Acquired resistance to KRAS G12C small-molecule inhibitors via genetic/nongenetic mechanisms in lung cancer.

Inherent or acquired resistance to sotorasib poses a substantialt challenge for NSCLC treatment. Here, we demonstrate that acquired resistance to sotorasib in isogenic cells correlated with increased expression of integrin ß4 (ITGB4), a component of the focal adhesion complex. Silencing ITGB4 in tolerant cells improved sotorasib sensitivity, while overexpressing ITGB4 enhanced tolerance to sotorasib by supporting AKT-mTOR bypass signaling. Chronic treatment with sotorasib induced WNT expression and activated the WNT/ß-catenin signaling pathway. Thus, silencing both ITGB4 and ß-catenin significantly improved sotorasib sensitivity in tolerant, acquired, and inherently resistant cells. In addition, the proteasome inhibitor carfilzomib (CFZ) exhibited synergism with sotorasib by down-regulating ITGB4 and ß-catenin expression. Furthermore, adagrasib phenocopies the combination effect of sotorasib and CFZ by suppressing KRAS activity and inhibiting cell cycle progression in inherently resistant cells. Overall, our findings unveil previously unrecognized nongenetic mechanisms underlying resistance to sotorasib and propose a promising treatment strategy to overcome resistance.

Characteristics of Phenolic Compounds in Peucedanum japonicum According to Various Stem and Seed Colors.

Total polyphenol and total flavonoid assays were performed to characterize the relationships between the color of Peucedanum japonicum (PJ) seed coat and stem and the content of phytochemical compounds. The samples were divided into two groups based on their stem and seed coat color, with each group containing 23 samples. The stem color group was subdivided into green, light red, and red, whereas the seed coat color group was divided into light brown, brown, and dark brown. In the stem color group, the light red stems exhibited the highest content of phytochemical compounds, with levels over 10% higher than those of the stems of the other colors. Moreover, among the top ten samples with the highest total polyphenol content, eight samples were light red, and the light red group also exhibited the highest total flavonoid content among the examined color groups. In terms of the seed coat color, the plants grown from dark brown seeds exhibited the highest contents of both total polyphenols and total flavonoids. In conclusion, PJ plants with dark brown seeds and light red stems contained the highest levels of phytochemical compounds. Collectively, our findings provide a valuable basis for future seed selection of PJ for pharmaceutical purposes.

Impact of Sodium Thiosulfate on Prevention of Nephrotoxicities in HIPEC: An Ancillary Evaluation of Cisplatin-Induced Toxicities in Ovarian Cancer.

PURPOSE: Hyperthermic intraperitoneal chemotherapy (HIPEC) with cisplatin confers a survival benefit in epithelial ovarian cancer (EOC) but is associated with renal toxicity. Sodium thiosulfate (ST) is used for nephroprotection for HIPEC with cisplatin, but standard HIPEC practices vary. METHODS: A prospective, nonrandomized, clinical trial evaluated safety outcomes of HIPEC with cisplatin 75 mg/m2 during cytoreductive surgery (CRS) in patients with EOC (n = 34) and endometrial cancer (n = 6). Twenty-one patients received no ST (nST), and 19 received ST. Adverse events (AEs) were reported according to CTCAE v.5.0. Serum creatinine (Cr) was collected preoperatively and postoperatively (Days 5-8). Progression-free survival (PFS) was followed. Normal peritoneum was biopsied before and after HIPEC for whole transcriptomic sequencing to identify RNAseq signatures correlating with AEs. RESULTS: Forty patients had HIPEC at the time of interval or secondary CRS. Renal toxicities in the nST group were 33% any grade AE and 9% grade 3 AEs. The ST group demonstrated no renal AEs. Median postoperative Cr in the nST group was 1.1 mg/dL and 0.5 mg/dL in the ST group (p = 0.0001). Median change in Cr from preoperative to postoperative levels were + 53% (nST) compared with - 9.6% (ST) (p = 0.003). PFS did not differ between the ST and nST groups in primary or recurrent EOC patients. Renal AEs were associated with downregulation of metabolic pathways and upregulation of immune pathways. CONCLUSIONS: ST significantly reduces acute renal toxicity associated with HIPEC with cisplatin in ovarian cancer patients. As nephrotoxicity is high in HIPEC with cisplatin, nephroprotective agents should be considered.

