CRISPR-AMRtracker: A novel toolkit to monitor the antimicrobial resistance gene transfer in fecal microbiota.

The spread of antibiotic resistance genes (ARGs), particularly those carried on plasmids, poses a major risk to global health. However, the extent and frequency of ARGs transfer in microbial communities among human, animal, and environmental sectors is not well understood due to a lack of effective tracking tools. We have developed a novel fluorescent tracing tool, CRISPR-AMRtracker, to study ARG transfer. It combines CRISPR/Cas9 fluorescence tagging, fluorescence-activated cell sorting, 16S rRNA gene sequencing, and microbial community analysis. CRISPR-AMRtracker integrates a fluorescent tag immediately downstream of ARGs, enabling the tracking of ARG transfer without compromising the host cell's antibiotic susceptibility, fitness, conjugation, and transposition. Notably, our experiments demonstrate that sfGFP-tagged plasmid-borne mcr-1 can transfer across diverse bacterial species within fecal samples. This innovative approach holds the potential to illuminate the dynamics of ARG dissemination and provide valuable insights to shape effective strategies in mitigating the escalating threat of antibiotic resistance.

Targeted inhibition of gut bacterial ß-glucuronidases by octyl gallate alleviates mycophenolate mofetil-induced gastrointestinal toxicity.

Mycophenolate mofetil (MMF) is a viable therapeutic option against various immune disorders as a chemotherapeutic agent. Nevertheless, its application has been undermined by the gastrotoxic metabolites (mycophenolic acid glucuronide, MPAG) produced by microbiome-associated ß-glucuronidase (ßGUS). Therefore, controlling microbiota-produced ßGUS underlines the potential strategy to improve MMF efficacy by overcoming the dosage limitation. In this study, the octyl gallate (OG) was identified with promising inhibitory activity on hydrolysis of PNPG in our high throughput screening based on a chemical collection of approximately 2000 natural products. Furthermore, OG was also found to inhibit a broad spectrum of BGUSs, including mini-Loop1, Loop 2, mini-Loop 2, and mini-Loop1,2. The further in vivo experiments demonstrated that administration of 20 mg/kg OG resulted in predominant reduction in the activity of BGUSs while displayed no impact on the overall fecal microbiome in mice. Furthermore, in the MMF-induced colitis model, the administration of OG at a dosage of 20 mg/kg effectively mitigated the gastrointestinal toxicity, and systematically reverted the colitis phenotypes. These findings indicate that the OG holds promising clinical potential for the prevention of MMF-induced gastrointestinal toxicity by inhibition of BGUSs and could be developed as a combinatorial therapy with MFF for better clinical outcomes.

Innovative Delivery System Combining CRISPR-Cas12f for Combatting Antimicrobial Resistance in Gram-Negative Bacteria.

Antimicrobial resistance poses a significant global challenge, demanding innovative approaches, such as the CRISPR-Cas-mediated resistance plasmid or gene-curing system, to effectively combat this urgent crisis. To enable successful curing of antimicrobial genes or plasmids through CRISPR-Cas technology, the development of an efficient broad-host-range delivery system is paramount. In this study, we have successfully designed and constructed a novel functional gene delivery plasmid, pQ-mini, utilizing the backbone of a broad-host-range Inc.Q plasmid. Moreover, we have integrated the CRISPR-Cas12f system into the pQ-mini plasmid to enable gene-curing in broad-host of bacteria. Our findings demonstrate that pQ-mini facilitates the highly efficient transfer of genetic elements to diverse bacteria, particularly in various species in the order of Enterobacterales, exhibiting a broader host range and superior conjugation efficiency compared to the commonly used pMB1-like plasmid. Notably, pQ-mini effectively delivers the CRISPR-Cas12f system to antimicrobial-resistant strains, resulting in remarkable curing efficiencies for plasmid-borne mcr-1 or blaKPC genes that are comparable to those achieved by the previously reported pCasCure system. In conclusion, our study successfully establishes and optimizes pQ-mini as a broad-host-range functional gene delivery vector. Furthermore, in combination with the CRISPR-Cas system, pQ-mini demonstrates its potential for broad-host delivery, highlighting its promising role as a novel antimicrobial tool against the growing threat of antimicrobial resistance.

Mechanisms of gastrointestinal toxicity in neuromyelitis optica spectrum disorder patients treated with mycophenolate mofetil: insights from a mouse model and human study.

