CircRNF10 triggers a positive feedback loop to facilitate progression of glioblastoma via redeploying the ferroptosis defense in GSCs.

BACKGROUND: Glioma exhibit heterogeneous susceptibility for targeted ferroptosis. How circRNAs alterations in glioma promote iron metabolism and ferroptosis defense remains unclarified. METHODS: The highly enriched circRNAs in glioblastoma (GBM) were obtained through analysis of sequencing datasets. Quantitative real-time PCR (qRT-PCR) was used to determine the expression of circRNF10 in glioma and normal brain tissue. Both gain-of-function and loss-of-function studies were used to assess the effects of circRNF10 on ferroptosis using in vitro and in vivo assays. The hypothesis that ZBTB48 promotes ferroptosis defense was established using bioinformatics analysis and functional assays. RNA pull-down and RNA immunoprecipitation (RIP) assays were performed to examine the interaction between circRNF10 and target proteins including ZBTB48, MKRN3 and IGF2BP3. The posttranslational modification mechanism of ZBTB48 was verified using coimmunoprecipitation (co-IP) and ubiquitination assays. The transcription activation of HSPB1 and IGF2BP3 by ZBTB48 was confirmed through luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays. The stabilizing effect of IGF2BP3 on circRNF10 was explored by actinomycin D assay. Finally, a series of in vivo experiments were performed to explore the influences of circRNF10 on the glioma progression. RESULTS: A novel circular RNA, hsa_circ_0028912 (named circRNF10), which is significantly upregulated in glioblastoma tissues and correlated with patients' poor prognosis. Through integrated analysis of the circRNA-proteins interaction datasets and sequencing results, we reveal ZBTB48 as a transcriptional factor binding with circRNF10, notably promoting upregulation of HSPB1 and IGF2BP3 expression to remodel iron metabolism and facilitates the launch of a circRNF10/ZBTB48/IGF2BP3 positive feedback loop in GSCs. Additionally, circRNF10 can competitively bind to MKRN3 and block E3 ubiquitin ligase activity to enhance ZBTB48 expression. Consequently, circRNF10-overexpressed glioma stem cells (GSCs) display lower Fe2+ accumulation, selectively priming tumors for ferroptosis evading. CONCLUSION: Our research presents abnormal circRNAs expression causing a molecular and metabolic change of glioma, which we leverage to discover a therapeutically exploitable vulnerability to target ferroptosis.

The critical roles of lnc-GLYATL2-2/PD-L1 axis in immune microenvironment and the clinical value of intracranial chordomas.

Intracranial chordomas (ICs) are associated with a poor prognosis due to low total resection rates and high recurrence rates. However, the role of immunotherapy in ICs remains unknown. RNA sequencing and immunohistochemical staining were performed on IC tissues and normal tissues, and the long noncoding RNA (lncRNA) lnc-GLYATL2-2 was identified. The results indicated that high expression of lnc-GLYATL2-2 was positively correlated with the tumor-infiltrating lymphocyte (TIL) markers CD4 and Foxp3, negatively correlated with CD8, and positively correlated with the expression of the immune checkpoint molecules programmed death receptor-1 (PD-1) and programmed death ligand 1 (PD-L1). Additionally, Kaplan-Meier and univariate or multivariate Cox regression analyses revealed the predictive value of lnc-GLYATL2-2 for survival based on clinical data from patients with ICs. A high expression level of lnc-GLYATL2-2 is potentially correlated with a suppressive tumor immune microenvironment and adverse clinical outcomes in IC patients. Mechanistically, the upregulation of lnc-GLYATL2-2 can result in increased cytoplasmic levels of ELAVL1, leading to enhanced binding to the 3'-UTR of PD-L1 mRNA and maintenance of its stability. In contrast, lnc-GLYATL2-2 can directly interact with the PD-L1 protein to prevent degradation, thereby promoting high levels of PD-L1 expression simultaneously at the transcriptional and translational levels in chordoma cells. These results provide a new perspective on the diagnosis and prognosis of ICs and provide theoretical evidence for immunotherapy in patients with ICs.

Circular RNA circPTPRF promotes the progression of GBM via sponging miR-1208 to up-regulate YY1.

