Deregulated immune cell recruitment orchestrated by FOXM1 impairs human diabetic wound healing

Dual functional photocatalytic hydrogel coupled with hydrogen evolution and glucose depletion for diabetic wound therapy

Diabetic foot ulcers (DFUs), a common and serious complication of diabetes mellitus, are exacerbated by hyperglycemia-induced chronic inflammation and oxidative stress, which collectively impede the wound-healing process. Effective management requires coordinated regulation of the pathological microenvironment through localized glucose reduction, anti-inflammatory modulation, and reactive oxygen species (ROS) scavenging. This study developed an injectable functionalized hydrogel incorporating a Bi nanocrystal-decorated bismuth tungstate/hydrogen-doped titanium dioxide (Bi2WO6/H-TiO2) heterojunction with dual photocatalytic properties: glucose degradation and hydrogen evolution. Upon exposure to light, the hydrogel exploits glucose in the wound as the sacrificial substrate to simultaneously decrease local glucose concentrations and facilitate in situ hydrogen production. The released hydrogen exhibits potent antioxidant and anti-inflammatory activities, synergizing with glucose consumption to inhibit cellular apoptosis and accelerate tissue repair. A systematic evaluation revealed enhanced cell proliferation and migration in hyperglycemic in vitro models. In vivo experiments using a diabetic murine model demonstrated 50 % wound closure within 3 days, accompanied by improved angiogenesis and collagen remodeling. This photocatalytic synergistic strategy represents a clinically promising modality for diabetic wound treatment by regulating the microenvironment and restoring redox homeostasis.

Antheraea pernyi silk nanofibrils with inherent RGD motifs accelerate diabetic wound healing: A novel drug-free strategy to promote hemostasis, regulate immunity and improve re-epithelization

The chronic inflammation and matrix metalloprotease (MMP)-induced tissue degradation significantly disrupt re-epithelization and delay the healing process of diabetic wounds. To address these issues, we produced nanofibrils from Antheraea pernyi (Ap) silk fibers via a facile and green treatment of swelling and shearing. The integrin receptors on the cytomembrane could specifically bind to the Ap nanofibrils (ApNFs) due to their inherent Arg-Gly-Asp (RGD) motifs, which activated platelets to accelerate coagulation and promoted fibroblast migration, adhesion and spreading. These degradable nanofibrils served as effective competitive substrates to reduce MMP-induced tissue degradation. ApNFs and their enzymatic hydrolysates could modulate macrophage polarization due to their RGD motifs. RNA sequencing further revealed that ApNFs treatment activated the JAK2-STAT5b and PI3K-Akt signaling pathways while suppressed the NF-κB, IL-17 and TNF signaling pathways in macrophages. The full-thickness skin wound experiments confirmed that ApNFs significantly accelerated wound healing in both diabetic and non-diabetic rats. Notably, in diabetic wound, ApNFs and their enzymatic hydrolysates polarized the accumulated M1-type macrophages into M2-type, which promoted the wound to get rid of the inflammatory stage and transition to the following proliferative stage, improving the wound healing percentage on day 14 from 74.9 % to 93.2 % by facilitating collagen deposition, angiogenesis and re-epithelization. These results demonstrate that ApNFs are promising drug-free diabetic wound dressings with favorable inherent immunoregulatory properties for biomedical translation.

Mechanistic insights into Hippo-YAP pathway activation for enhanced DFU healing

With the increasing prevalence of diabetes, diabetic foot ulcers (DFUs) have become a global health challenge, significantly impacting patients' quality of life and placing a substantial burden on healthcare systems. Among various immune cell subsets, M2-polarized macrophages play a pivotal role in tissue repair and inflammation resolution. This study uses single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing to comprehensively investigate the role of the TFAP2A-LIFR-Hippo-YAP signaling axis in regulating macrophage M2 polarization and its critical function in DFU wound healing. Through scRNA-seq analysis, we identified nine major immune cell subsets in DFU samples, with macrophages emerging as key regulatory cells. In vitro experiments further confirmed that TFAP2A promotes macrophage M2 polarization (evidenced by increased expression of the M2 marker ARG1) and ameliorates endothelial dysfunction by enhancing tube formation, improving migration capacity, and upregulating relevant proteins such as VCAM-1. Moreover, TFAP2A serves as a central regulatory gene for macrophage function in DFU by upregulating LIFR expression and activating the Hippo-YAP signaling pathway, thereby inducing M2 polarization and mitigating endothelial dysfunction. Mouse model experiments further demonstrated that the TFAP2A-LIFR-Hippo-YAP signaling axis accelerates DFU wound healing through the induction of macrophage M2 polarization. This study unveils a novel immunoregulatory role of TFAP2A in DFU and provides a promising therapeutic target for the treatment of chronic diabetic wounds.NEW & NOTEWORTHY This study provides unprecedented insights into diabetic foot ulcer healing by demonstrating the novel immunoregulatory role of the TFAP2A-LIFR-Hippo-YAP signaling axis. Leveraging single-cell and bulk transcriptomics, we identify TFAP2A as a crucial regulator of macrophage M2 polarization, essential for wound healing and angiogenesis. These findings offer valuable mechanistic understanding and present TFAP2A as a promising therapeutic target for improving outcomes in chronic diabetic wounds.

Targeting m6A demethylase FTO to heal diabetic wounds with ROS-scavenging nanocolloidal hydrogels

Chronic diabetic wounds are a prevalent and severe complication of diabetes, contributing to higher rates of limb amputations and mortality. N6-methyladenosine (m6A) is a common RNA modification that has been shown to regulate tissue repair and regeneration. However, whether targeting m6A could effectively improve chronic diabetic wound healing remains largely unknown. Here, we found a significant reduction in mRNA m6A methylation levels within human diabetic foot ulcers, and the expression level of fat mass and obesity-associated protein (FTO) was significantly increased. We identified that m6A modifies the RNA of matrix Metalloproteinase 9 (MMP9), a key factor in diabetic wound healing, to regulate its expression. Importantly, we developed a ROS-scavenging nanocolloidal hydrogel loaded with an FTO inhibitor to increase the m6A level of MMP9 RNA in wounds. The hydrogel can effectively accelerate wound healing and skin appendage regeneration in streptozotocin-induced type I diabetic rats at day 14 (approximately 98 % compared to 76.98 % in the control group) and type II diabetic db/db mice at day 20 (approximately 93 % compared to 60 % in the control group). Overall, our findings indicate that targeting m6A with ROS-scavenging hydrogel loaded with FTO inhibitor may be an effective therapeutic strategy for diabetic wound healing.

Exploring the mechanism by which UCHL3 alleviates diabetic foot ulcers: FOXM1/NLRP3 inflammasome-mediated angiogenesis and endothelial cell pyroptosis

BACKGROUND

This study investigated the role of ubiquitin C-terminal hydrolase L3 (UCHL3) in regulating endothelial cell (EC) pyroptosis and angiogenesis in diabetic foot ulcers (DFUs), with a focus on FOXM1 and NLRP3 inflammasomes.

METHODS

Differentially expressed genes in DFUs were identified using the GSE134431 dataset and cross-referenced with vascular formation-related factors from GeneCard and deubiquitinases from the UbiNet 2.0 database. A rat DFU model was used to evaluate wound healing, with or without UCHL3 overexpression and FOXM1 knockdown. Histological analysis and immunohistochemistry were employed to assess tissue morphology and the expression of CD31, eNOS, UCHL3, and FOXM1. In vitro, high glucose-induced human umbilical vein ECs (HUVECs) were transfected with UCHL3 overexpression and FOXM1 knockdown constructs. Cell viability, migration, and angiogenesis were assessed.

RESULTS

UCHL3 expression was significantly reduced in DFU tissues. UCHL3 overexpression promoted wound healing in a rat model, while FOXM1 knockdown impaired wound healing and vascular formation. In HUVECs, UCHL3 overexpression enhanced cell viability, migration, and angiogenesis, accompanied by reduced NLRP3 and N-GSDMD levels. FOXM1 knockdown reversed these effects, but treatment with the NLRP3 inhibitor, MCC950, alleviated this damage.

CONCLUSION

UCHL3 enhances FOXM1 deubiquitination, inhibits NLRP3 inflammasome activation, and reduces EC pyroptosis, thereby contributing to DFU healing. UCHL3 and FOXM1 are potential therapeutic targets for DFU.

Analysis of ferroptosis-related key genes and regulatory networks in diabetic foot ulcers

BACKGROUND

Diabetic foot ulcers (DFUs) is a severe complication of diabetes. Recent evidence suggests that ferroptosis, a form of regulated necrosis, may play a significant role in the progression of DFU. However, the precise molecular mechanisms remain elusive.

OBJECTIVE

This study aims to identify ferroptosis-related genes (FRGs) and the signaling pathways involved in DFU progression by analyzing the gene expression profiles of DFU.

