Gallnut tannic acid alleviates gut damage induced by Salmonella pullorum in broilers by enhancing barrier function and modulating microbiota.

Pullorum disease (PD) is a bacterial infection caused by Salmonella pullorum (S. pullorum) that affects poultry. It is highly infectious and often fatal. Antibiotics are currently the mainstay of prophylactic and therapeutic treatments for PD, but their use can lead to the development of resistance in pathogenic bacteria and disruption of the host's intestinal flora. We added neomycin sulfate and different doses of tannic acid (TA) to the drinking water of chicks at 3 days of age and infected them with PD by intraperitoneal injection of S. pullorum at 9 days of age. We analyzed intestinal histopathological changes and the expression of immune-related genes and proteins by using the plate smear method, histological staining, real-time fluorescence quantitative PCR, ELISA kits, and 16S rRNA Analysis of intestinal flora. The results demonstrate that S. pullorum induces alterations in the immune status and impairs the functionality of the liver and intestinal barrier. We found that tannic acid significantly ameliorated S. pullorum-induced liver and intestinal damage, protected the intestinal physical and chemical barriers, restored the intestinal immune barrier function, and regulated the intestinal flora. Our results showed that TA has good anti-diarrhoeal, growth-promoting, immune-regulating, intestinal barrier-protecting and intestinal flora-balancing effects, and the best effect was achieved at an additive dose of 0.2%.

Pathogen-Mimicking Nanoparticles Based on Rigid Nanomaterials as an Efficient Subunit Vaccine Delivery System for Intranasal Immunization.

Despite the safety profile of subunit vaccines, the inferior immunogenicity hinders their application in the nasal cavity. This study introduces a novel antigen delivery and adjuvant system utilizing mucoadhesive chitosan-catechol (Chic) on silica spiky nanoparticles (Ssp) to enhance immunity through multiple mechanisms. The Chic functionalizes the Ssp surface and incorporates with SARS-CoV-2 spike protein receptor-binding domain (RBD) and toll-like receptor (TLR)9 agonist unmethylated cytosine-guanine (CpG) motif, forming uniform virus-like nanoparticles (Ssp-Chic-RBD-CpG) via electrostatic and covalent interactions. Ssp-Chic-RBD-CpG, mimicking the morphology and function of inactive virions, effectively prolongs the retention time of RBD in the nasal mucosa by 3.92-fold compared to RBD alone, enhances the maturation of dendritic cells (DCs), and facilitates the antigen trafficking to the draining lymph nodes, which subsequently induces a stronger mucosal immunity. Mechanistically, the enhanced chemokine chemokine (C-C motif) ligand 20 (CCL20)-driven DCs recruitment and maturation by Ssp-Chic-RBD-CpG are evidenced by a cell co-culture model. In addition, the overexpression of TLR4/9 and activation of MYD88/NF-κB signaling pathway in activation of DCs are observed. Proof of principle is obtained for RBD, but similar delivery mechanisms can be applied in other protein-based subunit vaccines as well when intranasal administration is needed.

Mucoadhesive chitosan-catechol as an efficient vaccine delivery system for intranasal immunization.

The mucosal barrier and scavenging effect of the mucosal layer are two main obstacles in inducing mucosal immunization. To overcome these obstacles, we synthesized a bio-inspired mucoadhesive material, chitosan-catechol (ChiC), for surface modification of inactive porcine epidemic diarrhea virus (PEDV). Studies have revealed that PEDV particles can be facilely and mildly modified by Chi-C forming Chi-C-PEDV nanoparticles (Chic-Ps) through the covalent and electrostatic bond, which effectively prolongs the retention time of PEDV in the nasal mucosa. The cell co-culture model demonstrated that Chic-Ps exhibit enhanced recruitment of dendritic cells via the secretion of stimulating chemokine CCL20 and improving antigen permeability by disruption the distribution of ZO-1 protein in epithelial cells. Additionally, the flow cytometry (FCM) analysis revealed that Chic-Ps facilitate trafficking to lymph nodes and induce stronger cellular and humoral immune responses compared to unmodified PEDV. Notably, Chic-Ps induced a higher level of PEDV neutralizing antibody was induced by Chic-Ps in the nasal washes, as confirmed by a plaque reduction neutralization test. These results demonstrate that Chi-C is a promising nasal delivery system for vaccines. Proof of principle was obtained for inactivated PEDV, but similar delivery mechanisms could be applied in other vaccines when intranasal administration is needed.