Acquired miR-142 deficit in leukemic stem cells suffices to drive chronic myeloid leukemia into blast crisis.

The mechanisms underlying the transformation of chronic myeloid leukemia (CML) from chronic phase (CP) to blast crisis (BC) are not fully elucidated. Here, we show lower levels of miR-142 in CD34+CD38- blasts from BC CML patients than in those from CP CML patients, suggesting that miR-142 deficit is implicated in BC evolution. Thus, we create miR-142 knockout CML (i.e., miR-142-/-BCR-ABL) mice, which develop BC and die sooner than miR-142 wt CML (i.e., miR-142+/+BCR-ABL) mice, which instead remain in CP CML. Leukemic stem cells (LSCs) from miR-142-/-BCR-ABL mice recapitulate the BC phenotype in congenic recipients, supporting LSC transformation by miR-142 deficit. State-transition and mutual information analyses of "bulk" and single cell RNA-seq data, metabolomic profiling and functional metabolic assays identify enhanced fatty acid ß-oxidation, oxidative phosphorylation and mitochondrial fusion in LSCs as key steps in miR-142-driven BC evolution. A synthetic CpG-miR-142 mimic oligodeoxynucleotide rescues the BC phenotype in miR-142-/-BCR-ABL mice and patient-derived xenografts.

Targeting ITGB4/SOX2-driven lung cancer stem cells using proteasome inhibitors.

This study investigates the role of integrin ß4 (ITGB4) and stemness-associated factor SOX2 in platinum resistance in lung squamous cell carcinoma (LUSC). The expression of SOX2 and ITGB4 is found to be high in all LUSC subtypes, but the impact of ITGB4 expression on overall patient survival varies by subtype. Cancer stem cells (CSCs) isolated from LUSC patients were found to be resistant to cisplatin, but knocking down ITGB4 or SOX2 sensitized them to cisplatin. Carfilzomib (CFZ) synergized with cisplatin and suppressed CSC growth by inhibiting ITGB4 and SOX2 expression. Additionally, CFZ was found to inhibit SOX2 expression epigenetically by inhibiting histone acetylation at the SOX2 promoter site. CFZ also suppressed the growth of SOX2-dependent small cell lung cancer cells in vitro and in vivo. The study highlights the unique function of CFZ as a transcriptional suppressor of SOX2, independent of its proteasome inhibitory function.

Characterization of Increased Extracellular Vesicle-Mediated Tigecycline Resistance in Acinetobacter baumannii.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is the most detrimental pathogen that causes hospital-acquired infections. Tigecycline (TIG) is currently used as a potent antibiotic for treating CRAB infections; however, its overuse substantially induces the development of resistant isolates. Some molecular aspects of the resistance mechanisms of AB to TIG have been reported, but they are expected to be far more complicated and diverse than what has been characterized thus far. In this study, we identified bacterial extracellular vesicles (EVs), which are nano-sized lipid-bilayered spherical structures, as mediators of TIG resistance. Using laboratory-made TIG-resistant AB (TIG-R AB), we demonstrated that TIG-R AB produced more EVs than control TIG-susceptible AB (TIG-S AB). Transfer analysis of TIG-R AB-derived EVs treated with proteinase or DNase to recipient TIG-S AB showed that TIG-R EV proteins are major factors in TIG resistance transfer. Additional transfer spectrum analysis demonstrated that EV-mediated TIG resistance was selectively transferred to Escherichia coli, Salmonella typhimurium, and Proteus mirabilis. However, this action was not observed in Klebsiella pneumonia and Staphylococcus aureus. Finally, we showed that EVs are more likely to induce TIG resistance than antibiotics. Our data provide direct evidence that EVs are potent cell-derived components with a high, selective occurrence of TIG resistance in neighboring bacterial cells.

