Extracellular cold-inducible RNA-binding protein mediated neuroinflammation and neuronal apoptosis after traumatic brain injury.

Background: Extracellular cold-inducible RNA-binding protein (eCIRP) plays a vital role in the inflammatory response during cerebral ischaemia. However, the potential role and regulatory mechanism of eCIRP in traumatic brain injury (TBI) remain unclear. Here, we explored the effect of eCIRP on the development of TBI using a neural-specific CIRP knockout (KO) mouse model to determine the contribution of eCIRP to TBI-induced neuronal injury and to discover novel therapeutic targets for TBI. Methods: TBI animal models were generated in mice using the fluid percussion injury method. Microglia or neuron lines were subjected to different drug interventions. Histological and functional changes were observed by immunofluorescence and neurobehavioural testing. Apoptosis was examined by a TdT-mediated dUTP nick end labelling assay in vivo or by an annexin-V assay in vitro. Ultrastructural alterations in the cells were examined via electron microscopy. Tissue acetylation alterations were identified by non-labelled quantitative acetylation via proteomics. Protein or mRNA expression in cells and tissues was determined by western blot analysis or real-time quantitative polymerase chain reaction. The levels of inflammatory cytokines and mediators in the serum and supernatants were measured via enzyme-linked immunoassay. Results: There were closely positive correlations between eCIRP and inflammatory mediators, and between eCIRP and TBI markers in human and mouse serum. Neural-specific eCIRP KO decreased hemispheric volume loss and neuronal apoptosis and alleviated glial cell activation and neurological function damage after TBI. In contrast, eCIRP treatment resulted in endoplasmic reticulum disruption and ER stress (ERS)-related death of neurons and enhanced inflammatory mediators by glial cells. Mechanistically, we noted that eCIRP-induced neural apoptosis was associated with the activation of the protein kinase RNA-like ER kinase-activating transcription factor 4 (ATF4)-C/EBP homologous protein signalling pathway, and that eCIRP-induced microglial inflammation was associated with histone H3 acetylation and the α7 nicotinic acetylcholine receptor. Conclusions: These results suggest that TBI obviously enhances the secretion of eCIRP, thereby resulting in neural damage and inflammation in TBI. eCIRP may be a biomarker of TBI that can mediate the apoptosis of neuronal cells through the ERS apoptotic pathway and regulate the inflammatory response of microglia via histone modification.

Neuroimmune Regulation in Sepsis-Associated Encephalopathy: The Interaction Between the Brain and Peripheral Immunity.

Sepsis-associated encephalopathy (SAE), the most popular cause of coma in the intensive care unit (ICU), is the diffuse cerebral damage caused by the septic challenge. SAE is closely related to high mortality and extended cognitive impairment in patients in septic shock. At present, many studies have demonstrated that SAE might be mainly associated with blood-brain barrier damage, abnormal neurotransmitter secretion, oxidative stress, and neuroimmune dysfunction. Nevertheless, the precise mechanism which initiates SAE and contributes to the long-term cognitive impairment remains largely unknown. Recently, a growing body of evidence has indicated that there is close crosstalk between SAE and peripheral immunity. The excessive migration of peripheral immune cells to the brain, the activation of glia, and resulting dysfunction of the central immune system are the main causes of septic nerve damage. This study reviews the update on the pathogenesis of septic encephalopathy, focusing on the over-activation of immune cells in the central nervous system (CNS) and the "neurocentral-endocrine-immune" networks in the development of SAE, aiming to further understand the potential mechanism of SAE and provide new targets for diagnosis and management of septic complications.

Adult sacrococcygeal teratoma: a retrospective study over eight years at a single institution.

