The role of interleukin 1 in acute neurodegeneration and stroke: pathophysiological and therapeutic implications

Additive aluminum as a cause of induced immunoexcitoxicity resulting in neurodevelopmental and neurodegenerative disorders: A biochemical, pathophysiological, and pharmacological analysis

Much has been learned about the neurotoxicity of aluminum over the past several decades in terms of its ability to disrupt cellular function, result in slow accumulation, and the difficulty of its removal from cells. Newer evidence suggests a central pathophysiological mechanism may be responsible for much of the toxicity of aluminum and aluminofluoride compounds on the brain and spinal cord. This mechanism involves activation of the brain's innate immune system, primarily the microglia, astrocytes, and macrophages, with a release of neurotoxic concentrations of excitotoxins and proinflammatory cytokines, chemokines, and immune mediators. Many studies suggest that excitotoxicity plays a significant role in the neurotoxic action of several metals, including aluminum. Recently, researchers have found that while most of the chronic pathology involved in the observed neurodegenerative effects of these metals are secondary to prolonged inflammation, it is the enhancement of excitotoxicity by the immune mediators that are responsible for most of the metal's toxicity. This enhancement occurs through a crosstalk between cytokines and glutamate-related mechanisms. The author coined the name immunoexcitotoxicity to describe this process. This paper reviews the evidence linking immunoexcitotoxicity to aluminum's neurotoxic effects and that a slow accumulation of aluminum may be the cause of neurodevelopmental defects as well as neurodegeneration in the adult.

Astrocyte-targeted siRNA delivery by adenosine-functionalized LNP in mouse TBI model

Traumatic brain injury (TBI) induces pro-inflammatory polarization of astrocytes and causes secondary disruption of the blood-brain barrier (BBB) and brain damage. Herein, we report a successful astrocyte-targeted delivery of small interfering RNA (siRNA) by ligand functionalized lipid nanoparticles (LNPs) formulated from adenosine-conjugated lipids and a novel ionizable lipid (denoted by Ad4 LNPs). Systemic administration of Ad4 LNPs carrying siRNA against TLR4 to the mice TBI model resulted in the specific internalization of the LNPs by astrocytes in the vicinity of damaged brain tissue. A substantial knockdown of TLR4 at both mRNA and protein levels in the brain was observed, which led to a significant decrease of key pro-inflammatory cytokines and an increase of key anti-inflammatory cytokines in serum. Dye leakage measurement suggested that the Ad4-LNP-mediated knockdown of TLR4 attenuated the TBI-induced BBB disruption. Together, our data suggest that Ad4 LNP is a promising vehicle for astrocyte-specific delivery of nucleic acid therapeutics.

Assessment of interleukin 1 receptor antagonist (IL-1RA) levels in children with and without community acquired pneumonia: a hospital based case-control study

The primary objective was to compare serum interleukin-1 receptor antagonist (IL-1RA) levels in cases of community acquired pneumonia (CAP) and healthy age-gender-matched controls. The secondary objective was to compare serum IL-1RA levels in cases which were positive or negative for Streptococcus pneumoniae in the blood by real-time-polymerase chain reaction (RT-PCR). Hospitalized children with World Health Organization defined CAP, aged 2-59 months, were included as cases. Healthy controls were recruited from the immunization clinic of the hospital. Enzyme-linked immunosorbent assay (ELISA) test was used to detect serum IL-1RA levels. Identification of S.pneumoniae in blood was done by RT-PCR. From October 2019 to October 2021, 330 cases (123, 37.27% female) and 330 controls (151, 45.75% females) were recruited. Mean serum IL-1RA levels (ng/ml) were 1.36 ± 0.95 in cases and 0.25 ± 0.25 in controls (p < 0.001). Within cases, serum IL-1RA levels were significantly higher in those whose RT-PCR was positive for S.pneumoniae. Thus serum IL-1RA levels may be evaluated as a surrogate marker of S.pneumoniae in future studies.

Chuanzhitongluo regulates microglia polarization and inflammatory response in acute ischemic stroke

BACKGROUND AND PURPOSE

Chuanzhitongluo (CZTL), a traditional Chinese medicine mixture, is used in the recovery period of acute ischemic stroke (AIS), and effectively improves the prognosis of AIS patients. This study aims to evaluate whether CZTL regulates microglia polarization and inflammatory response to reduce brain damage in the acute phase of AIS.

METHODS

A mouse model of AIS was prepared by the photochemical method. Cerebral infarct volume was detected by 2,3,5-Triphenyltetrazolium chloride (TTC) staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was used to assess neuronal apoptosis. Gene expression profile change was explored by Gene chip. Inflammatory factors were analyzed by Protein microarray. The Immunofluorescence double-labeling assay was executed to elucidate the effects of CD16⁺ / Iba-1⁺ and CD206⁺ / Iba-1⁺ in the peripheral area of cerebral ischemia.

RESULTS

Results revealed that CZTL treatment alleviated the neurological impairment, reduced cerebral infarct volume, and inhibited neuronal apoptosis. CZTL altered gene expression profiles, which indicate that CZTL may be involved in regulating neuroinflammation. CZTL restrained inflammatory responses by down-regulated pro-inflammatory cytokines expression and enhanced anti-inflammatory cytokines level. Further experiments demonstrated that CZTL inhibited the activation of NLRP3 inflammasome, which decreasing the inflammatory response. In addition, CZTL promoted the transformation of microglia from M1 to M2 phenotype.

CONCLUSIONS

These results indicate that CZTL alleviates neuroinflammation and brain damage after AIS in mice, which may be mediated by modulating microglia polarization.

Relationships Among Gut Microbiota, Ischemic Stroke and Its Risk Factors: Based on Research Evidence

Stroke is a highly lethal disease and disabling illness while ischemic stroke accounts for the majority of stroke. It has been found that inflammation plays a key role in the initiation and progression of stroke, and atherosclerotic plaque rupture is considered to be the leading cause of ischemic stroke. Furthermore, chronic inflammatory diseases, such as obesity, type 2 diabetes mellitus (T2DM) and hypertension, are also considered as the high-risk factors for stroke. Recently, the topic on how gut microbiota affects human health has aroused great concern. The initiation and progression of ischemic stroke has been found to have close relation with gut microbiota dysbiosis. Hence, this manuscript briefly summarizes the roles of gut microbiota in ischemic stroke and its related risk factors, and the practicability of preventing and alleviating ischemic stroke by reconstructing gut microbiota.

Survival analysis by inflammatory biomarkers in severely injured patients undergoing damage control resuscitation

BACKGROUND

Although early balanced blood product resuscitation has improved mortality after traumatic injury, many patients still suffer from inflammatory complications. The goal of this study was to identify inflammatory mediators associated with death and multiorgan system failure following severe injury after patients undergo blood product resuscitation.

METHODS

A retrospective secondary analysis of inflammatory markers from the Pragmatic Randomized Optimal Platelet and Plasma Ratios study was performed. Twenty-seven serum biomarkers were measured at 8 time points in the first 72 hours of care and were compared between survivors and nonsurvivors. Biomarkers with significant differences were further analyzed by adjudicated cause of 30-day mortality.

RESULTS

Biomarkers from 680 patients were analyzed. Seven key inflammatory markers (IL-1ra, IL-6, IL-8, IL-10, eotaxin, IP-10, and MCP-1) were further analyzed. These cytokines were also noted to have the highest hazard ratios of death. Stepwise selection was used for multivariate analysis of survival by time point. MCP-1 at 2 hours, eotaxin and IP-10 at 12 hours, eotaxin at 24 hours, and IP-10 at 72 hours were associated with all-cause mortality.

CONCLUSION

Early systemic inflammatory markers are associated with increased risk of mortality after traumatic injury. Future studies should use these biomarkers to prospectively calculate risks of morbidity and causes of mortality for all trauma patients.

Non-coding RNAs and their bioengineering applications for neurological diseases

Engineering of cellular biomolecules is an emerging landscape presenting creative therapeutic opportunities. Recently, several strategies such as biomimetic materials, drug-releasing scaffolds, stem cells, and dynamic culture systems have been developed to improve specific biological functions, however, have been confounded with fundamental and technical roadblocks. Rapidly emerging investigations on the bioengineering prospects of mammalian ribonucleic acid (RNA) is expected to result in significant biomedical advances. More specifically, the current trend focuses on devising non-coding (nc) RNAs as therapeutic candidates for complex neurological diseases. Given the pleiotropic and regulatory role, ncRNAs such as microRNAs and long non-coding RNAs are deemed as attractive therapeutic candidates. Currently, the list of non-coding RNAs in mammals is evolving, which presents the plethora of hidden possibilities including their scope in biomedicine. Herein, we critically review on the emerging repertoire of ncRNAs in neurological diseases such as Alzheimer’s disease, Parkinson’s disease, neuroinflammation and drug abuse disorders. Importantly, we present the advances in engineering of ncRNAs to improve their biocompatibility and therapeutic feasibility as well as provide key insights into the applications of bioengineered non-coding RNAs that are investigated for neurological diseases.

