Soluble epoxide hydrolase inhibitor attenuates BBB disruption and neuroinflammation after intracerebral hemorrhage in mice.

Intracerebral hemorrhage (ICH) is a devastating disease with high mortality and morbidity. Soluble epoxide hydrolase (sEH) is the key enzyme in the epoxyeicosatrienoic acids (EETs) signaling. sEH inhibition has been demonstrated to have neuroprotective effects against multiple brain injuries. However, its role in the secondary injuries after ICH has not been fully elucidated. Here we tested the hypothesis that 1-Trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl)urea (TPPU), a potent and highly selective sEH inhibitor, suppresses inflammation and the secondary injuries after ICH. Adult male C57BL/6 mice were subjected to a collagenase-induced ICH model. TPPU alleviated blood-brain barrier damage, inhibited inflammatory response, increased M2 polarization of microglial cells, reduced the infiltration of peripheral neutrophils. In addition, TPPU attenuated neuronal injury and promoted functional recovery. The results suggest that sEH may represent a potential therapeutic target for the treatment of ICH.

Tyrosine kinase Fyn promotes apoptosis after intracerebral hemorrhage in rats by activating Drp1 signaling.

Tyrosine kinase Fyn is a member of the Src kinase family, which is involved in neuroinflammation, apoptosis, and oxidative stress. Its role in intracerebral hemorrhage (ICH) is not fully understood. In this study, we found that Fyn was significantly elevated in human brain tissue after ICH. Accordingly, we investigated the role of Fyn in a rat ICH model, which was constructed by injecting blood into the right basal ganglia. In this model, Fyn expression was significantly upregulated in brain tissue adjacent to the hematoma. SiRNA-induced Fyn knockdown was neuroprotective for secondary cerebral damage, as demonstrated by reduced brain edema, suppression of the modified neurological severity score, and mitigation of blood-brain barrier permeability and neuronal damage. Fyn downregulation reduced apoptosis following ICH, as indicated by downregulation of apoptosis-related proteins AIF, Cyt.c, caspase 3, and Bax; upregulation of anti-apoptosis-related protein Bcl-2; and decreased tunnel staining. Mdivi-1, a Drp1 inhibitor, reversed Fyn overexpression induced pro-apoptosis. However, Fyn did not significantly affect inflammation-related proteins NF-κB, TNF-α, caspase 1, MPO, IL-1ß, or IL-18 after ICH. Fyn activated Drp1 signaling by phosphorylating Drp1 at serine 616, which increased apoptosis after ICH in rats. This study clarifies the relationship between Fyn, apoptosis, and inflammation following ICH and provides a new strategy for exploring the prevention and treatment of ICH. KEY MESSAGES: ICH induced an increase in Fyn expression in human and rat cerebral tissues. Knockdown of Fyn prevented cerebral damage following ICH. Inhibition of Fyn had no significant effects on inflammatory responses. However, the downregulation of Fyn exerted neuroprotective effects on apoptosis. Fyn perturbed ICH-induced cell apoptosis by interacting with and phosphorylating (Ser616) Drp1 in a rat ICH model.

Thrombin-induced miRNA-24-1-5p upregulation promotes angiogenesis by targeting prolyl hydroxylase domain 1 in intracerebral hemorrhagic rats.