Guiding antibiotics towards their target using bacteriophage proteins.

Novel therapeutic strategies against difficult-to-treat bacterial infections are desperately needed, and the faster and cheaper way to get them might be by repurposing existing antibiotics. Nanodelivery systems enhance the efficacy of antibiotics by guiding them to their targets, increasing the local concentration at the site of infection. While recently described nanodelivery systems are promising, they are generally not easy to adapt to different targets, and lack biocompatibility or specificity. Here, nanodelivery systems are created that source their targeting proteins from bacteriophages. Bacteriophage receptor-binding proteins and cell-wall binding domains are conjugated to nanoparticles, for the targeted delivery of rifampicin, imipenem, and ampicillin against bacterial pathogens. They show excellent specificity against their targets, and accumulate at the site of infection to deliver their antibiotic payload. Moreover, the nanodelivery systems suppress pathogen infections more effectively than 16 to 32-fold higher doses of free antibiotics. This study demonstrates that bacteriophage sourced targeting proteins are promising candidates to guide nanodelivery systems. Their specificity, availability, and biocompatibility make them great options to guide the antibiotic nanodelivery systems that are desperately needed to combat difficult-to-treat infections.

Extraction, characterization and intestinal anti-inflammatory and anti-oxidative activities of polysaccharide from stems and leaves of Chuanminshen violaceum M. L. Sheh & R. H. Shan.

ETHNOPHARMACOLOGICAL RELEVANCE: Chuanminshen violaceum M. L. Sheh & R. H. Shan (CV) is used as a medicine with roots, which have the effects of benefiting the lungs, harmonizing the stomach, resolving phlegm and detoxifying. Polysaccharide is one of its main active components and has various pharmacological activities, but the structural characterization and pharmacological activities of polysaccharide from the stems and leaves parts of CV are still unclear. AIM OF THE STUDY: The aim of this study was to investigate the optimal extraction conditions for ultrasound-assisted extraction of polysaccharide from CV stems and leaves, and to carry out preliminary structural analyses, anti-inflammatory and antioxidant effects of the obtained polysaccharide and to elucidate the underlying mechanisms. MATERIALS AND METHODS: The ultrasonic-assisted extraction of CV stems and leaves polysaccharides was carried out, and the response surface methodology (RSM) was used to optimize the extraction process to obtain CV polysaccharides (CVP) under the optimal conditions. Subsequently, we isolated and purified CVP to obtain the homogeneous polysaccharide CVP-AP-I, and evaluated the composition, molecular weight, and structural features of CVP-AP-I using a variety of technical methods. Finally, we tested the pharmacological activity of CVP-AP-Ⅰ in an LPS-induced model of oxidative stress and inflammation in intestinal porcine epithelial cells (IPEC-J2) and explored its possible mechanism of action. RESULTS: The crude polysaccharide was obtained under optimal extraction conditions and subsequently isolated and purified to obtain CVP-AP-Ⅰ (35.34 kDa), and the structural characterization indicated that CVP-AP-Ⅰ was mainly composed of galactose, galactose, rhamnose and glucose, which was a typical pectic polysaccharide. In addition, CVP-AP-Ⅰ attenuates LPS-induced inflammation and oxidative stress by inhibiting the expression of pro-inflammatory factor genes and proteins and up-regulating the expression of antioxidant enzyme-related genes and proteins in IPEC-J2, by a mechanism related to the activation of the Nrf2/Keap1 signaling pathway. CONCLUSION: The results of this study suggest that the polysaccharide isolated from CV stems and leaves was a pectic polysaccharide with similar pharmacological activities as CV roots, exhibiting strong anti-inflammatory and antioxidant activities, suggesting that CV stems and leaves could possess the same traditional efficacy as CV roots, which is expected to be used in the treatment of intestinal diseases.

