Inhibition of Heat Shock Protein 90 Attenuates the Damage of Blood-Brain Barrier Integrity in Traumatic Brain Injury Mouse Model.

Heat shock protein 90 (HSP90) is widely found in brain tissue. HSP90 inhibition has been proven to have neuroprotective effects on ischemic strokes. In order to study the role of HSP90 in traumatic brain injury (TBI), we carried out the present study. A novel inhibitor of the HSP90 protein, 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DA), has been investigated for its function on the blood-brain barrier (BBB) damage after traumatic brain injury (TBI) in mouse models. These C57BL/6 mice were used as a TBI model and received 17-DA (0.1 mg/kg/d, intraperitoneally) until the experiment ended. To find out whether 17-DA may protect against TBI in vitro, bEnd.3 cells belonging to mouse brain microvascular endothelium were used. The HSP90 protein expressions were raised after TBI at the pericontusional area, especially at 3 d. Our study suggested that 17-DA-treated mice improved the recovery ability of neurological deficits and decreased brain edema, Evans blue extravasation, and the loss of tight junction proteins (TJPs) post-TBI. 17-DA significantly promoted cell proliferation and alleviated apoptosis by inhibiting the generation of intracellular reactive oxygen species (ROS) to downregulate cleaved caspase-3, matrix metallopeptidase- (MMP-) 2, MMP-9, and P-P65 in bEnd.3 cells after the injury. As a result, we assumed that the HSP90 protein was activated post-TBI, and inhibition of HSP90 protein reduced the disruption of BBB and improved the neurobehavioral scores in a mouse model of TBI through the action of 17-DA, which inhibited ROS generation and regulated MMP-2, MMP-9, NF-κB, and caspase-associated pathways. Thus, blocking HSP90 protein may be a potential therapeutic strategy for TBI.

miR-124 upregulates astrocytic glutamate transporter-1 via the Akt and mTOR signaling pathway post ischemic stroke.

High-concentration glutamic acid (Glu) induced by ischemic stroke can be inhibited by glutamate transporter-1 (GLT-1), which is the main mechanism for preventing excessive extracellular glutamate accumulation in the central nervous system. Upregulation of miR-124 could reduce the infarct area and promote the recovery of neurological function after ischemic stroke. A previous study investigated whether miR-124 could regulate GLT-1 expression in normal culture conditions. However, the role of miR-124 in the regulation of GLT-1 expression and further mechanisms after ischemic stroke remain unclear. In this study, the effects of miR-124 on GLT-1 expression in astrocytes after ischemic stroke were explored using an in vitro model of ischemic stroke (oxygen-glucose deprivation/reperfusion, OGD/reperfusion). The expression of GLT-1 was significantly decreased with lower expression of miR-124 in astrocytes injured by OGD/reperfusion. When miR-124 expression was improved, the expression of GLT-1 was notably increased in astrocytes injured by OGD/reperfusion. The results revealed that GLT-1 expression in astrocytes had a relationship with miR-124 after OGD/reperfusion. However, a direct interaction could not be confirmed with a luciferase reporter assay. Further results demonstrated that an inhibitor of Akt could decrease the increased protein expression of GLT-1 induced by miR-124 mimics, and an inhibitor of mTOR could increase the reduced protein expression of GLT-1 caused by a miR-124 inhibitor in astrocytes injured by different OGD/reperfusion conditions. These results indicated that miR-124 could regulate GLT-1 expression in astrocytes after OGD/reperfusion through the Akt and mTOR pathway.

Association between inflammatory cytokines and the risk of post-stroke depression, and the effect of depression on outcomes of patients with ischemic stroke in a 2-year prospective study.

The association between inflammatory cytokines and the risk of post-stroke depression (PSD) remains unclear. The aim of the present study was to investigate this association and the effect of PSD on the outcomes of ischemic stroke patients. A total of 355 patients who had experienced ischemic stroke participated in inflammatory cytokine detection by ELISA, in addition to depression, quality of life (QOL) and body performance testing. Cox regression was used to evaluate the associations between PSD risk, inflammatory cytokines and the outcomes of patients. Measurement data was evaluated using Student's t test, and counted data was measured by χ2 test. The incidence of PSD during the 2-year follow-up was 23.1%. The risk of PSD elevated with increased interleukin (IL)-6 expression levels [hazard ratio (HR)=3.18; 95% confidence interval (CI), 1.37-7.36] following the adjustment of confounders. However, no significant associations were identified between PSD and other inflammatory cytokines. QOL and body performance in the depressed group were significantly worse compared with those in the non-depressed group. The risk of stroke recurrence in patients with depression increased two-fold compared with patients without depression (HR=2.020; 95% CI, 1.123-3.635; Ptrend=0.019). No significant associations between PSD and the risk of mortality (HR=1.497; 95% CI, 0.547-4.098) were observed. In conclusion, depression is prevalent in patients following ischemic stroke. IL-6 is positively associated with the risk of PSD, and may predict its development in patients following ischemic stroke. PSD correlates with outcomes of patients, and the effective management of PSD may improve the prognosis of patients.

Curcumin induces G2/M arrest and triggers apoptosis via FoxO1 signaling in U87 human glioma cells.

