Neuroprotection by interleukin-6 is mediated by signal transducer and activator of transcription 3 and antioxidative signaling in ischemic stroke

Emerging strategies for nerve repair and regeneration in ischemic stroke: neural stem cell therapy

Ischemic stroke is a major cause of mortality and disability worldwide, with limited treatment options available in clinical practice. The emergence of stem cell therapy has provided new hope to the field of stroke treatment via the restoration of brain neuron function. Exogenous neural stem cells are beneficial not only in cell replacement but also through the bystander effect. Neural stem cells regulate multiple physiological responses, including nerve repair, endogenous regeneration, immune function, and blood-brain barrier permeability, through the secretion of bioactive substances, including extracellular vesicles/exosomes. However, due to the complex microenvironment of ischemic cerebrovascular events and the low survival rate of neural stem cells following transplantation, limitations in the treatment effect remain unresolved. In this paper, we provide a detailed summary of the potential mechanisms of neural stem cell therapy for the treatment of ischemic stroke, review current neural stem cell therapeutic strategies and clinical trial results, and summarize the latest advancements in neural stem cell engineering to improve the survival rate of neural stem cells. We hope that this review could help provide insight into the therapeutic potential of neural stem cells and guide future scientific endeavors on neural stem cells.

Allogeneic mesenchymal stem cells may be a viable treatment modality in cerebral palsy

BACKGROUND

Cerebral palsy (CP) describes a group of disorders affecting movement, balance, and posture. Disturbances in motor functions constitute the main body of CP symptoms. These symptoms surface in early childhood and patients are affected for the rest of their lives. Currently, treatment involves various pharmacotherapies for different types of CP, including antiepileptics for epilepsy and Botox A for focal spasticity. However, none of these methods can provide full symptom relief. This has prompted researchers to look for new treatment modalities, one of which is mesenchymal stem cell therapy (MSCT). Despite being a promising tool and offering a wide array of possibilities, mesenchymal stem cells (MSCs) still need to be investigated for their efficacy and safety.

AIM

To analyze the efficacy and safety of MSCT in CP patients.

METHODS

Our sample consists of four CP patients who cannot stand or walk without external support. All of these cases received allogeneic MSCT six times as 1 × 106/kg intrathecally, intravenously, and intramuscularly using umbilical cord-derived MSCs (UC-MSC). We monitored and assessed the patients pre- and post-treatment using the Wee Functional Independence Measure (WeeFIM), Gross Motor Function Classification System (GMFCS), and Manual Ability Classification Scale (MACS) instruments. We utilized the Modified Ashworth Scale (MAS) to measure spasticity.

RESULTS

We found significant improvements in MAS scores after the intervention on both sides. Two months: Right χ2 = 4000, P = 0.046, left χ2 = 4000, P = 0.046; four months: Right χ2 = 4000, P = 0.046, left χ2 = 4000, P = 0.046; 12 months: Right χ2 = 4000, P = 0.046, left χ2 = 4000, P = 0.046. However, there was no significant difference in motor functions based on WeeFIM results (P > 0.05). GMFCS and MACS scores differed significantly at 12 months after the intervention (P = 0.046, P = 0.046). Finally, there was no significant change in cognitive functions (P > 0.05).

CONCLUSION

In light of our findings, we believe that UC-MSC therapy has a positive effect on spasticity, and it partially improves motor functions.

Ginsenoside Re protects against kainate-induced neurotoxicity in mice by attenuating mitochondrial dysfunction through activation of the signal transducers and activators of transcription 3 signaling

It was demonstrated that ginsenosides exert anti-convulsive potentials and interleukin-6 (IL-6) is protective from excitotoxicity induced by kainate (KA), a model of temporal lobe epilepsy. Ginsenosides-mediated mitochondrial recovery is essential for attenuating KA-induced neurotoxicity, however, little is known about the effects of ginsenoside Re (GRe), one of the major ginsenosides. In this study, GRe significantly attenuated KA-induced seizures in mice. KA-induced redox changes were more evident in mitochondrial fraction than in cytosolic fraction in the hippocampus of mice. GRe significantly attenuated KA-induced mitochondrial oxidative stress (i.e. increases in reactive oxygen species, 4-hydroxynonenal, and protein carbonyl) and mitochondrial dysfunction (i.e. the increase in intra-mitochondrial Ca2+ and the decrease in mitochondrial membrane potential). GRe or mitochondrial protectant cyclosporin A restored phospho-signal transducers and activators of transcription 3 (STAT3) and IL-6 levels reduced by KA, and the effects of GRe were reversed by the JAK2 inhibitor AG490 and the mitochondrial toxin 3-nitropropionic acid (3-NP). Thus, we used IL-6 knockout (KO) mice to investigate whether the interaction between STAT3 and IL-6 is involved in the GRe effects. Importantly, KA-induced reduction of manganese superoxide dismutase (SOD-2) levels and neurodegeneration (i.e. astroglial inhibition, microglial activation, and neuronal loss) were more prominent in IL-6 KO than in wild-type (WT) mice. These KA-induced detrimental effects were attenuated by GRe in WT and, unexpectedly, IL-6 KO mice, which were counteracted by AG490 and 3-NP. Our results suggest that GRe attenuates KA-induced neurodegeneration via modulating mitochondrial oxidative burden, mitochondrial dysfunction, and STAT3 signaling in mice.

Ischemia Reperfusion Injury Induced Blood Brain Barrier Dysfunction and the Involved Molecular Mechanism

Stroke is characterized by the abrupt failure of blood flow to a specific brain region, resulting in insufficient supply of oxygen and glucose to the ischemic tissues. Timely reperfusion of blood flow can rescue dying tissue but can also lead to secondary damage to both the infarcted tissues and the blood-brain barrier, known as ischemia/reperfusion injury. Both primary and secondary damage result in biphasic opening of the blood-brain barrier, leading to blood-brain barrier dysfunction and vasogenic edema. Importantly, blood-brain barrier dysfunction, inflammation, and microglial activation are critical factors that worsen stroke outcomes. Activated microglia secrete numerous cytokines, chemokines, and inflammatory factors during neuroinflammation, contributing to the second opening of the blood-brain barrier and worsening the outcome of ischemic stroke. TNF-α, IL-1β, IL-6, and other microglia-derived molecules have been shown to be involved in the breakdown of blood-brain barrier. Additionally, other non-microglia-derived molecules such as RNA, HSPs, and transporter proteins also participate in the blood-brain barrier breakdown process after ischemic stroke, either in the primary damage stage directly influencing tight junction proteins and endothelial cells, or in the secondary damage stage participating in the following neuroinflammation. This review summarizes the cellular and molecular components of the blood-brain barrier and concludes the association of microglia-derived and non-microglia-derived molecules with blood-brain barrier dysfunction and its underlying mechanisms.

