Targeting SLC7A11 improves efferocytosis by dendritic cells and wound healing in diabetes

Blue light induced ferroptosis via STAT3/GPX4/SLC7A11/FTH1 in conjunctiva epithelium in vivo and in vitro

The prevalence of Light-emitting diodes (LEDs) has exposed us to an excessive amount of blue light (BL) which causes various ophthalmic diseases. Previous studies have shown that conjunctiva is vulnerable to BL. In this study, we aimed to investigate the underlying mechanism of BL-induced injury in conjunctiva. We placed C57BL/6 mice and human conjunctival epithelial cell lines (HCECs) under BL (440 nm ± 15 nm, 0.2 mW/cm2) to establish a BL injury model in vivo and in vitro. Immunohistochemistry and MDA assay were used to identify lipid peroxidation (LPO) in vivo. HE staining was applied to detect morphological damage of conjunctival epithelium. DCFH-DA, C11-BODIPY 581/591, Calcein-AM, and FeRhoNox™-1 probes were performed to identify ferroptosis levels in vitro. Real-time qPCR and Western blotting techniques were employed to uncover signaling pathways of blue light-induced ferroptosis. Our findings demonstrated that BL affected tear film instability and induced conjunctival epithelium injury in vivo. Ferrostatin-1 significantly alleviated blue light-induced ferroptosis in vivo and in vitro. BL downregulates the levels of solute carrier family 7 member 11 (SLC7A11), Ferritin heavy chain (FTH1), and glutathione peroxidase (GPX4) by inhibiting the activation and translocation of the Signal transducer and activator of transcription 3 (STAT3) from inducing Fe2+ burst, ROS and LPO accumulation, ultimately resulting in ferroptosis. This study will offer new insight into BL-induced conjunctival injury and LED-induced dry eye.

SLC7A11-ROS/αKG-AMPK axis regulates liver inflammation through mitophagy and impairs liver fibrosis and NASH progression

The changes of inflammation and metabolism are two features in nonalcoholic steatohepatitis (NASH). However, how they interact to regulate NASH progression remains largely unknown. Our works have demonstrated the importance of solute carrier family 7 member 11 (SLC7A11) in inflammation and metabolism. Nevertheless, whether SLC7A11 regulates NASH progression through mediating inflammation and metabolism is unclear. In this study, we found that SLC7A11 expression was increased in liver samples from patients with NASH. Upregulated SLC7A11 level was also detected in two murine NASH models. Functional studies showed that SLC7A11 knockdown or knockout had augmented steatohepatitis with suppression of inflammatory markers in mice. However, overexpression of SLC7A11 dramatically alleviated diet-induced NASH pathogenesis. Mechanically, SLC7A11 decreased reactive oxygen species (ROS) level and promoted α-ketoglutarate (αKG)/prolyl hydroxylase (PHD) activity, which activated AMPK pathway. Furthermore, SLC7A11 impaired expression of NLRP3 inflammasome components through AMPK-mitophagy axis. IL-1β release through NLRP3 inflammasome recruited myeloid cells and promoted hepatic stellate cells (HSCs) activation, which contributed to the progression of liver injury and fibrosis. Anti-IL-1β and anakinra might attenuate the hepatic inflammatory response evoked by SLC7A11 knockdown. Moreover, the upregulation of SLC7A11 in NASH was contributed by lipid overload-induced JNK-c-Jun pathway. In conclusions, SLC7A11 acts as a protective factor in controlling the development of NASH. Upregulation of SLC7A11 is protective by regulating oxidation, αKG and energy metabolism, decreasing inflammation and fibrosis.

A novel conductive microtubule hydrogel for electrical stimulation of chronic wounds based on biological electrical wires

Electrical stimulation (ES) is considered a promising therapy for chronic wounds via conductive dressing. However, the lack of a clinically suitable conductive dressing is a serious challenge. In this study, a suitable conductive biomaterial with favorable biocompatibility and conductivity was screened by means of an inherent structure derived from the body based on electrical conduction in vivo. Ions condensed around the surface of the microtubules (MTs) derived from the cell's cytoskeleton are allowed to flow in the presence of potential differences, effectively forming a network of biological electrical wires, which is essential to the bioelectrical communication of cells. We hypothesized that MT dressing could improve chronic wound healing via the conductivity of MTs applied by ES. We first developed an MT-MAA hydrogel by a double cross-linking method using UV and calcium chloride to improve chronic wound healing by ES. In vitro studies showed good conductivity, mechanical properties, biocompatibility, and biodegradability of the MT-MAA hydrogel, as well as an elevated secretion of growth factors with enhanced cell proliferation and migration ability in response to ES. The in vivo experimental results from a full-thickness diabetic wound model revealed rapid wound closure within 7d in C57BL/6J mice, and the wound bed dressed by the MT-MAA hydrogel was shown to have promoted re-epithelization, enhanced angiogenesis, accelerated nerve growth, limited inflammation phases, and improved antibacterial effect under the ES treatment. These preclinical findings suggest that the MT-MAA hydrogel may be an ideal conductive dressing for chronic wound healing. Furthermore, biomaterials based on MTs may be also promising for treating other diseases.

Janus liposozyme for the modulation of redox and immune homeostasis in infected diabetic wounds

Diabetic foot ulcers often become infected, leading to treatment complications and increased risk of loss of limb. Therapeutics to manage infection and simultaneously promote healing are needed. Here we report on the development of a Janus liposozyme that treats infections and promotes wound closure and re-epithelialization. The Janus liposozyme consists of liposome-like selenoenzymes for reactive oxygen species (ROS) scavenging to restore tissue redox and immune homeostasis. The liposozymes are used to encapsulate photosensitizers for photodynamic therapy of infections. We demonstrate application in methicillin-resistant Staphylococcus aureus-infected diabetic wounds showing high ROS levels for antibacterial function from the photosensitizer and nanozyme ROS scavenging from the liposozyme to restore redox and immune homeostasis. We demonstrate that the liposozyme can directly regulate macrophage polarization and induce a pro-regenerative response. By employing single-cell RNA sequencing, T cell-deficient Rag1-/- mice and skin-infiltrated immune cell analysis, we further reveal that IL-17-producing γδ T cells are critical for mediating M1/M2 macrophage transition. Manipulating the local immune homeostasis using the liposozyme is shown to be effective for skin wound repair and tissue regeneration in mice and mini pigs.

IL-13 facilitates ferroptotic death in asthmatic epithelial cells via SOCS1-mediated ubiquitinated degradation of SLC7A11

Th2-high asthma is characterized by elevated levels of type 2 cytokines, such as interleukin 13 (IL-13), and its prevalence has been increasing worldwide. Ferroptosis, a recently discovered type of programmed cell death, is involved in the pathological process of Th2-high asthma; however, the underlying mechanisms remain incompletely understood. In this study, we demonstrated that the serum level of malondialdehyde (MDA), an index of lipid peroxidation, positively correlated with IL-13 level and negatively correlated with the predicted forced expiratory volume in 1 s (FEV1%) in asthmatics. Furthermore, we showed that IL-13 facilitates ferroptosis by upregulating of suppressor of cytokine signaling 1 (SOCS1) through analyzing immortalized airway epithelial cells, human airway organoids, and the ovalbumin (OVA)-challenged asthma model. We identified that signal transducer and activator of transcription 6 (STAT6) promotes the transcription of SOCS1 upon IL-13 stimulation. Moreover, SOCS1, an E3 ubiquitin ligase, was found to bind to solute carrier family 7 member 11 (SLC7A11) and catalyze its ubiquitinated degradation, thereby promoting ferroptosis in airway epithelial cells. Last, we found that inhibiting SOCS1 can decrease ferroptosis in airway epithelial cells and alleviate airway hyperresponsiveness (AHR) in OVA-challenged wide-type mice, while SOCS1 overexpression exacerbated the above in OVA-challenged IL-13-knockout mice. Our findings reveal that the IL-13/STAT6/SOCS1/SLC7A11 pathway is a novel molecular mechanism for ferroptosis in Th2-high asthma, confirming that targeting ferroptosis in airway epithelial cells is a potential therapeutic strategy for Th2-high asthma.

