Selective Activation of G Protein-Coupled Estrogen Receptor 1 (GPER1) Reduces ER Stress and Pyroptosis via AMPK Signaling Pathway in Experimental Subarachnoid Hemorrhage.

Neuroinflammation is a critical pathogenic event following hemorrhagic stroke. Endoplasmic reticulum (ER) stress-induced apoptosis and nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3(NLRP3)-associated pyroptosis can contribute to the escalation of neuroinflammatory responses, leading to increased brain damage. G protein-coupled estrogen receptor 1(GPER1), as the most extensively characterized brain-derived estrogen, was reported to trigger neuroprotective effects. However, the anti-apoptotic and anti-pyroptotic effect of GPER1 activation and the underlying mechanism has not been fully elucidated. We established the experimental SAH model by intravascular perforation. The GPER1 selective agonist G1 was intravenously administered 1 h following SAH. For mechanistic exploration, the selective inhibitor of adenosine monophosphate-activated protein kinase (AMPK), dorsomorphin, was administered via intracerebroventricular injection 30 min prior to SAH induction. Post-SAH assessments included SAH grade, the short-term and long-term neurological outcomes, brain edema, cerebral blood flow, transmission electron microscopy (TEM), western blot (WB), ELISA, TUNEL staining, Fluoro-Jade C staining (FJC), and immunofluorescence staining. The expression of GPER1 was observed to elevate at 6 h and peaked at 24 h subsequent to SAH, predominantly co-localized with neurons. Post-treatment with G1 markedly ameliorated both the short-term and long-term neurological deficits of SAH mouse, as well as inhibiting the expression of neuronal ER stress-associated apoptotic proteins (i.e., CHOP, GRP78, Caspase-12, Cleaved Caspase-3, Bax, Bcl2) and pyroptosis-associated proteins (i.e., NLRP3, ASC, Cleaved Caspase-1). Additionally, our research revealed that inhibition of AMPK with dorsomorphin attenuated the neuroprotective effects of G1. This was accompanied by modifications in the molecular pathways associated with ER stress-induced apoptosis and pyroptosis. These data herein elucidated that GPER1 exerted neuroprotective effects by mitigating neuroinflammation in an AMPK-dependent manner, which modulates neuronal ER stress-associated apoptosis and pyroptosis. Boosting the anti-apoptotic and anti-pyroptotic effect by activating GPER1 may be an efficient treatment strategy for SAH patients.

ISRIB improves white matter injury following TBI by inhibiting NCOA4-mediated ferritinophagy.

Traumatic brain injury (TBI) often results in persistent neurological dysfunction, which is closely associated with white matter injury. The mechanisms underlying white matter injury after TBI remain unclear. Ferritinophagy is a selective autophagic process that degrades ferritin and releases free iron, which may cause ferroptosis. Although ferroptosis has been demonstrated to be involved in TBI, it is unclear whether ferritinophagy triggers ferroptosis in TBI. Integrated stress response inhibitor (ISRIB) has neuroprotective properties. However, the effect of ISRIB on white matter after TBI remains uncertain. We aimed to investigate whether ferritinophagy was involved in white matter injury following TBI and whether ISRIB can mitigate white matter injury after TBI by inhibiting ferritinophagy. In this study, controlled cortical impact (CCI) was performed on rats to establish the TBI model. Ferritinophagy was measured by assessing the levels of nuclear receptor coactivator 4 (NCOA4), which regulates ferritinophagy, ferritin heavy chain 1(FTH1), LC3, ATG5, and FTH1 colocalization with LC3 in the white matter. Increased NCOA4 and decreased FTH1 were detected in our study. FTH1 colocalization with LC3 enhanced in the white matter after TBI, indicating that ferritinophagy was activated. Immunofluorescence co-localization results also suggested that ferritinophagy occurred in neurons and oligodendrocytes after TBI. Furthermore, ferroptosis was assessed by determining free iron content, MDA content, GSH content, and Perl's staining. The results showed that ferroptosis was suppressed by NCOA4 knockdown via shNCOA4 lentivirus infection, indicating that ferroptosis in TBI is triggered by ferritinophagy. Besides, NCOA4 deletion notably improved white matter injury following TBI, implying that ferritinophagy contributed to white matter injury. ISRIB treatment reduced the occurrence of ferritinophagy in neurons and oligodendrocytes, attenuated ferritinophagy-induced ferroptosis, and alleviated white matter injury. These findings suggest that NCOA4-mediated ferritinophagy is a critical mechanism underlying white matter injury after TBI. ISRIB holds promise as a therapeutic agent for this condition.