Glioblastoma (GBM) is the most common primary malignant tumor in the brain, and its robust proliferation and invasion abilities reduce the survival time of patients. Circular RNAs (circRNAs) play an essential role in various tumors, such as regulating tumor cell proliferation, apoptosis, invasion, metastasis, and other progressive phenotypes through different mechanisms. Finding novel circRNAs may significantly contribute to the prognosis of GBM and provide the basis for the targeted therapy of GBM. In this study, we found circPTPRF is a novel circRNA that has never been studied, which was highly expressed in GBM and is closely related to poor patient prognoses. After knockdown or overexpression in glioma cell lines (U87 and LN229) and glioma stem cells (GSCs), we identified that circPTPRF could promote proliferation, invasion, and neurospheres formation abilities of GBM via in vitro and in vivo experiments. Mechanisms, miR-1208 was confirmed as a target of circPTPRF, and miR-1208 can also target the 3'UTR of YY1, and they were proved by luciferase reporter, western blotting (WB), qPCR and RNA immunoprecipitation (RIP) assays. The following rescue experiments demonstrated that circPTPRF was a miR-1208 sponge for upregulating YY1 expression to promote proliferation, invasion and neurosphere formation abilities of GBM in vitro. In conclusion, the circPTPRF/miR-1208/YY1 axis can regulate GBM progression. CircPTPRF may play an essential role in GBM diagnosis and prognostic prediction and be an important molecular target for GBM therapy.

CircLRFN5 inhibits the progression of glioblastoma via PRRX2/GCH1 mediated ferroptosis.

BACKGROUND: Ferroptosis is a novel form of iron-dependent cell death and participates in the malignant progression of glioblastoma (GBM). Although circular RNAs (circRNAs) are found to play key roles in ferroptosis via several mechanisms, including regulating iron metabolism, glutathione metabolism, lipid peroxidation and mitochondrial-related proteins, there are many novel circRNAs regulating ferroptosis need to be found, and they may become a new molecular treatment target in GBM. METHODS: The expression levels of circLRFN5, PRRX2 and GCH1 were detected by qPCR, western blotting, and immunohistochemistry. Lentiviral-based infections were used to overexpress or knockdown these molecules in glioma stem cells (GSCs). The biological functions of these molecules on GSCs were detected by MTS (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium), the 5-ethynyl-20-deoxyuridine (EdU) incorporation assay, transwell, neurosphere formation assays, Extreme Limiting Dilution Analysis (ELDA) and xenograft experiments. The content of ferroptosis levels in GSCs was detected by BODIPY 581/591 C11 assay, glutathione (GSH) assay and malondialdehyde (MDA) assay. The regulating mechanisms among these molecules were studied by RNA immunoprecipitation assay, RNA pull-down assay, ubiquitination assay, dual-luciferase reporter assay and chromatin immunoprecipitation assay. RESULTS: We found a novel circRNA circLRFN5 is downregulated in GBM and associated with GBM patients' poor prognosis. CircLRFN5 overexpression inhibits the cell viabilities, proliferation, neurospheres formation, stemness and tumorigenesis of GSCs via inducing ferroptosis. Mechanistically, circLRFN5 binds to PRRX2 protein and promotes its degradation via a ubiquitin-mediated proteasomal pathway. PRRX2 can transcriptionally upregulate GCH1 expression in GSCs, which is a ferroptosis suppressor via generating the antioxidant tetrahydrobiopterin (BH4). CONCLUSIONS: Our study found circLRFN5 as a tumor-suppressive circRNA and identified its role in the progression of ferroptosis and GBM. CircLRFN5 can be used as a potential GBM biomarker and become a target for molecular therapies or ferroptosis-dependent therapy in GBM.

MicroRNA-223 Attenuates Stretch-Injury-Induced Apoptosis in Brain Microvascular Endothelial Cells by Regulating RhoB Expression.

