Glutamine Metabolism Heterogeneity in Glioblastoma Unveils an Innovative Combination Therapy Strategy.

Treatment of glioblastoma multiforme (GBM) remains challenging. Unraveling the orchestration of glutamine metabolism may provide a novel viewpoint on GBM therapy. The study presented a full and comprehensive comprehending of the glutamine metabolism atlas and heterogeneity in GBM for facilitating the development of a more effective therapeutic choice. Transcriptome data from large GBM cohorts were integrated in this study. A glutamine metabolism-based classification was established through consensus clustering approach, and a classifier by LASSO analysis was defined for differentiating the classification. Prognosis, signaling pathway activity, tumor microenvironment, and responses to immune checkpoint blockade (ICB) and small molecular drugs were characterized in each cluster. A combinational therapy of glutaminase inhibitor CB839 with dihydroartemisinin (DHA) was proposed, and the influence on glutamine metabolism, apoptosis, reactive oxygen species (ROS), and migration was measured in U251 and U373 cells. We discovered that GBM presented heterogeneous glutamine metabolism-based clusters, with unique survival outcomes, activity of signaling pathways, tumor microenvironment, and responses to ICB and small molecular compounds. In addition, the classifier could accurately differentiate the two clusters. Strikingly, the combinational therapy of CB839 with DHA synergistically attenuated glutamine metabolism, triggered apoptosis and ROS accumulation, and impaired migrative capacity in GBM cells, demonstrating the excellent preclinical efficacy. Altogether, our findings unveil the glutamine metabolism heterogeneity in GBM and propose an innovative combination therapy of CB839 with DHA for this malignant disease.

Long non-coding RNA PSMA3-AS1 promotes glioma progression through modulating the miR-411-3p/HOXA10 pathway.

BACKGROUND: Glioma is a common type of brain tumor and is classified as low and high grades according to morphology and molecules. Growing evidence has proved that long non-coding RNAs (lncRNAs) play pivotal roles in numerous tumors or diseases including glioma. Proteasome 20S subunit alpha 3 antisense RNA 1 (PSMA3-AS1), as a member of lncRNAs, has been disclosed to play a tumor-promoting role in cancer progression. However, the role of PSMA3-AS1 in glioma remains unknown. Therefore, we concentrated on researching the regulatory mechanism of PSMA3-AS1 in glioma. METHODS: PSMA3-AS1 expression was detected using RT-qPCR. Functional assays were performed to measure the effects of PSMA3-AS1 on glioma progression. After that, ENCORI ( http://starbase.sysu.edu.cn/ ) database was used to predict potential genes that could bind to PSMA3-AS1, and miR-411-3p was chosen for further studies. The interaction among PSMA3-AS1, miR-411-3p and homeobox A10 (HOXA10) were confirmed through mechanism assays. RESULTS: PSMA3-AS1 was verified to be up-regulated in glioma cells and promote glioma progression. Furthermore, PSMA3-AS1 could act as a competitive endogenous RNA (ceRNA) for miR-411-3p to regulate HOXA10 and thus affecting glioma progression. CONCLUSION: PSMA3-AS1 stimulated glioma progression via the miR-411-3p/HOXA10 pathway, which might offer a novel insight for the therapy and treatment of glioma.

Upregulation of DEAD box helicase 5 and 17 are correlated with the progression and poor prognosis in gliomas.

Recent researches indicated Ddx5 and Ddx17 play crucial roles in tumorigenesis. However, the study of Ddx5 and Ddx17 in glioma remains a little. Our study investigated their expression in glioma and evaluated its association with clinical factors and prognostic significance. The expression of Ddx5 and Ddx17 were both upregulated in glioma tissues compared to normal brain tissues, and a significant positive correlation between Ddx5 and Ddx17 expression was identified by statistical analysis. Immunohistochemical staining verified the expression of Ddx5 and Ddx17 in peritumoral zone was lower than that in core zone but higher than normal brain tissues. Moreover, the increased expression of Ddx5 and Ddx17 was markedly correlated with WHO Grade and histological type, and high Ddx5 and Ddx17 were found to be significantly associated with the worse overall survival of glioma patients. In additional, higher expression of both Ddx5 and Ddx17 predicted shorter clinical survival time for high-grade glioma patients with radiotherapy or with chemotherapy. In conclusion, overexpressed Ddx5 and Ddx17 are involved in the clinical progression and poor prognosis of glioma patients, suggesting that their upregulation can be used as a reliable clinical predictor for tumor diagnosis and to predict survival in patients with glioma.

