Ning Yu | PubMed Health

PubMed2026

Transketolase promotes RNF20-dependent H2BK120 ubiquitination and DNA repair through a non-enzymatic adaptor function.

Efficient repair of DNA double-strand breaks (DSBs) is essential for maintaining genome stability and conferring tumor radioresistance. Histone H2B monoubiquitination at lysine 120 (H2BK120ub), catalyzed by the RNF20/RNF40 E3 ligase complex, promotes DSB repair by coordinating chromatin remodeling and repair factor recruitment. Here we identify transketolase (TKT) as a non-enzymatic regulator of DNA damage repair in colorectal cancer cells. TKT enhances DNA repair efficiency and radioresistance independently of its catalytic activity by facilitating RNF20-dependent H2BK120ub. Mechanistically, TKT interacts with both the RNF20/RNF40 complex and the FACT chromatin remodeling complex, functioning as a non-enzymatic adaptor that facilitates FACT-RNF20 association and RNF20 foci formation following DNA damage. Disruption of this TKT-FACT-RNF20 axis impairs RNF20 foci formation and H2BK120ub induction, increases DNA damage, and enhances radiosensitivity. These findings reveal a previously unrecognized non-enzymatic adaptor function of TKT in DNA damage repair and highlight a potential vulnerability in radioresistant tumors.

DNA repair↗

PubMed2026

MiR-26a-5p/EZH2 Mediates Wnt2 Promoter Methylation to Regulate Trophoblast Dysfunction.

INTRODUCTION: Preeclampsia (PE) is a common complication of pregnancy, with a concomitant incidence rate of up to 10% among pregnant women worldwide. METHODS: In the current research, we explored the role and mechanism of miR-26a-5p in trophoblast function using CCK-8, colony formation assay, and flow cytometry. The interaction between miR-26a-5p and EZH2 was analyzed using a luciferase reporter assay. Methylationspecific PCR was performed to detect the methylation level of Wnt2 in HTR8 cells. RESULTS: Wnt2 and miR-26a-5p promoted the proliferation and inhibited the apoptosis in trophoblasts (P<0.05). The secretion of inflammatory cytokines was suppressed by Wnt2 and miR-26a-5p (P<0.05). EZH2 was identified as a regulatory target of miR-26a-5p using HTR8 cells and bioinformatic tools. miR-26a-5p inhibited expression through direct binding to EZH2. Importantly, miR- 26a-5p mediated DNA methylation of Wnt2 to regulate Wnt2 expression in HTR8 cells. DISCUSSION: This study elucidates a novel regulatory axis that alleviates trophoblast dysfunction by promoting proliferation and suppressing inflammation and apoptosis. The findings reveal that the miR-26a-5p/EZH2/Wnt2 pathway, potentially involving promoter methylation, is crucial for maintaining trophoblast function. This work identifies a promising therapeutic target for PE, although further in vivo validation is required to confirm its clinical potential. CONCLUSION: It was found that miR-26a-5p increased the expression of Wnt2 by downregulating EZH2. Moreover, miR-26a-5p/EZH2/Wnt2 promoted the proliferation and inhibited the inflammation and apoptosis in trophoblasts. This research provides insight into the role of miR-26a- 5p/EZH2/Wnt2 as a novel indicator for the prevention and treatment of PE.

MicroRNAs↗