Comprehensive investigation of malignant epithelial cell-related genes in clear cell renal cell carcinoma: development of a prognostic signature and exploration of tumor microenvironment interactions.

Clear cell renal cell carcinoma (ccRCC) is a prevalent malignancy with complex heterogeneity within epithelial cells, which plays a crucial role in tumor progression and immune regulation. Yet, the clinical importance of the malignant epithelial cell-related genes (MECRGs) in ccRCC remains insufficiently understood. This research aims to undertake a comprehensive investigation into the functions and clinical relevance of malignant epithelial cell-related genes in ccRCC, providing valuable understanding of the molecular mechanisms and offering potential targets for treatment strategies. Using data from single-cell sequencing, we successfully identified 219 MECRGs and established a prognostic model MECRGS (MECRGs' signature) by synergistically analyzing 101 machine-learning models using 10 different algorithms. Remarkably, the MECRGS demonstrated superior predictive performance compared to traditional clinical features and 92 previously published signatures across six cohorts, showcasing its independence and accuracy. Upon stratifying patients into high- and low-MECRGS subgroups using the specified cut-off threshold, we noted that patients with elevated MECRGS scores displayed characteristics of an immune suppressive tumor microenvironment (TME) and showed worse outcomes after immunotherapy. Additionally, we discovered a distinct ccRCC tumor cell subtype characterized by the high expressions of PLOD2 (procollagen-lysine,2-oxoglutarate 5-dioxygenase 2) and SAA1 (Serum Amyloid A1), which we further validated in the Renji tissue microarray (TMA) cohort. Lastly, 'Cellchat' revealed potential crosstalk patterns between these cells and other cell types, indicating their potential role in recruiting CD163 + macrophages and regulatory T cells (Tregs), thereby establishing an immunosuppressive TME. PLOD2 + SAA1 + cancer cells with intricate crosstalk patterns indeed show promise for potential therapeutic interventions.

The effect of probiotics supplementation on cancer-treatment complications: a critical umbrella review of interventional meta-analyses.

Cancer-related complications pose significant challenges in the management and treatment of patients with malignancies. Several meta-analyses have indicated improving effects of probiotics on cancer complications, while some studies have reported contentious findings. The purpose of the present study was to evaluate the efficacy of probiotics in addressing cancer complications, including diarrhea, mucositis, and infections, following chemotherapy, radiotherapy, and surgery. Relevant studies were searched in the PubMed, Scopus, Embase and Web of Science databases and Google Scholar up to September 2023. All meta-analyses addressing the effects of probiotics on all cancer treatments-induced complications including infection, diarrhea and oral mucositis were included. The pooled results were calculated using a random-effects model. Analyses of subgroups, sensitivity and publication bias were also conducted. The results revealed that the probiotics supplementation was effective on reduction of total cancer complications (OR:0.53; 95% CI: 0.44, 0.62, p < 0.001; I2=79.0%, p < 0.001), total infection rate (OR:0.47; 95%CI: 0.41, 0.52, p < 0.001; I2= 48.8%, p < 0.001); diarrhea (OR:0.50; 95%CI: 0.44, 0.57, p < 0.001; I2=44.4%, p = 0.023) and severe diarrhea (OR: 0.4; 95%CI: 0.27, 0.56, p < 0.001; I2=31.3%, p = 0.178), oral mucositis (OR: 0.76; 95%CI: 0.58, 0.94, p < 0.001; I2=95.5%, p < 0.001) and severe oral mucositis (OR:0.65, 95%CI: 0.58, 0.72 p < 0.001; I2=22.1%, p = 0.274). Multi strain probiotic (OR:0.49; 95%CI: 0.32, 0.65, p < 0.001; I2=90.7%, p < 0.001) were more efficacious than single strain (OR:0.73; 95%CI: 0.66, 0.81, p < 0.001; I2=0.00%, p = 0.786). The findings of the current umbrella meta-analysis provide strong evidence that probiotic supplementation can reduce cancer complications.

Case Report of Severe Chlamydia psittaci Pneumonia Treated with Omadacycline.

