The investigation of glutamate transporter 1 (GLT-1) degradation pathway in glioblastoma cells

Identification of immune-related molecular markers in intracranial aneurysm (IA) based on machine learning and cytoscape-cytohubba plug-in

BACKGROUND

Intracranial aneurysm (IA) is a common cerebrovascular disease. The immune mechanism of IA is more complicated, and it is unclear so far. Therefore, it is necessary to continue to explore the immune related molecular mechanism of IA.

METHODS

All data were downloaded from the public database. Limma package and ssGSEA algorithm was used to identify differentially expressed mRNAs (DEmRNAs) and analyze immune cell infiltration, respectively. Machine learning and cytoscape-cytohubba plug-in was used to identify key immune types and multicentric DEmRNAs of IA, respectively. Multicentric DEmRNAs related to key immune cells were screened out as key DEmRNAs by Spearman correlation analysis. Diagnostic models, competing endogenous RNA (ceRNA) regulatory network and transcription factor regulatory network were constructed based on key DEmRNAs. Meanwhile, drugs related to key DEmRNAs were screened out based on DGIdb database. The expression of key DEmRNAs was also verified by real time-PCR.

RESULTS

In this study, 7 key DEmRNAs (NRXN1, GRIA2, SLC1A2, SLC17A7, IL6, VEGFA and SYP) associated with key differential immune cell infiltration (CD56bright natural killer cell, Immature B cell and Type 1 T helper cell) were identified. Functional enrichment analysis showed that VEGFA and IL6 may be involved in the regulation of the PI3K-Akt signaling pathway. Moreover, IL6 was also found to be enriched in cytokine-cytokine receptor interaction signaling pathway. In the ceRNA regulatory network, a large number of miRNAs and lncRNAs were found. In the transcription factor regulatory network, the transcription factor SP1 was correlated with VEGFA, SYP and IL6. It is also predicted that drugs related to key DEmRNAs such as CARBOPLATIN, FENTANYL and CILOSTAZOL may contribute to the treatment of IA. In addition, it was also found that SVM and RF models based on key DEmRNAs may be potential markers for diagnosing IA and unruptured intracranial aneurysm (UIA), respectively. The expression trend of key DEmRNAs verified by real-time PCR was consistent with the bioinformatics analysis results.

CONCLUSION

The identification of molecules and pathways in this study provides a theoretical basis for understanding the immune related molecular mechanism of IA. Meanwhile, the drug prediction and diagnosis model construction may also be helpful for clinical diagnosis and management.

The expression of glutamate metabolism modulators in the intracranial tumors and glioblastoma cell line

BACKGROUND

The accumulation of excess glutamate in the synapse leads to excitotoxicity, which is the underlying reason of neuronal death in intracranial tumors.

METHODS AND RESULTS

We identified the expression levels of glutamate dehydrogenase, glutamine synthetase and sirtuin 4 in U87 cell line and various intracranial tumors. mRNA expressions of glutamate dehydrogenase (GDH), glutamine synthetase (GS) and sirtuin 4 (SIRT4) were analyzed in various intracranial tumors using qPCR. GDH, GS and SIRT4 protein expressions were analyzed in glioblastoma (U87) and glial (IHA-immortalized human astrocytes) cell lines via western blotting. The protein expressions of SIRT4 and GS were shown to be elevated and GDH protein expression was reduced in U87 cells in comparison to IHA cells. All types of intracranial tumors displayed lower GS mRNA expressions compared to controls. SIRT4 mRNA expressions were also shown to be lower in all the tumors and grades, although not significantly. GDH mRNA expression was found to be similar in all groups.

CONCLUSION

The molecular mechanisms of glutamate metabolism and excitotoxicity should be discovered to develop therapies against intracranial tumors.