"Find-eat" strategy targeting endothelial cells via receptor functionalized apoptotic body nanovesicle

Apoptotic Bodies Restore NAD and Mitochondrial Homeostasis in Fibroblasts

Fibrotic skin diseases are characterized by excessive fibroblast proliferation and pathological extracellular matrix deposition. As a pivotal coenzyme in cellular energetics, NAD homeostasis perturbation is implicated in fibrosis. Multiple studies have demonstrated the therapeutic potential of mesenchymal stem cells (MSCs) against cutaneous fibrosis, while the specific mechanism remains elusive. Herein, this work finds that although almost all MSCs undergo in situ apoptosis within 24 h post-subcutaneous administration, MSC-derived apoptotic bodies (ABs) mediated potent anti-fibrotic effects. Mechanistically, ABs can restore NAD and mitochondrial homeostasis through NAMPT transfer, FOXO1 deacetylation enhancement, and PINK1/PARKIN-dependent mitophagy activation. To achieve penetration into the hard matrix of fibrotic skin, permeable apoptotic bodies (pABs) are constructed via metabolic glycoengineering and copper-free click chemistry techniques. In both keloid xenograft and scleroderma murine models, pABs can significantly penetrate collagen matrix and reduce skin fibrosis. In summary, this research establishes a highly promising strategy for reversing skin fibrosis with hard fibrotic matrix.

Meningeal lymphatic drainage: novel insights into central nervous system disease

In recent years, increasing evidence has suggested that meningeal lymphatic drainage plays a significant role in central nervous system (CNS) diseases. Studies have indicated that CNS diseases and conditions associated with meningeal lymphatic drainage dysfunction include neurodegenerative diseases, stroke, infections, traumatic brain injury, tumors, functional cranial disorders, and hydrocephalus. However, the understanding of the regulatory and damage mechanisms of meningeal lymphatics under physiological and pathological conditions is currently limited. Given the importance of a profound understanding of the interplay between meningeal lymphatic drainage and CNS diseases, this review covers seven key aspects: the development and structure of meningeal lymphatic vessels, methods for observing meningeal lymphatics, the function of meningeal lymphatics, the molecular mechanisms of meningeal lymphatic injury, the relationships between meningeal lymphatic vessels and CNS diseases, potential regulatory mechanisms of meningeal lymphatics, and conclusions and outstanding questions. We will explore the relationship between the development, structure, and function of meningeal lymphatics, review current methods for observing meningeal lymphatic vessels in both animal models and humans, and identify unresolved key points in meningeal lymphatic research. The aim of this review is to provide new directions for future research and therapeutic strategies targeting meningeal lymphatics by critically analyzing recent advancements in the field, identifying gaps in current knowledge, and proposing innovative approaches to address these gaps.

Androgen receptor inhibitor ameliorates pulmonary arterial hypertension by enhancing the apoptosis level through suppressing the Notch3/Hes5 pathway

Background

Pulmonary arterial hypertension (PAH) exhibits significant gender differences in prognosis, with male patients typically showing worse outcomes than females. These disparities may stem from differences in androgen receptor expression and activity. Clinical studies suggest that the androgen receptor plays a crucial role in the pathophysiology of PAH, influencing disease progression and treatment response. Despite the lack of targeted therapies for PAH, these findings have spurred investigations into the potential therapeutic role of androgen receptors. This study explores the role of androgen receptors in PAH and evaluates their therapeutic potential.

Methods

PAH was induced in rats via intraperitoneal injection of monocrotaline (MCT). Following model establishment, Enzalutamide was administered every 3 days at 10 mg/kg once for a total of 7 times (21 days). A mouse model of PAH was developed by subcutaneously injecting SU5416 and exposing the mice to hypoxia. Androgen receptor knockout (AR-/-) mice were also utilized to investigate the role of androgen receptors in disease progression. Key indicators were compared across groups. The in vivo mechanisms through which androgen receptors influence PAH were examined in both rat and mouse models. Additionally, mouse pulmonary artery endothelial cells (PAECs) were cultured under hypoxic conditions to create an in vitro model of PAH, facilitating further investigation into the role of androgen receptors in disease pathogenesis.

Results

Compared to the normal group, the model group exhibited significantly increased androgen receptor expression in rats, mice, and mPAECs. This was accompanied by pronounced pulmonary artery wall thickening, right ventricular hypertrophy, pulmonary fibrosis, elevated pulmonary artery pressure, and a reduced level of apoptosis both in vivo and in vitro. Furthermore, activation of the Notch3/Hes5 signaling pathway was observed. However, treatment with androgen receptor inhibitors or gene knockout significantly ameliorated these pathological changes. Apoptosis levels increased both in vivo and in vitro, and the activation of the Notch3/Hes5 signaling pathway was effectively inhibited.