MiR-223 is a miRNA with important functions in apoptosis, carcinogenesis, and inflammation, and it was demonstrated to be over-expressed in brain tissue after traumatic brain injury (TBI). However, few studies have focused on its role in protecting brain microvascular endothelial cells (BMECs). This study evaluated the protective effect of miR-223 on BMECs after stretch injury (SI). bEnd.3 cells (BMECs of mouse) were transfected with overexpressing and blocking lentivirus of miR-223, then were subjected to SI. After immunofluorescence assay, it was demonstrated that miR-223 overexpression significantly rescued the SI-induced loss of ZO-1 (Zonula Occludens 1, tight junction protein) (p < 0.01), while miR-223 blocking exacerbated the loss of ZO-1 (p < 0.05). Flow cytometry confirmed a significant increase in the proportion of apoptotic bEnd.3 cells after SI, and miR-223 overexpression reduced this proportion (p < 0.001). The result of Western blot revealed that miR-223 overexpression significantly reduced the expression of cleaved caspase-3 (cl-caspase 3) (p < 0.05) and RhoB (p < 0.01), while miR-223 blocking increased the expression of these proteins (p < 0.05, p < 0.001). Additionally, knockdown of RhoB significantly reduced the expression of cl-caspase 3 (p < 0.001). These findings suggested that miR-223 can alleviate SI-induced apoptosis of BMECs, and this anti-apoptotic effect is at least partially achieved by inhibiting the expression of RhoB. Moreover, miR-223 may play a role in maintaining the integrity of BBB during TBI.

CircKPNB1 mediates a positive feedback loop and promotes the malignant phenotypes of GSCs via TNF-α/NF-κB signaling.

Glioma stem cells (GSCs) are a special kind of cells in GBM showing tumor initiation, self-renewal, and multi-lineage differentiation abilities. Finding novel circRNAs related to GSCs is of great significance for the study of glioma. qPCR, western blotting, and immunohistochemistry were used to detect the expression levels of circKPNB1, SPI1, DGCR8, and TNF-α. The expression of these molecules in GSCs was regulated by lentiviral-based infection. RNA immunoprecipitation assay, RNA pull-down, dual-luciferase reporter, and chromatin immunoprecipitation assays were used to study the direct regulation mechanisms among these molecules. All the MTS, EDU, transwell, neurosphere formation assays, ELDA assays, and xenograft experiments were used to detect the malignant phenotype of GSCs. We found a novel circRNA circKPNB1 was overexpressed in GBM and associated with GBM patients' poor prognosis. CircKPNB1 overexpression can promote the cell viabilities, proliferation, invasion, neurospheres formation abilities, and stemness of GSCs. Mechanistically, circKPNB1 regulates the protein stability and nuclear translocation of SPI1. SPI1 promotes the malignant phenotype of GSCs via TNF-α mediated NF-κB signaling. SPI1 can also transcriptionally upregulate DGCR8 expression, and the latter can maintain the stability of circKPNB1 and forms a positive feedback loop among DGCR8, circKPNB1 and SPI1. Our study found circKPNB1 was a novel oncogene in GBM and of great significance in the diagnosis and prognosis prediction of GBM and maybe a novel target for molecular targeted therapy.

Treatment of traumatic cerebrospinal fluid rhinorrhea via extended extradural anterior skull base approach.

OBJECTIVE: To describe and assess the repair technique and perioperative management for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture via extradural anterior skull base approach. METHODS: This was a retrospective review conducted at the Department of Neurosurgery of the Shanghai Tenth People's Hospital from January 2015 to April 2020. Patients with traumatic CSF rhinorrhea resulting from extensive anterior skull base fracture treated surgically via extended extradural anterior skull base approach were included in this study. The data of medical and radiological records, surgical approaches, repair techniques, peritoperative management, surgical outcome and postoperative follow-up were analyzed. Surgical repair techniques were tailored to the condition of associated injuries of the scalp, bony and dura injuries and associated intracranial lesions. Patients were followed up for the outcome of CSF leak and surgical complications. Data were presented as frequency and percent. RESULTS: Thirty-five patients were included in this series. The patients' mean age was 33 years (range 11-71 years). Eight patients were treated surgically within 2 weeks; while the other 27 patients, with prolonged or recurrent CSF rhinorrhea, received the repair surgery at 17 days to 10 years after the initial trauma. The mean overall length of follow-up was 23 months (range 3-65 months). All the patients suffered from frontobasal multiple fractures. The basic repair tenet was to achieve watertight seal of the dura. The frontal pericranial flap alone was used in 20 patients, combined with temporalis muscle and/or its facia in 10 patients. Free fascia lata graft was used instead in the rest 5 patients. No CSF leak was found in all the patients at discharge. There was no surgical mortality in this series. Bilateral anosmia was the most common complication. At follow-up, no recurrent CSF leak or meningitis occurred. No patients developed mucoceles, epidural abscess or osteomyelitis. One patient ultimately required ventriculoperitoneal shunt because of progressive hydrocephalus. CONCLUSION: Traumatic CSF rhinorrhea associated with extensive anterior skull base fractures often requires aggressive treatment via extended intracranial extradural approach. Vascularized tissue flaps are ideal grafts for cranial base reconstruction, either alone or in combination with temporalis muscle and its fascia---fascia lata sometimes can be opted as free autologous graft. The approach is usually reserved for patients with traumatic CSF rhinorrhea in complex frontobasal injuries.