OBJECTIVE: Thrombin is a unique factor that triggers post-intracerebral hemorrhage (ICH) angiogenesis by increasing hypoxia-inducible factor-1α (HIF-1α) at the protein level. However, HIF-1α mRNA remains unchanged. MicroRNAs (miRNAs) mediate posttranscriptional regulation by suppressing protein translation from mRNAs. This study aimed to determine if miRNAs might be involved in thrombin-induced angiogenesis after ICH by targeting HIF-1α or its upstream prolyl hydroxylase domains (PHDs). METHODS: The study was divided into two parts. In part 1, rats received an injection of thrombin into the right globus pallidus. An miRNA array combined with miRNA target prediction, luciferase activity assay, and miRNA mimic/inhibitor transfection were used to identify candidate miRNAs and target genes. Part 2 included experiments 1 and 2. In experiment 1, rats were randomly divided into the sham group, ICH group, and ICH+hirudin-treated (thrombin inhibitor) group. In experiment 2, the rats were randomly divided into the sham group, ICH group, ICH+antagomir group, ICH+antagomir-control group, and ICH+vehicle group. Western blotting and quantitative real-time polymerase chain reaction were used to determine the expression of protein and miRNA, respectively. The coexpression of miR-24-1-5p (abbreviated to miR-24) and von Willebrand factor was detected by in situ hybridization and immunohistochemical analysis. The angiogenesis was evaluated by double-labeling immunofluorescence. Neurological function was evaluated by body weight, modified Neurological Severity Scores, and corner turn and foot-fault tests. RESULTS: In part 1, it was shown that miR-24, which is predicted to target PHD1, was upregulated (fold-change of 1.83) after thrombin infusion, and that the miR-24 mimic transfection decreased luciferase activity and downregulated PHD1 expression (p < 0.05). miR-24 inhibitor transfection increased PHD1 expression (p < 0.05). In part 2, it was shown that miR-24 was expressed in endothelial cells. The HIF-1α protein level and proliferating cell nuclear antigen-positive (PCNA+) nuclei in vessels were increased, while the PHD1 protein level was decreased after ICH, and these effects were reversed by hirudin (p < 0.05). The antagomiR-24-treated rats exhibited a markedly lower body weight and significantly poorer recovery from neurological deficit compared with those in ICH groups (p < 0.05). AntagomiR-24 intervention also led to lower miR-24 expression, a higher PHD1 protein level, and fewer PCNA+ nuclei in vessels compared with those in ICH groups (p < 0.05). CONCLUSIONS: The present study suggests that thrombin reduces HIF-1α degradation and initiates angiogenesis by increasing miR-24, which targets PHD1 after ICH.

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.

Role of p75 neurotrophin receptor in neuronal autophagy in intracerebral hemorrhage in rats through the mTOR signaling pathway.

Rupture of weakened blood vessels could lead to severe intracerebral hemorrhage (ICH) and brain injuries. This study was designed to explore the roles of p75 neurotrophin receptor (p75NTR) in neuronal autophagy in ICH rats. An ICH rat model was established, and then gain and loss of functions of p75NTR in rat tissues were performed. Then, the pathologic morphology, water content, and inflammation in brain tissues were assessed. Western blot analysis was applied to detect the levels of inflammatory proteins, apoptosis- and autophagy-related proteins, and the mammalian target of rapamycin (mTOR) pathway-related proteins. Neuronal autophagy was further measured with mTOR activated. In vitro experiments were also performed on brain microvascular endothelial cells (BMECs) and astrocytes. Consequently, we found p75NTR knockdown improved the pathologic morphology with reduced neuron damage, water content, permeability of blood-brain barrier and inflammation in ICH rat brain tissues. Besides, Knockdown of p75NTR decreased neuronal apoptosis and inactivated mTOR signaling pathway, but it elevated the levels of autophagy-related proteins. In vivo results were reproduced in in vitro experiments. This study demonstrated that knockdown of p75NTR could promote neuronal autophagy and reduce neuronal apoptosis via inactivating the mTOR pathway. We hope these findings could provide new therapeutic options for ICH treatment.

Serum lipoprotein-associated phospholipase A2 as a promising prognostic biomarker in association with 90-day outcome of acute intracerebral hemorrhage.

BACKGROUND: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is reflective of vascular inflammation and plays a role in the pathophysiology of cerebrovascular disease. We determine usefulness of serum Lp-PLA2 as a prognostic biomarker for intracerebral hemorrhage (ICH). METHODS: In this prospective, observational study, serum Lp-PLA2 concentrations were detected among 164 patients with acute spontaneous basal ganglia hemorrhage and 164 healthy controls. Using multivariate analysis, we analyzed its association with poor outcome (modified Rankin Scale >2) at poststroke 90 days and hemorrhagic severity indicated by National Institutes of Health Stroke Scale (NIHSS) score and hematoma volume. RESULTS: Serum Lp-PLA2 concentrations were remarkably higher in patients than in controls. Lp-PLA2 concentrations were independently correlated with NIHSS score (t = 5.095, P < .001) and hematoma volume (t = 2.850, P = .005). At 90-day follow-up, 85 patients (51.8%) had poor outcome. Under receiver operating characteristic curve, serum Lp-PLA2 showed a significant prognostic discriminatory capability (AUC, 0.813; 95% CI, 0.744-0.869). Serum Lp-PLA2 concentrations ≥304 ng/ml was an independent predictor associated with poor outcome (OR 7.052; 95% CI 1.971-25.228). CONCLUSIONS: Rising serum Lp-PLA2 concentrations are closely hemorrhagic severity and clinical outcomes after ICH, substantializing serum Lp-PLA2 as a potential prognostic biomarker of ICH.

