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

Polyvinyl pyrrolidone/carboxymethyl chitosan hydrogel loaded with Paris polyphylla var. yunnanensis extracellular vesicles promotes wound healing

Wound healing presents a persistent challenge, particularly in enhancing tissue regeneration and mitigating inflammation. Conventional wound dressings often fall short in providing adequate protection against microbial infections and do not fully support the regenerative processes necessary for effective healing. In this study, extracellular vesicles (PPEVs) were successfully isolated from Paris polyphylla var. yunnanensis, with an average particle size of 156.8 ± 13.15 nm and a zeta potential of -15 ± 2.54 mV. Transmission electron microscopy (TEM) images confirmed that the PPEVs exhibited an irregular spherical shape, characteristics of extracellular vesicles. PPEVs demonstrated significant anti-inflammatory properties, reducing the expression of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α by >1.5 times relative to the model group. Additionally, PPEVs promoted the expression of epidermal growth factor and collagen mRNA, exhibiting potent reactive oxygen species (ROS) scavenging activity, with 50 % reduction in ROS levels in the high-concentration group compared to the positive control. To facilitate the controlled delivery of PPEVs and promote wound healing, a composite hydrogel was developed by incorporating polyvinylpyrrolidone (PVP) and carboxymethyl chitosan (CMC) through physical crosslinking. The hydrogel exhibited high porosity (43.6 ± 7.2 %) and remarkable swelling capacity (445.4 ± 38.3 %), with a drug release of 61.3 ± 11.8 % within 6 h. Rheological analysis revealed that the hydrogel exhibited pseudoplastic behavior and elastic characteristics, with good thermal stability. In vivo studies demonstrated that the wound healing rate in the PPEVs@PVP/CMC hydrogel group on day 7 (82.17 ± 5.44 %) was significantly higher than that of the control group (58.5 ± 12.15 %). On day 14, the wounds in the PPEVs@PVP/CMC group were nearly completely healed, with a healing rate of 99.66 ± 0.42 %, significantly surpassing the control group (95.85 ± 0.90 %). Therefore, the PPEVs@PVP/CMC hydrogel can serve as a safe and efficient wound dressing to regulate the inflammatory response and accelerate wound healing in mice. This finding suggests that utilizing the PPEVs@PVP/CMC hydrogel may be a promising strategy for wound healing.

Erythropoietin-Stimulated Macrophage-Derived Extracellular Vesicles in Chitosan Hydrogel Rescue BMSCs Fate by Targeting EGFR to Alleviate Inflammatory Bone Loss in Periodontitis

Loss of periodontal tissue due to persistent inflammation in periodontitis is a major cause of tooth loss in adults. Overcoming osteogenic inhibition in the inflammatory periodontal environment and restoring the regenerative capacity of endogenous bone marrow mesenchymal stem cells (BMSCs) remain critical challenges in current treatment approaches. Macrophage-derived extracellular vesicles (EVs) are key regulators of osteogenesis in recipient cells, yet the role of erythropoietin (EPO) in modifying macrophages and the function of their EVs in bone regeneration remain unclear. In this study, EVs from EPO-stimulated macrophages (EPO-EVs) are isolated, and they are encapsulated in a chitosan/β-sodium glycerophosphate/gelatin (CS/β-GP/gelatin) hydrogel to create a controlled-release EVs delivery system for localized periodontal environment. EPO-EVs restore the osteogenic function of mouse BMSCs (mBMSCs) and mitigate inflammatory bone loss in a periodontitis mouse model. Mechanistically, miR-5107-5p, significantly enriched in EPO-EVs, is delivered to mBMSCs, where it suppresses epidermal growth factor receptor (EGFR) expression and alleviates EGFR's inhibitory effect on RhoA. This process counteracts osteogenic inhibition in inflammatory settings through the EGFR/RhoA axis. Overall, EVs from EPO pretreated macrophages restore the osteogenic capacity of mBMSCs under inflammation by inhibiting EGFR expression, providing new insight into therapeutic mechanisms and offering a promising approach for future periodontitis treatment.