OBJECTIVE: To determine the clinical, imaging, and histological features, and surgical resection modalities and outcomes of adult sacrococcygeal teratoma (SCT). METHODS: Adult patients with histopathologically diagnosed SCT were enrolled in our hospital between August 2010 and August 2018. Each patient's characteristics and clinical information were reviewed. RESULTS: There were 8 patients in the study (2 males, 6 females) with a median age of 34 years (range, 18-67 years). The time to clinical symptoms was 14 d to 35 years, with a median time of 4 years. Six patients presented with symptoms of sacrococcygeal pain, and four with signs of sacrococcygeal mass and ulceration in the sacrococcygeal region. Six patients were evaluated using a combination of computed tomography (CT) and magnetic resonance imaging (MRI). All patients showed a presacral tumor with heterogeneous intensity on CT images. All patients underwent surgical treatment, including 6 parasacral, 1 transabdominal, and 1 combined anterior-posterior surgery cases. Seven patients were histopathologically diagnosed with benign mature SCT, and have shown no recurrence. One patient had malignant SCT, with recurrence at 84 months after surgery. After a second surgery, the patient had no recurrence within 6 months follow-up after re-resection. CONCLUSIONS: Our retrospective study demonstrated: (1) adult SCT is difficult to diagnose because of a lack of typical clinical symptoms and signs; (2) a combination of CT and MRI examination is beneficial for preoperative diagnosis; (3) the choice of surgical approach and surgical resection modality depends on the size, location, and components of the tumor, which can be defined from preoperative CT and MRI evaluation; (4) most adult SCTs are benign; the surgical outcome for the malignant SCT patient was good after complete resection. Even for the patient with recurrent malignant SCT, the surgical outcome was good after re-resection.

Peroxiredoxin 1/2 protects brain against H2O2-induced apoptosis after subarachnoid hemorrhage.

Recent studies suggest that peroxiredoxin1/2 (Prx1/2) may be involved in the pathophysiology of postischemic inflammatory responses in the brain. In this study, we assessed the distribution and function of Prx1/2 in mice after experimental subarachnoid hemorrhage (SAH). We investigated the distribution of Prx1/2 in the brains of mice both in vivo and in vitro using immunofluorescence staining. The expression of Prx1/2 after SAH was determined by Western blot. Adenanthin was used to inhibit Prx1/2 function, and Prx1/2 overexpression was achieved by injecting adeno-associated virus. Oxidative stress and neuronal apoptosis were assessed both in vivo and in vitro. The neurologic function, inflammatory response, and related cellular signals were analyzed. The results showed that Prx1 was mainly expressed in astrocytes, and Prx2 was abundant in neurons. The expression of Prx1/2 was elevated after SAH, and their expression levels peaked before proinflammatory cytokines. Inhibiting Prx1/2 promoted neuronal apoptosis by increasing the hydrogen peroxide (H2O2) levels via the apoptosis signal-regulating kinase 1/p38 pathway. By contrast, overexpression of Prx1/2 attenuated oxidative stress and neuronal apoptosis after SAH. Thus, early expression of Prx1/2 may protect the brain from oxidative damage after SAH and may provide a novel target for treating SAH.-Lu, Y., Zhang, X.-S., Zhou, X.-M., Gao, Y.-Y., Chen, C.-L., Liu, J.-P., Ye, Z.-N., Zhang, Z.-H., Wu, L.-Y., Li, W., Hang, C.-H. Peroxiredoxin 1/2 protects brain against H2O2-induced apoptosis after subarachnoid hemorrhage.

Biochanin A Reduces Inflammatory Injury and Neuronal Apoptosis following Subarachnoid Hemorrhage via Suppression of the TLRs/TIRAP/MyD88/NF-κB Pathway.

