Soluble epoxide hydrolase inhibitor (TPPU) alleviates ferroptosis by regulating CCL5 after intracerebral hemorrhage in mice.

Soluble epoxide hydrolase (sEH) inhibition has been shown multiple beneficial effects against brain injuries of Intracerebral hemorrhage (ICH). However, the underlying mechanism of its neuroprotective effects after ICH has not been explained fully. Ferroptosis, a new form of iron-dependent programmed cell death, has been shown to be implicated in the secondary injuries after ICH. In this study, We examined whether sEH inhibition can alleviate brain injuries of ICH through inhibiting ferroptosis. Expression of several markers for ferroptosis was observed in the peri-hematomal brain tissues in mice after ICH. lip-1, a ferroptosis inhibitor, alleviated iron accumulation, lipid peroxidation and the secondary damages post-ICH in mice model. Intraperitoneal injection of 1-Trifluoromethoxyphenyl-3- (1-propionylpiperidin-4-yl)urea (TPPU), a highly selective sEH inhibitor, could inhibit ferroptosis and alleviate brain damages in ICH mice. Furthermore, RNA-sequencing was applied to explore the potential regulatory mechanism underlying the effects of TPPU in ferroptosis after ICH. C-C chemokine ligand 5 (CCL5) may be the key factor by which TPPU regulated ferroptosis after ICH since CCL5 antagonist could mimic the effects of TPPU and CCL5 reversed the inhibitive effect of TPPU on ferroptosis and the neuroprotective effects of TPPU on secondary damage after ICH. Taken together, these data indicate that ferroptosis is a key pathological feature of ICH and Soluble epoxide hydrolase inhibitor can exert neuroprotective effect by preventing ferroptosis after ICH.

[Genetic analysis of a case with Adult-onset globoid cell leukodystrophy].

OBJECTIVE: To explore the clinical features and genetic etiology of a patient with Adult-onset globoid cell leukodystrophy/Krabbe disease (KD). METHODS: A patient who was admitted to the Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology on February 15, 2022 due to exacerbation of right leg weakness for over 4 years was selected as the study subject. Clinical data and results of medical imaging and genetic analysis were analyzed. Candidate variants were verified by family analysis. RESULTS: The patient, a 36-year-old woman, had spasmodic gait as the primary presentation. Cranial magnetic resonance imaging (MRI) revealed symmetrical abnormalities in the bilateral corticospinal tracts, and the activity of ß-galactocerebrosidase (GALC) in her white blood cells was significantly decreased. The patient was found to harbor compound heterozygous variants of the GALC gene, namely c.461C>A (p.Pro154His) and c.1901T>C (p.Leu634Ser). Her mother, sister and nephew were heterozygous carriers of the c.461C>A (p.Pro154His) variant, whilst her father was heterozygous for the c.1901T>C (p.Leu634Ser) variant. CONCLUSION: The patient was ultimately diagnosed with adult-onset KD, for which the compound heterozygous variants of the GALC gene may be accountable.

Regulatory T cells alleviate myelin loss and cognitive dysfunction by regulating neuroinflammation and microglial pyroptosis via TLR4/MyD88/NF-κB pathway in LPC-induced demyelination.

Demyelination occurs in multiple central nervous system (CNS) disorders and is tightly associated with neuroinflammation. Pyroptosis is a form of pro-inflammatory and lytic cell death which has been observed in CNS diseases recently. Regulatory T cells (Tregs) have exhibited immunoregulatory and protective effects in CNS diseases. However, the roles of Tregs in pyroptosis and their involvement in LPC-induced demyelination have not been explicated. In our study, Foxp3-diphtheria toxin receptor (DTR) mice treated with diphtheria toxin (DT) or PBS were subjected to two-site lysophosphatidylcholine (LPC) injection. Immunofluorescence, western blot, Luxol fast blue (LFB) staining, quantitative real-time PCR (qRT-PCR) and neurobehavior assessments were performed to evaluate the severity of demyelination, neuroinflammation and pyroptosis. Pyroptosis inhibitor was further used to investigate the role of pyroptosis in LPC-induced demyelination. RNA-sequencing was applied to explore the potential regulatory mechanism underlying the involvement of Tregs in LPC-induced demyelination and pyroptosis. Our results showed that depletion of Tregs aggravated microgliosis, inflammatory responses, immune cells infiltration and led to exacerbated myelin injury as well as cognitive defects in LPC-induced demyelination. Microglial pyroptosis was observed after LPC-induced demyelination, which was aggravated by Tregs depletion. Inhibition of pyroptosis by VX765 reversed myelin injury and cognitive function exacerbated by Tregs depletion. RNA-sequencing showed TLR4/myeloid differentiation marker 88 (MyD88) as the central molecules in Tregs-pyroptosis pathway, and refraining TLR4/MyD88/NF-κB pathway alleviated the aggravated pyroptosis induced by Tregs depletion. In conclusion, our findings for the first time indicate that Tregs alleviate myelin loss and improve cognitive function by inhibiting pyroptosis in microglia via TLR4/MyD88/NF-κB pathway in LPC-induced demyelination.