Conclusion

Our findings suggest that in both animal models and the hypoxic mPAECs, inhibition of androgen receptor expression leads to increased apoptosis via suppression of the Notch3/Hes5 signaling pathway. This mechanism likely contributes to the therapeutic effects observed, providing insights for potential treatment strategies targeting androgen receptors in pulmonary arterial hypertension.

Boosting mRNA-Engineered Monocytes via Prodrug-Like Microspheres for Bone Microenvironment Multi-Phase Remodeling

Monocytes, as progenitors of macrophages and osteoclasts, play critical roles in various stages of bone repair, necessitating phase-specific regulatory mechanisms. Here, icariin (ICA) prodrug-like microspheres (ICA@GM) are developed, as lipid nanoparticle (LNP) transfection boosters, to construct mRNA-engineered monocytes for remodeling the bone microenvironment across multiple stages, including the acute inflammatory and repair phases. Initially, ICA@GM is prepared from ICA-conjugated gelatin methacryloyl via a microfluidics system. Then, monocyte-targeting IL-4 mRNA-LNPs are then prepared and integrated into injectable microspheres (mRNA-ICA@GM) via electrostatic and hydrogen bond interactions. After bone-defect injection, LNPs are controlled released from mRNA-ICA@GM within 3 days, rapidly transfecting monocytes for monocyte IL-4 mRNA-engineering, which effectively suppressed acute inflammatory responses via polarization programming and paracrine signaling. Afterwards, ICA is sustainably released as well via cleavable boronate esters across multiple stages, cooperatively boosting the mRNA-engineered monocytes to inhibit coenocytic fusion and osteoclastic function. Both in vitro and in vivo data indicated that mRNA-ICA@GM can not only reverse the inflammatory environment but also suppress monocyte-derived osteoclast formation to accelerate bone repair. In summary, mRNA-engineered monocytes and ICA prodrug-like microspheres are combined to achieve long-lasting multi-stage bone microenvironment regulation, offering a promising repair strategy.

Role of Triple-Negative Breast Cancer-Derived Extracellular Vesicles in Metastasis: Implications for Therapeutics and Biomarker Development

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer with a poor prognosis and high mortality. The chemotherapeutic regimen remains the predominant treatment modality for TNBC in current clinical practice. However, chemotherapy resistance significantly complicates the development of an effective treatment regimen. Furthermore, the immunosuppressive microenvironment of TNBC contributes to enhanced tumour aggressiveness. Consequently, understanding its mechanisms of progression and finding effective therapeutic interventions is crucial. Recent evidence has identified extracellular vesicles (EVs) as key mediators of cell-to-cell communication in TNBC progression and immune regulation. In view of the remarkable ability of EVs to transfer active molecules, such as proteins and nucleic acids, from parental to recipient cells, they are regarded as a promising biomarker and novel drug delivery system. In this review, we provide an overview of how EVs derived from TNBC cells and tumour microenvironment cells play a role in regulating tumour progression. We also discuss the potential of EVs for immune regulation and their application as novel therapeutic strategies and tumour markers in TNBC. The knowledge gained from studying EV-mediated communication in TNBC could lead to the development of targeted therapies and improve patient outcomes.

The application and development prospects of extracellular vesicles in oral administration

Extracellular vesicles (EVs) are nanoscale phospholipid-based particles secreted by cells and are essential mediators responsible for intercellular signal communication. The rapid development of EV nanotechnology has brought unprecedented opportunities for nanomedicine. Among various administration methods, oral administration is the most convenient and simplest. However, most drugs (peptides, small molecule drugs, nucleic acids, and therapeutic proteins) greatly reduce their oral bioavailability due to the harsh gastrointestinal environment. Notably, some EVs have been shown to cross biological barriers, including the gastrointestinal tract. The distinctive biological properties of EVs make them a promising natural carrier for oral drug delivery. This review introduces the characteristics of EVs, covering their classification, production methods, and therapeutic efficacy in oral administration. Additionally, we explore the potential roles of EVs in disease prevention and treatment, as well as their future prospects in pharmaceutical applications. This comprehensive overview aims to provide insights into the application of EVs in oral drug delivery, highlighting their advantages, current progress, and the challenges that need to be overcome for successful clinical translation.