Targeting fat mass and obesity-associated protein mitigates human colorectal cancer growth in vitro and in a murine model.

Introduction: Colorectal cancer (CRC) remains a significant cause of cancer related mortality. Fat mass and obesity-associated protein (FTO) is a m6A mRNA demethylase that plays an oncogenic role in various malignancies. In this study we evaluated the role of FTO in CRC tumorigenesis. Methods: Cell proliferation assays were conducted in 6 CRC cell lines with the FTO inhibitor CS1 (50-3200 nM) (± 5-FU 5-80 mM) and after lentivirus mediated FTO knockdown. Cell cycle and apoptosis assays were conducted in HCT116 cells (24 h and 48 h, 290 nM CS1). Western blot and m6A dot plot assays were performed to assess CS1 inhibition of cell cycle proteins and FTO demethylase activity. Migration and invasion assays of shFTO cells and CS1 treated cells were performed. An in vivo heterotopic model of HCT116 cells treated with CS1 or with FTO knockdown cells was performed. RNA-seq was performed on shFTO cells to assess which molecular and metabolic pathways were impacted. RT-PCR was conducted on select genes down-regulated by FTO knockdown. Results: We found that the FTO inhibitor, CS1 suppressed CRC cell proliferation in 6 colorectal cancer cell lines and in the 5-Fluorouracil resistant cell line (HCT116-5FUR). CS1 induced cell cycle arrest in the G2/M phase by down regulation of CDC25C and promoted apoptosis of HCT116 cells. CS1 suppressed in vivo tumor growth in the HCT116 heterotopic model (p< 0.05). Lentivirus knockdown of FTO in HCT116 cells (shFTO) mitigated in vivo tumor proliferation and in vitro demethylase activity, cell growth, migration and invasion compared to shScr controls (p< 0.01). RNA-seq of shFTO cells compared to shScr demonstrated down-regulation of pathways related to oxidative phosphorylation, MYC and Akt/ mTOR signaling pathways. Discussion: Further work exploring the targeted pathways will elucidate precise downstream mechanisms that can potentially translate these findings to clinical trials.

Thermodynamic Study of Am(III)-Isosaccharinate Complexation at Various Temperatures Implicating a Stepwise Reduction in Binding Denticity.

Isosaccharinic acid, a major final product of cellulose degradation under highly alkaline cement porewater conditions, is known to increase the mobility of actinides via strong complex formation. In this study, the formation of Am(III) complexes with α-d-isosaccharinate (ISA) was studied in terms of thermodynamics and coordination structures by combining spectrophotometry, time-resolved laser fluorescence spectroscopy (TRLFS), and density functional theory (DFT) calculations. The formation constants of the Am(III)-ISA complexes were determined by absorption spectroscopy at temperatures in the range of 15-70 °C. The measured reaction enthalpy and entropy changes indicate that the formation of a 1:1 Am(III)-ISA complex is driven by an increase in entropy. By contrast, the 1:2 complex formation is exothermic with a much less increase in entropy. DFT calculations predict that C2- and C4-hydroxyl groups, along with the carboxyl group, participate in the tridentate chelate binding of the primary ISA. The thermodynamic, TRLFS, and DFT results collectively suggest the tridentate binding of the primary ISA to Am(III) via a carboxylate and C2- and C4-hydroxyl groups in the protonated state and reduced dentate binding of the secondary ISA, such as bidentate binding, forming a four-membered ring structure via the carboxylate group.

A Nanocomposite with Extracellular Vesicles from Lactobacillus paracasei as a Bioinspired Nanoantibiotic Targeting Staphylococcus aureus.