METHODS

Differentially expressed genes (DEGs) were identified by analyzing gene expression data from two DFU-related datasets (GSE38396, and GSE143735). FRGs were collected from both datasets and the literature. DEGs were then intersected with FRGs to identify ferroptosis-related differentially expressed genes (FRDEGs) in DFU. Functional enrichment analysis, protein-protein interaction (PPI) network analysis, receiver operating characteristic (ROC) curve analysis, and regulatory network interaction analysis (including mRNA-miRNA, mRNA-transcription factor (TF), and mRNA-drug interactions) were performed on the FRDEGs. Additionally, immune infiltration analysis was conducted using CIBERSORTx. Finally, skin tissue samples from clinical patients were collected, and the expression levels of FRDEGs in DFU samples were validated through reverse transcription quantitative real-time PCR (RT-qPCR), immunohistochemistry (IHC) and Immunofluorescence (IF), to uncover potential new targets for the diagnosis and treatment of DFU.

RESULTS

A total of 14 DFUs samples (non-healing group) and 12 control samples (healing group) were obtained in this study. We identified 276 DEGs in DFUs samples compared to controls, with 121 up-regulated and 155 down-regulated genes. By intersecting DEGs with ferroptosis-related genes, we identified 10 FRDEGs (AURKA, CTH, FBLN1, FTL, GLS2, KDM5C, MYH9, PCNA, PYCR1, and SPARC). The GO and KEGG analysis results showed that FRDEGs were mainly enriched in biological processes such as amino acid biosynthesis and tight junction pathways. Further analysis of FRDEGs identified ten hub genes closely associated with 112 TFs, 34 miRNAs, and 50 drugs or molecular compounds. Additionally, RT-qPCR validation of skin tissue samples from 8 DFU patients and 8 controls showed that AURKA were significantly up-regulated in DFU, IHC and IF analysis further demonstrated elevated AURKA protein expression in DFU samples. Moreover, AURKA was identified as a potential diagnostic marker for diabetic wound healing, with high diagnostic accuracy based on ROC curve analysis (AUC = 0.950 in the combined dataset, and AUC = 0.881 in the validation dataset). These findings highlight AURKA as a key gene involved in ferroptosis and a potential target for the diagnosis and monitoring of DFUs.

CONCLUSION

This study identified FRDEGs associated with DFUs, highlighting AURKA as a key diagnostic marker. These findings offer valuable insights into the molecular mechanisms driving DFUs and suggest potential therapeutic targets for their management.

Potential Role of CD99 Signaling Pathway in Schwann Cell Dysfunction in Diabetic Foot Ulcers Based on Single-Cell Transcriptome Analysis

Background: Schwann cell (SC) dysfunction contributes to the delayed healing of diabetic foot ulcers (DFUs). However, the underlying molecular mechanism regarding the unregulated SC function is poorly understood. Thus, we examined the single-cell transcriptome data from different DFU states focusing on SC characteristics. Methods: The single-cell RNA sequencing (scRNA-seq) data of DFU was obtained from the Gene Expression Omnibus (GEO) database, covering foot skin samples from nondiabetic patients, diabetic patients without DFU, DFU healers, and DFU nonhealers. After scRNA-seq data processing, downscaling, and cell cluster identification, cell communication analysis was performed by the CellChat package. Furthermore, we subclustered SC populations and ran the trajectory inference and pseudotime analysis to investigate the dynamic changes in SC. Finally, the significant pathways were validated with a db/db mouse wound model. Results: scRNA-seq analysis revealed different SC percentages and gene markers across the DFU groups. We identified that the CD99 signaling pathway was upregulated in the DFU nonhealer group. In the db/db mouse wound model, we observed that CD99 was highly expressed in the demyelinated area of the peripheral nerve fibers. Conclusion: Our study elucidated that the CD99 pathway activation may play a crucial role in SC dysfunction of DFU, providing insights into the peripheral glia regulation mechanism and potential therapeutic target of DFU.

Platelet-Rich Plasma-Derived Exosome-Encapsulated Hydrogels Accelerate Diabetic Wound Healing by Inhibiting Fibroblast Ferroptosis

Platelet-rich plasma-derived exosomes (PRP-Exos) have recently been considered an optimized strategy for diabetic wound treatment, yet the potential role of PRP-Exos in diabetic wound healing is still unclear. This study aims to investigate the potential mechanisms of PRP-Exos in diabetic wound healing and to utilize the hydrogel Pluronic F127 as a carrier to maintain the sustained release of encapsulated PRP-Exos. PRP-Exos were isolated from the blood of healthy individuals and characterized, followed by co-culturing with isolated diabetic human skin fibroblasts (Diabetes HSF). RNA sequencing (RNA-seq) was used to analyze the effect of PRP-Exos on the transcriptome of normal and Diabetes HSF, screening and validating the crucial mechanism and target gene. Then, a hydrogel composed of Pluronic F127 and PRP-Exos (PRP-Exos/Gel) was constructed and applied in the diabetic mouse models to evaluate the effect and mechanism. RNA-seq analysis revealed that PRP-Exos significantly upregulated the expression of FosB in Diabetes HSF. Further intervention in the expression of FosB in Diabetes HSF showed that knocking down FosB induced ferroptosis in Diabetes HSF, characterized by decreased cell viability, increased oxidative stress, and increased iron ion levels, along with downregulation of GPX4 and SLC7A11 expression, while ACSL4 expression was increased; conversely, overexpression of FosB had the opposite effect. Subsequently, adding PRP-Exos to FosB-knocked down Diabetes HSF significantly weakened the inhibitory effect of PRP-Exos on ferroptosis in diabetic fibroblasts. The synthesized PRP-Exos/Gel exhibited significant thermosensitivity and sustained release of exosomes. In animal experiments, the PRP-Exos/Gel showed significant anti-inflammatory effects, evidenced by an increased proportion of M2 macrophages and a decreased proportion of central granule cells in wound tissue, and inhibited fibroblast ferroptosis, thereby accelerating wound healing. Overall, the constructed PRP-Exos/Gel displays a continuous release of exosomes and promotes diabetic wound healing by suppressing inflammatory responses and fibroblast ferroptosis, which provides new insights and methods for the treatment of diabetic wounds.

Post-transcriptional regulation of diabetic wound healing by junctional adhesion molecule A/miR-106b axis

BACKGROUND

Despite advancements in molecular science and biomaterial technology, the mechanisms underlying the impaired healing of diabetic wounds remain unclear. In this study, we investigated the post-transcriptional regulation of diabetic wound healing using JAM-A.

METHODS

Mouse wound models, hematoxylin and eosin staining analysis, and scratch wound assays were used to investigate the effects of JAM-A 3'-UTR on the re-epithelialization of diabetic wounds, whereas RNA pulldown, microRNA-seq, and bioinformatics analyses were performed to identify key miRNA players and predict their target genes. In situ hybridization, immunohistochemistry, western blotting, and polymerase chain reaction (PCR) were used to confirm the alternative splicing of JAM-A 3'-UTR in diabetic conditions. CCK-8 proliferation assays, scratch wound assays, PCR, western blotting, and dual-luciferase assays were performed to study the changes in cell proliferation and migration induced by miR-106b-5p modification and confirm the target gene.

RESULTS

JAM-A 3'-UTR accelerated re-epithelialization in diabetic mouse wounds. Shortened splicing was found in the 3'-UTR of JAM-A under diabetic conditions, leading to the excessive release of miR-106b-5p while the promoter of miR-106b was activated. Furthermore, upregulated miR-106b-5p over-activated cell proliferation and inhibited cell migration in diabetic wound keratinocytes by suppressing the target gene PTEN/TIAM1 and regulating the AKT and RAC1 pathways, thereby impairing wound re-epithelialization.

CONCLUSIONS

We identified alternative splicing of JAM-A 3'-UTR in diabetic conditions, which caused the excessive release of miR-106b. Upregulation of miR-106b reduced the expression of its target genes, PTEN and TIAM1, which led to hyperactive proliferation and impaired migration of keratinocytes, thereby dysregulating wound re-epithelialization.

Deciphering the Dysregulating IGF-1-SP1-CD248 Pathway in Fibroblast Functionality during Diabetic Wound Healing

Reduced fibroblast activity is a critical factor in the progression of diabetic ulcers. CD248, a transmembrane glycoprotein prominently expressed in activated fibroblasts, plays a pivotal role in wound healing. However, the role of CD248 in diabetic wound healing and the CD248 regulatory pathway remains largely unexplored. Our study shows that CD248 expression is significantly reduced in skin wounds from both patients and mice with diabetes. Single-cell transcriptome data analyses reveal a marked reduction of CD248-enriched secretory-reticular fibroblasts in diabetic wounds. We identify IGF-1 as a key regulator of CD248 expression through the protein kinase B/mTOR signaling pathway and the SP1 transcription factor. Overexpression of CD248 enhances fibroblast motility, elucidating the under-representation of CD248-enriched fibroblasts in diabetic wounds. Immunohistochemical staining of diabetic wound samples further confirms low SP1 expression and fewer CD248-positive secretory-reticular fibroblasts. Further investigation reveals that elevated TNFα levels in diabetic environment promotes IGF-1 resistance, and inhibiting IGF-1 induced CD248 expression. In summary, our findings underscore the critical role of the IGF1-SP1-CD248 axis in activating reticular fibroblasts during wound-healing processes. Targeting this axis in fibroblasts could help develop a therapeutic regimen for diabetic ulcers.

