Atox1 protects hippocampal neurons after traumatic brain injury via DJ-1 mediated anti-oxidative stress and mitophagy.

Regulation of the oxidative stress response is crucial for the management and prognosis of traumatic brain injury (TBI). The copper chaperone Antioxidant 1 (Atox1) plays a crucial role in regulating intracellular copper ion balance and impacting the antioxidant capacity of mitochondria, as well as the oxidative stress state of cells. However, it remains unknown whether Atox1 is involved in modulating oxidative stress following TBI. Here, we investigated the regulatory role of Atox1 in oxidative stress on neurons both in vivo and in vitro, and elucidated the underlying mechanism through culturing hippocampal HT-22 cells with Atox1 mutation. The expression of Atox1 was significantly diminished following TBI, while mice with overexpressed Atox1 exhibited a more preserved hippocampal structure and reduced levels of oxidative stress post-TBI. Furthermore, the mice displayed notable impairments in learning and memory functions after TBI, which were ameliorated by the overexpression of Atox1. In the stretch injury model of HT-22 cells, overexpression of Atox1 mitigated oxidative stress by preserving the normal morphology and network connectivity of mitochondria, as well as facilitating the elimination of damaged mitochondria. Mechanistically, co-immunoprecipitation and mass spectrometry revealed the binding of Atox1 to DJ-1. Knockdown of DJ-1 in HT-22 cells significantly impaired the antioxidant capacity of Atox1. Mutations in the copper-binding motif or sequestration of free copper led to a substantial decrease in the interaction between Atox1 and DJ-1, with overexpression of DJ-1 failing to restore the antioxidant capacity of Atox1 mutants. The findings suggest that DJ-1 mediates the ability of Atox1 to withstand oxidative stress. And targeting Atox1 could be a potential therapeutic approach for addressing post-traumatic neurological dysfunction.

Meningioma achieves malignancy and erastin-induced ferroptosis resistance through FOXM1-AURKA-NRF2 axis.

The oncogene Aurora kinase A (AURKA) has been implicated in various tumor, yet its role in meningioma remains unexplored. Recent studies have suggested a potential link between AURKA and ferroptosis, although the underlying mechanisms are unclear. This study presented evidence of AURKA upregulation in high grade meningioma and its ability to enhance malignant characteristics. We identified AURKA as a suppressor of erastin-induced ferroptosis in meningioma. Mechanistically, AURKA directly interacted with and phosphorylated kelch-like ECH-associated protein 1 (KEAP1), thereby activating nuclear factor erythroid 2 related factor 2 (NFE2L2/NRF2) and target genes transcription. Additionally, forkhead box protein M1 (FOXM1) facilitated the transcription of AURKA. Suppression of AURKA, in conjunction with erastin, yields significant enhancements in the prognosis of a murine model of meningioma. Our study elucidates an unidentified mechanism by which AURKA governs ferroptosis, and strongly suggests that the combination of AURKA inhibition and ferroptosis-inducing agents could potentially provide therapeutic benefits for meningioma treatment.

O-GlcNAcylation of melanophilin enhances radiation resistance in glioblastoma via suppressing TRIM21 mediated ubiquitination.

The molecular mechanism of glioblastoma (GBM) radiation resistance remains poorly understood. The aim of this study was to elucidate the potential role of Melanophilin (MLPH) O-GlcNAcylation and the specific mechanism through which it regulates GBM radiotherapy resistance. We found that MLPH was significantly upregulated in recurrent GBM tumor tissues after ionizing radiation (IR). MLPH induced radiotherapy resistance in GBM cells and xenotransplanted human tumors through regulating the NF-κB pathway. MLPH was O-GlcNAcylated at the conserved serine 510, and radiation-resistant GBM cells showed higher levels of O-GlcNAcylation of MLPH. O-GlcNAcylation of MLPH protected its protein stability and tripartite motif containing 21(TRIM21) was identified as an E3 ubiquitin ligase promoting MLPH degradation whose interaction with MLPH was affected by O-GlcNAcylation. Our data demonstrate that MLPH exerts regulatory functions in GBM radiation resistance by promoting the NF-κB signaling pathway and that O-GlcNAcylation of MLPH both stabilizes and protects it from TRIM21-mediated ubiquitination. These results identify a potential mechanism of GBM radiation resistance and suggest a potential therapeutic strategy for GBM treatment.

Fetuin-A alleviates neuroinflammation against traumatic brain injury-induced microglial necroptosis by regulating Nrf-2/HO-1 pathway.