The clinical severity of Chlamydia psittaci infection ranges from asymptomatic to severe pneumonia. Diagnosis poses challenges due to its similarity to other respiratory infections. Treatment includes tetracyclines, macrolides, and fluoroquinolones, with limited evidence on the efficacy of omadacycline. We report a case of an 86-year-old male with severe psittacosis treated with omadacycline, resulting in significant improvement. This highlights the necessity for further research on omadacycline's role in psittacosis treatment.

Reactivation Risk of Latent Tuberculosis or Inactive Hepatitis B Virus Infection and Effectiveness of Ustekinumab in Chinese Plaque Psoriasis Patients: A 28-Week Retrospective, Observational Study.

Introduction: This study observed the effectiveness of ustekinumab and reactivation risk of concurrent latent tuberculosis infection (LTBI) and inactive hepatitis B virus (HBV) infection in Chinese mainland psoriasis patients on ustekinumab treatment. Methods: This retrospective, multicenter, observational study was conducted in three centers in China. Adult patients with moderate to severe plaque psoriasis were treated with ustekinumab for 28 weeks. The effectiveness endpoint included 75% and 90% improvement in Psoriasis Area Severity Index (PASI75/90) response rate, percentage of PASI improvement, change of absolute PASI score and body surface area involvement (BSA) score, absolute PASI ≤1/3 and Physicians' Global Assessment (PGA)=0/1, as well as Dermatology life quality index (DLQI)=0/1 response rate at week 4, 16 and 28. Screening of tuberculosis and hepatitis were performed at baseline and week 28. Results: A total of 82 patients were enrolled between March 2021 and May 2023 and the number of patients combined with LTBI and inactive HBV infection was 20 and 21 respectively. The PASI75 and PASI90 response rate at week 28 was 95.1% and 81.7% respectively. The mean PASI score decreased from 14.93 ± 12.07 at baseline to 0.78 ± 1.86 at week 28, and the mean BSA score decreased from 21% ± 18% at baseline to 1% ± 2% at week 28 (both P<0.001 compared with baseline). DLQI 0/1 response rate at week 28 was 73.2%. No reactivation of LTBI and inactive HBV infection and also no new-onset tuberculosis and hepatitis B occurred in patients without LTBI and inactive HBV infection at baseline. Conclusion: Ustekinumab demonstrated great effectiveness in Chinese plaque psoriasis patients and good safety in psoriasis concurrent with LTBI and inactive HBV infection under the real-world setting.

The first mitochondrial genome of Meroplius fukuharai (Diptera: Sepsidae).

Meroplius fukuharai is an important sanitary and ecological resource insect. We sequenced and annotated the mitogenome of Meroplius fukuharai which is the first representative of the genus Meroplius with nearly complete mitochondrial data. This mitogenome is 14,803 bp long, which consists of 22 transfer RNA genes, 13 protein-coding genes (PCGs), and two ribosomal RNA genes. All genes have a conservational arrangement with other published species of Sepsidae. Our results also supported the monophyly of Sepsidae, and the genus Meroplius is more closely related to genus Sepsis, Microsepsis, and Archisepsis.

Red wine alleviates atherosclerosis-related inflammatory markers in healthy subjects rather than in high cardiovascular risk subjects: A systematic review and meta-analysis.