Dihydroartemisinin Targets the NFIC/FBN1 Cascade to Enhance Wound Healing in Chronic Skin Ulcer by Inhibiting Fibroblast Ferroptosis

Dysfunction of fibroblasts contributes to a pathological state to delay wound repair in chronic skin ulcer (CSU). Dihydroartemisinin (DHA), a derivative of artemisinin, has a therapeutic potential in diverse diseases owing to multiple pharmacological effects. However, no attempt was made to evaluate the function of DHA in CSU. Human dermal fibroblasts were isolated from the peripheral ulcerative tissues in CSU patients (uHFBs) and normal skins (nHFBs). Cell migration, proliferation, apoptosis, and ability were detected. Ferroptosis was evaluated by detecting Fe2+, iron and ROS contents. Immunoblot and quantitative PCR analyses were performed to quantify expression. The NFIC/FBN1 binding relationship was verified by luciferase reporter assay. The CSU mouse model was established, and histology and Masson's staining was used to analyze DHA efficacy. DHA increased NFIC expression in uHFBs. DHA accelerated cell proliferation and migration and impeded ferroptosis in uHFBs, which could be partially counteracted by NFIC reduction. Mechanistically, NFIC transcriptionally elevated FBN1 expression, and DHA increased FBN1 expression by NFIC. NFIC increase enhanced uHFB proliferation and migration and suppressed ferroptosis, which could be abrogated by FBN1 downregulation. Moreover, DHA improved wound repair in CSU mice by upregulating NFIC and FBN1. Additionally, NFIC and FBN1 were underexpressed in uHFBs versus nHFBs. Our findings indicate that DHA has the efficacy to improve wound repair in CSU mice and upgrades skin fibroblast function via the NFIC/FBN1 cascade. DHA may be a novel drug for CSU treatment.

Beta-boswellic acid facilitates diabetic wound healing by targeting STAT3 and inhibiting ferroptosis in fibroblasts

Objective

Diabetic wounds are a severe complication of diabetes, with persistently high incidence and mortality rates, often leading to severe clinical outcomes such as amputation. Beta-boswellic acid (β-BA) is a plant-derived pentacyclic triterpene with activities of inflammatory control and ferroptosis regulation. However, the protective effect of β-BA on DW has not been described.

Method

We employed network analysis approaches and molecular docking to predict the potential targets and pathways of β-BA in the treatment of diabetic wounds (DW). Both in vitro and in vivo models were established, including high-glucose-induced fibroblast models and diabetic rat wound models. The effects of β-BA on diabetic wounds were investigated through CCK-8 assay, wound healing assay, immunofluorescence staining, western blotting, fluorescent probe analysis, gross observation, and histopathological experiments.

Result

In this study, we predicted potential targets for β-BA using public databases and identified 29 key genes, with STAT3 being the most significant. GO analysis revealed that these targets are involved in biological processes closely related to ferroptosis, such as regulation of inflammatory response and lipid metabolism. Our results showed that HG induced ferroptosis in HSFs, as evidenced by decreased cell viability, altered GSH/MDA, Fe2+, and ROS levels, and changes in the expression of ferroptosis-related genes ACSL4 and GPX4. Notably, treatment with the ferroptosis inhibitor Ferr-1 partly reversed these effects. CCK-8 assays showed that β-BA improved HSFs viability in a concentration-dependent manner. Immunofluoresc-ence staining and further biochemical analyses demonstrated that β-BA reduced Fe2+ and lipid peroxide levels, prevented oxidative damage, and improved cell migration ability impaired by HG. Western blot analysis confirmed that β-BA reversed the changes in ACSL4 and GPX4 expression induced by HG. Molecular docking validated the potential binding between β-BA and STAT3. Western blot analysis revealed that β-BA increased the level of phosphorylated STAT3 in HSFs. Introducing a STAT3 inhibitor diminished the beneficial effects of β-BA on HG-induced cell dysfunction and suppressed its protective effect against ferroptosis. Finally, we assessed the efficacy of β-BA in the treatment of diabetic wounds in rats. BA administration accelerated wound closure, reduced inflammatory cell infiltration, improved granulation tissue arrangement, and increased collagen deposition. Immunohistochemical staining showed that BA upregulated the number of STAT3-positive cells and upregulated the number of GPX4-positive cells in the wounds, suggesting that BA can inhibit ferroptosis and accelerate wound healing in diabetic rats.

Conclusion

Our findings suggested that β-BA may exert its therapeutic effects on diabetic wounds by targeting STAT3 and inhibiting ferroptosis.

Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: a narrative review

Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.

Exudate Management, Facile Detachment, and Immunometabolism Regulation for Wound Healing Using Breathable Dressings

Developing breathable dressings with multifunctional properties (such as exudate management, easy removal, and immunometabolism regulation) presents significant challenges in wound healing. This study employs the Hofmeister effect to prepare a sodium citrate-cross-linked cryogel (CA-CS) with versatile functions, including porous and loose structures, rapid shape recovery ability, superior fatigue resistance behavior, and outstanding biocompatibility capabilities. The CA-CS cryogels demonstrated strong anti-inflammatory properties by reversing the lipopolysaccharides-induced M1 macrophages and increasing M2 macrophage percentages in vitro. Additionally, these breathable CA-CS cryogels exhibited superior hemostatic activity in vivo. The easily detachable CA-CS cryogels enhanced nutrient exchange, promoted exudate absorption, regulated immune response, and induced metabolic reprogramming, thereby supporting skin regeneration and hair follicle formation in a full-thickness skin defect mouse model. We expect that these CA-CS cryogels will drive the development of next-generation dressings for effective wound regeneration in clinical practice.

Paeonol regulates the DDIT4-mTOR signaling pathway in macrophages to promote diabetic wound healing

BACKGROUND

Diabetic foot ulcers are a common complication in people with diabetes, and patients with severe disease are at risk of amputation. Current studies have found that one of the reasons for the difficulty in healing diabetic foot ulcers is the Abnormal polarization of the M1/M2 phenotype of macrophages, which leads to a prolonged inflammatory period of the wound. The aim of this study was to investigate whether paeonol can promote the polarization of macrophages towards the M2 type and whether M2 type macrophages can regulate the DDIT4-mTOR signaling pathway and slow down the inflammatory response of diabetic foot ulcers.

METHODS

C57BL/6 mice were used to establish an animal model of diabetic foot ulcers and the effect of paeonol on wound healing was investigated. The effects of paeonol on wound healing of foot ulcer in diabetic mice were evaluated using histological staining and immunohistochemistry. The molecular mechanism of refractory healing of foot ulcers was speculated through network pharmacology. The effects of Paeonol on phenotypic polarization of macrophages and the mechanism of inhibiting inflammation were studied by q-PCR, ELISA, immunofluorescence and Western.

RESULTS

Paeonol can effectively promote wound healing in diabetic mice. HE staining showed that paeonol could improve the inflammatory infiltration in the ulcer wound of diabetic mice; Masson trichromatic staining showed that paeonol could increase the increase of muscle fibers and collagen in the wound tissue of diabetic mice; immunofluorescence results showed that paeonol could increase the angiogenesis in the wound tissue of diabetic mice. Network pharmacological analysis showed that the molecular mechanism of paeonol in treating diabetic wound healing may be through DDIT4-mTOR signaling pathway. q-PCR, ELISA, immunofluorescence and Western blot showed that paeonol could reduce the expression of the signature protein CD86 and inflammatory factors in M1 macrophages, and promote the phenotypic polarization of M2 macrophages, which is the mechanism of inhibiting inflammation by activating DDIT4-mTOR signaling pathway.

CONCLUSION

Paeonol can promote the polarization of macrophages towards M2 type, reduce inflammatory response and accelerate wound surface healing through DDIT4-mTOR signaling pathway, providing a new therapeutic strategy for the treatment of diabetic foot ulcers.

Self-Healing Hydrogel Dressing with Solubilized Flavonoids for Whole Layer Regeneration of Diabetic Wound

Hydrogels are soft, tissue-like materials that have great potential as wound dressings. However, most hydrogels are unsatisfactory in achieving whole-layer regeneration of diabetic wounds due to the complex pathological microenvironment and irregular wound shapes. Here, a glucose-responsive and self-adaptive phenylboronic acid (PBA) hydrogel solubilized strong antioxidant flavonoids (Gel-Flavonoids) is developed via dynamic borate bonds. The Gel-Flavonoids system can spontaneously confirm to the irregular wound shape and release flavonoids in a high-glucose microenvironment to effectively eliminate reactive oxygen species (ROS). The optimized Gel-Flavonoids demonstrate remarkable efficacy in inhibiting inflammation and activating fibroblasts and endothelial cells through CD36-activated lipid metabolism in macrophages and is significantly superior to commercial dressings (3M) in healing rate (> 93%, 14 days) and whole-layer regeneration effect. This study obtained a multidimensional Gel-Flavonoids system to effectively repair diabetic wounds, and reveal the underlying therapeutic mechanisms, offering a promising insight to guide the development of medical materials to treat diabetic wounds.