Neonatal asphyxia as an inflammatory disease: Reactive oxygen species and cytokines

Neonatologists resuscitate asphyxiated neonates by every available means, including positive ventilation, oxygen therapy, and drugs. Asphyxiated neonates sometimes present symptoms that mimic those of inflammation, such as fever and edema. The main pathophysiology of the asphyxia is inflammation caused by hypoxic-ischemic reperfusion. At birth or in the perinatal period, neonates may suffer several, hypoxic insults, which can activate inflammatory cells and inflammatory mediator production leading to the release of larger quantities of reactive oxygen species (ROS). This in turn triggers the production of oxygen stress-induced high mobility group box-1 (HMGB-1), an endogenous damage-associated molecular patterns (DAMPs) protein bound to toll-like receptor (TLR) -4, which activates nuclear factor-kappa B (NF-κB), resulting in the production of excess inflammatory mediators. ROS and inflammatory mediators are produced not only in activated inflammatory cells but also in non-immune cells, such as endothelial cells. Hypothermia inhibits pro-inflammatory mediators. A combination therapy of hypothermia and medications, such as erythropoietin and melatonin, is attracting attention now. These medications have both anti-oxidant and anti-inflammatory effects. As the inflammatory response and oxidative stress play a critical role in the pathophysiology of neonatal asphyxia, these drugs may contribute to improving patient outcomes.

Viral-induced neuroinflammation: Different mechanisms converging to similar exacerbated glial responses

There is increasing evidence that viral infections are the source/origin of various types of encephalitis, encephalomyelitis, and other neurological and cognitive disorders. While the involvement of certain viruses, such as the Nipah virus and measles virus, is known, the mechanisms of neural invasion and the factors that trigger intense immune reactions are not fully understood. Based on recent publications, this review discusses the role of the immune response, interactions between viruses and glial cells, and cytokine mediators in the development of inflammatory diseases in the central nervous system. It also highlights the significant gaps in knowledge regarding these mechanisms.

JAK2/STAT3 pathway mediates neuroprotective and pro-angiogenic treatment effects of adult human neural stem cells in middle cerebral artery occlusion stroke animal models

Mismatches between pre-clinical and clinical results of stem cell therapeutics for ischemic stroke limit their clinical applicability. To overcome these discrepancies, precise planning of pre-clinical experiments that can be translated to clinical trials and the scientific elucidation of treatment mechanisms is important. In this study, adult human neural stem cells (ahNSCs) derived from temporal lobe surgical samples were used (to avoid ethical and safety issues), and their therapeutic effects on ischemic stroke were examined using middle cerebral artery occlusion animal models. 5 × 10⁵ ahNSCs was directly injected into the lateral ventricle of contralateral brain hemispheres of immune suppressed rat stroke models at the subacute phase of stroke. Compared with the mock-treated group, ahNSCs reduced brain tissue atrophy and neurological sensorimotor and memory functional loss. Tissue analysis demonstrated that the significant therapeutic effects were mediated by the neuroprotective and pro-angiogenic activities of ahNSCs, which preserved neurons in ischemic brain areas and decreased reactive astrogliosis and microglial activation. The neuroprotective and pro-angiogenic effects of ahNSCs were validated in in vitro stroke models and were induced by paracrine factors excreted by ahNSCs. When the JAK2/STAT3 signaling pathway was inhibited by a specific inhibitor, AG490, the paracrine neuroprotective and pro-angiogenic effects of ahNSCs were reversed. This pre-clinical study that closely simulated clinical settings and provided treatment mechanisms of ahNSCs for ischemic stroke may aid the development of protocols for subsequent clinical trials of ahNSCs and the realization of clinically available stem cell therapeutics for ischemic stroke.

Mechanism of Salvia miltiorrhiza Bge. for the Treatment of Ischemic Stroke Based on Bioinformatics and Network Pharmacology

Background and Purpose. A large number of pharmacological experiments have proved that many components of Salvia miltiorrhiza Bge. have neuroprotective, anti-inflammatory, and antioxidant effects. Middle cerebral artery occlusion (MCAO) models treated with Salvia miltiorrhiza Bge. can significantly reduce the infarct size and change the pathological morphology of brain tissue. However, not only the internal mechanism but also the material basis is unclear to researchers. Our research aims to elucidate the potential effective material basis and molecular internal mechanism between Salvia miltiorrhiza Bge. and stroke. Methods. In this study, SymMap was used to screen the 50 bioactive scored components and 65 putative targets of Salvia miltiorrhiza Bge., and their targets were standardized using the UniProt platform. The disease targets related to stroke were collected by comparative toxicogenomics database (CTD), GeneCards, and quantitative structure-activity relationships-TargetNet (QSAR-TargetNet). Thereafter, the protein-protein interaction (PPI) network was constructed using the STRING platform and visualized by Cytoscape (3.8.2) software. Then, the Metascape platform was used to analyze the Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Cytoscape (3.7.2) software was also used to construct the network of the “herb-component-target-pathway.” We found that Tanshinol B, Tanshinol A, Przewaquinone C, Tanshinone II, and other main components of Salvia miltiorrhiza Bge. may regulate neurotransmitters and neurological function. Therefore, we speculate Salvia miltiorrhiza Bge. has a neuroprotective effect. For further verification, potential core targets (STAT3, MMP2, ESR1, TERT, and MMP9 proteins) for ischemic stroke and core active ingredients (Tanshinol A, Tanshinol B, Tanshinone II A, and Przewaquinone C) for Salvia miltiorrhiza Bge. were further verified by molecular docking. Results. Our findings revealed that Tanshinol A, Tanshinol B, Tanshinone II A, and Przewaquinone C as the main component of Salvia miltiorrhiza Bge. may have a neuroprotective effect against ischemic stroke, which provides a new understanding for the development of therapies for the prevention and treatment of ischemic stroke.

Transplantation of Astrocytic Mitochondria Modulates Neuronal Antioxidant Defense and Neuroplasticity and Promotes Functional Recovery after Intracerebral Hemorrhage

Astrocytes release functional mitochondria (Mt) that play regulatory and prosurvival functions on entering adjacent cells. We recently demonstrated that these released Mts could enter microglia to promote their reparative/prophagocytic phenotype that assists in hematoma cleanup and neurological recovery after intracerebral hemorrhage (ICH). However, the relevance of astrocytic Mt transfer into neurons in protecting brain after ICH is unclear. Here, we found that ICH causes a robust increase in superoxide generation and elevated oxidative damage that coincides with loss of the mitochondrial enzyme manganese superoxide dismutase (Mn-SOD). The damaging effect of ICH was reversed by intravenous transplantation of astrocytic Mt, which on entering the brain (and neurons), restored Mn-SOD levels and reduced neurological deficits in male mice subjected to ICH. Using an in vitro ICH-like injury model in cultured neurons, we established that astrocytic Mt on entering neurons prevented reactive oxygen species-induced oxidative stress and neuronal death by restoring neuronal Mn-SOD levels while at the same time promoted neurite extension and upregulation of synaptogenesis-related gene expression. Furthermore, we found that Mt genome-encoded small peptide humanin, which is normally abundant in Mt, could simulate Mt-transfer effect on neuronal Mn-SOD expression, oxidative stress, and neuroplasticity under ICH-like injury. This study demonstrates that adoptive astrocytic Mt transfer enhances neuronal Mn-SOD-mediated antioxidative defense and neuroplasticity in the brain, which potentiate functional recovery following ICH.SIGNIFICANCE STATEMENT Mitochondrial dysfunction and antioxidant defense play essential roles in brain damage after ICH. Astrocytes release functional Mt that enters adjacent cells to help brain homeostatic function. Here, we show that systemic transplantation of astrocytic Mt restores ICH-impaired neuronal antioxidative defense, enhances neurite outgrowth, and improves stroke recovery after ICH. Our study suggests that systemic transplantation of astrocytic Mt could be considered as a novel and potentially promising strategy for ICH treatment.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.

