Anti-TNF-alpha therapy has made a significant impact on the treatment of psoriasis. Despite being designed to neutralize TNF-alpha activity, the mechanism of action of these agents in the resolution of psoriasis remains unclear. The aim of this study was to better understand the mechanism of action of etanercept by examining very early changes in the lesional skin of psoriasis patients. 20 chronic plaque psoriasis patients were enrolled and received 50mg etanercept twice weekly. Skin biopsies were obtained before treatment and on days 1, 3, 7 and 14 post-treatment. Skin mRNA expression was analysed by microarray.
Early tissue responses in psoriasis to the antitumour necrosis factor-α biologic etanercept suggest reduced interleukin-17 receptor expression and signalling.
Specimen part, Disease, Subject
View SamplesThe Mrp8 and Mrp14 proteins (calprotectin) accumulate within tissues during aging and may contribute to chronic inflammation. To address this possibility, we evaluated calprotectin-deficient Mrp14-KO and wild-type (WT) mice at 5 and 24 months of age. However, there was no evidence that age-related inflammation is blunted in KO mice. Inflammation makers were in fact elevated in livers from old KO mice, and microarray analysis revealed more consistent elevation of genes specifically expressed by B-cells and T-cells. Adipose-specific genes, however, were less consistently elevated in aged KO mice, suggesting an anti-steatosis effect of Mrp8/14 deficiency. Consistent with this, genes decreased by the anti-steatosis agent SRT1720 were decreased in old KO compared to old WT mice. Expression of lipid metabolism genes was altered in KO mice at 5 months of age, along with genes associated with development, biosynthesis and immunity. These early-age effects of Mrp8/14 deficiency, in the absence of any external stressor, were unexpected. Taken together, our findings demonstrate a pro-steatosis rather than pro-inflammatory role of calprotectin within the aging liver. This appears to reflect a developmental-metabolic phenotype of Mrp14-KO mice that is manifest at a young age in the absence of pro-inflammatory stimuli.
Deficiency of myeloid-related proteins 8 and 14 (Mrp8/Mrp14) does not block inflammaging but prevents steatosis.
Specimen part
View SamplesBackground: Skin aging is associated with intrinsic processes that compromise structure of the extracellular matrix while promoting loss of functional and regenerative capacity. These processes are accompanied by a large-scale shift in gene expression, but underlying mechanisms are not understood and conservation of these mechanisms between humans and mice is uncertain. Results: We used genome-wide expression profiling to investigate the aging skin transcriptome. In humans, age-related shifts in gene expression were sex-specific. In females, aging increased expression of transcripts associated with T-cells, B-cells and dendritic cells, and decreased expression of genes in regions with elevated Zeb1, AP-2 and YY1 motif density. In males, however, these effects were contrasting or absent. When age-associated gene expression patterns in human skin were compared to those in tail skin from CB6F1 mice, overall human-mouse correspondence was weak. Moreover, inflammatory gene expression patterns were not induced with aging of mouse tail skin, and well-known aging biomarkers were in fact decreased (e.g., Clec7a, Lyz1 and Lyz2). These unexpected patterns and weak human-mouse correspondence may be due to decreased abundance of antigen presenting cells in mouse tail skin with age. Conclusions: Aging is generally associated with a pro-inflammatory state, but we have identified an exception to this pattern with aging of CB6F1 mouse tail skin. Aging therefore does not uniformly heighten inflammatory status across all mouse tissues. Furthermore, we identified both intercellular and intracellular mechanisms of transcriptome aging, including those that are sex- and species-specific.
Meta-profiles of gene expression during aging: limited similarities between mouse and human and an unexpectedly decreased inflammatory signature.
Sex, Age, Specimen part
View SamplesSystemic sclerosis (SSc) is a rare but devastating disease of fibrosis impacting the dermis and multiple organ systems. The prevalence ranges from 4 to 489 cases per million individuals with ten year mortality rates reported around 18 percent. Survival is related to the extent of skin involvement, yet the precise mechanisms driving skin fibrosis in SSc remain unknown. In this study, we analyzed the shared and unique transcriptomic profiles of SSc and normal keratinocytes.
Scleroderma keratinocytes promote fibroblast activation independent of transforming growth factor beta.
Specimen part, Disease, Disease stage
View SamplesWhether epidermal factors play a primary role in immune-mediated skin diseases such as psoriasis is unknown. We now show that the pro-differentiation transcription factor Grainyhead-like 3 (GRHL3), essential during epidermal development but dispensable in adult skin homeostasis, is required for barrier repair after adult epidermal injury. Consistent with activation of a GRHL3-regulated repair pathway in psoriasis, we find GRHL3 up-regulation in lesional skin where GRHL3 binds known epidermal differentiation gene targets. Furthermore, we show the functionality of this pathway in the Imiquimod mouse model of immune-mediated epidermal hyperplasia where loss of Grhl3 exacerbates the epidermal damage response, conferring greater sensitivity to disease induction, delayed resolution of epidermal lesions, and resistance to anti-IL-22 therapy. ChIP-seq and gene expression profiling studies show that while GRHL3 regulates differentiation genes both in development and during repair from immune-mediated damage, it targets distinct sets of genes in the two processes. In particular, GRHL3 suppresses a number of alarmin and other pro-inflammatory genes after immune injury. This study identifies a GRHL3-regulated epidermal barrier repair pathway that suppresses disease initiation and helps resolve existing lesions in immune-mediated epidermal hyperplasia.
