Distinct clinical outcome of microcystic meningioma as a WHO grade 1 meningioma subtype.

OBJECTIVE: To evaluate the clinicopathological characteristics, radiology, and long-term outcomes of microcystic meningiomas (MM) and compare it with other subtypes of meningiomas managed at a single neurosurgical center. METHODS: A total of 87 consecutive patients who underwent surgical resection and were diagnosed as MM between 2005 and 2016 were enrolled for analysis. Clinicopathological, radiology, and prognostic information was collected and analyzed. Progression free survival (PFS) was compared with 659 patients with other subtypes of WHO grade 1 meningiomas and 167 patients with atypical meningiomas treated during the same period. RESULTS: Fifty six females and 31 males with MM were analyzed. Peri-tumor brain edema was frequent on T2 WI (85%).12 patients (13.8%) experienced tumor progression during the mean follow-up of 101.66 ± 40.92 months. The median PFS was unavailable, and the 5, 10, and 15 year progression-free rates were 96.9%, 84.0%, and 73.9%, respectively. Univariate COX analysis demonstrated skull base location and higher Ki-67 index as significant negative prognostic factors for PFS (P < 0.05); multivariate analysis identified tumor location and Ki-67 index as independent factors (P < 0.01), as well. Of note, the PFS of MM was worse than other WHO grade 1 subtypes (P < 0.001), but better than atypical meningiomas (P < 0.001), and the PFS differences were retained even when the analysis was limited to the patients receiving GTR (P < 0.05). CONCLUSION: The PFS of MM was worse than other WHO grade 1 subtypes and better than atypical meningiomas. Skull base location and higher Ki-67 index were independent negative prognostic factors in MM.

MMP-9 Inhibitor GM6001 Prevents the Development of ssTBI-Induced Parkinson's Disease via the Autophagy Pathway.

Concussion is a widely recognized environmental risk factor for neurodegenerative diseases, including Parkinson's disease (PD). Small-vessel disease of the brain has been reported to contribute to neurodegenerative diseases. In this study, we observed BBB disruption in wild-type (WT) mice, but not in matrix metalloproteinase 9 (MMP-9) knockout mice, subjected to single severe traumatic brain injury (ssTBI). Furthermore, treating ssTBI mice with the MMP-9 inhibitor GM6001 effectively maintained BBB integrity, promoted the elimination of damaged mitochondria via mitophagy, and then prevented neuronal death and progressive neurodegeneration. However, we did not observe this neuroprotective effect of MMP-9 inhibition in beclin-1-/+ mice. Collectively, these findings revealed that concussion led to BBB disruption via MMP-9, and that GM6001 prevented the development of PD via the autophagy pathway.

Nuclear receptor coactivator 4-mediated ferritinophagy contributes to cerebral ischemia-induced ferroptosis in ischemic stroke.

Ischemic stroke poses a significant health risk due to its high rate of disability and mortality. To address this problem, several therapeutic approaches have been proposed, including interruption targeting programmed cell death (PCD). Ferroptosis is a newly defined PCD characterized by iron-dependent accumulation of lipid peroxidation, and is becoming a promising target for treating numerous diseases. To explore the underlying mechanisms of the initiation and execution of ferroptosis in ischemic stroke, we established stroke models in vivo and in vitro simulating ischemia/reperfusion (I/R) neuronal injury. Different from previous reports on stroke, we tested ferroptosis by measuring the levels of core proteins, such as ACSL4, 15-LOX2, Ferritin and GPX4. In addition, I/R injury induces excessive degradation of ferritin via the autophagy pathway and subsequent increase of free iron in neurons. This phenomenon has recently been termed ferritinophagy and reported to be regulated by nuclear receptor coactivator 4 (NCOA4) in some cell lines. Increased NCOA4 in cytoplasm was detected in our study and then silenced by shRNA to investigate its function. Both in vivo and in vitro, NCOA4 deletion notably abrogated ferritinophagy caused by I/R injury and thus inhibited ferroptosis. Furthermore, we found that NCOA4 was upregulated by ubiquitin specific peptidase 14 (USP14) via a deubiquitination process in damaged neurons, and we found evidence of pharmacological inhibition of USP14 effectively reducing NCOA4 levels to protect neurons from ferritinophagy-mediated ferroptosis. These findings suggest a novel and effective target for treating ischemic stroke.

Cardiolipin-Dependent Mitophagy Guides Outcome after Traumatic Brain Injury.