Self-healing Ppy-hydrogel promotes diabetic skin wound healing through enhanced sterilization and macrophage orchestration triggered by NIR

Non-healing diabetic foot ulcers are the knotty public health issue due to the uncontrolled bacterial infection, prolonged inflammation, and inferior vessel remodeling. In this work, polypyrrole (Ppy) was added into the hybrid hydrogel containing polyvinyl alcohol (PVA), polyethylene glycol (PEG), and hyaluronan (HA) to acquire superior mechanism and photothermal ability. The Ppy composited hybrid hydrogel could effectively kill bacteria through accumulating heat on the hydrogel surface. RNA-Seq analysis shows that the heat accumulation could enhance phagosome of macrophage and M1 activation, which further accelerate bacteria clearance. Benefitting from the bacteria clearance, macrophage could transform its phenotype to M2 in Ppy composited hybrid hydrogel group with near infrared light (NIR) stimulation. The related genes expression in keratinization, keratinocyte differentiation, and establishment of the skin barrier in the skin were up-regulated and collagen and vascular endothelial growth factor (VEGF) expression level are also enhanced. In summary, Ppy composited hybrid hydrogel could effectively solve the issues of infection and poor wound healing in diabetic foot ulcers, making it an ideal candidate dressing for the treatment of chronic wounds.

Photothermally Enhanced Cascaded Nanozyme-Functionalized Black Phosphorus Nanosheets for Targeted Treatment of Infected Diabetic Wounds

Due to the limitations of H2O2 under physiological conditions and defective activity, nanozyme-catalyzed therapy for infected diabetic wound healing is still a huge challenge. Here, this work designs a novel multifunctional hybrid glucose oxidase (GOx)-CeO2@black phosphorus (BP)/Apt nanosheet that features GOx and CeO2 dual enzyme loading with photothermal enhancement effect and targeting ability for the treatment of infected wounds in type II diabetic mice. Combined with the photothermal properties of the BP nanosheets, the cascade nanozyme effect of GOx and CeO2 is extremely enhanced. The synergistic effect of peroxidase activity and photothermal therapy with targeting aptamer allows for overcoming the catalytic defects of nanozyme and significantly improving in vitro bacterial inhibition rate with 99.9% and 97.8% for Staphylococcus aureus and Escherichia coli, respectively, as well as enhancing in vivo antibacterial performance with the lowest wound remained (0.05%), reduction of infiltration inflammatory cells, and excellent biocompatibility. Overall, this work builds a nanodelivery system with a powerful therapeutic approach, incorporating self-supplying H2O2 synergistic photothermal and real-time wound monitoring effect, which holds profound potential as a clinical treatment for infected diabetic wounds.

Dual-Action flavonol carbonized polymer dots spray: Accelerating burn wound recovery through immune responses modulation and EMT induction

Effective immune homeostasis modulation and re-epithelialization promotion are crucial for accelerating burn wound healing. Cell migration is fundamental to re-epithelialization, with epithelial-mesenchymal transition (EMT) as a key mechanism. A sustained inflammatory environment or impaired macrophage transition to M2 phenotype can hinder pro-resolving cytokine activation, further delaying the recruitment, migration, and re-epithelialization of epidermal cells to the injury site, ultimately compromising wound healing. Herein, the bioactive flavonol quercetin is transformed into pharmacologically active carbonized polymer dots (Qu-CDs) spray with high water dispersibility, permeability and biocompatibility for full-thickness skin burns treatment. Qu-CDs spray can efficiently initiate macrophage reprogramming and promote the transition of macrophages from M1 to M2 phenotype, modulating immune responses and facilitating the shift from the inflammatory phase to re-epithelialization. Additionally, Qu-CDs spray can promote cell migration and re-epithelialization of wound edge epithelial cells by inducing an EMT process without growth factors, further accelerating the reconstruction of the normal epidermal barrier. Mechanistically, Qu-CDs spray activates the smad1/5 signaling pathway for promoting the EMT phenotype of wound edge epithelial cells. Overall, this study facilitates the construction of novel spray dosage form of pharmacologically active carbonized polymer dots with desired bioactivities for effective wound healing.

A multiple-crosslinked injectable hydrogel for modulating tissue microenvironment and accelerating infected diabetic wound repair

Elevated oxidative stress and inflammation, bacterial infections, and vascular impairment undoubtedly impede the normal diabetic wound healing process, which has encouraged the development of high-performance dressings for wound management. Herein, a new type of multiple-crosslinked injectable hydrogel, GCP, was developed via the radical polymerization of propenyl groups and the formation of copper‒polyphenol coordination bonds and Schiff base bonds. The copper‒polyphenol coordination and Schiff base bonds in the GCP hydrogel were disrupted in the acidic microenvironment of diabetic wound, resulting in the release of copper ions and protocatechualdehyde (PA) to scavenge reactive oxygen species (ROS), promote angiogenesis and cell migration, and exert antibacterial and anti-inflammatory activities via the CuPA complexes. Consequently, markedly accelerated infected diabetic wounds healing was achieved through this tissue microenvironment remodeling strategy. Moreover, the underlying mechanism of the antibacterial properties was investigated by 16S rRNA sequencing. The results indicated that the CuPA complexes can clearly inhibit the growth and reproduction of S. aureus by downregulating specific genes associated with ABC transporters, hindering bacterial protein synthesis, and enhancing oxidoreductase activity. This innovative hydrogel platform for wound management may inspire new methods for the preparation of high-performance biomedical materials and the treatment of other clinical diseases.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Single-cell RNA sequencing reveals the impaired epidermal differentiation and pathological microenvironment in diabetic foot ulcer

Background

Diabetic foot ulcer (DFU) is one of the most common and complex complications of diabetes, but the underlying pathophysiology remains unclear. Single-cell RNA sequencing (scRNA-seq) has been conducted to explore novel cell types or molecular profiles of DFU from various perspectives. This study aimed to comprehensively analyze the potential mechanisms underlying impaired re-epithelization of DFU in a single-cell perspective.

Methods

We conducted scRNA-seq on tissues from human normal skin, acute wound, and DFU to investigate the potential mechanisms underlying impaired epidermal differentiation and the pathological microenvironment. Pseudo-time and lineage inference analyses revealed the distinct states and transition trajectories of epidermal cells under different conditions. Transcription factor analysis revealed the potential regulatory mechanism of key subtypes of keratinocytes. Cell-cell interaction analysis revealed the regulatory network between the proinflammatory microenvironment and epidermal cells. Laser-capture microscopy coupled with RNA sequencing (LCM-seq) and multiplex immunohistochemistry were used to validate the expression and location of key subtypes of keratinocytes.

Results

Our research provided a comprehensive map of the phenotypic and dynamic changes that occur during epidermal differentiation, alongside the corresponding regulatory networks in DFU. Importantly, we identified two subtypes of keratinocytes: basal cells (BC-2) and diabetes-associated keratinocytes (DAK) that might play crucial roles in the impairment of epidermal homeostasis. BC-2 and DAK showed a marked increase in DFU, with an inactive state and insufficient motivation for epidermal differentiation. BC-2 was involved in the cellular response and apoptosis processes, with high expression of TXNIP, IFITM1, and IL1R2. Additionally, the pro-differentiation transcription factors were downregulated in BC-2 in DFU, indicating that the differentiation process might be inhibited in BC-2 in DFU. DAK was associated with cellular glucose homeostasis. Furthermore, increased CCL2 + CXCL2+ fibroblasts, VWA1+ vascular endothelial cells, and GZMA+CD8+ T cells were detected in DFU. These changes in the wound microenvironment could regulate the fate of epidermal cells through the TNFSF12-TNFRSF12A, IFNG-IFNGR1/2, and IL-1B-IL1R2 pathways, which might result in persistent inflammation and impaired epidermal differentiation in DFU.

Conclusions

Our findings offer novel insights into the pathophysiology of DFU and present potential therapeutic targets that could improve wound care and treatment outcomes for DFU patients.