BACKGROUND: The microglia-mediated inflammatory response is a vital mechanism of secondary damage following traumatic brain injury (TBI), but the underlying mechanism of microglial activation is unclear. METHODS: Controlled cortical impact (CCI) was induced in adult male C57BL/6J mice, and glutamate was used to construct a classical in vitro injury model in the primary microglia. Microglial activation was determined by western blot and immunostaining. The inflammatory factors were measured by enzyme-linked immunosorbent assay. The oxidative stress marker and mitochondrial reactive oxygen species (ROS) were measured by immunoblotting and MitoSox Red staining. Transmission electron microscopy was used to observe the typical morphology of necroptotic cells. RESULTS: Our quantitative proteomics identified 2499 proteins; 157 were significantly differentially expressed in brain tissue between the 6 h after CCI (CCI6h) group and sham group, and 109 were significantly differentially expressed between the CCI24h and sham groups. Moreover, compared with the sham group, the terms "acute-phase response", "inflammation", and "protein binding" were significantly enriched in CCI groups. Fetuin-A, a liver-secreted acute-phase glycoprotein, was involved in these biological processes. Using an experimental TBI model, we found that the Fetuin-A level peaked at 6 h and then decreased gradually. Importantly, we showed that administration of Fetuin-A reduced the cortical lesion volume and edema area and inhibited the inflammatory response, which was associated with suppressing microglial necroptosis, thus decreasing microglial activation. Furthermore, administration of Fetuin-A attenuated mitochondrial oxidative stress in glutamate-treated microglial cells, which is a critical mechanism of necroptosis suppression. In addition, we demonstrated that Fetuin-A treatment promoted translocation of nuclear factor erythroid 2-related factor 2 (Nrf-2) from the cytoplasm to the nucleus in vivo; however, the Nrf-2 inhibitor ML385 and si-heme oxygenase-1 (si-HO-1) disrupted the regulation of oxidative stress by Fetuin-A and induced increased ROS levels and necroptosis in glutamate-treated microglial cells. Fetuin-A also protected neurons from adverse factors in vivo and in vitro. CONCLUSIONS: Our results demonstrated that Fetuin-A activated Nrf-2/HO-1, suppressed oxidative stress and necroptosis levels, and thereby attenuates the abnormal inflammatory response following TBI. The findings suggest a potential therapeutic strategy for TBI treatment.

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.

Prokineticin-2 prevents neuronal cell deaths in a model of traumatic brain injury.

Prokineticin-2 (Prok2) is an important secreted protein likely involved in the pathogenesis of several acute and chronic neurological diseases through currently unidentified regulatory mechanisms. The initial mechanical injury of neurons by traumatic brain injury triggers multiple secondary responses including various cell death programs. One of these is ferroptosis, which is associated with dysregulation of iron and thiols and culminates in fatal lipid peroxidation. Here, we explore the regulatory role of Prok2 in neuronal ferroptosis in vitro and in vivo. We show that Prok2 prevents neuronal cell death by suppressing the biosynthesis of lipid peroxidation substrates, arachidonic acid-phospholipids, via accelerated F-box only protein 10 (Fbxo10)-driven ubiquitination, degradation of long-chain-fatty-acid-CoA ligase 4 (Acsl4), and inhibition of lipid peroxidation. Mice injected with adeno-associated virus-Prok2 before controlled cortical impact injury show reduced neuronal degeneration and improved motor and cognitive functions, which could be inhibited by Fbxo10 knockdown. Our study shows that Prok2 mediates neuronal cell deaths in traumatic brain injury via ferroptosis.

Curcumin alleviates neuroinflammation, enhances hippocampal neurogenesis, and improves spatial memory after traumatic brain injury.

Cognitive decline is one of the most obvious symptoms of traumatic brain injury (TBI). Previous studies have demonstrated that cognitive decline is related to substantially increased neuroinflammation and decreased neurogenesis in the hippocampus in a rat model of TBI. Using this model, we explored the role of curcumin (Cur) in ameliorating TBI-impaired spatial memory because Cur has been shown to exhibit anti-chronic-neuroinflammatory, neurogenesis-promoting, and memory-improving properties. Animals received daily Cur or vehicle treatment for 28 days after TBI and also received 50-bromodeoxyuridine(BrdU) for the first 7 days of the treatment for assaying neurogenesis. An optimal Cur dose of 30 mg/kg, selected from a range of 10-50 mg/kg, was used for the present study. Neuroinflammation was evaluated by astrocyte hypertrophy, activated microglia, and inflammatory factors in the hippocampus. Behavioral water-maze studies were conducted for 5 days, starting at 35-day post-TBI. The tropomyosin receptor kinase B (Trkb) inhibitor, ANA-12, was used to test the role of the brain-derived neurotrophic factor (BDNF)/ TrkB/Phosphoinositide 3-kinase (PI3K)/Akt signaling pathway in regulating inflammation and neurogenesis in the hippocampus. Treatment with Cur ameliorated the spatial memory of TBI rats, reduced TBI-induced chronic inflammation, typified by diminished astrocyte hypertrophy, reduction in activated microglia, declined inflammatory factors, and increased neurogenesis in the hippocampus. We also found that BDNF/Trkb/PI3K/Akt signaling was involved in the effects of Cur in TBI rats. Thus, Cur treatment can ameliorate the spatial memory in a murine model of TBI, which may be attributable to decreased chronic neuroinflammation, increased hippocampal neurogenesis, and/or BDNF/Trkb/PI3K/Akt signaling.

