Project description:We performed RNA-seq on tissue biopsies derived from patients with DFUs and compared it to human oral and skin wounds to identify the molecular mechanisms and transcriptional networks that are deregulated in DFUs. Our results identified a unique inflammatory transcriptional signature unique to oral and skin wounds involved in promoting cell proliferation and cell survival of immune cells that are deficient in DFUs. In addition, we identified a signature immune-cell profile in which activation and proliferation of macrophages and neutrophils were absent in DFUs. These results suggest that a deregulated immune response in which impaired activation, proliferation and survival of immune cells contribute to pathogenesis of DFUs and provides novel avenues for development of therapies aimed at reprogramming DFUs into healing-competent wounds.
Project description:Diabetic foot ulcers (DFUs) are a life-threatening disease that often result in lower limb amputations and a shortened lifespan. However, molecular mechanisms contributing to the pathogenesis of DFUs remain poorly understood. We use next-generation sequencing to generate a human dataset of pathogenic DFUs to compare to transcriptional profiles of human skin and oral acute wounds, oral as a model of "ideal" adult tissue repair due to accelerated closure without scarring. Here we identify major transcriptional networks deregulated in DFUs that result in decreased neutrophils and macrophages recruitment and overall poorly controlled inflammatory response. Transcription factors FOXM1 and STAT3, which function to activate and promote survival of immune cells, are inhibited in DFUs. Moreover, inhibition of FOXM1 in diabetic mouse models (STZ-induced and db/db) results in delayed wound healing and decreased neutrophil and macrophage recruitment in diabetic wounds in vivo. Our data underscore the role of a perturbed, ineffective inflammatory response as a major contributor to the pathogenesis of DFUs, which is facilitated by FOXM1-mediated deregulation of recruitment of neutrophils and macrophages, revealing a potential therapeutic strategy.
Project description:MicroRNAs are powerful gene expression regulators, but their corneal repertoire and potential changes in corneal diseases remain unknown. Our purpose was to identify miRNAs altered in the human diabetic cornea by microarray analysis, and to examine their effects on wound healing in cultured telomerase-immortalized human corneal epithelial cells (HCEC) in vitro. Using microarrays, 29 miRNAs were identified as differentially expressed in diabetic samples. Two miRNA candidates showing the highest fold increased in expression in the diabetic cornea were confirmed by Q-PCR and further characterized. HCEC transfection with h-miR-146a or h-miR-424 significantly retarded wound closure, but their respective antagomirs significantly enhanced wound healing vs. controls. Cells treated with h-miR-146a or h-miR-424 had decreased p-p38 and p-EGFR staining, but these increased over control levels close to the wound edge upon antagomir treatment. In conclusion, several miRNAs with increased expression in human diabetic central corneas were found. Two such miRNAs inhibited cultured corneal epithelial cell wound healing. Dysregulation of miRNA expression in human diabetic cornea may be an important mediator of abnormal wound healing. Total RNA was extracted from age-matched human autopsy normal (n=6) and diabetic (n=6) central corneas, Flash Tag end-labeled, and hybridized to Affymetrix® GeneChip® miRNA Arrays. Select miRNAs associated with diabetic cornea were validated by quantitative RT-PCR (Q-PCR) and by in situ hybridization (ISH) in independent samples.
Project description:Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus, which causes great health damage and economic burden to patients. The pathogenesis of DFU is not fully understood.We screened wound healing-related genes using bioinformatics analysis, and full-thickness skin injury mice model and cellular assays were used to explore the role of target genes in diabetic wound healing. SFRP2 was identified as a wound healing-related gene, and the expression of SFRP2 is associated with immune cell infiltration in DFU. In vivo study showed that suppression of SFRP2 delayed the wound healing process of diabetic mice, impeded angiogenesis and matrix remodeling, and increased macrophage infiltration in wound tissues. In addition, suppression of SFRP2 enhanced M1 polarization in both the early and later stage of wound healing, and decreased M2 polarization in the later stage, which impeded the transition of M1 to M2 polarization of wound healing. Moreover, suppression of SFRP2 affected the transcriptome signatures-related to inflammatory response and energy metabolism at the early stage of wound healing. Extracellular flux analysis (EFA) showed that suppression of SFRP2 decreased mitochondrial energy metabolism and increased glycolysis in injury-related macrophages. Furthermore, suppression of SFRP2 inhibited transcriptome signaturesrelated to carbohydrate metabolism, lipid metabolism and amino acid metabolism, which consists the three main components of energy metabolism of macrophages. In conclusions, SFRP2 may function as a wound healing-related gene in DFU, and suppression of SFRP2 impaired diabetic wound healing by compromising the M1-to-M2 transition of macrophages and modulating the balance between mitochondrial energy metabolism and glycolysis.
