Keyu Zhang

Acanthopanax gracilistylus W. W. Smith is a traditional Chinese herbal medicine that contains a variety of bioactive components, including polysaccharides. In this study, a polysaccharide was extracted from A. gracilistylus (AGSP) using an aqueous alcohol precipitation method. The sugar and glucuronic acid contents of AGSP are 43% and 8.06%, respectively. It was consisted of seven monosaccharides, mannose (Man), rhamnose (Rha), glucuronic acid (GlcA), galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara), with molar ratios of 0.32:0.15:0.04:0.12:5.12:2.50:0.85. AGSP liposomes (AGSPL) was prepared via the reverse-phase evaporation method. The encapsulation rate of AGSPL was 45.17% and its average particle size, polymer dispersity index (PDI), and zeta potential were 98.79 nm, 0.191, and −8.38 mV, respectively. The proliferation of chicken splenic T and B lymphocytes was significantly promoted in vitro at AGSP concentrations of 125–250 μg/mL and AGSPL concentrations of 15.63–31.25 μg/mL and 1.95–15.63 μg/mL, respectively. In vivo, the HI antibody titers and the concentrations of IFN-γ, IL-2, IL-4, and IL-6 in the AGSP and AGSPL groups were higher than those in the vaccine control (VC) and blank control (BC) groups. The efficacy of AGSPL was superior to that of AGSP. These findings indicate that AGSP and AGSPL markedly enhance the immunogenicity of ND vaccines, especially AGSPL, which is a promising candidate for polysaccharide-based vaccine diluents or adjuvants.

Methicillin-resistant Staphylococcus aureus (MRSA) remains a leading cause of hospital-acquired infections, often linked to complicated treatments, increased mortality risk, and significant cost burdens. Several antibacterial agents have been developed to address MRSA resistance. In this study, potential agents to combat MRSA resistance were explored, with the antibacterial activity of synthesized α-mangostin (α-MG) derivatives being evaluated alongside investigations into their cellular mechanisms against MRSA2. α-MG-4, featuring an allyl group at C3 of the lead compound α-MG, restored the sensitivity of MRSA2 to penicillin, enrofloxacin, and gentamicin, while also demonstrating improved safety profiles. Although α-MG-4 alone was ineffective against MRSA2, it exhibited an optimal synergistic ratio in vitro when combined with these antibiotics. This significant synergistic antibacterial effect was further confirmed in vivo using a mouse skin abscess model. Additionally, the synergistic mechanisms revealed that α-MG-4 was associated with changes in membrane permeability and inhibition of the MepA and NorA genes, which encode the efflux pumps of MRSA2. α-MG-4 also inhibited PBP2a expression, potentially by occupying a crucial binding site in a dose-dependent manner. IMPORTANCE: Methicillin-resistant Staphylococcus aureus (MRSA)’s resistance to multiple antibiotics poses significant health and safety concerns. A novel α-mangostin (α-MG) derivative, α-MG-4, was first identified as a xanthone-based PBP2a inhibitor that reverses MRSA2 resistance to penicillin. The synergistic antibacterial effects of α-MG-4 were linked to increased cell membrane permeability and the inhibition of genes involved in efflux pump function.