Early-phase administration of human amnion-derived stem cells ameliorates neurobehavioral deficits of intracerebral hemorrhage by suppressing local inflammation and apoptosis

Background

Intracerebral hemorrhage (ICH) is a significant cause of death and disabilities. Recently, cell therapies using mesenchymal stem cells have been shown to improve ICH-induced neurobehavioral deficits. Based on these findings, we designed this study to evaluate the therapeutic efficacy and underlying mechanisms by which human amnion-derived stem cells (hAMSCs) would ameliorate neurobehavioral deficits of ICH-bearing hosts.

Methods

hAMSCs were induced from amnia obtained by cesarean section and administered intravenously to ICH-bearing mice during the acute phase. The mice were then subject to multitask neurobehavioral tests at the subacute phase. We attempted to optimize the dosage and timing of the hAMSC administrations. In parallel with the hAMSCs, a tenfold higher dose of human adipose-derived stem cells (ADSCs) were used as an experimental control. Specimens were obtained from the ICH lesions to conduct immunostaining, flow cytometry, and Western blotting to elucidate the underlying mechanisms of the hAMSC treatment.

Results

The intravenous administration of hAMSCs to the ICH-bearing mice effectively improved their neurobehavioral deficits, particularly when the treatment was initiated at Day 1 after the ICH induction. Of note, the hAMSCs promoted clinical efficacy equivalent to or better than that of hADSCs at 1/10 the cell number. The systemically administered hAMSCs were found in the ICH lesions along with the local accumulation of macrophages/microglia. In detail, the hAMSC treatment decreased the number of CD11b⁺CD45⁺ and Ly6G⁺ cells in the ICH lesions, while splenocytes were not affected. Moreover, the hAMSC treatment decreased the number of apoptotic cells in the ICH lesions. These results were associated with suppression of the protein expression levels of macrophage-related factors iNOS and TNFα.

Conclusions

Intravenous hAMSC administration during the acute phase would improve ICH-induced neurobehavioral disorders. The underlying mechanism was suggested to be the suppression of subacute inflammation and apoptosis by suppressing macrophage/microglia cell numbers and macrophage functions (such as TNFα and iNOS). From a clinical point of view, hAMSC-based treatment may be a novel strategy for the treatment of ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02411-3.

Jak2 Inhibitor AG490 Improved Poststroke Central and Peripheral Inflammation and Metabolic Abnormalities in a Rat Model of Ischemic Stroke

Poststroke hyperglycemia and inflammation have been implicated in the pathogenesis of stroke. Janus Kinase 2 (Jak2), a catalytic signaling component for cytokine receptors such as Interleukin-6 (IL-6), has inflammatory and metabolic properties. This study aimed to investigate the roles of Jak2 in poststroke inflammation and metabolic abnormality in a rat model of permanent cerebral ischemia. Pretreatment with Jak2 inhibitor AG490 ameliorated neurological deficit, brain infarction, edema, oxidative stress, inflammation, caspase-3 activation, and Zonula Occludens-1 (ZO-1) reduction. Moreover, in injured cortical tissues, Tumor Necrosis Factor-α, IL-1β, and IL-6 levels were reduced with concurrent decreased NF-κB p65 phosphorylation, Signal Transducers and Activators of Transcription 3 phosphorylation, Ubiquitin Protein Ligase E3 Component N-Recognin 1 expression, and Matrix Metalloproteinase activity. In the in vitro study on bEnd.3 endothelial cells, AG490 diminished IL-6-induced endothelial barrier disruption by decreasing ZO-1 decline. Metabolically, administration of AG490 lowered fasting glucose, with improvements in glucose intolerance, plasma-free fatty acids, and plasma C Reactive Proteins. In conclusion, AG490 improved the inflammation and oxidative stress of neuronal, hepatic, and muscle tissues of stroke rats as well as impairing insulin signaling in the liver and skeletal muscles. Therefore, Jak2 blockades may have benefits for combating poststroke central and peripheral inflammation, and metabolic abnormalities.

Role of IL-6 in the regulation of neuronal development, survival and function

The pleiotropic cytokine interleukin-6 (IL-6) is emerging as a molecule with both beneficial and destructive potentials. It can exert opposing actions triggering either neuron survival after injury or causing neurodegeneration and cell death in neurodegenerative or neuropathic disorders. Importantly, neurons respond differently to IL-6 and this critically depends on their environment and whether they are located in the peripheral or the central nervous system. In addition to its hub regulator role in inflammation, IL-6 is recently emerging as an important regulator of neuron function in health and disease, offering exciting possibilities for more mechanistic insight into the pathogenesis of mental, neurodegenerative and pain disorders and for developing novel therapies for diseases with neuroimmune and neurogenic pathogenic components.

Programmed cell death in stem cell-based therapy: Mechanisms and clinical applications

Stem cell-based therapy raises hopes for a better approach to promoting tissue repair and functional recovery. However, transplanted stem cells show a high death percentage, creating challenges to successful transplantation and prognosis. Thus, it is necessary to investigate the mechanisms underlying stem cell death, such as apoptotic cascade activation, excessive autophagy, inflammatory response, reactive oxygen species, excitotoxicity, and ischemia/hypoxia. Targeting the molecular pathways involved may be an efficient strategy to enhance stem cell viability and maximize transplantation success. Notably, a more complex network of cell death receives more attention than one crucial pathway in determining stem cell fate, highlighting the challenges in exploring mechanisms and therapeutic targets. In this review, we focus on programmed cell death in transplanted stem cells. We also discuss some promising strategies and challenges in promoting survival for further study.

A Highly Selective In Vitro JNK3 Inhibitor, FMU200, Restores Mitochondrial Membrane Potential and Reduces Oxidative Stress and Apoptosis in SH-SY5Y Cells

Current treatments for neurodegenerative diseases (ND) are symptomatic and do not affect disease progression. Slowing this progression remains a crucial unmet need for patients and their families. c-Jun N-terminal kinase 3 (JNK3) are related to several ND hallmarks including apoptosis, oxidative stress, excitotoxicity, mitochondrial dysfunction, and neuroinflammation. JNK inhibitors can play an important role in addressing neuroprotection. This research aims to evaluate the neuroprotective, anti-inflammatory, and antioxidant effects of a synthetic compound (FMU200) with known JNK3 inhibitory activity in SH-SY5Y and RAW264.7 cell lines. SH-SY5Y cells were pretreated with FMU200 and cell damage was induced by 6-hydroxydopamine (6-OHDA) or hydrogen peroxide (H₂O₂). Cell viability and neuroprotective effect were assessed with an MTT assay. Flow cytometric analysis was performed to evaluate cell apoptosis. The H₂O₂-induced reactive oxygen species (ROS) generation and mitochondrial membrane potential (ΔΨm) were evaluated by DCFDA and JC-1 assays, respectively. The anti-inflammatory effect was determined in LPS-induced RAW264.7 cells by ELISA assay. In undifferentiated SH-SY5Y cells, FMU200 decreased neurotoxicity induced by 6-OHDA in approximately 20%. In RA-differentiated cells, FMU200 diminished cell death in approximately 40% and 90% after 24 and 48 h treatment, respectively. FMU200 reduced both early and late apoptotic cells, decreased ROS levels, restored mitochondrial membrane potential, and downregulated JNK phosphorylation after H₂O₂ exposure. In LPS-stimulated RAW264.7 cells, FMU200 reduced TNF-α levels after a 3 h treatment. FMU200 protects neuroblastoma SH-SY5Y cells against 6-OHDA- and H₂O₂-induced apoptosis, which may result from suppressing the JNK pathways. Our findings show that FMU200 can be a useful candidate for the treatment of neurodegenerative disorders.