Depletion of regulatory T cells exacerbates inflammatory responses after chronic cerebral hypoperfusion in mice.

Vascular cognitive impairment is the second most common cause of dementia which can be induced by chronic cerebral hypoperfusion. Regulatory T cells (Tregs) have been proven to provide beneficial effects in several central nervous system (CNS) diseases, but the roles of Tregs in chronic cerebral hypoperfusion-induced white matter damage have not been explored. In this study, Foxp3-diphtheria toxin receptor (DTR) mice treated with diphtheria toxin (DT) and wild type C57BL/6 mice treated with anti-CD25 antibody were subjected to bilateral carotid artery stenosis (BCAS). Flow cytometry analysis showed Tregs were widely distributed in spleen whereas barely distributed in brain under normal conditions. The distribution of lymphocytes and Tregs did not change significantly in spleen and brain after BCAS. Depletion of Tregs decreased the numbers of mature oligodendrocytes and anti-inflammatory microglia at 14 days and 28 days following BCAS. And pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and interferon-γ (IFN-γ) showed higher expression after Tregs depletion. In contrast, Tregs depletion did not change the overall severity of white matter injury as shown by the expression of myelin-associated glycoprotein (MAG), myelin basic protein (MBP), luxol fast blue (LFB) staining and electron microscopy assay. Moreover, Tregs depletion had marginal effect on cognition defects after BCAS revealed by Morris water maze and novel object recognition examination at 28 days after BCAS. In summary, our results suggest an anti-inflammatory role of Tregs with marginal effects on white matter damage in mice after BCAS-induced chronic cerebral hypoperfusion.

Risk Prediction Models for Early ICU Admission in Patients With Autoimmune Encephalitis: Integrating Scale-Based Assessments of the Disease Severity.

Background: In patients with autoimmune encephalitis (AE), the prediction of progression to a critically ill status is challenging but essential. However, there is currently no standard prediction model that comprehensively integrates the disease severity and other clinical features. The clinical assessment scale in autoimmune encephalitis (CASE) and the modified Rankin Scale (mRS) have both been applied for evaluating the severity of AE. Here, by combining the two scales and other clinical characteristics, we aimed to investigate risk factors and construct prediction models for early critical care needs of AE patients. Methods: Definite and probable AE patients who were admitted to the neurology department of Tongji Hospital between 2013 and 2021 were consecutively enrolled. The CASE and mRS scores were used to evaluate the overall symptom severity at the time of hospital admission. Using logistic regression analysis, we analyzed the association between the total scores of the two scales and critical illness individually and then we evaluated this association in combination with other clinical features to predict early intensive care unit (ICU) admission. Finally, we constructed four prediction models and compared their performances. Results: Of 234 patients enrolled, forty developed critical illness and were early admitted to the ICU (within 14 days of hospitalization). Four prediction models were generated; the models were named CASE, CASE-plus (CASE + prodromal symptoms + elevated fasting blood glucose + elevated cerebrospinal fluid (CSF) white blood cell (WBC) count), mRS and mRS-plus (mRS + prodromal symptoms + abnormal EEG results + elevated fasting blood glucose + elevated CSF WBC count) and had areas under the ROC curve of 0.850, 0.897, 0.695 and 0.833, respectively. All four models had good calibrations. In general, the models containing "CASE" performed better than those including "mRS", and the CASE-plus model demonstrated the best performance. Conclusion: Overall, the symptom severity at hospital admission, as defined by CASE or mRS, could predict early ICU admission, especially when assessed by CASE. Adding other clinical findings, such as prodromal symptoms, an increased fasting blood glucose level and an increased CSF WBC count, could improve the predictive efficacy.

Caspase-1: A Promising Target for Preserving Blood-Brain Barrier Integrity in Acute Stroke.

