Project description:In an RNAseq analysis, we have identified the circular RNAs cCHST15 and cTNFRSF21 with high levels in venous ulcers compared to acute wounds or skin. The biological function of these two circular RNAs in human epidermal keratinocytes during wound repair has not been studied. To study the genes regulated by cCHST15 or cTNFRSF21 , we transfected siRNA targeting the diagnostic junctions of either cCHST15 or cTNFRSF21 into human primary epidermal keratinocytes to knockdown cCHST15 or cTNFRSF21 expression, respectively. We performed a global transcriptome analysis of keratinocytes upon circRNA knockdown using Affymetrix arrays.
Project description:Infections of burn wounds, especially those caused by Pseudomonas aeruginosa, could trigger sepsis or septic shock, which is the main cause of death after burn injury. Compared with traditional saline-wet-to-dry dressings, negative pressure wound therapy (NPWT) is more effective for the prevention and treatment of wound infections. However, the mechanism by which NPWT controls infection and accelerates wound healing remains unclear. Accordingly, in this study, the molecular mechanisms underlying the effects of NPWT were explored using a murine model of P. aeruginosa-infected burn wounds. NPWT significantly reduced P. aeruginosa levels in wounds, enhanced blood flow, and promoted wound healing. Additionally, NPWT markedly alleviated wound inflammation and increased the expression of wound healing–related molecules. Recent evidence points to a role of circular RNAs (circRNAs) in wound healing; hence, whole-transcriptome sequencing of wound tissues from NPWT and control groups was performed to evaluate circRNA expression profiles.
Project description:Here we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP-binding cassette subfamily B member 5 (ABCB5) for the therapy of non-healing wounds. Local administration of dermal ABCB5+-derived MSCs attenuated macrophage-dominated inflammation and thereby accelerated healing of full-thickness excisional wounds in the iron overload mouse model mimicking the non-healing state of human venous leg ulcers. The observed beneficial effects were due to interleukin-1 receptor antagonist (IL-1RA) secreted by ABCB5+-derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained pro-inflammatory M1 macrophages towards repair promoting anti-inflammatory M2 macrophages at the wound site. The beneficial anti-inflammatory effect of IL-1RA released from ABCB5+-derived MSCs on human wound macrophages was conserved in humanized NOD-scid IL2rγnull mice. In conclusion, human dermal ABCB5+ cells represent a novel, easy accessible and marker-enriched source of MSCs which holds substantial promise to successfully treat chronic non-healing wounds in humans.
Project description:Severe angiopathy is a major driver for diabetes associated secondary complications. Knowledge on underlying mechanisms essential for advanced therapies to attenuate these pathologies is limited. Injection of ABCB5+ stromal precursors (SPs) at the edge of non-healing diabetic wounds in a murine db/db model, closely mirroring human type II diabetes, profoundly accelerates wound closure. Strikingly, enhanced angiogenesis was substantially enforced by the release of the ribonuclease angiogenin from ABCB5+ SPs. This compensates for the profoundly reduced angiogenin expression in non-treated murine and human chronic diabetic wounds. Silencing of angiogenin in ABCB5+ SPs prior to injection significantly reduced angiogenesis, reduced numbers of M2 macrophages and delayed wound closure in diabetic db/db mice implying an unprecedented key role for angiogenin in tissue regeneration in diabetes. These data hold significant promise for further refining SPs-based therapies of non-healing diabetic foot ulcers and other pathologies with impaired angiogenesis.
Project description:The management of antibiotic-resistant, bacterial biofilm infections in chronic skin wounds is a significant clinical challenge. Despite advances in diagnosis, many patients do not derive benefit from current anti-infective/antibiotic therapies. Here we report a novel class of epoxy-tiglianes and demonstrate their antimicrobial activity (modifying bacterial growth and inducing biofilm disruption), with structure/activity relationships established against important human pathogens. In vitro, the lead candidate, EBC-1013 stimulated PKC-dependent neutrophil ROS induction and NETosis, and increased expression of wound healing associated cytokines, chemokines and antimicrobial peptides in keratinocytes and fibroblasts. In vivo, topical EBC-1013 induced rapid resolution of infection with increased matrix remodelling in acute thermal injuries. In chronically-infected, diabetic wounds, treatment induced cytokine/chemokine production, inflammatory cell recruitment and complete healing (in 6/7 wounds) with ordered keratinocyte differentiation. These results highlight a non-antibiotic approach involving contrasting, orthogonal mechanisms of action: targeted biofilm disruption and innate immune induction in the treatment of chronic wounds.
Project description:The management of antibiotic-resistant, bacterial biofilm infections in chronic skin wounds is a significant clinical challenge. Despite advances in diagnosis, many patients do not derive benefit from current anti-infective/antibiotic therapies. Here we report a novel class of epoxy-tiglianes and demonstrate their antimicrobial activity (modifying bacterial growth and inducing biofilm disruption), with structure/activity relationships established against important human pathogens. In vitro, the lead candidate, EBC-1013 stimulated PKC-dependent neutrophil ROS induction and NETosis, and increased expression of wound healing associated cytokines, chemokines and antimicrobial peptides in keratinocytes and fibroblasts. In vivo, topical EBC-1013 induced rapid resolution of infection with increased matrix remodelling in acute thermal injuries. In chronically-infected, diabetic wounds, treatment induced cytokine/chemokine production, inflammatory cell recruitment and complete healing (in 6/7 wounds) with ordered keratinocyte differentiation. These results highlight a non-antibiotic approach involving contrasting, orthogonal mechanisms of action: targeted biofilm disruption and innate immune induction in the treatment of chronic wounds.
Project description:Impaired healing of diabetic wounds causes significant morbidity and mortality. This study aimed to identify novel mechanisms of diabetic wound healing defects and test a therapeutic intervention using diabetic mouse and pig models. We found Smad7 transgene expression in mouse epidermis promoting wound healing in diabetic db/db mice, with reductions in obesity and blood glucose. To isolate effects of Smad7 on wounds, we created a Smad7-based biologic (Tat-PYC-Smad7) that penetrates wound cells. Topical application of Tat-PYC-Smad7 to diabetic pig and mouse wounds accelerated healing compared to controls. RNAseq analysis of mouse wound samples showed reduced TGFβ/NFκB signaling, leading to faster re-epithelialization and better extracellular matrix remodeling. Tat-PYC-Smad7 also attenuated neutrophil degranulation and NETosis by blocking histone 3 citrullination and inhibiting myeloperoxidase activities. Our study reveals that Tat-PYC-Smad7 promotes diabetic wound healing by targeting keratinocytes and neutrophils, providing insight into cellular mechanisms of diabetic wound healing defects targetable by Smad7-based therapy.
Project description:Circular RNA (circRNA) microarray analysis was performed to examine the expression profiles of circRNAs in diabetic foot ulcers (DFU) and in human excisional skin wounds 7 days after injury.
Project description:Integrative small and long RNA-omics analysis of human healing and non-healing wounds discovers cooperating microRNAs as therapeutic targets
Project description:Integrative small and long RNA-omics analysis of human healing and non-healing wounds discovers cooperating microRNAs as therapeutic targets