Loss of protein homeostasis is a hallmark of cellular senescence, and ribosome pausing plays a crucial role in the collapse of proteostasis. However, our understanding of ribosome pausing in senescent cells remains limited. In this study, we utilized ribosome profiling and G-quadruplex RNA immunoprecipitation sequencing techniques to explore the impact of RNA G-quadruplex (rG4) on the translation efficiency in senescent cells. Our results revealed a reduction in the translation efficiency of rG4-rich genes in senescent cells and demonstrated that rG4 structures within coding sequence can impede translation both in vivo and in vitro. Moreover, we observed a significant increase in the abundance of rG4 structures in senescent cells, and the stabilization of the rG4 structures further exacerbated cellular senescence. Mechanistically, the RNA helicase DHX9 functions as a key regulator of rG4 abundance, and its reduced expression in senescent cells contributing to increased ribosome pausing. Additionally, we also observed an increased abundance of rG4, an imbalance in protein homeostasis, and reduced DHX9 expression in aged mice. In summary, our findings reveal a novel biological role for rG4 and DHX9 in the regulation of translation and proteostasis, which may have implications for delaying cellular senescence and the aging process.
G-Quadruplexes ; Cellular Senescence ; Ribosomes/genetics* ; Humans ; Animals ; Mice ; DEAD-box RNA Helicases/genetics* ; Protein Biosynthesis ; RNA/chemistry* ; Neoplasm Proteins

Objective To analyze the risk factors for the occurrence of post transplantation diabetes mellitus (PTDM) in renal transplant recipients, establish a prediction model for PTDM and evaluate its prediction value. Methods Clinical data of 915 renal transplant recipients were retrospectively analyzed. According to the occurrence of PTDM, all recipients were divided into the PTDM group (n=78) and non-PTDM group (n=837). The main indexes of recipients were collected. The risk factors for the occurrence of PTDM in renal transplant recipients were analyzed by univariate and multivariate analysis. The prediction model for PTDM was established and its prediction value was evaluated. Results Family history of diabetes mellitus, body mass index (BMI), preoperative 2 h postprandial blood glucose and preoperative glycosylated hemoglobin were the independent risk factors for the occurrence of PTDM in renal transplant recipients. The prediction model for PTDM was logit (P)=2.199×family history of diabetes (yes=1, no=0)+0.109×BMI+0.151×2 h postprandial blood glucose (mmol/L)+0.508×glycosylated hemoglobin (%)-9.123. The results of receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) of these 4 predictors combined for predicting PTDM in renal transplant recipients was 0.830 [95% confidence interval (CI) 0.786-0.873], the cut-off value was 0.0608, the sensitivity was 0.821, the specificity was 0.700, and the Youden index was 0.521 (P < 0.05). Conclusions Family history of diabetes mellitus, BMI, preoperative 2 h postprandial blood glucose and preoperative glycosylated hemoglobin are the independent risk factors for the occurrence of PTDM in renal transplant recipients. The prediction model for PTDM combined with4 predictors yield relatively high prediction value for PTDM.