The blood-brain barrier (BBB) acts as a physical and biochemical barrier that plays a fundamental role in regulating the blood-to-brain influx of endogenous and exogenous components and maintaining the homeostatic microenvironment of the central nervous system (CNS). Acute stroke leads to BBB disruption, blood substances extravasation into the brain parenchyma, and the consequence of brain edema formation with neurological impairment afterward. Caspase-1, one of the evolutionary conserved families of cysteine proteases, which is upregulated in acute stroke, mainly mediates pyroptosis and compromises BBB integrity via lytic cellular death and inflammatory cytokines release. Nowadays, targeting caspase-1 has been proven to be effective in decreasing the occurrence of hemorrhagic transformation (HT) and in attenuating brain edema and secondary damages during acute stroke. However, the underlying interactions among caspase-1, BBB, and stroke still remain ill-defined. Hence, in this review, we are concerned about the roles of caspase-1 activation and its associated mechanisms in stroke-induced BBB damage, aiming at providing insights into the significance of caspase-1 inhibition on stroke treatment in the near future.

The Two-Pore Domain Potassium Channel TREK-1 Promotes Blood-Brain Barrier Breakdown and Exacerbates Neuronal Death After Focal Cerebral Ischemia in Mice.

Earlier studies have shown the neuroprotective role of TWIK-related K+ channel 1 (TREK-1) in global cerebral and spinal cord ischemia, while its function in focal cerebral ischemia has long been debated. This study used TREK-1-deficient mice to directly investigate the role of TREK-1 after focal cerebral ischemia. First, immunofluorescence assays in the mouse cerebral cortex indicated that TREK-1 expression was mostly abundant in astrocytes, neurons, and oligodendrocyte precursor cells but was low in myelinating oligodendrocytes, microglia, or endothelial cells. TREK-1 deficiency did not affect brain weight and morphology or the number of neurons, astrocytes, or microglia but did increase glial fibrillary acidic protein (GFAP) expression in astrocytes of the cerebral cortex. The anatomy of the major cerebral vasculature, number and structure of brain micro blood vessels, and blood-brain barrier integrity were unaltered. Next, mice underwent 60 min of focal cerebral ischemia and 72 h of reperfusion induced by the intraluminal suture method. TREK-1-deficient mice showed less neuronal death, smaller infarction size, milder blood-brain barrier (BBB) breakdown, reduced immune cell invasion, and better neurological function. Finally, the specific pharmacological inhibition of TREK-1 also decreased infarction size and improved neurological function. These results demonstrated that TREK-1 might play a detrimental rather than beneficial role in focal cerebral ischemia, and inhibition of TREK-1 would be a strategy to treat ischemic stroke in the clinic.

Persistent pain and numbness in the extremities of an adult due to paraneoplastic peripheral neuropathy caused by olfactory neuroblastoma: A case report.

Background: Paraneoplastic peripheral neuropathy (PPN) caused by olfactory neuroblastoma (ONB) has not yet been reported. Case report: We present a rare case of an adult who hospitalized repeatedly over the past 9 months for persistent pain and numbness in the limbs. This patient was initially diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP) and treated accordingly, but neurological symptoms did not improve significantly. After this admission, FDG-PET/CT showed focal hypermetabolism of a soft-tissue mass in the nasal cavity, and further lesion biopsy suggested ONB. Combined with positive serum anti-Hu antibody, the diagnosis of PPN associated with ONB was eventually made. Furthermore, the patient's neurological symptoms were relieved after removal of the primary tumor, confirming the accuracy of the diagnosis. Conclusion: Our case not only expanded the clinical characteristics of ONB but also highlighted the importance of early and comprehensive tumor screening for the diagnosis of PPN.

Predicting the occurrence of early seizures after cerebral venous thrombosis using a comprehensive nomogram.

