Project description:Cultured skin substitutes, prepared using keratinocytes, fibroblasts and biopolymers, can facilitate closure of massive burn wounds by increasing the availability of autologous tissue for grafting. However, because they contain only two cell types, skin substitutes cannot replace all of the functions of native human skin. To better understand the physiological and molecular differences between cultured skin substitutes and native skin, we undertook a comprehensive analysis of gene expression in native skin, cultured keratinocytes, cultured fibroblasts, and skin substitutes using Affymetrix gene chip microarrays. Goals: Our analysis focused on identifying gene signatures that were highly characteristic of each cell and tissue type, and those that are regulated by the formation of cultured skin substitute from the individual components. Normalization: We used a normalization and referencing strategy that consisted of BioConductor/RMA Express RMA processing of the entire series of cel files followed by a per gene normalization in which the median value of expression for each gene was derived from the cultured samples only, and this was used as a reference for all samples including the cultured skin substitute. This approach allowed for the identification of genes that were higher and lower-expressed in the cultured skin relative to the individual cell types that were also expressed strongly or weakly in normal skin relative to the median value established by the three cell types. Results Summary:We identified six major clusters of coordinately regulated genes that were the most differentially expressed between groups. These clusters correspond to biomarker pools representing expression signatures for native skin, fibroblasts, keratinocytes, and cultured skin. The expression analysis revealed that entire clusters of genes were either up-regulated or down-regulated upon combination of fibroblasts and keratinocytes in cultured skin grafts. Further, several categories of genes were overexpressed in cultured skin substitutes compared with native skin, including genes associated with hyperproliferative skin or activated keratinocytes. The observed pattern of expression indicates that cultured skin substitutes in vitro, which display a well-differentiated epidermal layer, exhibit skin-like differentiation relative to gene expression patterns in the individual cells. This consists of both the activation of normal skin signature genes and the suppression of keratinocyte and fibroblast signatures. There is also a signature consistent with a hyperproliferative phenotype similar to wounded native skin. Keywords: Cell interaction and co-culture response expression profile
Project description:Cultured skin substitutes, prepared using keratinocytes, fibroblasts and biopolymers, can facilitate closure of massive burn wounds by increasing the availability of autologous tissue for grafting. However, because they contain only two cell types, skin substitutes cannot replace all of the functions of native human skin. To better understand the physiological and molecular differences between cultured skin substitutes and native skin, we undertook a comprehensive analysis of gene expression in native skin, cultured keratinocytes, cultured fibroblasts, and skin substitutes using Affymetrix gene chip microarrays. Goals: Our analysis focused on identifying gene signatures that were highly characteristic of each cell and tissue type, and those that are regulated by the formation of cultured skin substitute from the individual components. Normalization: We used a normalization and referencing strategy that consisted of BioConductor/RMA Express RMA processing of the entire series of cel files followed by a per gene normalization in which the median value of expression for each gene was derived from the cultured samples only, and this was used as a reference for all samples including the cultured skin substitute. This approach allowed for the identification of genes that were higher and lower-expressed in the cultured skin relative to the individual cell types that were also expressed strongly or weakly in normal skin relative to the median value established by the three cell types. Results Summary:We identified six major clusters of coordinately regulated genes that were the most differentially expressed between groups. These clusters correspond to biomarker pools representing expression signatures for native skin, fibroblasts, keratinocytes, and cultured skin. The expression analysis revealed that entire clusters of genes were either up-regulated or down-regulated upon combination of fibroblasts and keratinocytes in cultured skin grafts. Further, several categories of genes were overexpressed in cultured skin substitutes compared with native skin, including genes associated with hyperproliferative skin or activated keratinocytes. The observed pattern of expression indicates that cultured skin substitutes in vitro, which display a well-differentiated epidermal layer, exhibit skin-like differentiation relative to gene expression patterns in the individual cells. This consists of both the activation of normal skin signature genes and the suppression of keratinocyte and fibroblast signatures. There is also a signature consistent with a hyperproliferative phenotype similar to wounded native skin. Experiment Overall Design: The sample series consists of native human skin (NHS) samples isolated from female donors undergoing reduction mammoplasty (breast skin) or abdominoplasty (abdomen skin). Skin samples from donors that were used to establish cultures of fibroblasts (CF) and keratinocytes (CK) were assigned donor numbers in the order they were processed in the laboratory, for example: 633, 634, etc. An additional human skin sample (C-1-Ref) was used only to make RNA as a standard control, and was therefore not assigned a donor number. Cultured skin substitutes (CSS) were prepared using isogenic CF and CK from each donor, and were cultured for 2 weeks in vitro to permit development of a stratified and cornified epidermal layer (confirmed by histology). For microarray analysis, RNA was isolated from intact NHS, from CF and CK in monolayer cultures, and from CSS. Samples are labeled indicating the sample type and donor number; for example, CF633 represents cultured fibroblasts from donor 633. To control for variation between individuals, four donors (= biological replicates) were used for each sample type: NHS, CF, CK, and CSS. Efforts were made to have complete sets of 4 samples from each donor, but intact RNA was not obtainable from 2 of the NHS samples (donors 634 and 651); these were replaced with NHS RNA from similar donors (donors C-1-Ref and 636). To check the fidelity of the microarray analysis, 2 of the RNA samples (CK639 and CSS651) were analyzed in duplicate (= technical replicates)
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:Autologous skin grafting is a standard treatment for skin defects such as burns. No artificial skin substitutes are functionally equivalent to autologous skin grafts. The cultured epidermis lacks the dermis and does not engraft deep wounds. Although reconstituted skin, which consists of cultured epidermal cells on a synthetic dermal substitute, can engraft deep wounds, it requires the wound bed to be well-vascularized and lacks skin appendages. In this study, we successfully generate complete skin grafts with PSC-derived epidermis with appendages on p63 knockout embryos' dermis. Donor PSC-derived keratinocytes encroach the embryos' dermis by eliminating p63 knockout keratinocytes based on cell-extracellular matrix adhesion mediated cell competition. Although the chimeric skin contains allogenic dermis, it is engraftable as long as autologous grafts. Furthermore, we could generate semi-humanized skin segments by human keratinocytes injection into the amnionic cavity of p63 knockout mice embryos. Niche encroachment opens the possibility of human skin graft production in livestock animals.