Inflammatory injury and neuronal apoptosis participate in the period of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Suppression of inflammation has recently been shown to reduce neuronal death and neurobehavioral dysfunction post SAH. Biochanin A (BCA), a natural bioactive isoflavonoid, has been confirmed to emerge the anti-inflammatory pharmacological function. This original study was aimed at evaluating and identifying the neuroprotective role of BCA and the underlying molecular mechanism in an experimental Sprague-Dawley rat SAH model. Neurobehavioral function was evaluated via the modified water maze test and modified Garcia neurologic score system. Thus, we confirmed that BCA markedly decreased the activated level of TLRs/TIRAP/MyD88/NF-κB pathway and the production of cytokines. BCA also significantly ameliorated neuronal apoptosis which correlated with the improvement of neurobehavioral dysfunction post SAH. These results indicated that BCA may provide neuroprotection against EBI through the inhibition of inflammatory injury and neuronal apoptosis partially via the TLRs/TIRAP/MyD88/NF-κB signal pathway.

The rise of soluble platelet-derived growth factor receptor ß in CSF early after subarachnoid hemorrhage correlates with cerebral vasospasm.

Platelet-derived growth factor ß (PDGFß) has been proposed to contribute to the development of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH), and soluble PDGFRß (sPDGFRß) is considered to be an inhibitor of PDGF signaling. We aimed at determining the sPDGFRß concentrations in the cerebrospinal fluid (CSF) of patients with aneurysmal SAH (aSAH) and analyzing the relationship between sPDGFRß level and CVS. CSF was sampled from 32 patients who suffered aSAH and five normal controls. Enzyme-linked immunosorbent assay was performed to determine the sPDGFRß concentrations in the CSF. Functional outcome was assessed using modified Rankin scale (mRS) at 6 months after aSAH. CVS was identified using transcranial Doppler or angio-CT or DSA. The cutoff of sPDGFRß for CVS was defined on the ROC curve. The concentrations of sPDGFRß following aSAH were both higher than those of normal controls on days 1-3 and 4-6, and peaked on days 7-9 post-SAH. The cutoff value of sPDGFRß level on days 1-3 for CVS was defined as 975.38 pg/ml according to the ROC curve (AUC = 0.680, p = 0.082). In addition, CSF sPDGFRß concentrations correlated with CVS (r = 0.416, p = 0.018), and multivariate analysis indicated that sPDGFRß level higher than 975.38 pg/ml on days 1-3 was an independent predictor of CVS (p = 0.001, OR = 19.22, 95% CI: 3.27-113.03), but not for unfavorable outcome after aSAH in the current study. CSF sPDGFRß level increases after aSAH and is higher in patients who developed CVS, and sPDGFRß level higher than 975.38 pg/ml on days 1-3 is a potential predictor for CVS after SAH.

Levels of Interleukin-1ß, Interleukin-18, and Tumor Necrosis Factor-α in Cerebrospinal Fluid of Aneurysmal Subarachnoid Hemorrhage Patients May Be Predictors of Early Brain Injury and Clinical Prognosis.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is a severe cerebrovascular accident with high morbidity and mortality. The aim of this study is to investigate the relationship between level of inflammatory cytokines in cerebrospinal fluid (CSF) of aSAH patients, the severity of aSAH, and the outcome of aSAH patients. METHODS: aSAH patients were prospectively included and followed-up for 6 months. CSF samples were collected at 1-3, 4-6, and 7-9 days after aSAH onset. Levels of interleukin (IL)-1ß, IL-18, and tumor necrosis factor-α (TNF-α) in the CSF of aSAH patients were measured by enzyme-linked immunosorbent assay. RESULTS: Eighty-one aSAH patients were enrolled. The levels of IL-1ß, IL-18 and TNF-α in the CSF were especially higher in the group of aSAH patients with cerebral edema, cerebral vasospasm, and a high grade on Hunt-Hess scale, the high World Federation of Neurological Surgeons grades, and Fisher grade (P < 0.01). Higher levels of plasma C-reactive protein in the blood were correlated with poor outcome. The areas under the receiver operating characteristic curves for the levels of inflammatory cytokines in CSF were 0.85, 0.84, and 0.95, respectively. Clinical features (age, Hunt-Hess grade, etc.) were positively correlated with poor outcomes (P < 0.05). CONCLUSIONS: The levels of IL-1ß, IL-18, and TNF-α in CSF were elevated in aSAH patients and were positively associated with cerebral edema and acute hydrocephalus. Our findings suggest that CSF inflammatory cytokines might be biomarkers to assess severity and predict outcomes.