The utilization of biomimetic materials that merge functional nanoparticles (NPs) with a cell-derived nanosized membrane is a state-of-the-art approach to harnessing cellular properties for biomedical applications. However, the development of biocompatible and species-selective biomimetic agents against hazardous pathogens threatening human health is still in its early stages. Herein, we report the synthesis and functional analysis of a novel nanoplatform in which a PEGylated MoS2-ZnO (MZ) nanocomposite was cloaked with a generally regarded as safe (GRAS)-grade Lactobacillus paracasei-derived extracellular vesicle (LPEV) for MZ-LPEV nanocomposite and evaluated its activity against Staphylococcus aureus. The MZ nanocomposite was characterized via X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The coating of MZ with LPEV was confirmed through nanoparticle tracking analysis and zeta potential measurements. MZ-LPEV exhibited 5- to 20-fold higher antibacterial activity than that of ZO NPs and MZ nanocomposite against S. aureus. Reactive oxygen species (ROS) production and bacterial membrane disruption were confirmed as antibacterial mechanisms of MZ-LPEV. Finally, MZ-LPEV exhibited enhanced biocompatibility and selectivity for S. aureus. All our results showed that LPEV could be utilized for developing synergistic nanoantibiotics against S. aureus.

Plant phenotype relationship corpus for biomedical relationships between plants and phenotypes.

Medicinal plants have demonstrated therapeutic potential for applicability for a wide range of observable characteristics in the human body, known as "phenotype," and have been considered favorably in clinical treatment. With an ever increasing interest in plants, many researchers have attempted to extract meaningful information by identifying relationships between plants and phenotypes from the existing literature. Although natural language processing (NLP) aims to extract useful information from unstructured textual data, there is no appropriate corpus available to train and evaluate the NLP model for plants and phenotypes. Therefore, in the present study, we have presented the plant-phenotype relationship (PPR) corpus, a high-quality resource that supports the development of various NLP fields; it includes information derived from 600 PubMed abstracts corresponding to 5,668 plant and 11,282 phenotype entities, and demonstrates a total of 9,709 relationships. We have also described benchmark results through named entity recognition and relation extraction systems to verify the quality of our data and to show the significant performance of NLP tasks in the PPR test set.

Hyperthermic Intraperitoneal Chemotherapy-Induced Molecular Changes in Humans Validate Preclinical Data in Ovarian Cancer.

PURPOSE: Hyperthermic intraperitoneal chemotherapy (HIPEC) confers a survival benefit in epithelial ovarian cancer (EOC) and in preclinical models. However, the molecular changes induced by HIPEC have not been corroborated in humans. PATIENTS AND METHODS: A feasibility trial evaluated clinical and safety outcomes of HIPEC with cisplatin during optimal cytoreductive surgery (CRS) in patients with EOC diagnosed with stage III, IV, or recurrent EOC. Pre- and post-HIPEC biopsies were comprehensively profiled with genomic and transcriptomic sequencing to identify mutational and RNAseq signatures correlating with response; the tumor microenvironment was profiled to identify potential immune biomarkers; and transcriptional signatures of tumors and normal samples before and after HIPEC were compared to investigate HIPEC-induced acute transcriptional changes. RESULTS: Thirty-five patients had HIPEC at the time of optimal CRS; all patients had optimal CRS. The median progression-free survival (PFS) was 24.7 months for primary patients and 22.4 for recurrent patients. There were no grade 4 or 5 adverse events. Anemia was the most common grade 3 adverse event (43%). Hierarchical cluster analyses identified distinct transcriptomic signatures of good versus poor responders to HIPEC correlating with a PFS of 29.9 versus 7.3 months, respectively. Among good responders, significant HIPEC-induced molecular changes included immune pathway upregulation and DNA repair pathway downregulation. Within cancer islands, % programmed cell death protein 1 expression in CD8+ T cells significantly increased after HIPEC. An exceptional responder (PFS 58 months) demonstrated the highest programmed cell death protein 1 increase. Heat shock proteins comprised the top differentially upregulated genes in HIPEC-treated tumors. CONCLUSION: Distinct transcriptomic signatures identify responders to HIPEC, and preclinical model findings are confirmed for the first time in a human cohort.

Repurposing of Ciclopirox to Overcome the Limitations of Zidovudine (Azidothymidine) against Multidrug-Resistant Gram-Negative Bacteria.

