Project description:A subset of human skin fibroblasts are phagocytic. To investigate the gene expression changes between phagocytosing and non-phagocytosing fibroblasts, fibroblasts were incubated with apoptotic human dermal microvascular endothelial cells expressing green fluorescent protein or no treatment. Treated fibroblasts were then collected after 8 hours and sorted by FACS to identify phagocytic and non-phagocytic fibroblasts. We then performed gene expression profiling analysis using data obtained from RNA-seq of these three groups of cells.
Project description:Activation of fibroblasts and formation of myofibroblasts are essential for granulation tissue formation following injury. In fibrotic reactions, excessive deposition of ECM by the activated fibroblasts determines scar formation and functional failure. Although these events critically depend on the activity of a plethora of growth factors and cytokines, TGFβ1 is a unique player controlling the immune response and proliferation of many cell types. Different cell types contribute to its release and activation, which is also regulated by the interaction with the ECM and by mechanical forces. The aim of this study was to elaborate whether fibroblast-derived TGFβ1 plays a critical role during these processes. The data demonstrate a dynamic expression of TGFβ1 during tissue repair. Cell-specific ablation of Tgfb1 in fibroblasts revealed that deletion of TGFβ1 attenuates bleomycin-induced skin fibrosis and delays maturation of granulation tissue in skin wounds. Absence of fibroblast-derived TGFβ1 induced vascular alterations (less vascular density and branching, hemorrhage) in early wound healing, potentially influenced by coincident alterations in the formation of stable ECM structure. This can be explained by paracrine regulation of endothelial cells or pericytes by fibroblast-released TGFβ1 and by impaired expression of pro-angiogenic factors in TGFβ1-deficient fibroblasts. Our findings provide novel mechanistic insights into the central role of fibroblast-derived TGFβ1 for early stages of tissue repair and fibrosis in the skin.
Project description:Keloids are scars that extend beyond original wounds and are resistant to treatment. In order to improve understanding of the molecular basis of keloid scarring, we have assessed the genomic profiles of keloid fibroblasts and keratinocytes. Skin and scar tissues were obtained for isolation of primary keratinocytes and fibroblasts. Keloid scars were excised from patients undergoing scar excision surgery, normal skin samples were isolated from patients undergoing elective plastic surgery. Primary culters were prepared for keratinocytes and fibroblasts, and were harvested for analysis up to passage three. Nine keloid scars, for adjacent non-lesional keloid skin samples, and three normal skin samples were obtained and cultured. RNA was isolated using RNeasy, and quality verified using an Agilent 2100 Bioanalyzer. Labeling and hybridization to Affymetrix Human Gene 1.0 ST microarray chips was performed by the Vanderbilt Genome Sciences Resource at Vanderbilt University Medical Center.
Project description:Hypertrophic scarring (HS) is characterized by excessive extracellular matrix deposition, matrix metalloprotein gene activation, and fibroblast invasive growth. However, the methylation level of hypertrophic scarring is poorly understood. Genome wide DNA methylation profiling of normal skin and hypertrophic scar. The Illumina Infinium Methylation EPIC BeadChip (850K) was used to obtain DNA methylation profiles across approximately 853,307 CpGs in liquid based scar samples. Samples included 6 normal skin, and 6 hypertrophic scar.