Slide-Ring Structured Stress-Electric Coupling Hydrogel Microspheres for Low-Loss Transduction Between Tissues

High transductive loss at tissue injury sites impedes repair. The high dissipation characteristics in the electromechanical conversion of piezoelectric biomaterials pose a challenge. Therefore, supramolecular engineering and microfluidic technology is utilized to introduce slide-ring polyrotaxane and conductive polypyrrole to construct stress-electric coupling hydrogel microspheres. The molecular slippage mechanism of slide-ring structure stores and releases mechanical energy, reducing mechanical loss, the piezoelectric barium titanate enables stress-electricity conversion, and conjugated π-electron movement in conductive network improves the internal electron transfer efficiency of microspheres, thereby reducing the loss in stress-electricity conversion for the first time. Compared to traditional piezoelectric hydrogel microspheres, the stress-electric coupling efficiency of low-dissipation microspheres increased by 2.3 times, and the energy dissipation decreased to 43%. At cellular level, electrical signals generated by the microspheres triggered Ca2+ influx into stem cells and upregulated the cAMP signaling pathways, promoting chondrogenic differentiation. Enhanced electrical signals induced macrophage polarization to the M2 phenotype, reshaping inflammation and promoting tissue repair. In vivo, the low-dissipation microspheres restored low-loss transduction between tissues, alleviated cartilage damage, improved behavioral outcomes, and promoted the treatment of osteoarthritis in rats. Therefore, this study proposes a new strategy for restoring low-loss transduction between tissues, particularly in mechanically sensitive tissues.

In Situ Proefferocytosis Microspheres as Macrophage Polarity Converters Accelerate Osteoarthritis Treatment

Efferocytosis in macrophages typically engages an anti-inflammatory positive feedback regulatory mechanism. In osteoarthritis (OA), characterized by imbalanced inflammatory homeostasis, the proinflammatory state of macrophages in the immune microenvironment can be reversed through enhanced efferocytosis. This study develops an in situ proefferocytosis hydrogel microsphere (macrophage polarity converter, H-C@IL) for OA treatment. Immunoliposomes (IL), CD16/32 antibody-modified clodronate liposomes, are initially prepared using the Re-emulsion method. Then, the IL is loaded into CCL19-modified HAMA microspheres through microfluidic technology. In vitro, H-C@IL can specifically recruit M0 and M1 macrophages via CCL19, induce apoptosis in M1 macrophages through secondary targeting with IL, and provide "Find/Eat-me" signals to enhance in situ efferocytosis. Additionally, it promotes macrophage polarization toward the M2 phenotype. In vivo, behavioral, imaging, and histological analyses demonstrate that H-C@IL effectively facilitates macrophage polarization toward M2, inhibits inflammation, and promotes cartilage regeneration. Mechanistically, H-C@IL enhances efferocytosis by activating proteins such as PROS1 and TIMD4 in M0 macrophages. Concurrently, signaling pathways, including PQLC2-Arg-Rac1 and Pbx1/IL-10, are activated to drive the polarization of macrophages from M0 to M2. In summary, H-C@IL promotes M0 macrophage efferocytosis in situ, facilitates macrophage polarization toward M2, restores inflammatory homeostasis, and promotes cartilage regeneration, offering a comprehensive treatment strategy for OA.

Biosynthesis of Lysosomally Escaped Apoptotic Bodies Inhibits Inflammasome Synthesis in Macrophages

Hyperglycemia and bacterial colonization in diabetic wounds aberrantly activate Nod-like receptor protein 3 (NLRP3) in macrophages, resulting in extensive inflammatory infiltration and impaired wound healing. Targeted suppression of the NLRP3 inflammasome shows promise in reducing macrophage inflammatory disruptions. However, challenges such as drug off-target effects and degradation via lysosomal capture remain during treatment. In this study, engineered apoptotic bodies (BHB-dABs) derived from adipose stem cells loaded with β-hydroxybutyric acid (BHB) were synthesized via biosynthesis. These vesicles target M1-type macrophages, which highly express the folic acid receptor in the inflammatory microenvironment, and facilitate lysosomal escape through 1,2-distearoyl-sn-propyltriyl-3-phosphatidylethanolamine-polyethylene glycol functionalization, which may enhance the efficacy of NLRP3 inhibition for managing diabetic wounds. In vitro studies demonstrated the biocompatibility of BHB-dABs, their selective targeting of M1-type macrophages, and their ability to release BHB within the inflammatory microenvironment via folic acid and folic acid receptor signaling. These nanovesicles exhibited lysosomal escape, anti-inflammatory, mitochondrial protection, and endothelial cell vascularization properties. In vivo experiments demonstrated that BHB-dABs enhance the recovery of diabetic wound inflammation and angiogenesis, accelerating wound healing. These functionalized apoptotic bodies efficiently deliver NLRP3 inflammasome inhibitors using a dual strategy of targeting macrophages and promoting lysosomal escape. This approach represents a novel therapeutic strategy for effectively treating chronic diabetic wounds.