Sex-specific Association of Matrix Metalloproteinases with Secondary Injury and Outcomes after Intracerebral Hemorrhage.

OBJECTIVE: Intracerebral hemorrhage affects approximately 2 million individuals per year. While the incidence is roughly equal in men and women, few studies have examined the influence of sex on secondary injury and associated long-term functional outcomes. Matrix metalloproteinases (MMPs) promote vessel rupture and worsen outcomes by potentiating blood-brain barrier breakdown after injury. We hypothesized that different MMP isoform levels would be predictive of injury severity, secondary injury, and long-term functional outcomes in males and females, respectively. METHODS: We examined the levels of MMP isoforms in serum samples from a prospective patient biobank (n = 55). Baseline clinical, radiographic, and laboratory data were also analyzed. RESULTS: We found that MMP-1 (P = .036), MMP-2 (P = .014), MMP-3 (P < .001), and MMP-9 (P = .02) levels gradually increased over time in male patients until 10 DPI. In female patients, we found a different pattern of activation: MMP-8 (P = .02) was the only isoform that significantly changed with time, which reached a peak at 3-5 days postinjury. Several MMP isoforms correlated with markers of secondary injury in female patients (all P < .05). Additionally, serum levels of MMP-3 (P = .011) in males and MMP-10 (P = .044) in females were significantly associated with long-term functional outcomes in a sex-specific manner. CONCLUSIONS: This is the first sex-specific study to examine serum MMP levels and their correlation with clinicoradiologic measures after intracerebral hemorrhage, and identifies potential biomarkers of secondary injury and long-term outcomes in both sexes.

Methylene blue offers neuroprotection after intracerebral hemorrhage in rats through the PI3K/Akt/GSK3ß signaling pathway.

Inflammation and apoptosis are two key factors contributing to secondary brain injury after intracerebral hemorrhage (ICH). In the present study, we explored the neuroprotective role of methylene blue (MB) in ICH rats and studied the potential mechanisms involved. Rats were subjected to local injection of collagenase IV in the striatum or sham surgery. We observed that MB treatment could exert a neuroprotective effect on ICH by promoting neurological scores, decreasing the brain water content, alleviating brain-blood barrier disruption, and improving the histological damages in the perihematomal areas. Furthermore, we demonstrated that the various mechanisms underlying MB's neuroprotective effects linked to inhibited apoptosis and inhibited neuroinflammation. In addition, wortmannin, a selective inhibitor of phosphoinositide 3-kinase (PI3K), could reverse the antiapoptotic and anti-inflammatory effects of MB, which suggested that the PI3K-Akt pathway played an important role. In conclusion, these data suggested that MB could inhibit apoptosis and ameliorate neuroinflammation after ICH, and its neuroprotective effects might be exerted via the activation of the PI3K/Akt/GSK3ß pathway.

Screening for Fabry Disease in Japanese Patients with Young-Onset Stroke by Measuring α-Galactosidase A and Globotriaosylsphingosine.

BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder caused by mutations in GLA, which encodes the enzyme α-galactosidase A (α-Gal A). Although the prevalence of Fabry disease in patients with stroke has been reported to range from 0% to 4%, few cohort studies have examined Japanese stroke patients. We aimed to clarify the prevalence of Fabry disease and the frequency of GLA mutations among patients with young-onset stroke in Japan. METHODS: From April 2015 to December 2016, we enrolled patients with young-onset (≤60 years old) ischemic stroke or intracerebral hemorrhage. We measured α-Gal A activity and the concentration of globotriaosylsphingosine in plasma. Genetic evaluations were performed in patients with low α-Gal A activity or high concentrations of globotriaosylsphingosine. RESULTS: Overall, 516 patients (median age of onset, 52 years old; 120 women) were consecutively enrolled in this study. Five patients (4 men and 1 woman) had low α-Gal A activity, and no patients were detected with the screen for plasma globotriaosylsphingosine levels. The genetic analysis did not identify a causative mutation responsible for classic Fabry disease in any of the patients, but 2 patients (.4%) carried the p.E66Q in GLA. CONCLUSIONS: No patient with Fabry disease was detected in our young-onset stroke cohort.

Glutathione peroxidase 4 participates in secondary brain injury through mediating ferroptosis in a rat model of intracerebral hemorrhage.