Inhibition of leukotriene B4 synthesis protects against early brain injury possibly via reducing the neutrophil-generated inflammatory response and oxidative stress after subarachnoid hemorrhage in rats.

Leukotriene B4 (LTB4) is a highly potent neutrophil chemoattractant and neutrophils induces inflammatory response and oxidative stress when they recruit to and infiltrate in the injuried/inflamed site, such as the brain parenchyma after aneurysmal subarachnoid hemorrhage (SAH). This study is to investigate the potential effects of inhibition of LTB4 synthesis on neutrophil recruitment, inflammatory response and oxidative stress, as well as early brain injury (EBI) in rats after SAH. A pre-chiasmatic cistern SAH model of rats was used in this experiment. SC 57461A was used to inhibit LTB4 synthesis via intracerebroventricular injection. The brain tissues of temporal lobe after SAH were analyzed. Neuronal injury, brain edema and neurological function were evaluated to investigate the development of EBI. We found that inhibition of LTB4 synthesis after SAH could reduce the level of myeloperoxidase, alleviate the inflammatory response and oxidative stress, and reduce neuronal death in the brain parenchyma, and ameliorate brain edema and neurological behavior impairment at 24h after SAH. These results suggest that inhibition of LTB4 synthesis might alleviate EBI after SAH possibly via reducing the neutrophil-generated inflammatory response and oxidative stress.

Roles of Pannexin-1 Channels in Inflammatory Response through the TLRs/NF-Kappa B Signaling Pathway Following Experimental Subarachnoid Hemorrhage in Rats.

Background: Accumulating evidence suggests that neuroinflammation plays a critical role in early brain injury after subarachnoid hemorrhage (SAH). Pannexin-1 channels, as a member of gap junction proteins located on the plasma membrane, releases ATP, ions, second messengers, neurotransmitters, and molecules up to 1 kD into the extracellular space, when activated. Previous studies identified that the opening of Pannexin-1 channels is essential for cellular migration, apoptosis and especially inflammation, but its effects on inflammatory response in SAH model have not been explored yet. Methods: Adult male Sprague-Dawley rats were divided into six groups: sham group (n = 20), SAH group (n = 20), SAH + LV-Scramble-ShRNA group (n = 20), SAH + LV-ShRNA-Panx1 group (n = 20), SAH + LV-NC group (n = 20), and SAH + LV-Panx1-EGFP group (n = 20). The rat SAH model was induced by injection of 0.3 ml fresh arterial, non-heparinized blood into the prechiasmatic cistern in 20 s. In SAH + LV-ShRNA-Panx1 group and SAH + LV-Panx1-EGFP group, lentivirus was administered via intracerebroventricular injection (i.c.v.) at 72 h before the induction of SAH. The Quantitative real-time polymerase chain reaction, electrophoretic mobility shift assay, enzyme-linked immunosorbent assay, immunofluorescence staining, and western blotting were performed to explore the potential interactive mechanism between Pannexin-1 channels and TLR2/TLR4/NF-κB-mediated signaling pathway. Cognitive and memory changes were investigated by the Morris water maze test. Results: Administration with LV-ShRNA-Panx1 markedly decreased the expression levels of TLR2/4/NF-κB pathway-related agents in the brain cortex and significantly ameliorated neurological cognitive and memory deficits in this SAH model. On the contrary, administration of LV-Panx1-EGFP elevated the expressions of TLR2/4/NF-κB pathway-related agents, which correlated with augmented neuronal apoptosis. Conclusion: Pannexin-1 channels may contribute to inflammatory response and neurobehavioral dysfunction through the TLR2/TLR4/NF-κB-mediated pathway signaling after SAH, suggesting a potential role of Pannexin-1 channels could be a potential therapeutic target for the treatment of SAH.

