Quaternized antimicrobial peptide mimics based on harmane as potent anti-MRSA agents by multi-target mechanism covering cell wall, cell membrane and intracellular targets.

Infectious disease caused by methicillin-resistant Staphylococcus aureus (MRSA) seriously threatens public health. The design of antimicrobial peptide mimics (AMPMs) based on natural products (NPs) is a new strategy to kill MRSA and slow the development of drug resistance recently. Here, we reported the design and synthesis of novel AMPMs based on harmane skeleton. Notably, compound 9b exhibited comparable or even better anti-MRSA activity in vitro and in vivo with minimum inhibitory concentration (MIC) of 0.5-2 µg/mL than the positive drug vancomycin. The highly active compound 9b not only showed low cytotoxicity, no obvious hemolysis and good plasma stability, but also presented low tendency of developing resistance. Anti-MRSA mechanism revealed that compound 9b could destroy cell wall structure by interacting with lipoteichoic acid and peptidoglycan, cause membrane damage by depolarization, increased permeability and destructed integrity, reduce cell metabolic activity by binding to lactate dehydrogenase (LDH), interfere cellular redox homeostasis, and bind to DNA. Overall, compound 9b killed the MRSA by multi-target mechanism, which provide a promising light for combating the growing MRSA resistance.

Transfer and risk assessment of fipronil in laying hen tissues and eggs.

Fipronil is a persistent insecticide known to transfer into hen eggs from exposure from animal drinking water and feed, but some questions remain regarding its transfer behavior and distribution characteristics. Therefore, the dynamic metabolism, residue distribution and transfer factor (TF) of fipronil were investigated in 11 edible tissues of laying hens and eggs over 21 days. After a continuous low-dose drinking water exposure scenario, the sum of fipronil and all its metabolites (defined as fipronilT) quickly transferred to each edible tissue and gradually increased with exposure time. FipronilT residue in eggs first appeared at 3 days and then gradually increased. After a single high-dose feed exposure scenario, fipronilT residue in edible tissues first appeared after 2 h, quickly peaked at 1 day, and then gradually decreased. In eggs, fipronilT residue first appeared at 2 days, peaked 6-7 days and then gradually decreased. The TF values followed the order of the skin (0.30-0.73) > egg yolk (0.30-0.71) > bottom (0.21-0.59) after drinking water exposure, and the order of the skin (1.01-1.59) > bottom (0.75-1.1) > egg yolk (0.58-1.10) for feed exposure. Fipronil sulfone, a more toxic compound, was the predominant metabolite with higher levels distributed in the skin and bottom for both exposure pathways. FipronilT was distributed in egg yolks rather than in albumen owing to its lipophilicity, and the ratio of egg yolk to albumen may potentially reflect the time of exposure. The distinction is that the residues after feed exposure were much higher than that after drinking water exposure in edible tissues and eggs. The study highlights the residual characteristics of two exposure pathways, which would contribute to the tracing of contamination sources and risk assessment.

An inulin-based glycovesicle for pathogen-targeted drug delivery to ameliorate salmonellosis.

The gut microbiota plays a significant role in the pathogenesis and remission of inflammatory bowel disease. However, conventional antibiotic therapies may alter microbial ecology and lead to dysbiosis of the gut microbiome, which greatly limits therapeutic efficacy. To address this challenge, novel nanomicelles that couple inulin with levofloxacin via disulfide bonds for the treatment of salmonellosis were developed in this study. Owing to their H2S-responsiveness, the nanomicelles can target the inflamed colon and rapidly release levofloxacin to selectively fight against enteric pathogens. Moreover, the embedded inulin can serve as prebiotic fiber to increase the amount of Bifidobacteria and Lactobacilli in mice with salmonellosis, thus maintaining the intestinal mechanical barrier and regulating the balance of the intestinal flora. Therefore, multifunctional nanomicelles had a better curative effect than pure levofloxacin on ameliorating inflammation in vivo. The pathogen-targeted glycovesicle represents a promising drug delivery platform to maximize the efficacy of antibacterial drugs for the treatment of inflammatory bowel disease.