Cell death as an architect of adult skin stem cell niches

Our skin provides a physical and immunological barrier against dehydration and environmental insults ranging from microbial attacks, toxins and UV irradiation to wounding. Proper functioning of the skin barrier largely depends on the interplay between keratinocytes- the epithelial cells of the skin- and immune cells. Two spatially distinct populations of keratinocyte stem cells (SCs) maintain the epidermal barrier function and the hair follicle. These SCs are inherently long-lived, but cell death can occur within their niches and impacts their functionality. The default cell death programme in skin is apoptosis, an orderly and non-inflammatory suicide programme. However, recent findings are shedding light on the significance of various modes of regulated necrotic cell death, which are lytic and can provoke inflammation within the local skin environment. While the presence of dying cells was generally regarded as a mere consequence of inflammation, findings in various human dermatological conditions and experimental mouse models of aberrant cell death control demonstrated that cell death programmes in keratinocytes (KCs) can drive skin inflammation and even tumour initiation. When cells die, they need to be removed by phagocytosis and KCs can function as non-professional phagocytes of apoptotic cells with important implications for their SC capacities. It is becoming apparent that in conditions of heightened SC activity, distinct cell death modalities differentially impact the different skin SC populations in their local niches. Here, we describe how regulated cell death modalities functionally affect epidermal SC niches along with their relevance to injury repair, inflammatory skin disorders and cancer.

Sweet regulation - The emerging immunoregulatory roles of hexoses

BACKGROUND

It is widely acknowledged that dietary habits have profound impacts on human health and diseases. As the most important sweeteners and energy sources in human diets, hexoses take part in a broad range of physiopathological processes. In recent years, emerging evidence has uncovered the crucial roles of hexoses, such as glucose, fructose, mannose, and galactose, in controlling the differentiation or function of immune cells.

AIM OF REVIEW

Herein, we reviewed the latest research progresses in the hexose-mediated modulation of immune responses, provided in-depth analyses of the underlying mechanisms, and discussed the unresolved issues in this field.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Owing to their immunoregulatory effects, hexoses affect the onset and progression of various types of immune disorders, including inflammatory diseases, autoimmune diseases, and tumor immune evasion. Thus, targeting hexose metabolism is becoming a promising strategy for reversing immune abnormalities in diseases.

CGRP sensory neurons promote tissue healing via neutrophils and macrophages

The immune system has a critical role in orchestrating tissue healing. As a result, regenerative strategies that control immune components have proved effective1,2. This is particularly relevant when immune dysregulation that results from conditions such as diabetes or advanced age impairs tissue healing following injury2,3. Nociceptive sensory neurons have a crucial role as immunoregulators and exert both protective and harmful effects depending on the context4-12. However, how neuro-immune interactions affect tissue repair and regeneration following acute injury is unclear. Here we show that ablation of the NaV1.8 nociceptor impairs skin wound repair and muscle regeneration after acute tissue injury. Nociceptor endings grow into injured skin and muscle tissues and signal to immune cells through the neuropeptide calcitonin gene-related peptide (CGRP) during the healing process. CGRP acts via receptor activity-modifying protein 1 (RAMP1) on neutrophils, monocytes and macrophages to inhibit recruitment, accelerate death, enhance efferocytosis and polarize macrophages towards a pro-repair phenotype. The effects of CGRP on neutrophils and macrophages are mediated via thrombospondin-1 release and its subsequent autocrine and/or paracrine effects. In mice without nociceptors and diabetic mice with peripheral neuropathies, delivery of an engineered version of CGRP accelerated wound healing and promoted muscle regeneration. Harnessing neuro-immune interactions has potential to treat non-healing tissues in which dysregulated neuro-immune interactions impair tissue healing.

Single-Cell RNA Sequencing Reveals RAC1 Involvement in Macrophages Efferocytosis in Diabetic Kidney Disease

Macrophage-mediated inflammation plays a significant role in the development and progression of diabetic kidney disease (DKD). Studies have suggested that impaired macrophage efferocytosis aggravates the inflammatory response. However, its contribution to DKD progression remains unknown. Using single-cell RNA sequencing (scRNA-seq) data obtained from the GSE131882, GSE195460, GSE151302, GSE195460, and GSE131685 datasets, we successfully clustered 13 cell types. Through analysis of the ligand-receptor network, it was discovered that macrophages interact with other cells. Additionally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that macrophages exhibit a heightened presence of phagocytosis signaling. We discovered that RAC1 was closely related to macrophage efferocytosis through a Venn diagram and protein-protein interaction (PPI) analysis, which predicted the correlation with the clinical features of DKD using the NephroseqV5 tool. Furthermore, we verified that RAC1 exhibited decreased expression in macrophages cultured with lipopolysaccharide (LPS) and high glucose. Nevertheless, the overexpression of RAC1 promoted macrophage efferocytosis and inhibited the inflammatory response. In summary, our study focused on examining the presence and importance of efferocytosis-related molecules in DKD macrophages. Through a comprehensive analysis using scRNA-seq, we discovered that RAC1 plays a crucial role as an efferocytosis molecule in DKD. These findings enhance our current knowledge of the molecular mechanisms involved in the development of DKD and aid the exploration of new treatments.

Hyperbaric oxygen therapy promotes the browning of white fat and contributes to the healing of diabetic wounds

Non-healing wounds are one of the chronic complications of diabetes and have remained a worldwide challenge as one of the major health problems. Hyperbaric oxygen (HBO) therapy is proven to be very successful for diabetic wound treatment, for which the molecular basis is not understood. Adipocytes regulate multiple aspects of repair and may be therapeutic for inflammatory diseases and defective wound healing associated with aging and diabetes. Endothelial cell-derived extracellular vesicles could promote wound healing in diabetes. To study the mechanism by which HBO promotes wound healing in diabetes, we investigated the effect of HBO on fat cells in diabetic mice. A diabetic wound mouse model was established and treated with HBO. Haematoxylin and eosin (H&E) staining and immunofluorescence were used for the analysis of wound healing. To further explore the mechanism, we performed whole-genome sequencing on extracellular vesicles (EVs). Furthermore, we conducted in vitro experiments. Specifically, exosomes were collected from human umbilical vein endothelial cell (HUVEC) cells after HBO treatment, and then these exosomes were co-incubated with adipose tissue. The wound healing rate in diabetic mice treated with HBO was significantly higher. HBO therapy promotes the proliferation of adipose precursor cells. HUVEC-derived exosomes treated with HBO significantly promoted fat cell browning. These data clarify that HBO therapy may promote vascular endothelial cell proliferation and migration, and promote browning of fat cells through vascular endothelial cells derived exosomes, thereby promoting diabetic wound healing. This provides new ideas for the application of HBO therapy in the treatment of diabetic trauma.

Rapid unleashing of macrophage efferocytic capacity via transcriptional pause release

During development, inflammation or tissue injury, macrophages may successively engulf and process multiple apoptotic corpses via efferocytosis to achieve tissue homeostasis1. How macrophages may rapidly adapt their transcription to achieve continuous corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved mechanism, in which RNA polymerase (Pol) II initiates transcription for 20-60 nucleotides, is paused for minutes to hours and is then released to make full-length mRNA2. Here we show that macrophages, within minutes of corpse encounter, use transcriptional pause/release to unleash a rapid transcriptional response. For human and mouse macrophages, the Pol II pause/release was required for continuous efferocytosis in vitro and in vivo. Interestingly, blocking Pol II pause/release did not impede Fc receptor-mediated phagocytosis, yeast uptake or bacterial phagocytosis. Integration of data from three genomic approaches-precision nuclear run-on sequencing, RNA sequencing, and assay for transposase-accessible chromatin using sequencing (ATAC-seq)-on efferocytic macrophages at different time points revealed that Pol II pause/release controls expression of select transcription factors and downstream target genes. Mechanistic studies on transcription factor EGR3, prominently regulated by pause/release, uncovered EGR3-related reprogramming of other macrophage genes involved in cytoskeleton and corpse processing. Using lysosomal probes and a new genetic fluorescent reporter, we identify a role for pause/release in phagosome acidification during efferocytosis. Furthermore, microglia from egr3-deficient zebrafish embryos displayed reduced phagocytosis of apoptotic neurons and fewer maturing phagosomes, supporting defective corpse processing. Collectively, these data indicate that macrophages use Pol II pause/release as a mechanism to rapidly alter their transcriptional programs for efficient processing of the ingested apoptotic corpses and for successive efferocytosis.

Biomaterials for immunomodulation in wound healing

The substantial economic impact of non-healing wounds, scarring, and burns stemming from skin injuries is evident, resulting in a financial burden on both patients and the healthcare system. This review paper provides an overview of the skin's vital role in guarding against various environmental challenges as the body's largest protective organ and associated developments in biomaterials for wound healing. We first introduce the composition of skin tissue and the intricate processes of wound healing, with special attention to the crucial role of immunomodulation in both acute and chronic wounds. This highlights how the imbalance in the immune response, particularly in chronic wounds associated with underlying health conditions such as diabetes and immunosuppression, hinders normal healing stages. Then, this review distinguishes between traditional wound-healing strategies that create an optimal microenvironment and recent peptide-based biomaterials that modulate cellular processes and immune responses to facilitate wound closure. Additionally, we highlight the importance of considering the stages of wounds in the healing process. By integrating advanced materials engineering with an in-depth understanding of wound biology, this approach holds promise for reshaping the field of wound management and ultimately offering improved outcomes for patients with acute and chronic wounds.

