Effect of HMGB1 and RAGE on brain injury and the protective mechanism of glycyrrhizin in intracranial­sinus occlusion followed by mechanical thrombectomy recanalization.

The key to successful treatment of cerebral venous­sinus occlusion (CVO) is the rapid recanalization of the sinus following venous­sinus occlusion; however, rapid recanalization of the sinus may also cause secondary cerebral injury. The present study examined mechanical thrombectomy­related brain injury and the possible molecular mechanisms following CVO recanalization, and investigated the protective effect of glycyrrhizin (GL) in CVO recanalization. The cerebral venous sinus thrombosis (CVST) model was induced in rats using 40% FeCl3. Mechanical thrombectomy was performed at 6 h post­thrombosis. GL was administered to rats following thromboembolism. Neurological function and brain water content were measured prior to sacrifice of the rats. Serum malondialdehyde, superoxide dismutase and nitric­oxide synthase concentrations were measured. The expression levels of high­mobility group box 1 (HMGB1) and receptor of advanced glycation end products (RAGE) and its downstream inflammatory mediators were measured in serum and brain tissues. Rapid CVO recanalization caused brain injury, and the brain parenchymal damage and neurological deficits caused by CVO were not completely restored following recanalization. Similarly, following rapid recanalization in the venous sinus, the expression levels of HMGB1 and RAGE were lower than those in the CVST group, but remained significantly higher than those of the sham group. The combination of mechanical thrombectomy and GL improved cerebral infarction and cerebral edema in rats, and inhibited the extracellular transport of HMGB1, and the expression of downstream inflammatory factors and oxidative­stress products. The administration of exogenous recombinant HMGB1 reversed the neural protective effects of GL. In conclusion, mechanical thrombectomy subsequent to CVO in rats can cause brain injury following recanalization. HMGB1 and RAGE promote inflammation in the process of brain injury following recanalization. GL has a relatively reliable neuroprotective effect on brain injury by inhibiting HMGB1 and its downstream inflammatory factors, and decreasing oxidative stress.

Suppression of microRNA-130b inhibits glioma cell proliferation and invasion, and induces apoptosis by PTEN/AKT signaling.

Glioblastoma is the most common malignant brain tumor in adults and is characterized by extensive proliferation and the diffused invasion of tumor cells. Due to the intricate signaling pathways involved in glioma progression, more effective targeted therapies and prognostic biomarkers in clinical practice are required. The suppression of proto-oncogene function or recovery of tumor suppressor gene function remains one of the primary approaches in gene therapy. The close association between the abnormal expression or mutation of microRNA (miRNA) and the tumorigenesis, progression and staging in glioma have been demonstrated previously. However, the expression pattern and specific role of microRNA­130b (miR­130b) in the tumor occurrence and progression of glioma are unclear. In the present study, quantitative polymerase chain reaction was performed to determine the expression level of miR-130b in 30 brain glioma patients and 3 glioma cell lines. An miR­130b inhibitor was transfected into U87 cells to downregulate the expression of miR-130b, and assessments of cell proliferation, cell cycle, apoptosis, cell invasion and migration in vitro and nude mouse tumorigenicity in vivo were conducted. Western blotting and luciferase reporter gene technology were used to verify the downstream target gene of miR-130b, namely phosphatase and tensin homolog (PTEN). The results demonstrated that miR-130b expression was increased in glioma tissues and cell lines in comparison with non-glioma tissues or cells. The downregulated expression of miR-130b inhibited the proliferation and invasion of glioma cells, induced apoptosis of the cells in vitro and inhibited their tumorigenicity in vivo. Western blotting and luciferase reporter assays demonstrated that the PTEN gene is a direct target of miR­130b. Western blotting revealed that the miR-130b inhibitor upregulated the expression of PTEN, inhibited AKT pathway activation, upregulated the tumor suppressor gene p27, and suppressed cyclin D1, matrix metalloproteinase 2 and 9 expression. These results suggest that the miR-130b inhibitor suppressed glioma cell proliferation and invasion via the PTEN/AKT pathway. Therefore, miR­130b is suggested to be an effective therapeutic target for glioma.

miR-130b regulates the proliferation, invasion and apoptosis of glioma cells via targeting of CYLD.

