Brain genomics of intracerebral hemorrhage

SLC45A3 Serves as a Potential Therapeutic Biomarker to Attenuate White Matter Injury After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a severe cerebrovascular disease, which impairs patients' white matter even after timely clinical interventions. Indicated by studies in the past decade, ICH-induced white matter injury (WMI) is closely related to neurological deficits; however, its underlying mechanism and pertinent treatment are yet insufficient. We gathered two datasets (GSE24265 and GSE125512), and by taking an intersection among interesting genes identified by weighted gene co-expression networks analysis, we determined target genes after differentially expressing genes in two datasets. Additional single-cell RNA-seq analysis (GSE167593) helped locate the gene in cell types. Furthermore, we established ICH mice models induced by autologous blood or collagenase. Basic medical experiments and diffusion tensor imaging were applied to verify the function of target genes in WMI after ICH. Through intersection and enrichment analysis, gene SLC45A3 was identified as the target one, which plays a key role in the regulation of oligodendrocyte differentiation involving in fatty acid metabolic process, etc. after ICH, and single-cell RNA-seq analysis also shows that it mainly locates in oligodendrocytes. Further experiments verified overexpression of SLC45A3 ameliorated brain injury after ICH. Therefore, SLC45A3 might serve as a candidate therapeutic biomarker for ICH-induced WMI, and overexpression of it may be a potential approach for injury attenuation.

Gene expression changes implicate specific peripheral immune responses to Deep and Lobar Intracerebral Hemorrhages in humans

The peripheral immune system response to Intracerebral Hemorrhage (ICH) may differ with ICH in different brain locations. Thus, we investigated peripheral blood mRNA expression of Deep ICH, Lobar ICH, and vascular risk factor-matched control subjects (n = 59). Deep ICH subjects usually had hypertension. Some Lobar ICH subjects had cerebral amyloid angiopathy (CAA). Genes and gene networks in Deep ICH and Lobar ICH were compared to controls. We found 774 differentially expressed genes (DEGs) and 2 co-expressed gene modules associated with Deep ICH, and 441 DEGs and 5 modules associated with Lobar ICH. Pathway enrichment showed some common immune/inflammatory responses between locations including Autophagy, T Cell Receptor, Inflammasome, and Neuroinflammation Signaling. Th2, Interferon, GP6, and BEX2 Signaling were unique to Deep ICH. Necroptosis Signaling, Protein Ubiquitination, Amyloid Processing, and various RNA Processing terms were unique to Lobar ICH. Finding amyloid processing pathways in blood of Lobar ICH patients suggests peripheral immune cells may participate in processes leading to perivascular/vascular amyloid in CAA vessels and/or are involved in its removal. This study identifies distinct peripheral blood transcriptome architectures in Deep and Lobar ICH, emphasizes the need for considering location in ICH studies/clinical trials, and presents potential location-specific treatment targets.

Secondary injury and inflammation after intracerebral haemorrhage: a systematic review and meta-analysis of molecular markers in patient brain tissue

BACKGROUND

Inflammatory responses to intracerebral haemorrhage (ICH) are potential therapeutic targets. We aimed to quantify molecular markers of inflammation in human brain tissue after ICH compared with controls using meta-analysis.

METHODS

We searched OVID MEDLINE (1946-) and Embase (1974-) in June 2020 for studies that reported any measure of a molecular marker of inflammation in brain tissue from five or more adults after ICH. We assessed risk of bias using a modified Newcastle-Ottawa Scale (mNOS; mNOS score 0-9; 9 indicates low bias), extracted aggregate data, and used random effects meta-analysis to pool associations of molecules where more than two independent case-control studies reported the same outcome and Gene Ontology enrichment analysis to identify over-represented biological processes in pooled sets of differentially expressed molecules (International Prospective Register of Systematic Reviews ID: CRD42018110204).

RESULTS

Of 7501 studies identified, 44 were included: 6 were case series and 38 were case-control studies (median mNOS score 4, IQR 3-5). We extracted data from 21 491 analyses of 20 951 molecules reported by 38 case-control studies. Only one molecule (interleukin-1β protein) was quantified in three case-control studies (127 ICH cases vs 41 ICH-free controls), which found increased abundance of interleukin-1β protein after ICH (corrected standardised mean difference 1.74, 95% CI 0.28 to 3.21, p=0.036, I2=46%). Processes associated with interleukin-1β signalling were enriched in sets of molecules that were more abundant after ICH.

CONCLUSION

Interleukin-1β abundance is increased after ICH, but analyses of other inflammatory molecules after ICH lack replication. Interleukin-1β pathway modulators may optimise inflammatory responses to ICH and merit testing in clinical trials.

Lipoxin A4 Receptor Stimulation Attenuates Neuroinflammation in a Mouse Model of Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is caused by the rupture of blood vessels in the brain. The excessive activation of glial cells and the infiltration of numerous inflammatory cells are observed during bleeding. Thrombin is a key molecule that triggers neuroinflammation in the ICH brain. In this study, we focused on lipoxin A₄ (LXA₄), an arachidonic acid metabolite that has been reported to suppress inflammation and cell migration. LXA₄ and BML-111, an agonist of the LXA₄ receptor/formyl peptide receptor 2 (ALX/FPR2), suppressed microglial activation; LXA₄ strongly inhibited the migration of neutrophil-like cells in vitro. ALX/FPR2 was expressed on neutrophils in the ICH mouse brain and the daily administration of BML-111 attenuated the motor coordination dysfunction and suppressed the production of proinflammatory cytokines in the ICH mouse brain. On the other hand, BML-111 did not show a significant reduction in the number of microglia and neutrophils. These results suggest that systemic administration of ALX/FPR2 agonists may suppress the neuroinflammatory response of microglia and neutrophils without a change in cell numbers. Additionally, their combination with molecules that reduce cell numbers, such as modulators of leukotriene B₄ signaling, may be required in future studies.

Integrated Multiomics Analysis Identifies a Novel Biomarker Associated with Prognosis in Intracerebral Hemorrhage

Existing treatments for intracerebral hemorrhage (ICH) are unable to satisfactorily prevent development of secondary brain injury after ICH and multiple pathological mechanisms are involved in the development of the injury. In this study, we aimed to identify novel genes and proteins and integrated their molecular alternations to reveal key network modules involved in ICH pathology. A total of 30 C57BL/6 male mice were used for this study. The collagenase model of ICH was employed, 3 days after ICH animals were tested neurological. After it, animals were euthanized and perihematomal brain tissues were collected for transcriptome and TMT labeling-based quantitative proteome analyses. Protein-protein interaction (PPI) network, Gene Set Enrichment Analysis (GSEA), and regularized Canonical Correlation Analysis (rCCA) were performed to integrated multiomics data. For validation of hub genes and proteins, qRT-PCR and Western blot were carried out. The candidate biomarkers were further measured by ELISA in the plasma of ICH patients and the controls. A total of 2218 differentially expressed genes (DEGs) and 353 differentially expressed proteins (DEPs) between the ICH model group and control group were identified. GSEA revealed that immune-related gene sets were prominently upregulated and significantly enriched in pathways of inflammasome complex, negative regulation of interleukin-12 production, and pyroptosis during the ICH process. The rCCA network presented two highly connective clusters which were involved in the sphingolipid catabolic process and inflammatory response. Among ten hub genes screened out by integrative analysis, significantly upregulated Itgb2, Serpina3n, and Ctss were validated in the ICH group by qRT-PCR and Western blot. Plasma levels of human SERPINA3 (homologue of murine Serpina3n) were elevated in ICH patients compared with the healthy controls (SERPINA3: 13.3 ng/mL vs. 11.2 ng/mL, p = 0.015). Within the ICH group, higher plasma SERPINA3 levels with a predictive threshold of 14.31 ng/mL (sensitivity = 64.3%; specificity = 80.8%; AUC = 0.742, 95% CI: 0.567-0.916) were highly associated with poor outcome (mRS scores 4-6). Taken together, the results of our study exhibited molecular changes related to ICH-induced brain injury by multidimensional analysis and effectively identified three biomarker candidates in a mouse ICH model, as well as pointed out that Serpina3n/SERPINA3 was a potential biomarker associated with poor functional outcome in ICH patients.