Electrospinning strategies targeting fibroblast for wound healing of diabetic foot ulcers

The high incidence and prevalence of diabetic foot ulcers (DFUs) present a substantial clinical and economic burden, necessitating innovative therapeutic approaches. Fibroblasts, characterized by their intrinsic cellular plasticity and multifunctional capabilities, play key roles in the pathophysiological processes underlying DFUs. Hyperglycemic conditions lead to a cascade of biochemical alterations that culminate in the dysregulation of fibroblast phenotype and function, which is the primary cause of impaired wound healing in DFUs. Biomaterials, particularly those engineered at the nanoscale, hold significant promise for enhancing DFU treatment outcomes. Electrospun nanofiber scaffolds, with their structural and compositional similarities to the natural extracellular matrix, serve as an effective substrate for fibroblast adhesion, proliferation, and migration. This review comprehensively summarizes the biological behavior of fibroblasts in DFUs and the mechanism mediating wound healing. At the same time, the mechanism of biological materials, especially electrospun nanofiber scaffolds, to improve the therapeutic effect by regulating the activity of fibroblasts was also discussed. By highlighting the latest advancements and clinical applications, we aim to provide a clear perspective on the future direction of DFU treatment strategies centered on fibroblast-targeted therapies.

The emerging role of nanoscaffolds in chronic diabetic wound healing: a new horizon for advanced therapeutics

Non-healing or chronic wounds in extremities that lead to amputations in patients with Type II diabetes (hyperglycemia) are among the most serious and common health problems in the modern world. Over the past decade, more efficient solutions for diabetic ulcers have been developed. Nanofibers and/or composite materials capable of drug delivery, moisture control, and antibacterial effectiveness are increasingly utilized in the formulation of wound dressings, with a particular focus on the biofunctionalization of polymeric and hydrogel materials. Natural products, including plant extracts, honey, antibacterial agents, nanozymes, and metal nanoparticles, are now commonly and effectively implemented to enhance the functionality of wound dressings. Due to the complicated and dysfunctional physiological structure of the chronic wound sites in the extremities of diabetic patients, formulated nanoscaffold or hydrogel components are becoming more intricate and versatile. This study aimed to investigate the development of wound dressing materials over the years while demonstrating their progressively enhanced complexity in effectively targeting, treating, and managing chronic wounds. The mechanisms of action and bio-functionality of wound dressing technologies were elucidated based on findings from 290 studies conducted over the last decade. A notable observation that emerged from these studies is the evolution of wound dressing development technology, which has led to significant advancements in the operational range of smart systems. These include, but are not limited to, self-healing, self-oxygenation, and adaptable mimicry of human tissue.

Single-Cell Analysis of Debrided Diabetic Foot Ulcers Reveals Dysregulated Wound Healing Environment in Non-Hispanic Black Patients

Diabetic foot ulcer is a critical complication of diabetes, but the wound microenvironment and its healing process are not completely understood. In this study, we optimized single-cell profiling from sharp debrided ulcers. Our findings demonstrate that healing diabetic foot ulcers were significantly enriched with distinct fibroblasts-expressing genes related to inflammation (CHI3L1, IL6) and extracellular matrix remodeling (ASPN), validating our previous studies on surgically resected ulcers. The race-focused analysis depicted lower expression of key healing-associated genes such as CHIL3L1, matrix metalloproteinase 11 gene MMP11, and SFRP4 in fibroblasts of non-Hispanic Black patients than in those of White patients. In cellular communication analysis, healing-enriched fibroblasts of non-Hispanic Black patients exhibited upregulation of signaling pathways such as WNT, whereas those of White patients showed insulin-like GF and Midkine pathways upregulation. Our findings advocate race as a risk marker of diabetic foot ulcer outcomes, likely reflecting underlying disparities in environmental exposures and access to care that profoundly influence healing markers. Using sharp debrided tissues for single-cell assays, this study highlights the need for in-depth investigations into dysregulated wound healing microenvironments of under-represented racial groups.

Gentiopicroside targeting AKT1 activates HIF-1α/VEGF axis promoting diabetic ulcer wound healing

Backgound

Gentiopicroside (GSP) have been proven to accelerate the healing of diabetic ulcers (DU), but the underlying molecular mechanisms remain unclear. This study aims to explore the mechanism by which GSP accelerates the healing of DU.

Method

The targets of GSP were firstly predicted using the SuperPred, SwissTargetPrediction, and Pharmmapper databases; DU-related transcriptome data were obtained from the GEO database, including GSE147890, GSE68183, and GSE199939; differential expression analysis was conducted using the Limma package, and DU-related targets were identified after summarization and de-duplication. Then, Potential targets for GSP treatment of DU were screened by Venn analysis; core targets for GSP treatment of DU were selected by constructing a protein-protein interaction (PPI) network; the mechanism of GSP treatment of DU was predicted by GO and KEGG enrichment analysis. Finally, the target binding of GSP to core targets was evaluated by molecular docking and CETSA assay, and in vitro experiments were conducted using L929 cells to validate the findings.

Result

A total of 538 targets of GSP and 10795 DU-related targets were predicted; Venn analysis identified 215 potential targets for GSP to accelerate DU wound healing; PPI network analysis suggested that AKT1 may be core targets for GSP treatment of DU; GO and KEGG enrichment analysis showed that pathways such as HIF-1 and VEGF are closely related to the treatment of DU with GSP, and it also participates in the regulation of various biological processes such as small molecule catabolism and leukocyte migration to exert its therapeutic effect on DU. Molecular docking and CETSA detection indicated that GSP can target bind to AKT1. The experimental results confirmed that GSP can significantly promote the proliferation and migration of L929 cells. Westen Blot results showed that GSP can accelerate DU wound healing via AKT1/HIF-1α/VEGF axis.

Conclusion

GSP target binding to AKT1 accelerates DU wound healing via the regulation of HIF-1α/VEGF axis.

The effects of immune cell phenotypes and plasma metabolomes on diabetic foot ulcer: a Mendelian randomization study and mediation analysis

This study investigates the causal relationships between plasma metabolites, immune cell phenotypes, and diabetic foot ulcer (DFU). A Mendelian randomization (MR) study was conducted, which included 731 immune cell phenotypes, 1400 metabolites, and DFU. The primary analytical approach was the inverse variance-weighted method. Sensitivity analyses were performed to assess heterogeneity and pleiotropy, and MR analyses in the reverse direction were conducted to examine the possibility of reverse causation. In addition, a mediation analysis was performed to reveal how metabolites mediate the impact of immune cells on DFU. Through MR, reverse MR and sensitivity analysis, the casualty was found in 17 immune cell phenotypes and 18 metabolites. A total of 15 mediating relationships were identified through mediation analysis, including 9 metabolites and 10 immune cell phenotypes. Among them, the highest mediation proportion was citrulline levels mediating CD24+ CD27+ AC (absolute count, B cell panel) to DFU, with a proportion of 11.60%. In conclusion, the study identified causal relationships between 10 immune cell phenotypes mediated by 9 metabolites. These discoveries offered fresh perspectives on the processes behind DFU and laid the groundwork for subsequent studies to create specific treatments for DFU.

Inflammatory memory-activated biomimetic nanovesicles regulate neutrophil plasticity and metabolic reprogramming for rapid diabetic wound healing via targeting miR-193a-5p/TLR4/JNK/P38 MAPK pathways

Diabetic wound therapy faces significant challenges due to the complexity of the wound microenvironment, especially dysregulated immune cell responses and persistent pro-inflammatory sate. Targeting immune cells to reverse pathological wound conditions has increasingly become a promising strategy to promote diabetic wound healing. It has been reported that prolonged memory to acute inflammation sensitizes epidermal stem cells (EpSCs) to tissue damage. The increasing importance of interactions between immune cells and tissue stem cells has raised interest in the potential of EpSCs to induce inflammatory adaptations in diabetic wounds, and meanwhile, the inflammation memory patterns also provide new insight in EpSCs for tissue repair. Here, bioinspired cell-derived mimetic nanovesicles (MNVs) were obtained from inflammation memory-activated EpSCs. LPS treatment could trigger acute inflammation response and activate inflammation memory. MNVs derived from LPS-pretreated EpSCs (LEM) can effectively promote diabetic wound healing by manipulating crucial neutrophil regulatory mechanisms. The in vitro and in vivo studies demonstrated that LEM could stimulate neutrophil mitochondrial metabolic reprogramming, overcome phenotypic switching deficiency of neutrophils, and skew neutrophils toward N2 anti-inflammatory phenotype via regulating miR-193a-5p/TLR4/ JNK/P38 MAPK pathways in diabetic models. Our findings highlighted the great potential of inflammation memory in EpSCs, and also provided an alternative for diabetic wound treatment.

Out of this World: Wound Healing on Earth and in Space

Impaired wound healing is a significant concern for humans in space, where the unique microgravity environment poses challenges to the natural healing processes of the body. Similar to chronic wounds on earth, such as diabetic foot ulcers and venous leg ulcers, wounds inflicted in space exhibit delayed or impaired healing responses. These wounds share common features, including dysregulated cellular signaling, altered cytokine profiles, and impaired tissue regeneration. Little is known about the mechanisms underlying wound healing under microgravity. In this review, we focused on exploring the parallels between wound healing in space and chronic wounds on earth as a fundamental approach for developing effective countermeasures to promote healing and mitigate associated health risks during long-space missions.