The utilization of small non-mammals in traumatic brain injury research: A systematic review

Traumatic brain injury (TBI) is the leading cause of death and disability worldwide and has complicated underlying pathophysiology. Numerous TBI animal models have been developed over the past decade to effectively mimic the human TBI pathophysiology. These models are of mostly mammalian origin including rodents and non-human primates. However, the mammalian models demanded higher costs and have lower throughput often limiting the progress in TBI research. Thus, this systematic review aims to discuss the potential benefits of non-mammalian TBI models in terms of their face validity in resembling human TBI. Three databases were searched as follows: PubMed, Scopus, and Embase, for original articles relating to non-mammalian TBI models, published between January 2010 and December 2019. A total of 29 articles were selected based on PRISMA model for critical appraisal. Zebrafish, both larvae and adult, was found to be the most utilized non-mammalian TBI model in the current literature, followed by the fruit fly and roundworm. In conclusion, non-mammalian TBI models have advantages over mammalian models especially for rapid, cost-effective, and reproducible screening of effective treatment strategies and provide an opportunity to expedite the advancement of TBI research.

New insights into targeting mitochondria in ischemic injury

Stroke is the leading cause of adult disability and death worldwide. Mitochondrial dysfunction has been recognized as a marker of neuronal death during ischemic stroke. Maintaining the function of mitochondria is important for improving the survival of neurons and maintaining neuronal function. Damaged mitochondria induce neuronal cell apoptosis by releasing reactive oxygen species (ROS) and pro-apoptotic factors. Mitochondrial fission and fusion processes and mitophagy are of great importance to mitochondrial quality control. This paper reviews the dynamic changes in mitochondria, the roles of mitochondria in different cell types, and related signaling pathways in ischemic stroke. This review describes in detail the role of mitochondria in the process of neuronal injury and protection in cerebral ischemia, and integrates neuroprotective drugs targeting mitochondria in recent years, which may provide a theoretical basis for the progress of treatment of ischemic stroke. The potential of mitochondrial-targeted therapy is also emphasized, which provides valuable insights for clinical research.

Mechanism underlying treatment of ischemic stroke using acupuncture: transmission and regulation

The inflammatory response after cerebral ischemia/reperfusion is an important cause of neurological damage and repair. After cerebral ischemia/reperfusion, microglia are activated, and a large number of circulating inflammatory cells infiltrate the affected area. This leads to the secretion of inflammatory mediators and an inflammatory cascade that eventually causes secondary brain damage, including neuron necrosis, blood-brain barrier destruction, cerebral edema, and an oxidative stress response. Activation of inflammatory signaling pathways plays a key role in the pathological process of ischemic stroke. Increasing evidence suggests that acupuncture can reduce the inflammatory response after cerebral ischemia/reperfusion and promote repair of the injured nervous system. Acupuncture can not only inhibit the activation and infiltration of inflammatory cells, but can also regulate the expression of inflammation-related cytokines, balance the effects of pro-inflammatory and anti-inflammatory factors, and interfere with inflammatory signaling pathways. Therefore, it is important to study the transmission and regulatory mechanism of inflammatory signaling pathways after acupuncture treatment for cerebral ischemia/reperfusion injury to provide a theoretical basis for clinical treatment of this type of injury using acupuncture. Our review summarizes the overall conditions of inflammatory cells, mediators, and pathways after cerebral ischemia/reperfusion, and discusses the possible synergistic intervention of acupuncture in the inflammatory signaling pathway network to provide a foundation to explore the multiple molecular mechanisms by which acupuncture promotes nerve function restoration.

Uric Acid Neuroprotection Associated to IL-6/STAT3 Signaling Pathway Activation in Rat Ischemic Stroke

Despite the promising neuroprotective effects of uric acid (UA) in acute ischemic stroke, the seemingly pleiotropic underlying mechanisms are not completely understood. Recent evidence points to transcription factors as UA targets. To gain insight into the UA mechanism of action, we investigated its effects on pertinent biomarkers for the most relevant features of ischemic stroke pathophysiology: (1) oxidative stress (antioxidant enzyme mRNAs and MDA), (2) neuroinflammation (cytokine and Socs3 mRNAs, STAT3, NF-κB p65, and reactive microglia), (3) brain swelling (Vegfa, Mmp9, and Timp1 mRNAs), and (4) apoptotic cell death (Bcl-2, Bax, caspase-3, and TUNEL-positive cells). Adult male Wistar rats underwent intraluminal filament transient middle cerebral artery occlusion (tMCAO) and received UA (16 mg/kg) or vehicle (Locke's buffer) i.v. at 20 min reperfusion. The outcome measures were neurofunctional deficit, infarct, and edema. UA treatment reduced cortical infarct and brain edema, as well as neurofunctional impairment. In brain cortex, increased UA: (1) reduced tMCAO-induced increases in Vegfa and Mmp9/Timp1 ratio expressions; (2) induced Sod2 and Cat expressions and reduced MDA levels; (3) induced Il6 expression, upregulated STAT3 and NF-κB p65 phosphorylation, induced Socs3 expression, and inhibited microglia activation; and (4) ameliorated the Bax/Bcl-2 ratio and induced a reduction in caspase-3 cleavage as well as in TUNEL-positive cell counts. In conclusion, the mechanism for morphological and functional neuroprotection by UA in ischemic stroke is multifaceted, since it is associated to activation of the IL-6/STAT3 pathway, attenuation of edematogenic VEGF-A/MMP-9 signaling, and modulation of relevant mediators of oxidative stress, neuroinflammation, and apoptotic cell death.

Neuroprotective potential of imatinib in global ischemia-reperfusion-induced cerebral injury: possible role of Janus-activated kinase 2/signal transducer and activator of transcription 3 and connexin 43

The present study was aimed to explore the neuroprotective role of imatinib in global ischemia-reperfusion-induced cerebral injury along with possible mechanisms. Global ischemia was induced in mice by bilateral carotid artery occlusion for 20 min, which was followed by reperfusion for 24 h by restoring the blood flow to the brain. The extent of cerebral injury was assessed after 24 h of global ischemia by measuring the locomotor activity (actophotometer test), motor coordination (inclined beam walking test), neurological severity score, learning and memory (object recognition test) and cerebral infarction (triphenyl tetrazolium chloride stain). Ischemia-reperfusion injury produced significant cerebral infarction, impaired the behavioral parameters and decreased the expression of connexin 43 and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in the brain. A single dose administration of imatinib (20 and 40 mg/kg) attenuated ischemia-reperfusion-induced behavioral deficits and the extent of cerebral infarction along with the restoration of connexin 43 and p-STAT3 levels. However, administration of AG490, a selective Janus-activated kinase 2 (JAK2)/STAT3 inhibitor, abolished the neuroprotective actions of imatinib and decreased the expression of connexin 43 and p-STAT3. It is concluded that imatinib has the potential of attenuating global ischemia-reperfusion-induced cerebral injury, which may be possibly attributed to activation of JAK2/STAT3 signaling pathway along with the increase in the expression of connexin 43.

