Causal association between mTOR-dependent EIF-4E and EIF-4A circulating protein levels and type 2 diabetes: a Mendelian randomization study.

The mammalian Target of Rapamycin complex 1 (mTORC1) nutrient-sensing pathway is a central regulator of cell growth and metabolism and is dysregulated in diabetes. The eukaryotic translation initiation factor 4E (EIF-4E) protein, a key regulator of gene translation and protein function, is controlled by mTORC1 and EIF-4E Binding Proteins (EIF4EBPs). Both EIF4EBPs and ribosomal protein S6K kinase (RP-S6K) are downstream effectors regulated by mTORC1 but converge to regulate two independent pathways. We investigated whether the risk of type 2 diabetes varied with genetically predicted EIF-4E, EIF-4A, EIF-4G, EIF4EBP, and RP-S6K circulating levels using Mendelian Randomization. We estimated the causal role of EIF-4F complex, EIF4EBP, and S6K in the circulation on type 2 diabetes, based on independent single nucleotide polymorphisms strongly associated (p = 5 × 10-6) with EIF-4E (16 SNPs), EIF-4A (11 SNPs), EIF-4G (6 SNPs), EIF4EBP2 (12 SNPs), and RP-S6K (16 SNPs). The exposure data were obtained from the INTERVAL study. We applied these SNPs for each exposure to publically available genetic associations with diabetes from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) case (n = 26,676) and control (n = 132,532) study (mean age 57.4 years). We meta-analyzed SNP-specific Wald-estimates using inverse variance weighting with multiplicative random effects and conducted sensitivity analysis. Mendelian Randomization (MR-Base) R package was used in the analysis. The PhenoScanner curated database was used to identify disease associations with SNP gene variants. EIF-4E is associated with a lowered risk of type 2 diabetes with an odds ratio (OR) 0.94, 95% confidence interval (0.88, 0.99, p = 0.03) with similar estimates from the weighted median and MR-Egger. Similarly, EIF-4A was associated with lower risk of type 2 diabetes with odds ratio (OR) 0.90, 95% confidence interval (0.85, 0.97, p = 0.0003). Sensitivity analysis using MR-Egger and weighed median analysis does not indicate that there is a pleiotropic effect. This unbiased Mendelian Randomization estimate is consistent with a protective causal association of EIF-4E and EIF-4A on type 2 diabetes. EIF-4E and EIF-4A may be targeted for intervention by repurposing existing therapeutics to reduce the risk of type 2 diabetes.

Application of CircEIF4G2 in Screening of Cervical Lesions.

BACKGROUND: The aim was to investigate the expression of circulating RNA EIF4G2 (CircEIF4G2) in cervical cancer and its correlation with clinicopathological features. METHODS: Cervical tissue and peripheral blood serum samples were collected from 148 patients with cervical lesions, including 30 patients with low-grade squamous intraepithelial lesions (LSIL group), 35 patients with high squamous intraepithelial lesion (HSIL group), 28 patients with atypical squamous cells (ASC group), and 55 patients with cervical cancer (CC group). At the same time, cervical biopsy specimens and peripheral blood serum were collected from 40 healthy women (Normal group). RT-PCR was used to detect the expression of CircEIF4G2 in cervical tissues and peripheral blood of each group. Electron microscopy was used to observe the distribution of exosomes CircEIF4G2 in cervical tissues. Meanwhile, the correlation between the expression level of CircEIF4G2 and clinical pathological data of patients was analyzed. In vitro, HeLa cells and primary cervical epithelial cells were cultured for 24 hours. Then, the expression levels of CircEIF4G2 in the two kinds of cells were detected by RT-PCR in medium. Furthermore, primary cervical epithelial cells were co-cultured with HeLa cells to observe the effect of exosome CircEIF4G2 on primary cervical epithelial cells. RESULTS: The expression of CircEIF4G2 in the cervical tissue and serum of the normal group was significantly lower than that in the CC group (p < 0.05), but there was no significant difference between the LSIL group and the HSIL group in the cervical tissue and serum (p < 0.05). The distribution and expression of exosomes CircEIF4G2 in each group were consistent with RT-PCR results under an electron microscope. The results of experiments in vitro showed that the expression level of CircEIF4G2 in HeLa cells was significantly higher than that in primary cervical epithelial cells (p < 0.05). The medium in which Hela cells were cultured for 24 hours was added to the culture medium of primary cervical epithelial cells. The process of exosomes CircEIF4G2 entering primary cervical cancer cells was observed by electron microscopy. CONCLUSIONS: The increased expression of CircEIF4G2 in tissues and serum of cervical lesions may be caused by the secretion of exosomes containing CircEIF4G2 by cervical cancer cells. Therefore, CircEIF4G2 can be used as a marker for the diagnosis of cervical lesions.