Hydrogel-based therapies for diabetic foot ulcers: recent developments and clinical implications

The diabetic foot ulcer is among the most serious diabetes-associated complications, with a long disease course considerably increasing the pain and economic burden of patients, leading to amputation and even death. High blood sugar is characteristic of diabetic foot ulcers, with insufficient blood supply, oxidative stress disorder, and high-risk bacterial infection posing great challenges for disease treatment. Advances in hydrogel dressings have shown potential for the management of diabetic foot ulcers involving multisystem lesions. This study comprehensively reviews the pathogenesis of diabetic foot ulcers and advances in hydrogel dressings in treating diabetic foot ulcers, providing innovative perspectives for assessing the nursing care requirements and associated clinical applications.

Inhibition of microRNA-139-5p Improves Fibroblasts Viability and Enhances Wound Repair in Diabetic Rats Through AP-1 (c-Fos/c-Jun)

Introductions

Diabetic foot ulcers (DFU) are notoriously difficult to heal, however, its underlying molecular mechanisms are unknown. MicroRNA-139-5p participates in various biological processes, including cancer and vascular endothelial injury, while its role in diabetic wound healing has not been reported.

Methods

Sprague-Dawley (SD) rats were intraperitoneally injected with streptozotocin and a 1.0 cm full-layer dorsal skin wound was made to establish a diabetic wound model. On days 1, 4, 7, and 10 after the wound was made, a solution containing microRNA-139-5p antagomir or control was injected along the dorsal edge of the wound. Wound healing was analyzed using Image J, histological analysis and molecular analysis. Skin tissues from 4 diabetic and 4 matched non-diabetic ulcer patients were obtained to detect microRNA-139-5p expression. In vitro, human skin fibroblasts were transfected with microRNA-139-5p inhibitors/mimics, the function of the fibroblasts was evaluated by CCK-8 assay and scratch assay, and AP-1 (c-Fos/c-Jun) was detected.

Results

Obviously elevated microRNA-139-5p expression was detected in the wound tissue of the rats with diabetes and patients with DFUs, and the microRNA-139-5p antagonist-treated diabetic wounds had faster healing rates. The pace of diabetic wound re-epithelialization and angiogenesis was accelerated, and the expression of AP-1 family members (c-Fos/c-Jun), and VEGF, PDGF was upregulated in the wound tissue of diabetic rats treated with topical microRNA-139-5p antagomir. In vitro, the expression of microRNA-139-5p was up-regulated in human skin fibroblasts induced by high glucose treatment, while the function of the cell proliferation and migration was promoted and the level of AP-1 (c-Fos/c-Jun) was increased after transfected with the microRNA-139-5p inhibitor, and vice versa. Our study further verified that microRNA-139-5p regulated the migration of human skin fibroblasts by modulating c-Fos.

Conclusion

Inhibiting microRNA-139-5p improves fibroblasts viability and promotes diabetic wound healing, suggesting that this may be a therapeutic strategy for diabetic foot ulcer.

PKM2-mediated collagen XVII expression is critical for wound repair

Chronic wounds have emerged as a tough clinical challenge. An improved understanding of wound-healing mechanisms is paramount. Collagen XVII (COL17), a pivotal constituent of hemidesmosomes, holds considerable promise for regulating epidermal cell adhesion to the basement membrane as well as for epidermal cell motility and self-renewal of epidermal stem cells. However, the precise role of COL17 in wound repair remains elusive, and the upstream regulatory mechanisms involved have not been fully elucidated. In this study, we delineated the temporal and spatial expression patterns of COL17 at the epidermal wound edge. Subsequently, we investigated the indispensable role of COL17 in keratinocyte activation and reepithelialization during wound healing, demonstrating the restoration of the normal repair process by COL17 overexpression in diabetic wounds. Notably, we identified a key transcriptional signaling pathway for COL17, wherein pyruvate kinase isozyme M2 (PKM2) promotes phosphorylation of STAT3, leading to its activation and subsequent induction of COL17 expression upon injury. Ultimately, by manipulating this pathway using the PKM2 nuclear translocator SAICAR, we revealed a promising therapeutic strategy for enhancing the healing of chronic wounds.

The role of multiomics in revealing the mechanism of skin repair and regeneration

Skin repair and regeneration are crucial processes in restoring the integrity of the skin after injury, with significant implications for medical treatments and plastic surgery. Multiomics, an integrated approach combining genomics, transcriptomics, proteomics, and metabolomics, offers unprecedented insights into the complex molecular and cellular mechanisms involved in skin healing. This review explores the transformative role of multiomics in elucidating the mechanisms of skin repair and regeneration. While genomic studies identify the genetic basis of wound healing, transcriptomics and proteomics uncover the dynamic changes in gene and protein expression, and metabolomics provides a snapshot of metabolic alterations associated with wound healing. Integrative multiomics studies can also identify novel biomarkers and therapeutic targets for skin regeneration. Despite the technical and biological challenges, the future of multiomics in skin research holds great promise for advancing personalized medicine and improving wound healing strategies. Through interdisciplinary collaboration, multiomics has the potential to revolutionize our understanding of skin repair, paving the way for innovative treatments in plastic surgery and beyond.

The analysis of gene co-expression network and immune infiltration revealed biomarkers between triple-negative and non-triple negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a heterogeneous disease with a worse prognosis. Despite ongoing efforts, existing therapeutic approaches show limited success in improving early recurrence and survival outcomes for TNBC patients. Therefore, there is an urgent need to discover novel and targeted therapeutic strategies, particularly those focusing on the immune infiltrate in TNBC, to enhance diagnosis and prognosis for affected individuals.

Methods

The gene co-expression network and gene ontology analyses were used to identify the differential modules and their functions based on the GEO dataset of GSE76275. The Weighted Gene Co-Expression Network Analysis (WGCNA) was used to describe the correlation patterns among genes across multiple samples. Subsequently, we identified key genes in TNBC by assessing genes with an absolute correlation coefficient greater than 0.80 within the eigengene of the enriched module that were significantly associated with breast cancer subtypes. The diagnostic potential of these key genes was evaluated using receiver operating characteristic (ROC) curve analysis with three-fold cross-validation. Furthermore, to gain insights into the prognostic implications of these key genes, we performed relapse-free survival (RFS) analysis using the Kaplan-Meier plotter online tool. CIBERSORT analysis was used to characterize the composition of immune cells within complex tissues based on gene expression data, typically derived from bulk RNA sequencing or microarray datasets. Therefore, we explored the immune microenvironment differences between TNBC and non-TNBC by leveraging the CIBERSORT algorithm. This enabled us to estimate the immune cell compositions in the breast cancer tissue of the two subtypes. Lastly, we identified key transcription factors involved in macrophage infiltration and polarization in breast cancer using transcription factor enrichment analysis integrated with orthogonal omics.

Results

The gene co-expression network and gene ontology analyses revealed 19 modules identified using the dataset GSE76275. Of these, modules 5, 11, and 12 showed significant differences between in breast cancer tissue between TNBC and non-TNBC. Notably, module 11 showed significant enrichment in the WNT signaling pathway, while module 12 demonstrated enrichment in lipid/fatty acid metabolism pathways. Subsequently, we identified SHC4/KCNK5 and ABCC11/ABCA12 as key genes in module 11 and module 12, respectively. These key genes proved to be crucial in accurately distinguishing between TNBC and non-TNBC, as evidenced by the promising average AUC value of 0.963 obtained from the logistic regression model based on their combinations. Furthermore, we found compelling evidence indicating the prognostic significance of three key genes, KCNK5, ABCC11, and ABCA12, in TNBC. Finally, we also identified the immune cell compositions in breast cancer tissue between TNBC and non-TNBC. Our findings revealed a notable increase in M0 and M1 macrophages in TNBC compared to non-TNBC, while M2 macrophages exhibited a significant reduction in TNBC. Particularly intriguing discovery emerged with respect to the transcription factor FOXM1, which demonstrated a significant regulatory role in genes positively correlated with the proportions of M0 and M1 macrophages, while displaying a negative correlation with the proportion of M2 macrophages in breast cancer tissue.

Conclusion

Our research provides new insight into the biomarkers and immune infiltration of TNBC, which could be useful for clinical diagnosis of TNBC.