Mycophenolate mofetil (MMF) is commonly utilized for the treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a subset of patients experience significant gastrointestinal (GI) adverse effects following MMF administration. The present study aims to elucidate the underlying mechanisms of MMF-induced GI toxicity in NMOSD. Utilizing a vancomycin-treated mouse model, we compiled a comprehensive data set to investigate the microbiome and metabolome in the GI tract to elucidate the mechanisms of MMF GI toxicity. Furthermore, we enrolled 17 female NMOSD patients receiving MMF, who were stratified into non-diarrhea NMOSD and diarrhea NMOSD (DNM) groups, in addition to 12 healthy controls. The gut microbiota of stool samples was analyzed using 16S rRNA gene sequencing. Vancomycin administration prevented weight loss and tissue injury caused by MMF, affecting colon metabolomes and microbiomes. Bacterial ß-glucuronidase from Bacteroidetes and Firmicutes was linked to intestinal tissue damage. The DNM group showed higher alpha diversity and increased levels of Firmicutes and Proteobacteria. The ß-glucuronidase produced by Firmicutes may be important in causing gastrointestinal side effects from MMF in NMOSD treatment, providing useful information for future research on MMF. IMPORTANCE: Neuromyelitis optica spectrum disorder (NMOSD) patients frequently endure severe consequences like paralysis and blindness. Mycophenolate mofetil (MMF) effectively addresses these issues, but its usage is hindered by gastrointestinal (GI) complications. Through uncovering the intricate interplay among MMF, gut microbiota, and metabolic pathways, this study identifies specific gut bacteria responsible for metabolizing MMF into a potentially harmful form, thus contributing to GI side effects. These findings not only deepen our comprehension of MMF toxicity but also propose potential strategies, such as inhibiting these bacteria, to mitigate these adverse effects. This insight holds broader implications for minimizing complications in NMOSD patients undergoing MMF therapy.

Waterborne polyurethane nanoparticles incorporating linoleic acid as a potential strategy for controlling antibiotic resistance spread in the mammalian intestine.

Plasmid-mediated conjugative transfer of antibiotic resistance genes (ARGs) within the human and animal intestine represents a substantial global health concern. linoleic acid (LA) has shown promise in inhibiting conjugation in vitro, but its in vivo effectiveness in the mammalian intestinal tract is constrained by challenges in efficiently reaching the target site. Recent advancements have led to the development of waterborne polyurethane nanoparticles for improved drug delivery. In this study, we synthesized four waterborne polyurethane nanoparticles incorporating LA (WPU@LA) using primary raw materials, including N-methyldiethanolamine, 2,2'-(piperazine-1,4-diyl) diethanol, isophorone diisocyanate, castor oil, and acetic acid. These nanoparticles, identified as WPU0.89@LA, WPU0.99@LA, WPU1.09@LA, and WPU1.19@LA, underwent assessment for their pH-responsive release property and biocompatibility. Among these, WPU0.99@LA displayed superior pH-responsive release properties and biocompatibility towards Caco-2 and IPEC-J2 cells. In a mouse model, a dosage of 10 mg/kg/day WPU0.99@LA effectively reduced the conjugation of IncX4 plasmids carrying the mobile colistin resistance gene (mcr-1) by more than 45.1-fold. In vivo toxicity assessment demonstrated that 10 mg/kg/day WPU0.99@LA maintains desirable biosafety and effectively preserves gut microbiota homeostasis. In conclusion, our study provides crucial proof-of-concept support, demonstrating that WPU0.99@LA holds significant potential in controlling the spread of antibiotic resistance within the mammalian intestine.

Resistance monitoring and mechanism in the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) for chlorantraniliprole from Sichuan Province, China.

The fall armyworm, Spodoptera frugiperda (Noctuidae: Lepidoptera), is a wide-reaching notorious insect pest of important cereal crops, which has developed resistance to multiple classes of insecticides. It invaded the Sichuan Province of China in 2019. In this study, we performed resistance monitoring of insecticides for 11 field-collected populations from Sichuan, and all the populations were susceptible to emamectin benzoate and chlorpyrifos. The variations in resistance level to indoxacarb (resistance ratio (RR), 9.23-45.53-fold), spinetoram (RR, 4.32-18.05-fold), and chlorantraniliprole (RR, 2.02-10.39-fold) were observed among these populations. To investigate the resistance mechanism of chlorantraniliprole, synergism tests were performed and showed that piperonyl butoxide had a slight synergistic effect on chlorantraniliprole for the QJ-20 population (1.43-fold) in moderate resistance (RR, 10.39-fold) compared with the treatment group without synergist. Furthermore, the expression scanning for resistance-related genes showed that five P450 genes (CYP6AE43, CYP321A8, CYP305A1, CYP49A1, and CYP306A1) and the ryanodine receptor gene (Ryr, chlorantraniliprole target) were overexpressed in the QJ-20 population. These results indicated that the fall armyworm in Sichuan has exhibited diverse susceptibilities to several classes of insecticides, and the overexpression of Ryr and several P450 genes may contribute to the development of resistance in S. frugiperda to chlorantraniliprole.