Pharmacokinetics of colistin in cerebrospinal fluid after intraventricular administration alone in intracranial infections.

The aim of this study was to investigate the pharmacokinetics of colistin in cerebrospinal fluid (CSF) after intraventricular (IVT) administration of colistin methanesulfonate (CMS) for central nervous system (CNS) infections caused by multidrug-resistant Gram-negative bacteria. Ten patients with CNS infection were treated with CMS (active substance colistin equivalent to 100 000 units, every 24 h) by IVT administration. After 3 days of treatment, the concentration of colistin in the CSF was determined by selective ultra-performance liquid chromatography (UPLC) at 2, 4, 6, 8, 12 and 24 h after CMS administration. A pharmacokinetic analysis was performed using Phoenix WinNonlin. Following IVT administration of CMS, the estimated colistin apparent CSF half-life (t1/2) was 10.46 ± 6.98 h, the average peak colistin concentration (Cmax) was 16.95 ± 7.39 µg/mL and the average time to peak concentration (Tmax) was 4.6 ± 0.97 h. The measured trough concentration (Cmin; colistin concentration in CSF at 24 h after administration of CMS) was 1.12-8.33 µg/mL and the average Cmin was 2.91 ± 2.11 µg/mL. CSF concentrations of colistin were above the minimum inhibitory concentration (MIC) of 0.5 µg/mL at 24 h after IVT administration in all patients. Microbiological cure was observed in all patients. In conclusion, this is the first study of colistin pharmacokinetics in CSF after IVT administration alone in patients with CNS infection. It provides essential data for designing relatively safe and effective CMS dosing regimens.

Identification of key candidate genes and pathways in glioblastoma by integrated bioinformatical analysis.

Glioblastoma (GBM), characterized by high morbidity and mortality, is one of the most common lethal diseases worldwide. To identify the molecular mechanisms that contribute to the development of GBM, three cohort profile datasets (GSE50161, GSE90598 and GSE104291) were integrated and thoroughly analyzed; these datasets included 57 GBM cases and 22 cases of normal brain tissue. The current study identified differentially expressed genes (DEGs), and analyzed potential candidate genes and pathways. Additionally, a DEGs-associated protein-protein interaction (PPI) network was established for further investigation. Then, the hub genes associated with prognosis were identified using a Kaplan-Meier analysis based on The Cancer Genome Atlas database. Firstly, the current study identified 378 consistent DEGs (240 upregulated and 138 downregulated). Secondly, a cluster analysis of the DEGs was performed based on functions of the DEGs and signaling pathways were analyzed using the enrichment analysis tool on DAVID. Thirdly, 245 DEGs were identified using PPI network analysis. Among them, two co-expression modules comprising of 30 and 27 genes, respectively, and 35 hub genes were identified using Cytoscape MCODE. Finally, Kaplan-Meier analysis of the hub genes revealed that the increased expression of calcium-binding protein 1 (CABP1) was negatively associated with relapse-free survival. To summarize, all enriched Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways may participate in mechanisms underlying GBM occurrence and progression, however further studies are required. CABP1 may be a key gene associated with the biological process of GBM development and may be involved in a crucial mechanism of GBM progression.

The Most-Cited Works in Severe Traumatic Brain Injury: A Bibliometric Analysis of the 100 Most-Cited Articles.

BACKGROUND: There is an abundance of works published on severe traumatic brain injury (sTBI). Bibliometric analyses aim to provide a macroscopic view of research activities regarding sTBI and are helpful in determining the most impactful studies within this field. METHODS: We performed a generalized search using the database of Web of Science, organized the references by the number of citations, and reviewed full length-articles for the top-100 most-cited articles on sTBI. The articles were classified according to focus. RESULTS: The top-100 articles were cited on average 326.4 times per paper. The Journal of Neurosurgery published the greatest number of top-100 cited articles (9 of 100). Authors from the United States published the majority (67%) of the most-cited articles. The most popular categories were "reviews and guidelines" and "etiology and epidemiology." CONCLUSIONS: The present study provides a cross-sectional summary of the 100 most-cited articles on sTBI, highlighting areas of research needing further investigation and development.

