury and the potential mechanisms. The middle cerebral artery occlusion (MCAO) model was established in male Sprague-Dawley rats to induce cerebral ischemia/reperfusion (I/R) injury in vivo, and BV2 cells were exposed to oxygen-glucose deprivation and reintroduction (OGD/R) to mimic cerebral I/R injury in vitro. The results showed that LB significantly reduced infarct volume, neurological deficits and neurobehavioral deficits, apparently improved histopathological changes and neuronal loss in cortex and hippocampus of MCAO/R rats, markedly decreased the proportion of M1 microglia cells and the level of pro-inflammatory cytokines, and increased the proportion of M2 microglia and the level of anti-inflammatory cytokines both in vivo and in vitro. In addition, LB evidently improved the p-STAT6 expression and reduced the NF-κB (p-p65) expression after cerebral I/R injury in vivo and in vitro. IL-4 (a STAT6 agonist) exhibited a similar impact to that of LB, while AS1517499 (a STAT6 inhibitor) significantly reversed the effect of LB on BV-2 cells after OGD/R. These findings point to the protection of LB against cerebral I/R injury by modulating M1/M2 polarization of microglia via the STAT6/NF-κB signaling pathway, hence LB may be a viable treatment option for ischemic stroke.

Bone Marrow Mesenchymal Stem Cells-derived Exosomal Long Non-coding RNA KLF3 antisense RNA 1 Enhances Autophagy to Protect Against Cerebral Ischemia/Reperfusion Injury Via ETS Variant Transcription Factor 4/Silent Information Regulator 1 Axis

Mesenchymal stem cells (MSCs)-derived exosomes are demonstrated to exert neuroprotective effects in stroke. We aimed to explore the role and mechanism of long non-coding RNA (lncRNA) KLF3 antisense RNA 1 (KLF3-AS1) in bone marrow mesenchymal stem cells-derived exosomes (BMSCs-Exos) in cerebral ischemia/reperfusion (I/R) injury. Exosomes were isolated from the culture medium of BMSCs. A mouse model of middle cerebral artery occlusion (MCAO) in vivo and a BV-2 cell model of oxygen and glucose deprivation/reoxygenation (OGD/RX) in vitro were established. Cell viability and apoptosis were detected using MTT assay, TUNEL staining and flow cytometry, respectively. Related proteins were determined with western blot and immunohistochemistry, while related RNAs were analyzed by RT-qPCR. Neurological deficit and cerebral infarct volume were evaluated by the modified neurological severity score (mNSS) and TTC staining, respectively. Our observations indicate that exosomes derived from BMSCs-preconditioned medium exerted neuroprotective effects, as indicated by the increased cell viability and the suppressed apoptosis in OGD/RX-suffered BV-2 cells. KLF3-AS1 expression was upregulated in BMSCs-Exos. Furthermore, KLF3-AS1 knockdown antagonized the protective effects of BMSCs-Exos. Mechanistically, BMSCs-Exos carrying KLF3-AS1 inhibited apoptosis via enhancing autophagy. KLF3-AS1 was found to recruit ETS variant transcription factor 4 (ETV4), which upregulated Sirt1 expression. Knockdown of KLF3-AS1 neutralized the protective effects of BMSCs-Exos on MCAO-induced brain injury, which was then reversed by the treatment with Sirt1 inhibitor EX527. We concluded that KLF3-AS1 derived from BMSCs-Exos promoted autophagy to alleviate I/R injury via ETV4/Sirt1 axis.

Mesenchymal stem cells- an excellent therapeutic agent for cancer

Despite rapid advancement in research of diagnostics and therapeutics, cancer is the most dangerous disease-causing millions of deaths worldwide. Many of the conventional anticancer therapies can even lead to developing resistance to therapy and recurrence of cancer. To find a new, alternative treatment strategy for a variety of ailments scientists and researchers have turned their attention to cell therapies and regenerative medicine. Stem cells are now being researched for their extensive potential application in therapy for several incurable illnesses including cancer. One of the most often employed cell types for regenerative medicine is mesenchymal stem cells. Mesenchymal stem cells (MSCs) are considered a promising source of stem cells in personalized cell-based therapies. The inherent tumor tropic and immune-modulatory properties of MSCs can be used to target cancer cells. This review aims to focus on the anticancer properties of MSCs and their effect on different signaling pathways. Later on, we discuss the advantages of engineered MSCs over non-engineered MSCsin cancer therapy.

Fucoidan (A sulfated polysaccharide) and Cerebroprotein in combination alleviate the neuroinflammation-mediated neural damage and functional deficits in the focal cerebral ischemia model of rat