Molecular Biology of Atherosclerotic Ischemic Strokes

Among the causes of global death and disability, ischemic stroke (also known as cerebral ischemia) plays a pivotal role, by determining the highest number of worldwide mortality, behind cardiomyopathies, affecting 30 million people. The etiopathogenetic burden of a cerebrovascular accident could be brain ischemia (~80%) or intracranial hemorrhage (~20%). The most common site when ischemia occurs is the one is perfused by middle cerebral arteries. Worse prognosis and disablement consequent to brain damage occur in elderly patients or affected by neurological impairment, hypertension, dyslipidemia, and diabetes. Since, in the coming years, estimates predict an exponential increase of people who have diabetes, the disease mentioned above constitutes together with stroke a severe social and economic burden. In diabetic patients after an ischemic stroke, an exorbitant activation of inflammatory molecular pathways and ongoing inflammation is responsible for more severe brain injury and impairment, promoting the advancement of ischemic stroke and diabetes. Considering that the ominous prognosis of ischemic brain damage could by partially clarified by way of already known risk factors the auspice would be modifying poor outcome in the post-stroke phase detecting novel biomolecules associated with poor prognosis and targeting them for revolutionary therapeutic strategies.

Modulatory Effect of Myokines on Reactive Oxygen Species in Ischemia/Reperfusion

There is a growing body of evidence showing the importance of physical activity against acute ischemic events in various organs. Ischemia/reperfusion injury (I/R) is characterized by tissue damage as a result of restriction and subsequent restoration of blood supply to an organ. Oxidative stress due to increased reactive oxygen species formation and/or insufficient antioxidant defense is considered to play an important role in I/R. Physical activity not only decreases the general risk factors for ischemia but also confers direct anti-ischemic protection via myokine production. Myokines are skeletal muscle-derived cytokines, representing multifunctional communication channels between the contracting skeletal muscle and other organs through an endocrine manner. In this review, we discuss the most prominent members of the myokines (i.e., brain-derived neurotrophic factor (BDNF), cathepsin B, decorin, fibroblast growth factors-2 and -21, follistatin, follistatin-like, insulin-like growth factor-1; interleukin-6, interleukin-7, interleukin-15, irisin, leukemia inhibitory factor, meteorin-like, myonectin, musclin, myostatin, and osteoglycin) with a particular interest in their potential influence on reactive oxygen and nitrogen species formation or antioxidant capacity. A better understanding of the mechanism of action of myokines and particularly their participation in the regulation of oxidative stress may widen their possible therapeutic use and, thereby, may support the fight against I/R.

Preconditioning Strategies to Enhance Neural Stem Cell-Based Therapy for Ischemic Stroke

Transplantation of neural stem cells (NSCs) has been proposed as an alternative novel therapy to replace damaged neural circuitry after ischemic stroke onset. Nonetheless, albeit the potential of these cells for stroke therapy, many critical challenges are yet to be overcome to reach clinical applications. The major limitation of the NSC-based therapy is its inability to retain most of the donor stem cells after grafting into an ischemic brain area which is lacking of essential oxygen and nutrients for the survival of transplanted cells. Low cell survival rate limits the capacity of NSCs to repair the injured area and this poses a much more difficult challenge to the NSC-based therapy for ischemic stroke. In order to enhance the survival of transplanted cells, several stem cell culture preconditioning strategies have been employed. For ischemic diseases, hypoxic preconditioning is the most commonly applied strategy since the last few decades. Now, the preconditioning strategies have been developed and expanded enormously throughout years of efforts. This review systematically presented studies searched from PubMed, ScienceDirect, Web of Science, Scopus and the Google Scholar database up to 31 March 2020 based on search words containing the following terms: "precondition" or "pretreatment" and "neural stem cell" and "ischemic stroke". The searched data comprehensively reported seven major NSC preconditioning strategies including hypoxic condition, small drug molecules such as minocycline, doxycycline, interleukin-6, adjudin, sodium butyrate and nicorandil, as well as electrical stimulation using conductive polymer for ischemic stroke treatment. We discussed therapeutic benefits gained from these preconditioned NSC for in vitro and in vivo stroke studies and the detailed insights of the mechanisms underlying these preconditioning approaches. Nonetheless, we noticed that there was a scarcity of evidence on the efficacy of these preconditioned NSCs in human clinical studies, therefore, it is still too early to draw a definitive conclusion on the efficacy and safety of this active compound for patient usage. Thus, we suggest for more in-depth clinical investigations of this cell-based therapy to develop into more conscientious and judicious evidence-based therapy for clinical application in the future.

Associations between serum L-arginine and ficolins in the early phase of acute ischemic stroke - A pilot study

INTRODUCTION

Activation of both the L-arginine and the lectin pathway contributes to the pathophysiology and the outcome of acute ischemic stroke (AIS). However, the interplay between the two systems has not yet been examined.

METHODS

A total of 44 patients with AIS were recruited into this study. Serial measurement of serum L-arginine, asymmetric and symmetric dimethylarginine (ADMA, SDMA), and hsCRP, ficolin-2, ficolin-3, MAP-1, MASP-3 and mannose-binding lectin (MBL) were analyzed within 6 h after onset of stroke and 72 h later. Outcomes were assessed as National Institutes of Health Stroke Scale (NIHSS) worsening by 24 h, poststroke infection, and death by 1 month.

RESULTS

In the hyperacute stage of AIS, ficolin-3, MAP-1 and MBL were positively correlated with L-arginine within 6 h after onset of symptoms (p<0.05 respectively). Significantly lower ficolin-3 and MASP-3 levels were found at 72 h in patients, who developed post-stroke infection after day 4, when compared to patients without post-stroke infections (p=0.03 and p=0.009). At 72 hours, ficolin-3 levels negatively correlated with S100B (p=0.01). Ficolin-3 at 72 post-stroke hours remained an independent predictor of post-stroke infection, while only hsCRP was an independent predictor of 30-day mortality.

CONCLUSION

Early consumption of ficolin-3 is associated with complications such as post-stroke infections. In the hyperacute phase of AIS, the positive correlation between ficolins and the NO donor L-arginine may reflect the protective role of L-arginine presumably by improving the cerebral microcirculation in a prothrombotic environment induced by complement activation.

RNA-seq analysis and compound screening highlight multiple signalling pathways regulating secondary cell death after acute CNS injury in vivo

Understanding the molecular mechanisms that regulate secondary cell death after acute central nervous system (CNS) injury is critical for the development of effective neuroprotective drugs. Previous research has shown that neurotoxic processes including excitotoxicity, oxidative stress and neuroinflammation can cause secondary cell death. Nevertheless, clinical trials targeting these processes have been largely unsuccessful, suggesting that the signalling pathways underlying secondary cell death remain incompletely understood. Due to their suitability for live imaging and their amenability to genetic and pharmacological manipulation, larval zebrafish provide an ideal platform for studying the regulation of secondary cell death in vivo Here, we use RNA-seq gene expression profiling and compound screening to identify signalling pathways that regulate secondary cell death after acute neural injury in larval zebrafish. RNA-seq analysis of genes upregulated in cephalic mpeg1⁺ macrophage-lineage cells isolated from mpeg1:GFP transgenic larvae after neural injury suggested an involvement of cytokine and polyamine signalling in secondary cell death. Furthermore, screening a library of FDA approved compounds indicated roles for GABA, serotonin and dopamine signalling. Overall, our results highlight multiple signalling pathways that regulate secondary cell death in vivo, and thus provide a starting point for the development of novel neuroprotective treatments for patients with CNS injury.This article has an associated First Person interview with the two first authors of the paper.

