PRIM2: A Marker of MYC-driven Hyper-proliferation, Disease Progression, Tumor Aggressiveness and Poor Survival in Glioma Patients.

BACKGROUND/AIM: Gliomas are the most prevalent brain tumors with metabolic alterations playing a pivotal role in disease progression. However, the precise coordination of metabolic alterations with tumor-promoting cellular mechanisms, leading to tumor initiation, progression, and aggressiveness, resulting in poor outcomes, remains poorly understood in gliomas. MATERIALS AND METHODS: We conducted a metabolism-targeted differential gene expression analysis using glioma patients' expression profiling data from The Cancer Genome Atlas (TCGA) database. In addition, pathway enrichment analysis, gene set enrichment analysis (GSEA), transcription factor prediction, network construction, and correlation analyses were performed. Survival analyses were performed in R. All results were validated using independent GEO expression datasets. RESULTS: Metabolism-targeted analysis identified 5 hits involved in diverse metabolic processes linking them to disease aggressiveness in gliomas. Subsequently, we established that cell cycle progression and hyper-proliferation are key drivers of tumor progression and aggressiveness in gliomas. One of the identified metabolic hits, DNA primase 2 (PRIM2), a gene involved in DNA replication was found directly associated with cell cycle progression in gliomas. Furthermore, our analysis indicated that PRIM2, along with other cell cycle-related genes, is under the control of and regulated by the oncogenic MYC transcription factor in gliomas. In addition, PRIM2 expression alone is enough to predict MYC-driven cell cycle progression and is associated with tumor progression, aggressive disease state, and poor survival in glioma patients. CONCLUSION: Our findings highlight PRIM2 as a marker of MYC-driven cell cycle progression and hyper-proliferation, disease onset and progression, tumor aggressiveness, and poor survival in glioma patients.

Four-dimensional digital subtraction angiography to assess cerebral arteriovenous malformations.

BACKGROUND AND PURPOSE: The performance of a novel prototype four-dimensional (4D) digital subtraction angiography (DSA) for cerebral arteriovenous malformation (AVM) diagnosis was evaluated and compared with that of two-dimensional (2D) and three-dimensional (3D) DSA. METHODS: In this retrospective study, 37 consecutive cerebral AVM patients were included. The standard diagnostic results were concluded from the 2D and 3D DSA. Two 4D DSA volumes were reconstructed for each patient by a commercial and a prototype software, then evaluated by two independent experienced neurosurgeons, who were blinded to the diagnosis and treatment process. The evaluation results were compared with the diagnostic results on Spetzler-Martin (SM) Grading Scale, number of feeding arteries, number of draining veins, and intranidal aneurysms. RESULTS: Complete agreement was achieved between 4D DSA and 2D and 3D DSA in SM Grading Scale and intracranial aneurysm identification (agreement coefficient: 1) for both reviewers. The agreement coefficients were .888 and .917 for both reviewers in feeding artery number determination using 4D DSA product and 4D DSA prototype, respectively. The agreement coefficients in draining vein number determination were all larger than .94 for both reviewers using both 4D DSA volumes. CONCLUSIONS: The performance of this prototype 4D DSA in cerebral AVMs diagnosis was largely equivalent to that of 2D and 3D DSA combination. Four-dimensional DSA can be regarded as a very good complement for 2D DSA in cerebral AVM diagnosis.

Use of covered stents to treat complex cerebrovascular diseases: Expert consensus.

The treatment of complex cerebrovascular diseases (CCVDs) at the skull base, such as complex intracranial aneurysms, carotid-cavernous sinus fistulas, and intracranial artery traumatic injuries, is a difficult clinical problem despite advances in endovascular and surgical therapies. Covered stents or stent graft insertion is a new concept for endovascular treatment that focuses on arterial wall defect reconstruction, differing from endovascular lesion embolization or flow diverter therapies. In recent years, covered stents specifically designed for cerebrovascular treatment have been applied in the clinical setting, allowing thousands of patients with CCVDs to undergo intraluminal reconstruction treatment and achieving positive results, even in the era of flow diverters. Since there is no unified reference standard for the application of covered stents for treating CCVDs, it is necessary to further standardize and guide the clinical application of this technique. Thus, we organized authoritative experts in the field of neurointervention in China to write an expert consensus, which aims to summarize the results of covered stent insertion in the treatment of CCVDs and propose suitable standards for its application in the clinical setting. Based on the contents of this consensus, clinicians can use individualized intraluminal reconstruction treatment techniques for patients with CCVDs.