Mitochondrial energy production is essential for normal brain function. Traumatic brain injury (TBI) increases brain energy demands, results in the activation of mitochondrial respiration, associated with enhanced generation of reactive oxygen species. This chain of events triggers neuronal apoptosis via oxidation of a mitochondria-specific phospholipid, cardiolipin (CL). One pathway through which cells can avoid apoptosis is via elimination of damaged mitochondria by mitophagy. Previously, we showed that externalization of CL to the mitochondrial surface acts as an elimination signal in cells. Whether CL-mediated mitophagy occurs in vivo or its significance in the disease processes are not known. In this study, we showed that TBI leads to increased mitophagy in the human brain, which was also detected using TBI models in male rats. Knockdown of CL synthase, responsible for de novo synthesis of CL, or phospholipid scramblase-3, responsible for CL translocation to the outer mitochondrial membrane, significantly decreased TBI-induced mitophagy. Inhibition of mitochondrial clearance by 3-methyladenine, mdivi-1, or phospholipid scramblase-3 knockdown after TBI led to a worse outcome, suggesting that mitophagy is beneficial. Together, our findings indicate that TBI-induced mitophagy is an endogenous neuroprotective process that is directed by CL, which marks damaged mitochondria for elimination, thereby limiting neuronal death and behavioral deficits.SIGNIFICANCE STATEMENT Traumatic brain injury (TBI) increases energy demands leading to activation of mitochondrial respiration associated with enhanced generation of reactive oxygen species and resultant damage to mitochondria. We demonstrate that the complete elimination of irreparably damaged organelles via mitophagy is activated as an early response to TBI. This response includes translocation of mitochondria phospholipid cardiolipin from the inner membrane to the outer membrane where externalized cardiolipin mediates targeted protein light chain 3-mediated autophagy of damaged mitochondria. Our data on targeting phospholipid scramblase and cardiolipin synthase in genetically manipulated cells and animals strongly support the essential role of cardiolipin externalization mechanisms in the endogenous reparative plasticity of injured brain cells. Furthermore, successful execution and completion of mitophagy is beneficial in the context of preservation of cognitive functions after TBI.

Up-regulation of CHMP4B alleviates microglial necroptosis induced by traumatic brain injury.

Microglial cells are key component of central nervous system (CNS) and mediate the immune response of the brain under physiological or pathological conditions. It tends to activate into a pro-inflammatory M1 phenotype after traumatic brain injury (TBI) and promote secondary brain damage. Recently, necroptosis was found to promote microglial activation and neuroinflammation after TBI. However, the mechanism and specific interventions of microglial necroptosis after TBI remain poorly investigated. Here, we reported that overexpress the charged multivesicular body protein 4b (CHMP4B) which is a core member of the endosomal sorting required for transport complex III (ESCRT-III) significantly decreased the level of necroptosis in microglia, improved neurological function recovery and protected against cell death after TBI. Further investigation showed that forkhead transcription factor O1 (FOXO1) was a crucial transcription factor that increased CHMP4B transcription by binding to the promoter region, thereby inhibiting necroptosis in microglia. Collectively, our findings demonstrated that CHMP4B relieved microglial necroptosis and neuroinflammation after TBI, and promote the recovery of nerve function. FOXO1 is an important factor in promoting CHMP4B expression. This study provides the novel viewpoint for TBI prevention and treatment.

LINC00511 contributes to glioblastoma tumorigenesis and epithelial-mesenchymal transition via LINC00511/miR-524-5p/YB1/ZEB1 positive feedback loop.

Tumour invasion is closely related to the prognosis and recurrence of glioblastoma multiforme and partially attributes to epithelial-mesenchymal transition. Long intergenic non-coding RNA 00511 (LINC00511) plays a pivotal role in tumour; however, the role of LINC00511 in GBM, especially in the epigenetic molecular regulation mechanism of EMT, is still unclear. Here, we found that LINC00511 was up-regulated in GBM tissues and relatively high LINC00511 expression predicted poorer prognosis. Moreover, ectopic LINC00511 enhanced GBM cells proliferation, EMT, migration and invasion, whereas LINC00511 knockdown had the opposite effects. Mechanistically, we confirmed that ZEB1 acted as a transcription factor for LINC00511 in GBM cells. Subsequently, we found that LINC00511 served as a competing endogenous RNA that sponged miR-524-5p to indirectly regulate YB1, whereas, up-regulated YB1 promoted ZEB1 expression, which inversely facilitated LINC00511 expression. Finally, orthotopic xenograft models were performed to further demonstrate the LINC00511 on GBM tumorigenesis. This study demonstrates that a LINC00511/miR-524-5p/YB1/ZEB1 positive feedback loop provides potential therapeutic targets for GBM progression.

S100A11 functions as novel oncogene in glioblastoma via S100A11/ANXA2/NF-κB positive feedback loop.

Glioblastoma (GBM) is the most universal type of primary brain malignant tumour, and the prognosis of patients with GBM is poor. S100A11 plays an essential role in tumour. However, the role and molecular mechanism of S100A11 in GBM are not clear. Here, we found that S100A11 was up-regulated in GBM tissues and higher S100A11 expression indicated poor prognosis of GBM patients. Overexpression of S100A11 promoted GBM cell growth, epithelial-mesenchymal transition (EMT), migration, invasion and generation of glioma stem cells (GSCs), whereas its knockdown inhibited these activities. More importantly, S100A11 interacted with ANXA2 and regulated NF-κB signalling pathway through decreasing ubiquitination and degradation of ANXA2. Additionally, NF-κB regulated S100A11 at transcriptional level as a positive feedback. We also demonstrated the S100A11 on tumour growth in GBM using an orthotopic tumour xenografting. These data demonstrate that S100A11/ANXA2/NF-κB positive feedback loop in GBM cells that promote the progression of GBM.