BACKGROUND: Moderate red wine (RW) consumption is associated with a low risk of cardiovascular disease (CVD). However, few studies have evaluated the effects of RW and white wine (WW) on inflammatory markers related to atherosclerosis in healthy individuals and high-risk subjects for CVD. This study aimed to assess the effect of RW on inflammatory markers in healthy individuals and high-risk subjects for CVD compared with moderate alcohol consumption. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA) was followed in this study. The PubMed, Embase, Cochrane, Web of Science, SinoMed, EbscoHost, and ScienceDirect databases were searched. The risk of bias and quality of the included trials were assessed using the Cochrane Handbook. The main results are summarized in Stata 12. RESULTS: Twelve studies were included in the meta-analysis. The results demonstrated that RW significantly decreased circulating intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor-alpha (TNF-α), lymphocyte function-associated antigen-1, and Sialyl-Lewis X expression on the surface of monocytes in healthy subjects, but not in patients with CVD. Additionally, RW significantly decreased Sialyl-Lewis X but increased clusters of differentiation 40 (CD40) expressed on the surface of T lymphocytes and significantly decreased C-C chemokine receptor type 2 (CCR2) and very late activation antigen 4 (VLA-4) expressed on the surface of monocytes. Interestingly, subgroup analysis also found that RW significantly decreased circulating interleukin-6 (IL-6) in Spain but not in other countries, and significantly increased αMß2 (Mac-1) in the group that had an intervention duration of less than 3 weeks. CONCLUSIONS: Moderate consumption of RW is more effective than WW in alleviating atherosclerosis-related inflammatory markers in healthy people rather than high-risk subjects for CVD, but this needs to be further confirmed by studies with larger sample sizes.

Identification of nuclear membrane SUN proteins and components associated with wheat fungal stress responses.

In eukaryotes, the nuclear membrane that encapsulates genomic DNA is composed of an inner nuclear membrane (INM), an outer nuclear membrane (ONM), and a perinuclear space. SUN proteins located in the INM and KASH proteins in the ONM form the SUN-KASH NM-bridge, which functions as the junction of the nucleocytoplasmic complex junction. Proteins containing the SUN domain showed the highest correlation with differentially accumulated proteins (DAPs) in the wheat response to fungal stress. To understand the characteristics of SUN and its associated proteins in wheat responding to pathogen stress, here we investigated and comprehensive analyzed SUN- and KASH-related proteins among the DAPs under fungi infection based on their conserved motifs. In total, four SUN proteins, one WPP domain-interacting protein (WIP), four WPP domain-interacting tail-anchored proteins (WIT), two WPP proteins and one Ran GTPase activating protein (RanGAP) were identified. Following transient expression of Nicotiana benthamiana, TaSUN2, TaRanGAP2, TaWIT1 and TaWIP1 were identified as nuclear membrane proteins, while TaWPP1 and TaWPP2 were expressed in both the nucleus and cell membrane. RT-qPCR analysis demonstrated that the transcription of TaSUN2, TaRanGAP2 and TaWPP1 were strongly upregulated in response to fungal infection. Furthermore, using the bimolecular fluorescence complementation, the luciferase complementation and a nuclear and split-ubiquitin-based membrane yeast two-hybrid systems, we substantiated the interaction between TaSUN2 and TaWIP1, as well as TaWIP1/WIT1 and TaWPP1/WPP2. Silencing of TaSUN2, TaRanGAP2 and TaWPP1 in wheat leaves promoted powdery mildew infection and hyphal growth, and reduced the expression of TaBRI1, TaBAK1 and Ta14-3-3, indicating that these NM proteins play a positive role in resistance to fungal stress. Our study reveals the characteristics of NM proteins and propose the preliminary construction of SUN-WIP-WPP-RanGAP complex in wheat, which represents a foundation for detail elucidating their functions in wheat in future.

Integrative study of transcriptome and microbiome to reveal the response of Rhododendron decorum to cadmium stress.

The anomalies of cadmium (Cd) in karst region pose a severe threat to plant growth and development. In this study, the responses of Rhododendron decorum to Cd stress were investigated at physiological, molecular, and endophytic microbial levels, and the potential correlation among these responses was assessed. The Cd stress impeded R. decorum growth and led to an increase in malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels, as well as enhanced superoxide dismutase (SOD) and catalase (CAT) activities. Meanwhile, Cd stress increased the Cd (up to 80 times compared to the control), sodium (Na), aluminum (Al), and zinc (Zn) contents, while decreased the magnesium (Mg) and manganese (Mn) contents in R. decorum leaves. Transcriptome suggested that Cd significantly regulated the pathways including "protein repair", "hormone-mediated signaling pathway", and "ATP-binding cassette (ABC) transporters". Additionally, q-PCR analysis showed that Cd stress significantly up-regulated the expressions of ABCB19-like and pleiotropic drug resistance, while down-regulated the expressions of indole-3-acetic acid-amido synthetase and cytokinin dehydrogenase. The Cd stress influenced the composition of endophytic microbial communities in R. decorum leaves and enhanced the interspecific bacterial associations. Furthermore, the bacterial genera Achromobacter, Aureimonas and fungal genus Vishniacozyma exhibited a high degree of connectivity with other nodes in networks constructed by the metal element contents, differentially expressed genes (DEGs), and microbial communities, respectively. These findings provide a comprehensive insight into the response of R. decorum to Cd-induced stress, which might facilitate the breeding of the Cd-tolerant R. decorum.

