Circular RNA circ_0079593 facilitates glioma development via modulating miR-324-5p/XBP1 axis.

Glioma is a common brain tumor with high mortality. Circular RNAs (circRNAs) play crucial roles in tumor occurrence and development. However, the function and molecular basis of circ_0079593 in glioma remain unknown. Quantitative real-time PCR (qPCR) and Western blot were used for expression determination of circ_0079593, microRNA-324-5p (miR-324-5p) and X-box binding protein 1 (XBP1). Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, transwell assays, and tube formation assay were employed to evaluate cell functions. Glycolysis was determined via detecting glucose consumption, lactate production and ATP level. The binding relationship between miR-324-5p and circ_0079593 or XBP1 was validated by dual-luciferase reporter assay and RNA Immunoprecipitation (RIP) assay. Besides, xenograft assay was applied to test tumor growth in vivo. Circ_0079593 and XBP1 levels were elevated, while miR-324-5p level was declined in glioma. Silencing of circ_0079593 restrained proliferation, mobility, angiogenesis and glycolysis and induced apoptosis in glioma cells. Circ_0079593 accelerated glioma progression via sequestering miR-324-5p, one of the targets of circ_0079593. XBP1 was a target gene of miR-324-5p, and miR-324-5p alleviated the malignant growth of glioma by repressing XBP1. Furthermore, silence of circ_0079593 hindered tumor growth in vivo. Circ_0079593 contributed to the malignant evolution of glioma via modulating miR-324-5p and downstream XBP1 gene, suggesting that circ_0079593 might be a promising therapeutic target for glioma. Circ_0079593 was boosted in glioma. Circ_0079593 depletion restrained glioma progression. Circ_0079593 triggered glioma development via miR-324-5p/XBP1 axis. Circ_0079593 silence suppressed glioma tumorigenesis in vivo.

Role of Peroxiredoxin 2 in the Protection Against Ferrous Sulfate-Induced Oxidative and Inflammatory Injury in PC12 Cells.

Peroxiredoxin 2 (Prdx2) is a ubiquitous antioxidant enzyme in mammalian brain. Although a protective role of Prdx2 has been established in cerebral ischemia and several neurodegenerative diseases, its contribution against iron-induced neurocytotoxicity still remains to be determined. Accordingly, in this study, we aimed to investigate the effects of Prdx2 on iron-induced cytotoxicity using an in vitro model in which PC12 cells are exposed to ferrous sulfate (FS). The FS treatment increased Prdx2 expression, and promoted lactate dehydrogenase (LDH) release and cell apoptosis in PC12 cells, accompanied by the increase in the Bax/Bcl2 ratio, cytochrome c release, and caspase-3 cleavage. FS exposure also increased the malondialdehyde content (lipid peroxidation), 3'-nitrotyrosine expression (protein nitration), γ-H2A.X formation (DNA oxidation), and promoted nuclear factor kappa B nuclear translocation, cyclooxygenase-2 expression, and release of tumor necrosis factor-α and interleukin-1ß. Lentivirus-mediated Prdx2 knockdown intensified the FS-induced LDH release and cell apoptosis by aggravating the oxidative and inflammatory damage. In conclusion, our findings demonstrated that Prdx2 played a vital role in the protection against iron-induced cytotoxicity in PC12 cells.

Nuclear factor-κB activation in perihematomal brain tissue correlates with outcome in patients with intracerebral hemorrhage.

