One-Dimensional Rod-like Tobacco Mosaic Virus Promotes Macrophage Polarization for a Tumor-Suppressive Microenvironment.

The phenotype of tumor-associated macrophages plays an important role in their function of regulating the tumor immune microenvironment. The M1-phenotype macrophages display tumor-killing and immune activating functions. Here we show that the tobacco mosaic virus (TMV), a rod-like plant virus, can polarize macrophages to an M1 phenotype and shape a tumor-suppressive microenvironment. RAW 264.7 cells and bone marrow derived-macrophages (BMDMs) can recognize TMV via Toll-like receptor-4, and then the MAPK and NF-κB signaling pathways are activated, leading to the production of pro-inflammatory factors. Furthermore, the in vivo assessments on a subcutaneous co-injection tumor model show that the TMV-polarized BMDMs shape a tumor-suppressive microenvironment, resulting in remarkable delay of 4T1 tumor growth. Another in vivo assessment on an established tumor model indicates the high tumor-metastasis-inhibiting capacity of TMV-polarized BMDMs. This work suggests a role for this plant virus in macrophage-mediated therapeutic approaches and provides a strategy for tumor immunotherapy.

Conjugating Peptides onto 1D Rodlike Bionanoparticles for Enhanced Activity against Gram-Negative Bacteria.

Gram-negative bacteria, which possess an impermeable outer membrane, are responsible for many untreatable infections. The lack of development of new relevant antibiotics for over 50 years has increased threats. Peptides are regarded as the most promising alternatives to antibiotics. However, since the activities of existing peptides are not yet comparable to those of current antibiotics, there is an urgent need to improve their antibacterial efficiencies. Herein, we conjugate peptides onto one-dimensional rod-like tobacco mosaic virus (TMV). The peptides on the obtained nanoparticles (peptide-TMV) are hundreds of times superior to free peptides in combating Gram-negative bacteria. Through morphology and gene detection of Escherichia coli, it was revealed that following peptide-TMV application, the high osmotic pressure related to membrane damage and the generated reactive oxygen species cause Escherichia coli's death. In addition, peptide-TMV causes a downregulation of biofilm-related genes, inhibiting biofilm formation. This work paves the way to combat Gram-negative bacteria-related infection.

Solid-Phase Extraction of Hemoglobin from Human Whole Blood with a Coordination-Polymer-Derived Composite Material Based on ZnO and Mesoporous Carbon.

A composite material, ZnO@MC, has been synthesized successfully by calcination using a one-dimensional zinc-based coordination polymer as the precursor. In ZnO@MC, ZnO particles with a size of about 5-8 nm are dispersed evenly in a mesoporous carbon matrix. Adsorption experiments at pH 6.8 with 2 mg ZnO@MC as adsorbent illustrated an adsorption efficiency of 92.3 % in 5 mL hemoglobin (Hb) solution with a concentration of 100 mg L-1 . In contrast, the adsorption of bovine serum albumin can almost be ignored under the same conditions. The selectivity originates from a strong ZnII -histidine interaction between ZnO@MC and hemoglobin. The adsorption behavior of hemoglobin on ZnO@MC fits the Temkin model perfectly with a capacity as high as 11646 mg g-1 . The hemoglobin adsorbed on the composite material can be eluted easily with sodium dodecyl sulfate stripping reagent with an extraction efficiency of 87.7 %. Circular dichroism spectra and protein activity studies suggest the structure and biological activity of hemoglobin is the same before and after the adsorption/desorption experiment. Finally, the ZnO@MC composite material was employed to extract hemoglobin from human whole blood without any pretreatment, and gave a very satisfactory result.

Multi-responsive sodium hyaluronate/tannic acid hydrogels with ROS scavenging ability promote the healing of diabetic wounds.