Rasd1 is involved in white matter injury through neuron-oligodendrocyte communication after subarachnoid hemorrhage.

AIMS: Rasd1 has been reported to be correlated with neurotoxicity, metabolism, and rhythm, but its effect in case of subarachnoid hemorrhage (SAH) remained unclear. White matter injury (WMI) and ferroptosis participate in the early brain injury (EBI) after SAH. In this work, we have investigated whether Rasd1 can cause ferroptosis and contribute to SAH-induced WMI. METHODS: Lentivirus for Rasd1 knockdown/overexpression was administrated by intracerebroventricular (i.c.v) injection at 7 days before SAH induction. SAH grade, brain water content, short- and long-term neurobehavior, Western blot, real-time PCR, ELISA, biochemical estimation, immunofluorescence, diffusion tensor imaging (DTI), and transmission electron microscopy (TEM) were systematically performed. Additionally, genipin, a selective uncoupling protein 2(UCP2) inhibitor, was used in primary neuron and oligodendrocyte co-cultures for further in vitro mechanistic studies. RESULTS: Rasd1 knockdown has improved the neurobehavior, glia polarization, oxidative stress, neuroinflammation, ferroptosis, and demyelination. Conversely, Rasd1 overexpression aggravated these changes by elevating the levels of reactive oxygen species (ROS), inflammatory cytokines, MDA, free iron, and NCOA4, as well as contributing to the decrease of the levels of UCP2, GPX4, ferritin, and GSH mechanistically. According to the in vitro study, Rasd1 can induce oligodendrocyte ferroptosis through inhibiting UCP2, increasing reactive oxygen species (ROS), and activating NCOA4-mediated ferritinophagy. CONCLUSIONS: It can be concluded that Rasd1 exerts a modulated role in oligodendrocytes ferroptosis in WMI following SAH.

Establishment and multicenter external validation of a risk prediction model for de novo intracranial aneurysms based on a systematic review and meta-analysis of 19 cohorts.

OBJECTIVE: A de novo intracranial aneurysm (IA) is a second, new IA that develops in patients with IAs distant from where the initial IA was detected. This study aimed to identify risk factors for de novo IA formation and establish and externally validate a multicenter risk prediction model for de novo IAs. METHODS: A systematic review and meta-analysis of existing de novo IA cohorts was conducted to form the derivation cohort. The risk ratios and 95% CIs of each risk factor were calculated. In addition, risk scores included in the model were calculated based on the statistically significant risk factors with their weightings. Then the model was validated in a multicenter external cohort of Chinese patients, and receiver operating characteristic and calibration curves, decision curve analysis, and Kaplan-Meier curves were used to evaluate the model. RESULTS: Nineteen studies with 9351 patients, of whom 304 patients (3.25%) developed de novo IAs, were included in the derivation cohort. These patients developed de novo IAs at 2.5-18.5 years during a total follow-up of 3.3-18.8 years. The statistically significant risk factors were age < 60 years, female sex, smoking history, family history of IAs, multiple IAs at initial diagnosis, and initial IAs in the middle cerebral artery, with risk scores of 4, 5, 2, 6, 3, and 3, respectively. Then, a multicenter external cohort comprising 776 patients, of whom 45 patients (5.80%) developed de novo IAs, was included in the validation cohort. De novo IAs formed in these patients at a mean of 5.25 years during a mean follow-up of 6.19 years. The area under the curve of the model was 0.804, with a sensitivity of 0.667 and specificity of 0.900, at a cutoff value of 13. The calibration curve, decision curve analysis, and Kaplan-Meier curves also indicated good performance of the model. CONCLUSIONS: This prediction model is a convenient and intuitive tool for identifying high-risk patients with de novo IAs. Reasonable use of the model can not only aid in clinical decision-making but also play a positive role in the prevention of aneurysmal subarachnoid hemorrhage to a certain extent.

Neuropharmacological efficacy of metformin for stroke in rodents: A meta-analysis of preclinical trials.