Multi-Mode Luminescence in Smart Near-Infrared Cr3+/Pr3+ Codoped SrGa12O19 Phosphors Induced by Three Distinct Excitation Mechanisms.

Near-infrared (NIR) phosphors have emerged as novel luminescent materials across various fields due to their unique advantages of high penetration and invisibility. However, there is currently a lack of intelligent NIR phosphors that can achieve multimode stimuli responsive for sensing applications. In this study, we employed a high-temperature solid-phase reaction to incorporate Pr3+ into Cr3+-doped gallate magnetite SrGa12O19 phosphor, yielding a multimode luminescent intelligent NIR phosphor. Also, due to the inherent cation vacancies and defects in the matrix, the material not only exhibits brighter photoluminescence but also exhibits distinct NIR mechanoluminescence at a lower load. Notably, Pr3+-doped SrGa12O19:Cr3+ also demonstrates extended persistent luminescence and thermoluminescence effects. Finally, we combined the phosphor with the blue LED chip to develop a new multifunctional NIR pc-LED. Leveraging NIR's unique penetrating ability, it can persist in biological tissues for prolonged periods, enabling optical inspection and offering a novel approach to password protection for anticounterfeiting measures. This intelligent NIR phosphor solution significantly expands the application potential of NIR light in food quality assessment and analysis.

Laurocapram, a transdermal enhancer, boosts cephalosporin's antibacterial activity against Methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA), a notorious bacterium with high drug resistance and easy recurrence after surgery, has posed significant clinical treatment challenges. In the current scarcity of new antibiotics, the identification of adjuvants to existing antibiotics is a promising approach to combat infections caused by multidrug-resistant Gram-positive bacteria. The in vitro synergy test, which included a MIC assay, time-kill curve, antimicrobial susceptibility testing, and live/dead bacteria staining assay, revealed that laurocapram, a widely used chemical transdermal enhancer, could potentiate the antibacterial activity of cephalosporins against MRSA. In vitro, laurocapram combined with cefixime showed an excellent synergistic activity against MRSA (FICI = 0.28 ± 0.00). In addition, the combination of laurocapram and cefixime may inhibited the formation of MRSA biofilm and caused cell membrane damage. Following that, we discovered that combining laurocapram with cefixime could alleviate the symptoms of mice in the MRSA skin infection model and the MRSA pneumonia model. In conclusion, laurocapram is a promising and low-cost antibacterial adjuvant, providing a new strategy for further exploring the use of lower doses of cephalosporins to combat MRSA infection.

The developmental processes of ventricular septal defects with outflow tract malalignment.

Ventricular septal defects (VSD) with outflow tract (OFT) malalignment are a common group of congenital heart diseases with varying severity. The developmental process of these defects is challenging to understand due to the complex nature of cardiac morphogenesis and the difficulties in visualizing the temporal and spatial changes that occur during pathogenesis. However, recent advancements in imaging techniques, such as high-resolution episcopic microscopy, have provided valuable insights into the normal septation of ventricular chambers and OFT alignment. Building upon this knowledge, we have utilized lightsheet microscopy, another innovative imaging method, to further investigate the developmental processes that lead to abnormal formation of the ventricular septum and the malalignment of arterial roots with the ventricular chambers. Our study highlights endocardial cushion hypoplasia and insufficient rotation of the outflow tract as two interrelated central factors contributing to the pathogenesis of these defects. This finding has the potential to enhance our understanding of the etiology of congenital heart diseases and may contribute to the development of improved diagnostic and therapeutic strategies in the future.

