Single-cell analysis reveals transcriptomic difference between human hypertrophic scar and keloid
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ABSTRACT: Background Hypertrophic scars and keloids are both pathological scars with similar appearance and pathological features. Currently, the differential diagnosis of the two mainly depends on the subjective judgment of physicians, and there is a lack of objective diagnostic indicators and treatment methods. Objectives To provide single-cell level evidence and new approaches for the differential diagnosis and clinical treatment of hypertrophic scars and keloids. Methods Single-cell RNA sequencing (scRNA-seq) was performed on a hypertrophic scar and a keloid tissue from the same patient to compare the differences in the cellular and tissue microenvironments of the two conditions. Results ScRNA-seq results depicted the distribution of cell subpopulations and different microenvironments between hypertrophic scars and keloids. Conclusions The results of the analysis showed significant differences in cell subcluster distribution and cell communication between hypertrophic scars and keloids. This study demonstrated the potential of scRNA-seq to differentiate the two conditions and provide a new approach to refine differential diagnosis and a possible target for therapeutic research.
Project description:Scars are a heterogeneous disease including normotrophic scars, hypertrophic scars, and keloids. Of these lesions, keloids are a distinct subtype from any other type of scar because clinically, it causes pain, itching, or tenderness, causing life discomfort and characteristically irreversible. Therefore, for accurate diagnosis and treatment of keloids, it is essential to identify keloid-specific genes. However, in previous studies, keloids were compared with controls such as scar-free normal skin. In these studies, general scar-related genes were likely to be chosen rather than keloid-specific genes. In this study, we acquired transcriptomic profiles of normotrophic scars, hypertrophic scars, and keloids from formalin-fixed paraffin-embedded human skin samples using high-throughput RNA-sequencing techniques. We compared the transcriptome profile of keloids with those of other scar lesions to select for highly accurate keloid-specific genes and pathways. The results revealed that genes related with several biological processes such as sensory/visual perception are upregulated strongly in keloids, whereas genes related with activation of immune response were downregulated remarkably in keloids. Furthermore, the biological process of extracellular matrix organization was highlighted in both hypertrophic scars and keloids. In conclusion, our study provides insight into the pathogenesis of keloids distinct from other scar lesions as well as potential keloid-specific biomarkers.
Project description:We hypothesize that, the mTOR pathway is a dominant pathway in cultured keloid and hypertrophy scar fibriblasts compared to normal skin cells. Certain pathway changes can be detected after medication treatment. Global gene expression in RNA samples from rapamycin and tacrolimus treated fibroblasts (from normal skin and hypertrophic scars, keloid scars) is assayed to study the possibility to use mTOR inhibitors as potential drug to treat abnormal scarring. We investigated the difference between normal wound healing and hypertrophic scars and keloids as well.
Project description:Keloid scars is a pathologic fibro-proliferative disorders of the skin, which exhibit abnormal phenotypes including fibroblasts proliferation and collagen deposits. There have been several treatments of keloids including conventional surgical therapies and adjuvant therapies, but a high recurrence rate of keloids was also observed after treatment. Quantitative proteomics approach has been proved an efficient approach to investigate pathological mechanism and novel biomarkers. In this study, we present a label-free quantitative proteomics analysis to explore differential protein expression profiles in normal skin and keloid scar tissues based on nano-liquid chromatography and tandem mass spectrometry (Nano-LC–MS/MS). The study results displayed a more comprehensive keloid protein expression landscape and provided novel pathological insight of keloid.
Project description:To uncover the underlying pathophysiology of keloids, we used two technologies, single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST). we focused on the molecular signature of keloids. In this study, we provide the comprehensive transcriptomic atlas of keloids and its matched spatial information, essential to understanding intercellular crosstalk in the skin microenvironments.
Project description:Fibrosis is vaguely described as connective tissue deposition that can be excessive in pathological conditions. This suggests a quantitative spectrum of fibrosis wherein there can be more or less extracellular matrix (ECM), which in the context of a repairing skin wound could reflect the range from normal scar to keloid. This depiction, however, does not encompass the potential qualitative differences between normal and pathological scars. In keloids, the markedly different physical (hard and dense) and histological (hyalinization) characteristics compared to normal scars indicate an altered and inappropriate matrix, rather than simply too much. With this quantitative discovery-based proteomics we provide a thorough molecular description of keloid lesions relative to normal scars, which is an essential step towards our understanding of this problem.