Hes1 Knockdown Exacerbates Ischemic Stroke Following tMCAO by Increasing ER Stress-Dependent Apoptosis via the PERK/eIF2α/ATF4/CHOP Signaling Pathway.

Apoptosis induced by endoplasmic reticulum (ER) stress plays a crucial role in mediating brain damage after ischemic stroke. Recently, Hes1 (hairy and enhancer of split 1) has been implicated in the regulation of ER stress, but whether it plays a functional role after ischemic stroke and the underlying mechanism remain unclear. In this study, using a mouse model of ischemic stroke via transient middle cerebral artery occlusion (tMCAO), we found that Hes1 was induced following brain injury, and that siRNA-mediated knockdown of Hes1 increased the cerebral infarction and worsened the neurological outcome, suggesting that Hes1 knockdown exacerbates ischemic stroke. In addition, mechanistically, Hes1 knockdown promoted apoptosis and activated the PERK/eIF2α/ATF4/CHOP signaling pathway after tMCAO. These results suggest that Hes1 knockdown promotes ER stress-induced apoptosis. Furthermore, inhibition of PERK with the specific inhibitor GSK2606414 markedly attenuated the Hes1 knockdown-induced apoptosis and the increased cerebral infarction as well as the worsened neurological outcome following tMCAO, implying that the protection of Hes1 against ischemic stroke is associated with the amelioration of ER stress via modulating the PERK/eIF2α/ATF4/CHOP signaling pathway. Taken together, these results unveil the detrimental role of Hes1 knockdown after ischemic stroke and further relate it to the regulation of ER stress-induced apoptosis, thus highlighting the importance of targeting ER stress in the treatment of ischemic stroke.

[Curcumin suppresses invasiveness and migration of human glioma cells in vitro by inhibiting HDGF/ß-catenin complex].

OBJECTIVE: To investigate the effect of curcumin on the invasion and migration of human glioma cells in vitro and explore the molecular mechanisms. METHODS: MTT assay was used for screening the optimal curcumin concentrations. The effects of curcumin on the invasion and metastasis of human glioma cell lines U251 and LN229 were tested using Transwell assay, Boyden assay and wound-healing assays. The expression of the related proteins and their interactions were determined using Western blotting and coimmunoprecipitation assay. RESULTS: Curcumin at the concentration of 20 µmol/L for 48 h was used as the optimal condition for subsequent cell treatment. In the two glioma cell lines, curcumin significantly suppressed the invasion and migration of the cells (P < 0.05) and lowered the expressions of hepatoma-derived growth factor (HDGF), Ncadherin, vimentin, Snail and Slug, but increased the expression of E-cadherin. Interference of HDGF in curcumin-treated glioma cells synergistically inhibited the epithelial-mesenchymal transition (EMT) signals, while overexpression of HDGF significantly reversed the inhibitory effect of curcumin on EMT; curcumin treatment could significantly reduce the binding of HDGF to ß-catenin. CONCLUSIONS: Curcumin suppresses EMT signal by reducing HDGF/ß-catenin complex and thereby lowers the migration and invasion abilities of human glioma cells in vitro.

