Intercellular cross-talk in intracerebral hemorrhage

MiRNAs as potential therapeutic targets and biomarkers for non-traumatic intracerebral hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Hypertension is most often the cause of ICH. Less often, atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication, vitamin deficiencies, and other reasons cause hemorrhages. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. This very dangerous disease is difficult to treat, requires surgery and can lead to disability or death. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that are involved in a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., through gene repression. A growing number of studies have demonstrated miRNAs deregulation in various cardiovascular diseases, including ICH. In addition, given that computed tomography (CT) and/or magnetic resonance imaging (MRI) are either not available or do not show clear signs of possible vessel rupture, accurate and reliable analysis of circulating miRNAs in biological fluids can help in early diagnosis for prevention of ICH and prognosis patient outcome after hemorrhage. In this review, we highlight the up-to-date findings on the deregulated miRNAs in ICH, and the potential use of miRNAs in clinical settings, such as therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

PPARγ/RAD21 alleviates peripheral secondary brain injury in rat cerebral hemorrhage model through promoting M2 polarization of microglial cells

BACKGROUND

PPARγ has been reported to participate in intracerebral hemorrhage (ICH) progression, and recruit RAD21 through binding DNA. Our study aimed to explore the roles of PPARγ/RAD21 in ICH and their related mechanisms.

METHODS

ICH models in vitro and in vivo were established using thrombin and autologous blood injection, respectively. After that, rosiglitazone (RSG), GW9662, and RAD21 knockdown/overexpression plasmids were used to treat the ICH models. The cell apoptosis, the related inflammatory cytokines levels, and the neurological function of the rats were examined. Real-time quantitative PCR (RT-qPCR), western blot and immunofluorescence were employed to determine the expression of the M1/M2 polarization-related markers. Finally, the interaction of PPARγ and RAD21 in microglial cells was observed using double labeled immunofluorescence and co-immunoprecipitation.

RESULTS

After thrombin induction, the cell apoptosis, and TNF-α, IL-1β and IL-10 contents were all significantly increased (P < 0.05); whereas RSG and RAD21 overexpression evidently inhibited the apoptosis of thrombin-caused microglial cells, reduced TNF-α and IL-1β contents, further increased IL-10 content (P < 0.05). The combination of RAD21 and PPARγ was enhanced by RSG and RAD21 overexpression. In vivo experiments showed that RSG and RAD21 overexpression decreased neurological deficit score, brain water content and hematoma volume. Additionally, RSG and RAD21 overexpression up-regulated the expression of PPARγ, RAD21, Arg1, KLF4, and TGF-β, whereas down-regulated iNOS and CD32 expression. The actions of GW9662 and RAD21 knockdown were opposite to those of RSG and RAD21 overexpression.

CONCLUSION

PPARγ/RAD21 may alleviate ICH progression through promoting M2-type polarization of microglial cells and inhibiting inflammatory response.

Synthesis and Development of a Novel First-in-Class Cofilin Inhibitor for Neuroinflammation in Hemorrhagic Brain Injury

Intracerebral hemorrhage (ICH) is devastating among stroke types with high mortality. To date, not a single therapeutic intervention has been successful. Cofilin plays a critical role in inflammation and cell death. In the current study, we embarked on designing and synthesizing a first-in-class small-molecule inhibitor of cofilin to target secondary complications of ICH, mainly neuroinflammation. A series of compounds were synthesized, and two lead compounds SZ-3 and SK-1-32 were selected for further studies. Neuronal and microglial viabilities were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay using neuroblastoma (SHSY-5Y) and human microglial (HMC-3) cell lines, respectively. Lipopolysaccharide (LPS)-induced inflammation in HMC-3 cells was used for neurotoxicity assay. Other assays include nitric oxide (NO) by Griess reagent, cofilin inhibition by F-actin depolymerization, migration by scratch wound assay, tumor necrosis factor (TNF-α) by enzyme-linked immunosorbent assay (ELISA), protease-activated receptor-1 (PAR-1) by immunocytochemistry and Western blotting (WB), and protein expression levels of several proteins by WB. SK-1-32 increased neuronal/microglial survival, reduced NO, and prevented neurotoxicity. However, SZ-3 showed no effect on neuronal/microglial survival but prevented microglia from LPS-induced inflammation by decreasing NO and preventing neurotoxicity. Therefore, we selected SZ-3 for further molecular studies, as it showed potent anti-inflammatory activities. SZ-3 decreased cofilin severing activity, and its treatment of LPS-activated HMC-3 cells attenuated microglial activation and suppressed migration and proliferation. HMC-3 cells subjected to thrombin, as an in vitro model for hemorrhagic stroke, and treated with SZ-3 after 3 h showed significantly decreased NO and TNF-α, significantly increased protein expression of phosphocofilin, and decreased PAR-1. In addition, SZ-3-treated SHSY-5Y showed a significant increase in cell viability by significantly reducing nuclear factor-κ B (NF-κB), caspase-3, and high-temperature requirement (HtrA2). Together, our results support the novel idea of targeting cofilin to counter neuroinflammation during secondary injury following ICH.