Multidrug-resistant (MDR) Gram-negative bacteria are the top-priority pathogens to be eradicated. Drug repurposing (e.g., the use of non-antibiotics to treat bacterial infections) may be helpful to overcome the limitations of current antibiotics. Zidovudine (azidothymidine, AZT), a licensed oral antiviral agent, is a leading repurposed drug against MDR Gram-negative bacterial infections. However, the rapid emergence of bacterial resistance due to long-term exposure, overuse, or misuse limits its application, making it necessary to develop new alternatives. In this study, we investigated the efficacy of ciclopirox (CPX) as an alternative to AZT. The minimum inhibitory concentrations of AZT and CPX against MDR Gram-negative bacteria were determined; CPX appeared more active against ß-lactamase-producing Escherichia coli, whereas AZT displayed no selectivity for any antibiotic-resistant strain. Motility assays revealed that ß-lactamase-producing Escherichia coli strains were less motile in nature and more strongly affected by CPX than a parental strain. Resistance against CPX was not observed in E. coli even after 25 days of growth, whereas AZT resistance was observed in less than 2 days. Moreover, CPX effectively killed AZT-resistant strains with different resistance mechanisms. Our findings indicate that CPX may be utilized as an alternative or supplement to AZT-based medications to treat opportunistic Gram-negative bacterial infections.

Wash-Free Amperometric Escherichia coli Detection via Rapid and Specific Proteolytic Cleavage by Its Outer Membrane OmpT.

Various methods have been developed for the detection of Escherichia coli (E. coli); however, they are complex and time-consuming. OmpT─a cell membrane endopeptidase of E. coli─strongly embedded in the outer membrane of only E. coli, exposed to external solutions, with high proteolytic activity, could be a suitable target molecule for the rapid and straightforward detection of E. coli. Herein, a wash-free, sensitive, and selective amperometric method for E. coli detection, based on rapid and specific proteolytic cleavage by OmpT, has been reported. The method involved (i) rapid proteolytic cleavage of consecutive amino acids, after cleavage by OmpT, linked to an electrochemical species (4-aminophenol, AP), by leucine aminopeptidase (LAP, an exopeptidase), (ii) affinity binding of E. coli on an electrode, and (iii) electrochemical-enzymatic (EN) redox cycling. OmpT cleaved the intermediate peptide bond of a peptide substrate containing alanine-arginine-arginine-leucine-AP (-A-R-R-L-AP), forming R-L-AP, followed by the cleavage of two peptide bonds of R-L-AP sequentially by LAP, to liberate an electroactive AP. Affinity binding and EN redox cycling, in addition to rapid proteolytic cleavage by OmpT and LAP, enabled high electrochemical signal amplification. Two-sequential-cleavage was employed for the first time in protease-based detection. The calculated detection limit for E. coli cells in tap water (approximately 103 CFU/mL after 1 h incubation) was lower than those obtained without affinity binding and EN redox cycling. The detection method was highly selective to E. coli as OmpT is present in only E. coli. High sensitivity, selectivity, and the absence of wash steps make the developed detection method practically promising.

Wash-Free, Sandwich-Type Protein Detection Using Direct Electron Transfer and Catalytic Signal Amplification of Multiple Redox Labels.

Direct electron transfer (DET) between a redox label and an electrode has been used for sensitive and selective sandwich-type detection without a wash step. However, applying DET is still highly challenging in protein detection, and a single redox label per probe is insufficient to obtain a high electrochemical signal. Here, we report a wash-free, sandwich-type detection of thrombin using DET and catalytic signal amplification of multiple redox labels. The detection scheme is based on (i) the redox label-catalyzed oxidation of a reductant, (ii) the conjugation of multiple redox labels per probe using a poly-linker, (iii) the low nonspecific adsorption of the conjugated poly-linker due to uncharged, reduced redox labels, and (iv) a facile DET using long, flexible poly-linker and spacer DNA. Amine-reactive phenazine ethosulfate and NADH were used as the redox label and reductant, respectively. N3-terminated polylysine was used as the poly-linker for the conjugation between an aptamer probe and multiple redox labels. Approximately 11 redox labels per probe and rapid catalytic NADH oxidation enable high signal amplification. Thrombin in urine could be detected without a wash step with a detection limit of ∼50 pM, which is practically promising for point-of-care testing of proteins.