Project description:Keloids are benign tumors of the dermis that form during a protracted wound healing process. Susceptibility to keloid formation occurs predominantly in people of African and Asian descent. The key alteration(s) responsible for keloid formation has not been identified and there is no satisfactory treatment for this disorder. The altered regulatory mechanism is limited to dermal wound healing, although several diseases characterized by an exaggerated response to injury are prevalent in individuals of African ancestry. We have observed a complex pattern of phenotypic differences in keloid fibroblasts grown in standard culture medium or induced by hydrocortisone. In this study Affymetrix-based microarray was performed on RNA obtained from fibroblasts cultured from normal scars and keloids grown in the absence and presence of hydrocortisone. We observed differential regulation of approximately 500 genes of the 38,000 represented on the Affymetrix chip. Of particular interest was increased expression of several IGF-binding and IGF-binding related proteins and decreased expression of a subset of Wnt pathway inhibitors and multiple IL-1-inducible genes. Increased expression of CTGF and IGFBP-3 was observed in keloid fibroblasts only in the presence of hydrocortisone. These findings support a role for multiple fibrosis-related pathways in the pathogenesis of keloids Keywords: cell-type comparison, drug treatment comparison Cell cultures were initiated from human biopsy material from normal dermal scars and keloids of adult males and females. Experimental cultures were derived from the first passage of cells thawed from liquid nitrogen. Cultures of fibroblasts from samples were grown with or without 1.5 micromolar hydrocortisone. RNA from each cell strain was isolated from three independent cell cultures and pooled, then run on an Affymetrix Human Genome U133 Plus 2.0 GeneChip.
Project description:Pathological scarring is a fibroproliferative disorder characterised by abnormal fibroblast function and excessive deposition of extracellular matrix. In this study, based on the results of preliminary single-cell sequencing, we identified an enriched fibroblast subpopulation in keloids, which highly expresses TAGLN. In this study, we investigated the roles of TAGLN in the pathogenesis of pathological scars, respectively. And functional assays revealed that downregulation of TAGLN inhibited the motility activity and secretory functions of pathological scar fibroblasts, including invasion, migration, contraction and collagen secretion. We identified downstream targets of TAGLN by RNA-seq results analysis and further validation in. This study provides new perspectives for understanding pathological scarring and possible targets for clinical treatment.
Project description:After disruption of the skin, fibroblasts along wound edges are constantly exposed to high levels of stress, resulting in increased collagen synthesis and decreased apoptosis. Emerge evidences shows that, the hypertrophic scars tissue fibrosis phenomena are original from the intrinsic cellular mechanical stretch. Traditional glucocorticoids on hypertrophic scarring have been performed for 30 years, utilizing for their anti-inflammatory, anti-allergenic and immunomodulatory effects and for their well-established, pro-apoptotic effects on hematological malignancies. To explore effects of glucocorticoid triamcinolone acetonide for responses to mechanical stress in hypertrophic scars fibroblasts (HSFB), we performed microarrays to explore the differential gene expression.
Project description:Despite recent advances in understanding skin scarring, mechanisms triggering hypertrophic scar formation are still poorly understood. In the present study we performed single-cell sequencing of mature human hypertrophic scars and developing scars in mice. Compared to normal skin, we found significant differences in gene expression in most cell types present in scar tissue. Fibroblasts (FBs) showed the most prominent alterations in gene expression, displaying a distinct fibrotic signature. By comparing genes upregulated in murine FBs during scar development with genes highly expressed in mature human hypertrophic scars, we identified a group of serine proteases, tentatively involved in scar formation. Two of them, dipeptidyl-peptidase 4 (DPP4) and urokinase (PLAU), were further analyzed in functional assays, revealing a role in TGFβ1-mediated myofibroblast differentiation and over-production of components of the extracellular matrix (ECM) without interfering with the canonical TGFβ1 -signaling pathway. In this study, we delineate the genetic landscape of hypertrophic scars and present new insights into mechanisms involved in hypertrophic scar formation. Our data suggest the use of serine protease inhibitors for the treatment of skin fibrosis.