Galleria mellonella in vitro model for chromoblastomycosis shows large differences in virulence between isolates.

BACKGROUND: Chromoblastomycosis is the World Health Organization (WHO)-recognized fungal implantation disease that eventually leads to severe mutilation. Cladophialophora carrionii (C. carrionii) is one of the agents. However, the pathogenesis of C. carrionii is not fully investigated yet. METHODS: We investigated the pathogenic potential of the fungus in a Galleria mellonella (G. mellonella) larvae infection model. Six strains of C. carrionii, and three of its environmental relative C. yegresii were tested. The G. mellonella model was also applied to determine antifungal efficacy of amphotericin B, itraconazole, voriconazole, posaconazole, and terbinafine. RESULTS: All strains were able to infect the larvae, but virulence potentials were strain-specific and showed no correlation with clinical background of the respective isolate. Survival of larvae also varied with infection dose, and with growth speed and melanization of the fungus. Posaconazole and voriconazole exhibited best activity against Cladophialophora, followed by itraconazole and terbinafine, while limited efficacy was seen for amphotericin B. CONCLUSION: Infection behavior deviates significantly between strains. In vitro antifungal susceptibility of tested strains only partly explained the limited treatment efficacy in vivo.

Study on long-acting analgesic lappaconitine hydrobromide lyotropic liquid crystal injection / 药学学报

Long-acting analgesia is a common clinical treatment method after surgery. The slow-release injection with long-acting analgesia has the advantages of less medication frequency and stable effect. In this study, the analgesic drug lappaconitine hydrobromide lyotropic liquid crystal injection was prepared, and its sustained release mechanism, drug release and pharmacodynamic characteristics were evaluated. The results of polarizing microscope and freeze-transmission electron microscope showed that the lyotropic liquid crystal injection of the liquid crystal precursor preparation of lappaconitine hydrobromide could be obtained by the combination of glycerol monooleate (GMO) and soybean lecithin (SPC) in different proportions. The results of dissolution study in vitro showed that the drug release rate of different forms of liquid crystal preparations was layered liquid crystal > cubic liquid crystal > hexagonal liquid crystal. The mathematical model fitting results of the release data showed that the external release of layered liquid crystal, cubic liquid crystal and hexagonal liquid crystal conforms to the Ritger-Peppas model, and the release mechanism was Fick diffusion. The results of pharmacodynamics study in vivo showed that the analgesic effect of lappaconitine hydrobromide lyotropic liquid crystal injection lasted for 3 days, and there was no abnormality in the incision and local tissue, showing good safety and tolerance. The study on drug release and elimination process of the in vivo gel repository showed that lappaconitine hydrobromide could be completely released from the lyotropic liquid crystal 3 days after administration, and the sustained-release materials could be gradually eliminated locally. All animal experiments were approved by the Experimental Animal Ethics Committee of the Shanghai Institute of Materia Medica, Chinese Academy of Sciences (No. 2021-08-GY-61) and the experiments were conducted in accordance with the relevant guiding principles and regulations. The lyotropic liquid crystal injection of lappaconitine hydrobromide prepared in this study presented a solution state at room temperature, and underwent phase transition in contact with the body fluid at the administration site, formed a drug depot and exerted a slow drug release effect. This preparation can reduce systemic toxicity, prolong the duration of analgesia, reduce the number of administrations, improve the compliance of postoperative patients, and provide a reference for the design of long-term sustained release analgesic preparations.

Natural component plumbagin as a potential antibacterial agent against Streptococcus agalactiae infection.

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), can infect humans, terrestrial animals and fish. The emergence of bacterial resistance of S. agalactiae to antibiotics leads to an urgent need of exploration of new antimicrobial agents. In the study, the antibacterial activity of natural component plumbagin (PLB) against S. agalactiae was investigated in vitro and in vivo. The results showed that the minimal inhibitory concentration (MIC) of PLB against S. agalactiae was 8 mg/L. The growth curve assay revealed that PLB could inhibit the growth of S. agalactiae. In addition, the time-killing curve showed that S. agalactiae was killed almost completely by 2-fold MIC of PLB within 12 h. Transmission electron microscopy results showed obvious severe morphological destruction and abnormal cells of S. agalactiae after treated with PLB. The pathogenicity of S. agalactiae to zebrafish was significantly decreased after preincubation with PLB for 2 h in vitro, further indicating the bactericidal activity of PLB. Interestingly, PLB could kill S. agalactiae without inducing resistance development. Furthermore, pretreatment and post-treatment assays suggested that PLB also exhibited the antibacterial activity against S. agalactiae infection in vivo by effectively reducing the bacterial load and improving the survival rate of S. agalactiae-infected zebrafish. In summary, PLB had potent antibacterial activity against S. agalactiae in vitro and in vivo, and it could be an excellent antimicrobial candidate to prevent and control S. agalactiae infection.