Construction of programmed time-released multifunctional hydrogel with antibacterial and anti-inflammatory properties for impaired wound healing

The successful reprogramming of impaired wound healing presents ongoing challenges due to the impaired tissue microenvironment caused by severe bacterial infection, excessive oxidative stress, as well as the inappropriate dosage timing during different stages of the healing process. Herein, a dual-layer hydrogel with sodium alginate (SA)-loaded zinc oxide (ZnO) nanoparticles and poly(N-isopropylacrylamide) (PNIPAM)-loaded Cu5.4O ultrasmall nanozymes (named programmed time-released multifunctional hydrogel, PTMH) was designed to dynamically regulate the wound inflammatory microenvironment based on different phases of wound repairing. PTMH combated bacteria at the early phase of infection by generating reactive oxygen species through ZnO under visible-light irradiation with gradual degradation of the lower layer. Subsequently, when the upper layer was in direct contact with the wound tissue, Cu5.4O ultrasmall nanozymes were released to scavenge excessive reactive oxygen species. This neutralized a range of inflammatory factors and facilitated the transition from the inflammatory phase to the proliferative phase. Furthermore, the utilization of Cu5.4O ultrasmall nanozymes enhanced angiogenesis, thereby facilitating the delivery of oxygen and nutrients to the impaired tissue. Our experimental findings indicate that PTMHs promote the healing process of diabetic wounds with bacterial infection in mice, exhibiting notable antibacterial and anti-inflammatory properties over a specific period of time.

The efferocytosis process in aging: Supporting evidence, mechanisms, and therapeutic prospects for age-related diseases

BACKGROUND

Aging is characterized by an ongoing struggle between the buildup of damage caused by a combination of external and internal factors. Aging has different effects on phagocytes, including impaired efferocytosis. A deficiency in efferocytosis can cause chronic inflammation, aging, and several other clinical disorders.

AIM OF REVIEW

Our review underscores the possible feasibility and extensive scope of employing dual targets in various age-related diseases to reduce the occurrence and progression of age-related diseases, ultimately fostering healthy aging and increasing lifespan. Key scientific concepts of review Hence, the concurrent implementation of strategies aimed at augmenting efferocytic mechanisms and anti-aging treatments has the potential to serve as a potent intervention for extending the duration of a healthy lifespan. In this review, we comprehensively discuss the concept and physiological effects of efferocytosis. Subsequently, we investigated the association between efferocytosis and the hallmarks of aging. Finally, we discuss growing evidence regarding therapeutic interventions for age-related disorders, focusing on the physiological processes of aging and efferocytosis.

Ferroptosis and oxidative stress in endometriosis: A systematic review of the literature

BACKGROUND

Endometriosis (EMT) a common gynecological condition in women, an inflammatory disease characterized by the presence of endometrial tissue on organs and tissues in the pelvis, and is mainly associated with chronic pelvic pain and infertility. As the etiology has not been fully elucidated, current treatment is limited to surgery, hormones and painkillers, with more side effects and difficulty in achieving long-term relief. Oxidative stress manifests itself as an overproduction of reactive oxygen species, which has an integral impact in the pathology of female reproductive disorders. In this review, we evaluate the mechanisms of iron overload-induced oxidative stress and ferroptosis in EMT and their pathophysiological implications.

METHODS

Because the etiology has not been fully elucidated, current treatments are limited to surgery, hormones, and painkillers, which have many side effects and are difficult to achieve long-term relief.

RESULTS

We interpreted that antioxidants as well as ferroptosis inducers show promising results in the treatment of EMT, but their application in this population needs to be further investigated.

CONCLUSION

In combination with the interpretation of previous studies, it was shown that iron overload is present in the peritoneal fluid, endometriotic lesions, peritoneum and macrophages in the abdominal cavity. However, the programmed cellular ferroptosis associated with iron overload is resisted by endometriotic foci, which is critical to the pathophysiology of EMT with local iron overload and inflammation.

Promoting Diabetic Wound Healing through a Hydrogel-Based Cascade Regulation Strategy of Fibroblast-Macrophage

The management of diabetic wounds (DWs) continues to pose a significant challenge in the field of medicine. DWs are primarily prevented from healing due to damage to macrophage efferocytosis and fibroblast dysfunction. Consequently, a treatment strategy that involves both immunoregulation and the promotion of extracellular matrix (ECM) formation holds promise for healing DWs. Nevertheless, existing treatment methods necessitate complex interventions and are associated with increased costs, for example, the use of cytokines and cell therapy, both of which have limited effectiveness. In this study, a new type of ruthenium (IV) oxide nanoparticles (RNPs)-laden hybrid hydrogel dressing with a double network of Pluronic F127 and F68 has been developed. Notably, the hybrid hydrogel demonstrates remarkable thermosensitivity, injectability, immunoregulatory characteristics, and healing capability. RNPs in hydrogel effectively regulate both fibroblasts and macrophages in a cascade manner, stimulating fibroblast differentiation while synergistically enhancing the efferocytosis of macrophage. The immunoregulatory character of the hydrogel aids in restoring the intrinsic stability of the immune microenvironment in the wound and facilitates essential remodeling of the ECM. This hydrogel therefore offers a novel approach for treating DWs through intercellular communication.

Nickel-Based Metal-Organic Frameworks Promote Diabetic Wound Healing via Scavenging Reactive Oxygen Species and Enhancing Angiogenesis

Chronic diabetic wounds remain a worldwide challenge for both the clinic and research. Given the vicious circle of oxidative stress and inflammatory response as well as the impaired angiogenesis of the diabetic wound tissues, the wound healing process is disturbed and poorly responds to the current treatments. In this work, a nickel-based metal-organic framework (MOF, Ni-HHTP) with excellent antioxidant activity and proangiogenic function is developed to accelerate the healing process of chronic diabetic wounds. The Ni-HHTP can mimic the enzymatic catalytic activities of antioxidant enzymes to eliminate multi-types of reactive species through electron transfer reactions, which protects cells from oxidative stress-related damage. Moreover, this Ni-based MOF can promote cell migration and angiogenesis by activating transforming growth factor-β1 (TGF-β1) in vitro and reprogram macrophages to the anti-inflammatory phenotype. Importantly, Ni-HHTP effectively promotes the healing process of diabetic wounds by suppressing the inflammatory response and enhancing angiogenesis in vivo. This study reports a versatile and promising MOF-based nanozyme for diabetic wound healing, which may be extended in combination with other wound dressings to enhance the management of diabetic or non-healing wounds.

Glycosaminoglycans' Ability to Promote Wound Healing: From Native Living Macromolecules to Artificial Biomaterials

Glycosaminoglycans (GAGs) are important for the occurrence of signaling molecules and maintenance of microenvironment within the extracellular matrix (ECM) in living tissues. GAGs and GAG-based biomaterial approaches have been widely explored to promote in situ tissue regeneration and repair by regulating the wound microenvironment, accelerating re-epithelialization, and controlling ECM remodeling. However, most approaches remain unacceptable for clinical applications. To improve insights into material design and clinical translational applications, this review highlights the innate roles and bioactive mechanisms of native GAGs during in situ wound healing and presents common GAG-based biomaterials and the adaptability of application scenarios in facilitating wound healing. Furthermore, challenges before the widespread commercialization of GAG-based biomaterials are shared, to ensure that future designed and constructed GAG-based artificial biomaterials are more likely to recapitulate the unique and tissue-specific profile of native GAG expression in human tissues. This review provides a more explicit and clear selection guide for researchers designing biomimetic materials, which will resemble or exceed their natural counterparts in certain functions, thereby suiting for specific environments or therapeutic goals.

Exosomes derived from impaired liver aggravate alveolar bone loss via shuttle of Fasn in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) exacerbates irreversible bone loss in periodontitis, but the mechanism of impaired bone regeneration caused by the abnormal metabolic process of T2DM remains unclear. Exosomes are regarded as the critical mediator in diabetic impairment of regeneration via organ or tissue communication. Here, we find that abnormally elevated exosomes derived from metabolically impaired liver in T2DM are significantly enriched in the periodontal region and induced pyroptosis of periodontal ligament cells (PDLCs). Mechanistically, fatty acid synthase (Fasn), the main differentially expressed molecule in diabetic exosomes results in ectopic fatty acid synthesis in PDLCs and activates the cleavage of gasdermin D. Depletion of liver Fasn effectively mitigates pyroptosis of PDLCs and alleviates bone loss. Our findings elucidate the mechanism of exacerbated bone loss in diabetic periodontitis and reveal the exosome-mediated organ communication in the "liver-bone" axis, which shed light on the prevention and treatment of diabetic bone disorders in the future.