Intracerebral Proinflammatory Cytokine Increase in Surgically Evacuated Intracerebral Hemorrhage: A Microdialysis Study

Background

Treatment options for spontaneous intracerebral hemorrhage (ICH) are limited. A possible inflammatory response in the brain tissue surrounding an ICH may exacerbate the initial injury and could be a target for treatment of subsequent secondary brain injury. The study objective was to compare levels of inflammatory mediators in the interstitial fluid of the perihemorrhagic zone (PHZ) and in seemingly normal cortex (SNX) in the acute phase after surgical evacuation of ICH, with the hypothesis being that a difference could be demonstrated between the PHZ and the SNX.

Methods

In this observational study, ten patients needing surgical evacuation of supratentorial ICH received two cerebral microdialysis catheters: one in the PHZ and one in the SNX that is remote from the ICH. The microdialysate was analyzed for energy metabolites (including lactate pyruvate ratio and glucose) and for inflammatory mediators by using a multiplex immunoassay of 27 cytokines and chemokines at 6–10 h, 20–26 h, and 44–50 h after surgery.

Results

A metabolic crisis, indicated by altered energy metabolic markers, that persisted throughout the observation period was observed in the PHZ when compared with the SNX. Proinflammatory cytokines interleukin (IL) 8, tumor necrosis factor α, IL-2, IL-1β, IL-6 and interferon γ, anti-inflammatory cytokine IL-13, IL-4, and vascular endothelial growth factor A were significantly higher in PHZ compared with SNX and were most prominent at 20–26 h following ICH evacuation.

Conclusions

Higher levels of both proinflammatory and anti-inflammatory cytokines in the perihemorrhagic brain tissue implies a complex role for inflammatory mediators in the secondary injury cascades following ICH surgery, suggesting a need for targeted pharmacological interventions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01389-9.

Identification of Candidate Blood mRNA Biomarkers in Intracerebral Hemorrhage Using Integrated Microarray and Weighted Gene Co-expression Network Analysis

Purpose

Intracerebral hemorrhage (ICH) is a serious public health hazard due to its high morbidity, disability, and mortality. Currently, the exact molecular mechanisms of ICH are unknown. We tried to identify the ICH-related candidate blood messenger RNA (mRNA) biomarkers by microarray analysis and weighted gene co-expression network analysis (WGCNA).

Materials and Methods

We collected the blood samples from patients with ICH (n = 4) and from vascular risk factor (VRF) controls (n = 4) and analyzed the mRNA expression profiles by competitive endogenous RNA (ceRNA) microarray. Differentially expressed genes (DEGs) were identified and then a weighted gene co-expression network was constructed. Modules with clinical significance were distinguished. Then, we downloaded two Gene Expression Omnibus (GEO) datasets (GSE24265 and GSE125512). Candidate mRNAs were identified by taking the intersection of the DEGs in our microarray, the interesting genes in the key module, and the DEGs in GSE24265. Functional analysis involving Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) and construction of a protein–protein interaction (PPI) network were conducted.

Results

A total of 340 DEGs in our microarray were identified between the ICH group and the control group. Among the eight gene modules established by WGCNA, the yellow module containing 191 genes was the most strongly associated with ICH. Four candidate mRNAs (C3AR1, PAWR, ARNTL2, and LDLRAD4) were identified. In the early stage of ICH (within 24 h), C3AR1, PAWR, and ARNTL2 were highly expressed in the perihematomal tissue, but with low expressions in peripheral blood; in the late stage (72 h after the first blood draw), an obvious upward trend of C3AR1 and PAWR in peripheral blood was seen. Functional analysis showed that candidate mRNAs were concerned with multiple pathways, such as the Wnt signaling pathway and calcium signaling pathway. They might affect the process of ICH through neuroinflammation, cell apoptosis, and pyroptosis.

Conclusion

We identified four candidate blood mRNAs (C3AR1, PAWR, ARNTL2, and LDLRAD4) related to ICH. They showed different expression patterns in peripheral blood and perihematomal tissues and changed with time. They might play important roles in ICH through neuroinflammation, cell apoptosis, and pyroptosis and might shed new light to novel biomarkers or therapeutic targets in ICH.

Relationship Between Glycosylated Hemoglobin and Short-Term Mortality of Spontaneous Intracerebral Hemorrhage

Background: The relationship between glycosylated hemoglobin (HbA1c) and prognosis of spontaneous intracerebral hemorrhage (SICH) patients has not been fully elucidated. This study aimed to reveal the relationship between HbA1c levels and short-term mortality after patient admission with SICH. Methods: It was a large-scale, multicenter, cross-sectional study. From August 1, 2015, to July 31, 2019, a total of 41910 SICH patients were included in the study from the Chinese Stroke Center Alliance (CSCA) program. Finally, we comprehensively analyzed the data from 21,116 patients with SICH. HbA1c was categorized into four groups by quartile. Univariate and multivariate logistic regression analyses were used to assess the association between HbA1c levels and short-term mortality in SICH patients. Results: The average age of the 21,116 patients was 62.8 ± 13.2 years; 13,052 (61.8%) of them were male, and 507 (2.4%) of them died. Compared to the higher three quartiles of HbA1c, the lowest quartile (≤5.10%) had higher short-term mortality. In subgroup analysis with or without diabetes mellitus (DM) patients, the mortality of the Q3 group at 5.60-6.10% was significantly lower than that of the Q1 group at ≤5.10%. After adjustment for potential influencing factors, the ROC curve of HbA1c can better predict the short-term mortality of patients with SICH (AUC = 0.6286 P < 0.001). Conclusions: Therefore, we concluded that low or extremely low HbA1c levels (≤5.10%) after stroke were associated with higher short-term mortality in SICH patients, with or without DM.

Temporal metabolomic alteration in rat brains of experimental intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is the top lethal and disabling form of stroke. The pathophysiology of ICH is not fully understood yet. Metabolites are indicators and regulators of cellular processes. However, the overall brain metabolic pattern and the temporal alterations after ICH remain unknown.

METHODS

A total of 40 male rats were randomly assigned to sham group and ICH group. ICH was induced by collagenase Ⅶ. Body weight was assessed. Neurological deficits were evaluated by modified neurological severity score. Then, the perihematomal brain tissues were collected for metabolites detection using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS). The metabolic profiles were displayed by principal component analysis (PCA), partial least-squares-discriminant analysis (PLS-DA) and cluster analysis. The significant differential metabolites were screened by fold change > 2.0, the false discovery rate (FDR) < 0.05 and Variable Importance of Projection (VIP) > 1. Next, the relevant metabolic pathways were discerned by MetaboAnalyst website. A metabolite-protein interaction network was subsequentially constructed to further annotate the function of differential metabolites.

RESULTS

Rats suffered from compromised body weight increasement and impaired neurological function. The metabolomics profiles of brain tissues in the post-ICH rats were markedly different from those in the sham group on days 3 and 14. Thirty-four metabolites (bilirubin, uric acid, 6-Methylnicotinamide et al.) were abnormally upregulated in the acute stage, while 27 metabolites were disturbed in the recovery stage, including bilirubin, uric acid, and histamine et al. Seven and three metabolic pathways altered in the acute and recovery stage, respectively. Metabolite-protein interaction analysis revealed that the disturbed metabolites may participate in ICH pathophysiology by altering amino acid metabolism, peroxisome proliferators-activated receptor signaling pathway, fatty acid metabolism and urea cycle in the acute stage, while influencing amino acid metabolism, urea cycle and peroxisome in the recovery stage.

CONCLUSIONS

Our study mapped the pathological metabolomics profiles of the post-ICH rat brains in the acute and recovery phases. This work will assist in discovering novel therapeutic targets and treatments for ICH.

Effect of Pioglitazone on Perihematomal Edema in Intracerebral Hemorrhage Mouse Model by Regulating NLRP3 Expression and Energy Metabolism

Objective

Cerebral edema is the predominant mechanism of secondary inflammation after intracerebral hemorrhage (ICH). Pioglitazone, peroxisome proliferator-activated receptor gamma agonist has been shown to play a role in regulation of central nervous system inflammation. Here, we examined the pharmacological effects of pioglitazone in an ICH mouse model and investigated its regulation on NLRP3 inflammasome and glucose metabolism.