Oxidative stress plays an important role in secondary brain injury (SBI) after intracerebral hemorrhage (ICH), but the underling mechanism has not been fully elucidated. Recently, the antioxidant enzyme glutathione peroxidase 4 (GPX4), has attracted increasing attention due to its ability to degrade reactive oxygen species (ROS) which are the major indicator of oxidative stress; However, the role of GPX4 in ICH has not been reported. This study was designed to investigate the changes in protein levels, as well as potential role and mechanism of GPX4 in SBI following ICH using a Sprague-Dawley (SD) rat model of ICH induced by autologous blood injection into the right basal ganglia. Firstly, GPX4 protein levels in the brain were reduced gradually and bottomed out at 24 h after ICH, compared with the Sham group. Secondly, genetic-overexpression of GPX4 effectively increased level of GPX4 in the brain, and clearly relieved neuronal dysfunction, brain edema, blood brain barrier (BBB) injury, oxidative stress and inflammation after ICH. In contrast, inhibiting GPX4 with a specific pharmacological inhibitor or genetic knockdown exacerbated SBI after ICH. Finally, Ferrostatin-1, a chemical inhibitor of ferroptosis, was used to explore the role of ferroptosis in brain injury after ICH. The results suggest that inhibiting ferroptosis can significantly alleviate SBI after ICH. In summary, our work indicated that GPX4 contributes to SBI following ICH by mediating ferroptosis. Therefore, inhibiting ferroptosis with specific inhibitors or upregulation of GPX4 may be a potential strategy to ameliorate brain injury induced by ICH.

Lipopolysaccharide Induces Subacute Cerebral Microhemorrhages with Involvement of Nitric Oxide Synthase in Rats.

BACKGROUND: Cerebral microhemorrhage (CMH) is a neuropathological term that could be easily found in cerebral amyloid angiopathy, intracerebral hemorrhages, etc. CMHs could be detected clearly in vivo by magnetic resonance imaging (MRI)-susceptibility-weighted imaging or MRI T2* scan. This terminology is now accepted in the area of neuroimaging. CMHs are quite common in elderly patients and are associated with several other neuropsychiatric disorders. The causes of CMHs are complicated, and neuroinflammation is considered as one of the well-accepted mechanical factors. This study investigated whether lipopolysaccharide (LPS)-induced CMHs occur through the regulation of nitric oxide synthase (NOS) isoforms and reveals the exact underlying mechanism of LPS-induced CMHs. METHODS: Our work successfully developed a subacute model of CMHs in rats. LPS was intraperitoneally injected into rats at 0, 6, and 24 hours, which induced typical CMH features 7 days after the injection. These could be detected on the brain surface or parenchyma by hematoxylin and eosin staining and MRI. RESULTS: LPS-treated rats showed significant activation of astrocytes and microglia, as well as loss of pericytes and disruption of blood-brain barrier. Meanwhile, both astrocytes and microglia were positively correlated with CMH numbers. Furthermore, the expressions of NOS isoforms were also examined, and the levels of neuronal NOS and endothelial NOS were found to be elevated. CONCLUSIONS: These results implied that the NOS isoforms might be involved in the subacute model of CMHs in rats induced by LPS.

Genetic deletion or pharmacological inhibition of soluble epoxide hydrolase reduces brain damage and attenuates neuroinflammation after intracerebral hemorrhage.