Rat Hepatocytes Protect against Lead-Cadmium-Triggered Apoptosis Based on Autophagy Activation.

Lead and cadmium are foodborne contaminants that threaten human and animal health. It is well known that lead and cadmium produce hepatotoxicity; however, defense mechanisms against the co-toxic effects of lead and cadmium remain unknown. We investigated the mechanism of autophagy (defense mechanism) against the co-induced toxicity of lead and cadmium in rat hepatocytes (BRL-3A cells). Cultured rat liver BRL-3A cell lines were co-cultured with 10, 20, 40 µM lead and 2.5, 5, 10 µM cadmium alone and in co-culture for 12 h and exposed to 5 mM 3-Methyladenine (3-MA), 10 µM rapamycin (Rapa), and 50 nM Beclin1 siRNA to induce cellular autophagy. Our results show that treatment of BRL-3A cells with lead and cadmium significantly decreased the cell viability, increased intracellular reactive oxygen species levels, decreased mitochondrial membrane potential levels, and induced apoptosis, which are factors leading to liver injury, and cell damage was exacerbated by co-exposure to lead-cadmium. In addition, the results showed that lead and cadmium co-treatment induced autophagy. We further observed that the suppression of autophagy with 3-MA or Beclin1 siRNA promoted lead-cadmium-induced apoptosis, whereas enhancement of autophagy with Rapa suppressed lead-cadmium-induced apoptosis. These results demonstrated that co-treatment with lead and cadmium induces apoptosis in BRL-3A cells. Interestingly, the activation of autophagy provides cells with a self-protective mechanism against induced apoptosis. This study provides insights into the role of autophagy in lead-cadmium-induced apoptosis, which may be beneficial for the treatment of lead-cadmium-induced liver injury.

Ultrasonic-assisted extraction of polysaccharide from Paeoniae Radix alba: Extraction optimization, structural characterization and antioxidant mechanism in vitro.

Paeoniae Radix alba is used in Traditional Chinese Medicine for the treatment of gastrointestinal disorders, immunomodulatory, cancer, and other diseases. In the current study, the yield of Paeoniae Radix alba polysaccharide (PRP) was significantly increased with optimal ultrasound-assisted extraction compared to hot water extraction. Further, an acidic polysaccharide (PRP-AP) was isolated from PRP after chromatographic separation and was characterized as a typical pectic polysaccharide with side chains of arabinogalactans types I and II. Moreover, it showed antioxidant effects on LPS-induced damage on IPEC-J2 cells determined by qRT-PCR and ELISA, including decreasing the pro-inflammatory factors' expressions and increasing the antioxidant enzymes activities, which was shown to be related to the Nrf2/Keap1 pathway modulated by PRP-AP. The metabolites change (such as itaconate, cholesterol sulfate, etc.) detected by untargeted metabolomic analysis in cells was also shown to be modulated by PRP-AP, and these metabolites were further utilized and protected cells damaged by LPS. These results revealed the cellular active mechanism of the macromolecular PRP-AP on protecting cells, and supported the hypothesis that PRP-AP has strong benefits as an alternative dietary supplement for the prevention of intestinal oxidative stress by modulating cellular metabolism.

A supramolecular hydrogel dressing with antibacterial, immunoregulation, and pro-regeneration ability for biofilm-associated wound healing.

