FOXM1 network in association with TREM1 suppression regulates NET formation in diabetic foot ulcers
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ABSTRACT: Diabetic foot ulcers (DFU) are a serious complication of diabetes mellitus and associated with reduced quality of life and high mortality rate. DFUs are characterized by a deregulated immune response with decreased neutrophils due to loss of the transcription factor, FOXM1. Diabetes primes neutrophils to form neutrophil extracellular traps (NETs), contributing to tissue damage and impaired healing. However, the role of FOXM1 in priming diabetic neutrophils to undergo NET formation remains unknown. Here, we found that FOXM1 regulates reactive oxygen species (ROS) levels in neutrophils. Inhibition of FOXM1 results in increased ROS leading to NET formation. Next generation sequencing revealed TREM1 promoted the recruitment of FOXM1+ neutrophils and reversed effects of diabetes and promoted wound healing in vivo. Moreover, we found TREM1 expression correlated with clinical healing outcomes of DFUs, indicating TREM1 may serve as a useful biomarker or a potential therapeutic target. Our findings highlight the clinical relevance of TREM1, and indicates FOXM1 pathway as a novel regulator of NET formation during diabetic wound healing, revealing new therapeutic strategies to promote healing in DFUs.
Project description:Diabetic foot ulcers (DFU) are a serious complication of diabetes mellitus and associated with reduced quality of life and high mortality rate. DFUs are characterized by a deregulated immune response with decreased neutrophils due to loss of the transcription factor, FOXM1. Diabetes primes neutrophils to form neutrophil extracellular traps (NETs), contributing to tissue damage and impaired healing. However, the role of FOXM1 in priming diabetic neutrophils to undergo NET formation remains unknown. Here, we found that FOXM1 regulates reactive oxygen species (ROS) levels in neutrophils and inhibition of FOXM1 results in increased ROS leading to NET formation. Next generation sequencing revealed that TREM1 promoted the recruitment of FOXM1+ neutrophils and reversed effects of diabetes and promoted wound healing in vivo. Moreover, we found that TREM1 expression correlated with clinical healing outcomes of DFUs, indicating TREM1 may serve as a useful biomarker or a potential therapeutic target. Our findings highlight the clinical relevance of TREM1, and indicates FOXM1 pathway as a novel regulator of NET formation during diabetic wound healing, revealing new therapeutic strategies to promote healing in DFUs.
Project description:Despite the hyperproliferative environment marked by activation of β-catenin and overexpression of c-myc, the epidermis surrounding chronic diabetic foot ulcers (DFUs) is clinically hypertrophic and nonmigratory yet does not undergo malignant transformation. We identified miR193b-3p as a master regulator that contributes to this unique cellular phenotype. We determined that induction of tumor suppressor miR193b-3p is a unique feature of DFUs that is not found in venous leg ulcers, acute wounds, or cutaneous squamous cell carcinoma (SCC). Genomic analyses of DFUs identified suppression of the miR193b-3p target gene network that orchestrates cell motility. Inhibition of migration and wound closure was further confirmed by overexpression of miR193b-3p in human organotypic and murine in vivo wound models, whereas miR193b-3p knockdown accelerated wound reepithelialization in human ex vivo and diabetic murine wounds in vivo. The dominant negative effect of miR193b-3p on keratinocyte migration was maintained in the presence of promigratory miR31-5p and miR15b-5p, which were also overexpressed in DFUs. miR193b-3p mediated antimigratory activity by disrupting stress fiber formation and by decreasing activity of GTPase RhoA. Conversely, miR193b-3p targets that typically participate in malignant transformation were found to be differentially regulated between DFUs and SCC, including the proto-oncogenes KRAS (Kirsten rat sarcoma viral proto-oncogene) and KIT (KIT proto-oncogene). Although miR193b-3p acts as a tumor suppressor contributing to low tumor incidence in DFUs, it also acts as a master inhibitor of cellular migration and epithelialization in DFUs. Thus, miR193b-3p may represent a target for wound healing induction, cancer therapeutics, and diagnostics.