Cerebral ischemic reperfusion injury could emanate a cascade of events ensuing in neural death and severe neurobehavioural deficits. The currently available interventions have failed to target the multimodal, interlinked mechanisms that operate cerebral ischemia-induced damage and functional loss. So an integrative intervention has become a mandate to overcome the deleterious mechanisms involved in cerebral ischemic pathophysiology. In this study, adult male Sprague dawley rats were exposed to 2 hours of right middle cerebral artery occlusion (rMCAo) followed by reperfusion, and the intervention group received Fucoidan alone at a dose of 50mg/kg, i.p (intraperitoneal), Cerebrolysin alone at a dose of 2.5mg/kg body weight and the combination of both. The sham rats were exposed to surgical procedures, except for the rMCAo. The assessments of the groups were made 24 hours after the rMCAo. The stand-alone treatment with Fucoidan, Cerebrolysin has shown a better outcome in the neurobehavioral and, histopathological assessments and the combination has made a significant reduction in the neurological deficits and the infarct volume when compared to the standalone groups. The BBB integrity was well preserved in the combination group when compared with the lesion and standalone groups. Moreover, the combined intervention reduced the level of pro-inflammatory cytokines TNFα, NFkB, IL1α, IL1-β, IL-6, CD68, COX-2, and mRNA expression of inflammatory genes IL1α, IL1-β, IL-6, IBA-1, and COX-2 effectively. In conclusion, the present study suggests that rMCAo induced neuroinflammation and neurobehavioural alterations were attenuated by intervention with a combination of Fucoidan and cerebrolysin; Further, Fucoidan and Cerebrolysin combination improved the ischemic tolerance level by promoting the proteins and genes that regulate the inflammatory cytokines and in aiding better recovery after ischemic reperfusion injury.

Sirt1 Overexpression Inhibits Fibrous Scar Formation and Improves Functional Recovery After Cerebral Ischemic Injury Through the Deacetylation of 14-3-3ζ

Cerebral ischemic stroke is one of the leading causes of human death. The fibrous scar is one of major factors influencing repair in central nervous system (CNS) injury. Silencing information regulator 2-related enzyme 1 (Sirt1) can regulate peripheral tissue and organ fibrosis. However, it is unclear how the fibrous scar forms and is regulated and it is unknown whether and how Sirt1 regulates the formation of the fibrous scar after cerebral ischemic stroke. Therefore, in the present study, we examined the effects of Sirt1 on the formation of the fibrotic scar after middle cerebral artery occlusion/reperfusion (MCAO/R) injury in vivo and on the transforming growth factor β1 (TGF-β1)-induced meningeal fibroblast fibrotic response in vitro, and we explored the molecular mechanisms underlying the Sirt1-regulated fibrosis process in vitro. We found that MCAO/R injury induced fibrotic scar formation in the ischemic area, which was accompanied by the downregulation of Sirt1 expression. The overexpression of Sirt1 reduced the infarct volume, improved Nissl body structure and reduced neurons injury, attenuated formation of fibrotic scar, upregulated growth associated protein43 (GAP43) and synaptophysin (SYP) expression, and promoted neurological function recovery. Similarly, Sirt1 expression was also downregulated in the TGF-β1-induced fibrosis model. Sirt1 overexpression inhibited fibroblast migration, proliferation, transdifferentiation into myofibroblasts, and secretion of extracellular matrix(ECM) by regulating the deacetylation of lysine at K49 and K120 sites of 14-3-3ζ in vitro. Therefore, we believe that Sirt1 could regulate fibrous scar formation and improve neurological function after cerebral ischemic stroke through regulating deacetylation of 14-3-3ζ.

Downregulation of Histone H4 Lysine 16 Acetylation Ameliorates Autophagic Flux by Resuming Lysosomal Functions in Ischemic Neurons

Autophagic/lysosomal dysfunction was a critical pathogenesis of neuronal death after an ischemic stroke, but what drove the impairment of autophagic flux remained elusive. Studies indicated that histone H4 lysine 16 acetylation (H4K16ac) drastically modulated the autophagic/lysosomal signaling pathway. Herein, we investigated whether the autophagic/lysosomal dysfunction in neurons could be restored by altering H4K16ac levels after cerebral ischemia. The rat model of ischemic stroke and the cell ischemia model in HT22 neurons were prepared by middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD), respectively. The result showed that H4K16ac could be effectively reduced by intracerebroventricular administration with MG149 (a H4K16ac inhibitor) after an ischemic stroke. Moreover, attenuated H4K16ac greatly alleviated the autophagic/lysosomal dysfunction in penumbral neurons, as indicated by decreased autophagic substrates of LC3-II, insoluble SQSTM1, and ubiquitinated proteins, accompanied by increased lysosomal cathepsin D. Conversely, treatment with trichostatin A (TSA, a H4K16ac facilitator) aggravated the impairment of autophagic flux. This regulative machinery of H4K16ac on the autophagic/lysosomal signaling pathway was also manifested in the OGD model of HT22 neurons. Furthermore, H4K16ac attenuation-ameliorated autophagic flux significantly alleviated stroke brain injury, as reflected by decreased infarct size, neuron loss, and neurological deficits. Similarly, the H4K16ac inhibition-mitigated autophagic/lysosomal dysfunction markedly promoted neuron survival and cell viability in OGD HT22 neurons. However, H4K16ac downregulation-ameliorated autophagic flux in neurons and thereby induced neuroprotection could be greatly counteracted by the lysosomal inhibitor bafilomycin A1 (Baf-A1). Our data indicate that cerebral ischemia-elevated H4K16ac creates the autophagic/lysosomal dysfunction due to lysosomal inefficiency, suggesting that H4K16ac attenuation benefits poststroke neuroprotection by resuming lysosomal functions in neurons.