Oxidative stress-A direct bridge to central nervous system homeostatic dysfunction and Alzheimer's disease

Neurologists have highly observed a frequent increasing number of elderly patients with Alzheimer's disease (AD) without any relevant evidence of any genetic or known AD-linked predisposing factors in the past few years. Those patients are characterized by continuous and irreversible neuron cells loss along with declined cognitive functions. Numerous studies have suggested that the exaggerated release of reactive oxygen species (ROS) within the brain may develop late-onset neurodegenerative disorders, especially AD-neuroinflammatory type. However, the central nervous system is vitally linked with whole-brain chemical integrity and its related healthy state, the cascade by which ROS may result in AD's development has not been highly justified or even maintained. It is widely known that the brain consumes a vast amount of oxygen and is characterized by being rich in lipid polyunsaturated fatty acids content, explaining why it is a prone region to oxidative stress (OS) and ROS damage. The formed OS-AD cytoskeletal protein aggregates can be considered a main predisposing factor for amyloid-beta (Aβ) hallmarks precipitation. Herein, this review aims to provide a detailed information on how oxidative stress can play a pathogenic role in activating damage-associated molecular patterns (DAMPs)-related toll-like receptor-4 inflammatory (TLR-4) cascades resulting in the deposition of Aβ hallmarks in brain tissues ending with irreversible cognitive dysfunction. It also explains how microglia can be activated via ROS, which may significantly release several pro-inflammatory cascades ending with general brain atrophy. Furthermore, different types of suggested antioxidant therapies will be discussed to combat AD-related pathological disorders and hallmarks.

Modulation of Neural Networks by Interleukin-1

Interleukin-1 (IL-1) is an inflammatory cytokine that has been shown to modulate neuronal signaling in homeostasis and diseases. In homeostasis, IL-1 regulates sleep and memory formation, whereas in diseases, IL-1 impairs memory and alters affect. Interestingly, IL-1 can cause long-lasting changes in behavior, suggesting IL-1 can alter neuroplasticity. The neuroplastic effects of IL-1 are mediated via its cognate receptor, Interleukin-1 Type 1 Receptor (IL-1R1), and are dependent on the distribution and cell type(s) of IL-1R1 expression. Recent reports found that IL-1R1 expression is restricted to discrete subpopulations of neurons, astrocytes, and endothelial cells and suggest IL-1 can influence neural circuits directly through neuronal IL-1R1 or indirectly via non-neuronal IL-1R1. In this review, we analyzed multiple mechanisms by which IL-1/IL-1R1 signaling might impact neuroplasticity based upon the most up-to-date literature and provided potential explanations to clarify discrepant and confusing findings reported in the past.

Neuroinflammation and L-dopa-induced abnormal involuntary movements in 6-hydroxydopamine-lesioned rat model of Parkinson's disease are counteracted by combined administration of a 5-HT1A/1B receptor agonist and A2A receptor antagonist

Several lines of evidence have strongly implicated neuroinflammation in Parkinson's disease (PD) progression and l-dopa-induced dyskinesia. The present study investigated whether early subchronic pretreatment with the serotonin 5-HT_1A/1B receptor agonist eltoprazine plus the adenosine A_2A receptor antagonist preladenant counteracted l-dopa-induced abnormal involuntary movements (AIMs, index of dyskinesia), and neuroinflammation, in unilateral 6-hydroxydopamine(6-OHDA)-lesioned rat model of PD. The immunoreactivity of glial fibrillary acidic protein (GFAP), and the colocalization of ionized calcium binding adaptor molecule-1 (IBA-1), with interleukin (IL)-1β, tumor-necrosis-factor-α (TNF-α) and IL-10 were evaluated in the denervated caudate-putamen (CPu) and substantia nigra pars-compacta (SNc). The combined subchronic pretreatment with l-dopa plus eltoprazine and preladenant reduced AIMs induced by acute l-dopa challenge in these rats and decreased GFAP and IBA-1 immunoreactivity induced by the drug in both CPu and SNc, with reduction in IL-1β in IBA-1-positive cells in both CPu and SNc, and in TNF-α in IBA-1-positive cells in SNc. Moreover, a significant increase in IL-10 in IBA-1-positive cells was observed in SNc. Evaluation of immediate early-gene zif-268 (index of neuronal activation) after l-dopa challenge, showed an increase in its expression in denervated CPu of rats pretreated with l-dopa or l-dopa plus preladenant compared with vehicle, whereas rats pretreated with eltoprazine, with or without preladenant, had lower zif-268 expression. Finally, tyrosine hydroxylase and dopamine transporter examined to evaluate neurodegeneration, showed a significant equal decrease in all experimental groups. The present findings suggest that combination of l-dopa with eltoprazine and preladenant may be promising therapeutic strategy for delaying the onset of dyskinesia, preserving l-dopa efficacy and reducing neuroinflammation markers in nigrostriatal system of 6-OHDA-lesioned rats.

Epigenetic Regulation of Neuroinflammation in Parkinson's Disease

Neuroinflammation is one of the most significant factors involved in the initiation and progression of Parkinson's disease. PD is a neurodegenerative disorder with a motor disability linked with various complex and diversified risk factors. These factors trigger myriads of cellular and molecular processes, such as misfolding defective proteins, oxidative stress, mitochondrial dysfunction, and neurotoxic substances that induce selective neurodegeneration of dopamine neurons. This neuronal damage activates the neuronal immune system, including glial cells and inflammatory cytokines, to trigger neuroinflammation. The transition of acute to chronic neuroinflammation enhances the susceptibility of inflammation-induced dopaminergic neuron damage, forming a vicious cycle and prompting an individual to PD development. Epigenetic mechanisms recently have been at the forefront of the regulation of neuroinflammatory factors in PD, proposing a new dawn for breaking this vicious cycle. This review examined the core epigenetic mechanisms involved in the activation and phenotypic transformation of glial cells mediated neuroinflammation in PD. We found that epigenetic mechanisms do not work independently, despite being coordinated with each other to activate neuroinflammatory pathways. In this regard, we attempted to find the synergic correlation and contribution of these epigenetic modifications with various neuroinflammatory pathways to broaden the canvas of underlying pathological mechanisms involved in PD development. Moreover, this study highlighted the dual characteristics (neuroprotective/neurotoxic) of these epigenetic marks, which may counteract PD pathogenesis and make them potential candidates for devising future PD diagnosis and treatment.

Effects of task-oriented training combined with aerobic training on serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels in people with Parkinson's disease: A randomized controlled study

INTRODUCTION

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by the death of dopaminergic neurons in the substantia nigra pars compacta. Exercise training, which is incorporated both goal-based training such as task-oriented training (TOT) and aerobic training (AT), has been suggested to induce neuroprotection. However, molecular mechanisms which may underlie exercise-induced neuroprotection are still largely unknown. Thus, the aim of the present study was to investigate the effects of TOT combined with AT (TOT-AT) on serum brain-derived neurotrophic factor (BDNF), glial cell-derived growth factor (GDNF), insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) levels in people with PD (PwPD).

METHODS

Forty PwPD were randomized into 8-week of either exercise group (n = 20) or control group (n = 20). The exercise group received TOT-AT while the control group received only AT. Serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels determined with ELISA were assessed at baseline and after training.

RESULTS

A total of 29 PwPD completed this study. Our results showed no significant change in the serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels in both groups. After the intervention period, no significant difference was observed between the groups regarding the serum BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β levels.

CONCLUSION

TOT-AT could not be an effective exercise method for changing serum concentrations of BDNF, GDNF, IGF-1, VEGF, TNF-α, and IL-1β in the rehabilitation of PD.

Diagnostic and Prognostic Biomarkers for Myocardial Infarction

The incidence of myocardial infarction (MI) increases every year worldwide. Better diagnostic and prognostic biomarkers for clinical applications are the consistent pursuit of MI research. In addition to electrocardiogram, echocardiography, coronary angiography, etc., circulating biomarkers are essential for the diagnosis, prognosis, and treatment effect monitoring of MI patients. In this review, we assessed both strength and weakness of MI circulating biomarkers including: (1) originated from damaged myocardial tissues including current golden standard cardiac troponin, (2) released from non-myocardial tissues due to MI-induced systems reactions, and (3) preexisted in blood circulation before the occurrence of MI event. We also summarized newly reported MI biomarkers. We proposed that the biomarkers preexisting in blood circulation before MI incidents should be emphasized in research and development for MI prevention in near future.