Engineered Nanoparticles for Theranostic Applications in Kidney Repair

Kidney diseases are characterized by their intricate nature and complexity, posing significant challenges in their treatment and diagnosis. Nanoparticles (NPs), which can be further classified as synthetic and biomimetic NPs, have emerged as promising candidates for treating various diseases. In recent years, the development of engineered nanotherapeutics has focused on targeting damaged tissues and serving as drug delivery vehicles. Additionally, these NPs have shown superior sensitivity and specificity in diagnosis and imaging, thus providing valuable insights for the early detection of diseases. This review aims to focus on the application of engineered synthetic and biomimetic NPs in kidney diseases in the aspects of treatment, diagnosis, and imaging. Notably, the current perspectives and challenges are evaluated, which provide inspiration for future research directions, and encourage the clinical application of NPs in this field.

Drug-phospholipid conjugate nano-assembly for drug delivery

Phospholipid-based liposomes are among the most successful nanodrug delivery systems in clinical use. However, these conventional liposomes present significant challenges including low drug-loading capacity and issues with drug leakage. Drug-phospholipid conjugates (DPCs) and their assemblies offer a promising strategy for addressing these limitations. In this review, we summarize recent advances in the design, synthesis, and application of DPCs for drug delivery. We begin by discussing the chemical backbone structures and various design strategies such as phosphate head embedding and mono-/bis-embedding in the sn-1/sn-2 positions. Furthermore, we highlight stimulus-responsive designs of DPCs and their applications in treating diseases such as cancer, inflammation, and malaria. Lastly, we explore future directions for DPCs development and their potential applications in drug delivery.

Intelligent Hydrogel-Assisted Hepatocellular Carcinoma Therapy

Given the high malignancy of liver cancer and the liver's unique role in immune and metabolic regulation, current treatments have limited efficacy, resulting in a poor prognosis. Hydrogels, soft 3-dimensional network materials comprising numerous hydrophilic monomers, have considerable potential as intelligent drug delivery systems for liver cancer treatment. The advantages of hydrogels include their versatile delivery modalities, precision targeting, intelligent stimulus response, controlled drug release, high drug loading capacity, excellent slow-release capabilities, and substantial potential as carriers of bioactive molecules. This review presents an in-depth examination of hydrogel-assisted advanced therapies for hepatocellular carcinoma, encompassing small-molecule drug therapy, immunotherapy, gene therapy, and the utilization of other biologics. Furthermore, it examines the integration of hydrogels with conventional liver cancer therapies, including radiation, interventional therapy, and ultrasound. This review provides a comprehensive overview of the numerous advantages of hydrogels and their potential to enhance therapeutic efficacy, targeting, and drug delivery safety. In conclusion, this review addresses the clinical implementation of hydrogels in liver cancer therapy and future challenges and design principles for hydrogel-based systems, and proposes novel research directions and strategies.

Engineering strategies for apoptotic bodies

Extracellular vesicles (EVs) are lipid bilayer vesicles containing proteins, lipids, nucleic acids, and metabolites secreted by cells under various physiological and pathological conditions that mediate intercellular communication. The main types of EVs include exosomes, microvesicles, and apoptotic bodies (ABs). ABs are vesicles released during the terminal stages of cellular apoptosis, enriched with diverse biological entities and characterized by distinct morphological features. As a result, ABs possess great potential in fields like disease diagnosis, immunotherapy, regenerative therapy, and drug delivery due to their specificity, targeting capacity, and biocompatibility. However, their therapeutic efficacy is notably heterogeneous, and an overdose can lead to side effects such as accumulation in the liver, spleen, lungs, and gastrointestinal system. Through bioengineering, the properties of ABs can be optimized to enhance drug-loading efficiency, targeting precision, and multifunctionality for clinical implementations. This review focuses on strategies such as transfection, sonication, electroporation, surface engineering, and integration with biomaterials to enable ABs to load cargoes and enhance targeting, providing insights into the engineering of ABs.