Methods

The ICH model was established in C57 BL/6 mice by the stereotactical inoculation of blood (30 µL) into the right frontal lobe. The treatment group was administered i.p. pioglitazone (20 mg/kg) for 1, 3, and 6 days. The control group was administered i.p. phosphate-buffered saline for 1, 3, and 6 days. We investigated brain water contents, NLRP3 expression, and changes in the metabolites in the ICH model using liquid chromatography-tandem mass spectrometry.

Results

On day 3, brain edema in the mice treated with pioglitazone was decreased more than that in the control group. Expression levels of NLRP3 in the ICH model treated with pioglitazone were decreased more than those of the control mice on days 3 and 7. The pioglitazone group showed higher levels of glycolytic metabolites than those in the ICH mice. Lactate production was increased in the ICH mice treated with pioglitazone.

Conclusion

Our results demonstrated less brain swelling following ICH in mice treated with pioglitazone. Pioglitazone decreased NLRP3-related brain edema and increased anaerobic glycolysis, resulting in the production of lactate in the ICH mice model. NLRP3 might be a therapeutic target for ICH recovery.

Fgr contributes to hemorrhage-induced thalamic pain by activating NF-κB/ERK1/2 pathways

Thalamic pain, a type of central poststroke pain, frequently occurs following ischemia/hemorrhage in the thalamus. Current treatment of this disorder is often ineffective, at least in part due to largely unknown mechanisms that underlie thalamic pain genesis. Here, we report that hemorrhage caused by microinjection of type IV collagenase or autologous whole blood into unilateral ventral posterior lateral nucleus and ventral posterior medial nucleus of the thalamus increased the expression of Fgr, a member of the Src family nonreceptor tyrosine kinases, at both mRNA and protein levels in thalamic microglia. Pharmacological inhibition or genetic knockdown of thalamic Fgr attenuated the hemorrhage-induced thalamic injury on the ipsilateral side and the development and maintenance of mechanical, heat, and cold pain hypersensitivities on the contralateral side. Mechanistically, the increased Fgr participated in hemorrhage-induced microglial activation and subsequent production of TNF-α likely through activation of both NF-κB and ERK1/2 pathways in thalamic microglia. Our findings suggest that Fgr is a key player in thalamic pain and a potential target for the therapeutic management of this disorder.

Microglia-released leukotriene B4 promotes neutrophil infiltration and microglial activation following intracerebral hemorrhage

Intracerebral hemorrhage (ICH) from blood vessel rupture results in parenchymal hematoma formation and neuroinflammation, ultimately leading to neurodegeneration. Several lines of evidence suggest that the severity of ICH-induced neural damage is exacerbated by infiltration of T-cells, monocytes, and especially neutrophils into the hematoma. Neutrophil migration is regulated by chemokines, formyl peptides, and leukotriene B₄ (LTB₄), a metabolite of arachidonic acid. In this study, we demonstrate that LTB₄ is a key signaling factor promoting microglial activity and leukocyte infiltration into hematoma and thus a potentially critical determinant of ICH pathogenesis and clinical outcome. Lipidomic analysis revealed markedly increased LTB₄ concentration in the hematoma-containing brain tissues 6-24 h after experimental ICH in mice. Expression of 5-lipoxygenase, a rate-limiting enzyme for LTB₄ production, was upregulated in activated microglia and neutrophils within the hematoma following ICH. Treatment of cultured BV-2 microglia with thrombin, which is abundant in hematoma, promoted activation, proinflammatory cytokine expression, and LTB₄ secretion. Further, conditioned medium from thrombin-stimulated BV-2 cells potentiated the transwell migration of neutrophil-like cells, a response blocked by a LTB₄ receptor antagonist. These results suggest that arachidonic acid conversion to LTB₄ following ICH contributes to neuroinflammation and ensuing neural tissue damage by inducing microglial activation and neutrophil recruitment.

Matrix Metalloproteinases in Acute Intracerebral Hemorrhage

Spontaneous intracerebral hemorrhage (ICH) accounts for 10-30% of all strokes and affects more than one million people every year worldwide, and it is the stroke subtype associated with the highest rates of mortality and residual disability. So far, clinical trials have mainly targeted primary cerebral injury and have substantially failed to improve clinical outcomes. The understanding of the pathophysiology of early and delayed injury after ICH is, hence, of paramount importance to identify potential targets of intervention and develop effective therapeutic strategies. Matrix metalloproteinases (MMPs) represent a ubiquitous superfamily of structurally related zinc-dependent endopeptidases able to degrade any component of the extracellular matrix. They are upregulated after ICH, in which different cell types, including leukocytes, activated microglia, neurons, and endothelial cells, are involved in their synthesis and secretion. The aim of this review is to summarize the available experimental and clinical evidence about the role of MMPs in brain injury following spontaneous ICH and provide critical insights into the underlying mechanisms.

Association of pre- and post-stroke glycemic status with clinical outcome in spontaneous intracerebral hemorrhage

In this study, we aimed to disclose the association of pre- and post-stroke glycemic status with clinical outcome in patients with spontaneous intracerebral hemorrhage (sICH). It was a multicenter, prospective, observational cohort study, conducted in 13 hospitals in Beijing from January 2014 to September 2016. The association of admission random blood glucose (RBG), fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) with clinical outcome at 90 days after sICH onset were analyzed comprehensively. Poor outcome was defined as death or modified Rankin Scale (mRS) score >2. The results showed that elevated RBG and FBG were associated with larger hematoma volume, lower GCS, higher NIHSS (P < 0.001), and poor outcome, but HbA1c was not (P > 0.05). In stratified analysis, the association of poor outcome with elevated FBG or RBG retained statistical significance just in patients without diabetes. Kaplan-Meier curve and Cox regression showed that patients with elevated FBG or RBG had significantly higher risk of death within 90 days (P < 0.05). So we conclude that poststroke hyperglycemia was associated with larger hematoma volume, severe neurological damage and poor clinical outcome, but HbA1c was not relevant to hematoma volume or clinical outcome in patients with sICH.

PIAS genes as disease markers in bipolar disorder

The protein inhibitors of activated STAT (PIAS) are involved in regulation of many transcription factors and signaling pathways that contribute to the pathogenesis of bipolar disease (BD). In the current study, we evaluated the expression of four PIAS genes (PIAS1-4) in peripheral blood of BD patients and healthy subjects to explore their contribution in the pathogenesis of BD and their suitability as peripheral biomarkers for this disorder. All PIAS genes were significantly upregulated in total BD patients compared with total controls. The sex-based analysis confirmed upregulation of PIAS1-4 genes in male BD patients compared with male controls (P < 0.001). However, PIAS1 was significantly downregulated in female patients compared with female controls (P = 0.02). Expression levels of other PIAS genes were not significantly different between female patients and female controls. There were no significant correlations between expression levels of PIAS genes and any of the clinical data of study participants after adjustment of the effects of the sex. On the basis of the area under the curve (AUC) values in receiver operating characteristic curves, PIAS4 had the best performance in the differentiation of disease status between study participants (AUC = 0.81). PIAS3 and PIAS4 genes had the best sensitivity and specificity values, respectively. Combination of expression levels of four genes resulted in the improvement of diagnostic power (AUC = 0.82). The current data implies the role of PIAS genes in the pathogenesis of BD and denotes their suitability as peripheral markers for this disorder.