RETRACTED: Downregulation of miR-204 expression correlates with poor clinical outcome of glioma patients.

Glioma is the most common type of malignant neoplasm in the central nervous system, with high incidence and mortality rate. MicroRNAs, as a class of small noncoding RNAs, play an important role in carcinogenesis and correlate with glioma diagnosis and prognosis. In this study, we investigated the microRNA-204 (miR-204) concentration in glioma tissues and its relation to the expression of ezrin and bcl-2 mRNA, as well as its potential predictive and prognostic values in glioma. The concentrations of miR-204 were significantly lower in glioma tissues than in nontumor brain tissues and also were lower in high-grade than in low-grade gliomas (World Health Organization grades III and IV versus grades I and II). The miR-204 concentration was inversely correlated with the ezrin and bcl-2 concentrations. The miR-204 concentration was classified as high or low according to the median value, and low miR-204 correlated with higher World Health Organization grade, larger tumor, and worse Karnofsky performance score. Kaplan-Meier survival analysis demonstrated that patients with low miR-204 expression had shorter progression-free survival and overall survival than patients with high miR-204 expression. In addition, univariate and multivariate analyses showed that miR-204 expression was an independent prognostic feature of overall survival and progression-free survival. In conclusion, our study indicates that miR-204 is downregulated in glioma and may be a biomarker of poor prognosis in patients with this cancer.

Expression and cell distribution of leukotriene B4 receptor 1 in the rat brain cortex after experimental subarachnoid hemorrhage.

Convincing evidence supports that nuclear factor kappa B (NF-κB)-meditated inflammation contributes to the adverse prognosis of aneurysmal subarachnoid hemorrhage (SAH), and pathologic neutrophil accumulation after SAH in the brain parenchyma enhances the inflammatory process. Leukotriene B4 (LTB4) is a highly potent lipid chemoattractant of neutrophils, and its biological effects are mediated primarily through the high-affinity LTB4 receptor 1 (BLT1). It is verified that NF-κB-dependent BLT1 mediates LTB4 signaling and LTB4 stimulates NF-κB-dependent inflammation via BLT1. This study aimed to determine the expression and cell distribution of BLT1 in the brain cortex after SAH and investigate the potential relationship between protein expressions of BLT1 and NF-κB. Male Sprague-Dawley rats were randomly assigned into sham group and SAH groups at 6h, 12h and on day 1, day 2 and day 3 (n=6 for each subgroup). SAH groups suffered experimental SAH by injecting 0.3ml autologous blood into the prechiasmatic cistern. BLT1 expression was measured by real-time PCR, western blot, immunohistochemistry and immunofluorescence. Nuclear expression of p65 protein, the major subunit of NF-κB, was also detected by western blot. Our data showed that the expression levels of BLT1 and nuclear p65 protein were both markedly increased after SAH. Moreover, there was a significant positive correlation between BLT1 and nuclear p65 protein expressions in the same specific time course. Double immunofluorescence staining showed that BLT1 were mainly expressed in neurons, microglia and endothelial cells rather than astrocytes after SAH. These results suggest that BLT1 may participate in the NF-κB-mediated inflammatory response after SAH, and there might be important implications for further studies using specific BLT1 antagonists to attenuate the NF-κB-mediated inflammation after SAH.

Elevated cerebrospinal fluid levels of thrombospondin-1 correlate with adverse clinical outcome in patients with aneurysmal subarachnoid hemorrhage.