Decoding the temporal nature of brain GR activity in the NFκB signal transition leading to depressive-like behavior

The fine-tuning of neuroinflammation is crucial for brain homeostasis as well as its immune response. The transcription factor, nuclear factor-κ-B (NFκB) is a key inflammatory player that is antagonized via anti-inflammatory actions exerted by the glucocorticoid receptor (GR). However, technical limitations have restricted our understanding of how GR is involved in the dynamics of NFκB in vivo. In this study, we used an improved lentiviral-based reporter to elucidate the time course of NFκB and GR activities during behavioral changes from sickness to depression induced by a systemic lipopolysaccharide challenge. The trajectory of NFκB activity established a behavioral basis for the NFκB signal transition involved in three phases, sickness-early-phase, normal-middle-phase, and depressive-like-late-phase. The temporal shift in brain GR activity was differentially involved in the transition of NFκB signals during the normal and depressive-like phases. The middle-phase GR effectively inhibited NFκB in a glucocorticoid-dependent manner, but the late-phase GR had no inhibitory action. Furthermore, we revealed the cryptic role of basal GR activity in the early NFκB signal transition, as evidenced by the fact that blocking GR activity with RU486 led to early depressive-like episodes through the emergence of the brain NFκB activity. These results highlight the inhibitory action of GR on NFκB by the basal and activated hypothalamic-pituitary-adrenal (HPA)-axis during body-to-brain inflammatory spread, providing clues about molecular mechanisms underlying systemic inflammation caused by such as COVID-19 infection, leading to depression.

Scopoletin Attenuates Intracerebral Hemorrhage-Induced Brain Injury and Improves Neurological Performance in Rats

BACKGROUND

Among the hypertension-related complications, the onset of intracerebral hemorrhage (ICH) is a destructive stage and is the most disabling type of stroke that has the highest death rate. At present, there is no promising treatment for ICH.

OBJECTIVES

The present investigation was aimed at evaluating the safeguarding effect of scopoletin against ICH-induced brain injury.

METHODS

We used Wistar male rats and divided them into 4 groups. Group 1 served as control, group 2 was induced with ICH, group 3 served as scopoletin-pretreated ICH rats, and group 4 as scopoletin drug control. During the experimental period, neurobehavioral outcome, cerebral edema, and neuroinflammation parameters were evaluated using RT-PCR and other biochemical analyses.

RESULTS

The rats that received scopoletin treatment demonstrated a significant attenuation in neurological deficits, neurodegeneration markers expression (TREM-1, SERPINE-1), and restored cerebral edema compared to ICH animals. On the other hand, an upsurge in inflammatory cytokines, for example, TNF-α, IL-13, IL-1β, and IL-17, was observed in ICH rats and was reduced to the level near normalcy in the scopoletin-treated groups.

CONCLUSION

Our investigations propose that the effectiveness of scopoletin in improving acute neurological function after ICH is promising, and this could be a lead molecule for the development of treatment plans in ICH treatment.

Contribution of the P2X4 Receptor in Rat Hippocampus to the Comorbidity of Chronic Pain and Depression

The hippocampus is an important region for the interaction between depression and pain. Studies show that the P2X4 receptor plays key role in neuropathic pain. This work investigated the potential implication of the P2X4 receptor in the hippocampus in comorbidity of chronic pain and depression. The rat model induced by chronic constriction injury (CCI) plus unpredictable chronic mild stress (UCMS) was used in this study. Our data showed that CCI plus UCMS treatment resulted in abnormal changes in pain and depressive-like behaviors in the rat, accompanied by the upregulated expression of P2X4, NLRP3 (NOD-like receptor protein 3) inflammasome, and interleukin-1β and the activation of p38 MAPK in the hippocampus. The P2X4 antagonist 5-BDBD reversed these abnormal changes in the hippocampus, relieved hippocampal neuronal damage, and alleviated the abnormal pain and depressive-like behaviors in the CCI plus UCMS treated rats. These findings suggest that the P2X4 receptor in the hippocampus may mediate and significantly contribute to the pathological processes of comorbid pain and depression.

Transcriptomic characterization of microglia activation in a rat model of ischemic stroke

Microglia are key regulators of inflammatory response after stroke and brain injury. To better understand activation of microglia as well as their phenotypic diversity after ischemic stroke, we profiled the transcriptome of microglia after 75 min transient focal cerebral ischemia in 3-month- and 12-month-old male spontaneously hypertensive rats. Microglia were isolated from the brains by FACS sorting on days 3 and 14 after cerebral ischemia. GeneChip Rat 1.0ST microarray was used to profile the whole transcriptome of sorted microglia. We identified an evolving and complex pattern of activation from 3 to 14 days after stroke onset. M2-like patterns were extensively and persistently upregulated over time. M1-like patterns were only mildly upregulated, mostly at day 14. Younger 3-month-old brains showed a larger microglial response in both pro- and anti-inflammatory pathways, compared to older 12-month-old brains. Importantly, our data revealed that after stroke, most microglia are activated towards a wide spectrum of novel polarization states beyond the standard M1/M2 dichotomy, especially in pathways related to TLR2 and dietary fatty acid signaling. Finally, classes of transcription factors that might potentially regulate microglial activation were identified. These findings should provide a comprehensive database for dissecting microglial mechanisms and pursuing neuroinflammation targets for acute ischemic stroke.

Bioactive components of ethnomedicine Eerdun Wurile regulate the transcription of pro-inflammatory cytokines in microglia

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Mongolian medicine Eerdun Wurile (EW) has remarkable neural recovery effect, and has been playing a key role in the clinical treatment of neurological disorders including ischemic stroke in Inner Mongolia Autonomous Region of China. The preliminary pharmacological studies in animal suggested that EW regulates the expression of trophic factors in brain lesion and may also balance the polarization of activated microglia (Gaowa et al., 2018).

AIM OF THE STUDY

The pool of leading bioactive chemicals underlying the therapeutic effects of EW has not been identified. Therefore, the mechanism of action of EW is poorly understood. This study was aimed to identify the major group of compounds that contribute to the inhibition of neuroinflammation during stroke recovery through regulation of microglia polarization.

MATERIALS AND METHODS

The extracts of EW in different solvents were evaluated for their inhibitory ability of cytokine (IP-10) expression in LPS stimulated BV2 cells. The most effective extract (of petroleum ether extract) was further separated to 18 fractionations on a semi-preparative HPLC column, which were assess for the IP-10 down-regulation efficiency by RT-qPCR. The potent isolate was further fractionated in 12 fractions, which showed fewer peaks. The fraction 6 from this isolates, which remarkably down-regulates cytokines expression including IP-10, TNFα and IL-1β, was analyzed on UPLC-qTOF MS. The key chemicals were measured for their cytokine inhibition in BV2 cells and mouse primary microglia.

RESULTS

After two consecutive fractionating by preparative HPLC, petroleum ether extraction of EW gave 12 fractions with relatively distinctive chromatograms. A particular fraction (fraction 6) preserved the inhibitory effects on expression of pro-inflammatory cytokines including IP-10, TNFα, IL-1β and iNOS. The result of UPLC-qTOF MS analysis showed that the fraction contains 21 chemicals including costunolide, alantolactone, myristicin and linolenic acid, which significantly down-regulate the expression of key pro-inflammatory cytokines in LPS stimulated BV2 cells as well as mouse primary microglia.

CONCLUSION

Collectively our data suggest that the bioactive chemical pool which is responsible for the therapeutic effects of EW can be extracted in petroleum ether, and fractionated to a relatively small multiple components. Such components include known anti-inflammatory chemicals, which may contribute to the possible microglia polarization in brain lesion during the recovery of ischemic stroke.

Aspirin in stroke patients modifies the immunomodulatory interactions of marrow stromal cells and monocytes

BACKGROUND AND OBJECTIVE

Most stroke patients are prescribed aspirin (ASA) to adjust blood coagulability. Marrow stromal cells (MSCs) are being tested in clinical trials for stroke patients who likely are prescribed aspirin. One of the principal mechanisms of action of MSCs and ASA is modulation of the inflammatory response, including those mediated by monocytes (Mo). Thus, here we tested if aspirin can modify anti-inflammatory properties of MSCs or Mo alone, and in combination.

METHODS

Mo were isolated at 24 h of stroke onset from ischemic stroke patients with NIHSS ranging from 11 to 20 or from healthy controls. Human bone marrow-derived MSCs from healthy subjects were used at passage 3. Mo, MSCs, and MSCs-Mo co-cultures were exposed to ASA at clinically relevant doses. The secretome profile of inflammatory mediators was measured using Magpix multiplex cytokine array. Viability was measured using MTT assay. Linear mixed effect model was used for statistical analysis.

RESULTS

Overall Mo from control subjects exposed to ASA showed increased secretion of IL-1RA, IL-8, MCP-1, and TNF-α and Mo from stroke patients showed greater release of IL-1RA and MCP-1. In MSCs-Mo co-cultures, ASA added to co-cultures of control Mo reduced fractalkine secretion while it increased the fractalkine secretion when added to Mo from stroke patients. In addition, in co-cultures independent of Mo origin, ASA reduced IL-6, IL-8, MCP-1, and TNF-α.