Chronic wound treatment has emerged as a significant healthcare concern worldwide due to its substantial economic burden and the limited effectiveness of current treatments. Effective management of biofilm infections, regulation of excessive oxidative stress, and promotion of tissue regeneration are crucial for addressing chronic wounds. Hydrogel stands out as a promising candidate for chronic wound treatment. However, its clinical application is hindered by the difficulty in designing and fabricating easily and conveniently. To overcome these obstacles, we present a supermolecular G-quadruplex hydrogel with the desired multifunction via a dynamic covalent strategy and Hoogsteen-type hydrogen bonding. The G-quadruplex hydrogel is made from the self-assembly of guanosine, 2-formylphenyboronic acid, polyethylenimine, and potassium chloride, employing dynamic covalent strategy and Hoogsteen-type hydrogen bonding. In the acidic/oxidative microenvironment associated with bacterial infections, the hydrogel undergoes controlled degradation, releasing the polyethylenimine domain, which effectively eliminates bacteria. Furthermore, nanocomplexes comprising guanosine monophosphate and manganese sulfate are incorporated into the hydrogel skeleton, endowing it with the ability to scavenge reactive oxygen species and modulate macrophages. Additionally, the integration of basic fibroblast growth factor into the G-quadruplex skeleton through dynamic covalent bonds facilitates controlled tissue regeneration. In summary, the facile preparation process and the incorporation of multiple functionalities render the G-quadruplex hydrogel a highly promising candidate for advanced wound dressing. It holds great potential to transition from laboratory research to clinical practice, addressing the pressing needs of chronic wound management.

Eriodictyol Alleviated LPS/D-GalN-Induced Acute Liver Injury by Inhibiting Oxidative Stress and Cell Apoptosis via PI3K/AKT Signaling Pathway.

Eriodictyol occurs naturally in a variety of fruits and vegetables, and has drawn significant attention for its potential health benefits. This study aims to look into the effects of eriodictyol on acute liver injury (ALI) induced by LPS/D-GalN and elucidate its potential molecular biological mechanisms. A total of 47 targets were predicted for the treatment of ALI with eriodictyol, and the PI3K/AKT signaling pathway played a key role in the anti-ALI processing of this drug. The in vivo experiment showed that eriodictyol can effectively reduce liver function-related biochemical indicators such as ALT, AST, and AKP. Eriodictyol can also up-regulate the levels of SOD and GSH, and inhibit the release of IL-1ß, IL-6, and TNF-α. Additionally, TUNEL staining, immunohistochemistry, and RT-PCR experiments showed that eriodictyol activated the PI3K/AKT pathway and decreased the expression of Bax, caspase3, and caspase8 while increasing the expression of Bcl-2 m-RNA. Finally, molecular docking experiments and molecular dynamics simulations confirmed the stable binding between eriodictyol and PI3K, AKT molecules. This study showed that eriodictyol can activate the PI3K/AKT signaling pathway to alleviate ALI-related oxidative stress and apoptosis.

Seeing the Invisibles: Detection of Peptide Enantiomers, Diastereomers, and Isobaric Ring Formation in Lanthipeptides Using Nanopores.

Mass spectrometry (MS) is widely used in proteomic analysis but cannot differentiate between molecules with the same mass-to-charge ratio. Nanopore technology might provide an alternative method for the rapid and cost-effective analysis and sequencing of proteins. In this study, we demonstrate that nanopore currents can distinguish between diastereomeric and enantiomeric differences in l- and d-peptides, not observed by conventional MS analysis, down to individual d-amino acids in small opioid peptides. Molecular dynamics simulations suggest that similar to chiral chromatography the resolution likely arises from multiple chiral interactions during peptide transport across the nanopore. Additionally, we used nanopore recordings to rapidly assess 4- and 11-amino acid ring formation in lanthipeptides, a process used in the synthesis of pharmaceutical peptides. The cyclization step requires distinguishing between constitutional isomers, which have identical MS signals and typically involve numerous tedious experiments to confirm. Hence, nanopore technology offers new possibilities for the rapid and cost-effective analysis of peptides, including those that cannot be easily differentiated by mass spectrometry.