Project description:In normal skin, interactions between melanocytes and keratinocytes, and between melanocytes and the basal membrane are functionally relevant for maintenance of homeostasis and epidermal melanin unit whose deregulation may trigger a continuous proliferation of the melanocytes. In order to further elucidate the molecular events related to cell-cell and cell-ECM interactions in relation to the biology of melanomas, we analyzed the expression profile of 64 human melanomas, 21 primary samples and 43 independent metastasis.
Project description:RNA sequencing has been performed to investigate the transcriptomic profile of keratinocyte derived from keloid and normal skin tissue. Keratinocytes of low passage (p2-4) were cultured onto T25 flasks until full confluence was reached. Keratinocytes were then harvested by trypsinization using 0.05% trypsin-EDTA and washed in Phosphate Buffered Saline (PBS). RNA was extracted using the RNeasy Mini kit protocol. Samples were then sent to the Australian Genome Research Facility (AGRF) where 1μg of RNA was submitted for next-generation sequencing. Once raw data returned, bioinformatics analyses were conducted. Through RNA-seq and bioinformatics analysis, 252 differentially expressed genes were identified in keloid keratinocytes compared to normal skin keratinocytes. Further gene ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) analyses revealed that changes in tight junctions and dysregulated response to viral infection were associated with keloid epithelia and may be linked to the disease. The results of the transcriptome analysis intimate that keloid derived keratinocytes exhibit an abnormal gene expression profile and the abnormalities in keloid keratinocytes may have an important role in keloid pathogenesis.
Project description:Overexpression of activin by keratinocytes promotes HPV8-induced skin tumorigenesis in mice. Activin-promoted tumorigenesis is mediated via the stroma, specifically by cancer-associated fibroblasts (CAFs). To determine if activin alters the gene expression profile of skin fibroblasts, we performed RNA-sequencing of fibroblasts FACS-sorted from pre-cancerous ear skin of activin overexpressing mice. We found that activin induces a CAF-like gene expression profile of fibroblasts, leading to the upregulation of genes involved in proliferation, migration and cytoskeletal remodeling.
Project description:Patients with the genetic skin blistering disease recessive dystrophic epidermolysis bullosa (RDEB) develop aggressive cutaneous squamous cell carcinoma (cSCC). Metastasis leading to mortality is greater in RDEB than in other patient groups with cSCC. Here we investigate the dermal component in RDEB using mRNA expression profiling to compare cultured fibroblasts isolated from individuals without cSCC and directly from tumor matrix in RDEB and non-RDEB samples. While gene expression of RDEB normal skin fibroblasts resembled that of cancer-associated fibroblasts, RDEB cancer-associated fibroblasts exhibited a distinct and divergent gene expression profile, with a large proportion of the differentially expressed genes involved in matrix and cell adhesion. RDEB cancer-associated fibroblasts conferred increased adhesion and invasion to tumor and non-tumor keratinocytes. Reduction of COL7A1, the defective gene in RDEB, in normal dermal fibroblasts led to increased type XII collagen, thrombospondin-1 and Wnt-5A, while re-expression of wild type COL7A1 in RDEB fibroblasts decreased type XII collagen, thrombospondin- 1, and Wnt-5A expression, reduced tumor cell invasion in organotypic culture, and restricted tumor growth in vivo. Overall our findings demonstrate that matrix composition in patients with RDEB is a permissive environment for tumor development, and type VII collagen directly regulates the composition of matrix proteins secreted by dermal and cancer-associated fibroblasts.
Project description:Patients with the genetic skin blistering disease recessive dystrophic epidermolysis bullosa (RDEB) develop aggressive cutaneous squamous cell carcinoma (cSCC). Metastasis leading to mortality is greater in RDEB than in other patient groups with cSCC. Here we investigate the dermal component in RDEB using mRNA expression profiling to compare cultured fibroblasts isolated from individuals without cSCC and directly from tumor matrix in RDEB and non-RDEB samples. While gene expression of RDEB normal skin fibroblasts resembled that of cancer-associated fibroblasts, RDEB cancer-associated fibroblasts exhibited a distinct and divergent gene expression profile, with a large proportion of the differentially expressed genes involved in matrix and cell adhesion. RDEB cancer-associated fibroblasts conferred increased adhesion and invasion to tumor and non-tumor keratinocytes. Reduction of COL7A1, the defective gene in RDEB, in normal dermal fibroblasts led to increased type XII collagen, thrombospondin-1 and Wnt-5A, while re-expression of wild type COL7A1 in RDEB fibroblasts decreased type XII collagen, thrombospondin- 1, and Wnt-5A expression, reduced tumor cell invasion in organotypic culture, and restricted tumor growth in vivo. Overall our findings demonstrate that matrix composition in patients with RDEB is a permissive environment for tumor development, and type VII collagen directly regulates the composition of matrix proteins secreted by dermal and cancer-associated fibroblasts. 16 samples