EPA is Cardioprotective in Male Rats Subjected to Sepsis, but ALA Is Not Beneficial

It has been proven that dietary eicosapentaenoic acid (C20:5 n-3 or EPA) protects the heart against the deleterious effects of sepsis in female rats. We do not know if this is the case for male rodents. In this case, the efficiency of other n-3 polyunsaturated fatty acids (PUFAs) remains to be determined in both female and male rats. This study aimed at (i) determining whether dietary EPA is cardioprotective in septic male rats; (ii) evaluating the influence of dietary α-linolenic (C18:3 n-3 or ALA) on cardiac function during this pathology; and (iii) finding out the physiological and molecular mechanisms responsible for the observed effects. Sixty male rats were divided into three dietary groups. The animals were fed a diet deficient in n-3 PUFAs (DEF group), a diet enriched with ALA (ALA group) or a diet fortified with EPA (EPA group) for 6 weeks. Thereafter, each group was subdivided into 2 subgroups, one being subjected to cecal ligation and puncture (CLP) and the other undergoing a fictive surgery. Cardiac function was determined in vivo and ex vivo. Several parameters related to the inflammation process and oxidative stress were determined. Finally, the fatty acid compositions of circulating lipids and cardiac phospholipids were evaluated. The results of the ex vivo situation indicated that sepsis triggered cardiac damage in the DEF group. Conversely, the ex vivo data indicated that dietary ALA and EPA were cardioprotective by resolving the inflammation process and decreasing the oxidative stress. However, the measurements of the cardiac function in the in vivo situation modulated these conclusions. Indeed, in the in vivo situation, sepsis deteriorated cardiac mechanical activity in the ALA group. This was suspected to be due to a restricted coronary flow which was related to a lack of cyclooxygenase substrates in membrane phospholipids. Finally, only EPA proved to be beneficial in sepsis. Its action necessitates both resolution of inflammation and increased coronary perfusion. In that sense, dietary ALA, which does not allow the accumulation of vasodilator precursors in membrane lipids, cannot be protective during the pathology.

Glial Cells: Role of the Immune Response in Ischemic Stroke

Ischemic stroke, which accounts for 75-80% of all strokes, is the predominant cause of morbidity and mortality worldwide. The post-stroke immune response has recently emerged as a new breakthrough target in the treatment strategy for ischemic stroke. Glial cells, including microglia, astrocytes, and oligodendrocytes, are the primary components of the peri-infarct environment in the central nervous system (CNS) and have been implicated in post-stroke immune regulation. However, increasing evidence suggests that glial cells exert beneficial and detrimental effects during ischemic stroke. Microglia, which survey CNS homeostasis and regulate innate immune responses, are rapidly activated after ischemic stroke. Activated microglia release inflammatory cytokines that induce neuronal tissue injury. By contrast, anti-inflammatory cytokines and neurotrophic factors secreted by alternatively activated microglia are beneficial for recovery after ischemic stroke. Astrocyte activation and reactive gliosis in ischemic stroke contribute to limiting brain injury and re-establishing CNS homeostasis. However, glial scarring hinders neuronal reconnection and extension. Neuroinflammation affects the demyelination and remyelination of oligodendrocytes. Myelin-associated antigens released from oligodendrocytes activate peripheral T cells, thereby resulting in the autoimmune response. Oligodendrocyte precursor cells, which can differentiate into oligodendrocytes, follow an ischemic stroke and may result in functional recovery. Herein, we discuss the mechanisms of post-stroke immune regulation mediated by glial cells and the interaction between glial cells and neurons. In addition, we describe the potential roles of various glial cells at different stages of ischemic stroke and discuss future intervention targets.

Dectin-1/Syk signaling triggers neuroinflammation after ischemic stroke in mice

Background

Dendritic cell-associated C-type lectin-1 (Dectin-1) receptor has been reported to be involved in neuroinflammation in Alzheimer’s disease and traumatic brain injury. The present study was designed to investigate the role of Dectin-1 and its downstream target spleen tyrosine kinase (Syk) in early brain injury after ischemic stroke using a focal cortex ischemic stroke model.

Methods

Adult male C57BL/6 J mice were subjected to a cerebral focal ischemia model of ischemic stroke. The neurological score, adhesive removal test, and foot-fault test were evaluated on days 1, 3, 5, and 7 after ischemic stroke. Dectin-1, Syk, phosphorylated (p)-Syk, tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) expression was analyzed via western blotting in ischemic brain tissue after ischemic stroke and in BV2 microglial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury in vitro. The brain infarct volume and Iba1-positive cells were evaluated using Nissl’s and immunofluorescence staining, respectively. The Dectin-1 antagonist laminarin (LAM) and a selective inhibitor of Syk phosphorylation (piceatannol; PIC) were used for the intervention.

Results

Dectin-1, Syk, and p-Syk expression was significantly enhanced on days 3, 5, and 7 and peaked on day 3 after ischemic stroke. The Dectin-1 antagonist LAM or Syk inhibitor PIC decreased the number of Iba1-positive cells and TNF-α and iNOS expression, decreased the brain infarct volume, and improved neurological functions on day 3 after ischemic stroke. In addition, the in vitro data revealed that Dectin-1, Syk, and p-Syk expression was increased following the 3-h OGD and 0, 3, and 6 h of reperfusion in BV2 microglial cells. LAM and PIC also decreased TNF-α and iNOS expression 3 h after OGD/R induction.

Conclusion

Dectin-1/Syk signaling plays a crucial role in inflammatory activation after ischemic stroke, and further investigation of Dectin-1/Syk signaling in stroke is warranted.

Application of the Zebrafish Traumatic Brain Injury Model in Assessing Cerebral Inflammation

Traumatic brain injury (TBI) is a major public and socioeconomic problem throughout the world. The establishment of an effective and cost-effective TBI model for developing new therapeutic agents is challenging. Microglia are considered the resident macrophages of the central nervous system (CNS) that normally do not enter the brain. As the primary mediators of the innate immune response in the CNS, microglia play a critical role in neuroinflammation and secondary injury after TBI. In this study, we established an in vivo TBI zebrafish model using Tg(coro1a:EGFP) line where the green fluorescent protein-labeled microglia were present. We demonstrated that microglia accumulated rapidly in response to neuronal injuries. To clear away injured neurons and restore the CNS homeostasis, activated microglia secreted two types of functional cytokines, including pro-inflammatory interleukins (IL) of IL-1β and IL-6 and anti-inflammatory factors of IL-4 and IL-10 in the lesioned larvae. Cytidine 5'-Diphosphocholine (CDP-choline), as an effective and clinical neuroprotective drug, could further activate microglia, expressing high levels of il-1β, il-6, il-4, and il-10 in the TBI model. Moreover, CDP-choline reduced neuronal apoptosis and promoted neuronal proliferation around the lesioned site. Based on these results, the TBI model established in this study represents a suitable model for developing new therapeutic agents for CNS-associated diseases.