Identification of SLC40A1, LCN2, CREB5, and SLC7A11 as ferroptosis-related biomarkers in alopecia areata through machine learning

Alopecia areata (AA) is a common non-scarring hair loss condition driven by the collapse of immune privilege and oxidative stress. The role of ferroptosis, a type of cell death linked to oxidative stress, in AA is yet to be explored, even though it's implicated in various diseases. Using transcriptome data from AA patients and controls from datasets GSE68801 and GSE80342, we aimed to identify AA diagnostic marker genes linked to ferroptosis. We employed Single-sample gene set enrichment analysis (ssGSEA) for immune cell infiltration evaluation. Correlations between ferroptosis-related differentially expressed genes (FRDEGs) and immune cells/functions were identified using Spearman analysis. Feature selection was done through Support vector machine-recursive feature elimination (SVM-RFE) and LASSO regression models. Validation was performed using the GSE80342 dataset, followed by hierarchical internal validation. We also constructed a nomogram to assess the predictive ability of FRDEGs in AA. Furthermore, the expression and distribution of these molecules were confirmed through immunofluorescence. Four genes, namely SLC40A1, LCN2, CREB5, and SLC7A11, were identified as markers for AA. A prediction model based on these genes showed high accuracy (AUC = 0.9052). Immunofluorescence revealed reduced expression of these molecules in AA patients compared to normal controls (NC), with SLC40A1 and CREB5 showing significant differences. Notably, they were primarily localized to the outer root sheath and in proximity to the sebaceous glands. Our study identified several ferroptosis-related genes associated with AA. These findings, emerging from the integration of immune cell infiltration analysis and machine learning, contribute to the evolving understanding of diagnostic and therapeutic strategies in AA. Importantly, this research lays a solid foundation for subsequent studies exploring the intricate relationship between AA and ferroptosis.

The interplay of miRNAs and ferroptosis in diseases related to iron overload

Ferroptosis has been conceptualized as a novel cell death modality distinct from apoptosis, necroptosis, pyroptosis and autophagic cell death. The sensitivity of cellular ferroptosis is regulated at multiple layers, including polyunsaturated fatty acid metabolism, glutathione-GPX4 axis, iron homeostasis, mitochondria and other parallel pathways. In addition, microRNAs (miRNAs) have been implicated in modulating ferroptosis susceptibility through targeting different players involved in the execution or avoidance of ferroptosis. A growing body of evidence pinpoints the deregulation of miRNA-regulated ferroptosis as a critical factor in the development and progression of various pathophysiological conditions related to iron overload. The revelation of mechanisms of miRNA-dependent ferroptosis provides novel insights into the etiology of diseases and offers opportunities for therapeutic intervention. In this review, we discuss the interplay of emerging miRNA regulators and ferroptosis players under different pathological conditions, such as cancers, ischemia/reperfusion, neurodegenerative diseases, acute kidney injury and cardiomyopathy. We emphasize on the relevance of miRNA-regulated ferroptosis to disease progression and the targetability for therapeutic interventions.

Butyrate enhances erastin-induced ferroptosis of lung cancer cells via modulating the ATF3/SLC7A11 pathway

Ferroptosis is a novel form of programmed cell death triggered by iron-dependent lipid peroxidation and has been associated with various diseases, including cancer. Erastin, an inhibitor of system Xc-, which plays a critical role in regulating ferroptosis, has been identified as an inducer of ferroptosis in cancer cells. In this study, we investigated the impact of butyrate, a short-chain fatty acid produced by gut microbiota, on erastin-induced ferroptosis in lung cancer cells. Our results demonstrated that butyrate significantly enhanced erastin-induced ferroptosis in lung cancer cells, as evidenced by increased lipid peroxidation and reduced expression of glutathione peroxidase 4 (GPX4). Mechanistically, we found that butyrate modulated the pathway involving activating transcription factor 3 (ATF3) and solute carrier family 7 member 11 (SLC7A11), leading to enhanced erastin-induced ferroptosis. Furthermore, partial reversal of the effect of butyrate on ferroptosis was observed upon knockdown of ATF3 or SLC7A11. Collectively, our findings indicate that butyrate enhances erastin-induced ferroptosis in lung cancer cells by modulating the ATF3/SLC7A11 pathway, suggesting its potential as a therapeutic agent for cancer treatment.

Interleukin-17 alleviates erastin-induced alveolar bone loss by suppressing ferroptosis via interaction between NRF2 and p-STAT3

AIM

To investigate the relationship between interleukin-17 (IL-17), ferroptosis and osteogenic differentiation.

MATERIALS AND METHODS

We first analysed the changes in ferroptosis-related molecules in experimental periodontitis models. The effects of erastin, a small-molecule ferroptosis inducer, and IL-17 on alveolar bone loss and repair in animal models were then investigated. Primary mouse mandibular osteoblasts were exposed to erastin and IL-17 in vitro. Ferroptosis- and osteogenesis-related genes and proteins were detected. Further, siRNA, immunofluorescence co-localization and immunoprecipitation were used to confirm the roles of the nuclear factor erythroid-2-related factor 2 (NRF2) and phosphorylated signal transducer and activator of transcription 3 (p-STAT3), as well as their interaction.

RESULTS

The levels of NRF2, glutathione peroxidase 4 and solute carrier family 7 member 11 were lower in the ligated tissues than in normal periodontal tissues. Alveolar bone loss in an in vivo experimental periodontitis model was aggravated by erastin and alleviated by IL-17. In vitro, IL-17 ameliorated erastin-inhibited osteogenic differentiation by reversing ferroptosis. Altered NRF2 expression correlated with changes in ferroptosis-related molecules and osteogenesis. Furthermore, the physical interaction between NRF2 and p-STAT3 was confirmed in the nucleus. In IL-17 + erastin-stimulated osteoblasts, the p-STAT3-NRF2 complex might actively participate in the downstream transcription of ferroptosis- and osteogenesis-related genes.

CONCLUSIONS

IL-17 administration conferred resistance to erastin-induced osteoblast ferroptosis and osteogenesis. The possible mechanism may involve p-STAT3 directly interacting with NRF2.

Role of solute carrier transporters in regulating dendritic cell maturation and function

Dendritic cells (DCs) are specialized antigen-presenting cells that initiate and regulate innate and adaptive immune responses. Solute carrier (SLC) transporters mediate diverse physiological functions and maintain cellular metabolite homeostasis. Recent studies have highlighted the significance of SLCs in immune processes. Notably, upon activation, immune cells undergo rapid and robust metabolic reprogramming, largely dependent on SLCs to modulate diverse immunological responses. In this review, we explore the central roles of SLC proteins and their transported substrates in shaping DC functions. We provide a comprehensive overview of recent studies on amino acid transporters, metal ion transporters, and glucose transporters, emphasizing their essential contributions to DC homeostasis under varying pathological conditions. Finally, we propose potential strategies for targeting SLCs in DCs to bolster immunotherapy for a spectrum of human diseases.

Targeting Efferocytosis in Inflammaging

Rapid removal of apoptotic cells by phagocytes, a process known as efferocytosis, is key for the maintenance of tissue homeostasis, the resolution of inflammation, and tissue repair. However, impaired efferocytosis can result in the accumulation of apoptotic cells, subsequently triggering sterile inflammation through the release of endogenous factors such as DNA and nuclear proteins from membrane permeabilized dying cells. Here, we review the molecular basis of the three key phases of efferocytosis, that is, the detection, uptake, and degradation of apoptotic materials by phagocytes. We also discuss how defects in efferocytosis due to the alteration of phagocytes and dying cells can contribute to the low-grade chronic inflammation that occurs during aging, described as inflammaging. Lastly, we explore opportunities in targeting and harnessing the efferocytic machinery to limit aging-associated inflammatory diseases.

Identification of sulfur metabolism-related gene signature in osteoarthritis and TM9SF2's sustenance effect on M2 macrophages' phagocytic activity

BACKGROUND

Osteoarthritis (OA) is a chronic and low-grade inflammatory disease associated with metabolism disorder and multiple cell death types in the synovial tissues. Sulfur metabolism has not been studied in OA.

METHODS

First, we calculated the single sample gene set enrichment analysis score of sulfur metabolism-associated annotations (i.e., cysteine metabolism process, regulation of sulfur metabolism process, and disulfidptosis) between healthy and synovial samples from patients with OA. Sulfur metabolism-related differentially expressed genes (DEGs) were analyzed in OA. Least absolute shrinkage and selection operator COX regression were used to identify the sulfur metabolism-associated gene signature for diagnosing OA. Correlation and immune cell deconvolution analyses were used to explore the correlated functions and cell specificity of the signature gene, TM9SF2. TM9SF2's effect on the phagocytosis of macrophages M2 was analyzed by coculturing macrophages with IgG-coated beads or apoptotic Jurkat cells.