Phytanoyl-CoA 2-Hydroxylase-Interacting Protein-Like Gene Is a Therapeutic Target Gene for Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most common primary CNS cancer and has a poor prognosis. This study searched for significant genes and the mechanisms involved in GBM. We used the Gene Expression Omnibus (GEO) to test the WHO normal and IV glioma database, used R tool to identify the significant gene, and finally, combined these with The Cancer Genome Atlas (TCGA) to verify the significant genes. Subsequently, we explored the biological mechanisms involved. Phytanoyl-CoA 2-hydroxylase-interacting protein-like gene (PHYHIPL) is downregulated in grade IV glioma (GBM). The downregulation of PHYHIPL in GBM is accompanied by poor overall survival in the TCGA database, which indicates that PHYHIPL is a protection gene in GBM development. Bioinformatics analysis shows that the poor prognosis with downregulated PHYHIPL may be the result of the TNF signaling pathway and the IL-17 signaling pathway, but good prognosis accompanied by upregulated PHYHIPL may be the result of retrograde endocannabinoid signaling and the cAMP signaling pathway. Protein-protein interactions (PPI) net indicated that PHYHIPL may play a vital role in cell metabolism, and we hypothesize that the downregulation mechanism may be the result of mutations of the ß-catenin gene and the endogenous siRNA, as shown in previous studies. PHYHIPL may be a target gene for the treatment and prognosis of GBM.

Omega-3 polyunsaturated fatty acid attenuates traumatic brain injury-induced neuronal apoptosis by inducing autophagy through the upregulation of SIRT1-mediated deacetylation of Beclin-1.

BACKGROUND: Enhancing autophagy after traumatic brain injury (TBI) may decrease the expression of neuronal apoptosis-related molecules. Autophagy-mediated neuronal survival is regulated by the sirtuin family of proteins (SIRT). Omega-3 polyunsaturated fatty acids (ω-3 PUFA) are known to have antioxidative and anti-inflammatory effects. We previously demonstrated that ω-3 PUFA supplementation attenuated neuronal apoptosis by modulating the neuroinflammatory response through SIRT1-mediated deacetylation of the HMGB1/NF-κB pathway, leading to neuroprotective effects following experimental traumatic brain injury (TBI). However, no studies have elucidated if the neuroprotective effects of ω-3 PUFAs against TBI-induced neuronal apoptosis are modulated by SIRT1-mediated deacetylation of the autophagy pathway. METHODS: The Feeney DM TBI model was adopted to induce TBI rats. Modified neurological severity scores, the rotarod test, brain water content, and Nissl staining were employed to determine the neuroprotective effects of ω-3 PUFA supplementation. Immunofluorescent staining and western blot analysis were used to detect Beclin-1 nuclear translocation and autophagy pathway activation. The impact of SIRT1 deacetylase activity on Beclin-1 acetylation and the interaction between cytoplasmic Beclin-1 and Bcl-2 were assessed to evaluate the neuroprotective effects of ω-3 PUFAs and to determine if these effects were dependent on SIRT1-mediated deacetylation of the autophagy pathway in order to gain further insight into the mechanisms underlying the development of neuroprotection after TBI. RESULTS: ω-3 PUFA supplementation protected neurons against TBI-induced neuronal apoptosis via enhancement of the autophagy pathway. We also found that treatment with ω-3 PUFA significantly increased the NAD+/NADH ratio and SIRT1 activity following TBI. In addition, ω-3 PUFA supplementation increased Beclin-1 deacetylation and its nuclear export and induced direct interactions between cytoplasmic Beclin-1 and Bcl-2 by increasing SIRT1 activity following TBI. These events led to the inhibition of neuronal apoptosis and to neuroprotective effects through enhancing autophagy after TBI, possibly due to elevated SIRT1. CONCLUSIONS: ω-3 PUFA supplementation attenuated TBI-induced neuronal apoptosis by inducing the autophagy pathway through the upregulation of SIRT1-mediated deacetylation of Beclin-1.

Nerve growth factor and substance P may be involved in moist exposed burn ointment-mediated chronic refractory wound healing.