BACKGROUND: Seizure is a common clinical manifestation of cerebral venous thrombosis (CVT). The mortality rate of patients with CVT with seizure is three times higher than that of patients without seizure. The aim of this study was to develop a nomogram to predict the individual probability of acute seizure events in patients with CVT. METHOD: This was a single-center, retrospective cohort study. We analyzed and compared demographic variables, epidemiological risk factors, clinical presentation, laboratory results and imaging data in a cohort of 142 patients who were diagnosed with CVT in our hospital from January 2013 to December 2018. A nomogram was constructed to predict the risk of early seizure (ES) in these patients according to the multivariable logistic regression analysis results. The concordance index, GiViTi calibration belt and decision curve analysis (DCA) were used to assess nomogram performance. RESULTS: Forty-three (30.28%) patients experienced seizure within 2 weeks after a CVT diagnosis. Multivariate analysis identified focal neurologic deficit, Glasgow Coma Scale (GCS) scores ≤ 8 on admission, hemorrhagic lesions, superior sagittal sinus thrombosis (SSST) and frontal lobe lesions as independent predictive factors for ES occurrence after CVT. A nomogram was generated based on these predictive factors with the concordance index reaching 0.82, indicating that the clinical tool was well calibrated. DCA showed that the model was useful with a threshold probability in the range of 0-77%. CONCLUSIONS: We developed the first nomogram that could predict the risk of ES in CVT patients. This effective and convenient tool has shown promising clinical benefit and will assist clinicians in making treatment decisions.

Long QT syndrome with potassium voltage-gated channel subfamily H member 2 gene mutation mimicking refractory epilepsy: case report.

BACKGROUND: Epileptic seizures can be difficult to distinguish from other etiologies that cause cerebral hypoxia, especially cardiac diseases. Long QT syndrome (LQTS), especially LQTS type 2 (LQT2), frequently masquerades as seizures because of the transient cerebral hypoxia caused by ventricular arrhythmia. The high rate of sudden death in LQTS highlights the importance of accurate and early diagnosis; correct diagnosis of LQTS also prevents inappropriate treatment with anti-epileptic drugs (AEDs). CASE PRESENTATION: We report a case of congenital LQT2 with potassium voltage-gated channel subfamily H member 2 gene (KCNH2) mutation misdiagnosed as refractory epilepsy and treated with various AEDs for 22 years. The possibility of cardiac arrhythmia was suspected after the patient presented to the emergency room and the electrocardiograph (ECG) monitor showed paroxysmal ventricular tachycardia during attacks. Atypical seizure like attacks with prodromal uncomfortable chest sensation and palpitation, triggered by auditory stimulation, and typical ventricular tachycardia monitored by ECG raised suspicion for LQT2, which was confirmed by exome sequencing and epileptic seizure was ruled out by 24-h EEG monitoring. Although the patient rejected implantation of an implantable cardioverter defibrillator, ß blocker was given and the syncope only attacked 1-2 per year when there was an incentive during the 5 years follow up. CONCLUSIONS: Our case illustrates how long LQTS can masquerade convincingly as epilepsy and can be treated wrongly with AEDs, putting the patient at high risk of sudden cardiac death. Careful ECG evaluation is recommend for both patients with first seizure and those with refractory epilepsy.

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.

Tamoxifen promotes white matter recovery and cognitive functions in male mice after chronic hypoperfusion.

Cerebral white matter lesions (WMLs) induced by chronic cerebral hypoperfusion are one of the major components of stroke pathology and closely associated with cognitive impairment. However, the repair and related pathophysiology of white matter after brain injury remains relatively elusive and underexplored. Successful neuroregeneration is a method for the potential treatment of central nervous system (CNS) disorders. A non-steroidal estrogen receptor modulator, Tamoxifen, is an effective inhibitor of cell-swelling-activated anion channels and can mimic neuroprotective effects of estrogen in experimental ischemic stroke. However, its remains unclear whether Tamoxifen has beneficial effects in the pathological process after WMLs. In the present study, we investigated the efficacy of Tamoxifen on multiple elements of oligovascular niche of the male C57BL/6 mice brain after bilateral carotid artery stenosis (BCAS) - induced WMLs. Tamoxifen was injected intraperitoneally once daily from 1 day after BCAS until 1 day before sacrificed. Following chronic hypoperfusion, BCAS mice presented white matter demyelination, loss of axon-glia integrity, activated inflammatory response, and cognitive impairments. Tamoxifen treatment significantly facilitated functional restoration of working memory impairment in mice after white matter injury, thus indicating a translational potential for this estrogen receptor modulator given its clinical safety and applicability for WMLs, which lack of currently available treatments. Furthermore, Tamoxifen treatment reduced microglia activation and inflammatory response, favored microglial polarization toward to the M2 phenotype, enhanced oligodendrocyte precursor cells proliferation and differentiation, and promoted remyelination after chronic hypoperfusion. Together, our data indicate that Tamoxifen could alleviate white matter injury and play multiple targets protective effects following chronic hypoperfusion, which is a promising candidate for the therapeutic target for ischemic WMLs and other demyelination diseases associated cognitive impairment.

