Project description:Wound healing is a complex process regulated by various cell types and a plethora of mediators. While interactions between wounded skin and the hair follicles (HFs) could induce HF neogenesis or promote wound healing, it remains unknown whether the wound healing-associated signaling milieu can be manipulated to protect against alopecia, such as chemotherapy-induced alopecia (CIA). Utilizing a well-established neonatal rat model of CIA, we show here that skin wounding protects from alopecia caused by several clinically relevant chemotherapeutic regimens, and that protection is dependent on the time of wounding and hair cycle stage. Gene expression profiling unveiled a significant increase in interleukin-1 beta (IL-1β) mediated signaling by skin wounding. Subsequently, we showed that IL-1β is sufficient and indispensable for mediating the CIA-protective effect. Administration of IL-1β alone to unwounded rats exhibited local CIA protection while IL-1β neutralization abrogated CIA protection by wounding. Mechanistically, IL-1β retarded postnatal HF morphogenesis, making HFs at the wound sites or IL-1β treated areas damage-resistant while the rats developed total alopecia elsewhere. We conclude that wound healing switches the cutaneous cytokine milieu to an IL-1β-dominated state thus retarding HF growth progression and rendering the HFs resistant to chemotherapy agents. In the future, manipulation of HF progression through interfering with the IL-1β signaling milieu may provide therapeutic benefits to a variety of conditions, from prevention of CIA to inhibition of hair growth and treatment of hirsutism. In this experiment, we used the Rat MI-Ready array comprised of over 34,000 transcript probes for gene and alternative splice products in ENSEMBL release 37 to profile gene expression changes during acute wound healing in rat skin. 16,198 Selected rat probes were above threshold in at least one group. 3,239 significant genes were found (FDR < 0.1).
Project description:The aim of this experiment was measure the influence of age on cutaneous wound healing using human subjects. Increaded age has been associated with delayed wound healing in mouse models and in humans. Gene expression was compared between excisional biopsy wounds from young and old subjects.
Project description:To determine whether dural fibroblasts (DuF) under IL-1β-mediated wound conditions, release pro-angiogenic factors, and promote angiogenic properties in human endothelial cells (ECs). DuF were stimulated by pro-inflammatory cytokines interleukin (IL)-1β, and transcriptome sequencing was then used to identify the differentially expressed genes in the DuF with/without IL-1β stimulation (DuFCon/DuFIL1b)
Project description:Pyroptosis is a lytic cell death mode that helps limit the spread of infections and is also linked to pathology in sterile inflammatory diseases and autoimmune diseases. During pyroptosis, inflammasome activation and the engagement of caspase-1 lead to cell death, along with the maturation and secretion of the inflammatory cytokine interleukin 1β (IL-1β). The dominant effect of IL-1β in promoting tissue inflammation has clouded the potential influence of other factors released from pyroptotic cells. Here, using a system where macrophages are induced to undergo pyroptosis without IL-1β/⍺ release (denoted Pyro-1), we uncover unexpected beneficial effects of the Pyro-1 secretome. First, we noted that the Pyro-1 supernatants upregulated gene signatures linked to migration, cellular proliferation, and wound healing. Consistent with this gene signature, Pyro-1 supernatants boosted migration of primary fibroblasts and macrophages, as well as faster wound closure in vitro, and improved tissue repair in vivo. In mechanistic studies, lipidomics and metabolomics of the Pyro-1 supernatants identified the presence of both oxylipins and metabolites, linking them to pro-wound healing effects. Focusing specifically on the oxylipin prostaglandin E2 (PGE2), we find that PGE2 synthesis is induced de novo during pyroptosis, downstream of caspase-1 activation, and COX2 activity; further, PGE2 synthesis occurs late in pyroptosis, with its release dependent on Gasdermin D pores opened during pyroptosis. As for the pyroptotic metabolites, they link to immune cell infiltration into the wounds, and polarization to CD301+ macrophages. Collectively, these data advance the concept that the pyroptotic secretome 1 Mehrotra et al., Page No. possesses oxylipins and metabolites with tissue repair properties that may be harnessed therapeutically.
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: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:To identify the candidate miRNAs that might compromise wound healing and contribute to the age-associated delay in wound repair, global miRNA profiling was performed in mouse back telogen skin of young (8-week-old) and aged (2-year-old) animals.
Project description:Healing of the cutaneous wound requires macrophage recruitment at the sites of injury, where chemotactic migration of macrophages toward the wound is regulated by local inflammation. Recent studies suggest a positive contribution of DNA methyltransferase 1 (Dnmt1) to macrophage pro-informatory responses; however, its role in regulating macrophage motility remains unknown. In this study, myeloid-specific depletion of Dnmt1 in mice promoted cutaneous wound healing and de-suppressed the lipopolysaccharides (LPS)-inhibited macrophage motility. Dnmt1 inhibition in macrophages eliminated the LPS-stimulated changes in cellular mechanical properties in terms of elasticity and viscoelasticity. LPS increased the cellular accumulation of cholesterol in a Dnmt1-depedent manner; cholesterol content determined cellular stiffness and motility. Lipidomic analysis indicated that Dnmt1 inhibition altered the cellular lipid homeostasis, probably through down-regulating the expression of cluster of differentiation 36 CD36 (facilitating lipid influx) and up-regulating the expression of ATP-binding cassette transporter ABCA1 (mediating lipid efflux) and sterol O-acyltransferase 1 SOAT1 (also named ACAT1, catalyzing the esterification of cholesterol). Our study revealed a Dnmt1-dependent epigenetic mechanism in the control of macrophage mechanical properties and the related chemotactic motility, indicating Dnmt1 as both a marker of diseases and a potential target of therapeutic intervention for wound healing.
Project description:Bone morphogenetic protein (BMP) signalling plays a key role in the control of skin development and postnatal remodelling by regulating keratinocyte proliferation, differentiation and apoptosis. To study the role of BMPs in wound-induced epidermal repair, we used transgenic mice overexpressing the BMP downstream component Smad1 under the control of a K14 promoter as an in vivo model, as well as ex vivo and in vitro assays. K14-caSmad1 mice exhibited retarded wound healing associated with significant inhibition of proliferation and increased apoptosis in healing wound epithelium. Furthermore, microarray and qRT-PCR analyses revealed decreased expression of a number of cytoskeletal/cell motility-associated genes including wound-associated keratins (Krt16, Krt17) and Myo5a, in the epidermis of K14- caSmad1 mice versus wild-type controls during wound healing. BMP treatment significantly inhibited keratinocyte migration ex vivo, and primary keratinocytes of K14-caSmad1 mice showed retarded migration compared to wild-type controls. Finally, siRNA-mediated silencing of Bmpr-1B in primary mouse keratinocytes accelerated cell migration and was associated with increased expression of Krt16, Krt17 and Myo5a compared to controls. Thus, this study demonstrates that BMPs inhibit keratinocyte proliferation, cytoskeletal organization and migration in regenerating skin epithelium during wound healing, and raises a possibility for using BMP antagonists for the management of chronic wounds. Two-condition experiment, Wild type vs. Smad1 overexpressing mice. Biological replicates: 2 replicates.
Project description:Wound priming in epidermal Lrig1 stem cell progeny leads to a more efficient response to future injuries. To understand if primed progenitors maintain during aging the transcriptional program acquired during wound healing in young age, we performed single cell RNA-Seq of Lrig1 stem cell progeny 40 weeks after injury.