Biomarker and Drug Target Discovery Using Quantitative Proteomics Post-Intracerebral Hemorrhage Stroke in the Rat Brain

The pathological mechanisms of acute intracerebral hemorrhage (ICH) remain unknown and unverified. In the present study, we used quantitative proteomics to elucidate the pathological mechanisms and to identify novel biomarker and therapeutic target candidates via tissue proteome in a rat model of acute ICH. Rats were experimentally induced with ICH (n = 6) or Sham (n = 6), and their brain tissue was obtained by 24 h. The TMT-LC–MS/MS-based proteomics approach was used to quantify the differential proteomes across brain tissue, and the results were further analyzed by ingenuity pathway analysis to explore canonical pathways and the relationship involved in the uploaded data. Upon quantification, we found that 96 secreted proteins that were identified in the ICH 24-h group were significantly different those in the control group (P < 0.05); among these proteins, 57 increased and 39 decreased in abundance. Bioinformatic analyses of differentially expressed proteins demonstrated that the protein localization and ERK1 and ERK2 cascade were the top two biological processes with the highest concentrations of differentially proteins. The top protein-protein action network with high confidence levels of protein was the albumin and ERK signaling pathways. Albumin, ERK, and p-ERK were assessed in brain tissue by western blot analysis, and higher expression levels of albumin and p-ERK were observed in the ICH group. Our proteomic results highlight important change in the biological processes of ERK1 and ERK2 cascade, which are possible targets for future interventions of ICH. To our knowledge, this study provides in-depth analysis of ICH in brain tissue, and we propose 96 new biomarker candidates for ICH, including albumin and ERK.

CCL2 and CXCL10 are associated with poor outcome after intracerebral hemorrhage

OBJECTIVE

Intracerebral hemorrhage carries a high mortality and survivors are frequently left with significant disability. Immunological mechanisms may play an important role in hemorrhage-induced brain injury, however, research linking these mechanisms with clinical outcome remains limited. We aim to identify serum inflammatory mediators that are associated with outcome after intracerebral hemorrhage in order to translate data from experimental models to a patient cohort and identify potential targets worthy of reverse translation.

METHODS

A prospective cohort study at two comprehensive stroke centers enrolled patients with spontaneous intracerebral hemorrhage. Peripheral blood was collected at 6, 24, and 72 h from onset. Functional outcome was assessed at 90 days using the modified Rankin Scale (mRS). Serum inflammatory mediators were measured using multiplex ELISA. Multivariable modeling identified serum biomarkers independently associated with functional outcome at 90 days.

RESULTS

115 patients completed the study. At 6 h after onset, patients with elevated CCL2 had worse mRS score at day 90 (OR 4.07, 95% CI 1.27-13.10, P = 0.02) after adjusting for age, gender, ICH volume, IVH, infratentorial location and NIHSS score. At 24 and 72 h after onset, elevation in CXCL10 was independently associated with worse 90 days mRS score (24 h: OR 8.08, 95% CI 2.69-24.30, P < 0.001; 72 h: OR 3.89, 95% CI 1.12-13.49, P = 0.03).

INTERPRETATION

Acute and subacute elevations in specific immune factors are associated with poor outcome, highlighting potential pathways that may contribute to ongoing brain injury in patients with intracerebral hemorrhage.

Modulators of microglial activation and polarization after intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is the most lethal subtype of stroke but currently lacks effective treatment. Microglia are among the first non-neuronal cells on the scene during the innate immune response to ICH. Microglia respond to acute brain injury by becoming activated and developing classic M1-like (proinflammatory) or alternative M2-like (anti-inflammatory) phenotypes. This polarization implies as yet unrecognized actions of microglia in ICH pathology and recovery, perhaps involving microglial production of proinflammatory or anti-inflammatory cytokines and chemokines. Furthermore, alternatively activated M2-like microglia might promote phagocytosis of red blood cells and tissue debris, a major contribution to haematoma clearance. Interactions between microglia and other cells modulate microglial activation and function, and are also important in ICH pathology. This Review summarizes key studies on modulators of microglial activation and polarization after ICH, including M1-like and M2-like microglial phenotype markers, transcription factors and key signalling pathways. Microglial phagocytosis, haematoma resolution, and the potential crosstalk between microglia and T lymphocytes, neurons, astrocytes, and oligodendrocytes in the ICH brain are described. Finally, the clinical and translational implications of microglial polarization in ICH are presented, including the evidence that therapeutic approaches aimed at modulating microglial function might mitigate ICH injury and improve brain repair.

Identification of novel biomarker and therapeutic target candidates for acute intracerebral hemorrhage by quantitative plasma proteomics

Background

The systematic mechanisms of acute intracerebral hemorrhage are still unknown and unverified, although many recent researches have indicated the secondary insults. This study was aimed to disclose the pathological mechanism and identify novel biomarker and therapeutic target candidates by plasma proteome.

Methods

Patients with AICH (n = 8) who demographically matched healthy controls (n = 4) were prospectively enrolled, and their plasma samples were obtained. The TMT-LC–MS/MS-based proteomics approach was used to quantify the differential proteome across plasma samples, and the results were analyzed by Ingenuity Pathway Analysis to explore canonical pathways and the relationship involved in the uploaded data.

Results

Compared with healthy controls, there were 31 differentially expressed proteins in the ICH group (P < 0.05), of which 21 proteins increased while 10 proteins decreased in abundance. These proteins are involved in 21 canonical pathways. One network with high confidence level was selected by the function network analysis, in which 23 proteins, P38MAPK and NFκB signaling pathways participated. Upstream regulator analysis found two regulators, IL6 and TNF, with an activation z-score. Seven biomarker candidates: APCS, FGB, LBP, MGMT, IGFBP2, LYZ, and APOA4 were found. Six candidate proteins were selected to assess the validity of the results by subsequent Western blotting analysis.

Conclusion

Our analysis provided several intriguing pathways involved in ICH, like LXR/RXR activation, acute phase response signaling, and production of NO and ROS in macrophages pathways. The three upstream regulators: IL-6, TNF, LPS, and seven biomarker candidates: APCS, APOA4, FGB, IGFBP2, LBP, LYZ, and MGMT were uncovered. LPS, APOA4, IGFBP2, LBP, LYZ, and MGMT are novel potential biomarkers in ICH development. The identified proteins and pathways provide new perspectives to the potential pathological mechanism and therapeutic targets underlying ICH.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-017-9149-x) contains supplementary material, which is available to authorized users.

A TSPO ligand attenuates brain injury after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating disease without effective treatment. After ICH, the immediate infiltration of leukocytes and activation of microglia are accompanied by a rapid up-regulation of the 18-kDa translocator protein (TSPO). TSPO ligands have shown anti-inflammatory and neuroprotective properties in models of CNS injury. In this study, we determined the impact of a TSPO ligand, etifoxine, on brain injury and inflammation in 2 mouse models of ICH. TSPO was up-regulated in Iba1⁺ cells from brains of patients with ICH and in CD11b⁺CD45^int cells from mice subjected to collagenase-induced ICH. Etifoxine significantly reduced neurodeficits and perihematomal brain edema after ICH induction by injection of either autologous blood or collagenase. In collagenase-induced ICH mice, the protection of etifoxine was associated with reduced leukocyte infiltration into the brain and microglial production of IL-6 and TNF-α. Etifoxine improved blood–brain barrier integrity and diminished cell death. Notably, the protective effect of etifoxine was abolished in mice depleted of microglia by using a colony-stimulating factor 1 receptor inhibitor. These results indicate that the TSPO ligand etifoxine attenuates brain injury and inflammation after ICH. TSPO may be a viable therapeutic target that requires further investigations in ICH.—Li, M., Ren, H., Sheth, K. N., Shi, F.-D., Liu, Q. A TSPO ligand attenuates brain injury after intracerebral hemorrhage.

NLRP3 is Required for Complement-Mediated Caspase-1 and IL-1beta Activation in ICH

Complement-mediated inflammation plays a vital role in intracerebral hemorrhage (ICH), implicating pro-inflammatory factor interleukin-1beta (IL-1β) secretion. Brain samples and contralateral hemiencephalon were all collected and detected by Western blot. NLRP3 expression was located by dual immunofluorescence staining at 1, 3, and 5 days post-ICH. Brain water content was examined post-ICH. The neural deficit scores were evaluated by observers blindly. ILs were detected by ELISA. SiRNAs targeting NLRP3 (siNLRP3), siASC, and siControl were injected to inhibit NLRP3 function. To test the complement activation via Nod-like receptor (NLR) family pyrin domain-containing 3 (NLRP3), normal rabbit complement (NRC) was injected with lipopolysaccharide (LPS) to facilitate the complement function. As a result, complement 3a (C3a) and complement 5a (C5a) were upregulated during the ICH-induced neuroinflammation, and ablation of C3 attenuates ICH-induced IL-1β release. Though the LPS rescues the neuroinflammation in the ICH model, C3 deficiency attenuates the LPS-induced inflammatory effect. The NLRP3 inflammasome was activated after ICH and was located in the microglial cell of the mouse brain, which exhibits a time-dependent manner. However, the number of NLRP3/Iba-1 dual-labeled cells in the C3^-/- group is less than that in the WT group in each time course, respectively. IL-1β and IL-18 released in perihematoma tissue, caspase-1-p20, brain water content, and behavioral outcomes were attenuated in the siNLRP3 and siASC groups than in the siControl and ICH groups. We also found that 5% of complement supplement enhances ICH-induced IL-1β release, while NLRP3 and ASC inhibition attenuates it. In conclusion, complement-induced ICH neuroinflammation depended on NLRP3 activation, which facilities LPS- and ICH-induced neuroinflammation, and NLRP3 is required for ICH-induced inflammation.