Suppression of TRIM72-mediated endoplasmic reticulum stress facilitates FOXM1 promotion of diabetic ulcer healing

Foot ulcers are amongst the most prevalent complications of diabetes, known for their delayed healing process. Recent research indicates that the transcription factor forkhead box M1 (FOXM1) plays a role in promoting diabetic ulcer repair. However, the precise mechanisms underlying FOXM1 functions in this context remain unclear. This study aimed to clarify the role of tripartite motif-containing protein 72 (TRIM72)-mediated endoplasmic reticulum stress in FOXM1 promotive effects. Immunohistochemistry revealed that FOXM1 expression was significantly reduced in the lesion tissues of diabetic foot ulcer patients. In vitro experiments revealed a decrease in FOXM1 expression in cultured dermal fibroblasts under high glucose conditions. Activating FOXM1 with a plasmid accelerated the proliferation, migration, and differentiation of dermal fibroblasts and mitigated endoplasmic reticulum stress under high glucose conditions. Additionally, ChIP and luciferase reporter gene assays confirmed that FOXM1 suppressed TRIM72 expression transcriptionally by binding to its promoter. Furthermore, high glucose induced ubiquitination of adenosine 5'-monophosphate-activated protein kinase alpha (AMPKα), whilst inactivation of AMPKα signalling reversed the aforementioned effects of FOXM1 on cells. Finally, the FOXM1-overexpressing plasmid was transfected in vivo, which promoted wound healing in a murine diabetic ulcer model. In conclusion, FOXM1 reduces endoplasmic reticulum stress by inhibiting TRIM72-mediated AMPKα ubiquitination, thereby accelerating the healing of diabetic ulcers.

The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines

Preclinical studies for wound healing disorders are an essential step in translating discoveries into therapies. Also, they are an integral component of initial safety screening and gaining mechanistic insights using an in vivo approach. Given the complexity of the wound healing process, existing guidelines for animal testing do not capture key information due to the inevitable variability in experimental design. Variations in study interpretation are increased by complexities associated with wound aetiology, wounding procedure, multiple treatment conditions, wound assessment, and analysis, as well as lack of acknowledgement of limitation of the model used. Yet, no standards exist to guide reporting crucial experimental information required to interpret results in translational studies of wound healing. Consistency in reporting allows transparency, comparative, and meta-analysis studies and avoids repetition and redundancy. Therefore, there is a critical and unmet need to standardise reporting for preclinical wound studies. To aid in reporting experimental conditions, The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines have now been created by the authors working with the Wound Care Collaborative Community (WCCC) GAPS group to provide a checklist and reporting template for the most frequently used preclinical models in support of development for human clinical trials for wound healing disorders. It is anticipated that the WRAHPS Guidelines will standardise comprehensive methods for reporting in scientific manuscripts and the wound healing field overall. This article is not intended to address regulatory requirements but is intended to provide general guidelines on important scientific considerations for such studies.

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.

Reprogramming of epidermal keratinocytes by PITX1 transforms the cutaneous cellular landscape and promotes wound healing

Cutaneous wound healing is a slow process that often terminates with permanent scarring while oral wounds, in contrast, regenerate after damage faster. Unique molecular networks in epidermal and oral epithelial keratinocytes contribute to the tissue-specific response to wounding, but key factors that establish those networks and how the keratinocytes interact with their cellular environment remain to be elucidated. The transcription factor PITX1 is highly expressed in the oral epithelium but is undetectable in cutaneous keratinocytes. To delineate if PITX1 contributes to oral keratinocyte identity, cell-cell interactions, and the improved wound healing capabilities, we ectopically expressed PITX1 in the epidermis of murine skin. Using comparative analysis of murine skin and oral (buccal) mucosa with single-cell RNA-Seq and spatial transcriptomics, we found that PITX1 expression enhances epidermal keratinocyte migration and proliferation and alters differentiation to a quasi-oral keratinocyte state. PITX1+ keratinocytes reprogrammed intercellular communication between skin-resident cells to mirror buccal tissue while stimulating the influx of neutrophils that establish a pro-inflammatory environment. Furthermore, PITX1+ skin healed significantly faster than control skin via increased keratinocyte activation and migration and a tunable inflammatory environment. These results illustrate that PITX1 programs oral keratinocyte identity and cellular interactions while revealing critical downstream networks that promote wound closure.

Hyperglycemia-Enhanced Neutrophil Extracellular Traps Drive Mucosal Immunopathology at the Oral Barrier

Type 2 diabetes (T2D) is a risk factor for mucosal homeostasis and enhances the susceptibility to inflammation, in which neutrophils have been increasingly appreciated for their role. Here, barrier disruption and inflammation are observed at oral mucosa (gingiva) of T2D patients and mice. It is demonstrated that neutrophils infiltrate the gingival mucosa of T2D mice and expel obvious neutrophil extracellular traps (NETs), while removal of NETs alleviates the disruption of mucosal barrier. Mechanistically, gingival neutrophils released NETs are dependent of their metabolic reprogramming. Under hyperglycemic condition, neutrophils elevate both glucose incorporation and glycolysis via increased expression of GLUT1. Moreover, significantly increased levels of NETs are observed in local gingival lesions of patients, which are associated with clinical disease severity. This work elucidates a causative link between hyperglycemia and oral mucosal immunopathology, mediated by the altered immuno-metabolic axis in neutrophil, thereby suggesting a potential therapeutic strategy.

CLEC14A facilitates angiogenesis and alleviates inflammation in diabetic wound healing

BACKGROUND

Delayed wound healing is a serious complication of diabetic wounds, posing a significant challenge to the treatment of patients with diabetes. Diabetic wound healing is a complex dynamic process involving angiogenesis and inflammatory responses. Currently, there are limited targeted therapies to promote diabetic wound healing. This study aimed to reveal the role of CLEC14A in the process of diabetic wound healing, with the hope of identifying new therapeutic targets to accelerate the healing of diabetic wounds.

METHODS

In vivo, diabetic mice were generated by combined streptozotocin (STZ) and high-fat diet treatment. The wound healing model was established in wild-type and Clec14a-/- diabetic mice. The degree of wound healing, as well as angiogenesis and inflammation during the healing process, were evaluated through Hematoxylin and Eosin (H&E) staining, immunohistochemical staining, and immunofluorescence staining. In vitro, the angiogenic activities of Human Umbilical Vein Endothelial Cells (HUVECs) were assessed following treatment with high glucose and adenoviruses overexpressing CLEC14A, using scratch assays and tube formation assays. Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) were utilized to evaluate the levels of inflammation in HUVECs.

RESULTS

CLEC14A expression was suppressed in diabetic wounds. Deletion of the Clec14a inhibited angiogenesis and activated inflammatory responses in vivo. High-glucose treatment led to decreased CLEC14A expression, impaired angiogenic capacity, and elevated inflammatory levels in vitro. However, adenoviral-mediated overexpression of CLEC14A reversed the response induced by high glucose.

CONCLUSION

CLEC14A accelerates diabetic wound healing by promoting angiogenesis and reducing wound inflammation.

Novel Supramolecular Hydrogel for Infected Diabetic Foot Ulcer Treatment

Multifunctional responsive hydrogels hold significant promise for diabetic foot ulcer (DFU) treatment, though their complex design and manufacturing present challenges. This study introduces a novel supramolecular guanosine-phenylboronic-chlorogenic acid (GBC) hydrogel developed using a dynamic covalent strategy. The hydrogel forms through guanosine quadruplex assembly in the presence of potassium ions and chlorogenic acid (CA) linkage via dynamic borate bonds. GBC hydrogels exhibit pH and glucose responsiveness, releasing more chlorogenic acid under acidic and high glucose conditions due to borate bond dissociation and G-quadruplex (G4) hydrogel disintegration. Experimental results indicate that GBC hydrogels exhibit good self-healing, shear-thinning, injectability, and swelling properties. Both in vitro and in vivo studies demonstrate the GBC hydrogel's good biocompatibility, ability to eliminate bacteria and reactive oxygen species (ROS), facilitate macrophage polarization from the M1 phenotype to the M2 phenotype (decreasing CD86 expression and increasing CD206 expression), exhibit anti-inflammatory effects (reducing TNF-α expression and increasing IL-10 expression), and promote angiogenesis (increasing VEGF, CD31, and α-SMA expression). Thus, GBC hydrogels accelerate DFU healing and enhance tissue remodeling and collagen deposition. This work provides a new approach to developing responsive hydrogels to expedite DFU healing.

SDC4 protein action and related key genes in nonhealing diabetic foot ulcers based on bioinformatics analysis and machine learning

Diabetic foot ulcers (DFU) is a complication associated with diabetes characterised by high morbidity, disability, and mortality, involving chronic inflammation and infiltration of multiple immune cells. We aimed to identify the critical genes in nonhealing DFU using single-cell RNA sequencing, transcriptomic analysis and machine learning. The GSE165816, GSE134431, and GSE143735 datasets were downloaded from the GEO database. We processed and screened the datasets, and identified the cell subsets. Each cell subtype was annotated, and the predominant cell types contributing to the disease were analysed. Key genes were identified using the LASSO regression algorithm, followed by verification of model accuracy and stability. We investigated the molecular mechanisms and changes in signalling pathways associated with this disease using immunoinfiltration analysis, GSEA, and GSVA. Through scRNA-seq analysis, we identified 12 distinct cell clusters and determined that the basalKera cell type was important in disease development. A high accuracy and stability prediction model was constructed incorporating five key genes (TXN, PHLDA2, RPLP1, MT1G, and SDC4). Among these five genes, SDC4 has the strongest correlation and plays an important role in the development of DFU. Our study identified SDC4 significantly associated with nonhealing DFU development, potentially serving as new prevention and treatment strategies for DFU.