The Sellar Tumor: Metastasis or Chordoma?

Chordomas are uncommon, locally invasive chordate tumors, which are mostly observed in the axial skeleton. Numerous papers have described similar patients around different anatomic locations; however, rare document previously reported that intracranial chordoma was associated with clear cell renal cell carcinoma (ccRCC). The authors report a 51-year-old male patient with a history of right radical nephrectomy for ccRCC presented to us with progressive blurred vision. Ophthalmic examination showed vision loss and visual field defects. Magnetic resonance imaging demonstrated pituitary tumor with hemorrhage, which was compressing the optic chiasm. He underwent a transnasal endoscope resection of the sellar mass. The immediate postoperative pathologic result was simply considered to be pituitary metastasis from ccRCC. After further immunohistochemical study, pathology diagnosis was made the necessary corrections to be the sellar chordoma. The authors summarize this exceptional patient and review the pertinent literature briefly.

HOXD-AS1/miR-130a sponge regulates glioma development by targeting E2F8.

Glioma development is an extremely complex process with changes occurring in numerous genes. HOXD antisense growth-associated long noncoding RNA (HOXD-AS1), an important long noncoding RNA (lncRNA), is known to regulate metastasis-related gene expression in bladder cancer, ovarian cancer and neuroblastoma. Here, we elucidated the function and possible molecular mechanisms of lncRNA HOXD-AS1 in human glioma cells. Our results proved that HOXD-AS1 expression was upregulated in glioma tissues and in glioma cell lines. HOXD-AS1 overexpression promoted cell migration and invasion in vitro, whereas knockdown of HOXD-AS1 expression repressed these cellular processes. Mechanistic studies further revealed that HOXD-AS1 could compete with the transcription factor E2F8 to bind with miR-130a, thus affecting E2F8 expression. Additionally, reciprocal repression was observed between HOXD-AS1 and miR-130a, and miR-130a mediated the tumor-suppressive effects of HOXD-AS1 knockdown. Taken together, these results provide a comprehensive analysis of the role of HOXD-AS1 in glioma cells and offer important clues to understand the key roles of competing endogenous RNA (ceRNA) mechanisms in human glioma.

Bibliometric Analysis of Journals in the Field of Endoscopic Endonasal Surgery for Pituitary Adenomas.

Endoscopic endonasal surgery for pituitary adenomas is being performed more frequently worldwide in the recent years. This first bibliometric analysis was conducted aiming to have a microscopic view of research activities about endoscopic endonasal surgery for pituitary adenomas. The original articles about endoscopic endonasal surgery for pituitary adenomas were extracted from the Web of Science (WoS) and analyzed concerning their distributions. We also explored the potential correlations between publications of different countries and their gross domestic product (GDP) via Pearson correlation test. The total number of original articles retrieved from WoS was 307 from 1997 to 2017. The number of original articles published in the last decade has increased by 530.95% compared with that published in the former decade. The United States has published 124 articles (40.391%), followed by Italy with 40 (13.029%) and Japan with 27 articles (8.795%). The journal that published the highest number of original articles was Journal of Neurosurgery with 31 (10.098%), followed by Neurosurgery (n = 23, 7.492%), World Neurosurgery (n = 23, 7.492%), and Neurosurgical Focus (n = 15, 4.886%). There was a strong correlation between publication numbers and GDP of different countries (r = 0.889, P < 0.001). There is a skyrocket trend of endoscopic endonasal surgery for pituitary adenomas during the last 2 decades, and countries with high GDP tend to make more contributions to this field.

Hedgehog/Gli1 signaling pathway regulates MGMT expression and chemoresistance to temozolomide in human glioblastoma.