Genomic Analysis of Cutaneous CD30-Positive Lymphoproliferative Disorders.

Primary cutaneous CD30+ T-cell lymphoproliferative disorders are the second most common cutaneous lymphomas. According to the World Health Organization, CD30+ T-cell lymphoproliferative disorders include primary cutaneous anaplastic large cell lymphoma (C-ALCL) and lymphomatoid papulosis (LyP) as well as borderline lesions. C-ALCL and LyP are thought to represent two ends of a spectrum of diseases that have different clinical presentations, clinical courses, and prognoses in their classic forms but share the same histology of medium to large CD30+ atypical lymphoid cell infiltrates. Because the behavior of these entities is different clinically and prognostically, we aim to search for oncogenic genomic variants using whole-exome sequencing that drive the development of LyP and C-ALCL. Clinical information, pathology, immunohistochemistry, and T-cell rearrangements on six cases of LyP and five cases of C-ALCL were reviewed to confirm the rendered diagnosis before whole-exome sequencing of all specimens. Both LyP and C-ALCL had recurrent alterations in epigenetic modifying genes affecting histone methylation and acetylation (SETD2, KMT2A, KMT2D, and CREBBP). However, they also harbor unique differences with mutations in signal transducer and activator of transcription gene STAT3 of the Jak/signal transducer and activator of transcription pathway and EOMES, a transcription factor involved in lymphocyte development, only noted in C-ALCL specimens. Genomic characterization of LyP and C-ALCL in this series confirms the role of multiple pathways involved in the biology and development of these lymphomatous processes. The identification of similar aberrations within the epigenetic modifying genes emphasizes common potential development mechanisms of lymphomagenesis within lymphoproliferative disorders being shared between LyP and C-ALCL; however, the presence of differences may account for the differences in clinical course.

Recent Advances in the Green Synthesis of Heterocycles: From Building Blocks to Biologically Active Compounds.

Recent advances in the environmentally benign synthesis of common heterocycles are described. This account features three main parts; the preparation of non-aromatic heterocycles, one-ring aromatic heterocycles and their condensed analogs. Due to the great variety of and high interest in these compounds, this work focuses on providing representative examples of the preparation of the target compounds.

Biomimetic Nanoparticles Coated with Bacterial Outer Membrane Vesicles as a New-Generation Platform for Biomedical Applications.

The biomedical field is currently reaping the benefits of research on biomimetic nanoparticles (NPs), which are synthetic nanoparticles fabricated with natural cellular materials for nature-inspired biomedical applications. These camouflage NPs are capable of retaining not only the physiochemical properties of synthetic nanoparticles but also the original biological functions of the cellular materials. Accordingly, NPs coated with cell-derived membrane components have achieved remarkable growth as prospective biomedical materials. Particularly, bacterial outer membrane vesicle (OMV), which is a cell membrane coating material for NPs, is regarded as an important molecule that can be employed in several biomedical applications, including immune response activation, cancer therapeutics, and treatment for bacterial infections with photothermal activity. The currently available cell membrane-coated NPs are summarized in this review. Furthermore, the general features of bacterial OMVs and several multifunctional NPs that could serve as inner core materials in the coating strategy are presented, and several methods that can be used to prepare OMV-coated NPs (OMV-NPs) and their characterization are highlighted. Finally, some perspectives of OMV-NPs in various biomedical applications for future potential breakthrough are discussed. This in-depth review, which includes potential challenges, will encourage researchers to fabricate innovative and improvised, new-generation biomimetic materials through future biomedical applications.

Colorimetric determination of phenolic compounds using peroxidase mimics based on biomolecule-free hybrid nanoflowers consisting of graphitic carbon nitride and copper.