Synthesis of 3-formyl-eudistomin U with anti-proliferation, anti-migration and apoptosis-promoting activities on melanoma cells.

The discovery of new lead skeleton against melanoma are urgently needed due to its highly malignant and mortality. Herein, a new molecular entity (EU-5) derived from eudistomin U was synthesized with total yield of 46%, which displayed potent activity against malignant melanoma A375 cells (IC50 = 4.4 µM), no hemolytic toxicity and good physicochemical properties in silico. Colony formation and cell cycle arrest assays revealed that EU-5 suppressed cell proliferation by causing cell cycle arrest at G0/G1 phase. Wound healing and transwell assays suggested that EU-5 could effectively inhibit migration of A375 cells in a dose-dependent manner. Calcein-AM/PI staining, Annexin V-FITC/PI apoptosis detection, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), transcriptomics, quantitative real­time polymerase chain reaction (qRT­PCR), spectrometric titration and molecular docking assays indicated that EU-5 could activate p53 signaling pathway and trigger mitochondria-mediated cell apoptosis. Taken together, this study provided a promising lead structure for the design of a new generation of anti-melanoma drugs.

Analysis of Methylome, Transcriptome, and Lipid Metabolites to Understand the Molecular Abnormalities in Polycystic Ovary Syndrome.

Purpose: This study aimed to identify differentially methylated genes (DMGs) and differentially expressed genes (DEGs) to investigate new biomarkers for the diagnosis and treatment of polycystic ovary syndrome (PCOS). Methods: To explore the potential biomarkers of PCOS diagnosis and treatment, we performed methyl-binding domain sequencing (MBD-seq) and RNA sequencing (RNA-seq) on ovarian granulosa cells (GCs) from PCOS patients and healthy controls. MBD-seq was also performed on the ovarian tissue of constructed prenatally androgenized (PNA) mice. Differential methylation and expression analysis were implemented to identify DMGs and DEGs, respectively. The identified gene was further verified by real-time quantitative PCR (RT-qPCR) and methylation-specific PCR (MSP) in clinical samples. Furthermore, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was carried out on PCOS patients and healthy controls to identify differential lipid metabolites. Results: Compared to the control group, 13,526 DMGs related to the promoter region and 2429 DEGs were found. The function analysis of DMGs and DEGs showed that they were mainly enriched in glycerophospholipid, ovarian steroidogenesis, and other lipid metabolic pathways. Moreover, 5753 genes in DMGs related to the promoter region were screened in the constructed PNA mice. Integrating the DMGs data from PCOS patients and PNA mice, we identified the following 8 genes: CDC42EP4, ERMN, EZR, PIK3R1, ARHGEF18, NECTIN2, TSC2, and TACSTD2. RT-qPCR and MSP verification results showed that the methylation and expression of TACSTD2 were consistent with sequencing data. Additionally, 15 differential lipid metabolites were shown in the serum of PCOS patients. The differential lipids were involved in glycerophospholipid and glycerolipid metabolism. Conclusion: Using integration of methylome and lipid metabolites profiling we identified 8 potential epigenetic markers and 15 potential lipid metabolite markers for PCOS. Our results suggest that aberrant DNA methylation and lipid metabolite disorders may provide novel insights into the diagnosis and etiology of PCOS.

Substance P&dimethyloxallyl glycine-loaded carboxymethyl chitosan/gelatin hydrogel for wound healing.

Recent efforts have focused on preparing drug-loaded hydrogel for wound healing. In order to obtain an ideal hydrogel dressing for skin wound repair, a carboxymethyl chitosan-gelatin hydrogel was prepared for co-delivery of SP (substance P) and DMOG (dimethyloxallyl glycine) by a chemical cross-linking method using genipin as the cross-linking agent. The synthesized hydrogels have good biocompatibility and physicochemical properties due to the low toxicity of the hydrogel material. The three-dimensional network structure of the hydrogels supports cell migration and proliferation, and the combination of SP and DMOG drugs exhibited strong effects on cell proliferation. Moreover, the co-loaded drug hydrogels could significantly promote wound healing in vivo, and provide a potential hydrogel for wound healing.