BACKGROUND: Nuclear factor-κB (NF-κB) plays an important role in the inflammatory response after intracerebral hemorrhage (ICH). We therefore proposed that NF-κB activation in perihematomal brain tissue might correlate with clinical outcome in patients with ICH. To confirm this, we studied clinical data of 45 patients with ICH and NF-κB activation in perihematomal brain tissue and analyzed predictors of clinical outcome as well as the predictive value of NF-κB activation. METHODS: Forty-five patients with spontaneous basal ganglia hemorrhage were prospectively investigated. The clinical data were collected, which include demographics, alcohol and tobacco abuse, stroke risk factors, neuroimaging variables at presentation, Glasgow Coma Scale (GCS) at admission, number of days in hospital, mechanical ventilation, pneumonia, and outcome. Clinical outcome was assessed by the modified Rankin Scale at 6 months after ICH. Perihematomal brain tissue was collected, and NF-κB activation was detected using immunohistochemistry. Univariate analysis and multivariate logistic regression analysis were performed to determine predictors of the poor outcome. RESULTS: Immunohistochemical detection showed that NF-κB p65 was expressed in the nuclei of neurons and glial cells in all patients. The number of nuclear NF-κB p65-positive cells was 54 ± 21. Six months after ICH, 18 (40%) patients achieved a favorable functional outcome (mRS ≤ 3) while 27 (60%) had a poor functional outcome (mRS 4 to 6). In univariate analysis, predictors of poor functional outcome were lower GCS score on admission (P = 0.004), larger hematoma volume (P = 0.004), intraventricular extension (P = 0.047), midline shift (P = 0.005), NF-κB activation (P < 0.0001), mechanical ventilation (P = 0.018), and co-morbidity with pneumonia (P = 0.002). In multivariate logistic regression analysis, NF-κB activation was the only independent predictor of poor outcome at 6 months after ICH. CONCLUSIONS: NF-κB activation is closely related to clinical outcome 6 months after ICH in humans. Therefore, it could be useful to predict prognosis of ICH accurately and should be further evaluated as a target for therapeutic strategies of ICH in the future.

MiR-7-5p is frequently downregulated in glioblastoma microvasculature and inhibits vascular endothelial cell proliferation by targeting RAF1.

The aberrant expression of microRNAs (miRNAs) is always associated with tumor development and progression. Microvascular proliferation is one of the unique pathologic features of glioblastoma (GBM) . In this study, the microvasculature from GBM or normal brain tissue derived from neurosurgeries was purified and total RNA was isolated from purified microvasculature. The difference of miRNA expression profiles between glioblastoma microvasculature and normal brain capillaries was investigated. It was found that miR-7-5p in GBM microvessels was significantly reduced compared with that in normal brain capillaries. In the in vitro experiments, overexpression of miR-7-5p significantly inhibited human umbilical vein endothelial cell proliferation. Forced expression of miR-7-5p in human umbilical vein endothelial cells in vitro significantly reduced the protein level of RAF1 and repressed the activity of the luciferase, a reporter vector carrying the 3'-untranslated region of RAF1. These findings indicate that RAF1 is one of the miR-7-5p target genes. Furthermore, a significant inverse correlation between miR-7-5p expression and RAF1 protein level in GBM microvasculature was found. These data suggest that miR-7-5p functions as a tumor suppressor gene to regulate GBM microvascular endothelial cell proliferation potentially by targeting the RAF1 oncogene, implicating an important role for miR-7-5p in the pathogenesis of GBM. It may serve as a guide for the antitumor angiogenesis drug development.

Inhibiting nuclear factor-κB at different stages after intracerebral hemorrhage can influence the hemorrhage-induced brain injury in experimental models in vivo.

OBJECTIVE: Nuclear factor-κB (NF-κB) is a critical regulator of inflammatory responses after ICH, and different subunits may have different influences on the cell death and prognosis. The aim of the present study is to clarify whether the prognosis can be influenced by inhibiting NF-κB activation and subunits expression using PDTC at different stages after ICH. METHODS: Rats were divided into sham group, ICH group, early interference group and late interference group. At preset time points after ICH, the ipsilateral striatum and tissue around was obtained for detection of NF-κB activation, cell death, and expression of caspase-3, bcl-2, and NF-κB subunits, to evaluate of the effect of PDTC. RESULTS: NF-κB subunit p65 mainly expressed at the early stage after ICH, and c-Rel at the late stage. NF-κB activation can be inhibited at the early stage after ICH by administrating PDTC at 10 min, 1d and 2d after ICH, and at the late stage at 6d,7d and 8d. NF-κB activation inhibition at the early stage was due to p65, and c-Rel at the late stage. Inhibiting p65 expression at the early stage after ICH can reduce the apoptotic factor caspase-3 expression and cell death, and raise the antiapoptotic factor bcl-2. Meanwhile, inhibiting c-Rel expression at the late stage after ICH can lead to the opposite result. CONCLUSION: Measures of inhibiting NF-κB subunits can be performed to influence the secondary brain damage and prognosis of ICH. We can also speculate that early inhibition of p65 expression and late promotion of c-Rel expression may be a more efficient method to improve the prognosis of ICH.