BACKGROUND: Thrombospondin-1 (TSP-1) is a homotrimeric glycoprotein which modulates a wide range of biological functions. Elevated level of TSP-1 in plasma was reported to be correlated with intracerebral hemorrhage. Our study was designed to investigate the relationship between cerebrospinal fluid (CSF) TSP-1 levels and clinical outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH). METHODS: CSF TSP-1 levels were measured in 31 aSAH patients on days 1-3, days 5-7 and days 8-10 after aSAH onset using enzyme-linked immunosorbent assay. Patients were under a close follow-up until death or completion of three months after aSAH. Binary logistic regression analyses were performed to determine independent risk factors for the clinical outcomes. RESULTS: TSP-1 levels peaked on days 1-3 after aSAH, kept up high on days 5-7 and remained elevated until days 8-10 (p<0.05). Significant elevation of CSF TSP-1 levels were found in patients both with and without vasospasm. Modified Rankin Scale at 3months after aSAH showed a significant correlation with CSF TSP-1 levels on days 1-3 and days 5-7 (both p<0.01). Binary logistic regression analysis showed that higher TSP-1 level on days 1-3 (p<0.05) and on days 5-7 (p<0.05) was a predictive marker of cerebrovasospasm and poor outcome of patient with aSAH. CONCLUSIONS: Upregulation of TSP-1 may involve in the pathological process of aSAH and might be a risk factor of future adverse prognosis of aSAH.

Resveratrol Attenuates Acute Inflammatory Injury in Experimental Subarachnoid Hemorrhage in Rats via Inhibition of TLR4 Pathway.

Toll-like receptor 4 (TLR4) has been proven to play a critical role in neuroinflammation and to represent an important therapeutic target following subarachnoid hemorrhage (SAH). Resveratrol (RSV), a natural occurring polyphenolic compound, has a powerful anti-inflammatory property. However, the underlying molecular mechanisms of RSV in protecting against early brain injury (EBI) after SAH remain obscure. The purpose of this study was to investigate the effects of RSV on the TLR4-related inflammatory signaling pathway and EBI in rats after SAH. A prechiasmatic cistern SAH model was used in our experiment. The expressions of TLR4, high-mobility group box 1 (HMGB1), myeloid differentiation factor 88 (MyD88), and nuclear factor-κB (NF-κB) were evaluated by Western blot and immunohistochemistry. The expressions of Iba-1 and pro-inflammatory cytokines in brain cortex were determined by Western blot, immunofluorescence staining, or enzyme-linked immunosorbent assay. Neural apoptosis, brain edema, and neurological function were further evaluated to investigate the development of EBI. We found that post-SAH treatment with RSV could markedly inhibit the expressions of TLR4, HMGB1, MyD88, and NF-κB. Meanwhile, RSV significantly reduced microglia activation, as well as inflammatory cytokines leading to the amelioration of neural apoptosis, brain edema, and neurological behavior impairment at 24 h after SAH. However, RSV treatment failed to alleviate brain edema and neurological deficits at 72 h after SAH. These results indicated that RSV treatment could alleviate EBI after SAH, at least in part, via inhibition of TLR4-mediated inflammatory signaling pathway.

Inhibition of myeloid differentiation factor 88(MyD88) by ST2825 provides neuroprotection after experimental traumatic brain injury in mice.

Myeloid differentiation factor 88(MyD88) is an endogenous adaptor protein that plays an important role in coordinating intracellular inflammatory responses induced by agonists of the Toll-like receptor and interleukin-1 receptor families. MyD88 has been reported to be essential for neuronal death in animal models and may represent a therapeutic target for pharmacologic inhibition following traumatic brain injury (TBI). The purpose of the current study was to investigate the neuroprotective effect of MyD88 specific inhibitor ST2825 in an experimental mouse model of TBI. Intracerebroventricular (ICV) injection of high concentration (20µg/µL) ST2825 (15min post TBI) attenuated the development of TBI in mice, markedly improved neurological function and reduced brain edema. Decreased neural apoptosis and increased neuronal survival were also observed. Biochemically, the high concentration of ST2825 significantly reduced the levels of MyD88, further decreased TAK1, p-TAK1, nuclear p65 and increased IκB-α. Additionally, ST2825 significantly reduced the levels of Iba-1 and inflammatory factors TNF-α and IL-1ß. These data provide an experimental rationale for evaluation of MyD88 as a drug target and highlight the potential therapeutic implications of ST2825 in TBI.