Moist exposed burn ointment (MEBO) is becoming increasingly popular in China as it shortens wound-healing time and reduces scar formation. However, its exact mechanism in mediating the wound-healing process is not yet clear. In the present study a total of 90 healthy adult male Wistar rats of specific-pathogen-free grade were divided equally into a control group, wound group, MEBO group, recombinant bovine basic fibroblast growth factor (rb-bFGF) group and sham operation group. Wound healing was observed from the extracted granulation tissues and recorded at three time points on 3, 7 and 14 days. Different levels of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in tissue homogenate were detected using ELISA. Western blot analysis and quantitative PCR were used to detect the expression of nerve growth factor (NGF), substance P (SP) as well as tyrosine kinase A (TrkA) receptor protein and the corresponding mRNA levels in granulation tissue. It was observed that the wound healing progressed faster in the MEBO and rb-bFGF groups compared with the wound group (P<0.01). TNF-α and IL-6 had an upward-downward trend at three time points, with the wound group demonstrating the most obvious increase (P<0.01). NGF and SP mRNA and protein levels in granulation tissue in MEBO, rb-bFGF and sham operation groups reached their highest levels on day 7 and then decreased on day 14. The expression level of TrkA was also measured simultaneously and its expression pattern was similar to that of NGF and SP. These results suggested that MEBO may promote nerve repair and accelerate wound healing through mediating the expression levels of NGF and SP, as well as TrkA.

Valproic acid attenuates traumatic spinal cord injury-induced inflammation via STAT1 and NF-κB pathway dependent of HDAC3.

BACKGROUND: Microglial polarization with M1/M2 phenotype shifts and the subsequent neuroinflammatory responses are vital contributing factors for spinal cord injury (SCI)-induced secondary injury. Nuclear factor-κB (NF-κB) is considered the central transcription factor of inflammatory mediators, which plays a crucial role in microglial activation. Lysine acetylation of STAT1 seems necessary for NF-kB pathway activity, as it is regulated by histone deacetylases (HDACs). There have been no studies that have explained if HDAC inhibition by valproic acid (VPA) affects the NF-κB pathway via acetylation of STAT1 dependent of HDAC activity in the microglia-mediated central inflammation following SCI. We investigated the potential molecular mechanisms that focus on the phenotypic transition of microglia and the STAT1-mediated NF-κB acetylation after a VPA treatment. METHODS: The Basso-Beattie-Bresnahan locomotion scale, the inclined plane test, the blood-spinal cord barrier, and Nissl staining were employed to determine the neuroprotective effects of VPA treatment after SCI. Assessment of microglia polarization and pro-inflammatory markers, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and interferon (INF)-γ was used to evaluate the neuroinflammatory responses and the anti-inflammatory effects of VPA treatment. Immunofluorescent staining and Western blot analysis were used to detect HDAC3 nuclear translocation, activity, and NF-κB signaling pathway activation to evaluate the effects of VPA treatment. The impact of STAT1 acetylation on NF-kB pathway and the interaction between STAT1 and NF-kB were assessed to evaluate anti-inflammation effects of VPA treatment and also whether these effects were dependent on a STAT1/NF-κB pathway to gain further insight into the mechanisms underlying the development of the neuroinflammatory response after SCI. RESULTS: The results showed that the VPA treatment promoted the phenotypic shift of microglia from M1 to M2 phenotype and inhibited microglial activation, thus reducing the SCI-induced inflammatory factors. The VPA treatment upregulation of the acetylation of STAT1/NF-κB pathway was likely caused by the HDAC3 translocation to the nucleus and activity. These results indicated that the treatment with the VPA suppressed the expression and the activity of HDAC3 and enhanced STAT1, as well as NF-κB p65 acetylation following a SCI. The acetylation status of NF-kB p65 and the complex with NF-κB p65 and STAT1 inhibited the NF-kB p65 transcriptional activity and attenuated the microglia-mediated central inflammatory response following SCI. CONCLUSIONS: These results suggested that the VPA treatment attenuated the inflammatory response by modulating microglia polarization through STAT1-mediated acetylation of the NF-κB pathway, dependent of HDAC3 activity. These effects led to neuroprotective effects following SCI.