Azithromycin Affords Neuroprotection in Rat Undergone Transient Focal Cerebral Ischemia

Repurposing existing drugs represents a promising approach for successful development of acute stroke therapies. In this context, the macrolide antibiotic azithromycin has been shown to exert neuroprotection in mice due to its immunomodulatory properties. Here, we have demonstrated that acute administration of a single dose of azithromycin upon reperfusion produces a dose-dependent (ED₅₀ = 1.40 mg/kg; 95% CI = 0.48-4.03) reduction of ischemic brain damage measured 22 h after transient (2 h) middle cerebral artery occlusion (MCAo) in adult male rats. Neuroprotection by azithromycin (150 mg/kg, i.p., upon reperfusion) was associated with a significant elevation of signal transducer and activator of transcription 3 (STAT3) phosphorylation in astrocytes and neurons of the peri-ischemic motor cortex as detected after 2 and 22 h of reperfusion. By contrast, in the core region of the striatum, drug administration resulted in a dramatic elevation of STAT3 phosphorylation only after 22 h of reperfusion, being the signal mainly ascribed to infiltrating leukocytes displaying an M2 phenotype. These early molecular events were associated with a long-lasting neuroprotection, since a single dose of azithromycin reduced brain infarct damage and neurological deficit measured up to 7 days of reperfusion. These data, together with the evidence that azithromycin was effective in a clinically relevant time-window (i.e., when administered after 4.5 h of MCAo), provide robust preclinical evidence to support the importance of developing azithromycin as an effective acute therapy for ischemic stroke.

Biomarkers for ischemic stroke subtypes: A protein-protein interaction analysis

According to the Trial of Org 10172 in Acute Stroke Treatment, ischemic stroke is classified into five subtypes. However, the predictive biomarkers of ischemic stroke subtypes are still largely unknown. The utmost objective of this study is to map, construct and analyze protein-protein interaction (PPI) networks for all subtypes of ischemic stroke, and to suggest the predominant biological pathways for each subtypes. Through 6285 protein data retrieved from PolySearch2 and STRING database, the first PPI networks for all subtypes of ischemic stroke were constructed. Notably, F2 and PLG were identified as the critical proteins for large artery atherosclerosis (LAA), lacunar, cardioembolic, stroke of other determined etiology (SOE) and stroke of undetermined etiology (SUE). Gene ontology and DAVID analysis revealed that GO:0030193 regulation of blood coagulation and GO:0051917 regulation of fibrinolysis were the important functional clusters for all the subtypes. In addition, inflammatory pathway was the key etiology for LAA and lacunar, while FOS and JAK2/STAT3 signaling pathways might contribute to cardioembolic stroke. Due to many risk factors associated with SOE and SUE, the precise etiology for these two subtypes remained to be concluded.

Human orbital adipose tissue-derived mesenchymal stem cells possess neuroectodermal differentiation and repair ability

Mesenchymal stem cells (MSCs) are used extensively in cell therapy for repair and regeneration of several organs and tissues. Cell therapy is a valuable option to treat neurodegenerative diseases and MSCs have been shown to improve neuronal function through direct differentiation or secretion of neurotrophic factors. In the present study, we isolated and characterized stem cells from medial and central orbital adipose tissue and found that they could be grown in a monolayer culture. The orbital adipose tissue-derived cells were identical to bone marrow-derived MSCs in their cell surface marker expression, gene expression and multilineage differentiation abilities. The orbital adipose-derived MSCs (OAMSCs) express several neurotrophic factors, possess neuroectodermal differentiation ability and secreted factors from OAMSCs abrogated neuronal cell damage induced by oxidative stress. Thus, OAMSCs might be a valuable cell source for treatment of neurological diseases and to reverse oxidative damage in the neuronal cells.

Fas-ligand and interleukin-6 in the cerebrospinal fluid are early predictors of hypoxic-ischemic encephalopathy and long-term outcomes after birth asphyxia in term infants

BACKGROUND

Cerebral ischemia generates neuroinflammation that can induce neural cell death. This cohort study assessed whether Fas-ligand (FasL) and interleukin (IL)-6 levels in the cerebrospinal fluid (CSF) after hypoxic-ischemic encephalopathy (HIE) can serve as biomarkers of hypoxic brain injury in neonates.

METHODS

Term infants (> 37-week gestational age) who were admitted to the neonatal intensive care unit of Karolinska University Hospital in years 2002 to 2004 with perinatal asphyxia were enrolled prospectively. Control infants without brain pathology underwent lumbar puncture for suspected infection. FasL and IL-6 levels were measured in the CSF, by enzyme-linked immunosorbent assays. All patients underwent neurological assessment at 18 months. HIE was classified as mild, moderate, or severe (HIE I-III). Adverse neurological outcome at 18 months was defined as a mental developmental index < 85, deafness, blindness, cerebral palsy, or seizure disorder.

RESULTS

Of the 44 HIE patients, 14, 16, and 14 had HIE-I, HIE-II, and HIE-III, respectively. HIE-II and HIE-III patients had higher FasL and IL-6 levels than HIE-I patients and the 20 controls (all p < 0.0001). Patients with adverse outcomes had higher FasL and IL-6 levels than patients with normal outcomes and controls (both p < 0.0001). On receiver-operator curve analyses, FasL and IL-6 (alone and together) were highly predictive of HIE grade and outcome (areas under the curve range 0.86-0.94) and showed high sensitivity (66.7-100%). These biomarkers performed better than cord blood pH (areas under the curve: HIE grade = 0.80, adverse outcomes = 0.86).

CONCLUSION

CSF biomarkers FasL and IL-6 predicted severity of encephalopathy and long-term outcomes in post-asphyxiated infants better than a standard biomarker.

Tb II-I, a Fraction Isolated from Tityus bahiensis Scorpion Venom, Alters Cytokines': Level and Induces Seizures When Intrahippocampally Injected in Rats

Scorpion venoms are composed of several substances with different pharmacological activities. Neurotoxins exert their effects by targeting ion channels resulting in toxic effects to mammals, insects and crustaceans. Tb II-I, a fraction isolated from Tityus bahiensis scorpion venom, was investigated for its ability to induce neurological and immune-inflammatory effects. Two putative &beta;-sodium channel toxins were identified in this fraction, Tb2 II and Tb 4, the latter having been completely sequenced by mass spectrometry. Male Wistar rats, stereotaxically implanted with intrahippocampal cannulas and electrodes, were injected with Tb II-I (2 &micro;g/2 &micro;L) via the intrahippocampal route. The behavior, electrographic activity and cellular integrity of the animals were analyzed and the intracerebral level of cytokines determined. Tb II-I injection induced seizures and damage in the hippocampus. These alterations were correlated with the changes in the level of the cytokines tumoral necrosis factor-&alpha; (TNF-&alpha;) and interleukin-6 (IL-6). Therefore, the binding of Tb II-I to its target in the central nervous system may induce inflammation resulting in neuropathological and behavioral alterations.

Effects of interleukin-6 and IL-6/AMPK signaling pathway on mitochondrial biogenesis and astrocytes viability under experimental septic condition

OBJECTIVE

Interleukin-6 (IL-6) is a neuromodulation factor with extensive and complex biological activities. IL-6 has been reported to activate AMPK, while AMPK regulates mitochondrial biogenesis and autophagy. The aim of this study was to investigate the role of IL-6 in mitochondrial biogenesis using astrocytes under experimental septic condition and examined how IL-6/AMPK signaling pathway affected this process.

METHODS

The primary cultures of cerebral cortical astrocytes were randomly allocated into six groups: control group, LPS+IFN-γ group, IL-6 group (LPS+IFN-γ+IL-6), C group (LPS+IFN-γ+IL-6+Compound C), siRNA group (LPS+IFN-γ+IL-6+IL-6R siRNA) and siRNA+C group (LPS+IFN-γ+IL-6+IL-6R siRNA+ Compound C). All groups were stimulated for 6 h. Cytokines and reactive oxygen species (ROS) analyses, detection of adenosine triphosphate (ATP), mtDNA content and cell viability, evaluation of the mitochondrial ultrastructure and volume density, western blots of proteins associated with mitochondrial biogenesis and phospho-adenosine monophosphate activated protein kinase (p-AMPK) were performed respectively.