Neuro-regeneration therapy using human Muse cells is highly effective in a mouse intracerebral hemorrhage model

A novel type of non-tumorigenic pluripotent stem cell, the Muse cell (multi-lineage, differentiating stress enduring cell), resides in the connective tissue and in cultured mesenchymal stem cells (MSCs) and is reported to differentiate into multiple cell types according to the microenvironment to repair tissue damage. We examined the efficiency of Muse cells in a mouse intracerebral hemorrhage (ICH) model. Seventy μl of cardiac blood was stereotactically injected into the left putamen of immunodeficient mice. Five days later, 2 × 10⁵ of human bone marrow MSC-derived Muse cells (n = 6) or cells other than Muse cells in MSCs (non-Muse, n = 6) or the same volume of PBS (n = 11) was injected into the ICH cavity. Water maze and motor function tests were implemented for 68 days, and immunohistochemistry for NeuN, MAP2 and GFAP was done. The Muse group showed impressive recovery: Recovery was seen in the water maze after day 19, and motor functions after 5 days was compared with the other two groups, with a significant statistical difference (p < 0.05). The survival rate of the engrafted cells in the Muse group was significantly higher than in the non-Muse group (p < 0.05) at day 69, and those cells showed positivity for NeuN (~57%) and MAP-2 (~41.6%). Muse cells could remain in the ICH brain, differentiate into neural-lineage cells and restore functions without inducing them into neuronal cells by gene introduction and cytokine treatment prior to transplantation. A simple collection of Muse cells and their supply to the brain in naïve state facilitates regenerative therapy in ICH.

After Intracerebral Hemorrhage, Oligodendrocyte Precursors Proliferate and Differentiate Inside White-Matter Tracts in the Rat Striatum

Damage to myelinated axons contributes to neurological deficits after acute CNS injury, including ischemic and hemorrhagic stroke. Potential treatments to promote re-myelination will require fully differentiated oligodendrocytes, but almost nothing is known about their fate following intracerebral hemorrhage (ICH). Using a rat model of ICH in the striatum, we quantified survival, proliferation, and differentiation of oligodendrocyte precursor cells (OPCs) (at 1, 3, 7, 14, and 28 days) in the peri-hematoma region, surrounding striatum, and contralateral striatum. In the peri-hematoma, the density of Olig2⁺ cells increased dramatically over the first 7 days, and this coincided with disorganization and fragmentation of myelinated axon bundles. Very little proliferation (Ki67⁺) of Olig2⁺ cells was seen in the anterior subventricular zone from 1 to 28 days. However, by 3 days, many were proliferating in the peri-hematoma region, suggesting that local proliferation expands their population. By 14 days, the density of Olig2⁺ cells declined in the peri-hematoma region, and, by 28 days, it reached the low level seen in the contralateral striatum. At these later times, many surviving axons were aligned into white-matter bundles, which appeared less swollen or fragmented. Oligodendrocyte cell maturation was prevalent over the 28-day period. Densities of immature OPCs (NG2⁺Olig2⁺) and mature (CC-1⁺Olig2⁺) oligodendrocytes in the peri-hematoma increased dramatically over the first week. Regardless of the maturation state, they increased preferentially inside the white-matter bundles. These results provide evidence that endogenous oligodendrocyte precursors proliferate and differentiate in the peri-hematoma region and have the potential to re-myelinate axon tracts after hemorrhagic stroke.

Effects of intracerebral hemorrhage on 5-hydroxymethylcytosine modification in mouse brains

The past decade has resulted in an increase in the knowledge of molecular mechanisms underlying brain injury induced by intracerebral hemorrhage (ICH). Recent advances have provided a link between epigenetic modification and the regulation of gene expression. 5-hydroxymethylcytosine (5hmC) converted from 5-methylcytosine by the ten-eleven translocation (TET) family of proteins has emerged as a new epigenetic modification. While the dynamics of 5hmC during cerebral ischemia have recently been reported, whether 5hmC is involved in ICH remains unexplored. In this study, we investigated the effects of ICH on DNA hydroxymethylation. We showed that the global level of 5hmC rapidly decreased as early as 24 hours after ICH and persisted until 72 hours. Furthermore, the level of 5hmC in the CpG-rich regions of Akt2, Pdpk1 and Vegf genes was significantly decreased with a minimum level observed at 48 hours or 72 hours. Decreased 5hmC was observed in parallel with an increase in 5-methylcytosine over this time course, and mRNA levels of Akt2, Pdpk1 and Vegf were downregulated upon ICH injury. Finally, Tet1, Tet2 and Tet3 mRNA levels were dramatically decreased in the ICH brain. Our study for the first time established the correlation between DNA hydroxymethylation and ICH injury. Further investigations should examine whether 5hmC modification could be a therapeutic target for the treatment of ICH injury.

Anti-inflammatory effects of fimasartan via Akt, ERK, and NFκB pathways on astrocytes stimulated by hemolysate

OBJECTIVE

The aim of this study was to investigate whether fimasartan, a novel angiotensin II receptor blocker, modulates hemolysate-induced inflammation in astrocytes.

METHODS

We stimulated astrocytes with hemolysate to induce hemorrhagic inflammation in vitro. Astrocytes were pretreated with fimasartan and then incubated with hemolysate at different durations. Anti-inflammatory cell signaling molecules including Akt, extracellular signal regulated kinase (ERK), NFκB and cyclooxygenase-2 (COX-2) were assessed by western blotting. Pro-inflammatory mediators were evaluated by real-time RT-PCR and ELISA.

RESULTS

The stimulation by hemolysate generated a robust activation of inflammatory signaling pathways in astrocytes. Hemolysate increased the phosphorylation of Akt at 1 h, and ERK1/2 at 20 min compared with the control group and promoted the degradation of IκBα. Pretreated fimasartan significantly decreased hemolysate-induced phosphorylation of Akt and ERK1/2. In addition, fimasartan also suppressed NFκB-related inflammatory pathways induced by hemolysate, including reduction of the gene expression of NFκB, and decreased nuclear translocation of NFκB and degradation of IκB. This reduction of inflammatory upstream pathways decreased the expression of inflammatory end-products: COX-2 and interleukin-1 (IL-1β). Furthermore, the expression of COX-2 was attenuated by both Akt inhibitor (LY294002) and ERK inhibitor (U0126), and IκBα degradation was suppressed by LY294002.

CONCLUSIONS

These results demonstrate that pretreatment with fimasartan to astrocytes suppresses the inflammatory responses induced by hemolysate. Akt, ERK and NFκB were associated with hemolysate-induced COX-2 and IL-1β expression. Based on these mechanisms, fimasartan could be a candidate anti-inflammatory regulator for the treatment of intracerebral hemorrhage.

P2X7R blockade prevents NLRP3 inflammasome activation and brain injury in a rat model of intracerebral hemorrhage: involvement of peroxynitrite

BACKGROUND

The NLR family, pyrin domain-containing 3 (NLRP3) inflammasome plays a key role in intracerebral hemorrhage (ICH)-induced inflammatory injury, and the purinergic 2X7 receptor (P2X7R) is upstream of NLRP3 activation. This study aimed to investigate how P2X7R functions in ICH-induced inflammatory injury and how the receptor interacts with the NLRP3 inflammasome.