MicroRNAs are short non-coding RNAs that play important roles in gliomas. However, the role of miR-130b in glioma remains unclear. In the present study, miR-130b expression was upregulated in glioma tissues and cell lines. Kaplan-Meier analysis indicated that the upregulation of miR-130b expression correlated with poor prognoses in glioma patients. Multivariate analysis demonstrated that this upregulation and a high-grade classification were independent factors that both predicted poor outcomes for glioma patients. Dual-luciferase assays identified that the cylindromatosis (CYLD) gene is a direct target of miR-130b. Functional studies demonstrated that a miR-130b mimic significantly promoted the growth and invasion of glioma cells, while also inhibiting apoptosis via selective targeting of CYLD, which was enhanced by CYLD-targeted siRNA. In contrast, a miR­130b inhibitor suppressed these biological behaviors, and this inhibition was reversed by CYLD-targeted siRNA. These data revealed that miR-130b could act as a novel potential diagnostic biomarker for glioma, while also demonstrating the importance of miR­130b in the cell proliferation and progression of glioma, indicating that it may serve as a useful therapeutic target for glioma.

Analysis of Factors Related to Hypopituitarism in Patients with Nonsellar Intracranial Tumor.

OBJECTIVE: Previous studies have suggested that postoperative hypopituitarism in patients with nonsellar intracranial tumors is caused by traumatic surgery. However, with development of minimally invasive and precise neurosurgical techniques, the degree of injury to brain tissue has been reduced significantly, especially for parenchymal tumors. Therefore, understanding preexisting hypopituitarism and related risk factors can improve perioperative management for patients with nonsellar intracranial tumors. METHODS: Chart data were collected retrospectively from 83 patients with nonsellar intracranial tumors admitted to our hospital from May 2014 to April 2015. Pituitary function of each subject was determined based on results of preoperative serum pituitary hormone analysis. Univariate and multivariate logistic regression methods were used to analyze relationships between preoperative hypopituitarism and factors including age, sex, history of hypertension and secondary epilepsy, course of disease, tumor mass effect, site of tumor, intracranial pressure (ICP), cerebrospinal fluid content, and pituitary morphology. RESULTS: A total of 30 patients (36.14%) presented with preoperative hypopituitarism in either 1 axis or multiple axes; 23 (27.71%) were affected in 1 axis, and 7 (8.43%) were affected in multiple axes. Univariate analysis showed that risk factors for preoperative hypopituitarism in patients with a nonsellar intracranial tumor include an acute or subacute course (≤3 months), intracranial hypertension (ICP >200 mm H2O), and mass effect (P < 0.05). Multivariate logistic regression analysis showed that mass effect is an independent risk factor for preoperative hypopituitarism in patients with nonsellar intracranial tumors (P < 0.05; odds ratio, 3.197). CONCLUSIONS: Prevalence of hypopituitarism is high in patients with nonsellar intracranial tumors. The occurrence of hypopituitarism is correlated with factors including an acute or subacute course (≤3 months), intracranial hypertension (ICP >200 mm H2O), and mass effect (P < 0.05). Mass effect is an independent risk factor for hypopituitarism.

Recombinant human soluble thrombomodulin protects against brain injury in a CVST rat model, via downregulation of the HMGB1-RAGE axis.