Low molecular weight fucoidan modified nanoliposomes for the targeted delivery of the anti-inflammation natural product berberine.

The inflammatory response is the basis of many diseases, such as atherosclerosis and ulcerative colitis. Inhibiting inflammatory response is the key to treating these diseases. Berberine hydrochloride (BBR), a natural product, has shown effective inflammation inhibitory activity. However, its distribution throughout the body results in a variety of serious side effects. Currently, there is a lack of targeted delivery systems for BBR to inflammatory sites. In view of the fact that the recruitment of inflammatory cells by activated vascular endothelial cells is a key step in inflammation development. Here, we design a system that can specifically deliver berberine to activated vascular endothelial cells. Low molecular weight fucoidan (LMWF), which can specifically bind to P-selectin, was coupled to PEGylated liposomes (LMWF-Lip), and BBR is encapsulated into LMWF-Lip (LMWF-Lip/BBR). In vitro, LMWF-Lip significantly increases the uptake by activated human umbilical vein endothelial cells (HUVEC). Injection of LMWF-Lip into the tail vein of rats can effectively accumulate in the swollen part of the foot, where it is internalized by the characteristics of activated vascular endothelial cells. LMWF-Lip/BBR can effectively inhibit the expression of P-selectin in activated vascular endothelial cells, and reduce the degree of foot edema and inflammatory response. In addition, compared with free BBR, the toxicity of BBR in LMWF-Lip/BBR to main organs was significantly reduced. These results suggest that wrapping BBR in LMWF-Lip can improve efficacy and reduce its systemic toxicity as a potential treatment for various diseases caused by inflammatory responses.

Exosomes from tannic acid-stimulated macrophages accelerate wound healing through miR-221-3p mediated fibroblasts migration by targeting CDKN1b.

Tannic acid (TA) and its extraction were traditionally used for treatment of traumatic bleeding in China, and in the previous study we have demonstrated that TA could accelerate cutaneous wound healing in rats. We attempted to decipher the mechanism of TA in promoting wound healing. In this study, we found that TA could enhance the growth of macrophages and inhibit the release of inflammatory cytokines (IL-1ß, IL-6, TNF-α, IL-8 and IL-10) through inhibition of NF-κB/JNK pathway. TA activated Erk1/2 pathway, leading to increased expressions of growth factors, bFGF and HGF. Scratch study revealed that TA did not directly regulate the migration function of fibroblasts, but could indirectly enhance fibroblasts migration by the supernatant of TA-treated macrophages. Transwell study further proved that TA stimulates macrophages to secrete exosomes enriched in miR-221-3p by activating the p53 signaling pathway, and the exosomes entered into the fibroblast cytoplasm and bound to 3'UTR of target gene CDKN1b which induced decreased expression level of CDKN1b, leading to promoting fibroblast migration. This study provided new insights into how TA accelerates wound healing in the inflammatory and proliferative phases of wound healing.

Preparation, characterization and protective effect of chitosan - Tripolyphosphate encapsulated dihydromyricetin nanoparticles on acute kidney injury caused by cisplatin.

Dihydromyricetin (DMY) is a natural dihydroflavonol compound known for its diverse pharmacological benefits. However, its limited stability and bioavailability posed significant challenges for further applications. To address these issues, in this study, an ion crosslinking method was utilized to prepare chitosan nanoparticles that were loaded with DMY. The synthesized chitosan nanoparticles (CS-DMY-NPs) were spherical in shape with particle size and ζ potential of 198.7 nm and 45.05 mV, respectively. Furthermore, in vitro release experiments demonstrated that CS-DMY-NPs had sustained release and protective effects in simulated gastric and intestinal fluids. CS-DMY-NPs exhibited better antioxidant activity by ABTS and DPPH radical scavenging activity than free DMY. In vivo study showed that CS-DMY-NPs alleviated cisplatin-induced kidney damage by inhibiting oxidative stress and proinflammatory cytokines, and had better activity compared to DMY (free). Immunofluorescence data showed that CS-DMY-NPs activated the Nrf2 signaling pathways in a dose-dependent manner to combat cisplatin-induced kidney damage. Our results demonstrate that CS-TPP has good compatibility with DMY, and CS-DMY-NPs exhibited better protective effects against cisplatin-induced acute kidney injury (AKI) than free DMY.