Project description:This SuperSeries is composed of the SubSeries listed below. Project abstract: In adult mammals, skin wound healing has evolved to favor rapid repair through the formation of fibrotic scar. These dermal scars are dysfunctional and may lead to chronic disfigurement and disability, yet the biologic mechanisms that drive fibrosis and prevent tissue regeneration remain unknown. Here, we report that reindeer (Rangifer tarandus) antler velvet exhibits regenerative wound healing, whereas identical full-thickness injury in dorsal back skin of the same animal forms fibrotic scar. This regenerative capacity is retained even following ectopic transplantation of velvet to a scar-forming site, demonstrating that this latent regenerative capacity is innate to velvet cells and independent of local factors derived from the growing antler. Single cell RNA-sequencing of uninjured skin revealed a marked divergence in resting fibroblast transcriptional states and immunomodulatory function. Uninjured velvet fibroblast shared a striking resemblance with human fetal fibroblasts whereas uninjured back skin fibroblasts exhibited an overrepresentation of pro-inflammatory genes resembling adult human fibroblasts. Identical skin injury resulted in site-specific fibroblast polarization; back fibroblasts exacerbated the inflammatory response, whereas velvet fibroblasts adopted an immunosuppressive state and reverted back to a regeneration-competent ground state. Consequently, velvet wounds exhibited an accelerated adoption of anti-inflammatory immune states and an expedited resolution of immune response. This study demonstrates reindeer as a novel comparative mammalian model to study both adult skin regeneration (velvet) and scar formation (back skin) within the same animal. Our study underscores the importance of fibroblast heterogeneity in shaping local immune cell functions that ultimately polarize wound healing outcomes. Purposeful, acute modulation of fibroblast-mediated immune signaling represents an important therapeutic avenue to mitigate scar and improve wound healing.
Project description:In adult mammals, skin wound healing has evolved to favor rapid repair through formation of fibrotic scar. Consequently, skin wounds are dysfunctional and lead to chronic disfigurement and disability, yet the biologic mechanisms that drive fibrosis and prevent tissue regeneration remain unknown. Here, we report that reindeer (Rangifer tarandus) antler velvet exhibits regenerative wound healing, whereas identical full-thickness injury in dorsal back skin forms fibrotic scar. This regenerative capacity is retained even following ectopic transplantation of velvet to a scar-forming site, demonstrating that this latent regenerative capacity is innate to velvet cells and independent of local factors derived from the growing antler. Single cell RNA-sequencing of uninjured skin revealed a marked divergence in resting fibroblast transcriptional states and immunomodulatory function. Uninjured velvet fibroblast shared a striking resemblance with human fetal fibroblasts whereas uninjured back skin fibroblasts exhibited an overrepresentation of pro-inflammatory genes resembling adult human fibroblasts. Identical skin injury resulted in site-specific fibroblast polarization; back fibroblasts exacerbated the inflammatory response, whereas velvet fibroblasts adopted an immunosuppressive state and reverted back to a regeneration-competent ground state. Consequently, velvet wounds exhibited reduced immune infiltrate, accelerated adoption of anti-inflammatory immune states and expedited resolution of immune response. This study demonstrates reindeer as a novel mammalian model to study adult skin regeneration (velvet) and scar formation (back skin) within the same animal. Our study underscores the importance of fibroblast heterogeneity in shaping local immune cell functions that ultimately polarize wound healing outcomes. Purposeful, acute modulation of fibroblast-mediated immune signaling represents an important therapeutic avenue to mitigate scar and improve wound healing.
Project description:In adult mammals, skin wound healing has evolved to favor rapid repair through the formation of fibrotic scar. These dermal scars are dysfunctional and may lead to chronic disfigurement and disability, yet the biologic mechanisms that drive fibrosis and prevent tissue regeneration remain unknown. Here, we report that reindeer (Rangifer tarandus) antler velvet exhibits regenerative wound healing, whereas identical full-thickness injury in dorsal back skin of the same animal forms fibrotic scar. This regenerative capacity is retained even following ectopic transplantation of velvet to a scar-forming site, demonstrating that this latent regenerative capacity is innate to velvet cells and independent of local factors derived from the growing antler. Single cell RNA-sequencing of uninjured skin revealed a marked divergence in resting fibroblast transcriptional states and immunomodulatory function. Uninjured velvet fibroblast shared a striking resemblance with human fetal fibroblasts whereas uninjured back skin fibroblasts exhibited an overrepresentation of pro-inflammatory genes resembling adult human fibroblasts. Identical skin injury resulted in site-specific fibroblast polarization; back fibroblasts exacerbated the inflammatory response, whereas velvet fibroblasts adopted an immunosuppressive state and reverted back to a regeneration-competent ground state. Consequently, velvet wounds exhibited an accelerated adoption of anti-inflammatory immune states and an expedited resolution of immune response. This study demonstrates reindeer as a novel comparative mammalian model to study both adult skin regeneration (velvet) and scar formation (back skin) within the same animal. Our study underscores the importance of fibroblast heterogeneity in shaping local immune cell functions that ultimately polarize wound healing outcomes. Purposeful, acute modulation of fibroblast-mediated immune signaling represents an important therapeutic avenue to mitigate scar and improve wound healing.
