Asparagine endopeptidase deficiency mitigates radiation-induced brain injury by suppressing microglia-mediated neuronal senescence.

Mounting evidence supports the role of neuroinflammation in radiation-induced brain injury (RIBI), a chronic disease characterized by delayed and progressive neurological impairment. Asparagine endopeptidase (AEP), also known as legumain (LGMN), participates in multiple malignancies and neurodegenerative diseases and may potentially be involved in RIBI. Here, we found AEP expression was substantially elevated in the cortex and hippocampus of wild-type (Lgmn+/+) mice following whole-brain irradiation. Lgmn knockout (Lgmn-/-) alleviated neurological impairment caused by whole-brain irradiation by suppressing neuronal senescence. Bulk RNA and metabolomic sequencing revealed AEP's involvement in the antigen processing and presentation pathway and neuroinflammation. This was further confirmed by co-culturing Lgmn+/+ primary neurons with the conditioned media derived from irradiated Lgmn+/+ or Lgmn-/- primary microglia. Furthermore, esomeprazole inhibited the enzymatic activity of AEP and RIBI. These findings identified AEP as a critical factor of neuroinflammation in RIBI, highlighting the prospect of targeting AEP as a therapeutic approach.

An integrated analysis of C5AR2 related to malignant properties and immune infiltration of gliomas.

Background: C5AR2 is recognized as a proinflammatory molecule and activates the inflammatory response in multiple disorders. However, little has been reported on C5AR2 in glioma. This study sought to explore its expression, biological function, and association with clinical pathological indicators, prognosis, and immune infiltration levels in glioma through glioma cohorts. Methods: A cohort of 657 patients was screened from the Chinese Glioma Genome Atlas (CGGA). χ 2 test was performed to calculate the difference of classified variables. Cox proportional hazard regression modeling was used to identify independent prognostic indicators of glioma patients. A survival plot was generated by the Kaplan-Meier method. The immune cell infiltration score of glioma patients was calculated by TIMER algorithm. Results: We observed that high expression of C5AR2 was strongly associated with malignant clinical indicators in 657 patients with glioma, and patients with high C5AR2 expression had worse prognoses. Multivariate Cox analysis showed that C5AR2 could be a new independent prognostic indicator for glioma patients. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that C5AR2 overexpression correlated with multiple inflammatory and immune biological processes. Additionally, high C5AR2 expression was strongly associated with higher abundance and marker gene expression of multiple tumor immune cells in low-grade glioma. Finally, a model was constructed to improve the prognostic evaluation of glioma patients. Conclusions: The C5AR2 gene is highly expressed in gliomas and is significantly associated with clinical indicators of malignant progression in glioma patients. In glioma, patients with high C5AR2 expression displayed a worse outcome. In glioma tissues, the expression level of C5AR2 highly correlated with the abundance of tumor immune cell infiltration. Additionally, GO and KEGG enrichment analysis revealed that C5AR2 expression may be involved in a variety of immune and inflammatory biological processes.

Upregulation of hsa-miR-196a-5p is associated with MIR196A2 methylation and affects the malignant biological behaviors of glioma.

Hsa-miR-196a-5p is involved in tumorigenesis and progression. However, the driving factors for hsa-miR-196a-5p overexpression and its correlation with the clinicopathological features and prognosis of patients remain unclear in glioma. Thus, this study aimed to investigate the prognostic value of hsa-miR-196a-5p and its correlation with MIR196A2 methylation in glioma. We observed that hsa-miR-196a-5p expression was upregulated in glioma. Next, 112 patients were divided into high (n = 56) and low (n = 56) hsa-miR-196a-5p expression groups. The chi-square test showed that hsa-miR-196a-5p expression was significantly related to age, WHO grade, histopathology, IDH mutation status, and 1p/19q codeletion. Univariate and multivariate Cox regression analyses showed that hsa-miR-196a-5p expression was an independent prognostic factor. GO and KEGG enrichment analyses showed that hsa-miR-196a-5p may be involved in the MAPK signaling, focal adhesion and cancer-related pathways. Compared with the normal astrocyte cell line, glioma cell lines had an unregulated MIR196A2 methylation level, which was confirmed by TCGA data. The hypermethylated CpG sites of MIR196A2 were mainly concentrated in the gene body region, which was significantly associated with hsa-miR-196a-5p overexpression. Kaplan-Meier curves revealed that MIR196A2 hypermethylation was a poor prognostic factor. These findings suggest that hsa-miR-196a-5p overexpression may be involved in malignant biological behaviors, and MIR196A2 hypermethylation of the gene body was significantly associated with hsa-miR-196a-5p overexpression, which was a poor prognostic factor of glioma. Therefore, MIR196A2 hypermethylation may act as an early marker of prognosis of patients with glioma.

Effect of Piezo1 Overexpression on Peritumoral Brain Edema in Glioblastomas.

BACKGROUND AND PURPOSE: Previous studies have suggested that increased mortality and disability in patients with brain tumor are associated with peritumoral brain edema. However, the mechanism of peritumoral brain edema in brain tumors is unknown. This study aimed to investigate the effect of Piezo1 overexpression on peritumoral brain edema in glioblastomas. MATERIALS AND METHODS: The Piezo1 expression in cell lines and paired samples was detected by quantitative reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Sixty-four patients with glioblastomas were analyzed retrospectively. The Piezo1 expression of tumor tissue was detected by immunohistochemistry. The diameters of tumor and edema were measured by preoperative MR imaging, and the edema index value was calculated. RESULTS: Western blot and quantitative reverse transcription polymerase chain reaction showed that Piezo1 expression was higher in 6 glioma cell lines than in the normal astrocyte cell line. Compared with peritumoral tissues, Piezo1 was up-regulated in tumor tissues. Sixty-four patients with glioblastomas were enrolled in further study. Piezo1 was higher in the moderate edema group than in the mild edema group (P < .001), higher in the severe edema group than in the moderate edema group (P < .001), and correlated with the edema index (r = 0.73; P < .001). Receiver operating characteristic curve analysis showed that the edema index yielded an area under the curve of 0.867 (95% CI, 0.76-0.97; P < .001), with a sensitivity of 100% and a specificity of 70%. CONCLUSIONS: Piezo1 overexpression is positively correlated with the degree of peritumoral brain edema in glioblastomas. Predicting high Piezo1 expression in tumor tissues based on the edema extent shows good sensitivity and specificity.