The neuroprotective effect of phillyrin in intracerebral hemorrhagic mice is produced by activation of the Nrf2 signaling pathway

Phillyrin, a natural plant extract, has significant antioxidant and anti-apoptotic effects. However, its effect on intracerebral hemorrhage (ICH) remains unclear. In this study, we investigated a potential role for phillyrin in the regulation of the oxidative stress and apoptosis induced by ICH. A model of ICH was induced by collagenase IV (0.2 U in 1 μl sterile normal saline) in male C57BL/6J (B6) mice and different doses of phillyrin (5, 15, or 30 mg/kg) were intraperitoneally (i.p.) injected at 30 min, 6 h, and 22 h after modeling. We found that phillyrin significantly reduced neural function and lesion volume, improved injury of white and grey matter around the lesion, decreased apoptosis and oxidative stress, increased the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase 1(HO-1), NADPH quinone oxidoreductase 1 (NQO1) and Superoxide Dismutase-1(SOD-1) in vitro and in vivo, and protected neurons from the stimulation of hemin by promoting Nrf2 nuclear translocation. Treatment with ML385 (Nrf2 inhibitor) completely reversed the protective effects of phillyrin in vivo after ICH injury. Based on our findings, we conclude that phillyrin treatment alleviates ICH injury-induced apoptosis and oxidative stress via activation of the Nrf2 signaling pathway, highlighting a potential role for phillyrin as an ICH therapeutic.

Assessing early erythrolysis and the relationship to perihematomal iron overload and white matter survival in human intracerebral hemorrhage

AIMS

Iron released from lysed red blood cells within the hematoma plays a role in intracerebral hemorrhage (ICH)-related neurotoxicity. This study utilizes magnetic resonance imaging (MRI) to examine the time course, extent of erythrolysis, and its correlation with perihematomal iron accumulation and white matter loss.

METHODS

The feasibility of assessing proportional erythrolysis using T2* MRI was examined using pig blood phantoms with specified degrees of erythrolysis. Fifteen prospectively enrolled ICH patients had MRIs (3-Tesla) at days 1-3, 14, and 30 (termed early, subacute, and late periods, respectively). Measurement was performed on T2*, 1/T2*, and fractional anisotropy (FA) maps.

RESULTS

Pig blood phantoms showed a linear relationship between 1/T2* signal and percent erythrolysis. MRI on patients showed an increase in erythrolysis within the hematoma between the early and subacute phases after ICH, almost completing by day 14. Although perihematomal iron overload (IO) correlated with the erythrolysis extent and hematoma volume at days 14 and 30, perihematomal white matter (WM) loss significantly correlated with both, only at day 14.

CONCLUSION

MRI may reliably assess the portion of the hematoma that lyses over time after ICH. Perihematomal IO and WM loss correlate with both the erythrolysis extent and hematoma volume in the early and subacute periods following ICH.

The Role of NLRP3 Inflammasome in Cerebrovascular Diseases Pathology and Possible Therapeutic Targets

Cerebrovascular diseases are pathological conditions involving impaired blood flow in the brain, primarily including ischaemic stroke, intracranial haemorrhage, and subarachnoid haemorrhage. The nucleotide-binding and oligomerisation (NOD) domain-like receptor (NLR) family pyrin domain (PYD)-containing 3 (NLRP3) inflammasome is a protein complex and a vital component of the immune system. Emerging evidence has indicated that the NLRP3 inflammasome plays an important role in cerebrovascular diseases. The function of the NLRP3 inflammasome in the pathogenesis of cerebrovascular diseases remains an interesting field of research. In this review, we first summarised the pathological mechanism of cerebrovascular diseases and the pathological mechanism of the NLRP3 inflammasome in aggravating atherosclerosis and cerebrovascular diseases. Second, we outlined signalling pathways through which the NLRP3 inflammasome participates in aggravating or mitigating cerebrovascular diseases. Reactive oxygen species (ROS)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), ROS/thioredoxin-interacting protein (TXNIP) and purinergic receptor-7 (P2X7R) signalling pathways can activate the NLRP3 inflammasome; activation of the NLRP3 inflammasome can aggravate cerebrovascular diseases by mediating apoptosis and pyroptosis. Autophagy/mitochondrial autophagy, nuclear factor E2-related factor-2 (Nrf2), interferon (IFN)-β, sirtuin (SIRT), and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) reportedly alleviate cerebrovascular diseases by inhibiting NLRP3 inflammasome activation. Finally, we explored specific inhibitors of the NLRP3 inflammasome based on the two-step activation of the NLRP3 inflammasome, which can be developed as new drugs to treat cerebrovascular diseases.