The role of Q10 engineering mesenchymal stem cell-derived exosomes in inhibiting ferroptosis for diabetic wound healing

Background

Ferroptosis plays an essential role in the development of diabetes and its complications, suggesting its potential as a therapeutic target. Stem cell-derived extracellular vesicles (EVs) are increasingly being developed as nano-scale drug carriers. The aim of this study was to determine the role of ferroptosis in the pathogenesis of diabetic wound healing and evaluate the therapeutic effects of coenzyme Q10 (Q10)-stimulated exosmes derived from mesenchymal stem cells (MSCs).

Methods

Human keratinocytes (HaCaTs) were exposed to high glucose (HG) conditions in vitro to mimic diabetic conditions, and the ferroptosis markers and expression level of acyl-coenzyme A synthase long-chain family member 4 (ACSL4) were determined. Exosomes were isolated from control and Q10-primed umbilical cord mesenchymal stem cells (huMSCs) and characterized by tramsmission electron microscopy and immunofluorescence staining. The HG-treated HaCaTs were cultured in the presence of exosomes derived from Q10-treated huMSCs (Q10-Exo) and their in vitro migratory capacity was analyzed.

Results

Q10-Exo significantly improved keratinocyte viability and inhibited ferroptosis in vitro. miR-548ai and miR-660 were upregulated in the Q10-Exo and taken up by HaCaT cells. Furthermore, miR-548ai and miR-660 mimics downregulated ACSL4-inhibited ferroptosis in the HG-treated HaCaT cells and enhanced their proliferation and migration. However, simultaneous upregulation of ACSL4 reversed their effects. Q10-Exo also accelerated diabetic wound healing in a mouse model by inhibiting ACSL4-induced ferroptosis.

Conclusions

Q10-Exo promoted the proliferation and migration of keratinocytes and inhibited ferroptosis under hyperglycemic conditions by delivering miR-548ai and miR-660. Q10-Exo also enhanced cutaneous wound healing in diabetic mice by repressing ACSL4-mediated ferroptosis.

Fibroblast-Mediated Macrophage Recruitment Supports Acute Wound Healing

Epithelial and immune cells have long been appreciated for their contribution to the early immune response after injury; however, much less is known about the role of mesenchymal cells. Using single-nuclei RNA sequencing, we defined changes in gene expression associated with inflammation 1 day after wounding in mouse skin. Compared with those in keratinocytes and myeloid cells, we detected enriched expression of proinflammatory genes in fibroblasts associated with deeper layers of the skin. In particular, SCA1+ fibroblasts were enriched for numerous chemokines, including CCL2, CCL7, and IL-33, compared with SCA1- fibroblasts. Genetic deletion of Ccl2 in fibroblasts resulted in fewer wound-bed macrophages and monocytes during injury-induced inflammation, with reduced revascularization and re-epithelialization during the proliferation phase of healing. These findings highlight the important contribution of fibroblast-derived factors to injury-induced inflammation and the impact of immune cell dysregulation on subsequent tissue repair.

The Potential of Mesenchymal Stem/Stromal Cells in Diabetic Wounds and Future Directions for Research and Therapy-Is It Time for Use in Everyday Practice?

The treatment of diabetic wounds is impaired by the intricate nature of diabetes and its associated complications, necessitating novel strategies. The utilization of mesenchymal stem/stromal cells (MSCs) as a therapeutic modality for chronic and recalcitrant wounds in diabetic patients is an active area of investigation aimed at enhancing its therapeutic potential covering tissue regeneration. The threat posed to the patient and their environment by the presence of a diabetic foot ulcer (DFU) is so significant that any additional therapeutic approach that opens new pathways to halt the progression of local changes, which subsequently lead to a generalized inflammatory process, offers a chance to reduce the risk of amputation or even death. This article explores the potential of MSCs in diabetic foot ulcer treatment, examining their mechanisms of action, clinical application challenges, and future directions for research and therapy.

eIF6 modulates skin wound healing by upregulating keratin 6B

Eukaryotic translation initiation factor 6 (eIF6) plays a crucial role in 60S ribosome biogenesis and protein translation, as well as in hypertrophic scar formation, but its potential role in epithelialization is still poorly understood. Herein, we found that eIF6 negatively correlated with the wound healing process. Mice with genetically knockdown eIF6 (eIF6+/-) showed faster re-epithelization as shown by the longer tongue of the newly formed epidermis. Furthermore, eIF6 ablation accelerated the wound healing process by targeting basal keratinocytes in the eIF6 keratinocyte-conditional knockout (eIF6f/+; Krt5-Cre+) mice. Mechanistically, keratin 6B, an important wound-activated protein, was significantly upregulated in eIF6f/+; Krt5-Cre+ mice skin as proved by RNA-seq, western immunoblots, and immunofluorescence staining. Moreover, an elevated level of KRT6B and accelerated proliferative capacity were also observed in stable knockdown eIF6 HaCaT cells. Taken together, eIF6 downregulation could accelerate epithelialization by upregulating KRT6B expression and promoting keratinocyte proliferation. Our results for the first time indicate that eIF6 might be a novel target to regulate re-epithelialization.

ECRG4 mediates host response to cutaneous infection by regulating neutrophil recruitment and adhesion receptor expression

Rapid neutrophil recruitment is critical for controlling infection, with dysfunctional neutrophil responses in diseases like diabetes associated with greater morbidity and mortality. We have shown that the leukocyte protein ECRG4 enhances early neutrophil recruitment to cutaneous wounds and hypothesized that ECRG4 regulates the early host response to infection. Using a cutaneous infection model, we found that ECRG4 KO mice had decreased early neutrophil recruitment with persistent larger lesions, increased bacterial proliferation and systemic dissemination. Although previous work identified ECRG4 as a negative regulator of CD44 on neutrophils, the mechanism regulating neutrophil recruitment remained unknown. We demonstrated that pro-inflammatory responses were intact in ECRG4 KO mice, but found decreased neutrophil mobilization from bone marrow and decreased migration to chemokines. ECRG4 KO mouse neutrophils demonstrated an increase in adhesion molecules that regulate recruitment, including enhanced induction of integrin CD11b and increased L-selectin and CD44 on bone marrow neutrophils. Analysis of gene expression in leukocytes from diabetic patients found decreased ECRG4 expression with similar increased L-selectin and CD44. We propose a previously unrecognized mechanism governing neutrophil recruitment, whereby ECRG4 mediates neutrophil surface adhesion molecules that determine both recruitment and outside-in signaling that modulates neutrophil response to pro-inflammatory stimuli.

Multi-drug resistant Staphylococcus epidermidis from chronic wounds impair healing in human wound model

Venous leg ulcers (VLUs) represent one of the most prevalent types of chronic wounds characterised by perturbed microbiome and biofilm-forming bacteria. As one of the most abundant skin-commensal, Staphylococcus epidermidis is known as beneficial for the host, however, some strains can form biofilms and hinder wound healing. In this study, S. epidermidis distribution in VLUs and associated resistome were analysed in ulcer tissue from patients. Virulence of S. epidermidis isolates from VLUs were evaluated by whole genome sequencing, antimicrobial susceptibility testing, in vitro biofilm and binding assays, and assessment of biofilm-forming capability and pro-inflammatory potential using human ex vivo wound model. We demonstrated that S. epidermidis isolates from VLUs inhibit re-epithelialization through biofilm-dependent induction of IL-1β, IL-8, and IL-6 which was in accordance with impaired healing outcomes observed in patients. High extracellular matrix binding ability of VLU isolates was associated with antimicrobial resistance and expression levels of the embp and sdrG, responsible for bacterial binding to fibrinogen and fibrin, respectively. Finally, we showed that S. epidermidis from VLUs demonstrate pathogenic features with ability to impair healing which underscores the emergence of treatment-resistant virulent lineages in patients with chronic ulcers.

Bionic sulfated glycosaminoglycan-based hydrogel inspired by snail mucus promotes diabetic chronic wound healing via regulating macrophage polarization

The treatment of diabetic foot ulcers remains a significant challenge, as their morbidity is increasing while current therapies are expensive and often ineffective. The dried mucus from the snail Achatina fulica promotes diabetic wound healing. Herein, to develop a more controllable and stable wound dressing for diabetic wound treatment, the AFG/StarPEG hydrogel mimicking snail mucus was prepared by covalently coupling of sulfated glycosaminoglycan from A. fulica (AFG) with star-shaped polyethylene glycol (StarPEG) amine. The AFG/StarPEG hydrogel reduced excessive inflammation in wound tissues by decreasing pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and increasing anti-inflammatory cytokines (IL-4 and IL-10). Moreover, it promoted the polarization of macrophages to M2 anti-inflammatory type in diabetic wound. By improving transition of diabetic chronic wound from inflammatory phase to proliferative phase, it promoted angiogenesis, collagen deposition and re-epithelialization, and thus tissue regeneration for wound healing. This work provides a convenient and effective dressing for treating chronic diabetic wound.