Omega-3 polyunsaturated fatty acid attenuates the inflammatory response by modulating microglia polarization through SIRT1-mediated deacetylation of the HMGB1/NF-κB pathway following experimental traumatic brain injury.

BACKGROUND: Microglial polarization and the subsequent neuroinflammatory response are contributing factors for traumatic brain injury (TBI)-induced secondary injury. High mobile group box 1 (HMGB1) mediates the activation of the NF-κB pathway, and it is considered to be pivotal in the late neuroinflammatory response. Activation of the HMGB1/NF-κB pathway is closely related to HMGB1 acetylation, which is regulated by the sirtuin (SIRT) family of proteins. Omega-3 polyunsaturated fatty acids (ω-3 PUFA) are known to have antioxidative and anti-inflammatory effects. We previously demonstrated that ω-3 PUFA inhibited TBI-induced microglial activation and the subsequent neuroinflammatory response by regulating the HMGB1/NF-κB signaling pathway. However, no studies have elucidated if ω-3 PUFA affects the HMGB1/NF-κB pathway in a HMGB1 deacetylation of dependent SIRT1 manner, thus regulating microglial polarization and the subsequent neuroinflammatory response. METHODS: The Feeney DM TBI model was adopted to induce brain injury in rats. Modified neurological severity scores, rotarod test, brain water content, and Nissl staining were employed to determine the neuroprotective effects of ω-3 PUFA supplementation. Assessment of microglia polarization and pro-inflammatory markers, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and HMGB1, were used to evaluate the neuroinflammatory responses and the anti-inflammatory effects of ω-3 PUFA supplementation. Immunofluorescent staining and western blot analysis were used to detect HMGB1 nuclear translocation, secretion, and HMGB1/NF-κB signaling pathway activation to evaluate the effects of ω-3 PUFA supplementation. The impact of SIRT1 deacetylase activity on HMGB1 acetylation and the interaction between HMGB1 and SIRT1 were assessed to evaluate anti-inflammation effects of ω-3 PUFAs, and also, whether these effects were dependent on a SIRT1-HMGB1/NF-κB axis to gain further insight into the mechanisms underlying the development of the neuroinflammatory response after TBI. RESULTS: The results of our study showed that ω-3 PUFA supplementation promoted a shift from the M1 microglial phenotype to the M2 microglial phenotype and inhibited microglial activation, thus reducing TBI-induced inflammatory factors. In addition, ω-3 PUFA-mediated downregulation of HMGB1 acetylation and its extracellular secretion was found to be likely due to increased SIRT1 activity. We also found that treatment with ω-3 PUFA inhibited HMGB1 acetylation and induced direct interactions between SIRT1 and HMGB1 by elevating SIRT1 activity following TBI. These events lead to inhibition of HMGB1 nucleocytoplasmic translocation/extracellular secretion and alleviated HMGB1-mediated activation of the NF-κB pathway following TBI-induced microglial activation, thus inhibiting the subsequent inflammatory response. CONCLUSIONS: The results of this study suggest that ω-3 PUFA supplementation attenuates the inflammatory response by modulating microglial polarization through SIRT1-mediated deacetylation of the HMGB1/NF-κB pathway, leading to neuroprotective effects following experimental traumatic brain injury.

Sevoflurane post-conditioning attenuates traumatic brain injury-induced neuronal apoptosis by promoting autophagy via the PI3K/AKT signaling pathway.