A GRHL3-regulated repair pathway suppresses immune-mediated epidermal hyperplasia.
Sex, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
GRHL3 binding and enhancers rearrange as epidermal keratinocytes transition between functional states.
Specimen part, Cell line
View SamplesIn a transcriptome study of psoriatic (PP) vs. normal (NN) skin, we found a co-expressed gene module (N5) enriched 11.5-fold for lipid biosynthetic genes. We also observed fewer visible hairs in PP skin, compared to uninvolved (PN) or NN skin (p<0.0001). To ask whether these findings might be due to abnormalities of the pilosebaceous unit, we carried out 3D morphometric analysis of paired PP and PN biopsies. Sebaceous glands (SG) were markedly atrophic in PP vs. PN skin (91% average reduction in volume, p=0.031). Module N5 genes were strongly downregulated in PP vs. NN skin (fold-change [FC] < 0.25, 44.4-fold), and strongly up-regulated in sebaceous hyperplasia (SH, FC > 4, 54.1-fold). The intersection of PP-downregulated and SH-upregulated gene lists generated a gene expression signature consisting solely of module N5 genes, whose expression in PP vs. NN skin was inversely correlated with the signature of IL17-stimuated keratinocytes. Despite loss of visible hairs, morphometry identified elongated follicles in PP vs. PN skin (average 1.7 vs. 1.2 Jm, p=0.020). These results document SG atrophy in non-scalp psoriasis, identify a cytokine-regulated set of SG signature genes, and suggest that loss of visible hair in PP skin may result from abnormal SG function.
Sebaceous Gland Atrophy in Psoriasis: An Explanation for Psoriatic Alopecia?
Specimen part, Disease, Disease stage
View SamplesThe genomic mechanisms underlying progressive, irreversible cell lineage commitments and differentiation, which include large scale chromatin re-organization, transcription factor binding, and chromatin modifications, have been well defined. However, we know little about the chromatin changes during transitions between transient cell states such as cell migration. Here we demonstrate the formation of unique complements of typical enhancers and super-enhancers as human progenitor keratinocytes either differentiate or migrate. Unique super-enhancers for each cellular state are linked to gene expression that confer functions associated with each cell state, and sequence variants associated with skin diseases are enriched within super-enhancers. GRHL3, a factor that promotes both differentiation and migration, exhibits prominent super-enhancer interactions in differentiating keratinocytes, while during migration, it preferentially binds to promoters along with REST, repressing the expression of migration inhibitors. Key epidermal differentiation transcription factor genes, including GRHL3, are located within super-enhancers, and many of these transcription factors in turn bind to and regulate super-enhancers. Of note, GRHL3 also represses the formation of a number of progenitor and non-keratinocyte super-enhancers in differentiating keratinocytes. Thus, coordinated GRHL3 binding and enhancer rearrangements regulate the functional states of keratinocytes.
GRHL3 binding and enhancers rearrange as epidermal keratinocytes transition between functional states.
Specimen part, Cell line
View SamplesThe genomic mechanisms underlying progressive, irreversible cell lineage commitments and differentiation, which include large scale chromatin re-organization, transcription factor binding, and chromatin modifications, have been well defined. However, we know little about the chromatin changes during transitions between transient cell states such as cell migration. Here we demonstrate the formation of unique complements of typical enhancers and super-enhancers as human progenitor keratinocytes either differentiate or migrate. Unique super-enhancers for each cellular state are linked to gene expression that confer functions associated with each cell state, and sequence variants associated with skin diseases are enriched within super-enhancers. GRHL3, a factor that promotes both differentiation and migration, exhibits prominent super-enhancer interactions in differentiating keratinocytes, while during migration, it preferentially binds to promoters along with REST, repressing the expression of migration inhibitors. Key epidermal differentiation transcription factor genes, including GRHL3, are located within super-enhancers, and many of these transcription factors in turn bind to and regulate super-enhancers. Of note, GRHL3 also represses the formation of a number of progenitor and non-keratinocyte super-enhancers in differentiating keratinocytes. Thus, coordinated GRHL3 binding and enhancer rearrangements regulate the functional states of keratinocytes.
GRHL3 binding and enhancers rearrange as epidermal keratinocytes transition between functional states.
Specimen part, Cell line
View SamplesThe genomic mechanisms underlying progressive, irreversible cell lineage commitments and differentiation, which include large scale chromatin re-organization, transcription factor binding, and chromatin modifications, have been well defined. However, we know little about the chromatin changes during transitions between transient cell states such as cell migration. Here we demonstrate the formation of unique complements of typical enhancers and super-enhancers as human progenitor keratinocytes either differentiate or migrate. Unique super-enhancers for each cellular state are linked to gene expression that confer functions associated with each cell state, and sequence variants associated with skin diseases are enriched within super-enhancers. GRHL3, a factor that promotes both differentiation and migration, exhibits prominent super-enhancer interactions in differentiating keratinocytes, while during migration, it preferentially binds to promoters along with REST, repressing the expression of migration inhibitors. Key epidermal differentiation transcription factor genes, including GRHL3, are located within super-enhancers, and many of these transcription factors in turn bind to and regulate super-enhancers. Of note, GRHL3 also represses the formation of a number of progenitor and non-keratinocyte super-enhancers in differentiating keratinocytes. Thus, coordinated GRHL3 binding and enhancer rearrangements regulate the functional states of keratinocytes.
GRHL3 binding and enhancers rearrange as epidermal keratinocytes transition between functional states.
Specimen part, Cell line
View Samples