Picein alleviates oxidative stress and promotes bone regeneration in osteoporotic bone defect by inhibiting ferroptosis via Nrf2/HO-1/GPX4 pathway

Osteoporosis (OP) can result in slower bone regeneration than the normal condition due to abnormal oxidative stress and high levels of reactive oxygen species (ROS), a condition detrimental for bone formation, making the OP-related bone healing a significant clinical challenge. As the osteogenic differentiation ability of bone marrow mesenchymal stem cells (BMSCs) is closely related to bone regeneration; currently, this study assessed the effects of Picein on BMSCs in vitro and bone regeneration in osteoporotic bone defect in vivo. Cell viability was determined by CCK-8 assay. The production of (ROS), malonaldehyde, superoxide dismutase activities, and glutathione was evaluated by using commercially available kits, and a flow cytometry analysis was adopted to detect macrophage polarization. Osteogenic capacity of BMSCs was evaluated by alkaline phosphatase (ALP) activity, ALP staining, and Alizarin red S staining. The expression of osteogenic-related proteins (OPN, Runx-2, OCN) and osteogenic-related genes (ALP, BMP-4, COL-1, and Osterix) were evaluated by Western blotting and real-time PCR (RT-PCR). In addition, proliferation, migration ability, and angiogenic capacity of human umbilical vein endothelial cells (HUVECs) were evaluated by EdU staining, scratch test, transwell assay, and tube formation assay, respectively. Angiogenic-related genes (VEGF, vWF, CD31) were also evaluated by RT-PCR. Results showed that Picein alleviated erastin-induced oxidative stress, enhanced osteogenic differentiation capacity of BMSCs, angiogenesis of HUVECs, and protects cells against ferroptosis through Nrf2/HO-1/GPX4 axis. Moreover, Picein regulate immune microenvironment by promoting the polarization of M2 macrophages in vitro. In addition, Picein also reduce the inflammation levels and promotes bone regeneration in osteoporotic bone defect in OP rat models in vivo. Altogether, these results suggested that Picein can promote bone regeneration and alleviate oxidative stress via Nrf2/HO-1/GPX4 pathway, offering Picein as a novel antioxidant agent for treating osteoporotic bone defect.

A Genetically Engineered "Reinforced Concrete" Scaffold Regulates the N2 Neutrophil Innate Immune Cascade to Repair Bone Defects

The innate immune response is crucial to inflammation, but how neutrophils and macrophages act in bone repair and tissue engineering treatment strategies await clarification. In this study, it is found that N2 neutrophils release stronger "eat me" signals to induce macrophage phagocytosis and polarize into the M2 anti-inflammatory phenotype. Guided by this biological mechanism, a mesoporous bioactive glass scaffold (MBG) is filled with hyaluronic acid methacryloyl (HAMA) hydrogel loaded with Transforming growth factor-β1 (TGFβ1) adenovirus (Ad@H), constructing a genetically engineered composite scaffold (Ad@H/M). The scaffold not only has good hydrophilicity and biocompatibility, but also provides mechanical stress support for bone repair. Adenovirus infection quickly induces N2 neutrophils, upregulating NF-κB and MAPK signaling pathways through Toll-like receptor 4 (TLR4) to promote the inflammatory response and macrophage phagocytosis. Macrophages perform phagocytosis and polarize towards the M2 phenotype, mediating the inflammatory response by inhibiting the PI3K-AKT-NF-κB pathway, maintaining homeostasis of the osteogenic microenvironment. The role of the Ad@H/M scaffold in regulating early inflammation and promoting long-term bone regeneration is further validated in vivo. In brief, this study focuses on the cascade of reactions between neutrophils and macrophage subtypes, and reports a composite scaffold that coordinates the innate immune response to promote bone repair.

Activating Macrophage Continual Efferocytosis via Microenvironment Biomimetic Short Fibers for Reversing Inflammation in Bone Repair

Efferocytosis-mediated inflammatory reversal plays a crucial role in bone repairing process. However, in refractory bone defects, the macrophage continual efferocytosis may be suppressed due to the disrupted microenvironment homeostasis, particularly the loss of apoptotic signals and overactivation of intracellular oxidative stress. In this study, a polydopamine-coated short fiber matrix containing biomimetic "apoptotic signals" to reconstruct the microenvironment and reactivate macrophage continual efferocytosis for inflammatory reversal and bone defect repair is presented. The "apoptotic signals" (AM/CeO2) are prepared using CeO2 nanoenzymes with apoptotic neutrophil membrane coating for macrophage recognition and oxidative stress regulation. Additionally, a short fiber "biomimetic matrix" is utilized for loading AM/CeO2 signals via abundant adhesion sites involving π-π stacking and hydrogen bonding interactions. Ultimately, the implantable apoptosis-mimetic nanoenzyme/short-fiber matrixes (PFS@AM/CeO2), integrating apoptotic signals and biomimetic matrixes, are constructed to facilitate inflammatory reversal and reestablish the pro-efferocytosis microenvironment. In vitro and in vivo data indicate that the microenvironment biomimetic short fibers can activate macrophage continual efferocytosis, leading to the suppression of overactivated inflammation. The enhanced repair of rat femoral defect further demonstrates the osteogenic potential of the pro-efferocytosis strategy. It is believed that the regulation of macrophage efferocytosis through microenvironment biomimetic materials can provide a new perspective for tissue repair.