Recombinant human endostatin inhibits adjuvant arthritis by down-regulating VEGF expression and suppression of TNF-α, IL-1ß production.

OBJECTIVE: The aim of this study was to examine the effect of recombinant human endostatin (rhEndostatin) on adjuvant arthritis (AA) in rats and its possible mechanisms. METHODS: RhEndostatin was subcutaneously administrated to AA rats after immunization. The progression of AA was assessed by the macroscopic arthritis scoring system of paws. Histological examination of the synovial tissues was examined by hematoxylin and eosin staining. The expression level of vascular endothelial growth factor (VEGF) mRNA and proteins in the synovial tissues was evaluated by realtime PCR and immunohistochemistry, respectively. Fibroblast-like synoviocytes (FLS) were isolated from synovial tissues. Cell proliferation assay was evaluateded with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. The levels of tumour necrosis factor-alpha (TNF-α) and interleukin-1ß (IL-1ß) in culture medium was examined by radioimmno assay. RESULTS: RhEndostatin attenuated the severity of arthritis on both second hind paw volume and polyarthritis score, as well as improved the arthritic status histologically in AA rats. Simultaneously, rhEndostatin can inhibit the expression of VEGF in synovial tissues. The proliferation of FLS and TNF-α, IL-1ß production from culture medium was significantly inhibited by rhEndostatin. CONCLUSION: Our data suggest that rhEndostatin inhibits adjuvant arthritis by down-regulating VEGF expression and suppression of TNF-α, IL-1ß production.

Protective effects of total flavonoids of Bidens bipinnata L. against carbon tetrachloride-induced liver fibrosis in rats.

Bidens bipinnata L. is well known in China as a traditional Chinese medicine and has been used to treat hepatitis in clinics for many years. In a previous study we found that total flavonoids of Bidens bipinnata L. (TFB) had a protective effect against carbon tetrachloride (CCl4)-induced acute liver injury in mice. Now this study was designed to investigate its therapeutic effect against CCl4-induced liver fibrosis in rats and to determine, in part, its mechanism of action. The liver fibrosis model was established by subcutaneous injection of 50% CCl4 twice a week for 18 weeks. TFB (40, 80 and 160 mg kg(-1)) was administered by gastrogavage daily from the 9th week. The results showed that TFB (80 and 160 mg kg(-1)) treatment for 10 weeks significantly reduced the elevated liver index (liver weight/body weight) and spleen index (spleen weight/body weight), elevated levels of serum transaminases (alanine aminotransferase and aspartate aminotransferase), hyaluronic acid, type III procollagen and hepatic hydroxyproline. In addition, TFB markedly inhibited CCl4-induced lipid peroxidation and enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. Moreover, TFB (80 and 160 mg kg(-1)) treatment improved the morphologic changes of hepatic fibrosis induced by CCl4 and suppressed nuclear factor (NF)-kappaB, alpha-smooth muscle actin (SMA) protein expression and transforming growth factor (TGF)-beta1 gene expression in the liver of liver fibrosis of rats. In conclusion, TFB was able to ameliorate liver injury and protect rats from CCl4-induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF-kappaB on hepatic stellate cell activation and the expression of TGF-beta1.

Protective effects of total flavonoids of Bidens pilosa L. (TFB) on animal liver injury and liver fibrosis.