Albumin Reduces Oxidative Stress and Neuronal Apoptosis via the ERK/Nrf2/HO-1 Pathway after Intracerebral Hemorrhage in Rats

BACKGROUND

Albumin has been regarded as a potent antioxidant with free radical scavenging activities. Oxidative stress and neuronal apoptosis are responsible for its highly damaging effects on brain injury after intracerebral hemorrhage (ICH). Here, the present study investigated the neuroprotective effect of albumin against early brain injury after ICH and the potential underlying mechanisms.

METHODS

Adult male Sprague-Dawley rats were subjected to intrastriatal injection of autologous blood to induce ICH. Human serum albumin was given by intravenous injection 1 h after ICH. U0126, an inhibitor of extracellular signal-regulated kinase (ERK1/2), and ML385, an inhibitor of nuclear factor-E2-related factor 2 (Nrf2), were intraperitoneally administered 1 h before ICH induction. Short- and long-term neurobehavioral tests, western blotting, immunofluorescence staining, oxidative stress evaluations, and apoptosis measurements were performed.

RESULTS

Endogenous expression of albumin (peaked at 5 days) and heme oxygenase 1 (HO-1, peaked at 24 h) was increased after ICH compared with the sham group. Albumin and HO-1 were colocalized with neurons. Compared with vehicle, albumin treatment significantly improved short- and long-term neurobehavioral deficits and reduced oxidative stress and neuronal death at 72 h after ICH. Moreover, albumin treatment significantly promoted the phosphorylation of ERK1/2; increased the expression of Nrf2, HO-1, and Bcl-2; and downregulated the expression of Romo1 and Bax. U0126 and ML385 abolished the treatment effects of albumin on behavior and protein levels after ICH.

CONCLUSIONS

Albumin attenuated oxidative stress-related neuronal death may in part via the ERK/Nrf2/HO-1 signaling pathway after ICH in rats. Our study suggests that albumin may be a novel therapeutic method to ameliorate brain injury after ICH.

The Blood Component Iron Causes Neuronal Apoptosis Following Intracerebral Hemorrhage via the PERK Pathway

PERK signaling pathway plays an important role in neuronal apoptosis after Intracerebral hemorrhage (ICH). ICH can cause the release of blood components into the brain. However, which component in the blood plays a major role still unclear. This study was designed to investigate the activation of the PERK pathway in different blood components after ICH and explore which components have major relationships with neuronal apoptosis. Eighty-five Sprague-Dawley rats were used to establish an ICH model. Western blot (WB) and immunofluorescence (IF) were used to evaluate the expression of the PERK pathway. TUNEL staining, FJC staining and neurological score were used to evaluate neuronal apoptosis and necrosis after ICH. The results showed that protein levels of p-PERK and p-eIF2α were upregulated following ICH with the injection of Fe³⁺ and Fe²⁺ after 48 h. Then, deferoxamine (DFX) was used to study the roles of Fe³⁺ in ICH through the PERK signaling pathway. The results showed that injection of DFX reversed increasing protein levels and prevented neuronal apoptosis. Thus, iron plays an important role in ICH through the PERK signaling pathway. Furthermore, the reduction of iron demonstrates neuroprotective effects in ICH. This suggests that targeting intervention of the iron and PERK pathway could be an effective treatment strategy to improve ICH prognosis.

Proteomic Analysis of Perihematoma Tissue from Patients with Intracerebral Hemorrhage Using iTRAQ-Based Quantitative Proteomics

Intracerebral hemorrhage is a complicated disorder with limited proven prognostic and therapeutic targets and elusive mechanisms. With proteomic methods, we aimed to explore the global protein expression profile of perihematomal tissue from ICH patients and identify potential pathophysiological pathways and protein markers. Using iTRAQ-labeling quantitative proteomics technology, four ICH brain sample and four non-ICH brain samples were analyzed. Among the 3740 quantifiable proteins, 884 were dysregulated in the patients compared to those in the controls (p < 0.05). After bioinformatics analysis, the differentially expressed proteins were found to be mostly involved in hemostatic processes, nutrient metabolism signaling pathways, and antioxidation pathways. Moreover, fibronectin 1 was revealed to be at the center of the protein-protein interaction networks. In summary, the potential pathways and brain protein markers that could potentially be used to predict the prognosis of ICH were obtained from the altered proteomic profile of perihematomal tissue. Thus, these data may yield novel insights into the mechanisms of ICH-induced secondary brain injury.