RESULTS

A diagnostic six gene signature (i.e., MTHFD1, PDK4, TM9SF2, POU4F1, HOXA2, NCKAP1) was identified based on the ten DEGs, validated using GSE12021 and GSE1919 datasets. TM9SF2 was upregulated in the synovial tissues of OA at both mRNA and protein levels. The relationship between TM9SF2 and several functional annotations, such as antigen processing and presentation, lysosome, phagosome, Fcγ-mediated phagocytosis, and tyrosine metabolism, was identified. TM9SF2 and macrophages M2 were significantly correlated. After silencing TM9SF2 in THP-1-derived macrophages M2, a significantly reduced phagocytosis and attenuated activation of PLC-γ1 were observed.

CONCLUSION

A sulfur metabolism-associated six-gene signature for OA diagnosis was constructed and upregulation of the phagocytosis-associated gene, TM9SF2, was identified. The findings are expected to deepen our understanding of the molecular mechanism underlying OA development and be used as potential therapeutic targets.

Microcurrent Cloth-Assisted Transdermal Penetration and Follicular Ducts Escape of Curcumin-Loaded Micelles for Enhanced Wound Healing

Purpose

Larger nanoparticles of bioactive compounds deposit high concentrations in follicular ducts after skin penetration. In this study, we investigated the effects of microcurrent cloth on the skin penetration and translocation of large nanoparticle applied for wound repair applications.

Methods

A self-assembly of curcumin-loaded micelles (CMs) was prepared to improve the water solubility and transdermal efficiency of curcumin. Microcurrent cloth (M) was produced by Zn/Ag electrofabric printing to facilitate iontophoretic transdermal delivery. The transdermal performance of CMs combined with M was evaluated by a transdermal system and confocal microscopy. The CMs/iontophoretic combination effects on nitric oxide (NO) production and inflammatory cytokines were evaluated in Raw 264.7 cells. The wound-healing property of the combined treatment was assessed in a surgically created full-thickness circular wound mouse model.

Results

Energy-dispersive X-ray spectroscopy confirmed the presence of Zn/Ag on the microcurrent cloth. The average potential of M was measured to be +214.6 mV in PBS. Large particle CMs (CM-L) prepared using surfactant/cosurfactant present a particle size of 142.9 nm with a polydispersity index of 0.319. The solubility of curcumin in CM-L was 2143.67 μg/mL, indicating 250-fold higher than native curcumin (8.68 μg/mL). The combined treatment (CM-L+M) demonstrated a significant ability to inhibit NO production and increase IL-6 and IL-10 secretion. Surprisingly, microcurrent application significantly improved 20.01-fold transdermal performance of curcumin in CM-L with an obvious escape of CM-L from follicular ducts to surrounding observed by confocal microscopy. The CM-L+M group also exhibited a better wound-closure rate (77.94% on day 4) and the regenerated collagen intensity was approximately 2.66-fold higher than the control group, with a closure rate greater than 90% on day 8 in vivo.

Conclusion

Microcurrent cloth play as a promising iontophoretic transdermal drug delivery accelerator that enhances skin penetration and assists CMs to escape from follicular ducts for wound repair applications.

Glucose-responsive, antioxidative HA-PBA-FA/EN106 hydrogel enhanced diabetic wound healing through modulation of FEM1b-FNIP1 axis and promoting angiogenesis

The diabetic wounds remain to be unsettled clinically, with chronic wounds characterized by drug-resistant bacterial infections, compromised angiogenesis and oxidative damage to the microenvironment. To ameliorate oxidative stress and applying antioxidant treatment in the wound site, we explore the function of folliculin-interacting protein 1 (FNIP1), a mitochondrial gatekeeper protein works to alter mitochondrial morphology, reduce oxidative phosphorylation and protect cells from unwarranted ROS accumulation. And our in vitro experiments showed the effects of FNIP1 in ameliorating oxidative stress and rescued impaired angiogenesis of HUVECs in high glucose environment. To realize the drug delivery and local regulation of FNIP1 in diabetic wound sites, a novel designed glucose-responsive HA-PBA-FA/EN106 hydrogel is introduced for improving diabetic wound healing. Due to the dynamic phenylboronate ester structure with a phenylboronic acid group between hyaluronic acid (HA) and phenylboronic acid (PBA), the hydrogel is able to realize a glucose-responsive release of drugs. Fulvic acid (FA) is added in the hydrogel, which not only severs as crosslinking agent but also provides antibacterial and anti-inflammatory abilities. Moreover, the release of FEM1b-FNIP1 axis inhibitor EN106 ameliorated oxidative stress and stimulated angiogenesis through FEM1b-FNIP1 axis regulation. These in vivo and in vitro results demonstrated that accelerated diabetic wounds repair with the use of the HA-PBA-FA/EN106 hydrogel, which may provide a promising strategy for chronic diabetic wound repair.

Defining solute carrier transporter signatures of murine immune cell subsets

Solute carrier (SLC) transporters are membrane-bound proteins that facilitate nutrient transport, and the movement across cellular membranes of various substrates ranging from ions to amino acids, metabolites and drugs. Recently, SLCs have gained increased attention due to their functional linkage to innate immunological processes such as the clearance of dead cells and anti-microbial defense. Further, the druggable nature of these transporters provides unique opportunities for improving outcomes in different immunological diseases. Although the SLCs represent the largest group of transporters and are often identified as significant hits in omics data sets, their role in immunology has been insufficiently explored. This is partly due to the absence of tools that allow identification of SLC expression in particular immune cell types and enable their comparison before embarking on functional studies. In this study, we used publicly available RNA-Seq data sets to analyze the transcriptome in adaptive and innate immune cells, focusing on differentially and highly expressed SLCs. This revealed several new insights: first, we identify differentially expressed SLC transcripts in phagocytes (macrophages, dendritic cells, and neutrophils) compared to adaptive immune cells; second, we identify new potential immune cell markers based on SLC expression; and third, we provide user-friendly online tools for researchers to explore SLC genes of interest (and the rest of the genes as well), in three-way comparative dot plots among immune cells. We expect this work to facilitate SLC research and comparative transcriptomic studies across different immune cells.

Construction and validation of an efferocytosis-related prognostic signature in lung adenocarcinoma

BACKGROUND

Accumulating evidence highlights the potential significance of efferocytosis in tumor progression. This study is directed towards the construction of a prognostic risk model for lung adenocarcinoma (LUAD), grounded on efferocytosis-related genes (ERGs).

METHODS

Employing LASSO-COX regression analysis, a risk-prognostic model was formulated, centered on seven ERGs. Concurrently, a nomogram was established that incorporated patient clinical features and risk scores. The predictive accuracy of the risk model and the nomogram was substantiated via external validation sets. The landscapes of immune infiltration and genetic mutation were evaluated for high- and low-risk groups, with the expression of seven key genes validated through RT-PCR.

RESULTS

Our findings reveal that the high-risk group displayed considerably inferior survival outcomes in comparison to the low-risk group. A diminished abundance of immune cell infiltrates and a higher prevalence of gene mutations characterized the high-risk group. Genes with high expression were markedly enriched in pathways related to cell proliferation. The superior predictive performance of the risk model and nomogram was adequately substantiated by the external validation sets (GSE31210, GSE30219, and GSE50081). In addition, we discerned several potential therapeutic drugs demonstrating different sensitivities across patient risk groups. The differential expression of seven central genes was confirmed in A549, H1299, and BEAS-2B cell lines.

CONCLUSION

The constructed risk model and nomogram display high accuracy in predicting the survival and immune landscape of LUAD patients, thus providing invaluable prognostic tools in clinical scenarios.

Efferocytosis: An accomplice of cancer immune escape

The clearance of apoptotic cells by efferocytes such as macrophages and dendritic cells is termed as "efferocytosis", it plays critical roles in maintaining tissue homeostasis in multicellular organisms. Currently, available studies indicate that efferocytosis-related molecules and pathways are tightly associated with cancer development, metastasis and treatment resistance, efferocytosis also induces an immunosuppressive tumor microenvironment and assists cancer cells escape from immune surveillance. In this study, we reviewed the underlying mechanisms of efferocytosis in mediating the occurrence of cancer immune escape, and then emphatically summarized the strategies of using efferocytosis as therapeutic target to enhance the anti-tumor efficacies of immune checkpoint inhibitors, hoping to provide powerful evidences for more effective therapeutic regimens of malignant tumors.