It has previously been demonstrated that curcumin possesses an antitumor activity, which is associated with its ability to induce G2/M cell cycle arrest and apoptosis. However the detailed underlying mechanisms remain unclear. The present study aimed to investigate the efficacy and underlying mechanism of curcumin­induced cell cycle arrest and apoptosis in U87 human glioblastoma cells. By immunofluorescence staining, subcellular fractionation and western blotting, the present study demonstrated that curcumin was able to induce G2/M cell cycle arrest and apoptosis by increasing the expression levels of cyclin G2, cleaved caspase­3 and Fas ligand (FasL), and decreasing the expression of cyclin­dependent kinase 1 (CDK1). In addition, increased expression of forkhead box protein O1 (FoxO1) and decreased expression of phosphorylated (p)­FoxO1 were detected in the curcumin­treated U87 cells. Curcumin was also able to induce the translocation of FoxO1 from the cytoplasm to the nucleus. Furthermore, following knockdown of FoxO1 expression in curcumin­treated U87 cells using FoxO1 small interfering RNA, the expression levels of cyclin G2, cleaved caspase­3 and FasL were inhibited; however, the expression levels of CDK1 were not markedly altered. Notably, following knockdown of CDK1 expression under normal conditions, the total expression of FoxO1 was not affected; however, p­FoxO1 expression was decreased and FoxO1 nuclear expression was increased. Furthermore, curcumin­induced G2/M cell cycle arrest and apoptosis could be attenuated by FoxO1 knockdown. These results indicated that curcumin may induce G2/M cell cycle arrest and apoptosis in U87 cells by increasing FoxO1 expression. The present study identified a novel mechanism underlying the antitumor effects of curcumin, and may provide a theoretical basis for the application of curcumin in glioma treatment.

Relationship between inflammatory cytokines and risk of depression, and effect of depression on the prognosis of high grade glioma patients.

Depression is found to be associated with up-regulation of inflammatory cytokines. However, the relationship in high grade glioma (HGG) patients is still unclear. In this prospective study, a total 132 HGG patients participated in blood sample collection for inflammatory cytokines detection by ELISA, mental status, quality of life (QOL) and physical functional status testing. The association between inflammatory cytokines and depression risk was assessed using conditional logistic regression. The incidences of depressive symptoms and depression in high grade glioama patients were 45.5 and 25 % respectively during 12 months follow-up. We found the risk of depression was elevated with increased C-reactive protein (CRP) and interleukin-6 (IL-6) in high grade glioma patients after adjustment of confounders. The serum levels of CRP and IL-6 in patients with transient depression and depression were higher than those without depressive symptoms. In addition, depression had significant effects on the survival, QOL and physical functional status of patients. Depression is prevalent among patients with HGG. The present study suggests that serum CRP and IL-6 may serve as a depression marker for HGG patients. The survival and quality of life of HGG patients may be improved by an effective management for depression.

Metabolic syndrome factors and risk of postoperative depression in high-grade glioma patients in a 1.5-year prospective study.

To date, the relationship between metabolic syndrome factors and the risk of glioma-related depression is still unclear, and no study investigates this relationship. Our aim was to investigate the relationship between metabolic syndrome factors and the risk of postoperative depression in high-grade patients. A total of 386 high-grade glioma patients participated in blood sample collection for metabolic syndrome factors analysis and the hospital anxiety and depression scale testing. The association between metabolic syndrome factors and the risk of postoperative depression was assessed using Cox regression proportional hazards models, and Student's t tests were used to evaluate the differences in demographic variables and clinical characteristics in subgroups. The incidence of postoperative depression in our 1.5-year follow-up was 30.5%. We found the risk of postoperative depression was elevated with increased blood glucose level [hazard ratios (HR) 2.277, 95% confidence interval (CI) 1.201-4.320, top vs. bottom quartile]. The hazard ratio was increased for z-scores of blood glucose (HR 1.672 per unit standard deviation, 95% CI 1.311-2.133] and of the combined metabolic syndrome score (HR 1.080, 95% CI 1.000-1.167). In addition, risk of postoperative depression risk was increased in high-grade glioma patients with high blood glucose levels (≥6.0 mmol/l) (HR 2.084, 95% CI 1.235-3.515). However, we did not find significant associations between postoperative depression and other metabolic syndrome factors, including body mass index, systolic blood pressure, diastolic blood pressure, cholesterol, and triglycerides. Depression is prevalent among patients with high-grade glioma after operation. Blood glucose level is positively associated with the risk of postoperative depression, and might be involved in the etiology of postoperative depression, and may predict its development in high-grade glioma patients.

Relationship between concentrations of IGF-1 and IGFBP-3 and preoperative depression risk, and effect of psychological intervention on outcomes of high-grade glioma patients with preoperative depression in a 2-year prospective study.

Growth factors in the brain are important to depression. We investigated the relationship between serum insulin-like growth factor (IGF-1) and IGF-binding protein-3 (IGFBP-3) concentration and risk of depression and the effect of psychological intervention on outcomes of high-grade glioma patients with preoperative depression. A total of 249 high-grade glioma patients participated in blood sample collection for IGF-1 and IGFBP-3 detection by ELISA and the Hospital Anxiety and Depression Scale testing. The association between IGF-I or IGFBP-3 and depression risk was assessed using conditional logistic regression, and Student's t tests were used to evaluate differences in change of the Karnofsky Performance Status Scale (KPS) in subgroups after performance of psychosocial intervention. The survivals of patients in subgroups were tested by Kaplan-Meier (log-rank test). We found the risk of depression was elevated with increased IGF-I (HR = 6.320, 95% CI 2.456-16.265, top vs. bottom quartile) and IGFBP-3 concentrations (HR = 3.411, 95% CI 1.345-8.648) after adjustment of confounders. KPS was increased significantly in the intervention groups, but not significantly in the usual care groups after performance of psychosocial intervention. The survival of depressed patients in the usual group was significantly worse than those of other subgroups after performance of psychosocial intervention. Depression is prevalent among patients with high-grade gliomas, and factors of the IGF axis are positively associated with risk of depression and might be involved in the etiology of depression in high-grade glioma patients. Depression correlates with quality of life and outcomes of patients. Therefore, some psychological interventions are needed and may help patients to relieve depression and improve the life quality of glioma patients.