Project description:In this pilot study, we optimized diabetic foot ulcers (DFUs) single-cell profiling from debrided DFUs of underrepresented African American (AA) patients. The healing-DFUs were significantly enriched (P=0.03) with unique heterogenous Healing-associated Fibroblasts (HE-Fibro), expressing inflammation (CHI3L1), ECM-remodeling (MMP13, ASPN) and wound healing (NRG1, COL7A1) associated genes, validating our previous findings with surgically resected healer-DFUs. HE-Fibro/Fibro cells depicted significantly lower expression of key healing-associated CHIL3L1, and TIMP1 genes in AAs compared to Whites, signifying race-associated heterogeneity. Reparative M2 macrophages were enriched in Healing-DFUs (P=0.05), while inflammatory M1 macrophages displayed distinct transcriptome differences in Nonhealing-DFUs and Healing-DFUs. Cellular communication analysis revealed a pivotal role for HE-Fibro/Fibroblasts (signal-senders) and M1 (signal-receivers). HE-Fibro’s signaling significantly upregulated wound-resolving WNT, and ECM-remodeling CXCL pathways in Healing-DFUs, while M1 signaling upregulated healing-disruptive, and inflammation-associated, SPP1 pathways, in Nonhealing-DFUs. This study justifies using debrided tissues for single-cell assays and highlights the need for in-depth investigations into dysregulated wound healing microenvironments in AAs.
Project description:Monocyte chemotactant protein-1 (MCP-1), a pro-inflammatory cytokine, plays an important role in inflammatory process. In present study, we evaluated the association of MCP-1 gene rs1024611 polymorphism with risk and clinical characteristics of diabetic foot ulcers (DFUs).This study recruited 116 patients with DFUs, 135 patients with diabetes mellitus (DM) without complications (non-DFU), and 149 healthy controls (HCs). MCP-1 gene rs1024611 polymorphism was genotyped by direct sequencing. The expression of MCP-1 was analyzed using quantitative real-time polymerase chain reaction. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assume the association strength.Individuals with rs1024611 AG and GG genotypes exhibited significantly higher susceptibility to DFUs, in the comparison with HCs (AG vs AA, OR = 2.364, 95% CI = 1.021-5.470; GG vs AA, OR = 2.686, 95% CI = 1.154-6.255). Meanwhile, G allele was associated with increased DFUs susceptibility (OR = 1.457, 95% CI = 1.014-2.093). Besides, rs1024611 SNP was slightly correlated with increased DFUs susceptibility in patients with DM. GG genotype of rs1024611 was significantly correlated with higher epidermal thickness and lower dermis thickness in patients with DFUs (P < .01). Patients with DFU exhibited upregulation of MCP-1 mRNA, and GG genotype was correlated with enhanced MCP-1 expression in DFU and non-DFU groups.Rs1024611 polymorphism was significantly associated with MCP-1 expression and individual susceptibility to DFUs.
Project description:Diabetic foot ulcers (DFUs) are a devastating complication of diabetes. In order to identify systemic and local factors associated with DFU healing, we examined the cellular landscape of DFUs by single-cell RNA-seq analysis of foot and forearm skin specimens, as well as PBMC samples, from 10 non-diabetic subjects, and 17 diabetic patients, 11 with, and 6 without DFU. Our analysis shows enrichment of a unique inflammatory fibroblast population in DFU patients with healing wounds. The patients with healing DFUs also depicted enrichment of macrophages with M1 polarization, as opposed to more M2 macrophages in non-healing wounds. These findings were verified using Immunohistochemistry and Spatial Transcriptomics.