Hybrid Hydrogels for Immunoregulation and Proangiogenesis through Mild Heat Stimulation to Accelerate Whole-Process Diabetic Wound Healing

Intense and persistent oxidative stress, excessive inflammation, and impaired angiogenesis severely hinder diabetic wound healing. Bioactive hydrogel dressings with immunoregulatory and proangiogenic properties have great promise in treating diabetic wounds. However, the therapeutic effects of dressings always depend on drugs with side effects, expensive cytokines, and cell therapies. Herein, a novel dynamic borate-bonds crosslinked hybrid multifunctional hydrogel dressings with photothermal properties are developed to regulate the microenvironment of diabetic wound sites and accelerate the whole process of its healing without additional medication. The hydrogel is composed of phenylboronic acid-modified chitosan and hyaluronic acid (HA) crosslinked by tannic acid (TA) through borate bonds and Prussian blue nanoparticles (PBNPs) with photothermal response characteristics are embedded in the polymer networks. The results indicate hydrogels show inherent broad-spectrum antioxidative activities through the integrated interaction of borate bonds, TA, and PBNPs. Meanwhile, combined with the regulation of macrophage phenotype by HA, the inflammatory microenvironment of diabetic wounds is transformed. Moreover, the angiogenesis is then enhanced by the mild photothermal effect of PBNPs, followed by promoted epithelialization and collagen deposition. In summary, this hybrid hydrogel system accelerates all stages of wound repair through antioxidative stress, immunomodulation, and proangiogenesis, showing great potential applications in diabetic wound management.

Innovative Bio-based Hydrogel Microspheres Micro-Cage for Neutrophil Extracellular Traps Scavenging in Diabetic Wound Healing

Neutrophil extracellular traps (NETs) seriously impede diabetic wound healing. The disruption or scavenging of NETs using deoxyribonuclease (DNase) or cationic nanoparticles has been limited by liberating trapped bacteria, short half-life, or potential cytotoxicity. In this study, a positive correlation between the NETs level in diabetic wound exudation and the severity of wound inflammation in diabetic patients is established. Novel NETs scavenging bio-based hydrogel microspheres 'micro-cage', termed mPDA-PEI@GelMA, is engineered by integrating methylacrylyl gelatin (GelMA) hydrogel microspheres with cationic polyethyleneimine (PEI)-functionalized mesoporous polydopamine (mPDA). This unique 'micro-cage' construct is designed to non-contact scavenge of NETs between nanoparticles and the diabetic wound surface, minimizing biological toxicity and ensuring high biosafety. NETs are introduced into 'micro-cage' along with wound exudation, and cationic mPDA-PEI immobilizes them inside the 'micro-cage' through a strong binding affinity to the cfDNA web structure. The findings demonstrate that mPDA-PEI@GelMA effectively mitigates pro-inflammatory responses associated with diabetic wounds by scavenging NETs both in vivo and in vitro. This work introduces a novel nanoparticle non-contact NETs scavenging strategy to enhance diabetic wound healing processes, with potential benefits in clinical applications.

Visible-Light Cross-Linkable Multifunctional Hydrogels Loaded with Exosomes Facilitate Full-Thickness Skin Defect Wound Healing through Participating in the Entire Healing Process

The management of severe full-thickness skin defect wounds remains a challenge due to their irregular shape, uncontrollable bleeding, high risk of infection, and prolonged healing period. Herein, an all-in-one OD/GM/QCS@Exo hydrogel was prepared with catechol-modified oxidized hyaluronic acid (OD), methylacrylylated gelatin (GM), and quaternized chitosan (QCS) and loaded with adipose mesenchymal stem cell-derived exosomes (Exos). Cross-linking of the hydrogel was achieved using visible light instead of ultraviolet light irradiation, providing injectability and good biocompatibility. Notably, the incorporation of catechol groups and multicross-linked networks in the hydrogels conferred strong adhesion properties and mechanical strength against external forces such as tensile and compressive stress. Furthermore, our hydrogel exhibited antibacterial, anti-inflammatory, and antioxidant properties along with wound-healing promotion effects. Our results demonstrated that the hydrogel-mediated release of Exos significantly promotes cellular proliferation, migration, and angiogenesis, thereby accelerating skin structure reconstruction and functional recovery during the wound-healing process. Overall, the all-in-one OD/GM/QCS@Exo hydrogel provided a promising therapeutic strategy for the treatment of full-thickness skin defect wounds through actively participating in the entire process of wound healing.