Separate administration of ammonium pyrrolidinedithiocarbamate and phorbol myristate acetate at early and late stages decreases secondary brain injury following intracerebral haemorrhage in rats via the NF-κB pathway.

INTRODUCTION: Nuclear factor-kB (NF-kB) is a critical regulator of inflammatory responses following intracerebral haemorrhage (ICH). According to our previous study, inhibiting the p65 subunit at an early stage after ICH can reduce cell death, while inhibiting c-Rel at a late stage can lead to the opposite result. The aim of this study is to clarify whether patient prognosis can be improved by inhibiting p65 at the early stage and promoting c-Rel at the late stage. MATERIAL AND METHODS: Rats were divided into a sham group, ICH group, early NF-kB-inhibiting group using ammonium pyrrolidinedithiocarbamate (PDTC; group A, p65 subunit was dominant and inhibited at the early stage), late NF-kB-activating group using phorbol myristate acetate (PMA; group B, c-Rel was dominant and promoted at the late stage), and early NF-kB-inhibiting and late-activating group (group C, p65 subunit was inhibited at the early stage and c-Rel was promoted at the late stage). At preset time points after ICH, perihematomal tissue was obtained for detection of NF-kB activation, cell death, and expression of caspase-3, Bcl-2, and NF-kB subunits, to evaluate of the effect of PDTC and PMA. RESULTS: At four days after ICH, p65 expression (p < 0.01) and the number of TUNEL-positive cells (p < 0.01) in group A were significantly lower than in the ICH group. At 10 days after ICH, c-Rel expression in groups B and C was significantly higher than in other groups (p < 0.01 for all). TUNEL-positive cell numbers in groups A and B were significantly lower than in the ICH group, though more numerous than in group C (p < 0.01 for all). CONCLUSIONS: Administration of both PDTC at the early stage and PMA at the late stage reduced perihematomal cell death after ICH, and using the two reagents together had a stronger anti-apoptotic effect than separate usage.

High-Throughput Sequencing-Based Identification of Serum Exosomal Differential miRNAs in High-Grade Glioma and Intracranial Lymphoma.