RESULTS

Compared with LPS+IFN-γ group, IL-6 group had milder ultrastructural damage of mitochondria, higher mtDNA content and mitochondrial volume density, higher expression of proteins associated with mitochondrial biogenesis (PGC-1α, NRF-1 and TFAM) and p-AMPK, and thus higher cell viability, whereas blocking IL-6/AMPK signaling pathway, the protective effect of IL-6 has been diminished, compared with IL-6 group.

CONCLUSION

IL-6 enhances mitochondrial biogenesis in astrocytes under experimental septic condition through IL-6/AMPK signaling pathway.

STAT3 precedes HIF1α transcriptional responses to oxygen and oxygen and glucose deprivation in human brain pericytes

Brain pericytes are important to maintain vascular integrity of the neurovascular unit under both physiological and ischemic conditions. Ischemic stroke is known to induce an inflammatory and hypoxic response due to the lack of oxygen and glucose in the brain tissue. How this early response to ischemia is molecularly regulated in pericytes is largely unknown and may be of importance for future therapeutic targets. Here we evaluate the transcriptional responses in in vitro cultured human brain pericytes after oxygen and/or glucose deprivation. Hypoxia has been widely known to stabilise the transcription factor hypoxia inducible factor 1-alpha (HIF1α) and mediate the induction of hypoxic transcriptional programs after ischemia. However, we find that the transcription factors Jun Proto-Oncogene (c-JUN), Nuclear Factor Of Kappa Light Polypeptide Gene Enhancer In B-Cells (NFκB) and signal transducer and activator of transcription 3 (STAT3) bind genes regulated after 2hours (hs) of omitted glucose and oxygen before HIF1α. Potent HIF1α responses require 6hs of hypoxia to substantiate transcriptional regulation comparable to either c-JUN or STAT3. Phosphorylated STAT3 protein is at its highest after 5 min of oxygen and glucose (OGD) deprivation, whereas maximum HIF1α stabilisation requires 120 min. We show that STAT3 regulates angiogenic and metabolic pathways before HIF1α, suggesting that HIF1α is not the initiating trans-acting factor in the response of pericytes to ischemia.

Systematic studies on the in vivo substance basis and the pharmacological mechanism of Acanthopanax Senticosus Harms leaves by UPLC-Q-TOF-MS coupled with a target-network method

The leaves of Acanthopanax Senticosus Harms (ASL) can be used as a food ingredient and also as raw materials for making tea and wine.

Beneficial potential of intravenously administered IL-6 in improving outcome after murine experimental stroke

Interleukin-6 (IL-6) is a pleiotropic cytokine with neuroprotective properties. Still, the therapeutic potential of IL-6 after experimental stroke has not yet been investigated in a clinically relevant way. Here, we investigated the therapeutic use of intravenously administered IL-6 and the soluble IL-6 receptor (sIL-6R) alone or in combination, early after permanent middle cerebral artery occlusion (pMCAo) in mice. IL-6 did not affect the infarct volume in C57BL/6 mice, at neither 24 nor 72h after pMCAo but reduced the infarct volume in IL-6 knockout mice at 24h after pMCAo. Assessment of post-stroke behavior showed an improved grip strength after a single IL-6 injection and also improved rotarod endurance after two injections, in C57BL/6 mice at 24h. An improved grip strength and a better preservation of sensory functions was also observed in IL-6 treated IL-6 knockout mice 24h after pMCAo. Co-administration of IL-6 and sIL-6R increased the infarct volume, the number of infiltrating polymorphonuclear leukocytes and impaired the rotarod endurance of C57BL/6 mice 24h after pMCAo. IL-6 administration to naïve C57BL/6 mice lead after 45min to increased plasma-levels of CXCL1 and IL-10, whereas IL-6 administration to C57BL/6 mice lead to a reduction in the ischemia-induced increase in IL-6 and CXCL1 at both mRNA and protein level in brain, and of IL-6 and CXCL1 in serum. We also investigated the expression of IL-6 and IL-6R after pMCAo and found that cortical neurons upregulated IL-6 mRNA and protein, and upregulated IL-6R after pMCAo. In conclusion, the results show a complex but potentially beneficial effect of intravenously administered IL-6 in experimental stroke.

F. CARACTERIZACIÓN TEMPORO-ESPACIAL DEL PATRÓN DE MARCHA EN ROEDORES COMO MODELO ANIMAL DE LESIÓN CEREBRAL CEREBROVASCULAR

En la investigación sobre movimiento, la experimentación animal ha proporcionado fundamentación científica para la investigación clínica, mejorando procedimientos diagnósticos y de rehabilitación. Lesiones cerebrales en roedores pueden ser usadas para modelar síntomas locomotores, sensoriales y/o cognitivos. Con el propósito de determinar la funcionalidad locomotriz y sensorial en roedores, se han propuesto varios métodos de evaluación y pronóstico clínico para identificar y evaluar adaptaciones estructurales y mecanismos de neuro-recuperación. Esto ha permitido que métodos de intervención terapéutica, como el ejercicio físico, sean utilizados para restaurar funciones sensitivo-motoras y cognitivas en roedores y humanos. La extrapolación (translación) de los resultados de investigaciones en ciencias básicas a áreas clínicas supone la continua cooperación y retroalimentación entre investigadores y profesionales de la salud, favoreciendo la formulación de intervenciones terapéuticas más eficaces basadas en resultados obtenidos de la experimentación animal. El objetivo de esta revisión es exponer las principales deficiencias motoras y los métodos empleados para determinar la dificultad motriz en la marcha en roedores con lesión cerebrovascular, para lo cual se realizó una revisión de literatura, sobre términos definidos (MeSH), en las bases de datos PsychINFO, Medline y Web of Science, entre enero de 2000 y enero de 2017. Se excluyeron artículos de carácter cualitativo o narrativo, sin revisión por pares, disertaciones, tesis o trabajos de grado y resúmenes de conferencias. Se revisan algunas manifestaciones clínicas, su efecto en la locomotricidad en roedores, algunas metodologías usadas para generar lesiones y para estudiar la función motriz, los principales métodos de medición y algunos aspectos translacionales. 

Inhibiting HMGB1 Reduces Cerebral Ischemia Reperfusion Injury in Diabetic Mice

High mobility group box1 (HMGB1) promotes inflammatory injury, and accumulating evidence suggests that it plays a key role in brain ischemia reperfusion (I/R), as well as the development of diabetes mellitus (DM). The purpose of this study was to investigate whether HMGB1 plays a role in brain I/R in a DM mouse model. Diabetes mellitus was induced by a high-calorie diet and streptozotocin treatment, and cerebral ischemia was induced by middle cerebral artery occlusion. We examined HMGB1 levels following cerebral I/R injury in DM and non-DM mice and evaluated the influence of altered HMGB1 levels on the severity of cerebral injury. Serum HMGB1 levels and the inflammatory factors IL-1β, IL-6, and inflammation-related enzyme iNOS were significantly elevated in DM mice with brain I/R compared with non-DM mice with brain I/R. Blocking HMGB1 function by intraperitoneal injection of anti-HMGB1 neutralizing antibodies reversed the inflammatory response and the extent of brain damage, suggesting that HMGB1 plays an important role in cerebral ischemic stroke in diabetic mice.