Biogenerated Oxygen-Related Environmental Stressed Apoptotic Vesicle Targets Endothelial Cells

The dynamic balance between hypoxia and oxidative stress constitutes the oxygen-related microenvironment in injured tissues. Due to variability, oxygen homeostasis is usually not a therapeutic target for injured tissues. It is found that when administered intravenously, mesenchymal stem cells (MSCs) and in vitro induced apoptotic vesicles (ApoVs) exhibit similar apoptotic markers in the wound microenvironment where hypoxia and oxidative stress co-existed, but MSCs exhibited better effects in promoting angiogenesis and wound healing. The derivation pathway of ApoVs by inducing hypoxia or oxidative stress in MSCs to simulate oxygen homeostasis in injured tissues is improved. Two types of oxygen-related environmental stressed ApoVs are identified that directly target endothelial cells (ECs) for the accurate regulation of vascularization. Compared to normoxic and hypoxic ones, oxidatively stressed ApoVs (Oxi-ApoVs) showed the strongest tube formation capacity. Different oxygen-stressed ApoVs deliver similar miRNAs, which leads to the broad upregulation of EC phosphokinase activity. Finally, local delivery of Oxi-ApoVs-loaded hydrogel microspheres promotes wound healing. Oxi-ApoV-loaded microspheres achieve controlled ApoV release, targeting ECs by reducing the consumption of inflammatory cells and adapting to the proliferative phase of wound healing. Thus, the biogenerated apoptotic vesicles responding to oxygen-related environmental stress can target ECs to promote vascularization.

Alterations in CX3CL1 Levels and Its Role in Viral Pathogenesis

CX3CL1, also named fractalkine or neurotactin, is the only known member of the CX3C chemokine family that can chemoattract several immune cells. CX3CL1 exists in both membrane-anchored and soluble forms, with each mediating distinct biological activities. CX3CL1 signals are transmitted through its unique receptor, CX3CR1, primarily expressed in the microglia of the central nervous system (CNS). In the CNS, CX3CL1 acts as a regulator of microglia activation in response to brain disorders or inflammation. Recently, there has been a growing interest in the role of CX3CL1 in regulating cell adhesion, chemotaxis, and host immune response in viral infection. Here, we provide a comprehensive review of the changes and function of CX3CL1 in various viral infections, such as human immunodeficiency virus (HIV), SARS-CoV-2, influenza virus, and cytomegalovirus (CMV) infection, to highlight the emerging roles of CX3CL1 in viral infection and associated diseases.

The spatial transcriptomic landscape of human gingiva in health and periodontitis

The gingiva is a key oral barrier that protects oral tissues from various stimuli. A loss of gingival tissue homeostasis causes periodontitis, one of the most prevalent inflammatory diseases in humans. The human gingiva exists as a complex cell network comprising specialized structures. To understand the tissue-specific pathophysiology of the gingiva, we applied a recently developed spatial enhanced resolution omics-sequencing (Stereo-seq) technique to obtain a spatial transcriptome (ST) atlas of the gingiva in healthy individuals and periodontitis patients. By utilizing Stereo-seq, we identified the major cell types present in the gingiva, which included epithelial cells, fibroblasts, endothelial cells, and immune cells, as well as subgroups of epithelial cells and immune cells. We further observed that inflammation-related signalling pathways, such as the JAK-STAT and NF-κB signalling pathways, were significantly upregulated in the endothelial cells of the gingiva of periodontitis patients compared with those of healthy individuals. Additionally, we characterized the spatial distribution of periodontitis risk genes in the gingiva and found that the expression of IFI16 was significantly increased in endothelial cells of inflamed gingiva. In conclusion, our Stereo-seq findings may facilitate the development of innovative therapeutic strategies for periodontitis by mapping periodontitis-relevant genes and pathways and effector cells.