OBJECTIVE: At present, no effective noninvasive method is currently available for the differential diagnosis of high-grade glioma and intracranial lymphoma. In the present study, we aimed to screen microRNA (miRNA) markers in serum exosomes for differential diagnosis of high-grade glioma and intracranial lymphoma using high-throughput sequencing technology. METHODS: Patients with intracranial lymphoma or high-grade glioma and healthy controls were included in this study (training cohort (n = 10) and validation cohort: intracranial lymphoma (n = 10), high-grade glioma (n = 32), and healthy controls (n = 20)). After RNA was extracted from serum exosomes, the high-throughput sequencing was used to determine the expression profiles of serum exosomal miRNAs and screen the differentially expressed miRNAs. RT-qPCR was used to verify the expressions of the selected miRNAs. The differences of miRNA expressions between groups were assessed by the Kruskal-Wallis test. The diagnostic value was analyzed using the receiver operating characteristic (ROC) curve. RESULTS: High-throughput sequencing demonstrated that 170 miRNAs, including 109 upregulated ones and 61 downregulated ones, were differentially expressed in serum exosomes between the patients with intracranial lymphoma and high-grade glioma. Compared with the healthy controls, the number of differential serum exosomal miRNAs in the high-grade glioma group and intracranial lymphoma group was 130 and 173, respectively. RT-qPCR proved that both miR-766-5p and miR-376b-5p were significantly downregulated in high-grade glioma and intracranial lymphoma patients compared with the healthy controls (all p < 0.001), and the expression of serum exosomal miR-766-5p in the intracranial lymphoma group was lower compared with the high-grade glioma group (p < 0.05). The areas under ROC curve (AUCs) of serum exosomal miR-766-5p and miR-376b-5p for the diagnosis of glioma were 0.8883 (p < 0.001) and 0.7688 (p = 0.001), respectively, and they were 0.9271 (p < 0.001) and 0.8542 (p < 0.001), respectively, for the diagnosis of intracranial lymphoma. Moreover, the AUC value of serum exosomal miR-766-5p for the differential diagnosis of glioma and intracranial lymphoma was 0.7201 (p = 0.026). CONCLUSIONS: miR-766-5p and miR-376b-5p in serum exosomes might be used as auxiliary diagnostic indicators for high-grade glioma and intracranial lymphoma, and miR-766-5p might be used as a differential diagnostic marker for both diseases.

Inhibition of Drp1 after traumatic brain injury provides brain protection and improves behavioral performance in rats.

The imbalance between mitochondrial fusion and fission has been implicated in cerebral ischemia and several neurodegenerative diseases. However, the role of mitochondrial fission in traumatic brain injury (TBI) remains poorly understood. Mitochondrial fission is mediated by dynamin-related protein 1 (Drp1), which is highly expressed in the nervous system. In the present study, we investigated the changes in Drp1 expression in the ipsilateral hippocampus of rats after TBI and the effects of Mdivi-1 (a selective inhibitor of Drp1) as a post-insult treatment for TBI. Our findings showed that the protein levels of Drp1 were increased at 6 h and peaked at 12 h post-TBI, but we did not observe Drp1 phosphorylation at Ser616, Ser637, Ser40 or Ser44 during this process. We examined the effect of Mdivi-1 on trauma-induced brain damage in both vitro and vivo. In cells, Mdivi-1 significantly attenuated H2O2-induced mitochondrial membrane potential (MMP) dissipation in PC-12 cells. Three days of Mdivi-1 treatment significantly reduced the cortical lesion volume, blood-brain barrier permeability, brain edema and oxidative stress. Mdivi-1 reduced activated caspase-3 release in the cortical border zone and hippocampal dentate gyrus three days after TBI. Furthermore, treatment with Mdivi-1 for 4 weeks rescued neurogenesis in DG and attenuated hippocampal atrophy. Regarding behavioral outcomes, Mdivi-1-treated TBI rats showed a significant improvement in water maze acquisition and retention compared with the saline-treated TBI rats. Moreover, Mdivi-1 treatment reduced anxiety-like behavior in an open-field test. Our results support the notion that Mdivi-1 provides brain protection and improves the behavioral performance in TBI rats.

Tripartite motif-containing protein 37 is overexpressed in human glioma and its downregulation inhibits human glioma cell growth in vitro.

Glioma is one of the most malignant tumor types worldwide. Despite great efforts made in surgery, imaging, chemotherapy, and radiation, the overall prognosis for patients with glioma remains poor. The pathogenesis of glioma is an urgent problem that must be solved. Tripartite motif-containing protein 37 (TRIM37) is an E3 ubiquitin ligase that may be involved in the tumorigenesis of several types of cancer; however, its expression pattern and biological functions in glioma remain unknown. Our previous studies indicated that the expression levels of TRIM37 were upregulated in glioma samples and were associated with a higher glioma grade. The present study demonstrates that suppression of TRIM37 by RNA-mediated interference inhibits the growth of glioma cells in vitro, which is associated with induction of apoptosis and cell cycle arrest, and with inhibition of migration and invasion. These results provide insights into understanding the role of TRIM37 in regulating the biological behavior of glioma cells and may indicate TRIM37 as a candidate target for the treatment of glioma.