The hepatoprotective effects of total flavonoids of Bidens pilosa L. (TFB), a traditional Chinese medicine were evaluated in carbon tetrachloride (CCl(4))-induced liver injury in mice and rats. Total flavonoids of Bidens pilosa L. (25, 50 and 100mg/kg) were administered via gavage daily for 10 days to CCl(4)-treated mice as well as TFB (30, 60 and 90mg/kg) administered for 6 weeks to CCl(4)-treated rats. Liver index (liver weight/body weight), serum levels of transaminases (alanine aminotransferase, ALT and aspartate aminotransferase, AST), hepatic malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were evaluated following the 10 days treatment in mice. In addition histopathologic changes and nuclear factor-kappaB (NF-kappaB) expression of the liver were detected with hematoxylin-eosin (HE) and immunohistochemistry methods, respectively. The results showed that TFB (50 and 100mg/kg) effectively reduced the CCl(4)-induced elevated liver index, serum ALT, AST levels, hepatic MDA content, and restored hepatic SOD, GSH-Px activities in acute liver injury mice. TFB (60 and 90mg/kg) treatment significantly inhibited NF-kappaB activation in liver fibrosis of rats. The histopathological analysis suggested that TFB reduced the degree of liver injury in mice and severity of liver fibrosis in rats. These results suggested that TFB had a protective and therapeutic effect on animal liver injury, which might be associated with its antioxidant properties and inhibition of NF-kappaB activation.

One-month toxicokinetic study of SHENMAI injection in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: 'SHENMAI' injection (SMI) has been widely used in cardioprotection and modulation of the immune system because of its great efficacy. SMI primarily comprises the saponins from Panax ginseng and Ophiopogon japonicas. The profiles of saponins in SMI during long-term toxicokinetics remain unclear. MiR-146a possesses excellent sensitivity as a bio-marker in the innate immunity modification effect of SMI. AIM OF THE STUDY: Is to monitor the exposure level of SMI during a one-month toxicokinetic experiment, an analytical method involving ESI-LC-MS/MS technology was developed to determine 20 (S)-protopanaxadiol-type ginsenoside (Rb1, Rb2, Rc, Rd), 20 (S)-protopanaxatriol-type ginsenoside (Rg1, Re, Rf), oleanolic acid-type ginsenoside (Ro), and ophiopogonin D in rats. The levels of AST, CK, ALT, SOD, GSH-pX, MDA, miR-146a, and ECG were measured to explore the effects of SMI in cardiologic function and immune activity. RESULTS: Results show that the levels of AST, CK, and MDA decreased upon the administration of SMI. The level of miR-146a increased upon the administration of SMI dosage. During the administration of SMI, increasing exposure levels of 20 (S)-protopanaxadiol-type ginsenosides were also observed. CONCLUSION: The 20 (S)-protopanaxadiol-type ginsenosides were considered potential PK/TK markers because of their high exposure levels that continuously increased. Oxidative stress was slightly alleviated during the toxicokinetic study. Based on the level of miR-146a, negatively regulated innate immunity was observed. The regulation became more serious with increasing exposure levels of 20 (S)-protopanaxadiol-type ginsenosides. Negatively regulated innate immunity could be induced by long-term administration of SMI (>0.4g/kg).

Mechanism of fibroblast-like synoviocyte apoptosis induced by recombinant human endostatin in rats with adjuvant arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by pronounced synovial hyperplasia, in which there may be an imbalance between the growth and death of fibroblast-like synoviocytes (FLS). The present study was undertaken to examine the effect of recombinant human endostatin (rhEndostatin) on FLS apoptosis in experimental RA. Adjuvant arthritis (AA) was induced in male Sprague Dawley (SD) rats. Using cultured AA FLS obtained from these rats, the apoptosis process was measured by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) as well as Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling methods. In addition, the expression levels of the Fas, c-jun, NFkappaB, and caspase-3 gene products in synovial tissues were quantified by quantitative real-time polymerase chain reaction (qPCR) and/or Western blotting assays. Our data revealed that rhEndostatin induced apoptosis in AA FLS. The number and signal density of TUNEL-positive cells were significantly increased in rats treated with rhEndostatin (2.5 mg/kg). The percentage of Annexin V-FITC-positive cells was 6.67% after treatment with rhEndostatin at 25 microg/mL for 48 hr, compared with only 3.32% among untreated control cells. There were significant increases in Fas mRNA, c-jun mRNA, c-Jun protein, and caspase-3 (p20) protein in AA synovial tissues treated with rhEndostatin (2.5 mg/kg), whereas no significant difference in NFkappaB expression was detected between treated and untreated tissues. These findings indicate that rhEndostatin has a therapeutic effect on RA by inducing FLS apoptosis, which is strongly associated with increased expression of Fas, c-jun, and caspase-3, but not NFkappaB.