BACKGROUND: Chemoresistance of glioblastoma (GBM) is a feature of this devastating disease. This study is to determine the relationship between Hedgehog (HH)/Gli1 signaling pathway and chemoresistance to temozolomide (TMZ) in human GBM. METHODS: We analyzed Gli1 nuclear staining and O6-methylguanine DNA methyltransferase (MGMT) expression in 48 cases of primary GBM tissues by immunohistochemistry. Quantitative PCR, western blot, methylation-specific PCR, cell proliferation and apoptosis assay were used to investigate changes of MGMT expression and chemosensitivity to TMZ after manipulating HH/Gli1 signaling activity in A172 and U251 GBM cell lines. Chromatin immunoprecipitation assay was utilized to identify potential Gli1 potential binding sites in MGMT gene promoter region. We established GBM xenografts using U251 cells to assess whether inhibiting HH/Gli1 signaling activity restored chemosensitivity to TMZ. RESULTS: O6-Methylguanine DNA methyltransferase-positive GBM tissues had a significantly higher rate of Gli1 nuclear staining than MGMT-negative ones (67.7% vs. 32.3%, p = 0.0159). Activation of HH/Gli1 signaling by pcDNA3.1-Gli1 cell transfection in A172 cells led to increased MGMT expression and enhanced resistance to TMZ treatment. Inhibition of the HH/Gli1 signaling by cyclopamine in U251 cells resulted in decreased MGMT expression and increased sensitivity to TMZ treatment. Both ways altered MGMT levels without changing the MGMT promoter methylation. The potential binding site of Gli1 in the MGMT gene promoter region was located at - 411 to - 403 bp upstream the transcriptional start site. The in vivo study revealed a synergistic effect on tumor growth inhibition with the combined administration of cyclopamine and TMZ. CONCLUSIONS: This study shows that HH/Gli1 signaling pathway regulates MGMT expression and chemoresistance to TMZ in human GBM independent from MGMT promoter methylation status, which offers a potential target to restore chemosensitivity to TMZ in a fraction of GBM with high MGMT expression.

MiR-148a increases glioma cell migration and invasion by downregulating GADD45A in human gliomas with IDH1 R132H mutations.

High-grade gliomas are severe tumors with poor prognosis. An R132H mutation in the isocitrate dehydrogenase (IDH1) gene prolongs the life of glioma patients. In this study, we investigated which genes are differentially regulated in IDH1 wild type (IDH1WT) or IDH1 R132H mutation (IDH1R132H) glioblastoma cells. Growth arrest and DNA-damage-inducible protein (GADD45A) was downregulated and microRNA 148a (miR-148a) was upregulated in in IDH1R132H human glioblastomas tissues. The relationship between GADD45A and miR-148a is unknown. In vitro experiments showed that GADD45A negatively regulates IDH1R132H glioma cell proliferation, migration, and invasion, and neurosphere formation in IDH1R132H glioblastoma stem cells (GSC). In addition, a human orthotopic xenograft mouse model showed that GADD45A reduced tumorigenesis in vivo. Our findings demonstrated that miR-148a promotes glioma cell invasion and tumorigenesis by downregulating GADD45A. Our findings provide novel insights into how GADD45A is downregulated by miR-148a in IDH1R132H glioma and may help to identify therapeutic targets for the effective treatment of high-grade glioma.

KLF4 Knockdown Attenuates TBI-Induced Neuronal Damage through p53 and JAK-STAT3 Signaling.

AIMS: Traumatic brain injury (TBI) is induced by complex primary and secondary mechanisms that give rise to cell death, inflammation, and neurological dysfunction. Understanding the mechanisms that drive neurological damage as well as those that promote repair can guide the development of therapeutic drugs for TBI. Kruppel-like factor 4 (KLF4) has been reported to negatively regulate axon regeneration of injured retinal ganglion cells (RGCs) through inhibition of JAK-STAT3 signaling. However, the role of KLF4 in TBI remains unreported. Reactive oxygen species (ROS)-induced neuronal death is a pathophysiological hallmark of TBI. METHODS: In this study, we used H2 O2 -treated RGCs in vitro and the optic nerve crush model in vivo to simulate neuronal damage in TBI. The function of KLF4 in RGC survival and axon regeneration in these models was investigated. In addition, the effects of KLF4 knockdown on neuronal damage after a brain impact that mimics moderate TBI were studied. RESULTS: The results show that H2 O2 induces p53-dependent apoptosis of RGCs in vitro through upregulation of KLF4. Additionally, KLF4 knockdown in vivo significantly enhances CNTF-induced axon regeneration of RGCs after optic nerve crush, and more importantly, prevents neuronal damage after a moderate brain impact in rats. Our Western blot analysis and immunoprecipitation assay results indicate that these effects of KLF4 knockdown are mediated by the p53 and JAK-STAT3 pathways. CONCLUSION: These findings provide evidence that KLF4 plays an important role in the pathophysiology of TBI. Blocking KLF4 may be a potential therapeutic strategy for the treatment of TBI, either alone or in combination with agents that target complementary mechanisms.