BACKGROUND: Inflammatory responses significantly contribute to neuronal damage and poor functional outcomes following intracerebral hemorrhage (ICH). Soluble epoxide hydrolase (sEH) is known to induce neuroinflammatory responses via degradation of anti-inflammatory epoxyeicosatrienoic acids (EET), and sEH is upregulated in response to brain injury. The present study investigated the involvement of sEH in ICH-induced neuroinflammation, brain damage, and functional deficits using a mouse ICH model and microglial cultures. METHODS: ICH was induced by injecting collagenase in both wild-type (WT) C57BL/6 mice and sEH knockout (KO) mice. WT mice were injected intracerebroventricularly with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), a selective sEH inhibitor, 30 min before ICH. Expression of sEH in the hemorrhagic hemisphere was examined by immunofluorescence and Western blot analysis. The effects of genetic deletion or pharmacological inhibition of sEH by AUDA on neuroinflammatory responses, EET degradation, blood-brain barrier (BBB) permeability, histological damage, and functional deficits were evaluated. The anti-inflammatory mechanism of sEH inactivation was investigated in thrombin- or hemin-stimulated cultured microglia. RESULTS: ICH induced an increase in sEH protein levels in the hemorrhagic hemisphere from 3 h to 4 days. sEH was expressed in microglia/macrophages, astrocytes, neurons, and endothelial cells in the perihematomal region. Genetic deletion of sEH significantly attenuated microglia/macrophage activation and expression of inflammatory mediators and reduced EET degradation at 1 and 4 days post-ICH. Deletion of sEH also reduced BBB permeability, matrix metalloproteinase (MMP)-9 activity, neutrophil infiltration, and neuronal damage at 1 and 4 days. Likewise, administration of AUDA attenuated proinflammatory microglia/macrophage activation and EET degradation at 1 day post-ICH. These findings were associated with a reduction in functional deficits and brain damage for up to 28 days. AUDA also ameliorated neuronal death, BBB disruption, MMP-9 activity, and neutrophil infiltration at 1 day. However, neither gene deletion nor pharmacological inhibition of sEH altered the hemorrhage volume following ICH. In primary microglial cultures, genetic deletion or pharmacological inhibition of sEH by AUDA reduced thrombin- and hemin-induced microglial activation. Furthermore, AUDA reduced thrombin- and hemin-induced P38 MAPK and NF-κB activation in BV2 microglia cultures. Ultimately, AUDA attenuated N2A neuronal death that was induced by BV2 microglial conditioned media. CONCLUSIONS: Our results suggest that inhibition of sEH may provide a potential therapy for ICH by suppressing microglia/macrophage-mediated neuroinflammation.

Bosutinib Attenuates Inflammation via Inhibiting Salt-Inducible Kinases in Experimental Model of Intracerebral Hemorrhage on Mice.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage (ICH) is a subtype of stroke with highest mortality and morbidity. Pronounced inflammation plays a significant role in the development of the secondary brain injury after ICH. Recently, SIK-2 (salt-inducible kinase-2) was identified as an important component controlling inflammatory response. Here we sought to investigate the role of SIK-2 in post-ICH inflammation and potential protective effects of SIK-2 inhibition after ICH. METHODS: Two hundred and ninety-three male CD-1 mice were used. ICH was induced via injection of 30 µL of autologous blood. Recombinant SIK-2 was administrated 1 hour after ICH intracerebroventricularly. SIK-2 small interfering RNA was injected intracerebroventricularly 24 hours before ICH. Bosutinib, a clinically approved tyrosine kinase inhibitor with affinity to SIK-2, was given intranasally 1 hour or 6 hours after ICH. Effects of treatments were evaluated by neurological tests and brain water content calculation. Molecular pathways were investigated by Western blots and immunofluorescence studies. RESULTS: Endogenous SIK-2 was expressed in microglia and neurons. SIK-2 expression was reduced after ICH. Exogenous SIK-2 aggravated post-ICH inflammation, leading to brain edema and the neurobehavioral deficits. SIK-2 inhibition attenuated post-ICH inflammation, reducing brain edema and ameliorating neurological dysfunctions. Bosutinib inhibited SIK-2-attenuating ICH-induced brain damage. Protective effects of Bosutinib were mediated, at least partly, by CRTC3 (cyclic amp-response element binding protein-regulated transcription coactivator 3)/cyclic amp-response element binding protein/NF-κB (nuclear factor-κB) pathway. CONCLUSIONS: SIK-2 participates in inflammation induction after ICH. SIK-2 inhibition via Bosutinib or small interfering RNA decreased inflammation, attenuating brain injury. SIK-2 effects are, at least partly, mediated by CRTC3-cyclic amp-response element binding protein-NF-κB signaling pathway.

CM352 Reduces Brain Damage and Improves Functional Recovery in a Rat Model of Intracerebral Hemorrhage.