Tert-butylhydroquinone protects PC12 cells against ferrous sulfate-induced oxidative and inflammatory injury via the Nrf2/ARE pathway.

Increasing evidence had proved the critical role of iron in the pathogenesis of numerous neurodegenerative diseases because of its capacity to promote the formation of reactive oxygen species (ROS). Tert-butylhydroquinone (tBHQ) was a metabolite of butylated hydroxyanisole, a widely used food antioxidant. This study was aimed to investigate the protective effects of tBHQ on a cellular model of neurodegenerative disease, which was established in PC12 cells by exposure to ferrous sulfate (FS), and elucidate the potential protective mechanisms. The results showed that FS exposure increased lactate dehydrogenase (LDH) release and cell apoptosis in PC12 cells, accompanied by significant increases in the bax/bcl-2 ratio, cytochrome c release, and caspase-3 cleavage. It also enhanced the ROS production, malondialdehyde (MDA) content (lipid peroxidation), γ-H2A.X formation (DNA damage), and promoted nuclear factor kappa B (NF-κB) activation and expressions of cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). tBHQ pretreatment alleviated FS-induced LDH release, cell apoptosis, oxidative stress and inflammatory response by promoting Nrf2 nuclear translocation and the protein levels of Nrf2 downstream target genes heme oxygenase-1 (Hmox-1), nicotinamide adenine dinucleotide phosphate (NADPH): quinone oxidoreductase-1 (Nqo1) and glutathione peroxidase-1 (Gpx1). tBHQ alleviated the FS-induced LDH release in control siRNA-treated PC12 cells, but failed to alleviate FS-induced LDH release in Nrf2 siRNA-treated cells. These findings suggested that pretreatment with tBHQ protected PC12 cells from FS-induced oxidative and inflammatory injury via the Nrf2/ARE pathway. tBHQ was promising as a potential therapeutic agent for neurodegenerative diseases induced by iron toxicity and should be encouraged for further research.

Preoperative albumin-to-globulin ratio and prognostic nutrition index predict prognosis for glioblastoma.

OBJECTIVE: Impaired immunonutritional status has disadvantageous effects on outcomes for cancer patients. Preoperative albumin-to-globulin ratio (AGR) and the prognostic nutrition index (PNI) have been used as prognostic factors in various cancers. We aimed to evaluate the clinical significance of the AGR and PNI in glioblastoma. MATERIALS AND METHODS: This retrospective analysis involved 166 patients. Demographic, clinical, and laboratory data were collected. AGR and the PNI were calculated as AGR = albumin/(total serum protein - albumin) and PNI = albumin (g/L) + 5 × total lymphocyte count (109/L). Overall survival (OS) was estimated by Kaplan-Meier analysis. Receiver-operating characteristic analysis was used to assess the predictive ability of AGR and the PNI. Cox proportional-hazard models estimating hazard ratios (HRs) and 95% confidence intervals (CIs) were used for univariable and multivariable survival analyses. RESULTS: The cutoff values of AGR and PNI were 1.75 and 48. OS was enhanced, with high AGR (>1.75) and the PNI (>48) (P<0.001 for both). Areas under the receiver-operating characteristic curve for AGR and the PNI were 0.68 and 0.631 for 1-year survival and 0.651 and 0.656 for 2-year survival (P<0.05 for all), respectively. On multivariable analyses, both AGR and the PNI were independent predictors of OS (AGR, HR 0.785, 95% CI 0.357-0.979 [P=0.04]; PNI, HR 0.757, 95% CI 0.378-0.985 [P=0.039]). On subgroup analysis, AGR and the PNI were significant prognostic factors for OS in patients with adjuvant therapy (AGR P<0.001; PNI P=0.001). CONCLUSION: Preoperative AGR and the PNI may be easy-to-perform and inexpensive indices for predicting OS with glioblastoma. AGR and the PNI could also help in developing good adjuvant-therapy schedules.