ERK1/2/mTOR/Stat3 pathway-mediated autophagy alleviates traumatic brain injury-induced acute lung injury.

Acute lung injury (ALI) is one of several complications in patients with traumatic brain injury (TBI). Autophagy is a primary homeostatic process that promotes cell survival under stress. Accumulating evidence implicates autophagy in the pathogenesis of ALI under various conditions. However, the role of autophagy in TBI-induced ALI remains unknown. The aim of this study was to adjust autophagy with pharmacological agents to determine its functional significance in TBI-induced ALI. Rats were preconditioned with autophagy promoter rapamycin or inhibitor 3-methyladenine before they were challenged with TBI. Extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor U0126, mechanistic target of rapamycin (mTOR) inhibitor rapamycin, and signal transducer and activator of transcription 3 (Stat3) inhibitor S31-201 were used to test the role of ERK1/2/mTOR/Stat3 signaling pathway in regulating autophagy. Autophagy is activated in lung tissues after TBI. Enhancement of autophagy suppressed apoptosis, inflammation and oxidative stress in lung tissues, which were activated after TBI, whereas inhibition of autophagy aggravated these critical pathological changes. Autophagy also improved TBI-induced impairment in pulmonary barrier function, oxygenation function and static compliance. Furthermore, TBI-induced autophagy was mediated by ERK1/2/mTOR/Stat3 pathway, which may serve to reduce ALI and improve pulmonary barrier function, oxygenation function and static compliance. These findings are important for the prevention and treatment of TBI-induced ALI.

Activation of bradykinin B2 receptor induced the inflammatory responses of cytosolic phospholipase A2 after the early traumatic brain injury.

Phospholipase A2 is a known aggravator of inflammation and deteriorates neurological outcomes after traumatic brain injury (TBI), however the exact inflammatory mechanisms remain unknown. This study investigated the role of bradykinin and its receptor, which are known initial mediators within inflammation activation, as well as the mechanisms of the cytosolic phospholipase A2 (cPLA2)-related inflammatory responses after TBI. We found that cPLA2 and bradykinin B2 receptor were upregulated after a TBI. Rats treated with the bradykinin B2 receptor inhibitor LF 16-0687 exhibited significantly less cPLA2 expression and related inflammatory responses in the brain cortex after sustaining a controlled cortical impact (CCI) injury. Both the cPLA2 inhibitor and the LF16-0687 improved CCI rat outcomes by decreasing neuron death and reducing brain edema. The following TBI model utilized both primary astrocytes and primary neurons in order to gain further understanding of the inflammation mechanisms of the B2 bradykinin receptor and the cPLA2 in the central nervous system. There was a stronger reaction from the astrocytes as well as a protective effect of LF16-0687 after the stretch injury and bradykinin treatment. The protein kinase C pathway was thought to be involved in the B2 bradykinin receptor as well as the cPLA2-related inflammatory responses. Rottlerin, a Protein Kinase C (PKC) δ inhibitor, decreased the activity of the cPLA2 activity post-injury, and LF16-0687 suppressed both the PKC pathway and the cPLA2 activity within the astrocytes. These results indicated that the bradykinin B2 receptor-mediated pathway is involved in the cPLA2-related inflammatory response from the PKC pathway.

MicroRNA-98 Attenuates Cell Migration and Invasion in Glioma by Directly Targeting Pre-B Cell Leukemia Homeobox 3.

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The extraordinary invasion of human GBM into adjacent normal brain tissues contributes to treatment failure. However, the mechanisms that control this process remain poorly understood. Increasing evidence has demonstrated that microRNAs are strongly implicated in the migration and invasion of GBM. In this study, we found that microRNA-98 (miR-98) was markedly downregulated in human glioma tissues and cell lines. Functional experiments indicated that restored expression of miR-98 attenuated glioma cell invasion and migration, whereas depletion of miR-98 promoted glioma cell invasion and migration. Subsequent investigation showed that pre-B-cell leukemia homeobox 3 (PBX3), an important transcription factor that controls tumor invasion, was a direct and functional target of miR-98 in GBM cells. Consistently, an orthotopic mouse model also demonstrated the suppressive effects of miR-98 overexpression on tumor invasion and PBX3 expression. Silencing of PBX3 using small interfering RNA inhibited the migratory and invasive capacities of glioma cells, whereas reintroduction of PBX3 into glioma cells reversed the anti-invasive function of miR-98. Furthermore, depletion of PBX3 phenocopied the effects of miR-98 overexpression in vivo. Finally, quantitative real-time polymerase chain reaction results showed that miR-98 was negatively correlated with PBX3 expression in 24 glioma tissues. Thus, we propose that PBX3 modulation by miR-98 has an important role in regulating GBM invasion and may serve as therapeutic target for GBM.