Swertia cincta Burkill alleviates LPS/D-GalN-induced acute liver failure by modulating apoptosis and oxidative stress signaling pathways.

Swertia cincta Burkill is widely distributed along the southwestern region of China. It is known as "Dida" in Tibetan and "Qingyedan" in Chinese medicine. It was used in folk medicine to treat hepatitis and other liver diseases. To understand how Swertia cincta Burkill extract (ESC) protects against acute liver failure (ALF), firstly, the active ingredients of ESC were identified using liquid chromatography-mass spectrometry (LC-MS), and further screening. Next, network pharmacology analyses were performed to identify the core targets of ESC against ALF and further determine the potential mechanisms. Finally, in vivo experiments as well as in vitro experiments were conducted for further validation. The results revealed that 72 potential targets of ESC were identified using target prediction. The core targets were ALB, ERBB2, AKT1, MMP9, EGFR, PTPRC, MTOR, ESR1, VEGFA, and HIF1A. Next, KEGG pathway analysis showed that EGFR and PI3K-AKT signaling pathways could have been involved in ESC against ALF. ESC exhibits hepatic protective functions via anti-inflammatory, antioxidant, and anti-apoptotic effects. Therefore, the EGFR-ERK, PI3K-AKT, and NRF2/HO-1 signaling pathways could participate in the therapeutic effects of ESC on ALF.

Polysaccharide from aerial part of Chuanminshen violaceum alleviates oxidative stress and inflammatory response in aging mice through modulating intestinal microbiota.

Aging is a biological process of progressive deterioration of physiological functions, which poses a serious threat to individual health and a heavy burden on public health systems. As population aging continues, research into anti-aging drugs that prolong life and improve health is of particular importance. In this study, the polysaccharide from stems and leaves of Chuanminshen violaceum was obtained with water extraction and alcohol precipitation, and then separated and purified with DEAE anion exchange chromatography and gel filtration to obtain CVP-AP-I. We gavaged natural aging mice with CVP-AP-I and performed serum biochemical analysis, histological staining, quantitative real-time PCR (qRT-PCR) and ELISA kit assays to analyze inflammation and oxidative stress-related gene and protein expression in tissues, and 16SrRNA to analyze intestinal flora. We found that CVP-AP-I significantly improved oxidative stress and inflammatory responses of the intestine and liver, restored the intestinal immune barrier, and balanced the dysbiosis of intestinal flora. In addition, we revealed the potential mechanism behind CVP-AP-I to improve intestinal and liver function by regulating intestinal flora balance and repairing the intestinal immune barrier to regulate the intestinal-liver axis. Our results indicated that C. violaceum polysaccharides possessed favorable antioxidant, anti-inflammatory and potentially anti-aging effects in vivo.

Angelica sinensis aboveground part polysaccharide and its metabolite 5-MT ameliorate colitis via modulating gut microbiota and TLR4/MyD88/NF-κB pathway.