Project description:In adult mammals, skin wound healing has evolved to favor rapid repair through the formation of fibrotic scar. These dermal scars are dysfunctional and may lead to chronic disfigurement and disability, yet the biologic mechanisms that drive fibrosis and prevent tissue regeneration remain unknown. Here, we report that reindeer (Rangifer tarandus) antler velvet exhibits regenerative wound healing, whereas identical full-thickness injury in dorsal back skin of the same animal forms fibrotic scar. This regenerative capacity is retained even following ectopic transplantation of velvet to a scar-forming site, demonstrating that this latent regenerative capacity is innate to velvet cells and independent of local factors derived from the growing antler. Single cell RNA-sequencing of uninjured skin revealed a marked divergence in resting fibroblast transcriptional states and immunomodulatory function. Uninjured velvet fibroblast shared a striking resemblance with human fetal fibroblasts whereas uninjured back skin fibroblasts exhibited an overrepresentation of pro-inflammatory genes resembling adult human fibroblasts. Identical skin injury resulted in site-specific fibroblast polarization; back fibroblasts exacerbated the inflammatory response, whereas velvet fibroblasts adopted an immunosuppressive state and reverted back to a regeneration-competent ground state. Consequently, velvet wounds exhibited an accelerated adoption of anti-inflammatory immune states and an expedited resolution of immune response. This study demonstrates reindeer as a novel comparative mammalian model to study both adult skin regeneration (velvet) and scar formation (back skin) within the same animal. Our study underscores the importance of fibroblast heterogeneity in shaping local immune cell functions that ultimately polarize wound healing outcomes. Purposeful, acute modulation of fibroblast-mediated immune signaling represents an important therapeutic avenue to mitigate scar and improve wound healing.
Project description:Mammalian skin wounds heal by forming fibrotic scars. We report that reindeer antler velvet exhibits regenerative wound healing, whereas identical injury to back skin forms scar. This regenerative capacity was retained following ectopic transplantation of velvet to scar-forming sites. Single-cell mRNA/ATAC-Sequencing revealed that while uninjured velvet fibroblasts resembled human fetal fibroblasts, back skin fibroblasts were enriched in pro-inflammatory features resembling adult human fibroblasts. Injury elicited site-specific immune polarization; back skin fibroblasts amplified the immune response, whereas velvet fibroblasts adopted an immunosuppressive state leading to restrained myeloid maturation and hastened immune resolution ultimately enabling myofibroblast reversion to a regeneration-competent state. Finally, regeneration was blunted following application of back skin associated immunostimulatory signals or inhibition of pro-regenerative factors secreted exclusive to velvet fibroblasts. This study highlights a unique model to interrogate mechanisms underlying divergent healing outcomes and nominates both decoupling of stromal-immune crosstalk and reinforcement of pro-regenerative fibroblast programs to mitigate scar.
Project description:To explore the functional difference between CD90+CD39+ and CD90+CD39- fibroblasts in human hypertrophic scar and normal skin, the gene expresson microarray was performed on Live CD49f- E-Cadherin- Lin- CD45- CD31- CD90+ CD39+ and Live CD49f- E-Cadherin- Lin- CD45- CD31- CD90+ CD39- cells sorted from suspension disgested from three human hypertrophic scar samples; and Live CD49f- E-Cadherin- Lin- CD45- CD31- CD90+ CD39+ cells sorted from suspension disgested from three human normal skin samples