Balancing macrophage polarization via stem cell-derived apoptotic bodies for diabetic wound healing

BACKGROUND

Adipose tissue-derived stem cell-derived apoptotic bodies (ADSC-ABs) have shown great potential for immunomodulation and regeneration, particularly in diabetic wound therapy. However, their local application has been limited by unclear regulatory mechanisms, rapid clearance, and short tissue retention times.

METHODS

We analyzed the key role molecules and regulatory pathways of ADSC-ABs in regulating inflammatory macrophages by mRNA sequencing and microRNA (miRNA) sequencing and then verified them by gene knockdown. To prevent rapid clearance, we employed microfluidics technology to prepare methacrylate-anhydride gelatin (GelMA) microspheres (GMS) for controlled release of ABs. Finally, we evaluated the effectiveness of ADSC-AB-laden GMSs (ABs@GMSs) in a diabetic rat wound model.

FINDINGS

Our results demonstrated that ADSC-ABs effectively balanced macrophage inflammatory polarization through the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, mediated by miR-20a-5p. Furthermore, we showed that AB@GMSs had good biocompatibility, significantly delayed local clearance of ABs, and ameliorated diabetic wound inflammation and promoted vascularization, thus facilitating its healing.

CONCLUSIONS

Our study reveals the regulatory mechanism of ADSC-ABs in balancing macrophage inflammatory polarization and highlightsthe importance of delaying their local clearance by GMSs. These findings have important implications for the development of novel therapies for diabetic wound healing.

FUNDING

This research was supported by the National Key Research and Development Program of China (2020YFA0908200), National Natural Science Foundation of China (82272263, 82002053, 32000937, and 82202467), Shanghai "Rising Stars of Medical Talents" Youth Development Program (22MC1940300), Shanghai Municipal Health Commission (20204Y0354), and Shanghai Science and Technology Development Funds (22YF1421400).

Immunomodulation of wound healing leading to efferocytosis

Effectively eliminating apoptotic cells is precisely controlled by a variety of signaling molecules and a phagocytic effect known as efferocytosis. Abnormalities in efferocytosis may bring about the development of chronic conditions, including angiocardiopathy, chronic inflammatory diseases and autoimmune diseases. During wound healing, failure of efferocytosis leads to the collection of apoptosis, the release of necrotic material and chronic wounds that are difficult to heal. In addition to the traditional phagocytes-macrophages, other important cell species including dendritic cells, neutrophils, vascular endothelial cells, fibroblasts and keratinocytes contribute to wounding healing. This review summarizes how efferocytosis-mediated immunomodulation plays a repair-promoting role in wound healing, providing new insights for patients suffering from various cutaneous wounds.

Punicalagin attenuates TNF-α-induced oxidative damage and promotes osteogenic differentiation of bone mesenchymal stem cells by activating the Nrf2/HO-1 pathway

Oxidative stress is one of the most important factors in changing bone homeostasis. Redox homeostasis plays a key role in the osteogenic differentiation of bone mesenchymal stem cells (BMSCs) and the angiogenesis ability of human umbilical vein endothelial cells (HUVECs) for bone regeneration. Currently, this study assessed the effects of punicalagin (PUN) on BMSCs and HUVECs. Cell viability was determined by CCK-8 assay. A flow cytometry analysis was adopted to detect macrophage polarization. The production of reactive oxygen stress (ROS), glutathione (GSH), malonaldehyde (MDA) and superoxide dismutase (SOD) activities were evaluated by using commercially-available kits. Osteogenic capacity of BMSCs was evaluated by ALP activity, ALP staining and ARS staining. The expression of osteogenic-related proteins (OCN, Runx-2, OPN) and Nrf/HO-1 levles were evaluated by Western blotting. Osteogenic-related genes (Osterix, COL-1, BMP-4, ALP) were evaluated by RT-PCR. Migration ability and invasion ability of HUVECs were evaluated by wound healing assay and Transwell assay. Angiogenic ability was detected by tube formation assay and the expression of angiogenic-related genes (VEGF, vWF, CD31) were evaluated by RT-PCR. Results showed that PUN alleviated oxidative stress by TNF-α, enhanced osteogenic differentiation in BMSCs and angiogenesis in HUVECs. Moreover, PUN regulate immune microenvironment by promoting the polarization of M2 macrophages and reduce the oxidative stress related products by activating Nrf2/HO-1 pathway. Altogether, these results suggested that PUN can promote osteogenic capacity of BMSCs, angiogenesis of HUVECs, alleviate oxidative stress via Nrf2/HO-1 pathway, offering PUN as a novel antioxidant agent for treating bone loss diseases.