Biomechanical evaluation of the craniovertebral junction after odontoidectomy with anterior C1 arch preservation: A finite element study.

OBJECTIVE: Odontoidectomy with preservation of the anterior C1 arch can be increasingly achieved by an endoscopic endonasal approach. It is controversial whether preservation of the anterior C1 arch after odontoidectomy can prevent instability of the craniovertebral junction （CVJ） and avoid posterior fixation. The aim of this research was to investigate the biomechanical effect of the preserved anterior C1 arch after odontoidectomy. METHODS: A validated finite element model of a whole cervical spine (occipital bone to T1) was constructed to study the biomechanical changes due to traditional odontoidectomy (TO) and odontoidectomy with preservation of the anterior C1 arch (OPC1). RESULTS: The greatest biomechanical changes in the cervical spine model after TO and OPC1 occurred at C0-C1 and C1-C2. At C0-C1 and C1-C2, the motion changes of the TO and OPC1 models had no significant difference in flexion, extension and lateral bending. Compared with the intact model, motion increases of the two surgical models were both extremely significant at C1-C2 in extension (128.2% vs. 128.1%) and lateral bending (178% vs. 156%). In axial rotation, the TO approach produced more motions than the OPC1 approach, especially at C1-C2(90.3° under TO approach, and 74.6° under OPC1 approach). CONCLUSIONS: Preservation of the anterior C1 arch after odontoidectomy can preserve the axial rotational motion at C0-C1 and C1-C2, whereas the motions in extension and lateral bending continue to have an extremely abnormal increase at C1-C2. Thus, instability of the CVJ still exists, and posterior internal fixation may also be required after OPC1.

The Clinical Efficacy Analysis of Treatment With a Willis Covered Stent in Traumatic Pseudoaneurysm of the Internal Carotid Artery.

Objective: To investigate the safety and efficacy of Willis covered stents (WCS) in the treatment of traumatic pseudoaneurysm of the cranial internal carotid artery (CICA). Methods: Fifteen patients with traumatic pseudoaneurysm of the intracranial segment of the ICA treated with the WCS system at our institution from 2013 to 2019 were analyzed retrospectively. Follow-up observation and digital subtraction angiography (DSA) examination were conducted ~6 months after the treatment. Results: DSA performed immediately after stent deployment revealed that complete occlusion of the lesion was achieved in 13 patients and that endoleak occurred in two patients. In 12 patients, postoperative DSA examination indicated that the lesions were completely occluded. In two patients who had a second stent implantation at the break of the ICA, traumatic ICA rupture was essentially completely obstructed in 1 patient. The endoleak remained in one patient with carotid cavernous sinus fistula because the placement of the second stent system was difficult with his ICA tortuosity. No recurrence of aneurysms, hemorrhage, or other lesions was observed, and the patients' parent arteries were patent without stenosis. No procedure-related complications or ischemic strokes occurred during the follow-up period of ~6 months. Conclusions: For treatment of traumatic pseudoaneurysm of the CICA, Willis covered stent implantation in some appropriate cases, is safe and effective. However, large-sample controlled studies and multicenter studies are needed for further confirmation.

Effects of Primary Decompressive Craniectomy on the Outcomes of Serious Traumatic Brain Injury with Mass Lesions, and Independent Predictors of Operation Decision.

BACKGROUND: Although operative indications for traumatic brain injury (TBI) are known, neurosurgeons are unsure whether to remove the bone flap after mass lesion extraction, and an efficient scoring system for predicting which patients should undergo decompressive craniectomy (DC) does not exist. METHODS: Nine parameters were assessed. In total, 245 patients with severe TBI were retrospectively assessed from June 2015 to May 2019, who underwent DC or craniotomy to remove mass lesions. The 6-month mortality and Extended Glasgow Outcome Scale scores were compared between the DC and craniotomy groups. Using univariable and multivariable logistic regression equations, receiver operating characteristic curves were obtained for predicting the decision for DC. RESULTS: The overall 6-month mortality in the entire cohort was 11.43% (28/245). Patients undergoing DC had lower mean preoperative Glasgow Coma Scale scores (P = 0.01), and higher amounts of individuals with a Glasgow Coma Scale score of 6 (P = 0.007), unresponsive pupillary light reflex (P < 0.001), closed basal cisterns (P < 0.001), and diffuse injury (P = 0.025), compared with the craniotomy group. Because of high disease severity, individuals administered primary DC showed increased 6-month mortality compared with the craniotomy group. However, in surviving patients, favorable Extended Glasgow Outcome Scale rates were similar in both groups. Pupillary light reflex and basal cisterns were independent predictors of the DC decision. Based on receiver operating characteristic curves, the model had sensitivity and specificity of 81.6% and 84.9%, respectively, in predicting the probability of DC. CONCLUSIONS: These preliminary data showed that primary DC may benefit some patients with severe TBI with mass lesions. In addition, unresponsive preoperative pupil reaction and closed basal cistern could predict the DC decision.