Anshen Shumai Decoction inhibits post-infarction inflammation and myocardial remodeling through suppression of the p38 MAPK/c-FOS/EGR1 pathway.

Anshen Shumai Decoction (ASSMD) is traditionally employed to manage coronary artery disease arrhythmias. Its protective efficacy against myocardial infarction remains to be elucidated. This investigation employed a rat model of myocardial infarction, achieved through the ligation of the left anterior descending (LAD) coronary artery, followed by a 28-day administration of ASSMD. The study observed the decoction's mitigative impact on myocardial injury, with gene regulation effects discerned through transcriptomic analysis. Furthermore, ASSMD's influence on cardiomyocyte apoptosis and fibrotic protein secretion was assessed using an embryonic rat cardiomyocyte cell line (H9c2) under hypoxic conditions and rat cardiac fibroblasts subjected to normoxic culture conditions with TGF-ß. A functional rescue assay involving overexpression of FOS and Early Growth Response Factor 1 (EGR1), combined with inhibition of the p38 Mitogen-activated Protein Kinase (MAPK) pathway, was conducted. Results indicated that ASSMD significantly curtailed cardiomyocyte apoptosis and myocardial fibrosis in infarcted rats, primarily by downregulating FOS and EGR1 gene expression and inhibiting the upstream p38 MAPK pathway. These actions of ASSMD culminated in reduced expression of pro-apoptotic, collagen, and fibrosis-associated proteins, conferring myocardial protection and anti-fibrotic effects on cardiac fibroblasts.

Quantitative phosphoproteomics reveals molecular pathway network in wheat resistance to stripe rust.

Protein phosphorylation plays an important role in immune signaling transduction in plant resistance to pathogens. Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), severely devastates wheat production. Nonetheless, the molecular mechanism of wheat resistance to stripe rust remains limited. In this study, quantitative phosphoproteomics was employed to investigate the protein phosphorylation changes in wheat challenged by Pst. A total of 1537 and 2470 differentially accumulated phosphoproteins (DAPs) were identified from four early infection stage (6, 12, 18 and 24 h post-inoculation) in incompatible and compatible wheat-Pst interactions respectively. KEGG analysis revealed that Oxidative Phosphorylation, Phosphatidylinositol Signaling, and MAPK signaling processes are distinctively enriched in incompatible interaction, while Biosynthesis of secondary metabolites and RNA degradation process were significantly enriched in compatible interactions. In particular, abundant changes in phosphorylation levels of chloroplast proteins were identified, suggesting the regulatory role of photosynthesis in wheat-Pst interaction, which is further emphasized by protein-protein interaction (PPI) network analysis. Motif-x analysis identified [xxxxSPxxxx] motif, likely phosphorylation sites for defensive response-related kinases, and a new [xxxxSSxxxx] motif significantly enriched in incompatible interaction. The results shed light on the early phosphorylation events contributing to wheat resistance against Pst. Moreover, our study demonstrated that the phosphorylation levels of Nucleoside diphosphate kinase TaNAPK1 are upregulated at 12 hpi with CYR23 and at 24 hpi with CYR31. Transient silencing of TaNAPK1 was able to attenuate wheat resistance to CYR23 and CYR31. Our study provides new insights into the mechanisms underlying Pst-wheat interactions and may provide database to find potential targets for the development of new resistant varieties.

Cucurbit[8]uril-based supramolecular theranostics.

Different from most of the conventional platforms with dissatisfactory theranostic capabilities, supramolecular nanotheranostic systems have unparalleled advantages via the artful combination of supramolecular chemistry and nanotechnology. Benefiting from the tunable stimuli-responsiveness and compatible hierarchical organization, host-guest interactions have developed into the most popular mainstay for constructing supramolecular nanoplatforms. Characterized by the strong and diverse complexation property, cucurbit[8]uril (CB[8]) shows great potential as important building blocks for supramolecular theranostic systems. In this review, we summarize the recent progress of CB[8]-based supramolecular theranostics regarding the design, manufacture and theranostic mechanism. Meanwhile, the current limitations and corresponding reasonable solutions as well as the potential future development are also discussed.

