Telmisartan inhibits microglia-induced neurotoxic A1 astrocyte conversion via PPARγ-mediated NF-κB/p65 degradation.

Astrocytes are crucially involved in neuroinflammation. Activated astrocytes exhibit at least two phenotypes, A1 (neurotoxic) and A2 (neuroprotective). The A1 phenotype is the major reactive astrocyte phenotype involved in aging and neurodegenerative diseases. Telmisartan, which is an antihypertensive agent, is a promising neuroprotective agent. This study aimed to investigate the effects of telmisartan on the phenotype of reactive astrocytes. Astrocytes were activated by culturing with the conditioned medium derived from lipopolysaccharide-stimulated microglia. This conditioned medium induced early, transient A2 astrocyte conversion (within 24 h) and late, sustained A1 conversion (beginning at 24 h and lasting up to 7 days), with a concomitant increase in the production of pro-inflammatory cytokines (interleukin [IL]-1ß, tumor necrosis factor [TNF]α, and IL-6) and phosphorylation of nuclear factor-κB (NF-κB)/p65. Telmisartan treatment promoted and inhibited A2 and A1 conversion, respectively. Telmisartan reduced total and phosphorylated p65 protein levels. Losartan, a specific angiotensin II type-1 receptor (AT1R) blocker, did not influence the reactive state of astrocytes. Additionally, AT1R activation by angiotensin II did not induce the expression of pro-inflammatory cytokines and A1/A2 markers, indicating that the AT1R signaling pathway is not involved in the astrocyte-mediated inflammatory response. A peroxisome proliferator-activated receptor γ (PPARγ) antagonist reversed the effects of telmisartan. Moreover, telmisartan-induced p65 downregulation was reversed by the proteasome inhibitor MG132. These results indicate that telmisartan suppresses activated microglia-induced neurotoxic A1 astrocyte conversion through p65 degradation. Our findings contribute towards the elucidation of the anti-inflammatory activity of telmisartan in brain disorders.

Development and Validation of a Deep Learning Predictive Model Combining Clinical and Radiomic Features for Short-Term Postoperative Facial Nerve Function in Acoustic Neuroma Patients.

OBJECTIVE: This study aims to construct and validate a predictable deep learning model associated with clinical data and multi-sequence magnetic resonance imaging (MRI) for short-term postoperative facial nerve function in patients with acoustic neuroma. METHODS: A total of 110 patients with acoustic neuroma who underwent surgery through the retrosigmoid sinus approach were included. Clinical data and raw features from four MRI sequences (T1-weighted, T2-weighted, T1-weighted contrast enhancement, and T2-weighted-Flair images) were analyzed. Spearman correlation analysis along with least absolute shrinkage and selection operator regression were used to screen combined clinical and radiomic features. Nomogram, machine learning, and convolutional neural network (CNN) models were constructed to predict the prognosis of facial nerve function on the seventh day after surgery. Receiver operating characteristic (ROC) curve and decision curve analysis (DCA) were used to evaluate model performance. A total of 1050 radiomic parameters were extracted, from which 13 radiomic and 3 clinical features were selected. RESULTS: The CNN model performed best among all prediction models in the test set with an area under the curve (AUC) of 0.89 (95% CI, 0.84-0.91). CONCLUSION: CNN modeling that combines clinical and multi-sequence MRI radiomic features provides excellent performance for predicting short-term facial nerve function after surgery in patients with acoustic neuroma. As such, CNN modeling may serve as a potential decision-making tool for neurosurgery.

Genetic alteration and clonal evolution of primary glioblastoma into secondary gliosarcoma.