The roots of Angelica sinensis have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this herb (aboveground part) are commonly discarded during the process of root preparations. A polysaccharide (ASP-Ag-AP) in the aboveground parts of A. sinensis was isolated and preliminarily characterized as typical plant pectin. ASP-Ag-AP exhibited noticeable protective effects against dextran sodium sulfate (DSS)-induced colitis, including reduction of colonic inflammation, modulation of barrier function, and alteration of gut microbiota and serum metabolite profile. Anti-inflammatory effects of ASP-Ag-AP were observed by inhibiting TLR4/MyD88/NF-κB signaling pathway in vitro and in vivo. Additionally, the level of serum metabolite 5-methyl-dl-tryptophan (5-MT) was reduced by DSS and restored by ASP-Ag-AP, which also negatively correlated with Bacteroides, Alistipes, Staphylococcus and pro-inflammatory factors. The protection from inflammatory stress on intestinal porcine enterocytes cells (IPEC-J2) of 5-MT was observed through the inhibition of TLR4/MyD88/NF-κB pathway. Besides, 5-MT also exhibited robust anti-inflammatory effect in colitis mice with improving colitis symptoms, barrier function and gut microbiota, which was the same as presented by ASP-Ag-AP. Therefore, ASP-Ag-AP could be a promising agent for colitis prevention and 5-MT could be the signal metabolite of ASP-Ag-AP on defending against intestinal inflammatory stress.

Elucidating the Mechanism of Action of the Gram-Negative-Pathogen-Selective Cyclic Antimicrobial Lipopeptide Brevicidine.

Due to the accelerated appearance of antimicrobial-resistant (AMR) pathogens in clinical infections, new first-in-class antibiotics, operating via novel modes of action, are desperately needed. Brevicidine, a bacterial nonribosomally produced cyclic lipopeptide, has shown potent and selective antimicrobial activity against Gram-negative pathogens. However, before our investigations, little was known about how brevicidine exerts its potent bactericidal effect against Gram-negative pathogens. In this study, we find that brevicidine has potent antimicrobial activity against AMR Enterobacteriaceae pathogens, with MIC values ranging between 0.5 µM (0.8 mg/L) and 2 µM (3.0 mg/L). In addition, brevicidine showed potent antibiofilm activity against the Enterobacteriaceae pathogens, with the same 100% inhibition and 100% eradication concentration of 4 µM (6.1 mg/L). Further mechanistic studies showed that brevicidine exerts its potent bactericidal activity by interacting with lipopolysaccharide in the outer membrane, targeting phosphatidylglycerol and cardiolipin in the inner membrane, and dissipating the proton motive force of bacteria. This results in metabolic perturbation, including the inhibition of ATP synthesis; the inhibition of the dehydrogenation of NADH; the accumulation of reactive oxygen species in bacteria; and the inhibition of protein synthesis. Finally, brevicidine showed a good therapeutic effect in a mouse peritonitis-sepsis model. Our findings pave the way for further research on the clinical applications of brevicidine to combat prevalent infections caused by AMR Gram-negative pathogens worldwide.

Resveratrol alleviated neuroinflammation induced by pseudorabies virus infection through regulating microglial M1/M2 polarization.

BACKGROUND: Pseudorabies virus (PRV) infections in susceptible non-porcine species trigger uncontrolled inflammations and eventually fatal encephalitis. Resveratrol (Res) has broad pharmacological functions including anti-virus, anti-inflammation, and neuroprotective. PURPOSE: We attempted to investigate the potential of Res in ameliorating PRV infection pathology in mice and decipher the mechanism of Res in treating PRV. METHODS: The mice were infected by PRV to investigate the protective effect of Res. Blood-brain barrier (BBB) permeability, H&E/Nissl/TUNEL staining, Real-time PCR and ELISA analyses were performed. Primary microglia and neuron were isolated from mice and cultured. The co-culture model of microglia and neuron was established by transwell. Immunofluorescence assay and flow cytometry were used. RESULTS: In this study, we showed that Res ameliorated brain damage by reducing BBB permeability in PRV-infected mice, and diminished the expressions of MMP-2, MMP-9 and ZO-1 in the cortex. Pathological changes of neurons by H&E/Nissl/TUNEL staining suggested that Res could alleviate neuronal lesions. Moreover, Res inhibited the expressions of pro-inflammatory factors (IL-6, TNF-α) and chemokines (CCL3, CXCL10, MCP-1), but increased the expressions of anti-inflammatory factors (IL-4, IL-10) and neurotrophic factor (TGF-ß, NGF and GDNF) in brain. In vitro cultured microglia cells, Res could suppress M1 microglia polarization and activate M2 microglia polarization. Co-culture of PRV-infected microglia with neuron cells by transwell system indicated that Res alleviated inflammatory response and neuronal apoptosis. CONCLUSION: This study provided evidence that Res could protect mice from PRV-induced encephalitis through regulation of microglia polarization and neuronal apoptosis suggesting the potential for treatment of viral encephalitis.