Protocatechuic acid attenuates brain edema and blood-brain barrier disruption after intracerebral hemorrhage in mice by promoting Nrf2/HO-1 pathway

The brain edema following intracerebral hemorrhage (ICH) plays a key role in the recovery process. Protocatechuic acid (PCA) has been proved possessing neuroprotection in ICH. Here we tried to explore its value in brain edema after ICH and reveal underlying mechanisms. ICH model was created in C57 mice using collagenase IV. PCA was injected intraperitoneally at 30 mg/kg every 24 h in PCA group. On day 3 after ICH, the water content of hemorrhagic ipsilateral hemisphere in PCA group was significantly reduced compared with vehicle group. AQP4, the main water channel, was remarkably decreased in PCA group. Additionally, ZO-1 and occludin expression were increased in PCA group. The bEnd.3 cells were cultured to understand the effect of PCA on the blood-brain barrier (BBB) integrity. Compare to hemin treated group, plus PCA enhanced the expression of HO-1 and Nrf2 nuclear translocation. Furtherly, the overexpression of HO-1, ZO-1, occludin, in the PCA treatment group was inhibited after knockdown of Nrf2. Taken together, our results proved PCA alleviated brain edema and BBB disruption in ICH by promoting the Nrf2/HO-1 signaling pathway.

Wogonin Accelerates Hematoma Clearance and Improves Neurological Outcome via the PPAR-γ Pathway After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a cerebrovascular disease with high mortality and morbidity for which effective treatments are currently lacking. Wogonin is a major flavonoid compound isolated from Scutellaria radix. Accumulating evidence suggests that wogonin plays a crucial role in anti-inflammatory and anti-oxidative stress. Treatment of microglia with nuclear receptor agonists augments the expression of phagocytosis-related genes. However, the neuroprotective effects of wogonin in ICH remain obscure. In this study, we elucidated an innovative mechanism by which wogonin acts to enhance phagocytosis in a murine model of ICH. Wogonin promoted hematoma clearance and improved neurological recovery after ICH by upregulating the expression of Axl, MerTK, CD36, and LAMP2 in perihematomal microglia and BV2 cells. Treatment of a murine model of ICH with wogonin stimulated microglial phagocytosis in vitro. Further, we demonstrated that wogonin dramatically attenuated inflammatory and oxidative stress responses in a murine model of ICH by reducing the expression of pro-inflammatory cytokines and pro-oxidant enzymes such as TNF-α, IL-1β, and inducible nitric oxide synthase (iNOS) after ICH. The effects of wogonin were abolished by administration of the PPAR-γ inhibitor GW9662. In conclusion, our data suggest that wogonin facilitates hematoma clearance and neurobehavioral recovery by targeting PPAR-γ.

Neuroinflammation Mediated by NLRP3 Inflammasome After Intracerebral Hemorrhage and Potential Therapeutic Targets

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke; there is still a lack of effective treatment. Microglia are a major component of the innate immune system, and they respond to acute brain injury by activating and forming classic M1-like (pro-inflammatory) or alternative M2-like (anti-inflammatory) phenotype. The existence of the polarization indicates that the role of microglia in disease's progression and recovery after ICH is still unclear, perhaps involving microglial secretion of anti-inflammatory or pro-inflammatory cytokines and chemokines. The NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome is considered to be the main participant in neuroinflammation. Recent evidence has shown that NLRP3 inflammasome can be activated after ICH, resulting in inflammatory cascade reactions and aggravating brain injury. Furthermore, previous studies have reported that NLRP3 inflammasome is mainly present in microglia, so we speculate that its activation may be strongly associated with microglial polarization. Many scholars have investigated the role of brain injury caused by NLRP3 inflammasome after ICH, but the precise operating mechanisms remain uncertain. This review summarized the activation mechanism of NLRP3 inflammasome after ICH and the possible mechanism of NLRP3 inflammasome promoting neuroinflammation and aggravating nerve injury and discussed the relevant potential therapeutic targets.

Loss of mural cell-derived laminin aggravates hemorrhagic brain injury

Background

Mural cells synthesize and deposit laminin to the basement membrane. To investigate the function of mural cell-derived laminin, we generated a mutant mouse line lacking mural cell-derived laminin (termed PKO). In a previous study, we showed that the PKO mice were grossly normal under homeostatic condition, but developed blood-brain barrier (BBB) breakdown with advanced age (> 8 months), suggesting that these mutants are intrinsically weak. Based on these findings, we hypothesized that PKO mice have exacerbated injuries in pathological conditions.

Methods

Using collagenase-induced intracerebral hemorrhage (ICH) as an injury model, we examined various stroke outcomes, including hematoma volume, neurological function, neuronal death, BBB integrity, paracellular/transcellular transport, inflammatory cell infiltration, and brain water content, in PKO mice and their wildtype littermates at young age (6–8 weeks). In addition, transmission electron microscopy (TEM) analysis and an in vitro ICH model were used to investigate the underlying molecular mechanisms.