AIMS: Secondary gliosarcoma (SGS) rarely arises post treatment of primary glioblastoma multiforme (GBM), and contains gliomatous and sarcomatous components. The origin and clonal evolution of SGS sarcomatous components remain uncharacterized. Therapeutic radiation is mutagenic and can induce sarcomas in patients with other tumor phenotypes, but possible causal relationships between radiotherapy and induction of SGS sarcomatous components remain unexplored. Herein, we investigated the clonal origin of SGS in a patient with primary GBM progressing into SGS post-radiochemotherapy. METHODS: Somatic mutation profile in GBM and SGS was examined using whole-genome sequencing and deep-whole-exome sequencing. Mutation signatures were characterized to investigate relationships between radiochemotherapy and SGS pathogenesis. RESULTS: A mutation cluster containing two founding mutations in tumor-suppressor genes NF1 (variant allele frequency [VAF]: 50.0% in GBM and 51.1% in SGS) and TP53 (VAF: 26.7% in GBM and 50.8% in SGS) was shared in GBM and SGS. SGS exhibited an overpresented C>A (G>T) transversion (oxidative DNA damage signature) but no signature 11 mutations (alkylating-agents - exposure signature). Since radiation induces DNA lesions by generating reactive oxygen species, the mutations observed in this case of SGS were likely the result of radiotherapy rather than chemotherapy. CONCLUSIONS: Secondary gliosarcoma components likely have a monoclonal origin, and the clone possessing mutations in NF1 and TP53 was likely the founding clone in this case of SGS.

Effect of subarachnoid anesthesia combined with propofol target-controlled infusion on blood loss and transfusion for posterior total hip arthroplasty in elderly patients.

BACKGROUND: Intravertebral and general anesthesia (GA) are two main anesthesia approaches but both have defects. This study was aimed to evaluate the effect of subarachnoid anesthesia combined with propofol target-controlled infusion (TCI) on blood loss and transfusion for total hip arthroplasty (THA) in elderly patients in comparison with combined spinal-epidural anesthesia (CSEA) or GA. METHODS: Totally, 240 patients (aged ≥65 years, American Society of Anesthesiologists [ASA] I-III) scheduled for posterior THA were enrolled from September 1st, 2017 to March 1st, 2018. All cases were randomly divided into three groups to receive CSEA (group C, n = 80), GA (group G, n = 80), or subarachnoid anesthesia and propofol TCI (group T, n = 80), respectively. Primary outcomes measured were intra-operative blood loss, autologous and allogeneic blood transfusion, mean arterial pressure at different time points, length of stay in post-anesthesia care unit (PACU), length of hospital stay, and patient satisfaction degree. Furthermore, post-operative pain scores and complications were also observed. The difference of quantitative index between groups were analyzed by one-way analysis of variance, repeated measurement generalized linear model, Student-Newman-Keuls test or rank-sum test, while ratio index was analyzed by Chi-square test or Fisher exact test. RESULTS: Basic characteristics were comparable among the three groups. Intra-operative blood loss in group T (331.53 ±â€Š64.33 mL) and group G (308.03 ±â€Š64.90 mL) were significantly less than group C (455.40 ±â€Š120.48 mL, F = 65.80, P < 0.001). Similarly, the autologous transfusion of group T (130.99 ±â€Š30.36 mL) and group G (124.09 ±â€Š24.34 mL) were also markedly less than group C (178.31 ±â€Š48.68 mL, F = 52.99, P < 0.001). The allogenetic blood transfusion of group C (0 [0, 100.00]) was also significantly larger than group T (0) and group G (0) (Z = 2.47, P = 0.047). Except for the baseline, there were significant differences in mean arterial blood pressures before operation (F = 496.84, P < 0.001), 10-min after the beginning of operation (F = 351.43, P < 0.001), 30-min after the beginning of operation (F = 559.89, P < 0.001), 50-min after the beginning of operation (F = 374.74, P < 0.001), and at the end of operation (F = 26.14, P < 0.001) among the three groups. Length of stay in PACU of group T (9.41 ±â€Š1.19 min) was comparable with group C (8.83 ±â€Š1.26 min), and both were significantly shorter than group G (16.55 ±â€Š3.10 min, F = 352.50, P < 0.001). There were no significant differences among the three groups in terms of length of hospitalization and post-operative visual analog scale scores. Patient satisfaction degree of group T (77/80) was significantly higher than group C (66/80, χ = 7.96, P = 0.004) and G (69/80, χ = 5.01, P = 0.025). One patient complained of post-dural puncture headache and two complained of low back pain in group C, while none in group T. Incidence of post-operative nausea and vomiting in group G (10/80) was significantly higher than group T (3/80, χ = 4.10, P = 0.043) and group C (2/80, χ = 5.76, P = 0.016). No deep vein thrombosis or delayed post-operative functional exercise was detected. CONCLUSIONS: Single subarachnoid anesthesia combined with propofol TCI seems to perform better than CSEA and GA for posterior THA in elderly patients, with less blood loss and peri-operative transfusion, higher patient satisfaction degree and fewer complications. TRIAL REGISTRATION: chictr.org.cn: ChiCTR-IPR-17013461; http://www.chictr.org.cn/showproj.aspx?proj=23024.