Transmission of NLRP3-IL-1β Signals in Cerebral Ischemia and Reperfusion Injury: from Microglia to Adjacent Neuron and Endothelial Cells via IL-1β/IL-1R1/TRAF6

The pyrin domain-containing protein 3 (NLRP3) inflammasome drives the profound cerebral ischemia and reperfusion injury (I/R) and mediates the secretion of IL-1β (interleukin-1β), which exerts a subsequent cascade of inflammatory injury. The NLRP3-activated-microglial manipulation in adjacent neuronal and endothelial NLRP3 activation has been confirmed in our previous studies. In the present study, we extended the cognition of how microglia mediated neuronal and endothelial NLRP3-IL-1β signaling during cerebral ischemia and reperfusion injury. In vitro, Neuro-2a and bEND3 cells were cultured alone or co-cultured with BV2 cells and oxygen-glucose deprivation/reoxygenation (OGD/R) was performed. In vivo, transient middle cerebral artery occlusion (tMCAO) rat models and lentiviral silencing targeting IL-1R1 were performed. The NLRP3 inflammasome activation was evaluated by enzyme-linked immunosorbent assay, western blotting, immunoprecipitation, immunohistochemistry, and immunofluorescence. In the co-culture system after OGD/R treatment, NLRP3 inflammasomes in neurons and endothelial cells were activated by microglial IL-1β via IL-1β/IL-1R1/TRAF6 signaling pathway, with the basal protein level of NLRP3. In addition, ruptured lysosomes engulfing ASC specks which were possibly secreted from microglia triggered the enhanced NLRP3 expression. In cortices of tMCAO rats at 24 h of reperfusion, silencing IL-1R1, mainly presented in neurons and endothelial cells, was efficient to block the subsequent inflammatory damage and leukocyte brain infiltration, leading to better neurological outcome. Neuronal and endothelial NLRP3 inflammasomes were activated by microglia in cerebral ischemia and reperfusion injury mainly via IL-1β/IL-1R1/TRAF6 signaling, which might be therapeutically targetable.

Exogenous interleukin 33 enhances the brain's lymphatic drainage and toxic protein clearance in acute traumatic brain injury mice

The persistent dysregulation and accumulation of poisonous proteins from destructive neural tissues and cells activate pathological mechanisms after traumatic brain injury (TBI). The lymphatic drainage system of the brain, composed of the glymphatic system and meningeal lymphatic vessels (MLVs), plays an essential role in the clearance of toxic waste after brain injury. The neuroprotective effect of interleukin 33 (IL-33) in TBI mice has been demonstrated; however, its impact on brain lymphatic drainage is unclear. Here, we established a fluid percussion injury model to examine the IL-33 administration effects on neurological function and lymphatic drainage in the acute brain of TBI mice. We verified that exogenous IL-33 could improve the motor and memory skills of TBI mice and demonstrated that in the acute phase, it increased the exchange of cerebrospinal and interstitial fluid, reversed the dysregulation and depolarization of aquaporin-4 in the cortex and hippocampus, improved the drainage of MLVs to deep cervical lymph nodes, and reduced tau accumulation and glial activation. We speculate that the protective effect of exogenous IL-33 on TBI mice's motor and cognitive functions is related to the enhancement of brain lymphatic drainage and toxic metabolite clearance from the cortex and hippocampus in the acute stage. These data further support the notion that IL-33 therapy may be an effective treatment strategy for alleviating acute brain injury after TBI.

Transcranial direct current stimulation alleviated ischemic stroke induced injury involving the BDNF-TrkB signaling axis in rats

Ischemic stroke causes a complicated sequence of apoptotic cascades leading to neuronal damage and functional impairments. Transcranial direct current stimulation (tDCS) is a non-invasive treatment technique that uses electrodes to deliver weak current to the head. It could influence brain activity and has a crucial role in neuronal survival and plasticity. The current study investigated the neuroprotective effects and potential mechanisms of tDCS by brain-derived neurotrophic factor (BDNF) and its related receptor tropomyosin-receptor kinase B (TrkB) against apoptosis following ischemic injury in vivo. The effect of consecutive treatment with tDCS for seven days on rats after Middle cerebral artery occlusion/reperfusion (MCAO/R) surgery was studied. Western blotting, immunofluorescent staining, TUNEL assay, and electron microscope were conducted seven days after tDCS treatment, and the motor function was assessed at 1, 3, and 7 days. Activities of BDNF-TrkB signaling axis and apoptosis-related proteins were determined in the cerebral cortex. At seven days after tDCS treatment, it increased BDNF levels and promoted the regeneration of axons compared with the MCAO/R group. There was also a reduction in neuronal apoptosis and improved functional deficits. Whereafter, a TrkB receptor inhibitor K252a was administrated to clarify whether the neuroprotection of tDCS is exerted via BDNF-TrkB signaling. The results depicted that K252a application significantly inhibited the neuroprotection impact of tDCS treatment. It was accompanied by a significant downregulation of phosphorylation of TrkB, PI3K, and Akt. Our study investigated the neuroprotective effects of tDCS against ischemic injury. The results indicate that upregulation of BDNF and its critical receptor TrkB, as well as its downstream PI3K/Akt pathway, were involved in the protective effects exerted by tDCS.