Hydrogen sulfide-sensitive Chitosan-SS-Levofloxacin micelles with a high drug content: Facile synthesis and targeted Salmonella infection therapy.

The delivery system of antibiotics plays an important role in increasing the drug efficacy and reducing the risks of off-target toxicities and antibiotic resistance. The pathophysiology of bacterial infections is similar to that of tumor tissues, but only a few delivery systems have been able to target and release antibiotics on demand. Herein, we designed and developed a robust Chitosan-SS-Levofloxacin (CS-SS-LF) micelles for targeted antibiotic delivery, in which disulfide bond can be reduced by hydrogen sulfide (H2S), a typical product of Salmonella, and subsequently released antibiotic to eradicate Salmonella infection. CS-SS-LF micelles showed uniform size and sharp response to H2S. Compared with levofloxacin alone, these micelles possessed a better capacity in disrupting Salmonella biofilms and reducing bacterial burden in organs. The H2S-sensitive CS-SS-LF micelles might enable a new way to address bacterial infections.

Encapsulation of Lactobacillus rhamnosus in Hyaluronic Acid-Based Hydrogel for Pathogen-Targeted Delivery to Ameliorate Enteritis.

Probiotics were found to be effective in ameliorating the microbial dysbiosis and inflammation caused by intestinal pathogens. However, biological challenges encountered during oral delivery have greatly limited their potential health benefits. Here, a model probiotic (Lactobacillus rhamnosus) was encapsulated in an intestinal-targeted hydrogel to alleviate bacterial enteritis in a novel mode. The hydrogel was prepared simply by the self-cross-linking of thiolated hyaluronic acid. Upon exposure to H2S which were excreted by surrounding intestinal pathogens, the hydrogel can locally degrade and rapidly release cargos to compete with source pathogens in turn for binding to the host. The mechanical properties of hydrogel were studied by rheological analysis, and the ideal stability was achieved at a polymer concentration of 4% (w/v). The morphology of the optimal encapsulation system was further measured by a scanning electron microscope, exhibiting uniform payload of probiotics. Endurance experiments indicated that the encapsulation of L. rhamnosus significantly enhanced their viability under gastrointestinal tract insults. Compared with free cells, encapsulated L. rhamnosus exerted better therapeutic effect against Salmonella-induced enteritis with negligible toxicity in vivo. These results demonstrate that this redox-responsive hydrogel may be a promising encapsulation and delivery system for improving the efficacy of orally administered probiotics.

Hyaluronic acid-coated ZIF-8 for the treatment of pneumonia caused by methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of hospital infection. Here, we showed that hyaluronic acid modified organic metal framework material ZIF-8 could be a Trojan horse of vancomycin (Van) for effective treatment of MRSA infections. The Van-loaded nanoparticles were readily up-taken by macrophages via a CD44-mediated process and collapsed in the acidic condition of endosome/lysosome, as a consequence, it could eradicate MRSA with high efficiency in macrophages. This drug delivery system with negligible toxicity could resolve MRSA infections in a well-established mouse pneumonia model.

Hyaluronic acid-based levofloxacin nanomicelles for nitric oxide-triggered drug delivery to treat bacterial infections.

Antibiotics are powerful weapons to fight against bacterial infections, while most of them lack of selective targeting towards pathological site which could restrict their antibacterial efficacy. To overcome this challenge, an antimicrobial levofloxacin(LF)was conjugated onto hyaluronic acid (HA) moieties via an o-phenylenediamine linker to prepare a NO-sensitive nanosystem (HA-NO-LF) in this study. The HA-NO-LF nanomicelles could enter host cells via a CD44 mediated endocytosis and release drug gradually upon exposure to endogenous NO. Furthermore, the more promising therapeutic effect of the nanomicelles in ameliorating inflammatory levels was observed in a mouse pneumonia model than that of LF. These results suggest that the HA-NO-LF nanomicelles may exert potent curative effect in infectious diseases.

