Recent advances on the regulation of bacterial biofilm formation by herbal medicines.

Biofilm formation is a fundamental part of life cycles of bacteria which affects various aspects of bacterial-host interactions including the development of drug resistance and chronic infections. In clinical settings, biofilm-related infections are becoming increasingly difficult to treat due to tolerance to antibiotics. Bacterial biofilm formation is regulated by different external and internal factors, among which quorum sensing (QS) signals and nucleotide-based second messengers play important roles. In recent years, different kinds of anti-biofilm agents have been discovered, among which are the Chinese herbal medicines (CHMs). CHMs or traditional Chinese medicines have long been utilized to combat various diseases around the world and many of them have the ability to inhibit, impair or decrease bacterial biofilm formation either through regulation of bacterial QS system or nucleotide-based second messengers. In this review, we describe the research progresses of different chemical classes of CHMs on the regulation of bacterial biofilm formation. Though the molecular mechanisms on the regulation of bacterial biofilm formation by CHMs have not been fully understood and there are still a lot of work that need to be performed, these studies contribute to the development of effective biofilm inhibitors and will provide a novel treatment strategy to control biofilm-related infections.

A phage cocktail combined with the enteric probiotic Lactobacillus reuteri ameliorated mouse colitis caused by S. typhimurium.

Salmonella enterica serovar Typhimurium (S. typhimurium) is one of the most important foodborne pathogens that causes colitis in humans. In this study, we compared the effects of a therapeutic treatment using a phage cocktail (Pc) in combination or not with Lactobacillus reuteri (L. reuteri) in an S. typhimurium-induced colitis murine model. An oral administration of 4 × 108 CFU per mouse of S. typhimurium resulted in intestinal barrier disruption and severe inflammatory symptoms. S. typhimurium in the colon of the mice treated with the Pc and L. reuteri (PcLR) combination were completely removed compared to those in the single Pc or single L. reuteri treatment groups. Furthermore, compared with the infected group, the intestinal barrier and colonic pathological damage were significantly improved in the PcLR-treated group. Additionally, the short-chain fatty acid (SCFA) levels in the feces of the mice in the PcLR treatment group were significantly increased compared to those in the feces of the mice in the infected group. In addition, the combination of Pc with acetate and reuterin released by L. reuteri (PcReAc) can also achieve the same effect as PcLR treatment. Thus, these results indicated that the acetate and reuterin released by L. reuteri play an important role in the treatment. The extraordinary therapeutic effects of PcLR and PcReAc depend on the specific bactericidal activity of Pc and the broad-spectrum bactericidal activity and immunomodulation of L. reuteri (or acetate and reuterin) in the host. This study provides a new concept for the treatment of inflammatory diseases caused by intestinal pathogens.

Rapid and sensitive detection of Staphylococcus aureus using biolayer interferometry technology combined with phage lysin LysGH15.

Staphylococcus aureus (S. aureus), considered as a common foodborne pathogenic microorganism, usually causes food poisoning and various infectious diseases. Therefore, development of rapid and accurate bacterial detection method is the key to preventing food poisoning and achieving early diagnosis and treatment of various infectious diseases caused by S. aureus. Biolayer interferometry (BLI) technology is a novel technique of label-free optical analysis for real-time monitoring of biomolecular interactions. The C54A mutation induced the lytic activity loss of phage lysin LysGH15 but retained the capacity for specific recognizing and binding S. aureus. In this study, a novel method for the detection of S. aureus was established using the C54A mutant LysGH15 as the receptor in combination with BLI. Using this BLI-based method, S. aureus whole cells could be directly assayed and the limit of detection was 13 CFU/mL with a binding time of 12 min. Because the C54A mutant LysGH15 recognizes S. aureus with very high specificity, the method can exclude potential interference from other bacterial species. In addition, this method could also distinguish between viable and dead S. aureus. Moreover, S. aureus was successfully detected in ice cubes and light soy sauce by using this method. Collectively, these results indicate that the LysGH15-based BLI method can be used as an efficient and reliable diagnostic tool in the field of food safety and other related fields for the rapid, sensitive, label-free, and real-time detection of S. aureus.