CONCLUSIONS

Aspirin in acute stroke patients may modulate the secretome profile of Mo and MSCs, thus potentially modulating immune and inflammatory responses associated with stroke. Our results suggest that stroke trials involving the use of intravenous MSCs should consider the effect of aspirin as a confounding factor.

Acupuncture treatment is associated with a decreased risk of developing stroke in patients with depression: A propensity-score matched cohort study

BACKGROUND

Depression had a significantly increased risk of stroke. Some patients with depression seek acupuncture treatment. The aim of this study is to investigate the association between acupuncture treatment and risk of developing stroke in patients with depression.

METHODS

Patients with newly diagnosed depression above 18 years old between 1997 and 2010 were selected from the Taiwanese National Health Insurance Research Database, and followed up until the end of 2013. The 1:1 propensity score method was used to match an equal number of patients (N = 13,823) in the acupuncture and non-acupuncture cohorts, based on characteristics including sex, age, baseline comorbidity and drug used. The outcome measurement was the comparison of stroke incidence in the two cohorts. We used the Cox regression model and the Kaplan-Meier method to estimate the risk of developing stroke.

RESULTS

Compared with the non-acupuncture cohort, patients who received acupuncture treatment had a lower risk of stroke (adjusted hazard ratio (HR) = 0.49, 95% confidential interval = 0.45-0.52) after adjustment for age, sex, comorbidities and drugs used. Regarding the two types of stroke, acupuncture users also had lower risk of hemorrhagic or ischemic stroke (adjusted HR = 0.37 and 0.49, respectively). The cumulative incidence of stroke in the acupuncture cohort was significantly lower than that of the non-acupuncture cohort (log-rank test, p < 0.001). At the 5th year of follow-up, 7.22% of acupuncture users had stroke onset compared with 14% in the non-acupuncture cohort.

LIMITATIONS

The database provided information of antidepressants but not the severity of depression. Details of the life style and selection of acupoints were also not provided.

CONCLUSIONS

The present study revealed that acupuncture reduced the risk of developing stroke in depression patients in Taiwan. Further clinical studies investigating the mechanisms and efficacy of acupuncture are warranted.

Distinct cytokine profiles in human brains resilient to Alzheimer's pathology

Our group has previously studied the brains of some unique individuals who are able to tolerate robust amounts of Alzheimer's pathological lesions (amyloid plaques and neurofibrillary tangles) without experiencing dementia while alive. These rare resilient cases do not demonstrate the patterns of neuronal/synaptic loss that are normally found in the brains of typical demented Alzheimer's patients. Moreover, they exhibit decreased astrocyte and microglial activation markers GFAP and CD68, suggesting that a suppressed neuroinflammatory response may be implicated in human brain resilience to Alzheimer's pathology. In the present work, we used a multiplexed immunoassay to profile a panel of 27 cytokines in the brains of controls, typical demented Alzheimer's cases, and two groups of resilient cases, which possessed pathology consistent with either high probability (HP, Braak stage V-VI and CERAD 2-3) or intermediate probability (IP, Braak state III-IV and CERAD 1-3) of Alzheimer's disease in the absence of dementia. We used a multivariate partial least squares regression approach to study differences in cytokine expression between resilient cases and both Alzheimer's and control cases. Our analysis identified distinct profiles of cytokines in the entorhinal cortex (one of the earliest and most severely affected brain regions in Alzheimer's disease) that are up-regulated in both HP and IP resilient cases relative to Alzheimer's and control cases. These cytokines, including IL-1β, IL-6, IL-13, and IL-4 in HP resilient cases and IL-6, IL-10, and IP-10 in IP resilient cases, delineate differential inflammatory activity in brains resilient to Alzheimer's pathology compared to Alzheimer's cases. Of note, these cytokines all have been associated with pathogen clearance and/or the resolution of inflammation. Moreover, our analysis in the superior temporal sulcus (a multimodal association cortex that consistently accumulates Alzheimer's pathology at later stages of the disease along with overt symptoms of dementia) revealed increased expression of neurotrophic factors, such as PDGF-bb and basic FGF in resilient compared to AD cases. The same region also had reduced expression of chemokines associated with microglial recruitment, including MCP-1 in HP resilient cases and MIP-1α in IP resilient cases compared to AD. Altogether, our data suggest that different patterns of cytokine expression exist in the brains of resilient and Alzheimer's cases, link these differences to reduced glial activation, increased neuronal survival and preserved cognition in resilient cases, and reveal specific cytokine targets that may prove relevant to the identification of novel mechanisms of brain resiliency to Alzheimer's pathology.

Interleukin 1 receptor antagonist (IL1RA) gene polymorphism and levels associated with adverse outcome in severe community-acquired pneumonia in children: A hospital-based study in India

BACKGROUND

High morbidity and mortality due to community-acquired pneumonia (CAP) is seen in children under 5 years of age in India. Besides identified risk factors for CAP, there may be a phenotype-genotype association with cytokines, resulting in enhanced inflammatory response resulting in the adverse outcome (AO), namely complications and death.

AIM

To assess the association of IL1RA gene polymorphism on serum levels of IL1RA and with AO in children under 5 years of age hospitalized with WHO-defined severe CAP.

METHOD

A prospective cohort study with nested case-control design conducted in a tertiary care teaching hospital after obtaining institutional ethical approval. Included were children between 2 and 59 months of age hospitalized with WHO-defined severe CAP with consistent radiological abnormalities. Excluded were those with suspected or proven cystic fibrosis, pulmonary tuberculosis, malignancy, immunodeficiency, and congenital heart disease. Polymerase chain reaction (PCR) was used to analyze the Variable Number of Tandem Repeats (VNTRs) of IL1RA gene polymorphism and ELISA test to detect serum levels of IL1RA.

RESULTS

From 2014 to 2016, of 420 screened cases, 350 were eligible and included, of which 132 (37.7%) had no complication and 218 (62.3%) had AO, which included complications like empyema, pyopneumothorax, acute respiratory distress syndrome (ARDS), and septic shock of these 24 (6.9%) expired. Higher risk of AO was seen in A2A2 genotype (OR 11.18, p 0.0001) and lower in A1A1 genotype (OR 0.18, P < 0.0001). Serum IL1RA (ng/mL) was statistically significantly elevated in CAP with AO (2.55 ± 1.44) versus uncomplicated (0.87 ± 0.52) (P < 0.0001).

CONCLUSION

In IL1RA gene, A1A1 genotype was associated with lower risk and A2A2 genotype with increased the risk of AO. Higher serum levels of IL1RA were found in A2A2 genotype indicating possibly enhanced inflammatory response resulting in AO of CAP.

A potential gliovascular mechanism for microglial activation: differential phenotypic switching of microglia by endothelium versus astrocytes

BACKGROUND

Activation of microglia can result in phenotypic and functional diversity. However, the pathways that trigger different states of microglial activation remain to be fully understood. Here, we hypothesized that after injury, astrocytes and endothelium may contribute to a gliovascular switch for microglial activation.

METHODS

Astrocytes or cerebral endothelial cells were subjected to oxygen glucose deprivation, then conditioned media were transferred to microglia. The release of TNFα, IL-1β, IL-10, and IGF-1 was measured using ELISA. Surface markers of CD11b, CD45, CD86, and MHC class II were detected by flow cytometry. mRNA expression of iNOS, CD86, CD206, Arginase1, and transcription factors was measured using real-time PCR. Microglial function including migration and phagocytosis was assessed. Dendritogenesis was determined by counting the number of primary dendrites, secondary dendrites, and dendritic ends in the neurons exposed to either endothelial- or astrocyte-activated microglia.

RESULTS

Exposure to conditioned media from oxygen-glucose-deprived cerebral endothelial cells or oxygen-glucose-deprived astrocytes activated microglia into different forms. The endothelium converted ramified microglia into amoeboid shapes; increased the release of TNFα, IL-1β, and IL-10; decreased IGF-1; upregulated iNOS expression; and inhibited microglial migration and phagocytosis. In contrast, astrocytes increased microglial production of IGF-1, upregulated CD206 expression, and enhanced microglial phagocytosis. These opposing effects of the endothelium versus astrocyte crosstalk partly mirror potentially deleterious versus potentially beneficial microglial phenotypes. Consistent with this idea, endothelial-activated microglia were neurotoxic, whereas astrocyte-activated microglia did not affect neuronal viability but instead promoted neuronal dendritogenesis.

CONCLUSION

These findings provide proof of concept that endothelial cells and astrocytes provide differing signals to microglia that influence their activation states and suggest that a gliovascular switch may be involved in the balance between beneficial versus deleterious microglial properties.