Results

Compared to age-matched wildtype littermates, PKO mice display aggravated stroke outcomes, including larger hematoma size, worse neurological function, increased neuronal cell death, enhanced BBB permeability, increased transcytosis, and elevated inflammatory cell infiltration. These mutants also exhibit high baseline brain water content independent of aquaporin-4 (AQP4). In addition, mural cell-derived laminin significantly reduced caveolin-1 without affecting tight junction proteins in the in vitro ICH model.

Conclusions

These results suggest that mural cell-derived laminin attenuates BBB damage in ICH via decreasing caveolin-1 and thus transcytosis, regulates brain water homeostasis, and plays a beneficial role in ICH.

Genetic Relationship Between Endothelin-1 Gene Polymorphisms and Intracerebral Hemorrhage Among Chinese Han People

Background

The goal of the present study was to determine whether endothelin-1 (EDN1) variants are associated with intracerebral hemorrhage (ICH) risk among Chinese Han people.

Material/Methods

The genotyping of EDN1 rs5370 and rs6458155 polymorphisms were conducted in 154 ICH patients and 168 healthy controls using polymerase chain reaction (PCR) and sequencing. Deviation for genotype frequencies in controls from Hardy-Weinberg equilibrium (HWE) was assessed. The genotype and allele distribution of EDN1 polymorphisms was checked via χ² test between 2 groups. Strength of the association between EDN1 polymorphisms and ICH risk is presented by odds ratio (OR) and 95% confidence interval (95% CI).

Results

Genotype distribution for rs5370 and rs6458155 polymorphisms in the control group both conformed to HWE (P>0.05). Only CC genotype and C allele frequencies of rs6458155 between ICH patients and healthy individuals were significantly different (P=0.025; P=0.043), indicating rs64581255 is associated with increased ICH onset (OR=2.214, 95% CI=1.009–4.461; OR=1.389, 95% CI=1.010–1.910). When adjusted by confounding factors, the significant correlations still existed between 2 groups (P=0.028, adjusted OR=2.217, 95% CI=1.092–4.500; P=0.046, adjusted OR=1.386, 95% CI=1.005–1.910).

Conclusions

EDN1 rs6458155 polymorphism may be a risk factor of ICH among Chinese Han people.

Spleen associated immune-response mediates brain-heart interaction after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) patients frequently encounter cardiovascular complications which may contribute to increased mortality and poor long term outcome. ICH induces systemic oxidative stress and activates peripheral immune responses which are involved in the pathological cascade leading to cardiac dysfunction and heart failure after ICH. We have previously reported that ICH induces progressive cardiac dysfunction in mice without primary cardiac diseases. In this study, we have investigated the role of immune response in mediating cardiac dysfunction post ICH in mice.

METHODS

Adult male C57BL/6 J mice were randomly assigned to the following groups (n = 8/group): 1) sham control; 2) ICH; 3) splenectomy with ICH (ICH + Spx); 4) splenectomy alone (Spx). Echocardiography was performed at 7 and 28 days after ICH. A battery of neurological and cognitive tests were performed. Flow cytometry, western blot and immunostaining were used to test mechanisms of ICH induced cardiac dysfunction.

RESULTS

Compared to sham control mice, Spx alone does not induce acute (7 day) or chronic (28 day) cardiac dysfunction. ICH induces significant neurological and cognitive deficits, as well as acute and chronic cardiac dysfunction compared to sham control mice. Mice subjected to ICH + Spx exhibit significantly improved neurological and cognitive function compared to ICH mice. Mice with ICH + Spx also exhibit significantly improved acute and chronic cardiac function compared to ICH mice indicated by increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS), decreased cardiac fibrosis, decreased cardiomyocyte hypertrophy, decreased cardiac infiltration of immune cells and decreased expression of inflammatory factor and oxidative stress in the heart.

CONCLUSIONS

Our study demonstrates that splenectomy attenuates ICH-induced neurological and cognitive impairment as well as ICH-induced cardiac dysfunction in mice. Inflammatory cell infiltration into heart and immune responses mediated by the spleen may contribute to ICH-induce acute and chronic cardiac dysfunction and pathological cardiac remodeling.

Inhibition of activator protein 1 attenuates neuroinflammation and brain injury after experimental intracerebral hemorrhage

Aims

Intracerebral hemorrhage (ICH) is a devastating type of stroke without specific treatment. Activator protein 1 (AP‐1), as a gene regulator, initiates cytokine expression in response to environmental stimuli. In this study, we investigated the relationship between AP‐1 and neuroinflammation‐associated brain injury triggered by ICH.

Methods

Intracerebral hemorrhage mice were developed by autologous blood or collagenase infusion. We measured the dynamics of AP‐1 in mouse brain tissues during neuroinflammation formation after ICH. The effects of the AP‐1 inhibitor SR11302 on brain injury and neuroinflammation as well as the underlying mechanisms were investigated in vivo and in vitro.