Background: Stroke, including ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage (SAH), remains a leading cause of mortality globally. Different stroke subtypes have similar detrimental effects in multiple fields of health. Previous research has shown that metformin plays a neuroprotective role in experimental animal models of stroke; however, a preclinical quantitative analysis on the ability of metformin to treat stroke is still lacking. This meta-analysis evaluates the efficacy of metformin in improving stroke prognosis in rodent models of stroke. Methods: Relevant preclinical trials were retrieved from PubMed, EMBASE, and the Web of Science. The neurological score (NS), brain water content (BWC), infarct size, rotarod test, TUNEL, neuron quantity, microglia quantity, and p-AMPK levels were compared between a control group and a metformin group using the standardized mean difference (SMD) and corresponding confidence interval (CI). Quality was assessed with SYRCLE's risk of bias tool. Results: Fifteen articles published from 2010 to 2022 were included in the meta-analysis. The metformin group had statistically significant differences compared to the control group in the following aspects: NS (SMD -1.45; 95% CI -2.32, -0.58; p = 0.001), BWC (SMD -3.22; 95% CI -4.69, -1.76; p < 0.0001), infarct size (SMD -2.90; 95% CI -3.95, -1.85; p < 0.00001), rotarod test (SMD 2.55; 95% CI 1.87, 3.23; p < 0.00001), TUNEL (SMD -3.63; 95% CI -5.77, -1.48; p = 0.0009), neuron quantity (SMD 3.42; 95% CI 2.51, 4.34; p < 0.00001), microglia quantity (SMD -3.06; 95% CI -4.69, -1.44; p = 0.0002), and p-AMPK levels (SMD 2.92; 95% CI 2.02, 3.82; p < 0.00001). Furthermore, sensitivity analysis and stratified analysis were conducted for heterogeneous outcome indicators. Conclusion: Overall, metformin treatment improves severe outcomes triggered by stroke. Despite the limitations intrinsic to animal studies, this systematic review may provide a vital reference for future high-quality preclinical trials and clinical use.

Dexras1 Induces Dysdifferentiation of Oligodendrocytes and Myelin Injury by Inhibiting the cAMP-CREB Pathway after Subarachnoid Hemorrhage.

White matter damage (WMD), one of the research hotspots of subarachnoid hemorrhage (SAH), mainly manifests itself as myelin injury and oligodendrocyte differentiation disorder after SAH, although the specific mechanism remains unclear. Dexamethasone-induced Ras-related protein 1(Dexras1) has been reported to be involved in nervous system damage in autoimmune encephalitis and multiple sclerosis. However, whether Dexras1 participates in dysdifferentiation of oligodendrocytes and myelin injury after SAH has yet to be examined, which is the reason for creating the research content of this article. Here, intracerebroventricular lentiviral administration was used to modulate Dexras1 levels in order to determine its functional influence on neurological injury after SAH. Immunofluorescence, transmission electron microscopy, and Western blotting methods, were used to investigate the effects of Dexras1 on demyelination, glial cell activation, and differentiation of oligodendrocyte progenitor cells (OPCs) after SAH. Primary rat brain neurons were treated with oxyhemoglobin to verify the association between Dexras1 and cAMP-CREB. The results showed that Dexras1 levels were significantly increased upon in vivo SAH model, accompanied by OPC differentiation disturbances and myelin injury. Dexras1 overexpression significantly worsened OPC dysdifferentiation and myelin injury after SAH. In contrast, Dexras1 knockdown ameliorated myelin injury, OPC dysdifferentiation, and glial cell activation. Further research of the underlying mechanism discovered that the cAMP-CREB pathway was inhibited after Dexras1 overexpression in the in vitro model of SAH. This study is the first to confirm that Dexras1 induced oligodendrocyte dysdifferentiation and myelin injury after SAH by inhibiting the cAMP-CREB pathway. This present research may reveal novel therapeutic targets for the amelioration of brain injury and neurological dysfunction after SAH.

The therapeutic efficacy of resveratrol for acute lung injury-A meta-analysis of preclinical trials.

Background: Resveratrol (RES) has a protective effect on acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Our purpose was to conduct a meta-analysis to investigate the efficacy of RES for ALI/ARDS in animal models. Methods: PubMed, EMBASE and Web of Science were searched to screen relevant preclinical trials. The standardized mean difference (SMD) was used to compare the lung injury score, lung wet-dry weight ratio (W/D ratio), tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-10, the number of neutrophils in bronchoalveolar lavage fluid (BALF) and the total protein in BALF between the treatment and control groups. SYRCLE's risk of bias tool was used for quality assessment. Results: A total of 17 studies published from 2005 to 2021 were included in our study to calculate the SMD with corresponding confidence interval (CI). As compared with controls, RES significantly decreased the lung injury score (SMD -2.06; 95% CI -2.77, -1.35; p < 0.00001) and W/D ratio (SMD -1.92; 95% CI -2.62, -1.22; p < 0.00001). RES also reduced the number of neutrophils in BALF (SMD -3.03; 95% CI -3.83, -2.24; p < 0.00001) and the total protein in BALF (SMD -5.59; 95% CI -10.10, -1.08; p = 0.02). Furthermore, RES was found to downregulate proinflammatory mediators such as TNF-α (SMD -2.02; 95% CI -3.09, -0.95; p = 0.0002), IL-1ß (SMD -2.51; 95% CI -4.00, -1.02; p = 0.001) and IL-6 (SMD -2.26; 95% CI -3.49, -1.04; p = 0.0003). But RES had little effect on the anti-inflammatory mediators such as IL-10 (SMD 2.80; 95% CI -0.04, 5.63; p = 0.05). Sensitivity analysis and stratified analysis were performed for the outcome indicators with heterogeneity. Conclusion: RES treatment is effective on reducing the severity of ALI. However, more animal studies and human trials are needed for further investigation. Our study may provide a reference for preclinical and clinical studies in the future to some extent.