The Clinical Significance of O6-Methylguanine-DNA Methyltransferase Promoter Methylation Status in Adult Patients With Glioblastoma: A Meta-analysis.

BACKGROUND AND OBJECTIVE: Promoter status of O6-methylguanine-DNA methyltransferase (MGMT) has been widely established as a clinically relevant factor in glioblastoma (GBM) patients. However, in addition to varied therapy schedule, the prognosis of GBM patients is also affected by variations of age, race, primary or recurrent tumor. This study comprehensively investigated the association between MGMT promoter status and prognosis in overall GBM patients and in different GBM subtype including new diagnosed patients, recurrent patients and elderly patients. METHODS: A comprehensive search was performed using PubMed, EMBASE, Cochrane databases to identify literatures (published from January 1, 2005 to April 1, 2017) that evaluated the associations between MGMT promoter methylation and prognosis of GBM patients. RESULTS: Totally, 66 studies including 7,886 patients met the inclusion criteria. Overall GBM patients with a methylated status of MGMT receiving temozolomide (TMZ)-containing treatment had better overall survival (OS) and progression-free survival (PFS) [OS: hazard ratio (HR) = 0.46, 95% confidence interval (CI): 0.41-0.52, p < 0.001, Bon = 0.017; PFS: HR = 0.48, 95% CI 0.40-0.57, p < 0.001, Bon = 0.014], but no significant advantage on OS or PFS in GBM patients with TMZ-free treatment was observed (OS: HR = 0.97, 95% CI 0.91-1.03, p = 0.08, Bon = 1; PFS: HR = 0.76, 95% CI 0.57-1.02, p = 0.068, Bon = 0.748). These different impacts of MGMT status on OS were similar in newly diagnosed GBM patients, elderly GBM patients and recurrent GBM. Among patients receiving TMZ-free treatment, survival benefit in Asian patients was not observed anymore after Bonferroni correction (Asian OS: HR = 0.78, 95% CI 0.64-0.95, p = 0.02, Bon = 0.24, I2 = 0%; PFS: HR = 0.69, 95% CI 0.50-0.94, p = 0.02, Bon = 0.24). No benefit was observed in Caucasian receiving TMZ-free therapy regardless of Bonferroni adjustment. CONCLUSION: The meta-analysis highlights the universal predictive value of MGMT methylation in newly diagnosed GBM patients, elderly GBM patients and recurrent GBM patients. For elderly methylated GBM patients, TMZ alone therapy might be a more suitable option than radiotherapy alone therapy. Future clinical trials should be designed in order to optimize therapeutics in different GBM subpopulation.

Activation of G-protein coupled estrogen receptor 1 improves early-onset cognitive impairment via PI3K/Akt pathway in rats with traumatic brain injury.