Design and Pharmacodynamics of Recombinant Fungus Defensin NZL with Improved Activity against Staphylococcus hyicus In Vitro and In Vivo.

Staphylococcus hyicus is recognized as a leading pathogen of exudative epidermitis in modern swine industry. Antimicrobial peptides are attractive candidates for development as potential therapeutics to combat the serious threats of the resistance of S. hyicus. In this study, a series of derivatives were designed based on the NZ2114 template with the aim of obtaining peptides with more potent antimicrobial activity through changing net positive charge or hydrophobicity. Among them, a variant designated as NZL was highly expressed in Pichia pastoris (P. pastoris) with total secreted protein of 1505 mg/L in a 5-L fermenter and exhibited enhanced antimicrobial activity relative to parent peptide NZ2114. Additionally, NZL could kill over 99% of S. hyicus NCTC10350 in vitro within 8 h and in Hacat cells. The results of membrane permeabilization assay, morphological observations, peptide localization assay showed that NZL had potent activity against S. hyicus, which maybe kill S. hyicus through action on the cell wall. NZL also showed an effective therapy in a mouse peritonitis model caused by S. hyicus, superior to NZ2114 or ceftriaxone. Overall, these findings can contribute to explore a novel potential candidate against S. hyicus infections.

Design, synthesis and biological evaluation of novel 2,4-diaryl pyrimidine derivatives as selective EGFRL858R/T790M inhibitors.

Lung cancer is the leading cause of cancer deaths. It has been demonstrated that epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) are efficacious in patients with EGFR mutation-positive non-small cell lung cancer (NSCLC). In this work, a new series of 2,4-diaryl pyrimidine derivatives containing cyclopropyl moiety were designed, synthesized and evaluated as novel selective EGFRL858R/T790M inhibitors. The most promising compound, 8l demonstrated excellent kinase inhibitory activity against EGFR double mutation with IC50 value of 0.26 nM. Moreover, 8l provided strong activity against H1975 cells with IC50 value of 0.008 µM and exhibited little toxicity toward four non-tumorigenic cell lines. Furthermore, 8l showed potent anti-tumor efficacy in a murine EGFRL858R/T790M-driven H1975 xenograft model. These results indicated that 8l may be a promising drug candidate for further study.

A new high-yielding antimicrobial peptide NZX and its antibacterial activity against Staphylococcus hyicus in vitro/vivo.

Staphylococcus hyicus, considered as a leading pathogen of exudative epidermitis, is a serious threat to humans and animals. The emergency of bacterial resistance to antibiotics, especially in human and animal health fields, leads to an urgent need of exploration of new antimicrobial agents. In this study, NZX, a plectasin-derived peptide, was firstly expressed in Pichia pastoris X-33 and was purified by cation exchange chromatography, followed by detection of its antibacterial activity in vitro and in vivo. The results showed that the total secreted protein concentration in fermentation supernatant was up to 2820 mg/L (29 °C) after 120-h induction in a 5-L fermentor. The yield of NZX reached up to 965 mg/L with a purity of 92.6%. The recombinant expressed NZX had a strong antimicrobial activity, high stability, and low toxicity. The minimal inhibitory concentrations (MICs) of NZX and ceftriaxone (CRO) against Gram-positive bacteria were 0.46 to 0.91 µM and 6.04 to 12.09 µM, respectively. The time-killing curves showed that S. hyicus NCTC10350 was killed completely by 2× and 4 × MIC of NZX within 24 h. NZX also exhibited the intracellular activity against S. hyicus in Hacat cells. After treatment with NZX (10 mg/kg) and CRO (60 mg/kg), the survival rates of mice were 100% and 83.3%, respectively. NZX inhibited the bacterial translocation, downregulated pro-inflammatory cytokines (TNF-α/IL-1ß/IL-6), upregulated the anti-inflammatory cytokine (IL-10), and ameliorated multiple-organ injuries (the liver, spleen, lung, and kidney). This study provides evidence that the expressed NZX has the potential to become a powerful candidate as novel antimicrobial agents against S. hyicus infections.