MicroRNA-27b inhibition promotes Nrf2/ARE pathway activation and alleviates intracerebral hemorrhage-induced brain injury.

Oxidative stress and neuroinflammation are the key factors leading to secondary brain injury after intracerebral hemorrhage (ICH). We investigated the effects of miR-27b, an oxidative stress-responsive microRNA, on ICH-induced brain injury in rats. The ICH model was induced by intracerebral injection of collagenase. Following ICH, miR-27b expression in the striatum was reduced, whereas expression of Nrf2 mRNA and protein was increased. In PC12 cells, overexpression of miR-27b reduced expression of Nrf2, Hmox1, Sod1 and Nqo1, while miR-27b inhibition had the opposite effects. Dual luciferase reporter assays showed that Nrf2 mRNA was a direct target of miR-27b. Intracerebroventricular injection of miR-27b antagomir and transfection of miR-27b inhibitor inhibited endogenous miR-27b in rats and PC12 cells, respectively. MiR-27b antagomir promoted activation of the ICH-induced Nrf2/ARE pathway and reduced the lipid peroxidation, neuroinflammation, cell death and neurological deficits otherwise seen after ICH. In PC12 cells, the miR-27b inhibitor diminished iron-induced oxidative stress, inflammation and apoptosis, and those effects were blocked by Nrf2 knockdown. These results demonstrate that miR-27b inhibition alleviates ICH-induced brain injury, which may be explained in part by its regulation on the Nrf2/ARE pathway.

Blockade of store-operated calcium entry alleviates high glucose-induced neurotoxicity via inhibiting apoptosis in rat neurons.

Altered store-operated calcium entry (SOCE) has been suggested to be involved in many diabetic complications. However, the association of altered SOCE and diabetic neuronal damage remains unclear. This study aimed to investigate the effects of altered SOCE on primary cultured rat neuron injury induced by high glucose. Our data demonstrated that high glucose increased rat neuron injury and upregulated the expression of store-operated calcium channel (SOC). Inhibition of SOCE by a pharmacological inhibitor and siRNA knockdown of stromal interaction molecule 1 weakened the intracellular calcium overload, restored mitochondrial membrane potential, downregulated cytochrome C release and inhibited cell apoptosis. As well, treatment with the calcium chelator BAPTA-AM prevented cell apoptosis by ameliorating the high glucose-increased intracellular calcium level. These findings suggest that SOCE blockade may alleviate high glucose-induced neuronal damage by inhibiting apoptosis. SOCE might be a promising therapeutic target in diabetic neurotoxicity.

The diagnostic value and functional roles of phosphoglycerate mutase 1 in glioma.

Previous studies indicated that phosphoglycerate mutase 1 (PGAM1) is involved in many cancer types and promotes breast cancer progression. However, the role of PGAM1 in glioma remains unclear. The present study aimed to investigate the association of PGAM1 expression with glioma grade and the role of PGAM1 in proliferation, apoptosis, migration and invasion of glioma cells. The mRNA and protein expression of PGAM1 was analysed in glioma tissues and normal brain tissues. The expression of PGAM1 was examined further by immunohistochemical analysis. In addition, we inhibited the expression of PGAM1 in glioma cell line by siRNA to evaluate its role in glioma proliferation, apoptosis, migration and invasion. The mRNA and protein expression of PGAM1 was significantly greater in glioma than normal brain tissues. PGAM1 expression was associated with the WHO grade of glioma. siRNA knockdown of PGAM1 significantly inhibited glioma cell proliferation, promoted glioma cell apoptosis, induced S phase cell cycle arrest and inhibited glioma cell migration and invasion in vitro. PGAM1 may be associated with the grade of glioma and be involved in the biological behavior of glioma cells. PGAM1 might be a novel therapeutic target in glioma.