Previous studies experimentally reveal that G-protein coupled estrogen receptor 1(GPER) has neuroprotection against ischemic injury. However, its effect on traumatic brain injury (TBI) is less well-established. Cognitive impairment following human TBI is a common clinical observation, and TBI is considered as a risk factor for Alzheimer's disease (AD). This study aimed to observe the possible protective effect of GPER on early-onset cognitive impairment after a single TBI and investigate the cellular mechanism underlying its actions. We found that selective GPER agonist G-1 significantly reduced hippocampal CA1 neuronal loss and improved cognitive impairment in TBI rats. Although previous studies have shown that AD-like tau pathology occurs many years after both repetitive and single TBI, accumulation of hyperphosphorylated tau was not observed within days (detected at 24 h and 7d) after TBI. Furthermore, tau phosphorylation was not altered by G-1 treatment. It was found that G-1 administration caused an increase in p-Akt level. However, the neuroprotective effects of G-1 on spatial cognition and neuronal death were attenuated by PI3K/Akt inhibitor LY294002. These findings indicate that GPER agonist G-1 had protection on cognitive function via activation of PI3K/Akt signaling. Early-onset cognitive impairment following a single TBI was closely associated with acute hippocampal neuronal loss rather than tau pathology. This study suggests that early activation of GPER might be a promising therapeutic strategy for improvement of TBI-induced cognitive outcomes.

Overactivation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiates accumulation of hyperphosphorylated tau in rat hippocampus after transient middle cerebral artery occlusion.

Middle cerebral artery occlusion (MCAO) induces secondary damages in the hippocampus that is remote from primary ischemic regions. Tau hyperphosphorylation is an important risk for neurodegenerative diseases. Increased tau phosphorylation has been identified in ischemic cortex, but little is known regarding the changes in the hippocampus. We showed that unilateral transient MCAO induced accumulation of hyperphosphorylated tau and concurrent dephosphorylation of glycogen synthase kinase-3ß at Ser 9 in the ipsilateral hippocampus. These MCAO-induced changes were not reproduced when glutamatergic inputs from the entorhinal cortex to the hippocampus were transected; however, the changes were mimicked by intrahippocampal N-methyl-d-aspartate (NMDA) administration. Inhibition of NMDA receptor (NMDAR) subunit NR2B, but not NR2A activity in the hippocampus attenuated the accumulation of hyperphosphorylated tau and spatial cognitive impairment in MCAO rats. Together, our data suggest that overactivation of NR2B-containing NMDARs through entorhinal-hippocampal connection plays an important role in the accumulation of hyperphosphorylated tau in the hippocampus following MCAO. Glycogen synthase kinase-3ß is an important protein kinase involved in NMDARs-mediated tau hyperphosphorylation. This study indicates that early inhibition of NR2B-containing NMDARs may represent a potential strategy to prevent or delay the occurrence of post-stroke dementia. Middle cerebral artery occlusion induces secondary damage in the hippocampus that is remote from primary ischemic regions. We propose that excessive activation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiated the accumulation of hyperphosphorylated tau in the hippocampus, which subsequently induced cognitive deficit. This study provides new insights into the prospects of NR2B inhibition in stoke therapy.

Involvement of ROS-alpha v beta 3 integrin-FAK/Pyk2 in the inhibitory effect of melatonin on U251 glioma cell migration and invasion under hypoxia.

BACKGROUND: Melatonin, a well-known antioxidant, has been shown to possess anti-invasive properties for glioma. However, little is known about the effect of melatonin on glioma cell migration and invasion under hypoxia, which is a crucial microenvironment for tumor progress. In addition, focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2) are closely associated with cell migration and invasion. Therefore, we investigated the possible role of these kinases and its related signaling in the regulation of human U251 glioma cells behavior by melatonin under hypoxia. METHODS: The abilities of migration and invasion of U251 glioma cells were determined by wound healing and transwell assay in vitro. The intracellular production of reactive oxygen species (ROS) was measured by using the fluorescent probe 6-carboxy-2', 7'-dichorodihydrofluorescein diacetate (DCFH-DA). Immunofluorescence experiments and western blotting analysis were used to detect the expression level of protein. Small interfering RNAs (siRNA) was used to silence specific gene expression. RESULTS: The pharmacologic concentration (1 mM) of melatonin significantly inhibited the migration and invasion of human U251 glioma cells under hypoxia. The inhibitory effect of melatonin was accompanied with the reduced phosphorylation of FAK and Pyk2, and decreased expression of alpha v beta 3 (αvß3) integrin. Additionally, inhibition of αvß3 integrin by siRNA reduced the phosphorylation of FAK/Pyk2 and demonstrated the similar anti-tumor effects as melatonin, suggesting the involvement of αvß3 integrin- FAK/Pyk2 pathway in the anti-migratory and anti-invasive effect of melatonin. It was also found that melatonin treatment decreased the ROS levels in U251 glioma cells cultured under hypoxia. ROS inhibitor apocynin not only inhibited αvß3 integrin expression and the phosphorylation levels of FAK and Pyk2, but also suppressed the migratory and invasive capacity of U251 glioma cells under hypoxia. CONCLUSIONS: These results suggest that melatonin exerts anti-migratory and anti-invasive effects on glioma cells in response to hypoxia via ROS-αvß3 integrin-FAK/Pyk2 signaling pathways. This provides evidence that melatonin may be a potential therapeutic molecule targeting the hypoxic microenvironment of glioma.