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.

Smoothened Promotes Glioblastoma Radiation Resistance Via Activating USP3-Mediated Claspin Deubiquitination.

PURPOSE: Glioblastoma (GBM) is one of the most aggressive and lethal cancer types in humans. The standard treatment approach is surgery followed by chemoradiation. However, the molecular mechanisms of innate tumor radioresistance remain poorly understood. EXPERIMENTAL DESIGN: We tested the expression of Smoothened (Smo) in primary and recurrent GBM tissues and cells. Then, we determined radiation effectiveness against primary and recurrent GBM cells. Lastly, the functional role of Smo in GBM radioresistance was further confirmed by in vitro and in vivo experiments. RESULTS: We reported that Smo was significantly upregulated in recurrent GBM cell lines and tumor tissues following radiation treatment. Higher Smo expression indicated poor prognosis of GBM patients after radiation treatment. Smo had radioresistance effects in both GBM cells and human tumor xenografts. The mechanisms underlying these effects involved the attenuation of DNA damage repair caused by IR. Importantly, we found that the effect of Smo on radioresistance was mediated by Claspin polyubiquitination and proteasomal degradation, leading to the regulation of ATR-Chk1 signaling. Moreover, we found that Smo reduced Claspin polyubiquitination and proteasomal degradation by promoting USP3 transcription. Furthermore, we demonstrated that the Smo inhibitor GDC-0449 induced radiosensitivity to GBM. CONCLUSIONS: These data suggest that Smo confers radiation resistance in GBM by promoting USP3 transcription, leading to the activation of Claspin-dependent ATR-Chk1 signaling. These findings identify a potential mechanism of GBM resistance to radiation and suggest a potential therapeutic target for radiation resistance in GBM.

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.

Cardiac Myxoma: A Rare Case Series of 3 Patients and a Literature Review.

Myxoma is the most common tumor in the heart. A typical myxoma is relatively straightforward to diagnose. However, certain cardiac myxomas have rare features. We report three extremely rare cases of cardiac myxoma. One case involved a myxoma that originated from the annulus of the tricuspid after valvuloplasty, one case involved myxomas associated with left atrial thrombus and severe mitral stenosis, and the third case involved myxoma combined with severe calcification. All three cases were diagnosed by echocardiography and pathology. We also review clinical presentations and diagnostic characteristics of cardiac myxomas.

Polymorphisms of the 5-hydroxytryptamine 2A/2C receptor genes and 5-hydroxytryptamine transporter gene in Chinese patients with OSAHS.

BACKGROUND: It is known that there is a genetic predisposition to OSAHS. Polymorphisms of the 5-hydroxytryptamine (5-HT) 2A/2C receptors (5-HTR 2A/2C) genes and 5-HT transporter (5-HTT) gene may be associated with the pathogenesis of obstructive sleep apnea-hypopnea syndrome (OSAHS). OBJECTIVES: In this study, we aimed to investigate the prevalence of polymorphisms of the 5-HTR 2A/2C genes and the 5-HTT gene in the Chinese Han OSAHS population. METHODS: A total of 226 unrelated subjects of the Chinese Han population, including 121 OSAHS patients and 105 healthy controls, were involved in the study. The A1438G and T102C polymorphisms of the 5-HTR 2A gene, G796C polymorphisms of the 5-HTR 2C gene, and two polymorphisms (gene-linked polymorphic region [LPR] and variable number tandem repeat [VNTR]) of the 5-HTT gene were identified by polymerase chain reaction (PCR)-RFLP. RESULTS: Compared with the control group, the OSAHS group had significantly higher AA genotype and A allele frequencies in the A1438G polymorphisms of the 5-HTR 2A gene, and had significantly higher frequencies of 10/10, 12/10 genotypes and the allele 10 of 5-HTT-VNTR. There were no significant differences between the genotype distribution and allele frequencies of the OSAHS group and the control group regarding the T102C polymorphisms of the 5-HTR 2A gene and the G796C polymorphisms of the 5-HTR 2C gene, the frequencies of the S or L allele and the S/S, S/L or L/L genotypes in 5-HTT-LPR. CONCLUSIONS: The A1438G polymorphism of the 5-HTR 2A gene might be involved in the pathogenesis in OSAHS subjects of the Chinese Han population. Meanwhile, our findings support the argument that 5-HTT polymorphism appears to be associated with susceptibility to OSAHS, because the allele 10 of 5-HTT-VNTR might be a susceptible factor.