Pathogen-targeting glycovesicles as a therapy for salmonellosis.

Antibiotic therapy is usually not recommended for salmonellosis, as it is associated with prolonged fecal carriage without reducing symptom duration or severity. Here we show that antibiotics encapsulated in hydrogen sulfide (H2S)-responsive glycovesicles may be potentially useful for the treatment of salmonellosis. The antibiotics are released in the presence of Salmonella, which is known to produce H2S. This approach prevents the quick absorption of antibiotics into the bloodstream, allows localized targeting of the pathogen in the gut, and alleviates disease symptoms in a mouse infection model. In addition, it reduces antibiotic-induced changes in the gut microbiota, and increases the abundance of potentially beneficial lactobacilli due to the release of prebiotic xylooligosaccharide analogs.

Versatile Chlorin e6-based magnetic polydopamine nanoparticles for effectively capturing and killing MRSA.

Bacterial infections are a growing global challenge for public health as antibiotic resistance could cause the failure of anti-infective treatment eventually. So, it is urgent to develop new potential antibacterial materials. Herein, a multifunctional chitosan (CS) functionalized magnetic Chlorin e6 (CS-MP-Ce6) was constructed to combat methicillin-resistant Staphylococcus aureus (MRSA) infection by integrating bacterial conjugation and enrichment, and near-infrared (NIR)-triggered photodynamic sterilization. CS-MP-Ce6 could efficiently capture bacteria due to positively charged property of CS, and Ce6 acted as an effective photodynamic killer to convert NIR light into local energy to enhance antibacterial activity. Specifically, after being trapped together with MRSA, CS-MP-Ce6 showed an excellent in vitro photodynamic sterilization ability. In vivo MRSA-induced abscess treatment studies showed faster healing when CS-MP-Ce6 was used as subcutaneous nano-localized energy sources with the assistance of external magnet to concentrate CS-MP-Ce6-bacteria conjugate. This work provides a promising framework for constructing a new system for efficiently combating MRSA.

Synergistic clearance of intracellular pathogens by hyaluronan-streptomycin micelles encapsulated with rapamycin.

Many pathogenic bacteria can invade phagocytic and non-phagocytic cells and colonize inside, which protects them from the attack by host immune system and antibiotics. A novel amphiphilic molecule was synthesized through conjugation of streptomycin and decylamine to hyaluronan. Rapamycin was encapsulted by the spontaneous self-assembly of hyaluronan-based amphiphilic molecules. The newly formed micelles not only facilitated the entry of drugs into host cells in part via CD44 phagocytic receptor, released streptomycin in the acidic compartment, but also could activate autophagy. The micelles elicited an efficient killing capacity against intracellular bacteria through the promotion of streptomycin uptake and rapamycin-initiated activation of autophagy. This strategy might highlight an acid-sensitive hyaluronan-based drug delivery system for effective treatment of intracellular infections.

Light controllable chitosan micelles with ROS generation and essential oil release for the treatment of bacterial biofilm.

Bacterial biofilms are widely associated with persistent infections and food contamination. High resistance to conventional antimicrobial agents resulted in an urgent need for novel formulation to eliminate these bacterial communities. Herein we fabricated light controllable chitosan micelles loading with thymol (T-TCP) for elimination of biofilm. Due to the exterior chitosan, T-TCP micelles easily bind to negative biofilm through electrostatic interaction and efficiently deliver the essential oil payloads. Under irradiation, T-TCP micelles generated ROS, which triggered simultaneous thymol release and also resulted in additional ROS-inducing bactericidal effects, both effectively eradicating biofilms of Listeria monocytogenes and Staphylococcus aureus. This formulation provided a platform for other water-insoluble antimicrobials and might be used as a potent and controllable solution to biofilm fighting.