BACKGROUND: Intracerebral hemorrhage (ICH) is an acute neurological disorder with high mortality and no effective treatment. In addition to the initial bleeding event, rebleeding and hematoma expansion are associated with poor outcome in these patients. We studied the effectiveness of the new antifibrinolytic agent CM352, a short-half-life matrix metalloproteinase inhibitor, for achieving early hemostasis and improving functional recovery in a rat model of collagenase-induced ICH. METHODS AND RESULTS: ICH was induced by striatal injection of collagenase, and 1 hour later, rats received an intravenous injection of saline (n=6) or CM352 (1 mg/kg, n=6). Hematoma (basal and after 3 and 24 hours) and lesion (14 days) volumes were quantified on T2-weighted (T2) magnetic resonance images. Neurological and functional recovery was evaluated by using Bederson score and a cylinder test (basal, 24 hours, and 14 days). Early treatment (1 hour) with CM352 was efficient reducing hematoma expansion at 3 hours (P<0.01) and, more markedly, at 24 hours (P<0.01). Decreased bleeding after antifibrinolytic treatment was accompanied by reduced interleukin-6 levels at 3 hours (P<0.05) and smaller lesion volume at 14 days (P<0.01). CM352 drastically reduced sensorimotor impairment (cylinder test) after ICH in rats at 24 hours (P<0.01) and 14 days (P<0.01). Similarly, it also attenuated neurological deficit (Bederson scale) at 24 hours (P<0.01) and 14 days (P<0.01). Interestingly, late (3 hours) CM352 administration also resulted in reduced lesion size and better functional outcome. CONCLUSIONS: CM352, a new antifibrinolytic agent and matrix metalloproteinase inhibitor, effectively prevented hematoma growth and reduced lesion size in ICH in association with improved functional and neurological recovery.

Effects of phosphodiesterase 3A modulation on murine cerebral microhemorrhages.

BACKGROUND: Cerebral microbleeds (CMB) are MRI-demonstrable cerebral microhemorrhages (CMH) which commonly coexist with ischemic stroke. This creates a challenging therapeutic milieu, and a strategy that simultaneously protects the vessel wall and provides anti-thrombotic activity is an attractive potential approach. Phosphodiesterase 3A (PDE3A) inhibition is known to provide cerebral vessel wall protection combined with anti-thrombotic effects. As an initial step in the development of a therapy that simultaneously treats CMB and ischemic stroke, we hypothesized that inhibition of the PDE3A pathway is protective against CMH development. METHODS: The effect of PDE3A pathway inhibition was studied in the inflammation-induced and cerebral amyloid angiopathy (CAA)-associated mouse models of CMH. The PDE3A pathway was modulated using two approaches: genetic deletion of PDE3A and pharmacological inhibition of PDE3A by cilostazol. The effects of PDE3A pathway modulation on H&E- and Prussian blue (PB)-positive CMH development, BBB function (IgG, claudin-5, and fibrinogen), and neuroinflammation (ICAM-1, Iba-1, and GFAP) were investigated. RESULTS: Robust development of CMH in the inflammation-induced and CAA-associated spontaneous mouse models was observed. Inflammation-induced CMH were associated with markers of BBB dysfunction and inflammation, and CAA-associated spontaneous CMH were associated primarily with markers of neuroinflammation. Genetic deletion of the PDE3A gene did not alter BBB function, microglial activation, or CMH development, but significantly reduced endothelial and astrocyte activation in the inflammation-induced CMH mouse model. In the CAA-associated CMH mouse model, PDE3A modulation via pharmacological inhibition by cilostazol did not alter BBB function, neuroinflammation, or CMH development. CONCLUSIONS: Modulation of the PDE3A pathway, either by genetic deletion or pharmacological inhibition, does not alter CMH development in an inflammation-induced or in a CAA-associated mouse model of CMH. The role of microglial activation and BBB injury in CMH development warrants further investigation.

Significant elevation of serum caspase-3 levels in patients with intracerebral hemorrhage.

BACKGROUND: Caspase-3 is a potential marker of apoptosis. We investigated whether serum caspase-3 concentrations were increased and its association with severity and prognosis after intracerebral hemorrhage (ICH). METHODS: This prospective clinical study recruited 112 ICH patients and 112 healthy individuals. Serum was assayed for caspase-3 using enzyme-linked immunosorbent assay. Stroke severity was quantified by National Institute of Health Stroke Scale (NIHSS) and hematoma volume. Six-month outcome was measured by modified Rankin Scale. Analyses were performed using univariate and multivariate analyses. RESULTS: Patients had significantly higher serum caspase-3 concentrations than controls. Capase-3 concentrations correlated with NIHSS score and hematoma volume. Serum caspase-3 emerged as an independent predictor for 6-month mortality and bad prognosis (modified Rankin scale score>2). Based on receiver operating characteristic curve, caspase-3 concentrations showed similar prognostic value when compared with NIHSS score and hematoma volume. CONCLUSION: Serum caspase-3 concentrations are increased in ICH patients as well as correlate with clinical severity and prognosis.