Autophagy critically controls skin inflammation and apoptosis-induced stem cell activation

Macroautophagy/autophagy is a cellular recycling program regulating cell survival and controlling inflammatory responses in a context-dependent manner. Here, we demonstrate that keratinocyte-selective ablation of Atg16l1, an essential autophagy mediator, results in exacerbated inflammatory and neoplastic skin responses. In addition, mice lacking keratinocyte autophagy exhibit precocious onset of hair follicle growth, indicating altered activation kinetics of hair follicle stem cells (HFSCs). These HFSCs also exhibit expanded potencies in an autophagy-deficient context as shown by de novo hair follicle formation and improved healing of abrasion wounds. ATG16L1-deficient keratinocytes are markedly sensitized to apoptosis. Compound deletion of RIPK3-dependent necroptotic and CASP8-dependent apoptotic responses or of TNFRSF1A/TNFR1 reveals that the enhanced sensitivity of autophagy-deficient keratinocytes to TNF-dependent cell death is driving altered activation of HFSCs. Together, our data demonstrate that keratinocyte autophagy dampens skin inflammation and tumorigenesis but curtails HFSC activation by restraining apoptotic responses.Abbreviations: ATG16L1: autophagy related 16 like 1; DMBA: 2,4-dimethoxybenzaldehyde; DP: dermal papilla; EpdSCs: epidermal stem cells; Gas6: growth arrest specific 6; HF: hair follicle; HFSC: hair follicle stem cell; IFE: interfollicular epidermis; KRT5: keratin 5; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; PMK: primary mouse keratinocyte; RIPK3: receptor-interacting serine-threonine kinase 3; scRNAseq: single-cell RNA-sequencing; SG: sebaceous gland; TEWL: transepidermal water loss; TPA: 12-O-tetradecanoylphorbol-13-acetate; TNF: tumor necrosis factor; TNFRSF1A/TNFR1: tumor necrosis factor receptor superfamily, member 1a; UMAP: uniform manifold approximation and projection.

Ginsenoside Rg5 promotes wound healing in diabetes by reducing the negative regulation of SLC7A11 on the efferocytosis of dendritic cells

Background: ginsenoside Rg5 is a rare ginsenoside with known hypoglycemic effects in diabetic mice. This study aimed to explore the effects of ginsenoside Rg5 on skin wound-healing in the Leprdb/db mutant (db/db) mice (C57BL/KsJ background) model and the underlying mechanisms.

Methods

Seven-week-old male C57BL/6J, SLC7A11-knockout (KO), the littermate wild-type (WT), and db/db mice were used for in vivo and ex vivo studies.

Results

Ginsenoside Rg5 provided through oral gavage in db/db mice significantly alleviated the abundance of apoptotic cells in the wound areas and facilitated skin wound healing. 50 μM ginsenoside Rg5 treatment nearly doubled the efferocytotic capability of bone marrow-derived dendritic cells (BMDCs) from db/db mice. It also reduced NF-κB p65 and SLC7A11 expression in the wounded areas of db/db mice dose-dependently. Ginsenoside Rg5 physically interacted with SLC7A11 and suppressed the cystine uptake and glutamate secretion of BMDCs from db/db and SLC7A11-WT mice but not in BMDCs from SLC7A11-KO mice. In BMDCs and conventional type 1 dendritic cells (cDC1s), ginsenoside Rg5 reduced their glycose storage and enhanced anaerobic glycolysis. Glycogen phosphorylase inhibitor CP-91149 almost abolished the effect of ginsenoside Rg5 on promoting efferocytosis. Conclusion: ginsenoside Rg5 can suppress the expression of SLC7A11 and inhibit its activity via physical binding. These effects collectively alleviate the negative regulations of SLC7A11 on anaerobic glycolysis, which fuels the efferocytosis of dendritic cells. Therefore, ginsenoside Rg5 has a potential adjuvant therapeutic reagent to support patients with wound-healing problems, such as diabetic foot ulcers.

Immunometabolism of dendritic cells in health and disease

Dendritic cells (DCs) are crucial mediators that bridge the innate and adaptive immune responses. Cellular rewiring of metabolism is an emerging regulator of the activation, migration, and functional specialization of DC subsets in specific microenvironments and immunological conditions. DCs undergo metabolic adaptation to exert immunogenic or tolerogenic effects in different contexts. Also, beyond their intracellular metabolic and signaling roles, metabolites and nutrients mediate the intercellular crosstalk between DCs and other cell types, and such crosstalk orchestrates DC function and immune responses. Here, we provide a comprehensive review of the metabolic regulation of DC biology in various contexts and summarize the current understanding of such regulation in directing immune homeostasis and inflammation, specifically with respect to infections, autoimmunity, tolerance, cancer, metabolic diseases, and crosstalk with gut microbes. Understanding context-specific metabolic alterations in DCs may identify mechanisms for physiological and pathological functions of DCs and yield potential opportunities for therapeutic targeting of DC metabolism in many diseases.

Tanshinone IIA alleviates atherosclerosis in LDLR-/- mice by regulating efferocytosis of macrophages

Background: Tanshinone IIA (TIIA) is the major lipid-soluble active ingredient of the traditional Chinese medicine Salvia miltiorrhiza, which slows down atherosclerosis (AS). However, it remains unclear whether TIIA has the potential to enhance macrophage efferocytosis and thereby improve atherosclerosis. Objective: The focus of this examination was to determine if TIIA could reduce lipid accumulation and treat AS by enhancing efferocytosis. Methods: Firstly, we conducted in vivo experiments using LDLR knockout (LDLR-/-) mice for a period of 24 weeks, using histopathological staining, immunofluorescence and Western blot experiments to validate from the efficacy and mechanism parts, respectively; in addition, we utilized cells to validate our study again in vitro. The specific experimental design scheme is as follows: In vivo, Western diet-fed LDLR-/- mice for 12 weeks were constructed as an AS model, and normal diet-fed LDLR-/- mice were taken as a blank control group. The TIIA group and positive control group (atorvastatin, ATO) were intervened for 12 weeks by intraperitoneal injection (15 mg/kg/d) and gavage (1.3 mg/kg/d), respectively. In vitro, RAW264.7 cells were cultured with ox-LDL (50 ug/mL) or ox-LDL (50 ug/mL) + TIIA (20 uM/L or 40 uM/L). Pathological changes in aortic plaques and foam cell formation in RAW264.7 cells were evaluated using Masson and Oil Red O staining, respectively. Biochemical methods were used to detect lipid levels in mice. The immunofluorescence assay was performed to detect apoptotic cells and efferocytosis-related signal expression at the plaques. RT-qPCR and Western blot were carried out to observe the trend change of efferocytosis-related molecules in both mouse aorta and RAW264.7 cells. We also used the neutral red assay to assess RAW264.7 cells' phagocytic capacity. Results: Compared with the model group, TIIA decreased serum TC, TG, and LDL-C levels (p < 0.01), reduced the relative lumen area of murine aortic lipid-rich plaques (p < 0.01), enhanced the stability of murine aortic plaques (p < 0.01), reduced ox-LDL-induced lipid build-up in RAW264.7 cells (p < 0.01), and upregulated efferocytosis-related molecules expression and enhance the efferocytosis rate of ox-LDL-induced RAW264.7 cells. Conclusion: TIIA might reduce lipid accumulation by enhancing the efferocytosis of macrophages and thus treat AS.

Graphene-Based Material-Mediated Immunomodulation in Tissue Engineering and Regeneration: Mechanism and Significance

Tissue engineering and regenerative medicine hold promise for improving or even restoring the function of damaged organs. Graphene-based materials (GBMs) have become a key player in biomaterials applied to tissue engineering and regenerative medicine. A series of cellular and molecular events, which affect the outcome of tissue regeneration, occur after GBMs are implanted into the body. The immunomodulatory function of GBMs is considered to be a key factor influencing tissue regeneration. This review introduces the applications of GBMs in bone, neural, skin, and cardiovascular tissue engineering, emphasizing that the immunomodulatory functions of GBMs significantly improve tissue regeneration. This review focuses on summarizing and discussing the mechanisms by which GBMs mediate the sequential regulation of the innate immune cell inflammatory response. During the process of tissue healing, multiple immune responses, such as the inflammatory response, foreign body reaction, tissue fibrosis, and biodegradation of GBMs, are interrelated and influential. We discuss the regulation of these immune responses by GBMs, as well as the immune cells and related immunomodulatory mechanisms involved. Finally, we summarize the limitations in the immunomodulatory strategies of GBMs and ideas for optimizing GBM applications in tissue engineering. This review demonstrates the significance and related mechanism of the immunomodulatory function of GBM application in tissue engineering; more importantly, it contributes insights into the design of GBMs to enhance wound healing and tissue regeneration in tissue engineering.