Cerebral venous sinus thrombosis (CVST) is a distinct cerebrovascular disorder, and ~50% of CVST patients progress to cerebral venous infarction, resulting in elevation of cerebral venous pressure. Anticoagulation is the standard initial treatment and is associated with a reduced relative risk of mortality and dependency. Recombinant human soluble thrombomodulin (rhs­TM) is a promising therapeutic natural anticoagulant comparable to antithrombin, tissue factor pathway inhibitor, and activated protein C. The present study aimed to investigate the protective effects of rhs­TM in a CVST rat model, and identify any underlying mechanisms. Rats were treated with rhs­TM intravenously prior to CVST. Following neurological function evaluation, animals were sacrificed and brain water content and infarct volume were assessed. Brain tissue was collected from the infarcted segments and mRNA and protein expression levels of high mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE), tumor necrosis factor (TNF)­α, interleukin (IL)­1ß, IL­6, caspase­3, B­cell lymphoma­2 and Bcl­2 associated X were analyzed by reverse transcription-quantitative polymerase chain reaction and western blot analysis. rhs­TM significantly prevented neurological deficits in locomotor function and reduced infarct volume. The expression levels of HMGB1­RAGE were upregulated in the infarcted segments of rat brains following CVST. Pretreatment with rhs­TM inhibited the HMGB1­RAGE axis, alleviating the expression levels of the proinflammatory cytokines, TNF­α, IL­1ß and IL­6; however, expression levels of the apoptosis-associated genes and proteins remained unaffected. The results of the present study indicated that rhs­TM protects against CVST in the rat model via inhibition of the HMGB1­RAGE axis and inflammation, but not via apoptosis.

MicroRNA-130b promotes cell proliferation and invasion by inhibiting peroxisome proliferator-activated receptor-γ in human glioma cells.

MicroRNA-130b (miR-130b) is a novel tumor-related miRNA that has been found to be involved in several biological processes. However, there is limited evidence regarding the role of miR-130b in the tumorigenesis of human gliomas. In the present study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays were used to quantify miR-130b expression levels in human glioma tissues and glioma cell lines (U251, U87, SNB19 and LN229). The expression level of miR-130b was found to be markedly higher in human glioma tissues than in non­neoplastic brain specimens. Specifically, higher expression levels of miR­130b were observed in the glioma cell lines, compared with those in normal human astrocytes (NHA). We also confirmed that miR­130b interacted with the 3'-untranslated region of peroxisome proliferator­activated receptor-γ (PPAR­Î³), which negatively affected the protein levels of E-cadherin. Furthermore, its effects on cell proliferation and invasion were examined using CCK8, colony formation, cell cycle and Transwell assays. We found that the upregulation of miR-130b induced cell proliferation, decreased the percentage of cells in the G0/G1 phase and enhanced the invasiveness of U251 glioma cells whereas the downregulation of miR-130b exerted opposing effects. Moreover, it was demonstrated that the downregulation of miR­130b in U251 glioma cells restored the expression of PPAR-γ and E-cadherin, and inhibited the expression of ß-catenin. Notably, PPAR-γ knockdown abolished the inhibitory effect of miR-130b inhibitor on the proliferation and invasivness of U251 cells. Taken together, these findings suggest that miR­130b promotes the proliferation and invasion of U251 glioma cells by inhibiting PPAR-γ.

TPX2 promotes glioma cell proliferation and invasion via activation of the AKT signaling pathway.

Glioblastoma multiforme (GBM) is the most common and most malignant type of primary adult brain cancer. The most common phenotype associated with GBM is cellular invasion; however, the molecular mechanisms governing this process are poorly understood. Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a nuclear protein with roles in cellular proliferation and mitotic spindle assembly. TPX2 is overexpressed in various malignancies, including human malignant astrocytoma. Despite this finding, the exact role of TPX2 in human glioma is not well defined. The present study reports the elevated expression of TPX2 in a number of glioma cell lines. TPX2 overexpression promoted cellular proliferation, decreased the percentage of cells in G0/G1 phase, and increased invasion of both U251 and U87 cells. Overexpression of TPX2 also significantly enhanced the phosphorylation of AKT, decreased the expression of p21, and increased the expression of cyclin D1 and matrix metallopeptidase (MMP)-9. In both U251 and U87 cells, knockdown of TPX2 resulted in phenotypes that are in direct contrast to those observed following TPX2 overexpression. Specifically, TPX2 knockdown inhibited cell proliferation, increased the percentage of cells in G0/G1 phase, inhibited invasion, decreased AKT phosphorylation, decreased the expression of MMP-9 and cyclin D1, and increased p21 expression. The AKT inhibitor IV in large part phenocopied the effect of TPX2 knockdown. The present data suggest that TPX2 promotes glioma cell proliferation and invasion via AKT signaling.