Synaptotagmin-3 interactions with GluA2 mediate brain damage and impair functional recovery in stroke

Synaptotagmin III (Syt3) is a Ca2+-dependent membrane-traffic protein that is highly concentrated in synaptic plasma membranes and affects synaptic plasticity by regulating post-synaptic receptor endocytosis. Here, we show that Syt3 is upregulated in the penumbra after ischemia/reperfusion (I/R) injury. Knockdown of Syt3 protects against I/R injury, promotes recovery of motor function, and inhibits cognitive decline. Overexpression of Syt3 exerts the opposite effects. Mechanistically, I/R injury augments Syt3-GluA2 interactions, decreases GluA2 surface expression, and promotes the formation of Ca2+-permeable AMPA receptors (CP-AMPARs). Using a CP-AMPAR antagonist or dissociating the Syt3-GluA2 complex via TAT-GluA2-3Y peptide promotes recovery from neurological impairments and improves cognitive function. Furthermore, Syt3 knockout mice are resistant to cerebral ischemia because they show high-level expression of surface GluA2 and low-level expression of CP-AMPARs after I/R. Our results indicate that Syt3-GluA2 interactions, which regulate the formation of CP-AMPARs, may be a therapeutic target for ischemic insults.

Ultra-flexible endovascular probes for brain recording through micron-scale vasculature

Implantable neuroelectronic interfaces have enabled significant advances in both fundamental research and treatment of neurological diseases, yet traditional intracranial depth electrodes require invasive surgery to place and can disrupt the neural networks during implantation. To address these limitations, we have developed an ultra-small and flexible endovascular neural probe that can be implanted into small 100-micron scale blood vessels in the brains of rodents without damaging the brain or vasculature. The structure and mechanical properties of the flexible probes were designed to meet the key constraints for implantation into tortuous blood vessels inaccessible with existing techniques. In vivo electrophysiology recording of local field potentials and single-unit spikes has been selectively achieved in the cortex and the olfactory bulb. Histology analysis of the tissue interface showed minimal immune response and long-term stability. This platform technology can be readily extended as both research tools and medical devices for the detection and intervention of neurological diseases.

Honokiol attenuates mitochondrial fission and cell apoptosis by activating Sirt3 in intracerebral hemorrhage

BACKGROUND

Sirtuin-3 (Sirt3) has been documented to protect against mitochondrial dysfunction and apoptosis. Honokiol (HKL) is a Sirt3 pharmacological activator with reported neuroprotective effects in multiple neurological disorders. The present study aimed to explore the neuroprotective effects of HKL and the role of Sirt3 following intracerebral hemorrhage (ICH).

METHODS

An in vivo ICH model in rats was established by injecting autologous blood into the right basal ganglia. PC12 cells were stimulated with hemin. For the in vivo investigation, the modified Neurological Severity Scores and the Morris water maze test were performed to assess neurological deficits. Hematoxylin-Eosin and Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining were employed to evaluate the histopathology and apoptosis. Immunohistochemical staining was used to investigate the expression of Sirt3. Adenosine triphosphate (ATP) levels were quantified to assess mitochondrial dysfunction. Cell counting kit-8, lactate dehydrogenase assay, and flow cytometry were used to analyze cell vitality and apoptosis in vitro. Immunofluorescence staining was performed to observe mitochondrial morphology and dynamin-related protein 1 (Drp1) localization to mitochondria. Western blot was applied to quantify the expression of Sirt3, Bax, Bcl-2, cleaved-caspase-3, Drp1, phosphorylation of Drp1 at serine-616, and phosphorylation of Drp1 at serine-637 in vivo and in vitro.

RESULTS

HKL treatment alleviated neurological deficits, attenuated the histopathological damage and cell apoptosis, and restored the decreased ATP levels in ICH rats. HKL improved cell survival rate, reduced cell apoptosis, and inhibited mitochondrial fission in PC12 cells. Moreover, both in vivo and in vitro models showed increased phosphorylation of Drp1 at Ser616, and reduced phosphorylation of Drp1 at Ser637. Meanwhile, immunofluorescence co-localization analysis revealed that hemin increased the overlap of Drp1 and mitochondria in PC12 cells. The phosphorylation and mitochondrial translocation of Drp1 were effectively reversed by HKL treatment. Importantly, the selective Sirt3 inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine suppressed these effects.

CONCLUSION

Our findings demonstrated that HKL ameliorated ICH-induced apoptosis and mitochondrial fission by Sirt3, suggesting that HKL has immense prospects for the treatment of ICH.

Downregulation of mitochondrial calcium uptake family 3 attenuates secondary brain injury after intracerebral hemorrhage in rats

Intracerebral hemorrhage (ICH) is one type of stroke with a high incidence and mortality. Mitochondria provide energy for various life processes and regulate calcium-mediated signaling pathways by taking up calcium ions from cytoplasm. Mitochondrial calcium uptake family 3 (MICU3) is a tissue-specific enhancer of mitochondrial calcium uptake. The effects and mechanisms of MICU3 in ICH are unknown. In this study, we aimed to explore the role of MICU3 in ICH in rats and neuronal models. First, we constructed ICH model both in vivo and in vitro and observed increased expression of MICU3. Then lentivirus was transduced to knock down MICU3. We observed that knockdown of MICU3 significantly reduced mitochondrial uptake of calcium in primary neurons. Moreover, the downregulation of MICU3 attenuated cell apoptosis and decreased the accumulation of reactive oxygen species (ROS). Recovery of neurobehavioral and cognitive function also benefited from downregulation of MICU3. The findings demonstrated that MICU3 played an important role in cell apoptosis, oxidative stress, and maintenance of mitochondrial structure and function, and promoted rehabilitation of neurobehavior. In conclusion, MICU3 is expected to be a molecular marker and a potential therapeutic target for ICH.