Cystine/Glutamate antiporter system xc- deficiency impairs macrophage glutathione metabolism and cytokine production

System xc-, encoded by Slc7a11, is an antiporter responsible for exporting glutamate while importing cystine, which is essential for protein synthesis and the formation of thiol peptides, such as glutathione. Glutathione acts as a co-factor for enzymes responsible for scavenging reactive oxygen species. Upon exposure to bacterial products, macrophages exhibit a rapid upregulation of system xc-. This study investigates the impact of Slc7a11 deficiency on the functionality of peritoneal and bone marrow-derived macrophages. Our findings reveal that the absence of Slc7a11 results in significantly reduced glutathione levels, compromised mitochondrial flexibility, and hindered cytokine production in bone marrow-derived macrophages. Conversely, system xc- has a lesser impact on peritoneal macrophages in vivo. These results indicate that system xc- is essential for maintaining glutathione levels, mitochondrial functionality, and cytokine production, with a heightened importance under atmospheric oxygen tension.

Inflammation-Responsive Hydrogel Spray for Synergistic Prevention of Traumatic Heterotopic Ossification via Dual-Homeostatic Modulation Strategy

Traumatic heterotopic ossification (THO) represents one of the most prominent contributors to post-traumatic joint dysfunction, which currently lacks an effective and definitive preventative approach. Inflammatory activation due to immune dyshomeostasis during the early stages of trauma is believed to be critical in initiating the THO disease process. This study proposes a dual-homeostatic modulation (DHM) strategy to synergistically prevent THO without compromising normal trauma repair by maintaining immune homeostasis and inducing stem cell homeostasis. A methacrylate-hyaluronic acid-based hydrogel spray device encapsulating a curcumin-loaded zeolitic imidazolate framework-8@ceric oxide (ZIF-8@CeO2, CZC) nanoparticles (CZCH) is designed. Photo-crosslinked CZCH is used to form hydrogel films fleetly in periosteal soft tissues to achieve sustained curcumin and CeO2 nanoparticles release in response to acidity and reactive oxygen species (ROS) in the inflammatory microenvironment. In vitro experiments and RNA-seq results demonstrated that CZCH achieved dual-homeostatic regulation of inflammatory macrophages and stem cells through immune repolarization and enhanced efferocytosis, maintaining immune cell homeostasis and normal differentiation. These findings of the DHM strategy are also validated by establishing THO mice and rat models. In conclusion, the CZCH hydrogel spray developed based on the DHM strategy enables synergistic THO prevention, providing a reference for a standard procedure of clinical operations.

Reactive Oxygen Species-Scavenging Nanosystems in the Treatment of Diabetic Wounds

Diabetic wounds are characterized by drug-resistant bacterial infections, biofilm formation, impaired angiogenesis and perfusion, and oxidative damage to the microenvironment. Given their complex nature, diabetic wounds remain a major challenge in clinical practice. Reactive oxygen species (ROS), which have been shown to trigger hyperinflammation and excessive cellular apoptosis, play a pivotal role in the pathogenesis of diabetic wounds. ROS-scavenging nanosystems have recently emerged as smart and multifunctional nanomedicines with broad synergistic applicability. The documented anti-inflammatory and pro-angiogenic ability of ROS-scavenging treatments predestines these nanosystems as promising options for the treatment of diabetic wounds. Yet, in this context, the therapeutic applicability and efficacy of ROS-scavenging nanosystems remain to be elucidated. Herein, the role of ROS in diabetic wounds is deciphered, and the properties and strengths of nanosystems with ROS-scavenging capacity for the treatment of diabetic wounds are summarized. In addition, the current challenges of such nanosystems and their potential future directions are discussed through a clinical-translational lens.

Stem Cells and Exosome Applications for Cutaneous Wound Healing: From Ground to Microgravity Environment

The increasing number of astronauts entering microgravity environments for long-term space missions has resulted in serious health problems, including accidental injury and trauma. Skin, as the largest organ and outermost layer of the human body, has the ability to self-renew and withstand a variety of harmful biological and environmental influences. Recent spaceflight experiments and simulated studies have begun to concern the effects of microgravity on the growth of skin cells and the process of cutaneous wound healing. However, the mechanisms of the adverse effects of microgravity on skin cells and potential intervention measures are still limited. Stem cells and their exosomes provide unique opportunities for the cutaneous wound healing as they have been used to improve skin repair. This review discusses the effects of microgravity on wound healing, from cell morphological changes to molecular level alterations. Furthermore, the current research on wound healing treatment utilizing stem cells and their exosomes on the ground is summarized. Finally, this review proposes promising therapeutic strategies using stem cells or exosomes for wound healing in the microgravity environment. Graphical Abstract.

PDK4 facilitates fibroblast functions and diabetic wound healing through regulation of HIF-1α protein stability and gene expression

Fibroblast activation disorder is one of the main pathogenic characteristics of diabetic wounds. Orchestrated fibroblast functions and myofibroblast differentiation are crucial for wound contracture and extracellular matrix (ECM) formation. Pyruvate dehydrogenase kinase 4 (PDK4), a key enzyme regulating energy metabolism, has been implicated in modulating fibroblast function, but its specific role in diabetic wounds remains poorly understood. In this study, we investigated the impact of PDK4 on diabetic wounds and its underlying mechanisms. To assess the effect of PDK4 on human dermal fibroblasts (HDFs), we conducted CCK-8, EdU proliferation assay, wound healing assay, transwell assay, flow cytometry, and western blot analyses. Metabolic shifts were analyzed using the Seahorse XF analyzer, while changes in metabolite expression were measured through LC-MS. Local recombinant PDK4 administration was implemented to evaluate its influence on wound healing in diabetic mice. Finally, we found that sufficient PDK4 expression is essential for a normal wound-healing process, while PDK4 is low expressed in diabetic wound tissues and fibroblasts. PDK4 promotes proliferation, migration, and myofibroblast differentiation of HDFs and accelerates wound healing in diabetic mice. Mechanistically, PDK4-induced metabolic reprogramming increases the level of succinate that inhibits PHD2 enzyme activity, thus leading to the stability of the HIF-1α protein, during which process the elevated HIF-1α mRNA by PDK4 is also indispensable. In conclusion, PDK4 promotes fibroblast functions through regulation of HIF-1α protein stability and gene expression. Local recombinant PDK4 administration accelerates wound healing in diabetic mice.

Cardiac macrophages and emerging roles for their metabolism after myocardial infarction

Interest in cardioimmunology has reached new heights as the experimental cardiology field works to tap the unrealized potential of immunotherapy for clinical care. Within this space is the cardiac macrophage, a key modulator of cardiac function in health and disease. After a myocardial infarction, myeloid macrophages both protect and harm the heart. To varying degrees, such outcomes are a function of myeloid ontogeny and heterogeneity, as well as functional cellular plasticity. Diversity is further shaped by the extracellular milieu, which fluctuates considerably after coronary occlusion. Ischemic limitation of nutrients constrains the metabolic potential of immune cells, and accumulating evidence supports a paradigm whereby macrophage metabolism is coupled to divergent inflammatory consequences, although experimental evidence for this in the heart is just emerging. Herein we examine the heterogeneous cardiac macrophage response following ischemic injury, with a focus on integrating putative contributions of immunometabolism and implications for therapeutically relevant cardiac injury versus cardiac repair.

Electrostatically assembled wound dressings deliver pro-angiogenic anti-miRs preferentially to endothelial cells

Chronic non-healing wounds occur frequently in individuals affected by diabetes, yet standard-of-care treatment leaves many patients inadequately treated or with recurring wounds. MicroRNA (miR) expression is dysregulated in diabetic wounds and drives an anti-angiogenic phenotype, but miRs can be inhibited with short, chemically-modified RNA oligonucleotides (anti-miRs). Clinical translation of anti-miRs is hindered by delivery challenges such as rapid clearance and uptake by off-target cells, requiring repeated injections, excessively large doses, and bolus dosing mismatched to the dynamics of the wound healing process. To address these limitations, we engineered electrostatically assembled wound dressings that locally release anti-miR-92a, as miR-92a is implicated in angiogenesis and wound repair. In vitro, anti-miR-92a released from these dressings was taken up by cells and inhibited its target. An in vivo cellular biodistribution study in murine diabetic wounds revealed that endothelial cells, which play a critical role in angiogenesis, exhibit higher uptake of anti-miR eluted from coated dressings than other cell types involved in the wound healing process. In a proof-of-concept efficacy study in the same wound model, anti-miR targeting anti-angiogenic miR-92a de-repressed target genes, increased gross wound closure, and induced a sex-dependent increase in vascularization. Overall, this proof-of-concept study demonstrates a facile, translational materials approach for modulating gene expression in ulcer endothelial cells to promote angiogenesis and wound healing. Furthermore, we highlight the importance of probing cellular interactions between the drug delivery system and the target cells to drive therapeutic efficacy.