A photo-controlled hyaluronan-based drug delivery nanosystem for cancer therapy.

In this paper, a novel photo-controlled drug-loaded nanomicelles were self-assembled by the amphiphile of hyaluronan-o-nitrobenzyl-stearyl chain (HA-NB-SC) with doxorubicin (DOX) encapsulated within the hydrophobic core. DOX-loaded HA-NB-SC nanomicelles are ∼139 nm in diameter. CD44-overexpressed HeLa cells can easily take up HA-NB-SC micelles through recognition of HA moiety. DOX-loaded HA-NB-SC nanomicelles could be disassembled upon UV light (365 nm) and consequently, release DOX at desired pathological sites. Furtherly, nitrosobenzaldehyde derivative, photo-induced products of HA-NB-SC and DOX could inhibit the proliferation of HeLa cells together. This strategy may shed some light on delivery of hydrophobic anti-cancer drugs in a controlled manner.

Inulin based glutathione-responsive delivery system for colon cancer treatment.

Colorectal cancer is one of the most common types of tumor in the world. Here we developed a lipoic acid esterified polysaccharide (inulin) delivery system for tanshinone IIA to treat colorectal cancer in vitro. The release of tanshinone IIA in the system was highly responsive to glutathione, which is commonly abundant in cancer cells. In addition, this drug delivery system was proliferative to Bifidobacterium longum, the common inhabitant of human intestine. Thus, this strategy might be useful to improve colon cancer therapy efficacy of anticancer drugs and meanwhile promote the growth of beneficial commensal flora in the gut.

A tanshinone I derivative enhances the activities of antibiotics against Staphylococcus aureus in vitro and in vivo.

Infections caused by Staphylococcus aureus are prevalent. The dramatically reduced discovery of new antibiotics, as well as the persistent emergence of resistant bacteria, represents a major health problem in both hospital and community settings. Using antibiotic enhancers to rescue existing classes of antibiotics is an attractive strategy. In this study, 16-aldehyde tanshinone I (ALT) was synthesized and bacteriostatic activity was explored. In addition, synergistic or additive activity between ALT and aminoglycoside antibiotics or ß-lactam antibiotics in vitro was identified. Moreover, ALT was documented to augment clearance of streptomycin (STR) and ampicillin (AMP) against S. aureus in a murine infection model. Primary mechanistic insight indicated that ALT could damage the bacterial cell membrane, leading to accumulation of antibiotics inside bacterial cells. This finding might be useful for treating infections caused by S. aureus and expand the scope of application of tanshinones.

N-[2-chloro-9H-purin-6-yl]-N-cyclopropylglycylamino acids and derivatives: synthesis, evaluation as a class of novel analgesics, and 3D QSAR analysis.

Via a five-step-reaction procedure for the preparation of 19 known N-[2-chloro-9-(tetrahydropyran-2-yl)-9H-purin-6-yl]-N-cyclopropylglycylamino acid benzylesters (6a-s) and successive removal of 9-(tetrahydropyran-2-yl) and benzylester groups 19 novel N-[2-chloro-9H-purin-6-yl]-N-cyclopropylglycylamino acid benzylesters (7a-s) and 19 novel N-[2-chloro-9H-purin-6-yl]-N-cyclopropylglycylamino acids (8a-s) were provided. On tail-flick mouse model the in vivo analgesic activities of these 38 novel compounds were measured and most of them were defined as good analgesics. Based on Molecular Field Analysis of the pain threshold variations of the mice receiving 48 compounds in terms of the descriptors proton and methyl an equation was established. The data points (n), correlation coefficient (r), and square correlation coefficient (r(2)) of this equation were 48, 0.923, and 0.852, respectively. Using this equation pain threshold variations of 9 compounds were predicted and the errors ranged from 1.71 to 8.92.