Role of the stromal cell derived factor-1 in the biological functions of endothelial progenitor cells and its underlying mechanisms.

Stromal cell derived factor-1 (SDF-1) is a chemokine that plays a critical role in the homing of stem and progenitor cells, including endothelial progenitor cells (EPCs). However, little research has been undertaken to evaluate the roles of SDF-1 in the biological functions of EPCs and related signaling pathways. The present study aimed to investigate the biological functions of EPCs in response to SDF-1, as well as the underlying mechanisms. The effects of SDF-1 treatment on EPC proliferation, migration and tube formation were assessed by performing MTS, Transwell and in vitro tube formation assays, respectively. The phosphorylation status of Akt and ERK was evaluated by western blotting. The present results indicated that SDF-1 treatment enhanced EPC proliferation, migration and tube formation compared with the control group. Furthermore, SDF-1-induced EPC proliferation was significantly reduced following treatment with a C-X-C Motif Chemokine Receptor 4 antagonist (AMD3100), a PI3K inhibitor (LY294002) and the mitogen-activated protein kinase kinase inhibitor (MEK; PD98059). SDF-1-induced migration and angiogenesis were significantly suppressed by the PI3K inhibitor, but not the MEK inhibitor. Moreover, SDF-1 significantly increased the protein expression levels of phosphorylated (p)-Akt and p-ERK; however, SDF-1-induced effects on protein expression were suppressed by AMD3100, LY294002 and PD98059. Thus, SDF-1-induced EPC proliferation was mediated by activation of the Akt and ERK signaling pathways, whereas SDF-1-mediated EPC migration and tube formation only involved activation of the Akt signaling pathway.

Response Activation and Inhibition in Patients With Prolactinomas: An Electrophysiological Study.

Impairment of executive function has been reported in patients with prolactinomas. However, few studies have investigated the electrophysiological mechanisms of response activation and response inhibition in these patients. In this study, we employ an event-related potentials (ERPs) technique to quantitatively assess response activation and inhibition before and after the surgical treatment of prolactinomas. A 64-electrode electroencephalogram (EEG) skullcap was used to record the brain activity in 20 pre-operative patients, 20 follow-up post-operative patients, and 20 healthy controls (HCs) while performing the visual Go/Nogo task. As expected, we identified P300 across all study populations that could reflect response activation and inhibition. Across the three groups, the Nogo stimuli evoked larger frontal-central P300 than the Go stimuli did. In contrast, the Go trials elicited larger parietal P300 than the Nogo trials did. The peak latency of P300 was significantly delayed in both the pre-operative and the post-operative groups compared to the HCs. The amplitude of P300 in both the Go and the Nogo conditions was significantly decreased in the pre-operative patients compared with that of the HCs. At 6 months post-operatively, the prolactinoma patients showed an increase in amplitude of P300 during both the Go and the Nogo tasks. These findings indicate that the prolactinoma patients suffer from deficits in response activation and inhibition, which could be improved by surgical treatment.

Analysis of spinal angiograms that missed diagnosis of spinal vascular diseases with venous hypertensive myelopathy: the non-technical factors.