Hybrid nanoflowers consisting of graphitic carbon nitride (GCN) and copper were successfully constructed without the involvement of any biomolecule, by simply mixing them at room temperature to induce proper self-assembly to achieve a flower-like morphology. The resulting biomolecule-free GCN-copper hybrid nanoflowers (GCN-Cu NFs) exhibited an apparent peroxidase-mimicking activity, possibly owing to the synergistic effect from the coordination of GCN and copper, as well as their large surface area, which increased the number of catalytic reaction sites. The peroxidase-mimicking GCN-Cu NFs were then employed in the colorimetric determination of selected phenolic compounds hydroquinone (HQ), methylhydroquinone (MHQ), and catechol (CC). For samples without phenolic compounds, GCN-Cu NFs catalyzed the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, producing an intense blue color signal. Conversely, in the presence of phenolic compounds, the oxidation of TMB was inhibited, resulting in a significant reduction of the color signal. Using this strategy, HQ, MHQ, and CC were selectively and sensitively determined in a linear range up to 100 µM with detection limits down to 0.82, 0.27, and 0.36 µM, respectively. The practical utility of this assay system was also validated by using it to detect phenolic compounds spiked in tap water, yielding a good recovery of 97.1-108.9% and coefficient of variation below 3.0%, demonstrating the excellent reliability and reproducibility of this strategy. Colorimetric determination of phenolic compounds using peroxidase mimics based on biomolecule-free hybrid nanoflowers consisting of graphitic carbon nitride and copper.

TDRD3 promotes DHX9 chromatin recruitment and R-loop resolution.

R-loops, which consist of a DNA/RNA hybrid and a displaced single-stranded DNA (ssDNA), are increasingly recognized as critical regulators of chromatin biology. R-loops are particularly enriched at gene promoters, where they play important roles in regulating gene expression. However, the molecular mechanisms that control promoter-associated R-loops remain unclear. The epigenetic 'reader' Tudor domain-containing protein 3 (TDRD3), which recognizes methylarginine marks on histones and on the C-terminal domain of RNA polymerase II, was previously shown to recruit DNA topoisomerase 3B (TOP3B) to relax negatively supercoiled DNA and prevent R-loop formation. Here, we further characterize the function of TDRD3 in R-loop metabolism and introduce the DExH-box helicase 9 (DHX9) as a novel interaction partner of the TDRD3/TOP3B complex. TDRD3 directly interacts with DHX9 via its Tudor domain. This interaction is important for recruiting DHX9 to target gene promoters, where it resolves R-loops in a helicase activity-dependent manner to facilitate gene expression. Additionally, TDRD3 also stimulates the helicase activity of DHX9. This stimulation relies on the OB-fold of TDRD3, which likely binds the ssDNA in the R-loop structure. Thus, DHX9 functions together with TOP3B to suppress promoter-associated R-loops. Collectively, these findings reveal new functions of TDRD3 and provide important mechanistic insights into the regulation of R-loop metabolism.

A New Surface Charge Neutralizing Nano-Adjuvant to Potentiate Polymyxins in Killing Mcr-1 Mediated Drug-Resistant Escherichia coli.

Resistance to polymyxins when treating multidrug-resistant (MDR) Gram-negative bacterial infections limit therapeutic options. Here, we report the synthesis of a nickel (Ni) doped Zinc oxide (NZO) combined with black phosphorus (BP) (NZB) nanocomposite and its synergistic action with polymyxin B (PolB) against polymyxin-resistant Escherichia coli harboring mobilized colistin resistance (mcr-1) gene. NZB and PolB combination therapy expressed a specific and strong synergy against Mcr-1 expressing E. coli cells. The underlying mechanism of the synergy is the charge neutralization of the E. coli cell surface by NZB, resulting in a more feasible incorporation of PolB to E. coli. The synergistic concentration of NZB with PolB was proved biocompatible. Thus, the NZB is the first biocompatible nano-adjuvant to polymyxins against polymyxin-resistant E. coli cells, recognizing the physical status of bacteria instead of known adjuvants targeting cellular gene products. Therefore, NZB has the potential to revive polymyxins as leading last-resort antibiotics to combat polymyxin-resistant Gram-negative bacterial infections.