Circulating plasma derived exosomes from systemic lupus erythematosus aggravate lupus nephritis through miR-122-5p/FOXO3-mediated macrophage activation

Systemic lupus erythematosus (SLE) is a chronic and systemic autoimmune disease characterized by dysregulation in both innate and adaptive immunity. Polarization of macrophages into M1/M2 macrophages affects the development of lupus. Exosomes-miRNA plays a crucial role in disease progression. This study aims to explore the mechanism of circulating exosomes participating in the pathogenesis of SLE and seek new therapeutic targets. Plasma derived-exosomes from SLE patients accelerated the disease progression and polarization of macrophages of the kidney in MRL/lpr mice. Exosomes were taken up by macrophages and stimulated macrophage polarization in vitro. MiRNA-sequence analysis revealed that plasma-derived exosomal miR-151a-5p, miR-1180a-5p, miR-1246 and miR-122-5p were abnormal. Of them, the expression of miR-122-5p was significantly upregulated in SLE exosomes, and positively correlated with systemic lupus erythematosus disease activity index (SLEDAI) and the dsDNA levels. Compared with SLE exosomes, inhibition of circulating exosomal miR-122-5p from SLE patients relieved lupus clinical aspects and polarization of macrophage. SLE exosomal miR-122-5p motivated M1 macrophage polarization by targeting FOXO3/NF-κB signaling pathway. Based on these findings, we conclude that SLE exosomal miR-122-5p can promote M1 macrophage polarization via targeting FOXO3/NF-κB signaling pathway and participate in pathogenesis of SLE. Collectively, plasma-derived exosomal miR-122-5p is a promising and effective target for treating SLE.

miR-331-depleted exosomes derived from injured endometrial epithelial cells promote macrophage activation during endometritis

Exosomes are natural carriers of biological macromolecules that are involved in the pathogenesis of a wide variety of inflammatory diseases. The purpose of this study was to investigate the role of exosomes derived from injured endometrial epithelial cells (EECs) in the development of endometritis. We isolated exosomes derived from LPS-injured EECs and identified these exosomes as proinflammatory mediators that can be internalized by macrophages and thus induce proinflammatory macrophage activation. We further found that miR-331 expression was sharply downregulated in exosomes derived from LPS-injured EECs and that macrophages treated with these exosomes also presented a lower level of miR-331. Importantly, the pathogenic role of exosomal miR-331 in promoting endometrial inflammation was revealed by the ability of adoptively transferred EECs-derived exosomes to cause macrophage activation, and this was reversed by miR-331 overexpression. Mechanistically, overexpression of miR-331 in macrophages mitigated NF-κB p65 phosphorylation by inhibiting the Notch1/IKKα pathway, which in turn curbed macrophage activation. In vivo assays further unveiled that miR-331 expression is negatively correlated with proinflammatory macrophage activation and that miR-331 upregulation markedly slowed disease progression in mice with endometritis. The exosome/miR-331/Notch1 axis plays a critical pathological role in endometrial inflammation, representing a new therapeutic target for endometritis.

Lactobacillus rhamnosus GG-derived extracellular vesicles promote wound healing via miR-21-5p-mediated re-epithelization and angiogenesis

Extracellular vesicles (EVs), especially those derived from stem cells, have emerged as a novel treatment for promoting wound healing in regenerative medicine. However, the clinical application of mammalian cells-derived EVs is hindered by their high cost and low yields. Inspired by the ability of EVs to mediate interkingdom communication, we explored the therapeutic potential of EVs released by the probiotic strain Lactobacillus rhamnosus GG (LGG) in skin wound healing and elucidated the underlying mechanism involved. Using full-thickness skin wound-healing mouse models, we found that LGG-EVs accelerated wound healing procedures, including increased re-epithelialization and promoted angiogenesis. Using in vitro experiments, we further demonstrated that LGG-EVs boosted the proliferation and migration capacities of both epithelial and endothelial cells, as well as promoted endothelial tube formation. miRNA profiling analysis revealed that miR-21-5p was highly enriched in LGG-EVs and LGG-EV treatment significantly increased miR-21-5p level in recipient cells. Mechanically, LGG-EVs induced regulatory effects via miR-21-5p mediated metabolic signaling rewiring. Our results suggest that EVs derived from LGG could serve as a promising candidate for accelerating wound healing and possibly for treating chronic and impaired healing conditions.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