BACKGROUND: Sevoflurane post-conditioning exerts nerve-protective effects through inhibiting caspase-dependent neuronal apoptosis after a traumatic brain injury (TBI). Autophagy that is induced by the endoplasmic reticulum stress plays an important role in the secondary neurological dysfunction after a TBI. However, the relationship between autophagy and caspase-dependent apoptosis as well as the underlying nerve protection mechanism that occurs with sevoflurane post-conditioning following a TBI remains unclear. METHODS: The Feeney TBI model was used to induce brain injury in rats. Evaluation of the modified neurological severity scores, measurement of brain water content, Nissl staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay were used to determine the neuroprotective effects of the sevoflurane post-conditioning. Both immunofluorescence and Western blot analyses were used to detect the expression of autophagy-related proteins microtubule-associated protein 1 light chain 3-II and Beclin-1, pro-apoptotic factors, as well as the activation of the phosphatidylinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway within the lesioned cortex. RESULTS: Autophagy and neuronal apoptosis were activated in the lesioned cortex following the TBI. Sevoflurane post-conditioning enhanced early autophagy, suppressed neuronal apoptosis, and alleviated brain edema, which improved nerve function after a TBI (all P < 0.05). Sevoflurane post-conditioning induced the activation of PI3K/AKT signaling after the TBI (P < 0.05). The neuroprotective effects of sevoflurane post-conditioning were reversed through the autophagy inhibitor 3-methyladenine treatment. CONCLUSION: Neuronal apoptosis and the activation of autophagy were involved in the secondary neurological injury following a TBI. Sevoflurane post-conditioning weakened the TBI-induced neuronal apoptosis by regulating autophagy via PI3K/AKT signaling.

KLF16 suppresses human glioma cell proliferation and tumourigenicity by targeting TFAM.

BACKGROUND: This study aims to via unveiling the novel mechanisms of KLF16 in regulating expression of genes involved in glioma. METHODS: KLF16 or KLF16-siRNA was transfected to U87MG cells by lentivirus. Colony formation assay was applied for detecting cell proliferation. MTT assay was adopted to assess cell viability. TUNEL assay was selected to evaluate cell apoptosis. Flow cytometry was used to determine cell cycle. Real-time PCR was performed to test mRNA expression. Western blot was used to detect protein level. Luciferase assay was applied to confirm the regulatory relationship between KLF16 and Mitochondrial transcription factor A (TFAM). Chromatin immunoprecipitation was adopted to test the protein binding site. The nude mouse transplantation tumour experiment was selected to test cancer cell proliferation in vivo. RESULTS: KLF16 was decreased in glioma cells and tissues. KLF16 obviously restrained U87MG cell proliferation both in vivo and in vitro. KLF16 transfection reduced mRNA and protein levels related to cell proliferation. KLF16 targeted a putative binding site near the transcription start sites (TSSs) of TFAM gene, thus suppressing glioma cell proliferation. KLF16-siRNA exhibited the opposite impact. KLF16 presented significant negative correlation with TFAM level in glioma patients. CONCLUSIONS: KLF16 is a key regulator of glioma cell proliferation by directly targeting TFAM.

The expression of MMP19 and its clinical significance in glioma.

AIMS: The expression of phosphoglycerate kinase 1 (MMP19) is elevated in some cancers. However, the clinical features and prognostic value of glioma patients with MMP19 expression are unclear. In this study, the expression level of MMP19 and the correlation between the level of MMP19 expression and the clinicopathologic data in glioma patients including survival were examined. METHODS AND RESULTS: Using real-time PCR, the mRNA expression of MMP19 was examined in 61 fresh glioma tissues and 32 brain samples. The result indicated that MMP19 mRNA was obviously elevated in glioma tissues compared to brain tissues. Further, we observed that MMP19 mRNA was much higher in stage III patients than it was in stage I-II patients. The expression of the MMP19 protein was determined by immunohistochemical analysis in 156 paraffin-embedded glioma samples and 35 normal paraffin-embedded brain samples. The MMP19 protein level was significantly increased in glioma tissues compared to brain tissues (P = 0.008). Furthermore, we observed that a high expression of MMP19 protein was positively associated with clinical stage (P = 0.008) but did not correlate with age, gender, or histological type. An increased MMP19 protein expression was associated with poor overall survival rates (P = 0.001). A stratified analysis showed that patients with high MMP19 protein expression indicated a worse prognosis occurring in WHO III-IV stages (P = 0.001). A Multivariate analysis indicated that a high expression of the MMP19 protein was an independent prognostic indicator of patient survival (P = 0.009). CONCLUSIONS: MMP19 is overexpressed and plays a significant role in disease progression and poor outcome in glioma patients.