Results

AP‐1 was significantly upregulated in mouse brain tissue as early as 6 hours after ICH, accompanied by elevations in proinflammatory factors, including interleukin (IL)‐6, IL‐1β, and tumor necrosis factor (TNF)‐α. Inhibition of AP‐1 using SR11302 reduced neurodeficits and brain edema at day 3 after ICH. SR11302 ablated microglial IL‐6 and TNF‐α production and brain‐infiltrating leukocytes in ICH mice. In addition, SR11302 treatment diminished thrombin‐induced production of IL‐6 and TNF‐α in cultured microglia.

Conclusions

Inhibition of AP‐1 curbs neuroinflammation and reduces brain injury following ICH.

Lithium chloride promoted hematoma resolution after intracerebral hemorrhage through GSK-3β-mediated pathways-dependent microglia phagocytosis and M2-phenotype differentiation, angiogenesis and neurogenesis in a rat model

Some neuroprotective agents have been used clinically to address the resulting various adverse effects after intracerebral hemorrhage (ICH). Particularly, effectively removing the hematoma is of practical significance to exert neuroprotective effects following ICH. However, such agents are still in need of development. Lithium chloride (LiCl) has shown neuroprotective effects through glycogen synthase kinase-3β (GSK-3β) inhibition in a variety of central nervous system diseases. However, the impact of LiCl on hematoma clearance and the potential molecular mechanisms have not been reported. We hypothesize that LiCl may exert neuroprotective roles after ICH, partly through promoting hematoma resolution. In this study, male Sprague-Dawley rats were subjected to ICH followed by intraperitoneal injection of LiCl (60 mg/kg). The hematoma volumes of ipsilateral hemisphere were determined using Drabkin's method. The sensorimotor deficits were evaluated by neurobehavioral tests. The expressions of target molecules involved in the process of hematoma clearance were assayed using immunofluorescence and Western blot. Our results showed that animals treated with LiCl presented significantly reduced hematoma volume after ICH, which was coupled with enhanced microglia phagocytosis and its differentiation into M2-phenotype within the first 7 days and up-regulated angiogenesis and neurogenesis in the next 7 days. Meanwhile, GSK-3β was inhibited by LiCl and β-catenin became stabilized, which was followed by up-regulation of nuclear factor erythroid 2-related factor 2 and CD36 from days 3 to 7, and increase of vascular endothelial growth factor and brain-derived neurotrophic factor from days 7 to 14. These data suggest that LiCl promotes hematoma resolution via enhancing microglia phagocytosis and M2-phenotype differentiation in the early stage (< 7 days) and angiogenesis and neurogenesis in the chronic phase (days 7-14), thus eventually improving the functional outcomes of ICH rats.

Long-Term Follow-up in Patients with Spontaneous Intracerebral Hemorrhage Treated With or Without Surgical Intervention: a Large-Scale Retrospective Study

Debates regarding the most beneficial medical or surgical procedures for patients with spontaneous intracerebral hemorrhage (sICH) are still ongoing. We aimed to evaluate the risk of subsequent vascular disease and mortality in patients with sICH treated with and without surgical intervention, in a large-scale Asian population. Patients hospitalized within 2000 to 2013 who were newly diagnosed with sICH were identified using the National Health Insurance Research Database of Taiwan. Neuroendoscopy and craniotomy groups comprised patients who underwent surgical treatment within 1 week, while those in the control group did not undergo early surgical treatment. Outcomes included subsequent hemorrhagic and ischemic stroke, following acute myocardial infarction, congestive heart failure, and mortality. After propensity score matching, there were 663 patients in each group. Compared to that in the control group, the neuroendoscopy and craniotomy groups had a significantly higher risk of secondary vascular events at 1 to 3 months of follow-up (adjusted HR, 2.08 and 1.95; 95% CI, 1.21-3.58 and 1.13-3.35; p < 0.01 and p < 0.05, respectively), but a significantly lower risk after 3 years of follow-up (adjusted HR, 0.52 and 0.52; 95% CI, 0.35-0.78 and 0.35-0.77; p < 0.01 and p < 0.01, respectively). The mortality rate was higher in the craniotomy group at 6 to 12 months of follow-up (adjusted HR, 2.18; 95% CI, 1.06-4.49; p < 0.05) compared to that in the control group. Thus, a timely surgical intervention for hematoma evacuation is advantageous in preventing secondary vascular events and improving outcomes in the long term. However, greater attention to secondary ischemic stroke following the initial sICH episode is needed.