Project description:OBJECTIVE:This study evaluated the association between hemoglobin A1c (A1C) and wound outcomes in patients with diabetic foot ulcers (DFUs). RESEARCH DESIGN AND METHODS:We conducted a retrospective analysis of an ongoing prospective, clinic-based study of patients with DFUs treated at an academic institution during a 4.7-year period. Data from 270 participants and 584 wounds were included in the analysis. Cox proportional hazards regression was used to assess the incidence of wound healing at any follow-up time in relation to categories of baseline A1C and the incidence of long-term (≥90 days) wound healing in relation to tertiles of nadir A1C change and mean A1C change from baseline, adjusted for potential confounders. RESULTS:Baseline A1C was not associated with wound healing in univariate or fully adjusted models. Compared with a nadir A1C change from baseline of -0.29 to 0.0 (tertile 2), a nadir A1C change of 0.09 to 2.4 (tertile 3) was positively associated with long-term wound healing in the subset of participants with baseline A1C <7.5% (hazard ratio [HR] 2.07; 95% CI 1.08-4.00), but no association with wound healing was seen with the mean A1C change from baseline in this group. Neither nadir A1C change nor mean A1C change were associated with long-term wound healing in participants with baseline A1C ≥7.5%. CONCLUSIONS:There does not appear to be a clinically meaningful association between baseline or prospective A1C and wound healing in patients with DFUs. The paradoxical finding of accelerated wound healing and increase in A1C in participants with better baseline glycemic control requires confirmation in further studies.
Project description:IntroductionDiabetic foot ulcers (DFUs) are the most common foot injuries leading to lower extremity amputation in diabetic patients. Recent studies showed that long non-coding RNAs (lncRNAs) played important roles in diverse biological processes. In this study, we focused on identifying differentially expressed long non-coding RNAs (lncRNAs) in DFU.Material and methodsReal-time PCR assay was performed to validate the expression pattern of lncRNAs in DFU. Moreover, co-expression networks were also constructed to identify hub lncRNAs in DFU. Specifically, gene ontology (GO) analysis was first performed to evaluate the potential roles of differentially expressed genes (DEGs) and lncRNAs in DFU.ResultsIn the present study, we identified 58 up-regulated lncRNAs and 42 down-regulated lncRNAs in DFU samples compared to non-diabetic foot skin samples by analyzing the GSE68186 dataset. Four lncRNAs (FLJ30679, LINC01193, LINC00692, and LINC00641) were observed to be up-regulated in DFU. Furthermore, we found that the down-regulated lncRNA-mediated co-expression network contained 42 lncRNAs and 700 DEGs and the up-regulated lncRNA mediated co-expression network contained 58 lncRNAs and 688 DEGs.ConclusionsBioinformatics analysis showed that differentially expressed lncRNAs were involved in regulating the ERK1 and ERK2 cascade, secondary alcohol biosynthetic process, centrosome duplication and DNA repair. These results suggested the potential prognostic value of lncRNAs in DFU.
Project description:Diabetic foot ulcers (DFUs) are a serious complication of diabetes that results in significant morbidity and mortality. Mortality rates associated with the development of a DFU are estimated to be 5% in the first 12 months, and 5-year morality rates have been estimated at 42%. The standard practices in DFU management include surgical debridement, dressings to facilitate a moist wound environment and exudate control, wound off-loading, vascular assessment, and infection and glycemic control. These practices are best coordinated by a multidisciplinary diabetic foot wound clinic. Even with this comprehensive approach, there is still room for improvement in DFU outcomes. Several adjuvant therapies have been studied to reduce DFU healing times and amputation rates. We reviewed the rationale and guidelines for current standard of care practices and reviewed the evidence for the efficacy of adjuvant agents. The adjuvant therapies reviewed include the following categories: nonsurgical debridement agents, dressings and topical agents, oxygen therapies, negative pressure wound therapy, acellular bioproducts, human growth factors, energy-based therapies, and systemic therapies. Many of these agents have been found to be beneficial in improving wound healing rates, although a large proportion of the data are small, randomized controlled trials with high risks of bias.