RAD52-mediated repair of DNA double-stranded breaks at inactive centromeres leads to subsequent apoptotic cell death.

Centromeres, where the kinetochore complex binds, are susceptible to damages including DNA double-stranded breaks (DSBs). Here, we report the functional significance and the temporally and spatially distinct regulation of centromeric DSB repair via the three pathways of non-homologous end joining (NHEJ), homologous recombination (HR) and single-strand annealing (SSA). The SSA factor RAD52 is most frequently recruited to centromeric DSB sites compared with the HR factor RAD51 and the NHEJ factor DNA ligase IV (LIG4), indicating that SSA plays predominant roles in centromeric DSB repair. Upon centromeric DSB induction, LIG4 is recruited to both active centromeres, where kinetochore complex binds, and inactive centromeres. In contrast, RAD51 and RAD52 are recruited only to inactive centromeres. These results indicate that DSBs at active centromeres are repaired through NHEJ, whereas the three pathways of NHEJ, HR and SSA are involved in DSB repair at inactive centromeres. Furthermore, siRNA-mediated depletion of either LIG4 or RAD51 promotes cell death after centromeric DSB induction, whereas RAD52 depletion inhibits it, suggesting that HR and NHEJ are required for appropriate centromeric DSB repair, whereas SSA-mediated centromeric DSB repair leads to subsequent cell death. Thus, SSA-mediated DSB repair at inactive centromeres may cause centromere dysfunction through error-prone repair.

Preoperative elevated E/e' (≥ 15) with preserved ejection fraction is associated with the development of postoperative heart failure in intermediate-risk non-cardiac surgical patients.

PURPOSE: Left ventricular diastolic dysfunction is an independent risk factor for adverse cardiovascular morbidities and mortalities in cardiovascular and high-risk surgical patients. However, there were only a few investigations among intermediate-risk surgical patients. This study aimed to investigate postoperative heart failure (HF) in intermediate-risk surgical patients who had preoperative diastolic dysfunction with preserved ejection fraction (EF). METHODS: Consecutive patients underwent intermediate-risk surgery between January 2016 and December 2018 were retrospectively evaluated. Patients with preserved EF were divided into three groups using one of the parameters of diastolic function: the ratio of early diastolic filling velocity to the peak diastolic velocity of mitral medial annulus (E/e') ≥ 15, E/e' between 8 and 15, and E/e' < 8. Postoperative HF was defined as clinical symptoms and radiological evidence and low SpO2 less than 93%. The primary outcome was the incidence of postoperative HF and its relation to preoperative E/e'. Chi-squared test, unpaired t test with Welch's correction, and multivariate logistic regression were used for analysis. RESULTS: In total, 965 patients were included in the final analysis. Postoperative HF developed in 36/965 (3.7%) patients with preserved EF. The incidence of postoperative HF was stratified according to the E/e', and the rates of HF occurrence in patients with E/e' < 8, 8-15, and ≥ 15 were 1.8%, 2.7%, and 15%, respectively (P < 0.01). CONCLUSION: Preoperative elevated E/e' (≥ 15) was associated with the development of postoperative HF in intermediate-risk surgical patients with preserved EF.

Inhibitory Effect of Pyra-Metho-Carnil on the Differentiation and Maturation of Macrophages in Normal and Cancer Microenvironments.

BACKGROUND/AIM: In a previous study, we have demonstrated heightened Pyra-Metho-Carnil (PMC) efficacy in nude mice with intact innate immunity that lack T and B cells. This has prompted hypothesizing that PMC may target macrophages that promote cancer growth. In this study, we conducted co-culture experiments with macrophages derived from THP-1 human monocyte cell lines and spheroids representing normal and cancer microenvironments. We then performed RNA sequencing and flow cytometry analysis to elucidate the mechanisms by which PMC affects macrophage differentiation and maturation. MATERIALS AND METHODS: THP-1 cells were differentiated by phorbol 12-myristate 13-acetate (PMA) and matured by PMA and lipopolysaccharide (LPS) either with or without PMC. Co-cultures were performed using stimulated THP-1 cells and HKe3-wild-type KRAS or HKe3-mutant (mt) KRAS spheroids. We then performed RNA-seq analysis of THP-1 cells stimulated by PMA (either with or without PMC) and flow cytometry analysis of mice peripheral blood obtained after PMC administration. RESULTS: THP-1 cells matured by PMA and LPS specifically increased the area of HKe3-mtKRAS cancer spheroids and the addition of PMC to THP-1 cells was found to inhibit cancer spheroid growth. RNA-seq data suggested that PMC treatment of THP-1 cells stimulated with PMA suppressed cell motility regulatory functions via down-regulation of the NF[Formula: see text]B pathway. Furthermore, flow cytometry results showed that PMC treatment suppressed monocyte maturation in B6 mice. CONCLUSION: The high level of in vivo tumor suppression caused by PMC may be due to inhibition of the differentiation and maturation of tumor-associated macrophages via the NF[Formula: see text]B signaling pathway.