[Small interfering RNA-mediated α-enolase knockdown suppresses glycolysis and proliferation of human glioma U251 cells in vitro].

OBJECTIVE: To investigate the role of α-enolase (ENO1) in regulating glucose metabolism and cell growth in human glioma cells. METHODS: Glucose uptake and lactate generation were assessed to evaluate the changes in glucose metabolism in human glioma U251 cells with small interfering RNA (siRNA)-mediated ENO1 knockdown. MTT assay and 5-ethynyl-2'-deoxyuridine (EdU) staining were used to examine the cell growth and cell cycle changes following siRNA transfection of the cells. RESULTS: Transfection of U251 cells with siRNA-ENO1 markedly reduced glucose uptake (P=0.023) and lactate generation (P=0.007) in the cells and resulted in significant suppression of cell proliferation (*P<0.05) since the second day following the transfection. Transfection with siRNA-ENO1 also obviously suppressed cell cycle G1/S transition in the cells (P=0.0425). The expressions of HK2 and LDHA, the marker genes for glucose metabolism, were significantly down-regulated in the cells with siRNA-mediated ENO1 knockdown. CONCLUSION: ENO1 as a potential oncogene promotes glioma cell growth by positively modulating glucose metabolism.

Omega-3 polyunsaturated fatty acid supplementation attenuates microglial-induced inflammation by inhibiting the HMGB1/TLR4/NF-κB pathway following experimental traumatic brain injury.

BACKGROUND: Microglial activation and the subsequent inflammatory response in the central nervous system play important roles in secondary damage after traumatic brain injury (TBI). High-mobility group box 1 (HMGB1) protein, an important mediator in late inflammatory responses, interacts with transmembrane receptor for advanced glycation end products (RAGE) and toll-like receptors (TLRs) to activate downstream signaling pathways, such as the nuclear factor (NF)-κB signaling pathway, leading to a cascade amplification of inflammatory responses, which are related to neuronal damage after TBI. Omega-3 polyunsaturated fatty acid (ω-3 PUFA) is a commonly used clinical immunonutrient, which has antioxidative and anti-inflammatory effects. However, the effects of ω-3 PUFA on HMGB1 expression and HMGB1-mediated activation of the TLR4/NF-κB signaling pathway are not clear. METHODS: The Feeney DM TBI model was adopted to induce brain injury in rats. Modified neurological severity scores, brain water content, and Nissl staining were employed to determine the neuroprotective effects of ω-3 PUFA supplementation. Assessment of microglial activation in lesioned sites and protein markers for proinflammatory, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, interferon (IFN)-γ, and HMGB1 were used to evaluate neuroinflammatory responses and anti-inflammation effects of ω-3 PUFA supplementation. Immunofluorescent staining and western blot analysis were used to detect HMGB1 nuclear translocation, secretion, and HMGB1-mediated activation of the TLR4/NF-κB signaling pathway to evaluate the effects of ω-3 PUFA supplementation and gain further insight into the mechanisms underlying the development of the neuroinflammatory response after TBI. RESULTS: It was found that ω-3 PUFA supplementation inhibited TBI-induced microglial activation and expression of inflammatory factors (TNF-α, IL-1ß, IL-6, and IFN-γ), reduced brain edema, decreased neuronal apoptosis, and improved neurological functions after TBI. We further demonstrated that ω-3 PUFA supplementation inhibited HMGB1 nuclear translocation and secretion and decreased expression of HMGB1 in neurons and microglia in the lesioned areas. Moreover, ω-3 PUFA supplementation inhibited microglial activation and the subsequent inflammatory response by regulating HMGB1 and the TLR4/NF-κB signaling pathway. CONCLUSIONS: The results of this study suggest that microglial activation and the subsequent neuroinflammatory response as well as the related HMGB1/TLR4/NF-κB signaling pathway play essential roles in secondary injury after TBI. Furthermore, ω-3 PUFA supplementation inhibited TBI-induced microglial activation and the subsequent inflammatory response by regulating HMGB1 nuclear translocation and secretion and also HMGB1-mediated activation of the TLR4/NF-κB signaling pathway, leading to neuroprotective effects.