Deciphering variability in the role of interleukin-1β in Parkinson's disease

Although the role of inflammation in neurodegeneration has been well acknowledged, less is known on the issue of each cytokine in specific neurodegenerative diseases. In this review, we will present evidence elucidating that interleukin-1β (IL-1β) has a multi-faceted character in pathogenesis of Parkinson's disease, which is a progressive neurodegenerative disorder. Increased levels of IL-1β were found in PD patients. Besides, PD symptoms were observed in IL-1β wild-type, but not deficient, animals. These lines of evidence suggest that IL-1β may contribute to the initiation or progression of PD. On the other hand, some studies reported decreased levels of IL-1β in PD patients. Also, genetic studies provided evidence suggesting that IL-1β may protect individuals against PD. Presumably, the broad range of IL-1β role is due to its interaction with both upstream and downstream mediators. Differences in IL-1β levels could be because of glia population (i.e. microglia and astrocytes), mitogen-activated protein kinase and nuclear factor κ light-chain-enhancer of activated B cells signaling pathways, and several mediators (including cyclooxygenase, neurotrophic factors, reactive oxygen species, caspases, heme oxygenase-1, and matrix metalloproteinases). Although far from practice at this point, unraveling theoretical therapeutic targets based on the up-down IL-1β neuroweb could facilitate the development of strategies that are likely to be used for pharmaceutical designs of anti-neurodegenerative drugs of the future.

Protection of Mcc950 against high-glucose-induced human retinal endothelial cell dysfunction

Diabetic retinopathy (DR) is a well-known microvascular complication related to inflammation. Mcc950 is a potent and specific inhibitor of the NLRP3 inflammasome but its influence on DR has not been studied. Thus, we evaluated the anti-inflammatory effects of Mcc950 on high-glucose-induced human retinal endothelial cells (HRECs) and the potential underlying mechanism. In surgical excised proliferative membranes from DR patients, high expression of NLRP3, caspase 1 and IL-1β was observed and co-localization of NLRP3 and IL-1β occurred in CD31+ labeled HRECs. Moreover, in high-glucose-stimulated HRECs, increased production of the NLRP3 inflammasome activation and severe apoptosis were rescued with Mcc950 treatment. Additionally, the inhibitory effect of Mcc950 was mimicked through downregulation of NEK7 by siRNA in high-glucose-induced HRECs and Mcc950 treatment remarkably inhibited Nek7 and NLRP3 interactions by co-immunoprecipitation, suggesting that Mcc950 may be a potentially protective agent against inflammation, likely via downregulation of the Nek7-NLRP3 pathway. In conclusion, Mcc950 inhibited HREC dysfunction under high-glucose conditions and this research may offer insight for future pharmaceutical approaches for treating DR.

Sesamol attenuates oxidative stress, apoptosis and inflammation in focal cerebral ischemia/reperfusion injury

The aim of the present study was to evaluate the therapeutic potential of sesamol treatment on focal ischemia/reperfusion (I/R) injury in the rat brain. The results demonstrated that pretreatment with sesamol seven days prior to focal cerebral I/R injury had significant positive effects, including improvements in neurological deficits (P<0.05), and a reduction in malondialdehyde content and elevation of antioxidant levels (superoxide dismutase, glutathione and glutatione peroxidase; both P<0.05). Furthermore, levels of B cell lymphoma-2 (Bcl-2)-associated X protein and caspase-3 were significantly downregulated, whereas the level of Bcl-2 was effectively increased. Conversely, the mRNA expression of proinflammatory cytokines were significantly reduced in focal cerebral I/R injury rats upon sesamol intervention. Therefore, the beneficial effects of sesamol on cerebral I/R injury may be due to the reduction of oxidative stress, inhibition of apoptosis and inflammation. The findings of the present study suggest that sesamol supplementation may serve as potent adjuvant in the treatment of focal cerebral ischemia/reperfusion injury due to its neuroprotective effects.

Polysaccharides from Ganoderma lucidum attenuate microglia-mediated neuroinflammation and modulate microglial phagocytosis and behavioural response

Background

Ganoderma lucidum (GL) has been widely used in Asian countries for hundreds of years to promote health and longevity. The pharmacological functions of which had been classified, including the activation of innate immune responses, suppression of tumour and modulation of cell proliferations. Effective fractions of Ganoderma lucidum polysaccharides (GLP) had already been reported to regulate the immune system. Nevertheless, the role of GLP in the microglia-mediated neuroinflammation has not been sufficiently elucidated. Further, GLP effect on microglial behavioural modulations in correlation with the inflammatory responses remains to be unravelled. The aim of this work was to quantitatively analyse the contributions of GLP on microglia.

Methods

The BV2 microglia and primary mouse microglia were stimulated by lipopolysaccharides (LPS) and amyloid beta₄₂ (Aβ₄₂) oligomer, respectively. Investigation on the effect of GLP was carried by quantitative determination of the microglial pro- and anti-inflammatory cytokine expressions and behavioural modulations including migration, morphology and phagocytosis. Analysis of microglial morphology and phagocytosis modulations was confirmed in the zebrafish brain.

Results

Quantitative results revealed that GLP down-regulates LPS- or Aβ-induced pro-inflammatory cytokines and promotes anti-inflammatory cytokine expressions in BV-2 and primary microglia. In addition, GLP attenuates inflammation-related microglial migration, morphological alterations and phagocytosis probabilities. We also showed that modulations of microglial behavioural responses were associated with MCP-1 and C1q expressions.

Conclusions

Overall, our study provides an insight into the GLP regulation of LPS- and Aβ-induced neuroinflammation and serves an implication that the neuroprotective function of GLP might be achieved through modulation of microglial inflammatory and behavioural responses.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0839-0) contains supplementary material, which is available to authorized users.

MORIN MITIGATES OXIDATIVE STRESS, APOPTOSIS AND INFLAMMATION IN CEREBRAL ISCHEMIC RATS

Background:

Morin is a flavanoid which exhibits potent antioxidant activity in various oxidative stress related diseases. The current study was attempted to scrutinize the preclinical bio-efficacy of morin on focal ischemia.

Methods:

The animal model of focal cerebral ischemic injury was done by midbrain carotid artery occlusion (MCAO) method, followed by Morin (30mg/kg) administration for seven days.

Results:

The outcome of the study showed that treatment with morin displayed positive effects in reducing the focal cerebral ischemia. This effect was evident with the improvements in neurological deficits, reduction in MDA content and elevation of antioxidant levels (SOD, GSH and Gpx). Furthermore, protein expression of Bax and caspase-3 were effectively down-regulated, whilst the expression of Bcl-2 was significantly elevated. On the other hand, the mRNA expression of proinflammatory cytokines was significantly reduced in focal cerebral ischemic rats upon morin intervention.

Conclusion:

Thus, the beneficial effects of morin on cerebral ischemia assault may result from the reduction of oxidative stress, inhibition of apoptosis and inflammation. The neuroprotective effects of morin supplement may serve as potent adjuvant in the amelioration of ischemic stroke.

Selective induction of IL-1β after a brief isoflurane anesthetic in children undergoing MRI examination

PURPOSE

To determine if isoflurane anesthesia without surgery causes systemic inflammation in children. Inflammation is targeted as responsible for the development of many neurologic pathologies. The effect will be evaluated by measuring serum cytokine levels before and after isoflurane anesthesia. The possible neurotoxic effect of anesthetic agents is a concern in pediatric anesthesia. Questions remain as to the true effects of anesthesia alone on systemic inflammation. The current study assesses systemic inflammatory response to general anesthesia in children not exposed to surgical stress.

METHODS

Twenty-five patients, aged 6 months to 11 years undergoing MRI scanning were recruited. Patients with ASA Physical Status Classification >II, known neurologic disease, prematurity, recent infection, or current treatment with anti-inflammatory medications were excluded. Each patient received a sevoflurane induction, peripheral intravenous catheterization, and laryngeal mask airway placement. Isoflurane was titrated to ensure adequate depth of anesthesia. Two peripheral blood samples were obtained: one immediately after placement of the PIV and one upon arrival to the post-anesthesia care unit. Serum cytokine levels were compared between pre- and post-isoflurane time points using paired t tests.

RESULTS

For all patients, interleukin-1β increased after isoflurane when compared to pre-isoflurane samples (pre = 25.97 ± 9.01, post = 38.53 ± 16.56, p = 0.0002). Serum levels of IL-6 (pre = 2.28 ± 2.27, post = 2.04 ± 2.15, p = 0.146) and tumor necrosis factor-α (pre = 94.26 ± 18.07, post = 85.84 ± 12.12, p = 0.057) were not significantly changed. Interleukin-10 and vascular endothelial growth factor were undetectable in pre- and post-isoflurane samples at a minimum detection threshold of 6.6 and 10 pg/ml, respectively.

CONCLUSIONS

A brief (approximately 60 min) exposure to isoflurane general anesthesia, without induced surgical stress, significantly increased serum IL-1β, a selective activation marker of systemic inflammation (IL-1β pathway).