Oxidative stress caused by excessive reactive oxygen species (ROS) accumulation significantly hinders wound healing in patients with diabetes. Scavenging ROS and reducing inflammation are crucial for rapid healing. In this work, a multi-responsive sodium hyaluronate (HA)/tannic acid (TA) hydrogel was developed based on boronate ester bonds. Sodium hyaluronate with 3-aminophenyl boronic acid modification (HA-APBA) was mixed and crosslinked with TA to form HA-APBA/TA hydrogels. These hydrogels are injectable, self-healing, and biocompatible. The HA-APBA/TA hydrogels could release free TA through the collapse of the structure at low pH, high H2O2 concentration, and high glucose concentration, thus possessing good ROS scavenging ability. In full-thickness skin wounds of db/db mice, the HA-APBA/TA hydrogels promoted wound healing, collagen deposition, and significant angiogenesis. Furthermore, they have been shown to effectively reduce the levels of inflammatory factors in wounds and lower the expression of CD86, a pro-inflammatory macrophage surface marker. This resulted in a more effective transition of wound healing from the inflammatory phase to the proliferative phase. This study provides an optional strategy for alleviating oxidative stress and controlling excessive inflammation, thereby promoting diabetic wound healing.

Histatin 5-Inspired Short-Chain Peptides Selectively Combating Pathogenic Fungi with Multifaceted Mechanisms.

Short-chain antifungal peptides (AFPs) inspired by histatin 5 have been designed to address the problem of antifungal drug resistance. These AFPs demonstrate remarkable antifungal activity, with a minimal inhibitory concentration as low as 2 µg mL-1. Notably, these AFPs display a strong preference for targeting fungi rather than bacteria and mammalian cells. This is achieved by binding the histidine-rich domains of the AFPs to the Ssa1/2 proteins in the fungal cell wall, as well as the reduced membrane-disrupting activity due to their low amphiphilicity. These peptides disrupt the nucleus and mitochondria once inside the cells, leading to reactive oxygen species production and cell damage. In a mouse model of vulvovaginal candidiasis, the AFPs demonstrate not only antifungal activity, but also promote the growth of beneficial Lactobacillus spp. This research provides valuable insights for the development of fungus-specific AFPs and offers a promising strategy for the treatment of fungal infectious diseases.

Escherichia coli exopolysaccharides disrupt Pseudomonas aeruginosa biofilm and increase its antibiotic susceptibility.

Pseudomonas aeruginosa (P. aeruginosa) is a major pathogen that causes infectious diseases. It has high tendency to form biofilms, resulting in the failure of traditional antibiotic therapies. Inspired by the phenomenon that co-culture of Escherichia coli (E. coli) and P. aeruginosa leads to a biofilm reduction, we reveal that E. coli exopolysaccharides (EPS) can disrupt P. aeruginosa biofilm and increase its antibiotic susceptibility. The results show that E. coli EPS effectively inhibit biofilm formation and disrupt mature biofilms in P. aeruginosa, Staphylococcus aureus, and E. coli itself. The maximal inhibition and disruption rates against P. aeruginosa biofilm are 40 % and 47 %, respectively. Based on the biofilm-disrupting ability of E. coli EPS, we develop an E. coli EPS/antibiotic combining strategy for the treatment of P. aeruginosa biofilms. The combination with E. coli EPS increases the antibacterial efficiency of tobramycin against P. aeruginosa biofilms in vitro and in vivo. This study provides a promising strategy for treating biofilm infections. STATEMENT OF SIGNIFICANCE: Biofilm formation is a leading cause of chronic infections. It blocks antibiotics, increases antibiotic-tolerance, and aids in immune evasion, thus representing a great challenge in clinic. This study proposes a promising approach to combat pathogenic Pseudomonas aeruginosa (P. aeruginosa) biofilms by combining Escherichia coli exopolysaccharides with antibiotics. This strategy shows high efficiency in different P. aeruginosa stains, including two laboratory strains, PAO1 and ATCC 10145, as well as a clinically acquired carbapenem-resistant strain. In addition, in vivo experiments have shown that this approach is effective against implanted P. aeruginosa biofilms and can prevent systemic inflammation in mice. This strategy offers new possibilities to address the clinical failure of conventional antibiotic therapies for microbial biofilms.

A conserved antigen induces respiratory Th17-mediated broad serotype protection against pneumococcal superinfection.