METHODS

Rats were treated with P2X7R small interfering RNA (siRNA) 24 h before undergoing collagenase-induced ICH. A selective P2X7R inhibitor (blue brilliant G, BBG) or a peroxynitrite (ONOO(-)) decomposition catalyst (5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron(III) [FeTPPS]) was injected 30 min after ICH. Brain water content, hemorrhagic lesion volume, and neurological deficits were evaluated, and western blot, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were carried out.

RESULTS

Striatal P2X7R and NLRP3 inflammasomes were activated after ICH. Gene silencing of P2X7R suppressed NLRP3 inflammasome activation and interleukin (IL)-1β/IL-18 release and significantly ameliorated brain edema and neurological deficits. Additionally, enhanced NADPH oxidase 2 (NOX2, gp91(phox)) and inducible nitric oxide synthase (iNOS), as well as their cytotoxic product (ONOO(-)) were markedly attenuated by BBG treatment following ICH. This was accompanied by downregulations of the inflammasome components, IL-1β/IL-18 and myeloperoxidase (MPO, a neutrophil marker). Most importantly, inflammasome activation and IL-1β/IL-18 release were significantly inhibited by ONOO(-) decomposition with FeTPPS.

CONCLUSIONS

Our findings implicate that P2X7R exacerbated inflammatory progression and brain damage in ICH rats possibly via NLRP3 inflammasome-dependent IL-1β/IL-18 release and neutrophil infiltration. ONOO(-), a potential downstream signaling molecule of P2X7R, may play a critical role in triggering NLRP3 inflammasome activation.

[Chronic intracerebral hemorrhage in the basal ganglia: Report of two cases and prevalence]

Two patients presented with chronic intracerebral hemorrhage (CIH) in the basal ganglia. A 48-year-old man (Case 1) was admitted to our hospital because of hypertensive right putaminal hemorrhage. On day 14, his hematoma surrounding the edema had grown without re-bleeding as seen on head CT, which was then removed endoscopically on day 28. Biopsied specimen of the hematoma capsule showed granulomatous tissue with vascularity. A 54-year-old man (Case 2) was admitted to our hospital because of bilateral intracerebral hemorrhage in the basal ganglia of the right putamen and left thalamus. On head CT, both hematomas were found to be enlarged without change in his symptoms on the 11th day after onset. His symptoms and signs subsided with medical treatment for 4 weeks. Cerebral angiography showed no abnormality of cerebral vessels. The patient had intracerebral hemorrhage in the basal ganglia or cerebral lobes 5 times in the past 10 years. Although no arterial or venous abnormality was detected by cerebral angiography and MRI/MRA, the abnormality of vessels including capillaries was strongly suggested. CIH should be considered a possibility when the symptom or hematoma does not improve even 2 weeks after the onset. The prevalence of CIH in our hospital was 0.08% of total intracerebral hemorrhages and 0.15% of hemorrhages in the basal ganglia.

Prestroke glycemic status is associated with the functional outcome in spontaneous intracerebral hemorrhage

Admission hyperglycemia is thought to be related to poor neurological function and high mortality in patients with spontaneous intracerebral hemorrhage (sICH). However, it is not known whether prestroke glycemic status affects functional outcome of sICH. The study was aimed to disclose the association between prestroke glycemic status and outcome in patients with sICH. The study included 288 patients with sICH. Prestroke glycemic status was represented by hemoglobin A1c (HbA1c) values measured the next day after admission. Correlations between HbA1c and age, hematoma volume, NIHSS, and mRS were analyzed using Spearman's correlation analysis. Patients were categorized into two groups according to hematoma volume (≤25 mL or >25 mL), mRS values (≤2 or >2), or hematoma location (lobar hematoma or deep hematoma). Logistic regression analyses were used to determine the relative independent risk factors for hematoma volume, hematoma location, and mRS values. In patients with sICH, HbA1c was significantly correlated with hematoma volume, NIHSS, and mRS. High HbA1c levels were independently associated with large hematoma volume, deep ICH, and poor outcome. When patients were stratified by history of diabetes, the predictive effect of HbA1c on outcomes was only observed in patients with diabetes. Admission glucose was also related to hematoma volume, but failed to predict outcome. Although both admission glucose and HbA1c independently predicted hematoma volume in patients with sICH, HbA1c alone could serve as a better predictor of poor outcome in diabetic patients after sICH.

Vascular disruption and blood-brain barrier dysfunction in intracerebral hemorrhage

This article reviews current knowledge of the mechanisms underlying the initial hemorrhage and secondary blood-brain barrier (BBB) dysfunction in primary spontaneous intracerebral hemorrhage (ICH) in adults. Multiple etiologies are associated with ICH, for example, hypertension, Alzheimer's disease, vascular malformations and coagulopathies (genetic or drug-induced). After the initial bleed, there can be continued bleeding over the first 24 hours, so-called hematoma expansion, which is associated with adverse outcomes. A number of clinical trials are focused on trying to limit such expansion. Significant progress has been made on the causes of BBB dysfunction after ICH at the molecular and cell signaling level. Blood components (e.g. thrombin, hemoglobin, iron) and the inflammatory response to those components play a large role in ICH-induced BBB dysfunction. There are current clinical trials of minimally invasive hematoma removal and iron chelation which may limit such dysfunction. Understanding the mechanisms underlying the initial hemorrhage and secondary BBB dysfunction in ICH is vital for developing methods to prevent and treat this devastating form of stroke.

Inhibition of Let7c microRNA is neuroprotective in a rat intracerebral hemorrhage model

Intracerebral hemorrhage (ICH) is a devastating neurological disease with a grave prognosis. We evaluated microRNA (miRNA) expression after ICH and evaluated Let7c as a therapeutic target. We harvested hemorrhagic brain 24 hours after collagenase induced ICH in the rat. Microarray analysis was performed to compare the miRNAs expression pattern between hemorrhagic hemisphere and contralateral hemisphere. An in vitro thrombin toxicity model and blood injection ICH model were also used to evaluate miRNA expression. We selected miRNA for the therapeutic target study after reviewing target gene databases and their expression. The antagonistic sequence of the selected miRNA (antagomir) was used to evaluate its therapeutic potential in the in vitro thrombin toxicity and in vivo ICH models. Among 1,088 miRNAs analyzed, let7c was induced in the thrombin and ICH models. Let7c antagomir treatment increased cell survival in the in vitro thrombin injury model and improved neurological function at 4 weeks after ICH. Let7c antagomir decreased perihematoma edema, apoptotic cell death and inflammation around hematoma. Let7c antagomir also induced insulin like growth factor receptor 1 (IGF1R) protein and phosphorylated serine threonine kinase after ICH. This study shows a distinct miRNA expression pattern after ICH. The let7c antagomir reduced cell death and edema and enhanced neurological recovery at least in part by activating the IGF1R pro-survival pathway. This suggests blocking let7c might be a potential therapeutic target in ICH.

Administration of S-methyl-L-thiocitrulline protects against brain injuries after intracerebral hemorrhage

Although intracerebral hemorrhage (ICH) increases the level of glutamate in the perihematomal area and cerebral spinal fluid (CSF) in the ICH acute phase, it is unclear whether elevated glutamate activates neuronal nitric oxide synthase (nNOS) in the ICH brain and whether nNOS is an important target for ICH treatment. Here, we assessed the role of the nNOS inhibitor S-methyl-l-thiocitrulline (SMTC) in the activity of NADPH-d and ICH-induced brain injuries. An autologous blood intracerebral infusion model in male rats was used. All of the rats were sacrificed 24h after ICH. ICH increased NADPH-d activity in the striatum. Administering SMTC 3h after ICH decreased the activity of NADH-d (p<0.05 vs. the ICH group). The activation of gelatinolytic enzymes in the perihematomal region of the striatum was reduced by SMTC treatment (p<0.01, vs. the ICH group). The loss of laminin- and occludin-stained vessels was significant in perihematomal regions after 24h of ICH and was significantly attenuated by the administration of SMTC (p<0.01 for laminin, p<0.05 for occluding, compared with the ICH group). Neuronal death and neurological deficits after ICH were also decreased in SMTC treatment rats (p<0.01, vs. the ICH group). The results suggest that the administration of the nNOS inhibitor SMTC after ICH protects against ICH-induced brain injuries and improves neurological function.