Project description:Wound healing is impaired by infection; however, how microbe-induced inflammation modulates tissue repair remains unclear. We took advantage of the optical transparency of zebrafish and a genetically tractable microbe, Listeria monocytogenes, to probe the role of infection and inflammation in wound healing. We found a critical window of microbial clearance necessary to limit persistent inflammation and enable efficient wound repair. Infection with bacteria engineered to activate the inflammasome, Lm-Pyro, induced persistent inflammation and impaired healing despite low bacterial burden. In contrast, infection with an anti-inflammatory, apoptosis inducing strain, Lm-Apo, had similar infectious burden but was associated with rapid wound repair. Inflammatory infections induced il-1b expression and blocking IL-1R signaling partially rescued wound healing in the presence of persistent infection. Taken together, our findings suggest that the dynamics of microbe-induced tissue inflammation impacts repair in complex tissue damage independent of bacterial load, with a critical early window for efficient tissue repair.
Project description:Impaired skin wound healing is a significant global health issue, especially among the elderly. Wound healing is a well-orchestrated process involving the sequential phases of inflammation, proliferation, and tissue remodeling. Although wound healing is a highly dynamic and energy-requiring process, the role of metabolism remains largely unexplored. By combining transcriptomics and metabolomics of human skin biopsy samples, we mapped the core bioenergetic and metabolic changes in normal acute as well as chronic wounds in elderly subjects. We found upregulation of glycolysis, the tricarboxylic acid cycle, glutaminolysis, and β-oxidation in the later stages of acute wound healing and in chronic wounds. To ascertain the role of these metabolic pathways on wound healing, we targeted each pathway in a wound healing assay as well as in a human skin explant model using metabolic inhibitors and stimulants. Enhancement or inhibition of glycolysis and, to a lesser extent, glutaminolysis had a far greater impact on wound healing than similar manipulations of oxidative phosphorylation and fatty acid β-oxidation. These findings increase the understanding of wound metabolism and identify glycolysis and glutaminolysis as potential targets for therapeutic intervention.
Project description:MicroRNAs are powerful gene expression regulators, but their corneal repertoire and potential changes in corneal diseases remain unknown. Our purpose was to identify miRNAs altered in the human diabetic cornea by microarray analysis, and to examine their effects on wound healing in cultured telomerase-immortalized human corneal epithelial cells (HCEC) in vitro. Using microarrays, 29 miRNAs were identified as differentially expressed in diabetic samples. Two miRNA candidates showing the highest fold increased in expression in the diabetic cornea were confirmed by Q-PCR and further characterized. HCEC transfection with h-miR-146a or h-miR-424 significantly retarded wound closure, but their respective antagomirs significantly enhanced wound healing vs. controls. Cells treated with h-miR-146a or h-miR-424 had decreased p-p38 and p-EGFR staining, but these increased over control levels close to the wound edge upon antagomir treatment. In conclusion, several miRNAs with increased expression in human diabetic central corneas were found. Two such miRNAs inhibited cultured corneal epithelial cell wound healing. Dysregulation of miRNA expression in human diabetic cornea may be an important mediator of abnormal wound healing.
Project description:Mesenchymal stem cell (MSC)-derived exosomes had been reported to be a prospective candidate in accelerating diabetic wound healing. Hence, this study intended to explore whether exosomes originating from the human umbilical cord MSC (hucMSC) could display a superior proangiogenic effect on diabetic wound repair and its underlying molecular mechanism.
Project description:Diabetic wounds require continuous and coordinated modulation of the microenvironment concurrent with tissue regeneration, yet this remains a significant challenge. As a proof of concept, we herein propose to use dimeric copper peptide for diabetic wound treatment. The dimeric copper peptide (D-CuP) was first synthesized and then incorporated into a reactive oxygen species (ROS)-responsive hydrogel matrix to improve therapeutic compliance, culminating in the formulation of G/D-CuP. Compared to monomer copper peptide (CuP), a wound healing agent, D-CuP exhibits multivalency, enhanced biologic stability against proteases and the broad biological activities, such as anti-inflammatory and antioxidative properties, while promoting angiogenesis and fibroblast proliferation and migration. Meanwhile, the hydrogel matrix, exhibiting excellent ROS-scavenging capabilities, has been engineered to an intelligent drug reservoir for wound-responsive release of D-CuP at the wound site while simultaneously attenuating inflammatory responses. Ultimately, the G/D-CuP group demonstrated superior therapeutic efficacy, achieving in 97.2% closure of infected wounds.In this study, we present a proof-of-concept study to optimize the treatment of diabetic wounds. This method integrates a dimeric copper peptide hydrogel (G/D-CuP) to address several critical factors: i) The design and synthesis of the dimeric copper peptide (D-CuP) feature a broad range of targets and enhanced biological activities, such as anti-inflammatory and antioxidative properties, while promoting angiogenesis and fibroblast proliferation and migration; ii) Utilizing the steric hindrance conferred by dimerization reduces protease access to the active site and significantly improving stability against proteases; iii) A ROS-responsive hydrogel matrix has been synthesized, exhibiting superior ROS-scavenging capabilities, functioning as an intelligent drug reservoir that enables the controlled release of D-CuP at the wound interface while simultaneously attenuating inflammatory responses in the microenvironment; iv) G/D-CuP possesses outstanding deformability and spreadability, allowing it to adapt to any wound shape; v) The synthesis and preparation process of G/D-CuP are straightforward and cost-effective, making it highly promising for clinical translation. This multifunctional treatment platform is anticipated to accommodate the complex and dynamic biological processes involved in diabetic wound healing, thereby significantly improving the overall efficacy of wound healing treatments.