Differential Neuroprotective Effects of Interleukin-1 Receptor Antagonist on Spinal Cord Neurons after Excitotoxic Injury

Secondary damage following spinal cord injury (SCI) induces neuronal damage through inflammatory and excitotoxic pathways. We hypothesized that the interleukin-1 receptor antagonist (IL1RA) protects neuronal populations and suppresses apoptosis and gliosis after injury. Spinal cord slice cultures (SCSCs) were subjected to excitotoxic injury with N-methyl-D-aspartate (NMDA) and treated with IL1RA. Immunohistochemistry for neuronal nuclei (NeuN), MacII, glial fibrillary acidic protein, and TdT-mediated dUTP nick end labelling stains were used to evaluate neuronal survival, glial activation, and apoptosis. Treatment with IL1RA significantly reduced the number of apoptotic cells in both NMDA-lesioned and unlesioned cultures. Experimental injury with NMDA reduced the number of NeuN-positive ventral horn neurons, and IL1RA treatment counteracted this loss 1 day after injury. However, IL1RA had no effect on the number of presumable Renshaw cells, identified by their selective expression of the cholinergic nicotinic α2-receptor subunit (Chrna2). Activated microglial cells were more numerous in NMDA-lesioned cultures 1 day after injury, and IL1RA significantly reduced their numbers. We conclude that IL1RA modulates neuronal apoptosis and microglial activation in excitotoxically injured SCSCs. Renshaw cells were more susceptible to excitotoxic injury than other neurons and were not rescued by IL1RA treatment. Modulation of IL-1-mediated pathways may thus be effective in reducing excitotoxically induced neuronal damage after SCI, however only in specific neuronal populations, such as ventral horn neurons. These findings motivate further investigations of the possibility to antagonize inflammatory pathways after SCI.

Knockout of Ccr2 alleviates photoreceptor cell death in rodent retina exposed to chronic blue light

Age-related macular degeneration (AMD), the leading cause of visual loss after the age of 60 years, is a degenerative retinal disease involving a variety of environmental and hereditary factors. Although it has been implicated that immune system is involved in the disease progression, the exact role that microglia has is still unclear. Here we demonstrated that knockout of Ccr2 gene could alleviate photoreceptor cell death in mice retinas exposed to chronic blue light. In Ccr2^−/− mice, a damaged microglia recruitment was shown in retina and this could protect the visual function in electroretinogram and alleviate the photoreceptor apoptosis, which thus helped attenuate the blue light-induced retinopathy. We further found an increased co-location of NLRP3, Iba-1, and IL-1β in fluorescence and a concomitant increased protein expression of NLRP3, caspase-1, and IL-1β in western blotting in chronic blue light-induced retinopathy. Moreover, the activation of microglia and their cellular NLRP3 inflammasomes occurred as an earlier step before the structural and functional damage of the mice retinas, which collectively supported that microglial NLRP3 inflammasome might be the key to the chronic blue light-induced retinopathy.

Fumarate modulates the immune/inflammatory response and rescues nerve cells and neurological function after stroke in rats

BACKGROUND

Dimethyl fumarate (DMF), working via its metabolite monomethylfumarate (MMF), acts as a potent antioxidant and immunomodulator in animal models of neurologic disease and in patients with multiple sclerosis. These properties and their translational potential led us to investigate whether DMF/MMF could also protect at-risk and/or dying neurons in models of ischemic stroke in vitro and in vivo. Although the antioxidant effects have been partially addressed, the benefits of DMF immunomodulation after ischemic stroke still need to be explored.

METHODS

In vitro neuronal culture with oxygen-glucose deprivation and rats with middle cerebral artery occlusion were subjected to DMF/MMF treatment. Live/dead cell counting and LDH assay, as well as behavioral deficits, plasma cytokine assay, western blots, real-time PCR (Q-PCR) and immunofluorescence staining, were used to evaluate the mechanisms and neurological outcomes.

RESULTS

We found that MMF significantly rescued cortical neurons from oxygen-glucose deprivation (OGD) in culture and suppressed pro-inflammatory cytokines produced by primary mixed neuron/glia cultures subjected to OGD. In rats, DMF treatment significantly decreased infarction volume by nearly 40 % and significantly improved neurobehavioral deficits after middle cerebral artery occlusion (MCAO). In the acute early phase (72 h after MCAO), DMF induced the expression of transcription factor Nrf2 and its downstream mediator HO-1, important for the protection of infarcted cells against oxidative stress. In addition to its antioxidant role, DMF also acted as a potent immunomodulator, reducing the infiltration of neutrophils and T cells and the number of activated microglia/macrophages in the infarct region by more than 50 % by 7-14 days after MCAO. Concomitantly, the levels of potentially harmful pro-inflammatory cytokines were greatly reduced in the plasma and brain and in OGD neuron/glia cultures.

CONCLUSIONS

We conclude that DMF is neuroprotective in experimental stroke because of its potent immunomodulatory and antioxidant effects and thus may be useful as a novel therapeutic agent to treat stroke in patients.

Mesenchymal stem cell-based treatments for stroke, neural trauma, and heat stroke

BACKGROUND

Mesenchymal stem cell (MSC) transplantation has been reported to improve neurological function following neural injury. Many physiological and molecular mechanisms involving MSC therapy-related neuroprotection have been identified.

METHODS

A review is presented of articles that pertain to MSC therapy and diverse brain injuries including stroke, neural trauma, and heat stroke, which were identified using an electronic search (e.g., PubMed), emphasize mechanisms of MSC therapy-related neuroprotection. We aim to discuss neuroprotective mechanisms that underlie the beneficial effects of MSCs in treating stroke, neural trauma, and heatstroke.

RESULTS

MSC therapy is promising as a means of augmenting brain repair. Cell incorporation into the injured tissue is not a prerequisite for the beneficial effects exerted by MSCs. Paracrine signaling is believed to be the most important mediator of MSC therapy in brain injury. The multiple mechanisms of action of MSCs include enhanced angiogenesis and neurogenesis, immunomodulation, and anti-inflammatory effects. Microglia are the first source of the inflammatory cascade during brain injury. Cytokines, including tumor necrosis factor-α, interleukin-1β, and interleukin-6, are significantly produced by microglia in the brain after experimental brain injury. The proinflammatory M1 phenotype of microglia is associated with tissue destruction, whereas the anti-inflammatory M2 phenotype of microglia facilitates repair and regeneration. MSC therapy may improve outcomes of ischemic stroke, neural trauma, and heatstroke by inhibiting the activity of M1 phenotype of microglia but augmenting the activity of M2 phenotype of microglia.

CONCLUSION

This review offers a testable platform for targeting microglial-mediated cytokines in clinical trials based upon the rational design of MSC therapy in the future. MSCs that are derived from the placenta provide a great choice for stem cell therapy. Although targeting the microglial activation is an important approach to reduce the burden of the injury, it is not the only one. This review focuses on this specific aspect.

Clinical Trials of Immunomodulation in Ischemic Stroke

Inflammatory mechanisms are currently considered as a prime target for stroke therapy. There is evidence from animal studies that immune signals and mediators can have both detrimental and beneficial effects in particular stages of the disease process. Moreover, several of these mechanisms are turned on with sufficient delay after ischemia onset to make them amenable to therapeutic intervention. Several clinical proof-of concept trials have investigated the efficacy of different immunomodulatory approaches in patients with stroke. Trials targeting the innate immune system have focused on reduction of microglial activation, inhibition of neutrophil migration, and interleukin-1 receptor blockade, suggesting that interleukin-1 receptor blockade may be a promising strategy. Studies aiming at halting T-cell migration have also been undertaken with controversial findings regarding prevention of infarct growth in neuroimaging studies. Consistently, recent proof-of-concept trials targeting lymphocytes with drugs such as natalizumab and fingolimod have yielded some promising results on clinical endpoints, but confirmation in larger trials is needed. At present, the understanding of the role of immune mechanisms in neurorepair and neurodegeneration is limited. Improving long-term brain function by mitigating prolonged neuroinflammation that was triggered by acute brain injury could be a strategy in addition to neuroprotection.

Probucol inhibits LPS-induced microglia activation and ameliorates brain ischemic injury in normal and hyperlipidemic mice

AIM

Increasing evidence suggests that probucol, a lipid-lowering agent with anti-oxidant activities, may be useful for the treatment of ischemic stroke with hyperlipidemia via reduction in cholesterol and neuroinflammation. In this study we examined whether probucol could protect against brain ischemic injury via anti-neuroinflammatory action in normal and hyperlipidemic mice.

METHODS

Primary mouse microglia and murine BV2 microglia were exposed to lipopolysaccharide (LPS) for 3 h, and the release NO, PGE2, IL-1β and IL-6, as well as the changes in NF-κB, MAPK and AP-1 signaling pathways were assessed. ApoE KO mice were fed a high-fat diet containing 0.004%, 0.02%, 0.1% (wt/wt) probucol for 10 weeks, whereas normal C57BL/6J mice received probucol (3, 10, 30 mg·kg(-1)·d(-1), po) for 4 d. Then all the mice were subjected to focal cerebral ischemia through middle cerebral artery occlusion (MCAO). The neurological deficits were scored 24 h after the surgery, and then brains were removed for measuring the cerebral infarct size and the production of pro-inflammatory mediators.