Tetrahydrocurcumin Provides Neuroprotection in Experimental Traumatic Brain Injury and the Nrf2 Signaling Pathway as a Potential Mechanism.

The protective effect of tetrahydrocurcumin (THC) after experimental traumatic brain injury (TBI) has been demonstrated, as demonstrated by the inhibition of oxidative stress, mitochondrial dysfunction, and apoptosis. However, the mechanisms underlying this effect are still not well understood. This study was to investigate the neuroprotective effects of THC, and its potential mechanisms, in a rat model of TBI. To this end, rats were divided into 4 groups: the sham group, the TBI group, the TBI + vehicle (V) group, and the TBI + THC group. THC or V was administered via intraperitoneal injection to rats in the TBI + V and TBI + THC groups 30 min after TBI. After euthanasia (24 h after TBI), neurological scores, brain water content, and neuronal cell death in the cerebral cortex were recorded. Brain samples were collected after neurological scoring for further analysis. THC treatment alleviated brain edema, attenuated TBI-induced neuronal cell apoptosis, and improved neurobehavioral function. In addition, NFE2-related factor 2 (Nrf2) expression was upregulated following TBI. These results suggest that THC improves neurological outcome after TBI, possibly by activating the Nrf2 signaling pathway.

[Lentivirus-mediated shRNA targeting ZNF217 suppresses cell growth, migration, and invasion of glioma cells in vitro].

OBJECTIVE: To explore the role of ZNF217 in regulating cell proliferation, migration and invasion in glioma cells. METHDOS: A lentivirus-mediated shRNA-ZNF217 vector was infected into glioma U251 cells, and the interference efficiency was examined by Western blotting. MTT assay, flow cytometry, Transwell assay, and Boyden chamber assay were used to analyze the changes in cell proliferation, migration and invasion. Western blotting was used to detect the changes in ZNF217-related genes in the cells. RESULTS: shRNA-ZNF217 transfection significantly inhibited the expression of ZNF217 in U251 cells and suppressed the cell migration, invasion, growth, and cell cycle transition. ZNF217 knockdown downregulated the expression of pPI3, pAKT, C-Myc, and the mesenchyme biomarker N-cadherin, and stimulated the expression of the epithelium biomarker E-cadherin. CONCLUSION: ZNF217 promotes cell migration, invasion, and growth by activating PI3K/AKT signal to upregulate C-Myc and by modulating the genes associated with epithelial-mesenchymal transition in glioma cells.

Interleukin-16 polymorphism is associated with an increased risk of glioma.

OBJECTIVE: Previous studies have shown that interleukin (IL)-16 is overexpressed in human and rat gliomas. Potential links between IL-16 polymorphisms and glioma risk are currently unclear. The aim of this study was to investigate the association between IL-16 polymorphisms and glioma risk. METHODS: We examined IL-16 gene polymorphisms (i.e., rs 4778889, rs 11556218, and rs 4072111) in 216 patients with glioma and 275 controls in a Chinese population. Genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were used to evaluate the effect of the IL-16 polymorphisms on glioma risk. RESULTS: The rs 11556218TG genotype is associated with an increased risk of glioma compared with the TT genotype (OR=1.76; 95% CI, 1.22-2.54; p=0.002). Similarly, the rs 11556218G allele is associated with an increased risk of glioma compared with the T allele (OR=1.41; 95% CI, 1.06-1.87; p=0.017). However, no significant association was observed between the IL-16 rs 4778889 and rs 4072111 polymorphisms and the risk of glioma. CONCLUSION: These findings suggest that the IL-16 rs 11556218 polymorphism may be used as a susceptibility marker for glioma.