CACNA2D3 is downregulated in gliomas and functions as a tumor suppressor.

CACNA2D3, an auxiliary member of the alpha-2/delta subunit three family of the voltage-dependent calcium channel complex, plays a critical role in tumor suppression. However, its role in glioma carcinogenesis remains largely unknown. Here, we investigated the putative tumor suppressive role of CACNA2D3 in gliomas. Downregulation of CACNA2D3 was frequently detected in glioma tissues and cells compared with their non-tumorigenic counterparts, and correlated with poor survival. To investigate the underlying mechanism of CACNA2D3 in the development and progression of glioma, we performed CACNA2D3 ectopic expression in glioma cells (U87 and U251) and knockdown of CACNA2D3 in LN229 cells and conducted in vitro and in vivo functional assays. Our findings showed that increased intracellular calcium (Ca2+ ) mediated by overexpression of CACNA2D3 induced mitochondrial-mediated apoptosis, upregulation of NLK (through the Wnt/Ca2+ pathway) and inhibition of the epithelial-to-mesenchymal transition. Ectopic expression of CACNA2D3 inhibited cell proliferation, migration, invasion, and tumor growth in vitro and in vivo, whereas CACNA2D3 depletion inhibited cell viability and invasion. Furthermore, we confirmed that CACNA2D3 increased NLK expression in vitro by immunostaining and found that downregulation of CACNA2D3 in glioma cells and high-grade glioma tissue was accompanied by increased methylation. A reporter assay showed increased luciferase activity in NLK knockdown glioma cells and transcriptional activity of ß-cantenin/TCF was remarkably enhanced, which further confirmed that NLK antagonizes Wnt signaling-mediated anchorage-dependent and independent cell proliferation and invasion. This mechanism may contribute to a better understanding of glioma cancer pathogenesis and facilitate the development of new therapeutic strategies for the treatment of this disease. © 2016 Wiley Periodicals, Inc.

Traumatic brain injury: a review of characteristics, molecular basis and management.

Traumatic brain injury (TBI) is a critical cause of hospitalization, disability, and death worldwide. The global increase in the incidence of TBI poses a significant socioeconomic burden. Guidelines for the management of acute TBI mostly pertain to emergency treatment. Comprehensive gene expression analysis is currently available for several animal models of TBI, along with enhanced understanding of the molecular mechanisms activated during injury and subsequent recovery. The current review focuses on the characteristics, molecular basis and management of TBI.

R132H mutation in IDH1 gene reduces proliferation, cell survival and invasion of human glioma by downregulating Wnt/ß-catenin signaling.

Mutations in the isocitrate dehydrogenase 1 (IDH1) gene commonly occur in gliomas. Remarkably, the R132H mutation in IDH1 (IDH1-R132H) is associated with better prognosis and increased survival than patients lacking this mutation. The molecular mechanism underlying this phenomenon is largely unknown. In this study, we investigated potential cross-talk between IDH1-R132H and Wnt/ß-catenin signaling in regulating the cellular properties of human glioma. Although aberrant nuclear accumulation of ß-catenin is linked to the malignant progression of gliomas, its association with IDH1 remains unknown. We identified an inverse correlation between IDH1-R132H and the expression and activity of ß-catenin in human gliomas. In addition, overexpression of IDH1-R132H in glioblastoma cell lines U87 and U251 led to reduced cell proliferation, migration and invasion, accompanied by increased apoptosis. At the molecular level, we detected a significant reduction in the expression, nuclear accumulation and activity of ß-catenin following overexpression of IDH1-R132H. A microarray-based comparison of gene expression indicated that several mediators, effectors and targets of Wnt/ß-catenin signaling are downregulated, while negative regulators are upregulated in IDH1-R132H gliomas. Further, overexpression of ß-catenin in IDH1-R132H glioma cells restored the cellular phenotype induced by this mutation. Specifically, ß-catenin abrogated the decrease in proliferation, invasion and migration, and the increase in apoptosis, triggered by overexpression of IDH1-R132H. Finally, we demonstrate that xenografts of IDH1-R132H overexpressing U87 cells can significantly decrease the growth of tumors in vivo. Altogether, our results strongly suggest that the R132H mutation in IDH1 serves a tumor suppressor function in human glioma by negatively regulating Wnt/ß-catenin signaling.