Downregulation of microRNA-124-3p promotes subventricular zone neural stem cell activation by enhancing the function of BDNF downstream pathways after traumatic brain injury in adult rats.

AIMS: In this study, the effect of intracerebral ventricle injection with a miR-124-3p agomir or antagomir on prognosis and on subventricular zone (SVZ) neural stem cells (NSCs) in adult rats with moderate traumatic brain injury (TBI) was investigated. METHODS: Model rats with moderate controlled cortical impact (CCI) were established and verified as described previously. The dynamic changes in miR-124-3p and the status of NSCs in the SVZ were analyzed. To evaluate the effect of lateral ventricle injection with miR-124-3p analogs and inhibitors after TBI, modified neurological severity scores (mNSSs) and rotarod tests were used to assess motor function prognosis. The variation in SVZ NSC marker expression was also explored. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of predicted miR-124-3p targets was performed to infer miR-124-3p functions, and miR-124-3p effects on pivotal predicted targets were further explored. RESULTS: Administration of miR-124 inhibitors enhanced SVZ NSC proliferation and improved the motor function of TBI rats. Functional analysis of miR-124 targets revealed high correlations between miR-124 and neurotrophin signaling pathways, especially the TrkB downstream pathway. PI3K, Akt3, and Ras were found to be crucial miR-124 targets and to be involved in most predicted functional pathways. Interference with miR-124 expression in the lateral ventricle affected the PI3K/Akt3 and Ras pathways in the SVZ, and miR-124 inhibitors intensified the potency of brain-derived neurotrophic factor (BDNF) in SVZ NSC proliferation after TBI. CONCLUSION: Disrupting miR-124 expression through lateral ventricle injection has beneficial effects on neuroregeneration and TBI prognosis. Moreover, the combined use of BDNF and miR-124 inhibitors might lead to better outcomes in TBI than BDNF treatment alone.

Acute and chronic infection of H. pylori caused the difference in apoptosis of gastric epithelial cells.

Helicobacter pylori (H. pylori) is one of the most important pathogenic bacteria associated with various gastrointestinal diseases. At present, its apoptotic or antiapoptotic mechanism on gastric epithelial cells remains unknown and needs further illustrated. In this study, acute infection model (H. pylori and GES-1 cells were co-cultured for 24 h at a multiplicity of infection MOI of 100:1) and chronic infection model (GES-1 cells were infected repeatedly every 24 h at a multiplicity of infection MOI of 100:1 for approximately 8 weeks) were established, respectively. the chronic H. pylori infected GES-1 cells underwent a typically morphological change and Western Blot results showed that there was slight decrease in expression of E-cadherin, and obvious increase in expression of Vimentin. Apoptosis of these two models were analyzed by flow cytometry compared with the control cells, meanwhile, apoptosis associated markers (Bcl-xL, Bcl-2, Bax, etc) were detected by Western blot, additional in clinical H. pylori-positive gastric cancer tissues. Results showed that compared with the control cells, acute infection of H. pylori significantly accelerated the apoptosis of GES-1, increased the expression of Bax and Cleaved caspase-3, down-regulated expression of Bcl-xL and Bcl-2. Moreover, an opposite result was found in chronic infection of model and clinical gastric cancer tissues, and enhanced expression of NF-κB p65. Taken together, these findings suggest that H. pylori infection plays differential effects on apoptosis of gastric epithelial cells.

The different role of YKL-40 in glioblastoma is a function of MGMT promoter methylation status.

Inter- and intratumoral heterogeneity is a hallmark of glioblastoma (GBM) that facilitates recurrence, treatment resistance, and worse prognosis. O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation is a significant prognostic marker for Temozolomide (TMZ) resistance in GBM patients. YKL-40 is a molecular marker for the mesenchymal subtype of GBMs and is responsible for TMZ resistance. However, underlying mechanisms by which MGMT epigenetics impacts patient outcomes and the function of YKL-40 are not fully determined. Herein, we performed in vitro and in vivo experiments, six human IDH1/2 wild-type glioblastoma stem-like cells (GSCs) were established and studied to further determine a potential interaction of YKL-40 and MGMT promoter methylation. We demonstrated that YKL-40 functioned differently in human IDH1/2 wild-type GSCs. In MGMT promoter-methylated (MGMT-m) GSCs, it acted as a tumor suppressor gene. On the other hand, in MGMT promoter-unmethylated (MGMT-um) GSCs, it promoted tumorigenesis. Notably, the reason that YKL-40 played different roles in GSCs could not be interpreted by the molecular classification of each GSCs, but is a function of MGMT promoter methylation status and involves the RAS-MEK-ERK pathway. YKL-40 mediated TMZ sensitivity by activating DNA damage responses (DDRs) in MGMT-m GSCs, and it mediated resistance to TMZ by inhibiting DDRs in MGMT-um GSCs. Our report demonstrated that MGMT promoter methylation status might influence a gene's function in human cancer. Moreover, our data also highlight the point that gene function should be investigated not only according to the molecular tumor classification, but also the epigenetic signature.

A five-CpG signature of microRNA methylation in non-G-CIMP glioblastoma.

AIMS: DNA methylation has been found to regulate microRNAs (miRNAs) expression, but the prognostic value of miRNA-related DNA methylation aberration remained largely elusive in cancers including glioblastomas (GBMs). This study aimed to investigate the clinical and biological feature of miRNA methylation in GBMs of non-glioma-CpG island methylator phenotype (non-G-CIMP). METHODS: Prognostic miRNA methylation loci were analyzed, with TCGA and Rennes cohort as training sets, and independent datasets of GBMs and low-grade gliomas (LGGs) were obtained as validation sets. Different statistical and bioinformatic analysis and experimental validations were performed to clinically and biologically characterize the signature. RESULTS: We identified and validated a risk score based on methylation status of five miRNA-associated CpGs which could predict survival of GBM patients in a series of training and validation sets. This signature was independent of age and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. The risk subgroup was associated with angiogenesis and accordingly differential responses to bevacizumab-contained therapy. MiRNA target analysis and in vitro experiments further confirmed the accuracy of this signature. CONCLUSION: The five-CpG signature of miRNA methylation was biologically relevant and was of potential prognostic and predictive value for GBMs. It might be of help for improving individualized treatment.