PURPOSE: Spinal DSA is the "gold standard" technique to identify the spinal vascular diseases with venous hypertensive myelopathy (VHM). However, sometimes spinal DSA can find nothing in patients with confirmed spinal vascular anomalies. Many of the reasons are avoidable technical factors. Nevertheless, there are also some non-technical factors. The objective of this study was to identify the non-technical factors. METHODS: The cause of the missed findings was found as the non-technical factors in 14 patients. The clinical records and radiological findings of the 14 patients were reviewed. RESULTS: The so-called standard spinal angiography can found nothing in the 14 patients. Additional angiography was performed and detected the lesions. Eight patients were found lesions supplied by carotid arteries or iliac arteries, including 2 cranial DAVF with internal carotid artery blood supply, 3 cranial DAVF with external carotid artery blood supply and 2 pelvic AVF with internal iliac artery blood supply and 1 pelvic AVM with internal iliac artery blood supply. Six patients were caused by stenosis of spinal draining vein, including 3 stenosis of the third lumbar veins and 3 stenosis of left renal veins combined with the reno-spinal trunk. CONCLUSIONS: In order to avoid the missed findings of spinal vascular diseases with VHM, the technical factors should be reduced by performing a rigorous comprehensive angiography. To reduce the non-technical factors, the angiography of the internal iliac artery, the carotid artery systems and spinal draining veins should be performed in some special cases if the routine spinal angiography can find nothing.

Correction: Opposing Effects of PI3K/Akt and Smad-Dependent Signaling Pathways in NAG-1-Induced Glioblastoma Cell Apoptosis.

[This corrects the article DOI: 10.1371/journal.pone.0096283.].

Long non-coding RNA MEG3 regulates proliferation, apoptosis, and autophagy and is associated with prognosis in glioma.

PURPOSE: Accumulating evidence indicates that dysregulated long noncoding RNAs (lncRNAs) play critical roles in tumorigenesis and cancer progression. LncRNA-maternally expressed gene 3 (MEG3) has been shown to be involved in the initiation and development of several cancers, including glioma. However, the clinical prognostic value of MEG3 in glioma has not yet been fully elucidated. METHODS: The expression levels of MEG3 were detected in 79 glioma tissues and adjacent normal brain tissues, as well as, glioma cells and normal human astrocytes by qRT-PCR. Kaplan-Meier and Cox regression methods were utilized for the survival analysis. MTT assay, flow cytometry, and immunofluorescence assay were carried out to detect the impact of MEG3 on glioma cell proliferation, apoptosis, and autophagy. RESULT: The current results showed that MEG3 expression was significantly downregulated in glioma tissues and cell line and negatively correlated with WHO grade in glioma patients. Low MEG3 expression was significantly associated with the advanced WHO grade, low Karnofsky performance score (KPS), IDH wild-type, and tumor recurrence. Patients displaying a low expression of MEG3 contributed to poor overall survival. The downregulated level of MEG3, advanced WHO grade, low KPS, IDH wild-type, and tumor recurrence were independent poor prognostic indicators in glioma patients. The in vitro experiments demonstrated that the MEG3 overexpression remarkably suppressed the proliferation while facilitating apoptosis and autophagy in glioma cells. CONCLUSIONS: These findings indicated a critical role of MEG3 in glioma cell proliferation, apoptosis, and autophagy. Also, the gene was found to be significantly associated with the prognosis in glioma patients. Thus, it might provide a new target for predicting prognosis and therapeutic intervention in glioma.

Treatment strategies for traumatic cervico-cranial pseudoaneurysms: A single institution experience.

AIM: Limited clinical and angiographic data exists for patients with traumatic cervico-cerebral pseudoaneurysms. In this paper, we present our limited experience with various management strategies for traumatic cervico-cranial pseudoaneurysms. MATERIALS AND METHODS: We retrospectively analyzed 37 consecutive cases of traumatic pseudoaneurysms involving the cervico-cranial or the cerebral arteries diagnosed at our center from September 2009 to December 2014. The demographic data, etiology, clinical presentation, lesion location, treatment modality, and follow-up outcomes of these patients were reviewed. Among these 37 patients, 5 patients were treated by surgery, while 29 patients were treated by the endovascular approach and 3 received conservative treatment. RESULTS: During the study period, 42 pseudoaneurysms were identified in 37 patients with a history of head or neck injury. Five patients underwent surgical exploration of the lesion with an uneventful postoperative course. Twenty-nine patients were treated by endovascular interventions with various embolization materials including coils, stents, detachable balloons, liquid embolic agents, and a combination of these agents. The angiographic follow-up imaging demonstrated complete exclusion of the aneurysm from the circulation with the patient being free from any additional neurological deficits. CONCLUSION: Proper selection of an appropriate approach is essential to address the management of traumatic cervico-cerebral pseudoaneurysms. The treatment of traumatic cervico-cerebral pseudoaneurysms should be selected according to the location and the clinical features of the pseudoaneurysms. The endovascular treatment is a safe and effective modality and should be the first-line choice for treatment of traumatic pseudoaneurysms.