Effects of magnetically targeted iron oxide@polydopamine-labeled human umbilical cord mesenchymal stem cells in cerebral infarction in mice

Mesenchymal stem cells are a potential therapeutic candidate for cerebral infarction due to their anti-inflammatory proprieties. However, ensuring the engraftment of sufficient cells into the affected brain area remains a challenge. Herein, magnetic targeting techniques were used for the transplantation of a large number of cells noninvasively. Mice subjected to pMCAO surgery were administered MSCs labeled or not with iron oxide@polydopamine nanoparticles by tail vein injection. Iron oxide@polydopamine particles were characterized by transmission electron microscopy, and labeled MSCs were characterized by flow cytometry and their differentiation potential was assessed in vitro. Following the systemic injection of iron oxide@polydopamine-labeled MSCs into pMCAO-induced mices, magnetic navigation increased the MSCs localization to the brain lesion site and reduced the lesion volume. Treatment with iron oxide@polydopamine-labeled MSCs also significantly inhibited M1 microglia polarization and increased M2 microglia cell infiltration. Furthermore, western blotting and immunohistochemical analysis demonstrated that microtubule-associated protein 2 and NeuN levels were upregulated the brain tissue of mice treated with iron oxide@polydopamine-labeled MSCs. Thus, iron oxide@polydopamine-labeled MSCs attenuated brain injury and protected neurons by preventing pro-inflammatory microglia activation. Overall, the proposed iron oxide@polydopamine-labeled MSCs approach may overcome the major drawback of the conventional MSCs therapy for the treatment of cerebral infarction.

Comparative study of extracellular vesicles derived from mesenchymal stem cells and brain endothelial cells attenuating blood-brain barrier permeability via regulating Caveolin-1-dependent ZO-1 and Claudin-5 endocytosis in acute ischemic stroke

BACKGROUND

Blood-brain barrier (BBB) disruption is a major adverse event after ischemic stroke (IS). Caveolin-1 (Cav-1), a scaffolding protein, played multiple roles in BBB permeability after IS, while the pros and cons of Cav-1 on BBB permeability remain controversial. Numerous studies revealed that extracellular vesicles (EVs), especially stem cells derived EVs, exerted therapeutic efficacy on IS; however, the mechanisms of BBB permeability needed to be clearly illustrated. Herein, we compared the protective efficacy on BBB integrity between bone marrow mesenchymal stem cells derived extracellular vesicles (BMSC-EVs) and EVs from brain endothelial cells (BEC-EVs) after acute IS and investigated whether the mechanism was associated with EVs antagonizing Cav-1-dependent tight junction proteins endocytosis.

METHODS

BMSC-EVs and BEC-EVs were isolated and characterized by nanoparticle tracking analysis, western blotting, and transmission electron microscope. Oxygen and glucose deprivation (OGD) treated b. End3 cells were utilized to evaluate brain endothelial cell leakage. CCK-8 and TRITC-dextran leakage assays were used to measure cell viability and transwell monolayer permeability. Permanent middle cerebral artery occlusion (pMCAo) model was established, and EVs were intravenously administered in rats. Animal neurological function tests were applied, and microvessels were isolated from the ischemic cortex. BBB leakage and tight junction proteins were analyzed by Evans Blue (EB) staining and western blotting, respectively. Co-IP assay and Cav-1 siRNA/pcDNA 3.1 vector transfection were employed to verify the endocytosis efficacy of Cav-1 on tight junction proteins.

RESULTS

Both kinds of EVs exerted similar efficacies in reducing the cerebral infarction volume and BBB leakage and enhancing the expressions of ZO-1 and Claudin-5 after 24 h pMCAo in rats. At the same time, BMSC-EVs were outstanding in ameliorating neurological function. Simultaneously, both EVs treatments suppressed the highly expressed Cav-1 in OGD-exposed b. End3 cells and ischemic cerebral microvessels, and this efficacy was more prominent after BMSC-EVs administration. Cav-1 knockdown reduced OGD-treated b. End3 cells monolayer permeability and recovered ZO-1 and Claudin-5 expressions, whereas Cav-1 overexpression aggravated permeability and enhanced the colocalization of Cav-1 with ZO-1 and Claudin-5. Furthermore, Cav-1 overexpression partly reversed the lower cell leakage by BMSC-EVs and BEC-EVs administrations in OGD-treated b. End3 cells.

CONCLUSIONS

Our results demonstrated that Cav-1 aggravated BBB permeability in acute ischemic stroke, and BMSC-EVs exerted similar antagonistic efficacy to BEC-EVs on Cav-1-dependent ZO-1 and Claudin-5 endocytosis. BMSC-EVs treatment was superior in Cav-1 suppression and neurological function amelioration.