BIO alleviates inflammation through inhibition of GSK-3β in a rat model of intracerebral hemorrhage

OBJECTIVE

Inflammation plays a key role in secondary brain damage following intracerebral hemorrhage (ICH). Glycogen synthase kinase-3β (GSK-3β) plays a strong proinflammatory role in many CNS diseases, including stroke. The present study was undertaken to examine the effects of 6-bromoindirubin-3'-oxime (BIO), a specific inhibitor of GSK-3β, on inflammation in ICH rats.

METHODS

An ICH rat model was induced by autologous whole-blood injection into the striatum. First, 10, 20, 40, 60, 80, or 100 μg/kg BIO was applied to ICH animals to determine an optimal dosage for producing sufficient GSK-3β inhibition in rat ipsilateral hippocampus by Western blotting. Second, 40 μg/kg BIO was applied to ICH rats for 1, 3, 7, or 14 days, respectively, to determine a suitable intervention time course of BIO by Western blotting analysis on GSK-3β. Third, Western blotting and enzyme-linked immunosorbent assay were used for quantification of inflammation-related factors upstream or downstream of GSK-3β in rat ipsilateral hippocampus. Then, immunohistochemical staining was applied to detect activated microglia and apoptotic cells in rat ipsilateral hippocampus. Last, neurobehavioral tests were performed to assess the sensorimotor impairments in the ICH rats.

RESULTS

The results show that BIO 1) blocked GSK-3βTyr216 phosphorylation/activation, thus stabilizing β-catenin, increasing upstream brain-derived neurotrophic factor and downstream heat shock protein 70 levels, and decreasing the levels of nuclear factor-κB p65 and cyclooxygenase 2; 2) decreased the levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin (IL)-1β and IL-6 and elevated the level of antiinflammatory cytokine IL-10; 3) inhibited microglia activation and cell apoptosis; and 4) improved the sensorimotor deficits of ICH rats.

CONCLUSIONS

BIO posttreatment inhibited microglia activation, prevented inflammation and hippocampal cell death, and ameliorated functional and morphological outcomes in a rat ICH model through inactivation of GSK-3β.

Protocatechuic acid exerts protective effects via suppression of the P38/JNK- NF-κB signalling pathway in an experimental mouse model of intracerebral haemorrhage

Protocatechuic acid (PCA) has been well studied for its neuroprotection value in several diseases, but the effect in intracerebral haemorrhage (ICH) has not been reported. Here we verified the protection of PCA in ICH, and investigated the relative mechanisms. ICH model mice were established by injection of collagenase IV. The mice were treated with PCA once per day for 3 days, starting immediately after operation. The modified neurological severity score (mNSS) of mice at 1st, 3rd and 7th day after operation were recorded. And some of mice were euthanized at 3rd day to compare brain water content, pro-inflammatory cytokines expression, and cell apoptosis in perihematomal tissue. Additionally, SH-SY5Y cells were treated hemin to mimic secondary injury of ICH. Cells were incubated with PCA for treatment. The cell viability, ROS, apoptosis rate and protein expression of apoptosis-relative protein and MAPKs and NF-κB were detected and analysed. The results revealed PCA alleviated the cerebral oedema at 3rd post ICH, and significantly improved neurological functions. PCA also attenuated the protein and gene expression of TNF-а, IL-1β and IL-6 vivo. PCA dose-dependently decreased the generation of ROS and apoptosis rate. Furthermore, PCA treatment dose-dependently decreased the expression of bax, cleaved caspase-3, increased bcl-2 expression; PCA downregulated P38/JNK-NF-κB pathway. In conclusion, PCA effectively improves prognosis of ICH mice by inhibiting oxidative stress, inflammation and apoptosis. The mechanism possibly results of downregulating of P38/JNK-NF-κB pathway, and PCA can be a potential therapeutic agent for ICH.

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.

Roles of Pericytes in Stroke Pathogenesis

Stroke is a cerebrovascular disorder that affects many people worldwide. In addition to the well-established functions of astrocytes and microglia in stroke pathogenesis, pericytes also play an important role in stroke progression and recovery. As perivascular multi-potent cells and an important component of the blood–brain barrier (BBB), pericytes have been shown to exert a large variety of functions, including serving as stem/progenitor cells and maintaining BBB integrity. Here in this review, we summarize the roles of pericytes in stroke pathogenesis, with a focus on their effects in cerebral blood flow, BBB integrity, angiogenesis, immune responses, scar formation and fibrosis.