Sulfur metabolic response in macrophage limits excessive inflammatory response by creating a negative feedback loop

The excessive inflammatory response of macrophages plays a vital role in the pathogenesis of various diseases. The dynamic metabolic alterations in macrophages, including amino acid metabolism, are known to orchestrate their inflammatory phenotype. To explore a new metabolic pathway that regulates the inflammatory response, we examined metabolome changes in mouse peritoneal macrophages (PMs) in response to lipopolysaccharide (LPS) and found a coordinated increase of cysteine and its related metabolites, suggesting an enhanced demand for cysteine during the inflammatory response. Because Slc7a11, which encodes a cystine transporter xCT, was remarkably upregulated upon the pro-inflammatory challenge and found to serve as a major channel of cysteine supply, we examined the inflammatory behavior of Slc7a11 knockout PMs (xCT-KO PMs) to clarify an impact of the increased cysteine demand on inflammation. The xCT-KO PMs exhibited a prolonged upregulation of pro-inflammatory genes, which was recapitulated by cystine depletion in the culture media of wild-type PMs, suggesting that cysteine facilitates the resolution of inflammation. Detailed analysis of the sulfur metabolome revealed that supersulfides, such as cysteine persulfide, were increased in PMs in response to LPS, which was abolished in xCT-KO PMs. Supplementation of N-acetylcysteine tetrasulfide (NAC-S2), a supersulfide donor, attenuated the pro-inflammatory gene expression in xCT-KO PMs. Thus, activated macrophages increase cystine uptake via xCT and produce supersulfides, creating a negative feedback loop to limit excessive inflammation. Our study highlights the finely tuned regulation of macrophage inflammatory response by sulfur metabolism.

Recent advances in strategies to target the behavior of macrophages in wound healing

Chronic wounds and scar formation are widespread due to limited suitable remedies. The macrophage is a crucial regulator in wound healing, controlling the onset and termination of inflammation and regulating other processes related to wound healing. The current breakthroughs in developing new medications and drug delivery methods have enabled the accurate targeting of macrophages in oncology and rheumatic disease therapies through clinical trials. These successes have cleared the way to utilize drugs targeting macrophages in various disorders. This review thus summarizes macrophage involvement in normal and pathologic wound healing. It further details the targets available for macrophage intervention and therapeutic strategies for targeting the behavior of macrophages in tissue repair and regeneration.

How to Naturally Support the Immune System in Inflammation-Essential Oils as Immune Boosters

Efficient functionality of the immune system is needed to fight against the development of infectious diseases, including, among others, serious recurrent chronic infections. Research has shown that many modern common diseases, such as inflammatory bowel diseases and cardiovascular diseases, e.g., thromboembolism, cancer, obesity, or depression, are connected with inflammatory processes. Therefore, new, good stimulators of the immune system's response are sought. They include synthetic compounds as well as biological preparations such as lipopolysaccharides, enzymes, bacterial metabolites, and secondary metabolites of plants, demonstrating a multidirectional effect. Essential oils are characterized by many invaluable activities, including antimicrobial, antioxidant, anti-inflammatory, and immunostimulating. Essential oils may stimulate the immune system via the utilization of their constituents, such as antibodies, cytokines, and dendritic cells. Some essential oils may stimulate the proliferation of immune-competent cells, including polymorphonuclear leukocytes, macrophages, dendritic cells, natural killer cells, and B and T lymphocytes. This review is focused on the ability of essential oils to affect the immune system. It is also possible that essential oil components positively interact with recommended anti-inflammatory and antimicrobial drugs. Thus, there is a need to explore possible synergies between essential oils and their active ingredients for medical use.

Mesenchymal Stem Cell Aggregation-Released Extracellular Vesicles Induce CD31+ EMCN+ Vessels in Skin Regeneration and Improve Diabetic Wound Healing

The blood vessel system is essential for skin homeostasis and regeneration. While the heterogeneity of vascular endothelial cells has been emergingly revealed, whether a regeneration-relevant vessel subtype exists in skin remains unknown. Herein, a specialized vasculature in skin featured by simultaneous CD31 and EMCN expression contributing to the regeneration process is identified, the decline of which functionally underlies the impaired angiogenesis of diabetic nonhealing wounds. Moreover, enlightened by the developmental process that mesenchymal condensation induces angiogenesis, it is demonstrated that mesenchymal stem/stromal cell aggregates (CAs) provide an efficacious therapy to enhance regrowth of CD31+ EMCN+ vessels in diabetic wounds, which is surprisingly suppressed by pharmacological inhibition of extracellular vesicle (EV) release. It is further shown that CAs promote secretion of angiogenic protein-enriched EVs by proteomic analysis, which directly exert high efficacy in boosting CD31+ EMCN+ vessels and treating nonhealing diabetic wounds. These results add to the current knowledge on skin vasculature and help establish feasible strategies to benefit wound healing under diabetic condition.

Identification of disulfidptosis-related genes with immune infiltration in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignant primary tumor that is usually diagnosed at an advanced stage; thus, there is an urgent need for efficient and sensitive novel diagnostic markers to determine the prognosis and halt disease progression in patients with HCC. Disulfidptosis is a recently discovered form of programmed cell death, essentially an abnormal accumulation of intracellular bisulfides. Therefore, our study aimed to investigate the role of disulfidptosis-related genes (DRGs) in the pathogenesis of HCC. Based on public databases, our work demonstrates the relationship between DRG and expression, immunity, mutation/drug sensitivity, and functional enrichment in HCC. We also revealed the significant heterogeneity of HCC in different DRGs sub-clusters and in differentially expressed genes (DEGs), respectively. Subsequently, the most relevant candidate gene, SLC7A11, was screened by machine learning to further validate the significance of SLC7A11 in the clinical features, prognosis, nomogram pattern, and immune infiltration of HCC. Our study, which elucidates the potential mechanisms of DRGs and HCC, reveals that SLC7A11 can serve as a novel prognostic biomarker and provides opportunities and challenges for individualized cancer immunotherapy strategies.

Unveiling efferocytosis-related signatures through the integration of single-cell analysis and machine learning: a predictive framework for prognosis and immunotherapy response in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) represents a prominent gastrointestinal malignancy with a grim clinical outlook. In this regard, the discovery of novel early biomarkers holds substantial promise for ameliorating HCC-associated mortality. Efferocytosis, a vital immunological process, assumes a central position in the elimination of apoptotic cells. However, comprehensive investigations exploring the role of efferocytosis-related genes (EFRGs) in HCC are sparse, and their regulatory influence on HCC immunotherapy and targeted drug interventions remain poorly understood.

Methods

RNA sequencing data and clinical characteristics of HCC patients were acquired from the TCGA database. To identify prognostically significant genes in HCC, we performed the limma package and conducted univariate Cox regression analysis. Subsequently, machine learning algorithms were employed to identify hub genes. To assess the immunological landscape of different HCC subtypes, we employed the CIBERSORT algorithm. Furthermore, single-cell RNA sequencing (scRNA-seq) was utilized to investigate the expression levels of ERFGs in immune cells and to explore intercellular communication within HCC tissues. The migratory capacity of HCC cells was evaluated using CCK-8 assays, while drug sensitivity prediction reliability was determined through wound-healing assays.

Results

We have successfully identified a set of nine genes, termed EFRGs, that hold significant potential for the establishment of a hepatocellular carcinoma-specific prognostic model. Furthermore, leveraging the individual risk scores derived from this model, we were able to stratify patients into two distinct risk groups, unveiling notable disparities in terms of immune infiltration patterns and response to immunotherapy. Notably, the model's capacity to accurately predict drug responses was substantiated through comprehensive experimental investigations, encompassing wound-healing assay, and CCK8 experiments conducted on the HepG2 and Huh7 cell lines.

Conclusions

We constructed an EFRGs model that serves as valuable tools for prognostic assessment and decision-making support in the context of immunotherapy and chemotherapy.

Immunomodulatory Nanosystems: Advanced Delivery Tools for Treating Chronic Wounds

The increasingly aging society led to a rise in the prevalence of chronic wounds (CWs), posing a significant burden to public health on a global scale. One of the key features of CWs is the presence of a maladjusted immune microenvironment characterized by persistent and excessive (hyper)inflammation. A variety of immunomodulatory therapies have been proposed to address this condition. Yet, to date, current delivery systems for immunomodulatory therapy remain inadequate and lack efficiency. This highlights the need for new therapeutic delivery systems, such as nanosystems, to manage the pathological inflammatory imbalance and, ultimately, improve the treatment outcomes of CWs. While a plethora of immunomodulatory nanosystems modifying the immune microenvironment of CWs have shown promising therapeutic effects, the literature on the intersection of immunomodulatory nanosystems and CWs remains relatively scarce. Therefore, this review aims to provide a comprehensive overview of the pathogenesis and characteristics of the immune microenvironment in CWs, discuss important advancements in our understanding of CW healing, and delineate the versatility and applicability of immunomodulatory nanosystems-based therapies in the therapeutic management of CWs. In addition, we herein also shed light on the main challenges and future perspectives in this rapidly evolving research field.