Cdh5-mediated Fpn1 deletion exerts neuroprotective effects during the acute phase and inhibitory effects during the recovery phase of ischemic stroke

Ischemic stroke is associated with high mortality and morbidity rates worldwide. However, the molecular mechanisms underlying the neuronal damage incurred by stroke victims remain unclear. It has previously been reported that ischemic stroke can induce an increase in the levels of brain iron, which is an important factor of in the associated brain damage. Ferroportin 1 (FPN1), the only known cellular iron export protein, is found in brain microvascular endothelial cells (BMVECs) at the blood-brain barrier, and is considered the gateway for entry of plasma iron into the central nervous system. Despite the connection of brain iron to neuronal damage, the role of BMVECs FPN1 in ischemic stroke remains unexplored. Herein, we conditionally deleted Fpn1 in mouse endothelial cells (ECs), using VE-cadherin-Cre transgenic mice, and explored the impact on brain iron homeostasis after stroke. Our data demonstrated that Fpn1 knockout in ECs decreased the brain iron levels in mice, attenuated the oxidative stress and inflammatory responses after stroke, and inhibited both ferroptosis and apoptosis, ultimately alleviating neurological impairment and decreasing cerebral infarct volume during the acute phase of ischemic stroke. By contrast, we found that Fpn1 knockout in ECs delayed the recovery of neurological function in mice following ischemic stroke. We also found that ECs Fpn1 knockout decreased the brain iron levels after stroke, exacerbated glial cell proliferation, and inhibited neuronal development, indicating that the diminished brain iron levels hindered the repair of neural injury in mice. In conclusion, our findings reveal a dual consequence of FPN1 deficiency in ECs in the development of ischemic stroke. More specifically, iron deficiency initially exerts a neuroprotective effect during the acute phase of ischemic stroke but inhibits recovery during the later stages. Our findings are important to the development of iron- or FPN1-targeting therapeutics for the treatment of ischemic stroke.

Butyrate promotes post-stroke outcomes in aged mice via interleukin-22

Aging increases the risk of stroke, may exacerbate neuroinflammatory responses, reduce angiogenesis, and promote white matter damage post-stroke, all of which contribute to long-term functional recovery. Butyric acid, an important gut microbial metabolite, showed the highest correlation with the outcomes of ischemic stroke, and butyrate was selected as an effective treatment for aged stroke mice. Here, we tested the neurorestorative effect and potential therapeutic mechanisms of butyrate in aged mice with stroke. Aged male C57BL/6 J mice (17-19 months) were subjected to photothrombotic stroke. We performed butyrate supplementation in the drinking water for 3 weeks before surgery until 14 days after the stroke. At 14 days after ischemic stroke, white matter damage, leukocyte infiltration, and blood-brain barrier permeability were all decreased in the aged stroke mice that received the butyrate treatment, which also improved neurological outcomes by stimulating angiogenesis. Stroke reduces the level of interleukin-22 (IL-22) and butyrate treatment significantly enhanced IL-22 expression in the brain. To further validate the mechanisms of butyrate promoting neurological function after stroke, monoclonal antibodies were used to block IL-22 in aged stroke mice when butyrate treatment was provided. Blocking IL-22 in butyrate-treated aged stroke fails to improve functional outcomes and attenuated butyrate-induced angiogenesis, increased axon/white matter density and blood-brain barrier (BBB) integrity, but has no effect on inflammatory cells infiltration. In conclusion, butyrate improves outcomes in aged mice after stroke by promoting angiogenesis and BBB integrity and reducing leukocyte infiltration. To some extent, IL-22 may contribute to butyrate treatment induced vascular remodeling and increased BBB integrity responses in aged stroke mice.

Transient Receptor Potential Mucolipin-1 Participates in Intracerebral Hemorrhage-Induced Secondary Brain Injury by Inducing Neuroinflammation and Neuronal Cell Death

Transient receptor potential mucolipin-1 (TRPML1) is the most abundantly and widely expressed channel protein in the TRP family. While numerous studies have been conducted involving many aspects of TRPML1, such as its role in cell biology, oncology, and neurodegenerative diseases, there are limited reports about what role it plays in intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI). Here we examined the function of TRPML1 in ICH-induced SBI. The caudal arterial blood of rats was injected into the caudate nucleus of basal ganglia to establish an experimental ICH model. We observed that lentivirus downregulated the expression level of TRPML1 and chemical agonist promoted the enzyme activity of TRPML1. The results indicated that the protein levels of TRPML1 in brain tissues increased 24 h after ICH. These results suggested that downregulated TRPML1 could significantly reduce inflammatory cytokines, and ICH induced the production of LDH and ROS. Furthermore, TRPML1 knockout relieved ICH-induced neuronal cell death and degeneration, and declines in learning and memory after ICH could be improved by downregulating the expression of TRPML1. In addition, chemical agonist-expressed TRPML1 showed the opposite effect and exacerbated SBI after ICH. In summary, this study demonstrated that TRPML1 contributed to brain injury after ICH, and downregulating TRPML1 could improve ICH-induced SBI, suggesting a potential target for ICH therapy.

Data of MSCs combined with LITUS treatment to improve cognitive impairment in a moderate traumatic brain injury model in rats

Here, we treated moderately traumatic brain injury (TBI) rats with different modalities, including transplantation with mesenchymal stem cells (MSCs), treatment with low-intensity transcranial ultrasound stimulation (LITUS), and a combination of the two. After the TBI rat model was established, MSCs (in situ injection within 24 h after injury), LITUS (continuous uninterrupted treatment for 28 days) or combined MSCs + LITUS were administered, and mNSS score, performance of behavior and multiple protein levels were compared between groups by behavioral observation, neurological function assessment and pathological analysis. Nestin, neuron-specific enolase (NSE), growth-associated protein 43 (GAP-43) and postsynaptic density protein (PSD-95) were significantly increased and glial fibrillary acidic protein (GFAP) was significantly decreased in the hippocampus of rats in the combination treatment group; brain-derived neurotrophic factor (BDNF), tumor necrosis factor-α (TNF-α) and aquaporin-4 (AQP-4) were significantly decreased in the injured peripheral cortex. The result of mNSS scores was: TBI group > LITUS group > MSCs group > MSCs+LITUS group > sham group. The alternate correct rate of Y-maze was: sham group > MSCs+LITUS group > MSCs group > LITUS group > TBI group. This data compares the efficacy of MSCs, LITUS, and combination therapy on the level expression of stem cell differentiation related proteins, synaptic plasticity-related proteins, neurotrophic factors, inflammatory factors, and edema-related proteins after TBI by quantitative pathological examination. For a complete description, interpretation, and discussion of the data refer to the article in press [1].