The rapid expansion of antibiotic-resistant bacterial diseases is a global burden on public health. It makes sense to repurpose and reposition already-approved medications for use as supplementary agents in synergistic combinations with existing antibiotics. Here, we demonstrate that the anthelmintic drug nitazoxanide (NTZ) synergistically enhances the effectiveness of the lipopeptide antibiotic polymyxin B in inhibiting gram-negative bacteria, including those resistant to polymyxin B. Mechanistic investigations revealed that nitazoxanide inhibited calcium influx and cell membrane depolarization, enhanced the affinity between polymyxin B and the extracellular membrane, and promoted intracellular ATP depletion and an increase in reactive oxygen species (ROS), thus enhancing the penetration and disruption of the Escherichia coli cell membrane by polymyxin B. The transcriptomic analysis revealed that the combination resulted in energy depletion by inhibiting both aerobic and anaerobic respiration patterns in bacterial cells. The increased bactericidal effect of polymyxin B on the E. coli ∆nuoC strain further indicates that NuoC could be a promising target for nitazoxanide. Furthermore, the combination of nitazoxanide and polymyxin B showed promising therapeutic effects in a mouse infection model infected with E. coli . Taken together, these results demonstrate the potential of nitazoxanide as a novel adjuvant to polymyxin B, to overcome antibiotic resistance and improve therapeutic outcomes in refractory infections. IMPORTANCE: The rapid spread of antibiotic-resistant bacteria poses a serious threat to public health. The search for potential compounds that can increase the antibacterial activity of existing antibiotics is a promising strategy for addressing this issue. Here, the synergistic activity of the FDA-approved agent nitazoxanide (NTZ) combined with polymyxin B was investigated in vitro using checkerboard assays and time-kill curves. The synergistic mechanisms of the combination of nitazoxanide and polymyxin B were explored by fluorescent dye, transmission electron microscopy (TEM), and transcriptomic analysis. The synergistic efficacy was evaluated in vivo by the Escherichia coli and mouse sepsis models. These results suggested that nitazoxanide, as a promising antibiotic adjuvant, can effectively enhance polymyxin B activity, providing a potential strategy for treating multidrug-resistant bacteria.

The prevalence of highly infectious influenza A virus (IAV) is still a major threat to global human health. Nitazoxanide (NTZ) possesses potent antiviral properties against the influenza virus. However, the role of small molecular metabolites and antioxidant stress in the NTZ’s anti-influenza virus mechanism is not yet fully understood. This study compared the changes in cellular metabolism, ROS levels, antioxidant enzyme activities, and Keap-1/Nrf2 pathway in IAV-infected MDCK cells after NTZ treatment in vitro, using LC-MS-based metabolomics, flow cytometry, immunoblot. We observed that the NTZ treatment in the IAV-infected cells drastically altered the metabolism of small molecules, among which eleven metabolites were highly relevant to NTZ. The virus induced oxidative stress was also remarkably suppressed by NTZ. Meanwhile, the Nrf2 pathway and some proteins with modulating antiviral activity were activated after NTZ treatment, protecting cells from IAV injury. Therefore, regulation of the intracellular oxidative state is the primary outcome of NTZ treatment, which may underpin an antiviral mechanism attributed to the thiazolide.

Background: Avian coccidiosis is an important parasitic disease that has serious adverse effects on the global poultry industry. The extensive use of anticoccidial drugs has resulted in an increase in drug resistance. Ethanamizuril (EZL) is a novel triazine with high anticoccidial activity. Methods: We compared oocyst production and sporulation between EZL-sensitive (S) and EZL-resistant Eimeria tenella strains (R10 and R200) and used label-free quantitative proteomics to identify differentially expressed proteins (DEPs) between these strains. Results: We generated two EZL-resistant E. tenella strains: strain R10, which was induced using a constant dose of 10 mg EZL/kg poultry feed, and strain R200, which was generated by gradually increasing the EZL dosage to 200 mg EZL/kg poultry feed. With an increase in resistance, the total oocyst output decreased, but the percentage of sporulation did not change significantly. We identified a total of 7511 peptides and 1282 proteins, and found 152 DEPs in the R10 strain versus the S strain, 426 DEPs in the R200 strain versus the S strain and 494 DEPs in the R200 strain versus the R10 strain. When compared with the S strain, 86 DEPs were found to have consistent trends in both resistant strains. The DEPs were primarily involved in ATP and GTP binding, invasion, and membrane components. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the DEPs suggested that they are involved in transcription and translation processes. Protein–protein interaction network analysis of the 86 DEPs showed that 10 proteins were hubs in the functional interaction network (≥ 8 edges) and five of them were ribosomal proteins. Conclusions: The results of the present study indicate that the resistance mechanisms of E. tenella against EZL might be related to the transcriptional and translational processes, especially in the factors that inhibit the growth of parasites. The DEPs found in this study provide new insights into the resistance mechanisms of E. tenella against EZL. Further research on these potential targets holds promise for new chemotherapeutic approaches for controlling E. tenella infections. Graphical