Exosomal miR-214-5p Released from Glioblastoma Cells Modulates Inflammatory Response of Microglia after Lipopolysaccharide Stimulation through Targeting CXCR5

Abstract

Background and Objective: Exosomes communicate inter-cellularly and miRNAs play critical roles in this scenario. MiR-214-5p was implicated in multiple tumors with diverse functions uncovered. However, whether miR-214-5p is mechanistically involved in glioblastoma, especially via exosomal pathway, is still elusive. Here we sought to comprehensively address the critical role of exosomal miR-214-5p in glioblastoma (GBM) microenvironment. Methods: The relative expression of miR-214-5p was determined by real-time PCR. Cell viability and migration were measured by MTT and transwell chamber assays, respectively. The secretory cytokines were measured with ELISA kits. The regulatory effect of miR-214-5p on CXCR5 expression was interrogated by luciferase reporter assay. Protein level was analyzed by Western blot. Results: We demonstrated that miR-214-5p was aberrantly overexpressed in GBM and associated with poorer clinical prognosis. High level of miR-214-5p significantly contributed to cell proliferation and migration. GBM-derived exosomal miR-214-5p promoted inflammatory response in primary microglia upon lipopolysaccharide challenge. We further identified CXCR5 as the direct target of miR-214- 5p in this setting. Conclusion: Overexpression of miR-214-5p in GBM modulated the inflammatory response in microglia via exosomal transfer.

Glioblastoma: Role of Mitochondria N-acetylserotonin/Melatonin Ratio in Mediating Effects of miR-451 and Aryl Hydrocarbon Receptor and in Coordinating Wider Biochemical Changes

“…It is also likely that this will impact on the contents of vesicles and exosomes produced by GBM/GSC, such as miRNAs, with consequences for regulation of glia and immune cells in the tumour microenvironment. 90 As such, alterations in the NAS/melatonin ratio have links to longstanding ideas regarding the nature of the tumour microenvironment and its influence on tumour survival, indicating that GBM/GSC may have a number of means in shaping this tumour microenvironment, including variations in the NAS/melatonin ratio. This suggests a dynamic 2-way interaction of tumour and tumour microenvironment, which would be modulated by levels of melatonin synthesis and uptake.…”

“…It is also likely that this will impact on the contents of vesicles and exosomes produced by GBM/GSC, such as miRNAs, with consequences for regulation of glia and immune cells in the tumour microenvironment. 90…”

Peritumoral Microenvironment in High-Grade Gliomas: From FLAIRectomy to Microglia–Glioma Cross-Talk

“…The GBM microenvironment, reshaped through these modifications, may contribute to tumor progression. Other evidence on the cross-talk between GBM and microglia comes from the finding reported by Yang et al; they demonstrated that miR-214-5p, aberrantly upregulated in GBM cells, can be transferred to microglia, through exosomes, contributing to the suppression of microglial C-X-C motif chemokine receptor 5 (CXCR5), and, consequently, increasing the microglial secretion of inflammatory cytokines IL-6, IL-8, and TNF-α, which, in turn, favor a tumorsupportive microenvironment [77]. The microglial function appears to be modulated also by miRNAs belonging to the let-7 family [78].…”

Extracellular Vesicle lncRNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Released From Glioma Stem Cells Modulates the Inflammatory Response of Microglia After Lipopolysaccharide Stimulation Through Regulating miR-129-5p/High Mobility Group Box-1 Protein Axis

“…Briefly, conditioned medium and precipitation solution were mixed (1:1) and incubated (4 • C, overnight), and then serially, centrifuges were performed (10,000 × g for 30 min; 140,000 × g for 5 min at 4 • C) to get the GSC supernatant and the resultant EV pellet, which was re-suspended with 250-500 µl cell medium. The equal volume of EVs derived from GSCs was added to the microglia cells for 48 h of consecutive culture (9).…”

“…Tumor-derived EVs may act on different types of immune cells, such as effector T cells, nature regulatory T cells, natural killer cells, and macrophages, which contributes to the induction and maintenance of the immune-suppression environment (7,8). Our previous data indicate that the EVs released from glioblastoma cells can transfer miR-214-5p to brain microglia/macrophages to modulate the corresponding inflammatory response that favors the survival of glioblastoma cells (9).…”