Astrocyte heme oxygenase-1 reduces mortality and improves outcome after collagenase-induced intracerebral hemorrhage.

Pharmacotherapies that increase CNS expression of heme oxygenase-1 (HO-1) and other antioxidant proteins have improved outcome in experimental models of spontaneous intracerebral hemorrhage (ICH). In order to more specifically investigate the relationship between HO-1 and ICH outcome, mice expressing human HO-1 driven by the glial fibrillary acidic protein (GFAP) promoter (GFAP·HMOX1 mice) were tested in a model of in situ parenchymal hemorrhage. Injection of collagenase into the striata of wild-type (WT) mice resulted in a 26.3% mortality rate, with deaths equally distributed between males and females. Mortality was reduced to 4.48% in GFAP·HMOX1 mice. Cell viability in the injected striata of surviving WT mice was reduced by about half at one week and was significantly increased in transgenics; this benefit persisted over a 22day observation period. Cell counts guided by design-based stereology indicated loss of ~40% of neurons in WT hemorrhagic striata at one week, which was decreased by half in transgenics; no significant differences in microglia or astrocyte numbers were observed. Blood-brain barrier disruption and short-term neurological deficits were also mitigated in GFAP·HMOX1 mice, but long-term outcome did not differ from that of WT survivors. These results suggest that astrocyte HO-1 overexpression provides robust neuroprotection after acute intracerebral hemorrhage. Further investigation of drug or genetic therapies that selectively increase astrocyte HO-1 is warranted.

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 ß-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.

12/15-Lipoxygenase Inhibition or Knockout Reduces Warfarin-Associated Hemorrhagic Transformation After Experimental Stroke.

BACKGROUND AND PURPOSE: For stroke prevention, patients with atrial fibrillation typically receive oral anticoagulation. The commonly used anticoagulant warfarin increases the risk of hemorrhagic transformation (HT) when a stroke occurs; tissue-type plasminogen activator treatment is therefore restricted in these patients. This study was designed to test the hypothesis that 12/15-lipoxygenase (12/15-LOX) inhibition would reduce HT in warfarin-treated mice subjected to experimental stroke. METHODS: Warfarin was dosed orally in drinking water, and international normalized ratio values were determined using a Coaguchek device. C57BL6J mice or 12/15-LOX knockout mice were subjected to transient middle cerebral artery occlusion with 3 hours severe ischemia (model A) or 2 hours ischemia and tissue-type plasminogen activator infusion (model B), with or without the 12/15-LOX inhibitor ML351. Hemoglobin was determined in brain homogenates, and hemorrhage areas on the brain surface and in brain sections were measured. 12/15-LOX expression was detected by immunohistochemistry. RESULTS: Warfarin treatment resulted in reproducible increased international normalized ratio values and significant HT in both models. 12/15-LOX knockout mice suffered less HT after severe ischemia, and ML351 reduced HT in wild-type mice. When normalized to infarct size, ML351 still independently reduced hemorrhage. HT after tissue-type plasminogen activator was similarly reduced by ML351. CONCLUSIONS: In addition to its benefits in infarct size reduction, 12/15-LOX inhibition also may independently reduce HT in warfarin-treated mice. ML351 should be further evaluated as stroke treatment in anticoagulated patients suffering a stroke, either alone or in conjunction with tissue-type plasminogen activator.

The O-GlcNAc Modification of CDK5 Involved in Neuronal Apoptosis Following In Vitro Intracerebral Hemorrhage.

Contrary to cell cycle-associated cyclin-dependent kinases, CDK5 is best known for its regulation of signaling processes in regulating mammalian CNS development. Studies of CDK5 have focused on its phosphorylation, although the diversity of CDK5 functions in the brain suggests additional forms of regulation. Here we expanded on the functional roles of CDK5 glycosylation in neurons. We showed that CDK5 was dynamically modified with O-GlcNAc in response to neuronal activity and that glycosylation represses CDK5-dependent apoptosis by impairing its association with p53 pathway. Blocking glycosylation of CDK5 alters cellular function and increases neuronal apoptosis in the cell model of the ICH. Our findings demonstrated a new role for O-glycosylation in neuronal apoptosis and provided a mechanistic understanding of how glycosylation contributes to critical neuronal functions. Moreover, we identified a previously unknown mechanism for the regulation of activity-dependent gene expression, neural development, and apoptosis.