RESULTS

In LPS-treated BV2 cells and primary microglial cells, pretreatment with probucol (1, 5, 10 μmol/L) dose-dependently inhibited the release of NO, PGE2, IL-1β and IL-6, which occurred at the transcription levels. Furthermore, the inhibitory actions of probucol were associated with the downregulation of the NF-κB, MAPK and AP-1 signaling pathways. In the normal mice with MCAO, pre-administration of probucol dose-dependently decreased the infarct volume and improved neurological function. These effects were accompanied by the decreased production of pro-inflammatory mediators (iNOS, COX-2, IL-1, IL-6). In ApoE KO mice fed a high-fat diet, pre-administration of 0.1% probucol significantly reduced the infarct volume, improved the neurological deficits following MCAO, and decreased the total- and LDL-cholesterol levels.

CONCLUSION

Probucol inhibits LPS-induced microglia activation and ameliorates cerebral ischemic injury in normal and hyperlipidemic mice via its anti-neuroinflammatory actions, suggesting that probucol has potential for the treatment of patients with or at risk for ischemic stroke and hyperlipidemia.

Annexin A1 translocates to nucleus and promotes the expression of pro-inflammatory cytokines in a PKC-dependent manner after OGD/R

Annexin A1 (ANXA1) is a protein known to have multiple roles in the regulation of inflammatory responses. In this study, we find that after oxygen glucose deprivation/reoxygenation (ODG/R) injury, activated PKC phosphorylated ANXA1 at the serine 27 residue (p27S-ANXA1), and promoted the translocation of p27S-ANXA1 to the nucleus of BV-2 microglial cells. This in turn induced BV-2 microglial cells to produce large amounts of pro-inflammatory cytokines. The phenomenon could be mimicked by either transfecting a mutant form of ANXA1 with its serine 27 residue converted to aspartic acid, S27D, or by using the PKC agonist, phorbol 12-myristate 13-acetate (PMA) in these microglial cells. In contrast, transfecting cells with an ANXA1 S27A mutant (serine 27 converted to alanine) or treating the cells with the PKC antagonist, GF103209X (GF) reversed this effet. Our study demonstrates that ANXA1 can be phosphorylated by PKC and is subsequently translocated to the nucleus of BV-2 microglial cells after OGD/R, resulting in the induction of pro-inflammatory cytokines.

The Anti-Inflammatory Activity of Eucommia ulmoides Oliv. Bark. Involves NF-κB Suppression and Nrf2-Dependent HO-1 Induction in BV-2 Microglial Cells

In the present study, we investigated the anti-inflammatory properties of Eucommia ulmoides Oliv. Bark. (EUE) in lipopolysaccharide (LPS)-stimulated microglial BV-2 cells and found that EUE inhibited LPS-mediated up-regulation of pro-inflammatory response factors. In addition, EUE inhibited the elevated production of pro-inflammatory cytokines, mediators, and reactive oxygen species (ROS) in LPS-stimulated BV-2 microglial cells. Subsequent mechanistic studies revealed that EUE suppressed LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs), phosphoinositide-3-kinase (PI3K)/Akt, glycogen synthase kinase-3β (GSK-3β), and their downstream transcription factor, nuclear factor-kappa B (NF-κB). EUE also blocked the nuclear translocation of NF-κB and inhibited its binding to DNA. We next demonstrated that EUE induced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression. We determined that the significant up-regulation of HO-1 expression by EUE was a consequence of Nrf2 nuclear translocation; furthermore, EUE increased the DNA binding of Nrf2. In contrast, zinc protoporphyrin (ZnPP), a specific HO-1 inhibitor, blocked the ability of EUE to inhibit NO and PGE₂ production, indicating the vital role of HO-1. Overall, our results indicate that EUE inhibits pro-inflammatory responses by modulating MAPKs, PI3K/Akt, and GSK-3β, consequently suppressing NF-κB activation and inducing Nrf2-dependent HO-1 activation.

Inflammogenesis of Secondary Spinal Cord Injury

Spinal cord injury (SCI) and spinal infarction lead to neurological complications and eventually to paraplegia or quadriplegia. These extremely debilitating conditions are major contributors to morbidity. Our understanding of SCI has certainly increased during the last decade, but remains far from clear. SCI consists of two defined phases: the initial impact causes primary injury, which is followed by a prolonged secondary injury consisting of evolving sub-phases that may last for years. The underlying pathophysiological mechanisms driving this condition are complex. Derangement of the vasculature is a notable feature of the pathology of SCI. In particular, an important component of SCI is the ischemia-reperfusion injury (IRI) that leads to endothelial dysfunction and changes in vascular permeability. Indeed, together with endothelial cell damage and failure in homeostasis, ischemia reperfusion injury triggers full-blown inflammatory cascades arising from activation of residential innate immune cells (microglia and astrocytes) and infiltrating leukocytes (neutrophils and macrophages). These inflammatory cells release neurotoxins (proinflammatory cytokines and chemokines, free radicals, excitotoxic amino acids, nitric oxide (NO)), all of which partake in axonal and neuronal deficit. Therefore, our review considers the recent advances in SCI mechanisms, whereby it becomes clear that SCI is a heterogeneous condition. Hence, this leads towards evidence of a restorative approach based on monotherapy with multiple targets or combinatorial treatment. Moreover, from evaluation of the existing literature, it appears that there is an urgent requirement for multi-centered, randomized trials for a large patient population. These clinical studies would offer an opportunity in stratifying SCI patients at high risk and selecting appropriate, optimal therapeutic regimens for personalized medicine.

Rg3-enriched ginseng extract ameliorates scopolamine-induced learning deficits in mice

Background

Ginseng (Panax ginseng C.A. Meyer) has been used as a traditional herb in the treatment of many medical disorders. Ginsenosides, which are triterpene derivatives that contain sugar moieties, are the main pharmacological ingredients in ginseng. This study was designed to investigate the effect of ginsenoside Rg3-enriched ginseng extract (Rg3GE) on scopolamine-induced memory impairment in mice.

Methods

Rg3GE (50 and 100 mg/kg) were administered to C57BL/6 mice by oral gavage for 14 days (days 1–14). Memory impairment was induced by scopolamine (1 mg/kg, intraperitoneal injection) for 6 days (days 914). The Morris water maze test was used to assess hippocampus-dependent spatial memory. The effects of scopolamine with or without Rg3GE on acetylcholinesterase and nuclear factor-κB (NF-κB) in the hippocampus were also examined.

Results

Mice with scopolamine treatment alone showed impairments in the acquisition and retention of spatial memory. Mice that received Rg3GE and scopolamine showed no scopolamine-induced impairment in the acquisition of spatial memory. Oral administration of Rg3GE suppressed the scopolamine-mediated increase in acetylcholinesterase activity and stimulation of the NF-κB pathway (i.e., phosphorylation of p65) in the hippocampus.

Conclusion

These findings suggest that Rg3GE may stabilize scopolamine-induced memory deficits through the inhibition of acetylcholinesterase activity and NF-κB signaling in the hippocampus.

Ischemic, traumatic and neurodegenerative brain inflammatory changes

This review serves to link the role of the immune system in the neuropathology of acute ischemic stroke, traumatic brain injury and neurodegenerative disease. The blood–brain barrier delineates the CNS from the peripheral immune system. However, the blood–cerebrospinal fluid barrier acts as a gate between the periphery and the brain, permitting immune activity crosstalk and modulation. In acute ischemic stroke, traumatic brain injury and other neurodegenerative diseases, the blood–brain barrier is compromised and an influx of inflammatory cells and plasma proteins occurs, resulting in edema, demyelination, cell dysfunction and death, and neurobehavioral changes. The role of the complement system, key cytokines, microglia and other neuroglia in brain degenerative pathology will be discussed.

Treadmill exercise promotes neuroprotection against cerebral ischemia-reperfusion injury via downregulation of pro-inflammatory mediators

BACKGROUND

Stroke is one of the major causes of morbidity and mortality worldwide, which is associated with serious physical deficits that affect daily living and quality of life and produces immense public health and economic burdens. Both clinical and experimental data suggest that early physical training after ischemic brain injury may reduce the extent of motor dysfunction. However, the exact mechanisms have not been fully elucidated. The aim of this study was to investigate the effects of aerobic exercise on neuroprotection and understand the underlying mechanisms.

MATERIALS AND METHODS

Middle cerebral artery occlusion (MCAO) was conducted to establish a rat model of cerebral ischemia-reperfusion injury to mimic ischemic stroke. Experimental animals were divided into the following three groups: sham (n=34), MCAO (n=39), and MCAO plus treadmill exercise (n=28). The effects of aerobic exercise intervention on ischemic brain injury were evaluated using functional scoring, histological analysis, and Bio-Plex Protein Assays.