Floating MIL-88A(Fe)@expanded perlites catalyst for continuous photo-Fenton degradation toward tetracyclines under artificial light and real solar light.

In this work, MIL-88A(Fe) was immobilized onto the expanded perlites to fabricate the floating MIL-88A(Fe)@expanded perlites (M@EP) catalyst via high throughput batch synthesis method under room temperature. The as-prepared M@EP could efficiently activate H2O2 to achieve 100% tetracycline antibiotics (TCs) removal under both artificial low power UV light (UVL) and real sunlight (SL) irradiation. The toxicological evaluation, growth experiment of mung beans and antimicrobial estimation revealed the decreasing aquatic toxicity of the TCs intermediates compared to those of the pristine TCs. A self-designed continuous bed reactor was employed to investigate the long-term operation of the M@EP. The findings demonstrated that the antibiotics mixture can be continuously degraded up to 7 days under UVL and 5 daytimes under SL irradiation, respectively. More importantly, ca. 76.9% and 81.6% of total organic carbon (TOC) removal efficiencies were accomplished in continuous bed reactor under UVL and SL irradiation, respectively. This work advances the immobilized MOFs on floating supports for their practical application in large-scale wastewater purification through advanced oxidation processes. ENVIRONMENTAL IMPLICATION: This work presented the high throughput production and photo-Fenton degradation application of floating MIL-88A(Fe)@expanded perlites (M@EP). Three tetracycline antibiotics (TCs) were selected as model pollutants to test the degradation ability of M@EP in batch experiment and continuous operation under artificial light and solar light. The complete TCs degradation could be accomplished in self-designed device up to 7 d under UV light and 5 d under real solar light. This work tapped a new door to push MOFs-based functional materials in the real water purification.

Nucleus-targeted carbon dots as peroxidase nanozyme for photoacoustic imaging and phototherapy of tumor.

High-purity carbon dots (CDs) with a highly π-conjugated sp2-hybridized graphite structure were prepared by the pulse electrolysis method using the graphite plate as raw material. Photoacoustic signal together with photothermal effect was found in the CDs-dispersed suspensions under near-infrared (NIR) irradiation. For the suspension with the CDs concentration of 500 µg/mL, the photothermal conversion efficiency is high up 64.3% and the solution's temperature can be increased to 82.2 °C under NIR irradiation. Moreover, CDs can be effectively endocytosed by human hepatoma (HepG2) cells with a few hours, act as peroxidase nanozyme to decompose H2O2 and facilitate the production of reactive oxygen species. Under NIR irradiation, CDs exhibit an outstanding apoptosis-inducing effect on HepG2 cells by the photothermal effect. In addition, in vivo experiments show that CDs can be used in photoacoustic imaging (PAI) and guiding the tumor treatment. As a result, the nucleus-targeted CDs with an unique combination of PAI and photothermal effect have potential in cancer diagnosis and treatment.

Unravelling the mechanism of columnar-to-equiaxed transition and grain refinement in ultrasonic vibration assisted laser welding of Ti6Al4V titanium alloy.

In this study, the microstructural evolution and mechanical properties of Ti6Al4V titanium alloy welded joints subjected to ultrasonic assisted laser welding were scrutinized, while numerical simulations were employed to explicate the grain refinement mechanism. The simulations indicate that the ultrasonic vibration significantly improves the overall fluidity and temperature of the molten pool. Under the identical condition of laser power and welding speed (1500 W, 1.3 m/min), the presence of 0.2A ultrasonic current yields a more uniform refinement of columnar grains, along with a denser arrangement of acicular martensite. The refinement mechanism can be attributed to the small temperature gradient, cavitation effects, and stress induced by ultrasonic vibration. Notably, the welded joint attains a peak tensile strength of 945.2 MPa under the aforementioned 0.2A condition, distinctly demonstrating the characteristics of ductile fracture. This research further reveals the underlying mechanism of grain refinement in Ti6Al4V alloy laser-welded joints induced by ultrasonic vibration, providing valuable references for optimizing process parameters and improving the quality of such welded joints.