Resveratrol Inhibits Activation of Microglia after Stroke through Triggering Translocation of Smo to Primary Cilia

Activated microglia act as a double-edged sword for stroke. In the acute phase of stroke, activated microglia might deteriorate neurological function. Therefore, it is of great clinical transforming potential to explore drugs or methods that can inhibit abnormal activation of microglia in the acute phase of stroke to improve neurological function after stroke. Resveratrol has a potential effect of regulating microglial activation and anti-inflammation. However, the molecular mechanism of resveratrol-inhibiting microglial activation has not been fully clarified. Smoothened (Smo) belongs to the Hedgehog (Hh) signaling pathway. Smo activation is the critical step that transmits the Hh signal across the primary cilia to the cytoplasm. Moreover, activated Smo can improve neurological function via regulating oxidative stress, inflammation, apoptosis, neurogenesis, oligodendrogenesis, axonal remodeling, and so on. More studies have indicated that resveratrol can activate Smo. However, it is currently unknown whether resveratrol inhibits microglial activation via Smo. Therefore, in this study, N9 microglia in vitro and mice in vivo were used to investigate whether resveratrol inhibited microglial activation after oxygen-glucose deprivation/reoxygenation (OGD/R) or middle cerebral artery occlusion/reperfusion (MCAO/R) injury and improved functional outcome via triggering translocation of Smo in primary cilia. We definitively found that microglia had primary cilia; resveratrol partially inhibited activation and inflammation of microglia, improved functional outcome after OGD/R and MCAO/R injury, and triggered translocation of Smo to primary cilia. On the contrary, Smo antagonist cyclopamine canceled the above effects of resveratrol. The study suggested that Smo receptor might be a therapeutic target of resveratrol for contributing to inhibit microglial activation in the acute phase of stroke.

Aging-Associated Thyroid Dysfunction Contributes to Oxidative Stress and Worsened Functional Outcomes Following Traumatic Brain Injury

The incidence of traumatic brain injury (TBI) increases dramatically with advanced age and accumulating evidence indicates that age is one of the important predictors of an unfavorable prognosis after brain trauma. Unfortunately, thus far, evidence-based effective therapeutics for geriatric TBI is limited. By using middle-aged animals, we first confirm that there is an age-related change in TBI susceptibility manifested by increased inflammatory events, neuronal death and impaired functional outcomes in motor and cognitive behaviors. Since thyroid hormones function as endogenous regulators of oxidative stress, we postulate that age-related thyroid dysfunction could be a crucial pathology in the increased TBI severity. By surgically removing the thyroid glands, which recapitulates the age-related increase in TBI-susceptible phenotypes, we provide direct evidence showing that endogenous thyroid hormone-dependent compensatory regulation of antioxidant events modulates individual TBI susceptibility, which is abolished in aged or thyroidectomized individuals. The antioxidant capacity of melatonin is well-known, and we found acute melatonin treatment but not liothyronine (T3) supplementation improved the TBI-susceptible phenotypes of oxidative stress, excitotoxic neuronal loss and promotes functional recovery in the aged individuals with thyroid dysfunction. Our study suggests that monitoring thyroid function and acute administration of melatonin could be feasible therapeutics in the management of geriatric-TBI in clinic.

Delayed NLRP3 inflammasome inhibition ameliorates subacute stroke progression in mice

BACKGROUND

Ischemic stroke immediately evokes a strong neuro-inflammatory response within the vascular compartment, which contributes to primary infarct development under vessel occlusion as well as further infarct growth despite recanalization, referred to as ischemia/reperfusion injury. Later, in the subacute phase of stroke (beyond day 1 after recanalization), further inflammatory processes within the brain parenchyma follow. Whether this second wave of parenchymal inflammation contributes to an additional/secondary increase in infarct volumes and bears the potential to be pharmacologically targeted remains elusive. We addressed the role of the NLR-family pyrin domain-containing protein 3 (NLRP3) inflammasome in the subacute phase of ischemic stroke.

METHODS

Focal cerebral ischemia was induced in C57Bl/6 mice by a 30-min transient middle cerebral artery occlusion (tMCAO). Animals were treated with the NLRP3 inhibitor MCC950 therapeutically 24 h after or prophylactically before tMCAO. Stroke outcome, including infarct size and functional deficits as well as the local inflammatory response, was assessed on day 7 after tMCAO.

RESULTS

Infarct sizes on day 7 after tMCAO decreased about 35% after delayed and about 60% after prophylactic NLRP3 inhibition compared to vehicle. Functionally, pharmacological inhibition of NLRP3 mitigated the local inflammatory response in the ischemic brain as indicated by reduction of infiltrating immune cells and reactive astrogliosis.