Epigallocatechin-3-gallate derived polymer coated Prussian blue for synergistic ROS elimination and antibacterial therapy

Reactive oxygen species (ROS) play a vital role in wound healing process by fighting against invaded bacteria. However, excess ROS at the wound sites lead to oxidative stress that can trigger deleterious effects, causing cell death, tissue damage and chronic inflammation. Therefore, we fabricated a core-shell structured nanomedicine with antibacterial and antioxidant properties via a facile and green strategy. Specifically, Prussian blue (PB) nanozyme was fabricated and followed by coating a layer of epigallocatechin-3-gallate (EGCG)-derived polymer via polyphenolic condensation reaction and self-assembly process, resulting in PB@EGCG. The introduction of PB core endowed EGCG-based polyphenol nanoparticles with excellent NIR-triggered photothermal properties. Besides, owing to multiple enzyme-mimic activity of PB and potent antioxidant capacity of EGCG-derived polymer, PB@EGCG exhibited a remarkable ROS-scavenging ability, mitigated intracellular ROS level and protected cells from oxidative damage. Under NIR irradiation (808 nm, 1.5 W/cm2), PB@EGCG (50 µg/mL) exerted synergistic EGCG-derived polymer-photothermal antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). In vivo therapeutic effect was evaluated using a S. aureus-infected rat model indicated PB@EGCG with a prominent bactericidal ability could modulate the inflammatory microenvironment and accelerate wound healing. Overall, this dual-functional nanomedicine provides a promising strategy for efficient antibacterial therapy.

Network Pharmacology Study on Herb Pair Bletilla striata-Galla chinensis in the Treatment of Chronic Skin Ulcers

BACKGROUND

Herb pair Bletilla striata-Galla chinensis (BS-GC) is a classic combination of topical traditional Chinese medicine formulae in the treatment of chronic skin ulcers (CSUs).

OBJECTIVE

The aim of this study is to explore the effective active ingredients of BS-GC, as well as the core targets and signal transduction pathways of its action on CSUs.

METHODS

The ingredients of BS-GC were obtained from TCMSP and HERB databases. The targets of all active ingredients were retrieved from the SwissTargetPrediction database. The targets of CSUs were obtained from OMIM, GeneCards, Drugbank, and DisGeNET databases. A drug-disease target protein-protein interaction (PPI) network was constructed to select the most core targets, and an herb-ingredient-target network was built by utilizing Cytoscape 3.7.2. Furthermore, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes database (KEGG) analysis and verified the results of network pharmacology through molecular docking.

RESULTS

A total of 40 active ingredients from the herb pair BS-GC were initially screened, and a total of 528 targets were retrieved. Meanwhile, the total number of CSU targets was 1032. Then, the number of common targets between BS-GC and CSUs was 107. The 13 core targets of herb pair BS-GC with CSUs were filtered out according to the PPI network, including AKT1, TNF, EGFR, BCL2, HIF1A, MMP-9, etc. The 5 main core active ingredients were 1-(4-Hydroxybenzyl)-2-methoxy-9,10-dihydrophenanthrene-4,7-diol, 1-(4- Hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene-2,7-diol, physcion, dihydromyricetin, and myricetin. The main biological processes were inflammation, oxidative stress, and immune response, involving the AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, NF-κB signaling pathway, and calcium signaling pathway. Molecular docking results showed good binding activity between the 5 main core active ingredients and 13 core targets.

CONCLUSION

This study predicted the core targets and signal transduction pathways in the treatment of CSUs to provide a reference for further molecular mechanism research.