Salvia miltiorrhiza polysaccharide and its related metabolite 5-methoxyindole-3-carboxaldehyde ameliorate experimental colitis by regulating Nrf2/Keap1 signaling pathway.

The roots of Salvia miltiorrhiza have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this plant are usually discarded in the production of roots preparation. To make better use of these plant resources, the polysaccharide isolated from the aerial part of S. miltiorrhiza was investigated for its potential protection against intestinal diseases. A pectic polysaccharide (SMAP-1) was isolated and characterized being composed of homogalacturonan as the main chain and rhamnogalacturonan type I as ramified region, with side chains including arabinans and possible arabinogalactan type I and II. SMAP-1 exhibited robust protective effects against dextran sodium sulfate (DSS)-induced colitis and restored colitis symptoms, colonic inflammation, and barrier functions. Anti-oxidative effects were also observed by up-regulating Nrf2/Keap1 signaling pathway. Additionally, the level of serum 5-methoxyindole-3-carboxaldehyde (5-MC) was restored by SMAP-1 identified in metabolomic analysis, being correlated with the aforementioned effects. Protection against oxidative stress on intestinal porcine enterocyte cells (IPEC-J2) by 5-MC was observed through the activation of Nrf2/Keap1 system, as also shown by SMAP-1. In conclusion, SMAP-1 could be a promising candidate for colitis prevention, and 5-MC could be the signal metabolite of SMAP-1 in protecting against oxidative stress in the intestine.

Brevicidine acts as an effective sensitizer of outer membrane-impermeable conventional antibiotics for Acinetobacter baumannii treatment.

The antibiotic resistance of Acinetobacter baumannii poses a significant threat to global public health, especially those strains that are resistant to carbapenems. Therefore, novel strategies are desperately needed for the treatment of infections caused by antibiotic-resistant A. baumannii. In this study, we report that brevicidine, a bacterial non-ribosomally produced cyclic lipopeptide, shows synergistic effects with multiple outer membrane-impermeable conventional antibiotics against A. baumannii. In particular, brevicidine, at a concentration of 1 µM, lowered the minimum inhibitory concentration of erythromycin, azithromycin, and rifampicin against A. baumannii strains by 32-128-fold. Furthermore, mechanistic studies were performed by employing erythromycin as an example of an outer membrane-impermeable conventional antibiotic, which showed the best synergistic effects with brevicidine against the tested A. baumannii strains in the present study. The results demonstrate that brevicidine disrupted the outer membrane of A. baumannii at a concentration range of 0.125-4 µM in a dose-dependent manner. This capacity of brevicidine could help the tested outer membrane-impermeable antibiotics enter A. baumannii cells and thereafter exert their antimicrobial activity. In addition, the results show that brevicidine-erythromycin combination exerted strong A. baumannii killing capacity by the enhanced inhibition of adenosine triphosphate biosynthesis and accumulation of reactive oxygen species, which are the main mechanisms causing the death of bacteria. Interestingly, brevicidine and erythromycin combination showed good therapeutic effects on A. baumannii-induced mouse peritonitis-sepsis models. These findings demonstrate that brevicidine is a promising sensitizer candidate of outer membrane-impermeable conventional antibiotics for treating A. baumannii infections in the post-antibiotic age.