Efficacy of Resveratrol in Experimental Subarachnoid Hemorrhage Animal Models: A Stratified Meta-Analysis.

Background: Subarachnoid hemorrhage (SAH) is a serious neurosurgical emergency with extremely high morbidity and mortality rates. Resveratrol (RES), a natural polyphenolic phytoalexin, is broadly presented in a wide variety of plants. Previous research had reasonably revealed its neuroprotective effects on experimental SAH animal models to some extent. But the results were more controversial. Therefore, we conducted a meta-analysis to evaluate the evidence on the effectiveness of RES in improving outcomes in SAH animal models. Methods: A systematic literature review was conducted in PubMed, EMBASE, and Web of Science databases to incorporate experimental control studies on the efficacy of RES on SAH models into our research. The standardized mean difference (SMD) was used to compare the brain water content (BWC) and neurological score (NS) between the treatment and control groups. Results: Overall, 16 articles published from 2014 to 2022 met the inclusion criteria. The meta-analysis of BWC showed a significant difference in favor of RES treatment (SMD: -1.026; 95% CI: -1.380, -0.672; p = 0.000) with significant heterogeneity (Q = 84.97; I2 = 60.0%; p = 0.000). Further stratified analysis was performed for methodological differences, especially dosage, time of treatments, and time-point of outcome assessment. The meta-analysis of NS showed a significant difference in favor of RES treatment (SMD: 1.342; 95% CI: 1.089, 1.595; p = 0.000) with low heterogeneity (Q = 25.58; I2 = 17.9%; p = 0.223). Conclusion: Generally, RES treatment showed an improvement in both pathological and behavioral outcomes in SAH animal models. The results of this study may provide a reference for preclinical and clinical studies in the future to some extent, with great significance for human health.

Willis covered stent treatment for blood blister-like aneurysm: A meta-analysis of efficacy and safety.

Background: Blood blister-like aneurysm (BBA) is a rare and special type of intracranial aneurysm with extremely high rates of rupture, morbidity, mortality, and recurrence. Willis Covered Stent (WCS) is a new device that is specifically designed for the treatment of intracranial complex aneurysms. However, the efficacy and safety of WCS treatment for BBA remain controversial. Thus, a high level of evidence is required to prove the efficacy and safety of WCS treatment. Methods: A systematic literature review was performed using a comprehensive literary search in Medline, Embase, and Web of Science databases to identify studies related to WCS treatment for BBA. A meta-analysis was then conducted to incorporate the efficacy and safety outcomes, including intraoperative situation, post-operative situation, and follow-up data. Results: Eight non-comparative studies containing 104 patients with 106 BBAs met the inclusion criteria. In the intraoperative situation, the technical success rate was 99.5% [95% confidence interval (CI), 0.958, 1.000], the complete occlusion rate was 98.2% (95% CI, 0.925, 1.000), and the side branch occlusion rate was 4.1% (95% CI, 0.001, 0.114). Vasospasm and dissection occurred in 9.2% (95% CI, 0.000, 0.261) and 0.1% (95% CI, 0.000, 0.032) of the patients, respectively. In the post-operative situation, the rebleed and mortality rates were 2.2% (95% CI, 0.000, 0.074) and 1.5% (95% CI, 0.000, 0.062), respectively. In the follow-up data, recurrence and parent artery stenosis occurred in 0.3% (95% CI, 0.000, 0.042) and 9.1% (95% CI, 0.032, 0.168) of the patients, respectively. Ultimately, 95.7% (95% CI, 0.889, 0.997) of the patients had a good outcome. Conclusions: Willis Covered Stent could be effectively and safely applied for BBA treatment. The results provide a reference for clinical trials in the future. Well-designed prospective cohort studies must be conducted for verification.