CONCLUSIONS

Our results demonstrate that the NLRP3 inflammasome continues to drive neuroinflammation within the subacute stroke phase. NLRP3 inflammasome inhibition leads to a better long-term outcome-even when administered with a delay of 1 day after stroke induction, indicating ongoing inflammation-driven infarct progression. These findings may pave the way for eagerly awaited delayed treatment options in ischemic stroke.

Suppressive role of lovastatin in intracerebral hemorrhage through repression of autophagy

Statins possess critical function in the brain. Here, we intended to investigate the role of lovastatin in brain damage after intracerebral hemorrhage (ICH). A collagenase-induced ICH rat model was established followed by lovastatin treatment. Then, the effect of lovastatin on ICH-induced brain damage was explored with cognitive function, learning and memory abilities, and neurological damage of rats analyzed. Besides, brain water content, number of degenerate neurons, Nissl's body, and apoptosis of neurons were detected. Oxidative stress levels, inflammation, and autophagy levels in ICH were measured after treatment of lovastatin. Lovastatin improved the cognitive impairment of rats, enhanced their spatial learning and memory abilities, reduced nervous system damage, lesion area, and brain water content after ICH. Lovastatin was capable of reducing the number of degenerated neurons, the apoptosis level, autophagy level, and increasing the number of Nissl's body. Lovastatin inhibited the oxidative stress response and inflammatory factors in the brain tissue after ICH, and increased the expression of anti-inflammatory factor IL-10. Lovastatin inhibited AMPK/mTOR signaling pathway after ICH. Our study highlighted the suppressive role of lovastatin in ICH-induced brain damage.

Axin1 participates in blood-brain barrier protection during experimental ischemic stroke via phosphorylation at Thr485 in rats

Axin1 takes an important part in a variety of signaling pathway, such as MEKK1, GSK3β, and β-catenin, and plays a variety of physiological functions; but its effects on the brain-blood barrier (BBB) and stroke remain unclear. To explore the effects and underlying mechanisms of Axin1 on the BBB in ischemic stroke, Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO). Human brain microvascular endothelial cells (HBMEC) were subjected to oxygen/glucose deprivation/reoxygenation (OGD/R) to imitate ischemia/reperfusion (I/R) injury. We found that Axin1 was upregulated in HBMEC after OGD without reoxygenation, and downregulated in the injured hemisphere after MCAO without reperfusion. Tight junction (TJ) proteins were upregulated both in HBMEC after OGD without reoxygenation and in ischemic penumbra of the injured hemisphere in rats after MCAO without reperfusion. TJ proteins were downregulated after MCAO/R in rats. Overexpression of Axin1 upregulated the levels of TJ proteins, which alleviated BBB permeability, reduced infarction volume, and ultimately improved neurological behavioral indicators after I/R injury. Furthermore, inhibiting phosphorylation of Axin1 at Thr485 notably increased the expression of Snail and decreased the expression of TJ proteins. Our findings demonstrate that Axin1 participates in BBB protection and improvement of neurological functions during ischemic stroke by regulating TJ proteins. Axin1 may serve as a potential novel candidate to protect BBB and relieve brain injury.

Therapeutic effects of CD133 + Exosomes on liver function after stroke in type 2 diabetic mice

Background and purpose

Non-alcoholic fatty liver disease (NAFLD) is known to adversely affect stroke recovery. However, few studies investigate how stroke elicits liver dysfunction, particularly, how stroke in type 2 diabetes mellitus (T2DM) exacerbates progression of NAFLD. In this study, we test whether exosomes harvested from human umbilical cord blood (HUCBC) derived CD133 + cells (CD133 + Exo) improves neuro-cognitive outcome as well as reduces liver dysfunction in T2DM female mice.

Methods

Female, adult non-DM and T2DM mice subjected to stroke presence or absence were considered. T2DM-stroke mice were randomly assigned to receive PBS or Exosome treatment group. CD133 + Exo (20 μg/200 μl PBS, i.v.) was administered once at 3 days after stroke. Evaluation of neurological (mNSS, adhesive removal test) and cognitive function [novel object recognition (NOR) test, odor test] was performed. Mice were sacrificed at 28 days after stroke and brain, liver, and serum were harvested.

Results

Stroke induces severe and significant short-term and long-term neurological and cognitive deficits which were worse in T2DM mice compared to non-DM mice. CD133 + Exo treatment of T2DM-stroke mice significantly improved neurological function and cognitive outcome indicated by improved discrimination index in the NOR and odor tests compared to control T2DM-stroke mice. CD133 + Exo treatment of T2DM stroke significantly increased vascular and white matter/axon remodeling in the ischemic brain compared to T2DM-stroke mice. However, there were no differences in the lesion volume between non-DM stroke, T2DM-stroke and CD133 + Exo treated T2DM-stroke mice. In T2DM mice, stroke induced earlier and higher TLR4, NLRP3, and cytokine expression (SAA, IL1β, IL6, TNFα) in the liver compared to heart and kidney, as measured by Western blot. T2DM-stroke mice exhibited worse NAFLD progression with increased liver steatosis, hepatocellular ballooning, fibrosis, serum ALT activity, and higher NAFLD Activity Score compared to T2DM mice and non-DM-stroke mice, while CD133 + Exo treatment significantly attenuated the progression of NAFLD in T2DM stroke mice.

Conclusion

Treatment of female T2DM-stroke mice with CD133 + Exo significantly reduces the progression of NAFLD/NASH and improves neurological and cognitive function compared to control T2DM-stroke mice.