Several vaccines targeting bacterial pathogens show reduced efficacy upon concurrent viral infection, indicating that a new vaccinology approach is required. To identify antigens for the human pathogen Streptococcus pneumoniae that are effective following influenza infection, we performed CRISPRi-seq in a murine model of superinfection and identified the conserved lafB gene as crucial for virulence. We show that LafB is a membrane-associated, intracellular protein that catalyzes the formation of galactosyl-glucosyl-diacylglycerol, a glycolipid important for cell wall homeostasis. Respiratory vaccination with recombinant LafB, in contrast to subcutaneous vaccination, was highly protective against S. pneumoniae serotypes 2, 15A, and 24F in a murine model. In contrast to standard capsule-based vaccines, protection did not require LafB-specific antibodies but was dependent on airway CD4+ T helper 17 cells. Healthy human individuals can elicit LafB-specific immune responses, indicating LafB antigenicity in humans. Collectively, these findings present a universal pneumococcal vaccine antigen that remains effective following influenza infection.

Surface decoration with leucine tetrapeptide: An antibacterial strategy against Gram-negative bacteria.

Surface-associated microbe contamination by Gram-negative bacteria poses a serious problem in medical care. Cationic peptides or polymers are the main materials used for antibacterial surface coating, but the positive charge may lead to blood coagulation. Therefore, exploiting surface coating which is free of positive charge and is effective for Gram-negative bacteria inactivation is in urgent need. In this study, inspired by the affinity between lipopolysaccharides of Gram-negative bacteria and Toll-like receptors of immune cells, we develop a leucine-based tetrapeptide coating strategy for combating Gram-negative bacteria. The obtained surface has excellent bactericidal activity against Gram-negative bacteria like Pseudomonas aeruginosa and Escherichia coli. A 1 mm2 coated glass surface could kill > 9.9 × 104 CFU bacteria in 1 h and has nearly no damage to mammal cells. Moreover, this surface coating strategy could be applied on various surfaces like glass slices, glass capillary cavity and thermoplastic polyurethane slices. And the coated surface could largely mitigate the microbe contamination in an in vivo subcutaneous implantation. This work paves a new way for antibacterial surface-coating which is behaving no positive charge and is of great importance for biomedical devices.

Combating Pseudomonas aeruginosa Biofilms by a Chitosan-PEG-Peptide Conjugate via Changes in Assembled Structure.

Pseudomonas aeruginosa (P. aeruginosa) biofilms are associated with a wide range of infections, from chronic tissue diseases to implanted medical devices. In a biofilm, the extracellular polymeric substance (EPS) causes an inhibited penetration of antibacterial agents, leading to a 100-1000 times tolerance of the bacteria. In view of the water-filled channels in biofilms and the highly negative charge of EPS, we design a chitosan-polyethylene glycol-peptide conjugate (CS-PEG-LK13) in this study. The CS-PEG-LK13 prefers a neutrally charged assembly at a size of ∼100 nm in aqueous environment, while undergoes disassembly to expose the α-helical peptide at the bacterial cell membrane. This behavior provides CS-PEG-LK13 superiorities in both penetrating the biofilms and inactivating the bacteria. At a concentration of 8 times the minimum inhibitory concentration, CS-PEG-LK13 has a much higher antibacterial efficiency (72.70%) than LK13 peptide (15.24%) and tobramycin (33.57%) in an in vitro P. aeruginosa biofilm. Moreover, CS-PEG-LK13 behaves comparable capability of combating an implanted P. aeruginosa biofilm to highly excess tobramycin. This work has implications for the design of new antibacterial agents in biofilm combating.

The loading of coordination complex modified polyoxometalate nanobelts on activated carbon fiber: a feasible strategy to obtain visible light active and highly efficient polyoxometalate based photocatalysts.

To enhance the photocatalytic properties of coordination complex modified polyoxometalates (CC/POMs) in the visible light region, its nanobelts (CC/POMNBs) were loaded on activated carbon fiber (ACF) through a simple colloidal blending process. The resulting coordination complex modified polyoxometalate nanobelts loaded activated carbon fiber composite materials (CC/POMNBs/ACF) exhibited dramatic photocatalytic activity for the degradation of rhodamine B (RhB) under visible light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CC/POMNBs/ACF, which originates from the high separation efficiency of the photogenerated electrons and holes on the interface of the CC/POMNBs and ACF, which results from the synergistic effects between them. In the composite material, the role of ACF could be described as a photosensitizer and a good electron transporter. Furthermore, the influence of the mass ratio between the CC/POMNBs and ACF on the photocatalytic performance of the resulting composite material was discussed, and an ideal value to obtain highly efficient photocatalysts was obtained. The results suggested that the loading of CC/POMNBs on the surface of ACF would be a feasible strategy to enhance their photocatalytic activity.