Induction of proline-rich tyrosine kinase 2 activation-mediated C6 glioma cell invasion after anti-vascular endothelial growth factor therapy.

BACKGROUND: Anti-angiogenic therapy inhibits tumor growth and is considered as a potential clinical therapy for malignant glioma. However, inevitable recurrences and unexpected tumor resistance, particularly increased invasion ability of glioma cell, were observed after anti-angiogenic treatment. The underlying mechanism remains undetermined. Focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (Pyk2) are closely associated with cell migration; therefore, we investigated the possible role of these kinases in rat C6 glioma cell invasion induced by bevacizumab, a recombinant monoclonal antibody against vascular endothelial growth factor (VEGF). METHODS: The effects of bevacizumab on migration and invasion of C6 glioma cells were investigated in vitro and in vivo. The cells proliferation, migration, and invasion were determined by MTT assay, wound healing, and transwell assay, respectively. Invasive potential of glioma cells in vivo was assessed by counting vimentin-positive cells crossing the solid tumor rim by immunohistochemical staining. The total and phosphorylated protein levels of FAK and Pyk2 were detected by Western blotting. RESULTS: Bevacizumab exposure increased migration and invasion of cultured C6 cells in a concentration-dependent manner. In addition, the continuous bevacizumab treatment also promoted tumor invasion in rat C6 intracranial glioma models. Bevacizumab treatment enhanced Pyk2 phosphorylation at Tyr402, but no effect on FAK phosphorylation at Tyr397 both in vitro and in vivo. Knockdown of Pyk2 by siRNA or inhibition of Pyk2 phosphorylation by Src kinase specific inhibitor PP1 partially inhibited bevacizumab-induced cell invasion in cultured C6 glioma cells. Furthermore, the combined administration of bevacizumab and PP1 significantly suppressed glioma cell invasion into surrounding brain tissues compared to bevacizumab treatment alone in experimental rats. CONCLUSIONS: These results suggest that anti-VEGF treatment promotes glioma cell invasion via activation of Pyk2. Inhibition of Pyk2 phosphorylation might be a potential target to ameliorate the therapeutic efficiency of anti-VEGF treatment.

Delta-like ligand 4 correlates with endothelial proliferation and vessel maturation in human malignant glioma.

AIM: To investigate the role of delta-like ligand 4 (DLL4) in the angiogenesis of high-grade malignant glioma. MATERIALS AND METHODS: DLL4 expression and microvessel density (MVD) were detected by immunohistochemistry in 51 human high-grade malignant glioma tissue samples. The vessel maturation index (VMI) was calculated as the percentage of a-smooth muscle actin (a-SMA)-positive vessels in relation to the amount of CD31-positive vessels. Double fluorescent immunostaining for CD31 and EphrinB2 or EphB4 was performed to identify the arterial (EphrinB2) or venous (EphB4) origins of glioma microvessels. RESULTS: Strong immunostaining of DLL4 and a positive correlation of DLL4 with the MVD were observed in high-grade malignant gliomas. The VMI of the DLL4-positive group was significantly higher than that of the DLL4-negative group. However, no significant association was found between DLL4 and EphrinB2 or EphB4 in high-grade gliomas. CONCLUSION: DLL4 may be an important regulator for vessel proliferation and maturation in human high-grade malignant gliomas.