Enhancing the effectiveness of Polymyxin E with a Fisetin Nanoemulsion against a Colistin-resistant Salmonella typhimurium infection.

BACKGROUND: Polymyxin E is widely recognized as a last resort for treating multidrug-resistant gram-negative bacteria. Unfortunately, the effectiveness of polymyxin E is significantly reduced when treating life-threatening bacterial infections due to plasmid-mediated polymyxin E resistance. The synergistic effect of applying a polymyxin E adjuvant is a promising strategy for overcoming the growing threat of antibiotic-resistant pathogens. PURPOSE: To evaluate the synergistic effect of fisetin and polymyxin E on S. typhimurium infections in vivo and further elucidate the underlying mechanism of this effect. METHODS: The effect of combining fisetin and polymyxin E to treat mobilized colistin resistance-1-positive (MCR-1-positive) gram-negative bacteria in vitro was examined using various methods, such as checkerboard assays, growth curves and time‒kill curves. To elucidate the mechanism by which fisetin affects MCR-1, we employed ultraviolet (UV) absorption spectroscopy, thin layer chromatography (TLC), and western blot analysis to investigate its effect at the protein level. Subsequently, molecular dynamics simulations (MDS) and metabolomics analysis were utilized to determine the site of interaction between fisetin and MCR-1 as well as the potential pathways and mechanisms involved. A new nanoemulsion of fisetin was produced using high-pressure homogenization, and its stability was tested. Finally, two animal models of S. typhimurium HYM2 infection were established to evaluate the synergistic effect of polymyxin E and fisetin in vivo. RESULTS: Our study revealed that fisetin exhibited a synergistic effect when combined with polymyxin E against MCR-1-positive S. typhimurium. The TLC results demonstrated that fisetin could inhibit the phosphoethanolamine (PEA) transfer of the MCR-1 protein, thereby restoring the activity of polymyxin E in strains against MCR-1. The MDS analysis indicated robust and immediate binding between fisetin and the MCR-1 protein, with both hydrophobic and polar effects playing significant roles in determining the binding energy of the former. Metabolomic studies demonstrated that the addition of fisetin significantly modulated bacterial metabolites. Moreover, it effectively inhibited the activity of ABC transporters in bacteria, thereby mitigating bacterial drug resistance and enhancing the therapeutic efficacy of polymyxin E. Furthermore, in mouse and chick models of infection, intragastric administration of the fisetin nanoemulsion together with polymyxin E resulted in significant therapeutic benefits, including increased survival rates, reduced bacterial colonization, and decreased levels of inflammatory factors. CONCLUSION: Fisetin, an MCR-1 inhibitor and a promising synergistic partner of polymyxin E, has significant potential for clinical application in the treatment of S. typhimurium infections, particularly those resulting extensively from drug-resistant MCR-1-positive strains.

Repurposing harmaline as a novel approach to reverse tmexCD1-toprJ1-mediated tigecycline resistance against klebsiella pneumoniae infections.

BACKGROUND: A novel plasmid-mediated resistance-nodulation-division (RND) efflux pump gene cluster tmexCD1-toprJ1 in Klebsiella pneumoniae tremendously threatens the use of convenient therapeutic options in the post-antibiotic era, including the "last-resort" antibiotic tigecycline. RESULTS: In this work, the natural alkaloid harmaline was found to potentiate tigecycline efficacy (4- to 32-fold) against tmexCD1-toprJ1-positive K. pneumoniae, which also thwarted the evolution of tigecycline resistance. Galleria mellonella and mouse infection models in vivo further revealed that harmaline is a promising candidate to reverse tigecycline resistance. Inspiringly, harmaline works synergistically with tigecycline by undermining tmexCD1-toprJ1-mediated multidrug resistance efflux pump function via interactions with TMexCD1-TOprJ1 active residues and dissipation of the proton motive force (PMF), and triggers a vicious cycle of disrupting cell membrane integrity and metabolic homeostasis imbalance. CONCLUSION: These results reveal the potential of harmaline as a novel tigecycline adjuvant to combat hypervirulent K. pneumoniae infections.