Background: Although N6-methyladenosine (m6A) plays a very important role in different biological processes, its function in the brain has not been fully explored. Thus, we investigated the roles of the RNA demethylases Alkbh5/Fto in cerebral ischemia-reperfusion injury. Methods: We used a rat model and primary neuronal cell culture to study the role of m6A and Alkbh5/Fto in the cerebral cortex ischemic penumbra after cerebral ischemia-reperfusion injury. We used Alkbh5-shRNA and Lv-Fto ( in vitro) to regulate the expression of Alkbh5/Fto to study their regulation of m6A in the cerebral cortex and to study brain function after ischemia-reperfusion injury. Results: We found that RNA m6A levels increased consecutive to the increase of Alkbh5 expression in both the cerebral cortex of rats after middle cerebral artery occlusion, and in primary neurons after oxygen deprivation/reoxygenation. In contrast, Fto expression decreased after these perturbations. Our results suggest that knocking down Alkbh5 can aggravate neuronal damage. This is due to the demethylation of Alkbh5 and Fto, which selectively demethylate the Bcl2 transcript, preventing Bcl2 transcript degradation and enhancing Bcl2 protein expression. Conclusion: Collectively, our results demonstrate that the demethylases Alkbh5/Fto co-regulate m6A demethylation, which plays a crucial role in cerebral ischemia-reperfusion injury. The results provide novel insights into potential therapeutic mechanisms for stroke.
In lumbar posterior interbody fusion surgery, CaO-SiO-PO-BO glass ceramics spacer showed a similar fusion rates and clinical outcomes compared with titanium cage.
PurposeFeatures of epidermal growth factor receptor (EGFR) expression in osteosarcoma and in vitro efficacies of EGFR inhibitors against osteosarcoma cells were evaluated.Materials and MethodsThirty biopsy samples of osteosarcoma patients were retrospectively analyzed for EGFR protein expression by immunohistochemistry. Relationships between EGFR expression and clinicopathologic characteristics and treatment outcomes were evaluated. Four osteosarcoma cell lines were analyzed for EGFR and p-EGFR expression by western blotting. Efficacies of gefitinib and BIBW2992 on osteosarcoma cells were evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Tyrosine kinase domains in exons 18 to 21 were sequenced and gene expression analyses of EGFR and PTEN were performed in four osteosarcoma cell lines.ResultsEGFR protein was expressed in 27 (90%) samples (6 low, 12 intermediate, 9 high) and in three cell lines. Intermediate or high staining for EGFR was related to a tumor volume<150 mL (p<0.001) and histologic subtype other than osteoblastic type (p=0.03). However, EGFR expression was not associated with histologic response to preoperative chemotherapy or survival. Gefitinib and BIBW 2992 did not have any significant inhibitory effect on cell viabilities. DNA sequencing analysis revealed three osteosarcoma cell lines have single base changes at codon 2361 of exon 20 (G to A), without affecting translation results. Furthermore, no mutation was found to be associated with constitutive EGFR activation.ConclusionIn the present study, gefitinib and BIBW2992 were not effective against osteosarcoma cells. However, as osteosarcoma cells express EGFR, further studies are necessary to explore the potential of other therapeutic agents targeting EGFR.
Purpose This research aims to investigate the potential of 18 Ffluorodeoxyglucose positron emission tomography/computed tomography (FDG PET) to predict pathologic response after neoadjuvant chemotherapy (NAC) and overall survival (OS) of patients with synovial sarcoma in Korea. Methods Twenty patients with synovial sarcoma from January 2001 to December 2011 were reviewed retrospectively. All patients underwent pre-treatment FDG PET and tumor removal. Patients were classified with the maximum SUV (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), age, sex, histologic subtype, tumor size, NAC, resection margin, and metastasis at diagnosis. Pathologic response was assessed using the French Federation of Cancer Centers system. Statistical analyses were analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards regression model, and Mann-Whitney test. Results Nine patients (45 %) showed pathologic response, and ten patients survived. Higher SUVmax, higher MTV, higher TLG, monophasic epithelial type, and metastasis at diagnosis were significantly related to poorer OS (p=0.047, 0.016, 0.016, 0.045, and 0.018, respectively). By multivariate analysis, metastasis at diagnosis was significantly related to poorer OS (p=0.012/HR=5.9, 95 % CI 1.47 to 24.1). The SUVmax, MTV, and TLG of the non-responder group were significantly higher than those of the responder group (p= 0.020, 0.020, and 0.020, respectively). There was no significant difference in size between the two groups (p=0.062). Conclusions A higher SUVmax on the pre-treatment scan, monophasic epithelial type, and metastasis at diagnosis were significantly associated with a poorer OS, and pathologic responders showed a higher SUVmax before NAC. The PET parameters can be used to predict OS and pathologic response in patients with synovial sarcomas before NAC.
Previous studies have demonstrated that cardiomyocyte apoptosis, ferroptosis, and inflammation participate in the progress of sepsis-induced cardiomyopathy (SIC). Although Islet cell autoantigen 69 (ICA69) is an imperative molecule that could regulate inflammation and immune response in numerous illnesses, its function in cardiovascular disease, particularly in SIC, is still elusive. We confirmed that LPS significantly enhanced the expression of ICA69 in wild-type (WT) mice, macrophages, and cardiomyocytes. The knockout of ICA69 in lipopolysaccharide(LPS)-induced mice markedly elevated survival ratio and heart function, while inhibiting cardiac muscle and serum inflammatory cytokines, reactive oxygen (ROS), and ferroptosis biomarkers. Mechanistically, increased expression of ICA69 triggered the production of STING, which further resulted in the production of intracellular lipid peroxidation, eventually triggering ferroptosis and heart injury. Intriguingly, ICA69 deficiency only reversed the ferroptotic marker levels, such as prostaglandin endoperoxide synthase 2 (PTGS2), malonaldehyde (MDA), 4-hydroxynonenal (4HNE), glutathione peroxidase 4 (GPX4), superoxide dismutase (SOD), iron and lipid ROS, but had no effects on the xCT-dependent manner. Additionally, greater ICA69 level was identified in septic patients peripheralblood mononuclear cells (PBMCs) than in normal control groups. Generally, we unveil that ICA69 deficiency can relieve inflammation and ferroptosis in LPS-induced murine hearts and macrophages, making targeting ICA69 in heart a potentially promising treatment method for SIC.
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