Suppression of CXCL2 upregulation underlies the therapeutic effect of the retinoid Am80 on intracerebral hemorrhage in mice

We previously demonstrated that a synthetic retinoic acid receptor agonist, Am80, attenuated intracerebral hemorrhage (ICH)-induced neuropathological changes and neurological dysfunction. Because inflammatory events are among the prominent features of ICH pathology that are affected by Am80, this study investigated the potential involvement of proinflammatory cytokines/chemokines in the effect of Am80 on ICH. ICH induced by collagenase injection into mouse striatum caused prominent upregulation of mRNAs for interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, CXCL1, CXCL2, and CCL3. We found that dexamethasone (DEX) and Am80 differently modulated the increase in expression of these cytokines/chemokines; TNF-α expression was attenuated only by DEX, whereas CXCL2 expression was attenuated only by Am80. Expression of IL-1β and IL-6 was inhibited both by DEX and Am80. Neurological assessments revealed that Am80, but not DEX, significantly alleviated motor dysfunction of mice after ICH. From these results, we suspected that CXCL2 might be critically involved in determining the extent of motor dysfunction. Indeed, magnetic resonance imaging-based classification of ICH in individual mice revealed that invasion of hematoma into the internal capsule, which has been shown to cause severe neurological disabilities, was associated with higher levels of CXCL2 expression than ICH without internal capsule invasion. Moreover, a CXCR1/2 antagonist reparixin ameliorated neurological deficits after ICH. Overall, suppression of CXCL2 expression may contribute to the beneficial effect of Am80 as a therapeutic agent for ICH, and interruption of CXCL2 signaling may provide a promising target for ICH therapy.

Necrostatin-1 reduces neurovascular injury after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is the most common form of hemorrhagic stroke, accounting for 15% of all strokes. ICH has the highest acute mortality and the worst long-term prognosis of all stroke subtypes. Unfortunately, the dearth of clinically effective treatment options makes ICH the least treatable form of stroke, emphasizing the need for novel therapeutic targets. Recent work by our laboratory identified a novel role for the necroptosis inhibitor, necrostatin-1, in limiting neurovascular injury in tissue culture models of hemorrhagic injury. In the present study, we tested the hypothesis that necrostatin-1 reduces neurovascular injury after collagenase-induced ICH in mice. Necrostatin-1 significantly reduced hematoma volume by 54% at 72 h after-ICH, as compared to either sham-injured mice or mice administered an inactive, structural analogue of necrostatin-1. Necrostatin-1 also limited cell death by 48%, reduced blood-brain barrier opening by 51%, attenuated edema development to sham levels, and improved neurobehavioral outcomes after ICH. These data suggest a potential clinical utility for necrostatin-1 and/or novel necroptosis inhibitors as an adjunct therapy to reduce neurological injury and improve patient outcomes after ICH.

Transplantation of neural stem cells that overexpress SOD1 enhances amelioration of intracerebral hemorrhage in mice

Previous studies have shown that intraparenchymal transplantation of neural stem cells (NSCs) ameliorates neurologic deficits in animals with intracerebral hemorrhage (ICH). However, massive grafted cell death after transplantation, possibly caused by a hostile host brain environment, lessens the effectiveness of this approach. We focused on the effect of oxidative stress against grafted NSCs and hypothesized that conferring antioxidant properties to transplanted NSCs may overcome their death and enhance neuroprotection after ICH. Copper/zinc-superoxide dismutase (SOD1) is a specific antioxidant enzyme that counteracts superoxide anions. We investigated whether genetic manipulation to overexpress SOD1 enhances survival of grafted NSCs and accelerates amelioration of ICH. Neural stem cells that overexpress SOD1 were administered intracerebrally 3 days after ICH in a mouse model. Histologic and behavioral tests were examined after ICH. Copper/zinc-superoxide dismutase overexpression protected the grafted NSCs via a decrease in production of reactive oxygen species. This resulted in an increase in paracrine factors released by the NSCs, and an increase in surviving neurons in the striatum and a reduction in striatal atrophy. In addition, SOD1 overexpression showed progressive improvement in behavioral recovery. Our results suggest that enhanced antioxidative activity in NSCs improves efficacy of stem cell therapy for ICH.

A neuroproteomic and systems biology analysis of rat brain post intracerebral hemorrhagic stroke

Intracerebral hemorrhage (ICH) is a devastating form of stroke leading to a high rate of death and disability worldwide. Although it has been hypothesized that much of the IHC insult occurs in the subacute period mediated via a series of complex pathophysiological cascades, the molecular mechanisms involved in ICH have not been systematically characterized. Among the best approaches to understand the underlying mechanisms of injury and recovery, protein dynamics assessment via proteomics/systems biology platforms represent one of the cardinal techniques optimized for mechanisms investigation and biomarker identification. A proteomics approach may provide a biomarker focused framework from which to identify candidate biomarkers of pathophysiological processes involved in brain injury after stroke. In this work, a neuroproteomic approach (LC-MS/MS) was applied to investigate altered expression of proteins that are induced in brain tissue 3 h after injury in a rat model of ICH. Data from sham and focal ischemic models were also obtained and used for comparison. Based on the differentially expressed protein profile, systems biology analysis was conducted to identify associated cellular processes and related interaction maps. After LC-MS/MS analysis of the 3 h brain lysates, 86 proteins were differentially expressed between hemorrhagic and sham tissues. Furthermore, 38 proteins were differentially expressed between ischemic and sham tissues. On the level of global pathway analysis, hemorrhagic stroke proteins were shown to be involved in autophagy, ischemia, necrosis, apoptosis, calpain activation, and cytokine secretion. Moreover, ischemic stroke proteins were related to cell death, ischemia, inflammation, oxidative stress, caspase activation and apoptotic injury. In conclusion, the proteomic responses identified in this study provide key information about target proteins involved in specific pathological pathways.

NLRP3 inflammasome contributes to inflammation after intracerebral hemorrhage

OBJECTIVE

The NLRP3 (NALP3, cryopyrin) inflammasome, a key component of the innate immune system, facilitates caspase-1 and interleukin (IL)-1β processing, which amplifies the inflammatory response. Here, we investigated whether NLRP3 knockdown decreases neutrophil infiltration, reduces brain edema, and improves neurological function in an intracerebral hemorrhage (ICH) mouse model. We also determined whether mitochondrial reactive oxygen species (ROS) governed by mitochondrial permeability transition pores (mPTPs) would trigger NLRP3 inflammasome activation following ICH.

METHODS

ICH was induced by injecting autologous arterial blood (30μl) into a mouse brain. NLRP3 small interfering RNAs were administered 24 hours before ICH. A mPTP inhibitor (TRO-19622) or a specific mitochondria ROS scavenger (Mito-TEMPO) was coinjected with the blood. In naive animals, rotenone, which is a respiration chain complex I inhibitor, was applied to induce mitochondrial ROS production, and followed by TRO-19622 or Mito-TEMPO treatment. Neurological deficits, brain edema, enzyme-linked immunosorbent assay, Western blot, in vivo chemical cross-linking, ROS assay, and immunofluorescence were evaluated.

RESULTS

ICH activated the NLRP3 inflammasome. NLRP3 knockdown reduced brain edema and decreased myeloperoxidase (MPO) levels at 24 hours, and improved neurological functions from 24 to 72 hours following ICH. TRO-19622 or Mito-TEMPO reduced ROS, NLRP3 inflammasome components, and MPO levels following ICH. In naive animals, rotenone administration induced mPTP formation, ROS generation, and NLRP3 inflammasome activation, which were then reduced by TRO-19622 or Mito-TEMPO.

INTERPRETATION

The NLRP3 inflammasome amplified the inflammatory response by releasing IL-1β and promoting neutrophil infiltration following ICH. Mitochondria ROS may be a major trigger of NLRP3 inflammasome activation. The results of our study suggest that the inhibition of the NLRP3 inflammasome may effectively reduce the inflammatory response following ICH.ANN NEUROL 2014;75:209-219.