Deficiency of TREK-1 potassium channel exacerbates blood-brain barrier damage and neuroinflammation after intracerebral hemorrhage in mice.

BACKGROUND: Intracerebral hemorrhage (ICH) is a devastating medical emergency with high mortality and severe neurological deficit. ICH-related poor outcomes are due to a combination of pathological processes that could be complicated by secondary insults. TWIK-related K+ channel 1 (TREK-1) is a two-pore-domain potassium channel that is highly expressed in the mammalian nervous system. Previous studies have shown that TREK-1 channels play important roles in various central nervous system diseases. However, its role in the secondary injuries after intracerebral hemorrhage remains unknown. In this study, we explored the function of TREK-1 in secondary blood-brain barrier injuries and neuroinflammation after intracerebral hemorrhage in mice. METHODS: Adult male TREK-1-/- mice and WT mice were subjected to a collagenase-induced ICH model. Immunostaining, western blot, and enzyme-linked immunosorbent assay were used to assess inflammatory infiltration and neuronal death. Blood-brain barrier compromise was assessed using electron microscopy and Evans Blue dye injection on days 1 and 3 after intracerebral hemorrhage. Magnetic resonance imaging and behavioral assessments were conducted to evaluate the neurologic damage and recovery after intracerebral hemorrhage. RESULTS: Genetic deficiency of TREK-1 channel exacerbated blood-brain barrier impairment and promoted cerebral edema after intracerebral hemorrhage. Meanwhile, TREK-1 deficiency aggravated focal inflammatory featured by the increased recruitment of microglia and neutrophils, the enhanced secretion of proinflammatory factors interleukin-1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), and cell adhesion molecules (CAMs). Furthermore, TREK-1 deficiency promoted neuronal injury and neurological impairment. CONCLUSIONS: These results establish the first in vivo evidence for the protective role of TREK-1 in blood-brain barrier injury and neuroinflammation after intracerebral hemorrhage. TREK-1 may thereby be harnessed to a potential therapeutical target for the treatment of intracerebral hemorrhage.

Inhibition of Astrocyte Connexin 43 Channels Facilitates the Differentiation of Oligodendrocyte Precursor Cells Under Hypoxic Conditions In Vitro.

Oligodendrocyte precursor cells (OPCs) proliferation and differentiation are essential for remyelination after white matter injury. Astrocytes could promote oligodendrogenesis after white matter damage whereas the underlying mechanisms are unknown. In this study, the role of astrocytic connexin43 (Cx43) hemichannels involved in OPC proliferation and differentiation in chronic hypoxia was evaluated. In an astrocyte-OPC co-culture chronic hypoxia model, OPCs became proliferative but failed to mature into oligodendrocytes. Application of astrocytic Cx43 blockers attenuated astrocyte activation, suppressed Cx43 hemichannel uptake activity and glutamate release induced by hypoxia, as well as improved OPC differentiation. Moreover, AMPA but not NMDA glutamate receptor antagonist rescued OPC differentiation in hypoxia. In conclusion, these findings suggested that astrocytic Cx43 hemichannel inhibition could potentially improve OPC maturation by attenuating AMPAR-mediated glutamate signaling. Astrocytic Cx43 hemichannels could serve as a potential therapeutic target for remyelination after chronic hypoxia.

Soluble epoxide hydrolase inhibition Promotes White Matter Integrity and Long-Term Functional Recovery after chronic hypoperfusion in mice.

Chronic cerebral hypoperfusion induced cerebrovascular white matter lesions (WMLs) are closely associated with cognitive impairment and other neurological deficits. The mechanism of demyelination in response to hypoperfusion has not yet been fully clarified. Soluble epoxide hydrolase (sEH) is an endogenous key enzyme in the metabolic conversion and degradation of P450 eicosanoids called epoxyeicosatrienoic acids. Inhibition of sEH has been suggested to represent a prototype "combination therapy" targeting multiple mechanisms of stroke injury with a single agent. However, its role in the pathological process after WMLs has not been clarified. The present study was to investigate the role of a potent sEH inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), on multiple elements in white matter of mice brain after chronic hypoperfusion. Adult male C57BL/6 mice were subjected to bilateral carotid artery stenosis (BCAS) to induce WMLs. Administration of TPPU significantly inhibited microglia activation and inflammatory response, increased M2 polarization of microglial cells, enhanced oligodendrogenesis and differentiation of oligodendrocytes, promoted white matter integrity and remyelination following chronic hypoperfusion. Moreover, these cellular changes were translated into a remarkable functional restoration. The results suggest that sEH inhibition could exert multi-target protective effects and alleviate cognitive impairment after chronic hypoperfusion induced WMLs in mice.