Malva Sylvestris Attenuates Cognitive Deficits in a Repetitive Mild Traumatic Brain Injury Rat Model by Reducing Neuronal Degeneration and Astrocytosis in the Hippocampus.

BACKGROUND The aim of our study was to evaluate the effect of Malva sylvestris (MS) on cognitive dysfunction in a repetitive mild traumatic brain injury (MTBI). MATERIAL AND METHODS MTBI was induced in all the study animals by hitting a metallic pendulum near the parietal-occipital area of the skull three times a day for ten days. Animals were treated with MS (250 mg/kg and 500 mg/kg) intragastrically per day for seven consecutive days. Cognitive function was estimated by the Morris water maze (MWM) method. Histopathology studies were performed on the hippocampal region by Nissl staining and anti GFAP staining. Concentrations of reactive oxygen species (ROS), and oxidative parameters including superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO), and inflammatory cytokines in the brain tissues were measured. RESULTS Treatment with MS significantly improved cognitive function compared to the negative control. Histopathology studies suggested that treatment with MS significantly decreased (p<0.01) the count of neurodegenerative cells and induction of astrocytosis in the MTBI treated group compared to the negative control group. However, the concentrations of ROS and LPO, and the activities of SOD and CAT were significantly decreased in the MS treated groups of MTBI rats compared to the negative control group. Inflammatory cytokines, such as IL-1ß, IL6, and TNF-α were significantly decreased (p<0.01) in the brain tissues of the MTBI treated group compared to the control group of rats. CONCLUSIONS This study concluded that treatment with MS significantly improved cognitive dysfunction by reducing neurodegeneration and astrocytosis in brain tissues via decreasing oxidative stress and inflammation in neuronal cells.

Association between angiotensin-converting enzyme insertion/deletion polymorphisms and intracranial aneurysm susceptibility: A meta-analysis.

Various studies have evaluated the association between polymorphisms of angiotensin-converting enzyme (ACE) and intracranial aneurysm (IA) risk; however, the results remain inconsistent. The PubMed, Embase, and Wanfang Data databases were systematically searched until January 6th 2016. Case-control studies investigating the association between the ACE polymorphism and IA risk were included. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with the fixed or random-effects model assuming allele, homozygote comparison of codominant, heterozygote comparison of codominant, dominant, and recessive models. Seven studies including 1,074 cases and 1,500 controls were included in the current meta-analysis. The results of the analysis indicated that the ACE polymorphism significantly increased IA risk in the allele, homozygote comparison of codominant and dominant models. According to the further stratified analysis by ethnicity, source of control and sample sizes, a significant association was identified between the ACE variant and IA risk in Asian individuals, hospital-based, or large (>300) subgroups in all of the genetic models, not including the recessive model. Furthermore, no significantly increased risk was indicated in Caucasian individuals, population-based, or small (<300) subgroups in the heterozygote comparison of codominant, dominant and recessive models. The available evidence indicates that the ACE polymorphism is associated with an increased risk of IA, particularly in Asian individuals. However, other factors may impact this association. Further large, well-designed multicenter studies are required to validate the findings from the present study.

Endovascular Coiling Versus Microsurgical Clipping for Patients With Ruptured Very Small Intracranial Aneurysms: Management Strategies and Clinical Outcomes of 162 Cases.

BACKGROUND: Treatments for intracranial aneurysms mainly include endovascular treatment and craniotomy. Most studies report on large intracranial aneurysms, yet treatments for very small intracranial aneurysms remain controversial. Our purpose was to explore management strategies for ruptured very small intracranial aneurysms. METHODS: From January 2002 to September 2010, 162 consecutive patients with ruptured very small intracranial aneurysms (≤3 mm) were retrospectively analyzed by comparing procedural data, adverse events, additional procedures, and length of hospital stay between management strategies. Modified Rankin Scale was assessed at 2 months and at 1 year by a postal questionnaire and telephone interview. RESULTS: Of the 85 patients in the microsurgical group, 79 underwent surgical clipping and 6 underwent wrapping; 77 patients underwent endovascular therapy (endovascular group), including coiling (65 cases), stent-assisted (13 cases) and balloon-assisted (7 cases) coiling, and stenting (2 cases). At 2 months, a good grade (modified Rankin Scale 0-2) was achieved in 74% of patients in the endovascular group and 69.4% of patients in the microsurgical group. At 1 year, a good grade was achieved by 84.9% in the endovascular group and 80% in the microsurgical group. Logistic regression results showed that whichever treatment option was chosen, Hunt-Hess grade, age, cerebral vasospasm, and complications contributed significantly to the prediction of outcome at 2 months. CONCLUSIONS: Endovascular therapy for ruptured very small intracranial aneurysms was not inferior to surgical clipping and showed a slight trend toward better prognosis.