Development of paclitaxel loaded pegylated gelatin targeted nanoparticles for improved treatment efficacy in non-small cell lung cancer (NSCLC): an in vitro and in vivo evaluation study.

PURPOSE: To develop and evaluate paclitaxel (PTX) loaded pegylated gelatin targeted nanoparticles for improved efficacy in non-small cell lung cancer (NSCLC) treatment. METHOD: PTX loaded gelatin nanoparticles (PTX-GNP) were prepared by crosslinking with glutaraldehyde aqueous solution. These nanoparticles (NPs) were further incubated with PEG 400 to form PEGylated NPs (PEG-PTX-GNP). The NPs were evaluated for surface morphology, size, zeta potential, encapsulation efficiency, drug loading, in vitro drug release, cytotoxicity in an assay on cancer cell lines L132, in vitro cellular uptake in an assay in L132 and 293T cell lines, in vivo antitumor activity on female Balb/c mice, pulmonary deposition, histopathology, and immunohistochemical properties. RESULTS: The nanoparticles were of spherical shape with smooth surface characteristics. The observed DL was of 20.18 to 32.11%, as particle size was of 90 to 115 nm. Zeta potential and polydispersity index (PDI) were within acceptable ranges. Encapsulation was effective when the NPs had a size of 80.50 nm to 98.12 nm. The PEGylated PTX loaded nanoparticles (PEG-PTX-GNP, GNP4) showed similar PTX release profile to that of the NP4 formulation. PEGylated NPs showed the desired PTX release pattern that is required for cancer treatment. In an in vitro cytotoxicity study, PEG-PTX-GNP showed the maximum antiproliferative activity over the period of 24 hours, followed by PTX-GNP, pure PTX and BPEG-GNP. PEG-PTX-GNP showed the highest internalization within both cell lines, followed by PTX-GNP and pure PTX. The survival rate of animals in PEG-PTX-GNP group was 100%, proving the safety and efficacy of the treatment. PEG-PTX-GNP showed the highest antitumor activity as compared to other formulations. The pulmonary deposition rate was the highest (6.5 to 12.55 µg/g) in PEG-PTX-GNP formulations. Histopathology and immunohistochemical study proved that PEG-PTX-GNP had greater anticancer potential than other tested formulations. CONCLUSION: This study confirms the potential use of paclitaxel loaded PEGylated gelatin targeted nanoparticles for improved efficacy in non-small cell lung cancer (NSCLC) treatment.

HLA-DR expression on regulatory T cells is closely associated with the global immune activation in HIV-1 infected subjects naïve to antiretroviral therapy.

BACKGROUND: The frequencies of regulatory T cells (Tregs) increased over the HIV infection but its counts actually decreased. We proposed that the decrease of Treg counts may cause the reduction of inhibitory effect and thereby account for the over-activation of Tregs during HIV infection. However, it remains unknown whether Tregs are also over-activated and thereafter the activation induced death may lead to the decrease of Tregs. METHODS: Tregs were defined as CD4(+)CD25(+)CD127(lo/-) T cells. Eighty-one HIV-1 infected patients were enrolled in our study, and twenty-two HIV-1 seronegative donors were recruited as the control. The levels of HLA-DR on Tregs were determined by FACSAria flow cytometer. RESULTS: Compared to HIV-1 seronegative donors, the levels of HLA-DR on CD4(+)CD25(+)CD127(lo/-) Tregs were significantly increased in HIV-1 infected patients, and its increase was positively associated with viral loads (r = 0.3163, P = 0.004) and negatively with CD4 T-cell counts (r = -0.4153, P < 0.0001). In addition, significant associations between HLA-DR expression on CD4(+)CD25(+)CD127(lo/-) Tregs and the percentages of HLA-DR, CD38, Ki67 expressing CD4(+) and CD8(+) T cells were also identified. CONCLUSION: HLA-DR on Tregs is a good marker for viral replication and disease progression. The over-activation of Tregs might result in the decrease of Tregs.