Perispinal etanercept for post-stroke neurological and cognitive dysfunction: scientific rationale and current evidence

There is increasing recognition of the involvement of the immune signaling molecule, tumor necrosis factor (TNF), in the pathophysiology of stroke and chronic brain dysfunction. TNF plays an important role both in modulating synaptic function and in the pathogenesis of neuropathic pain. Etanercept is a recombinant therapeutic that neutralizes pathologic levels of TNF. Brain imaging has demonstrated chronic intracerebral microglial activation and neuroinflammation following stroke and other forms of acute brain injury. Activated microglia release TNF, which mediates neurotoxicity in the stroke penumbra. Recent observational studies have reported rapid and sustained improvement in chronic post-stroke neurological and cognitive dysfunction following perispinal administration of etanercept. The biological plausibility of these results is supported by independent evidence demonstrating reduction in cognitive dysfunction, neuropathic pain, and microglial activation following the use of etanercept, as well as multiple studies reporting improvement in stroke outcome and cognitive impairment following therapeutic strategies designed to inhibit TNF. The causal association between etanercept treatment and reduction in post-stroke disability satisfy all of the Bradford Hill Criteria: strength of the association; consistency; specificity; temporality; biological gradient; biological plausibility; coherence; experimental evidence; and analogy. Recognition that chronic microglial activation and pathologic TNF concentration are targets that may be therapeutically addressed for years following stroke and other forms of acute brain injury provides an exciting new direction for research and treatment.

Gene expression profiling of blood in brain arteriovenous malformation patients

Brain arteriovenous malformations (BAVMs) are an important cause of intracranial hemorrhage (ICH) in young adults. Gene expression profiling of blood has led to the identification of stroke biomarkers, and may help identify BAVM biomarkers and illuminate BAVM pathogenesis. It is unknown whether blood gene expression profiles differ between 1) BAVM patients and healthy controls, or 2) unruptured and ruptured BAVM patients at presentation. We characterized blood transcriptional profiles in 60 subjects (20 unruptured BAVM, 20 ruptured BAVM, and 20 healthy controls) using Affymetrix whole genome expression arrays. Expression differences between groups were tested by ANOVA, adjusting for potential confounders. Genes with absolute fold change ≥ 1.2 (false discovery rate corrected p ≤ 0.1) were selected as differentially expressed and evaluated for over-representation in KEGG biological pathways (p ≤ 0.05). Twenty-nine genes were differentially expressed between unruptured BAVM patients and controls, including 13 which may be predictive of BAVM. Patients with ruptured BAVM compared to unruptured BAVM differed in expression of 1490 genes, with over-representation of genes in 8 pathways including MAPK, VEGF, Wnt signaling and several inflammatory pathways. These results suggest clues to the pathogenesis of BAVM and/or BAVM rupture and point to potential biomarkers or new treatment targets.

Polybutylcyanoacrylate nanoparticles for delivering hormone response element-conjugated neurotrophin-3 to the brain of intracerebral hemorrhagic rats

Hypertensive intracerebral hemorrhage (ICH) is a rapidly evolutional pathology, inducing necrotic cell death followed by apoptosis, and alters gene expression levels in surrounding tissue of an injured brain. For ICH therapy by controlled gene release, the development of intravenously administrable delivery vectors to promote the penetration across the blood-brain barrier (BBB) is a critical challenge. To enhance transfer efficiency of genetic materials under hypoxic conditions, polybutylcyanoacrylate (PBCA) nanoparticles (NPs) were used to mediate the intracellular transport of plasmid neurotrophin-3 (NT-3) containing hormone response element (HRE) with a cytomegalovirus (cmv) promoter and to differentiate induced pluripotent stem cells (iPSCs). The differentiation ability of iPSCs to neurons was justified by various immunological stains for protein fluorescence. The effect of PBCA NP/cmvNT-3-HRE complexes on treating ICH rats was studied by immunostaining, western blotting and Nissl staining. We found that the treatments with PBCA NP/cmvNT-3-HRE complexes increased the capability of differentiating iPSCs to express NT-3, TrkC and MAP-2. Moreover, PBCA NPs could protect cmvNT-3-HRE against degradation with EcoRI/PstI and DNase I in vitro and raise the delivery across the BBB in vivo. The administration of PBCA NP/cmvNT-3-HRE complexes increased the expression of NT-3, inhibited the expression of apoptosis-inducing factor, cleaved caspase-3 and DNA fragmentation, and reduced the cell death rate after ICH in vivo. PBCA NPs are demonstrated as an appropriate delivery system for carrying cmvNT-3-HRE to the brain for ICH therapy.

Intracerebral haemorrhage: mechanisms of injury and therapeutic targets

Intracerebral haemorrhage accounts for about 10-15% of all strokes and is associated with high mortality and morbidity. No successful phase 3 clinical trials for this disorder have been completed. In the past 6 years, the number of preclinical and clinical studies focused on intracerebral haemorrhage has risen. Important advances have been made in animal models of this disorder and in our understanding of mechanisms underlying brain injury after haemorrhage. Several therapeutic targets have subsequently been identified that are now being pursued in clinical trials. Many clinical trials have been based on limited preclinical data, and guidelines to justify taking preclinical results to the clinic are needed.

The Molecular Mechanisms that Promote Edema After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating type of stroke with no effective therapies. Clinical advances in ICH treatment are limited by an incomplete understanding of the molecular mechanisms responsible for secondary injury and poor outcome. Increasing evidence suggests that cerebral edema is a major contributor to secondary injury and poor outcome in ICH. ICH activates specific signaling pathways that promote edema and damage neuronal tissue. By increasing our understanding of these pathways, we may be able to target them pharmaceutically to reduce edema in ICH patients. In this review, we focus on three major signaling pathways that promote edema after ICH: (1) the coagulation cascade and thrombin, (2) the inflammatory response and matrix metalloproteinases, and (3) the complement cascade and hemoglobin toxicity. We will describe the experimental evidence that confirms these pathways promote edema in ICH, discuss potential targets for new therapies, and comment on important directions for future research.

Chemokines and their receptors in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating clinical event which results in a high rate of disability and death. At present, no effective treatment is available for ICH. Accumulating evidence suggests that inflammatory responses contribute significantly to the ICH-induced secondary brain outcomes. During ICH, inflammatory cells accumulate at the ICH site attracted by gradients of chemokines. This review summarizes recent progress in ICH studies and the chemoattractants that act during the injury and focuses on and introduces the basic biology of the chemokine monocyte chemoattractant protein-1 (MCP1) and its role in the progression of ICH. Better understanding of MCP1 signaling cascade and the compensation after its inhibition could shed light on the development of effective treatments for ICH.

Age-related comparisons of evolution of the inflammatory response after intracerebral hemorrhage in rats

In the hours to days after intracerebral hemorrhage (ICH), there is an inflammatory response within the brain characterized by the infiltration of peripheral neutrophils and macrophages and the activation of brain-resident microglia and astrocytes. Despite the strong correlation of aging and ICH incidence, and increasing information about cellular responses, little is known about the temporal- and age-related molecular responses of the brain after ICH. Here, we monitored a panel of 27 genes at 6 h and 1, 3, and 7 days after ICH was induced by injecting collagenase into the striatum of young adult and aged rats. Several molecules (CR3, TLR2, TLR4, IL-1β, TNFα, iNOS, IL-6) were selected to reflect the classical activation of innate immune cells (macrophages, microglia) and the potential to exacerbate inflammation and damage brain cells. Most of the others are associated with the resolution of innate inflammation, alternative pathways of macrophage/microglial activation, and the repair phase after acute injury (TGFβ, IL-1ra, IL-1r2, IL-4, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22). In young animals, the up-regulation of 26 in 27 genes (not IL-4) was detected within the first week. Differences in timing or levels between young and aged animals were detected for 18 of 27 genes examined (TLR2, GFAP, IL-1β, IL-1ra, IL-1r2, iNOS, IL-6, TGFβ, MMP9, MMP12, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22), with a generally less pronounced or delayed inflammatory response in the aged animals. Importantly, within this complex response to experimental ICH, the induction of pro-inflammatory, potentially harmful mediators often coincided with resolving and beneficial molecules.