Alternative activation-skewed microglia/macrophages promote hematoma resolution in experimental intracerebral hemorrhage

Microglia/macrophages (MMΦ) are highly plastic phagocytes that can promote both injury and repair in diseased brain through the distinct function of classically activated and alternatively activated subsets. The role of MMΦ polarization in intracerebral hemorrhage (ICH) is unknown. Herein, we comprehensively characterized MMΦ dynamics after ICH in mice and evaluated the relevance of MMΦ polarity to hematoma resolution. MMΦ accumulated within the hematoma territory until at least 14days after ICH induction. Microglia rapidly reacted to the hemorrhagic insult as early as 1-1.5h after ICH and specifically presented a "protective" alternatively activated phenotype. Substantial numbers of activated microglia and newly recruited monocytes also assumed an early alternatively activated phenotype, but the phenotype gradually shifted to a mixed spectrum over time. Ultimately, markers of MMΦ classic activation dominated at the chronic stage of ICH. We enhanced MMΦ alternative activation by administering intraperitoneal injections of rosiglitazone, and subsequently observed elevations in CD206 expression on brain-isolated CD11b⁺ cells and increases in IL-10 levels in serum and perihematomal tissue. Enhancement of MMΦ alternative activation correlated with hematoma volume reduction and improvement in neurologic deficits. Intraventricular injection of alternative activation signature cytokine IL-10 accelerated hematoma resolution, whereas microglial phagocytic ability was abolished by IL-10 receptor neutralization. Our results suggest that MMΦ respond dynamically to brain hemorrhage by exhibiting diverse phenotypic changes at different stages of ICH. Alternative activation-skewed MMΦ aid in hematoma resolution, and IL-10 signaling might contribute to regulation of MMΦ phagocytosis and hematoma clearance in ICH.

Miconazole protects blood vessels from MMP9-dependent rupture and hemorrhage

Hemorrhagic stroke accounts for 10-15% of all strokes and is strongly associated with mortality and morbidity worldwide, but its prevention and therapeutic interventions remain a major challenge. Here, we report the identification of miconazole as a hemorrhagic suppressor by a small-molecule screen in zebrafish. We found that a hypomorphic mutant fn40a, one of several known β-pix mutant alleles in zebrafish, had the major symptoms of brain hemorrhage, vessel rupture and inflammation as those in hemorrhagic stroke patients. A small-molecule screen with mutant embryos identified the anti-fungal drug miconazole as a potent hemorrhagic suppressor. Miconazole inhibited both brain hemorrhages in zebrafish and mesenteric hemorrhages in rats by decreasing matrix metalloproteinase 9 (MMP9)-dependent vessel rupture. Mechanistically, miconazole downregulated the levels of pErk and Mmp9 to protect vascular integrity in fn40a mutants. Therefore, our findings demonstrate that miconazole protects blood vessels from hemorrhages by downregulating the pERK-MMP9 axis from zebrafish to mammals and shed light on the potential of phenotype-based screens in zebrafish for the discovery of new drug candidates and chemical probes for hemorrhagic stroke.

Summary: A phenotype-based chemical screen in zebrafish identifies miconazole as a novel hemorrhagic suppressor. Miconazole inhibits vessel rupture and hemorrhages by decreasing pErk and MMP9 in zebrafish and rats.

OTUB1 attenuates neuronal apoptosis after intracerebral hemorrhage

OTUB1 is a member of deubiquitinating enzymes, which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. Previous studies have indicated that OTUB1 was expressed in brain. But its distribution and function in the brain remain unclear. In this study, we explored the roles of OTUB1 protein in the pathophysiology of intracerebral hemorrhage (ICH). From the results of Western blot, immunohistochemistry, and immunofluorescence, we found an obvious up-regulation of OTUB1 in neurons adjacent to the hematoma after ICH. Furthermore, we also found that the increase of OTUB1 expression was accompanied by the enhanced expression of Bax and active caspase-3, and decreased expression of Bcl-2 in the pathological process of rat ICH. What's more, our in vitro study, using OTUB1 RNA interference in PC12 cells, suggested that OTUB1 might exert its anti-apoptotic function in neuronal apoptosis. Therefore, OTUB1 may play a role in protecting the brain from secondary damage following ICH.

USP11, Deubiquitinating Enzyme, Associated with Neuronal Apoptosis Following Intracerebral Hemorrhage

Protein ubiquitination is a dynamic two-way process that can be reversed or regulated by deubiquitinating enzymes (DUB). USP11, located on the X chromosome, 6 is a member of USP subclass of the DUB family. Here, we demonstrate that USP11 may be involved in neuronal apoptosis in the processes of intracerebral hemorrhage (ICH). From the results of Western blot, immunohistochemistry, and immunofluorescence, we obtained a significant up-regulation of USP11 in neurons adjacent to the hematoma following ICH. Increasing USP11 level was found to be accompanied by the up-regulation of active caspase-3, Fas receptor (Fas), Fas ligand (FasL), and active caspase-8. Besides, USP11 co-localized well with active caspase-3 in neurons, indicating its potential role in neuronal apoptosis. What is more, knocking down USP11 by RNA-interference in PC12 cells reduced active caspase-3 expression. Thus, USP11 may play a role in promoting the brain secondary damage following ICH.