14-3-3zeta Positive Cells Show More Tumorigenic Characters in Human Glioblastoma.

AIM: Expression of 14-3-3zeta is upregulated in many cancer types and plays an important role in tumorigenesis. Our previous studies have shown that 14-3-3zeta has a positive expression and is associated with a poor prognosis in patients with glioblastoma. In this study, we investigated whether 14-3-3zeta positive cells show more tumorigenic character and stronger chemotherapy resistance. MATERIAL AND METHODS: Six human glioblastoma cells lines were derived from the 6 patients with tumor, and the cells were sorted by 14-3-3zeta expression. The cell viability, invasion, tumorigenic ability and chemotherapy resistance were compared between the 14-3-3 positive and negative expression groups. RESULTS: 14-3-3zeta positive cells displayed oncogenic properties, more tumorigenic character, high invasiveness, tumorsphere formation ability and resistance to temozolomide chemotherapy treatment. CONCLUSION: Cells with 14-3-3zeta positive expression show more tumorigenic character and should be administered other treatments in the future.

Hyperbaric Oxygen Intervention Modulates Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats: Possible Involvement of TLR4/NF-x03BA; B-Mediated Signaling Pathway.

BACKGROUND/AIMS: Previous studies have proved that the activation of TLR4/NF-x03BA; B signaling pathway is involved in inflammatory processes in early brain injury (EBI) after subarachnoid hemorrhage (SAH). Hyperbaric oxygen (HBO) intervention has successfully been used to treat several animal models of tissue injury via its anti-inflammation property. This study was undertaken to investigate the influence of HBO administration on the TLR4/NF-x03BA; B signaling pathway in rats at the early stage of SAH. METHODS: Male Sprague-Dawley rats (n = 150) were randomly divided into 5 groups: the sham, the sham + 2.8 atmospheres absolute (ATA) HBO group, the SAH group, the SAH + 2.0ATA HBO group, the SAH + 2.8ATA HBO group. Each group (n = 30) was randomly subdivided into three subgroups that were examined at the following time points: 24 h, 48 h and 72 h post-injury. HBO (100% O2, 2.0ATA or 2.8ATA for 90mins) was initiated 12 h after injury. Neurological deficit, brain edema and blood-brain barrier (BBB) permeability were assessed to evaluate the development of EBI. The expressions of TLR4, NF-x03BA; B and pro-inflammatory cytokines in the cortical were determined by real time polymerase chain reaction (RT-PCR), western blot, immunohistochemistry, or enzyme-linked immunosorbent assay (ELISA). RESULTS: Our study showed that treatment with HBO significantly decreased the expressions of TLR4, NF-x03BA; B and the downstream inflammatory agents, such as TNF-α, IL-6, IL-1ß and ICAM-1, and also improved brain edema, blood-brain barrier permeability and neurologic function. CONCLUSIONS: These findings indicate that HBO treatment may result in abatement of the development of EBI after SAH, possibly through suppression of TLR4/NF-x03BA; B signaling pathway.

GPER1 mediates estrogen-induced neuroprotection against oxygen-glucose deprivation in the primary hippocampal neurons.

