Project description:We here addressed the question whether the unique capacity of mesenchymal stromal/stem cells (MSCs) to re-establish tissue homeostasis depends on their potential to sense pathogen associated molecular pattern (PAMP) and, in consequence, mount an adaptive response in the interest of tissue repair. After injection of MSCs which had been primed with the bacterial wall component LPS into murine wounds, an unexpected acceleration of healing occurred, clearly exceeding that of non-primed MSCs. This correlates with a fundamental reprogramming of the transcriptome in LPS treated MSCs as deduced from RNA-seq analysis and its validation. A network of genes mediating the adaptive response through the TLR-4 pathway responsible for neutrophil activation (GCP- 2, ENA-78, IL-1β IL-8) and MSC protection (SOX6) profoundly contributes to enhanced wound healing. In fact, silencing of either TRL-4, or IRAK3, a downstream effector of TRL-4, or SOX6 suppressed wound healing most likely due to suppression of neutrophil extracellular trap formation and suppression of the enhanced microbicidal release of reactive oxygen species (ROS), key features of neutrophil activation. This previously unreported results uncover SOX6 which protects MSCs at the wound site from enhanced oxidative stress. This unprecedented findings hold substantial promise to refine current MSC-based therapies for difficult-to-treat wounds.
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:Adaptive cellular reprogramming is an emerging field to study promotion of a host’s intrinsic healing strategies through changing one somatic cell type into another state or fate; tissue injury is known to enhance such cell conversions. Here we identify a molecular pathway in injured skin, whereby a subset of dermal fibroblasts displays a novel vasculogenic state change with gain in vasculogenic transcripts and endothelial cell-like functions without losing core fibroblast lineage fate phenotypic, functional, and transcriptional characteristics. Removal of microRNA suppression of FLI1 transcription in fibroblasts results in upregulation of a cascade of vasculogenic molecules that heralds the vasculogenic state change in some fibroblasts. FLI1 dependent vasculogenic fibroblast subset emergence in injured skin is blunted in poorly healing skin wounds of diabetic animals but can be restored through topical tissue nanotransfection of a single anti-microRNA oligonucleotide, to rescue tissue perfusion and wound healing. Augmenting a physiologic tissue injury adaptive response mechanism that produces vasculogenic fibroblasts opens new avenues for therapeutic tissue vascularization of ischemic conditions.
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:In order to clarify the human response of re-epithelialization, we biopsied split-thickness skin graft donor site wounds immediately before and after harvesting, as well as during the healing process 3 and 7 days thereafter. Altogether 25 biopsies from 8 patients qualified for the study. All samples were analysed by genome-wide microarrays. Here we identified the genes associated with normal skin re-epithelialization on time-scale, and organized them by similarities according to their induction or suppression patterns during wound healing. Overall 25 samples were analyzed
Project description:It has been reported that mesenchymal stem cells (MSC) derived from adult tissues are effective in promoting wound healing. However, the cell quality varies and cell number is limited as both depend on donations. Moreover, dissociated MSC delivered to an inflammatory lesion are subject to challenges to their survival and functions. Here we demonstrate that dropping of spheres of MSC derived from human embryonic stem cells (EMSC) onto murine dermal wound had much higher survival and efficacy than topical application of dissociated EMSC. RNA sequencing on cells isolated from the wound highlights the CXCL12-CXCR4 signalling in the EMSC sphere-mediated efficacy, which was verified via CXCL12 knockdown in EMSC and CXCR4 inhibition in target cells such as vascular endothelial cells, epithelial keratinocytes, and macrophage. Finally, we enhanced the biosafety of EMSC spheres by engineering the cells with an inducible suicide gene. Together, we propose topical application of EMSC spheres as an unlimited, quality-assured, safety-enhanced, and noninvasive therapy for wound healing and the CXCL12-CXCR4 axis as a key player in the treatment.
Project description:The process of wound healing in humans is poorly understood. To identify spatiotemporal gene expression patterns during human wound healing, we performed single cell and spatial transcriptomics profiling of human in vivo wound samples.