徐州医学院

Selective gene expression is pivotal in orchestrating human development. Specifically, trithorax group (TrxG) and polycomb group (PcG) components play crucial roles in transcriptional activation and repression of state-specific stem cell expression programs, yet the mechanisms underlying their selective genomic binding remain poorly understood. In this study, we report that the polycomb repressive complex 1 (PRC1) subunit RYBP co-localizes with TrxG component WDR5 and selectively enriches PcG component RING1B in condensates in murine embryonic stem cells (ESCs). RYBP deficiency impairs the genomic binding of WDR5 and RING1B. Further, STAT3 excludes RING1B binding at RYBP-associated transcriptionally active loci. Additionally, RYBP depletion attenuates WDR5-dependent activation of DNA repair gene expression and facilitates the transition of ESCs to 2-cell-like cells. Finally, RYBP depletion disrupts RING1B deposition at lineage-specific genes, promoting ESC differentiation towards mesendoderm fate. These findings uncover RYBP as a regulator of selective genomic binding of TrxG and PcG components, providing insights into their roles in cell fate determination during development.

Doxorubicin (DOX) is a cytotoxic chemotherapeutic drug, the clinical value of which is limited by its cardiotoxicity. Krüppel-like factor 9 (KLF9) is known to modulate cell proliferation, differentiation, and apoptosis and plays critical roles in cardiovascular diseases. Here, we aimed to explore the potential effect of KLF9 on DOX-induced cardiotoxicity. C57BL/6J mice with cardiac-specific overexpression or silencing of KLF9 received single intraperitoneal injections of DOX to establish a DOX-induced cardiotoxicity model. The cardiac function of the mice was monitored by echocardiography, cardiac morphology was evaluated by histopathological staining, biomarkers of myocardial injury were detected using ELISA, and TUNEL staining and Western blotting were performed to evaluate apoptosis. In addition, H9c2 cells were used to validate the function of KLF9 in vitro. To test the involvement of thioredoxin reductase 2 (Txnrd2), ROS and p53 in the observed effects, siRNAs directed against p53 and Txnrd2 and the ROS inhibitor N-acetyl cysteine (NAC) were used. KLF9 expression was upregulated in the hearts of DOX-treated mice and H9c2 cells. Cardiac-specific KLF9 overexpression exacerbated, while cardiac-specific KLF9 silencing alleviated, DOX-induced apoptosis, acute myocardial injury and dysfunction. Mechanistically, KLF9 deficiency resulted in upregulation of Txnrd2 expression and subsequent suppression of apoptosis through modulation by ROS/p53 signalling. KLF9 exerts a pro-apoptotic effect on DOX-induced cardiotoxicity by inhibiting Txnrd2 and regulating the ROS/p53 signalling pathway. KLF9 deficiency may be a promising target for mitigating DOX-induced cardiotoxicity.

Schizantherin B (SNB), a key bioactive ingredient of the Chinese traditional medicine Schisandra chinensis, possesses anti-inflammatory and antioxidant properties. Cisplatin (CDDP) is typically used to treat various malignant tumors, however, its clinical utility is often limited by significant off-target toxicities, most notably irreversible hearing loss. Various strategies have been explored to mitigate this side effect. In this study, we investigated the protective effects of SNB against cisplatin-induced hearing loss(CIHL) as a potential preclinical therapeutic strategy. Firstly, in the ex-vivo basilar membrane, we found that SNB alleviated CDDP-induced loss of hair cells, cochlear spiral ganglion cells, and ribbon synapses. Secondly, in vivo experiments showed that SNB protected animals against CHL, returning their response close to normal level. Thirdly, in multiple tumor cell lines, we found SNB did not interfere with CDDP’s anti-tumor effects. Consistently, in a mouse model for breast cancer, we found that SNB did not obtrude CDDP’s effects in reducing tumor mass. Finally, in examining the molecular mechanisms, we found that SNB reduced both oxidative stress and cell apoptosis in the auditory cell line of HEI-OC1 during CDDP treatment, likely through the Bcl-2/Bax/cleaved-Caspase-3 signal pathways. Collectively, our study demonstrated that SNB mitigates CIHL without interfering with its therapeutic effects in treating cancer, suggesting that SNB is a potential drug candidate for preventing CIHL in cancer patients.

Abstract Background Bacterial cancer therapies have regained attention as a strategy to remodel the immunosuppressive tumor microenvironment (TME). Engineered bacteria equipped with tumor-targeting moieties can enhance intratumoral specificity; however, safety concerns and the need for repeat dosing limit their translational potential. Methods Here, we developed an aptamer-conjugated engineered bacterial strain (ApCB) carrying CXCL9, and evaluated its tumor-targeting colonization and immunomodulatory effects in a subcutaneous LLC tumor model. After determining the in vitro minimum inhibitory concentration (MIC) of kanamycin and extrapolating an equivalent in vivo dose based on mouse blood volume, we implemented a tail-vein antibiotic administration strategy to precisely regulate intratumoral bacterial burden. Results Antibiotic treatment substantially lowered peak bacterial abundance in tumors while retaining a viable intratumoral bacterial reservoir, allowing sustained bacterial proliferation and periodic CXCL9 release without repeated re-administration of engineered bacteria. In vivo, ApCB–CXCL9 treatment significantly inhibited tumor growth, induced extensive tumor necrosis, decreased Ki67 expression, and increased intratumoral CD8⁺ T-cell infiltration together with elevated effector cytokines (IFN-γ, TNF-α). Conclusion These findings indicate that aptamer-guided engineered bacteria combined with antibiotic-mediated population control can safely and controllably remodel the tumor immune microenvironment, offering a practicable approach for sustained delivery and clinical translation of bacterial immunotherapies.

Myocardial ischemia/reperfusion (I/R) injury is a major cause of cardiac dysfunction, with ferroptosis playing a critical role. Transthyretin (TTR), a protein with neuroprotective and antioxidant properties, has been implicated in cardiovascular diseases. However, its specific role in myocardial I/R injury is unknown. This study explores the relationship between TTR and ferroptosis in myocardial I/R injury. The mice myocardial I/R models were established, after which transcriptomic RNA sequencing was performed to identify key genes. H9c2 cardiomyocytes underwent hypoxia/reoxygenation (H/R) treatment accompanied by siRNA-mediated knockdown of TTR. Cells were divided into control (Con), H/R, si-NC + H/R, and si-TTR + H/R groups. Ferroptosis markers were analyzed, including Fe²⁺ (colorimetric assay), ROS (flow cytometry), GSH, and lipid peroxidation (LPO). The levels of TFR1, SLC7A11, GPX4, and ACSL4 was measured by qRT-PCR and Western blot. Mitochondrial morphology was assessed via transmission electron microscopy. The Con group maintained normal cell viability, redox balance, and mitochondrial morphology. The H/R group exhibited ferroptosis-associated damage, including increased ROS, Fe²⁺, LPO, and TFR1/ACSL4 expression, along with decreased GSH, SLC7A11, and GPX4. TTR knockdown (si-TTR + H/R) mitigated these effects, restoring cellular homeostasis and improving mitochondrial integrity. TTR enhances ferroptosis during myocardial I/R injury. Its silencing protects cardiomyocytes by modulating iron metabolism, oxidative stress, and lipid peroxidation, making it a potential therapeutic target.