Chronic diabetic wounds are at lifelong risk of developing diabetic foot ulcers owing to severe hypoxia, excessive reactive oxygen species (ROS), a complex inflammatory microenvironment, and the potential for bacterial infection. Here we develop a programmed treatment strategy employing live Haematococcus (HEA). By modulating light intensity, HEA can be programmed to perform a variety of functions, such as antibacterial activity, oxygen supply, ROS scavenging, and immune regulation, suggesting its potential for use in programmed therapy. Under high light intensity (658 nm, 0.5 W/cm²), green HEA (GHEA) with efficient photothermal conversion mediate wound surface disinfection. By decreasing the light intensity (658 nm, 0.1 W/cm²), the photosynthetic system of GHEA can continuously produce oxygen, effectively resolving the problems of hypoxia and promoting vascular regeneration. Continuous light irradiation induces astaxanthin (AST) accumulation in HEA cells, resulting in a gradual transformation from a green to red hue (RHEA). RHEA effectively scavenges excess ROS, enhances the expression of intracellular antioxidant enzymes, and directs polarization to M2 macrophages by secreting AST vesicles via exosomes. The living HEA hydrogel can sterilize and enhance cell proliferation and migration and promote neoangiogenesis, which could improve infected diabetic wound healing in female mice.

Owing to the persistent inflammatory microenvironment and unsubstantial dermal tissues, chronic diabetic wounds do not heal easily and their recurrence rate is high. Therefore, a dermal substitute that can induce rapid tissue regeneration and inhibit scar formation is urgently required to address this concern. In this study, we established biologically active dermal substitutes (BADS) by combining novel animal tissue‐derived collagen dermal‐replacement scaffolds (CDRS) and bone marrow mesenchymal stem cells (BMSCs) for the healing and recurrence treatments of chronic diabetic wounds. The collagen scaffolds derived from bovine skin (CBS) displayed good physicochemical properties and superior biocompatibility. CBS loaded with BMSCs (CBS‐MCSs) could inhibit M1 macrophage polarization in vitro. Decreased MMP‐9 and increased Col3 at the protein level were detected in CBS‐MSCs‐treated M1 macrophages, which may be attributed to the suppression of the TNF‐α/NF‐κB signaling pathway (downregulating phospho‐IKKα/β/total IKKα/β, phospho‐IκB/total IκB, and phospho‐NFκB/total NFκB) in M1 macrophages. Moreover, CBS‐MSCs could benefit the transformation of M1 (downregulating iNOS) to M2 (upregulating CD206) macrophages. Wound‐healing evaluations demonstrated that CBS‐MSCs regulated the polarization of macrophages and the balance of inflammatory factors (pro‐inflammatory: IL‐1β, TNF‐α, and MMP‐9; anti‐inflammatory: IL‐10 and TGF‐β3) in db/db mice. Furthermore, CBS‐MSCs facilitated the noncontractile and re‐epithelialized processes, granulation tissue regeneration, and neovascularization of chronic diabetic wounds. Thus, CBS‐MSCs have a potential value for clinical application in promoting the healing of chronic diabetic wounds and preventing the recurrence of ulcers.

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.

Background: N6-methyladenosine (m⁶A) is the most common and abundant mRNA modification, playing an essential role in biological processes and tumor development. However, the role of m⁶A methylation in skin cutaneous melanoma (SKCM) is not yet clear. This study analyzed the expression of m⁶A-related functional genes in SKCM and aimed to explore the key demethylase ALKBH5 mediated m⁶A modification and its potential mechanism in human SKCM.

Keloid is a benign proliferative disease characterized by excessive deposition of extracellular matrix collagen during skin wound healing. The mechanisms of keloid formation have not been fully elucidated, and the current treatment methods are not effective for all keloid patients. Therefore, there is an urgent need to find more effective therapies, and our research focused on identifying characteristic molecular signatures of keloid to explore potential therapeutic targets. Gene expression profiles of keloid and control group samples were retrieved from the GEO database. Taking the GSE113619 dataset as the training set, the dataset collected skin tissues from non-lesion sites of healthy and keloid-prone individuals, denoted as Day0. The second sampling was performed 42 days later at the original sampling site of control and keloid groups, denoted as Day42.The 'limma' package and Venn diagram identified differentially expressed genes (DEGs) specific to keloid day42 versus day0 samples. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome pathway functional enrichment, and annotation of the characteristic genes were conducted on the Metascape website. Ingenuity canonical pathways, disease & function enrichment analysis and gene interaction network were performed and predicted in Ingenuity Pathway Analysis (IPA) software. Key module genes related to keloid were filtered out by Weighted Gene Co-expression Network Analysis (WGCNA). We utilized the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm to screen the characteristic genes in keloid by the 'glmnet' package. The area under the curve (AUC) of receiver operating characteristic (ROC) was utilized to determine the effectiveness of potential signatures in discriminating keloid samples from normal samples and performed by using the 'pROC' package. The enrich scores of 24 immune cells in each sample were calculated by the single-sample gene set enrichment analysis (ssGSEA) algorithm， and then the Gene Set Variation Analysis (GSVA) was performed. Finally, RNA from 4 normal and 6 keloid samples was extracted, and RT-qPCR and Western Blot validated the expression of characteristic genes. A total of 640 DEGs specific to keloid day42 versus day0 samples were detected. 69 key module genes were uncovered and implicated in 'NCAM signaling for neurite out-growth', 'oncogenic MAPK signaling', 'transmission across chemical synapses' pathways, and the mitotic cell cycle-related processes. Five characteristic genes (MTUS1, UNC5C, CEP57, NAA35, and HOXD3) of keloid were identified by LASSO, and among which UNC5C and HOXD3 were validated by ROC plot in external dataset, RT-qPCR and Western Blot in validation samples. The result of ssGSEA indicated that the infiltration of neutrophils showed a relatively higher abundance and natural killer cells with relatively low enrichment in the keloid group compared to the control group. UNC5C was correlated with more immune cells compared with other characteristic genes. In this study, characteristic genes associated with keloid were identified by bioinformatic approaches and verified in clinical validation samples, providing potential targets for the diagnosis and treatment of keloid.