RESULTS

Early aerobic exercise intervention was found to improve motor function, prevent death of neuronal cells, and suppress the activation of microglial cells and astrocytes. Furthermore, it was observed that aerobic exercise downregulated the expression of the cytokine interleukin-1β and the chemokine monocyte chemotactic protein-1 after transient MCAO in experimental rats.

CONCLUSION

This study demonstrates that treadmill exercise rehabilitation promotes neuroprotection against cerebral ischemia-reperfusion injury via the downregulation of proinflammatory mediators.

Anti-Neuroinflammatory Effects of Uncaria sinensis in LPS-Stimulated BV2 Microglia Cells and Focal Cerebral Ischemic Mice

Uncaria sinensis (US) has long been used as a traditional Korean medicine to treat cardiovascular and central nervous system diseases, including hypertension and cerebral ischemia. Several recent studies have indicated that US has neuroprotective and cerebrovascular protective effects in ischemic brain injury; however, little is known about the anti-inflammatory effects of US. Therefore, the present study was designed to validate the anti-inflammatory effects of US. The anti-neuroinflammatory properties of US on pro-inflammatory mediators were investigated in lipopolysaccharide (LPS)-stimulated murine BV2 microglia and injured brains induced by photothrombotic cortical ischemia. Hexane extracts of US (HEUS) significantly suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated BV2 microglia and inhibited LPS-induced expression of iNOS and COX-2 in a dose-dependent manner without causing cytotoxicity in BV2 cells. In addition, HEUS significantly reduced the generation of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. Moreover, HEUS treatment inhibited the transcriptional activity and nuclear translocation of NF-κB in LPS-stimulated BV2 cells. In an in vivo study, treatment of HEUS resulted in significantly reduced infarct volume and improved neurological function 48 h after ischemic brain injury, possibly through the inhibition of the production of pro-inflammatory cytokines. HEUS inhibits LPS-stimulated production of pro-inflammatory mediators and prevents cerebral ischemic damage, suggesting that US may have therapeutic potential for the prevention and treatment of ischemic stroke accompanied by microglia activation.

Fractalkine Receptor Deficiency Is Associated with Early Protection but Late Worsening of Outcome following Brain Trauma in Mice

An impaired ability to regulate microglia activation by fractalkine (CX3CL1) leads to microglia chronic sub-activation. How this condition affects outcome after acute brain injury is still debated, with studies showing contrasting results depending on the timing and the brain pathology. Here, we investigated the early and delayed consequences of fractalkine receptor (CX3CR1) deletion on neurological outcome and on the phenotypical features of the myeloid cells present in the lesions of mice with traumatic brain injury (TBI). Wild type (WT) and CX3CR1(-/-) C57Bl/6 mice were subjected to sham or controlled cortical impact brain injury. Outcome was assessed at 4 days and 5 weeks after TBI by neuroscore, neuronal count, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Compared with WT mice, CX3CR1(-/-) TBI mice showed a significant reduction of sensorimotor deficits and lower cellular damage in the injured cortex 4 days post-TBI. Conversely, at 5 weeks, they showed a worsening of sensorimotor deficits and pericontusional cell death. Microglia (M) and macrophage (μ) activation and polarization were assessed by quantitative immunohistochemistry for CD11b, CD68, Ym1, and inducible nitric oxide synthase (iNOS)-markers of M/μ activation, phagocytosis, M2, and M1 phenotypes, respectively. Morphological analysis revealed a decreased area and perimeter of CD11b(+) cells in CX3CR1(-/-) mice at 4 days post-TBI, whereas, at 5 weeks, both parameters were significantly higher, compared with WT mice. At 4 days, CX3CR1(-/-) mice showed significantly decreased CD68 and iNOS immunoreactivity, while at 5 weeks post-injury, they showed a selective increase of iNOS. Gene expression on CD11b(+) sorted cells revealed an increase of interleukin 10 and insulin-like growth factor 1 (IGF1) at 1 day and a decrease of IGF1 4 days and 5 weeks post-TBI in CX3CR1(-/-), compared with WT mice. These data show an early protection followed by a chronic exacerbation of TBI outcome in the absence of CX3CR1. Thus, longitudinal effects of myeloid cell manipulation at different stages of pathology should be investigated to understand how and when their modulation may offer therapeutic chances.

Interleukin-1β transfer across the blood-brain barrier in the ovine fetus

Pro-inflammatory cytokines contribute to hypoxic-ischemic brain injury. Blood-brain barrier (BBB) dysfunction represents an important component of hypoxic-ischemic brain injury in the fetus. Hypoxic-ischemic injury could accentuate systemic cytokine transfer across the fetal BBB. There has been considerable conjecture suggesting that systemic cytokines could cross the BBB during the perinatal period. Nonetheless, evidence to support this contention is sparse. We hypothesized that ischemia-reperfusion increases the transfer of systemic interleukin-1β (IL-1β) across the BBB in the fetus. Ovine fetuses at 127 days of gestation were studied 4 hours after 30 minutes of bilateral carotid artery occlusion and compared with a nonischemic group. Recombinant ovine IL-1β protein was expressed from an IL-1β pGEX-2 T vector in E. coli BL-21 cells and purified. The BBB function was quantified in 12 brain regions using a blood-to-brain transfer constant with intravenous (125)I-radiolabeled IL-1β ((125)I-IL-1β). Interleukin-1β crossed the intact BBB in nonischemic fetuses. Blood-to-brain transport of (125)I-IL-1β was higher (P<0.05) across brain regions in fetuses exposed to ischemia-reperfusion than nonischemic fetuses. We conclude that systemic IL-1β crosses the intact fetal BBB, and that ischemia-reperfusion increases transfer of this cytokine across the fetal BBB. Therefore, altered BBB function after hypoxia-ischemia facilitates entry of systemic cytokines into the brain of the fetus.

Chloral Hydrate Preconditioning Protects Against Ischemic Stroke via Upregulating Annexin A1

AIMS

Preconditioning is promising for treating cerebral ischemic stroke. Annexin A1 (ANXA1) is a homeostatic antiinflammatory mediator that participates in countering against ischemic injuries. We investigated whether chloral hydrate preconditioning (CH) exerts neuroprotection via regulation of ANXA1 in stroke.

METHODS

Adult male C57BL/6J mice or ANXA1 knockout (ANXA1(-/-) ) mice were randomly allocated to control (NCH) and CH groups [2%, 6%, and 10% chloral hydrate (i.p.) 1 h before the middle cerebral artery occlusion (MCAO)]. Neurological performances were evaluated by modified 7-point neurological scales and rotarod test. Cerebral infarction was analyzed by triphenyltetrazolium chloride (TTC) staining and MRI. The expression of ANXA1, pro-inflammatory (TNF-α, IL-1β, IL-6), and antiinflammatory (IL-4, IL-10, TGF-β) cytokines was investigated by RT-PCR, western blot, and immunofluorescence.

RESULTS

Chloral hydrate preconditioning significantly improved the neurological outcomes and reduced the infarction and brain edema after ischemia. In addition, CH increased the expression of ANXA1 in the microglia, decreased the levels of TNF-α, IL-1β, and IL-6, while elevated the levels of IL-4, IL-10, and TGF-β in the MCAO mice. Furthermore, both ANXA1 blocker Boc1 (5 mg/kg, i.c.v.) or ANXA1 gene deficiency restrained the protective effects of CH against stroke.

CONCLUSIONS

Chloral hydrate preconditioning protects against ischemic injuries through upregulating the expression of ANXA1, and the followed antiinflammatory mechanisms.

Wharton's jelly derived mesenchymal stromal cells: Biological properties, induction of neuronal phenotype and current applications in neurodegeneration research

Multipotent mesenchymal stromal cells, also known as mesenchymal stem cells (MSC), can be isolated from bone marrow or other tissues, including fat, muscle and umbilical cord. It has been shown that MSC behave in vitro as stem cells: they self-renew and are able to differentiate into mature cells typical of several mesenchymal tissues. Moreover, the differentiation toward non-mesenchymal cell lineages (e.g. neurons) has been reported as well. The clinical relevance of these cells is mainly related to their ability to spontaneously migrate to the site of inflammation/damage, to their safety profile thanks to their low immunogenicity and to their immunomodulation capacities. To date, MSCs isolated from the post-natal bone marrow have represented the most extensively studied population of adult MSCs, in view of their possible use in various therapeutical applications. However, the bone marrow-derived MSCs exhibit a series of limitations, mainly related to their problematic isolation, culturing and use. In recent years, umbilical cord (UC) matrix (i.e. Wharton's jelly, WJ) stromal cells have therefore emerged as a more suitable alternative source of MSCs, thanks to their primitive nature and the easy isolation without relevant ethical concerns. This review seeks to provide an overview of the main biological properties of WJ-derived MSCs. Moreover, the potential application of these cells for the treatment of some known dysfunctions in the central and peripheral nervous system will also be discussed.