It is well-known that the neuroprotective effects of estrogen have potential in the prevention and amelioration of ischemic and degenerative neurological disorders, while the underlying mechanisms for estrogen actions are undefined. As an important mediator for the non-genomic functions of estrogen, GPER1 (G Protein-coupled Estrogen Receptor 1) has been suggested to involve in the beneficial roles of estrogen in neural cells. Here our studies on primary hippocampal neurons have focused on GPER1 in an in vitro model of ischemia using oxygen-glucose deprivation (OGD). GPER1 expression in the primary hippocampal neurons was stimulated by the OGD treatments. Both E2 (estradiol) and E2-BSA (membrane impermeable estradiol by covalent conjugation of bovine serum albumin) attenuated OGD-induced cell death in primary cultures of hippocampal neurons. Importantly, this membrane-mediated estrogen function requires GPER1 protein. Knocking down of GPER1 diminished, while overexpression of GPER1 potentiated, the protective roles of E2/E2-BSA following OGD. Additionally, the downstream mechanisms employed by membrane-associated estrogen signaling were found to include PI3K/Akt-dependent Ask1 inhibition in the primary hippocampal neurons. Overall, these research results could enhance our understanding of the neuroprotective actions for estrogen, and provide a new therapeutic target for improving stroke outcome and ameliorating degenerative neurological diseases.

GPER expressed on microglia mediates the anti-inflammatory effect of estradiol in ischemic stroke.

BACKGROUND: Stroke could lead to serious morbidity, of which ischemic stroke counts for majority of the cases. Inflammation plays an important role in the pathogenesis of ischemic stroke, thus drugs targeting inflammation could be potentially neuroprotective. Estradiol was shown to be neuroprotective as well as anti-inflammatory in animal models of ischemic stroke with unclear mechanism. We hypothesize that the anti-inflammatory and neuroprotective effect of estradiol is mediated by the estradiol receptor G protein-coupled estrogen receptor 1 (GPER) expressed on microglia. METHODS: We have generated the rat global cerebral ischemic model and the primary microglia culture to study the neuroprotective and anti-inflammatory effect of estradiol. We have further used pharmacological methods and siRNA knockdown approach to study the underlying mechanism. RESULTS: We found that estradiol reduced the level of proinflammatory cytokines including IL-1ß and TNF-α, both in vivo and in vitro. We also found that the specific GPER agonist G1 could reduce the level of IL-1ß (P = 0 P = 0.0017, one-way ANOVA and post hoc test) and TNF-α (P < 0.0001) in the primary microglia culture. Moreover, the specific GPER antagonist G15 was able to abolish the anti-inflammatory effect of estradiol. Estradiol failed to reduce the level of IL-1ß (P = 0.4973, unpaired Student's t-test) and TNF-α (P = 0.1627) when GPER was knocked down. CONCLUSIONS: Our studies have suggested that GPER expressed on microglia mediated the anti-inflammatory effect of estradiol after ischemic stroke. Our studies could potentially help to develop more specific drugs to manage inflammation postischemic stroke.

Functional response of cerebral blood flow induced by somatosensory stimulation in rats with subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is often accompanied by cerebral vasospasm (CVS), which is the phenomenon of narrowing of large cerebral arteries, and then can produce delayed ischemic neurological deficit (DIND) such as lateralized sensory dysfunction. CVS was regarded as a major contributor to DIND in patients with SAH. However, therapy for preventing vasospasm after SAH to improve the outcomes may not work all the time. It is important to find answers to the relationship between CVS and DIND after SAH. How local cerebral blood flow (CBF) is regulated during functional activation after SAH still remains poorly understood, whereas, the regulation of CBF may play an important role in weakening the impact of CVS on cortex function. Therefore, it is worthwhile to evaluate the functional response of CBF in the activated cortex in an SAH animal model. Most evaluation of the effect of SAH is presently carried out by neurological behavioral scales. The functional imaging of cortical activation during sensory stimulation may help to reflect the function of the somatosensory cortex more locally than the behavioral scales do. We investigated the functional response of CBF in the somatosensory cortex induced by an electrical stimulation to contralateral forepaw via laser speckle imaging in a rat SAH model. Nineteen Sprague-Dawley rats from two groups (control group, n=10 and SAH group, n=9) were studied. SAH was induced in rats by double injection of autologous blood into the cisterna magna after CSF aspiration. The same surgical procedure was applied in the control group without CSF aspiration or blood injection. Significant CVS was found in the SAH group. Meanwhile, we observed a delayed peak of CBF response in rats with SAH compared with those in the control group, whereas no significant difference was found in magnitude, duration, and areas under curve of relative CBF changes between the two groups. The results suggest that the regulation function of local CBF during functional activation induced by somatosensory stimulation might not be seriously impaired in the somatosensory cortex of rats with SAH. Therefore, our findings might help to understand the clinical phenomenon that DIND might not occur even when CVS was found in SAH patients.