Deficiency of TREK-1 potassium channel exacerbates secondary injury following spinal cord injury in mice.

Spinal cord injury (SCI) involves complex pathological process which can be complicated by secondary injury. TREK-1 is a member of the two-pore domain potassium (K2P) channel family, which can be modulated by a number of physiological and pathological stimuli. Recent studies suggest that TREK-1 plays an active role in depression, pain and neuroprotection. However, its role in the pathological process after SCI remains unclear. In this study, we tested the expression and function of TREK-1 in spinal cord of mice after traumatic SCI. TREK-1 was widely expressed in mice spinal cord, including astrocytes and neurons. Deficiency of TREK-1 significantly exacerbated focal inflammatory responses as indicated by the increased accumulation of microglia/macrophage as well as pro-inflammatory factor interleukin-1 beta (IL-1ß) and tumor necrosis factor alpha expression. Meanwhile, TREK-1 knockout mice showed enhanced reactive astrogliosis, chondroitin sulphate proteoglycans (CSPGs) production and decreased glutamate transporter-1 expression compared to the wide-type mice after SCI. Furthermore, TREK-1 deficiency promoted neurons and oligodendrocytes apoptosis, aggravated demyelination, cavity formation and retarded motor recovery. In summary, our findings provide the first in vivo evidence suggesting that TREK-1 may thereby constitute a promising therapeutic target to treat acute SCI.

Soluble epoxide hydrolase inhibition provides multi-target therapeutic effects in rats after spinal cord injury.

Multiple players are involved in motor and sensory dysfunctions after spinal cord injury (SCI). Therefore, therapeutic approaches targeting these various players in the damage cascade hold considerable promise for the treatment of traumatic spinal cord injury. Soluble epoxide hydrolase (sEH) is an endogenous key enzyme in the metabolic conversion and degradation of P450 eicosanoids called epoxyeicosatrienoic acids (EETs). sEH inhibition has been shown to provide neuroprotective effects upon multiple elements of neurovascular unit under cerebral ischemia. However, its role in the pathological process after SCI remains unclear. In this study, we tested the hypothesis that sEH inhibition may have therapeutic effects in preventing secondary damage in rats after traumatic SCI. sEH was widely expressed in spinal cord tissue, mainly confined to astrocytes, and neurons. Administration of sEH inhibitor AUDA significantly suppressed local inflammatory responses as indicated by the reduced microglia activation and IL-1 ß expression, as well as the decreased infiltration of neutrophils and T lymphocytes. Meanwhile, reactive astrogliosis was remarkably attenuated. Furthermore, treatment of AUDA improved angiogenesis, inhibited neuron cells apoptosis, alleviated demyelination and formation of cavity and improved motor recovery. Together, these results provide the first in vivo evidence that sEH inhibition could exert multiple targets protective effects after SCI in rats. sEH may thereby serve as a promising multi-mechanism therapeutic target for the treatment of SCI.

Epoxyeicosanoid Signaling Provides Multi-target Protective Effects on Neurovascular Unit in Rats After Focal Ischemia.

Multiple players are involved in the highly complex pathophysiologic responses after stroke. Therefore, therapeutic approaches that target multiple cellular elements of the neurovascular unit in the damage cascade hold considerable promise for the treatment of stroke. Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid to biologically active eicosanoids called epoxyeicosatrienoic acids (EETs), which are further converted by soluble epoxide hydrolase (sEH) to less bioactive diols. EETs have been shown to exert direct cytoprotective effects upon several individual components of the neurovascular unit under simulated ischemic conditions in vitro. However, the cellular mechanism underlying EET-mediated neuroprotective effects after ischemia remains to be clarified. In this study, we investigated the effects of 14,15-EET and 12-(3-adamantan-1-yl-ureido)dodecanoic acid (AUDA), a selective inhibitor of sEH, on multiple elements of neurovascular unit of the rat brain after middle cerebral artery occlusion-induced focal ischemia. The results showed that exogenous administration of 14,15-EET or AUDA could suppress astrogliosis and glial scar formation, inhibit microglia activation and inflammatory response, promote angiogenesis, attenuate neuronal apoptosis and infarct volume, and further promote the behavioral function recovery after focal ischemia. The results suggest that epoxyeicosanoid signaling is a promising multi-mechanism therapeutic target for the treatment of stroke.