Skeletal muscle senescence influences whole organism aging, yet little is known on the relay of pro-longevity signals from muscles to other tissues. We performed an RNAi screen in Drosophila for muscle-released cytokines (?myokines?) regulating lifespan and identified Myoglianin, the homolog of human Myostatin. Myoglianin is induced in skeletal muscles by the transcription factor Mnt and together they constitute an inter-organ signaling module that regulates lifespan, age-related muscle dysfunction, and protein synthesis across aging tissues. Both Mnt and Myoglianin activate already in young age the protective decline in protein synthesis that is typical of old age, while knock-down of Myoglianin impairs this process. Mechanistically, Mnt decreases the expression of nucleolar components in muscles while also decreasing nucleolar size in distant tissues via Myostatin/p38 MAPK signaling. Our results highlight a myokine-dependent inter-organ longevity pathway that coordinates nucleolar function and protein synthesis across aging tissues.
Intertissue control of the nucleolus via a myokine-dependent longevity pathway.
Sex, Specimen part, Treatment
View SamplesAnti-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 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 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 SamplesKeratinocyte (KC) hyper-proliferation and epidermal thickening are characteristic features of psoriasis lesions, but the specific contributions of KCs to plaque formation are not fully understood. This study used RNA-seq to investigate the transcriptome of primary monolayer KC cultures grown from lesional (PP) and non-lesional (PN) biopsies of psoriasis patients and control subjects (NN). Whole skin biopsies from the same subjects were evaluated concurrently. RNA-seq analysis of whole skin identified a larger number of psoriasis-increased differentially expressed genes (DEGs), but analysis of KC cultures identified more PP- and PN-decreased DEGs. These latter DEG sets overlapped more strongly with genes near loci identified by psoriasis genome-wide association studies and were enriched for genes associated with epidermal differentiation. Consistent with this, the frequency of AP-1 motifs was elevated in regions upstream of PN-KC-decreased DEGs. A subset of these genes belonged to the same co-expression module, mapped to the epidermal differentiation complex, and exhibited differentiation-dependent expression. These findings demonstrate a decreased differentiation gene signature in PP/PN-KCs that had not been identified by pre-genomic studies of patient-derived monolayers. This may reflect intrinsic defects limiting psoriatic KC differentiation capacity, which may contribute to compromised barrier function in normal-appearing uninvolved psoriatic skin. Overall design: Samples were obtained from lesional skin of psoriasis patients (PP), uninvolved skin of psoriasis patients (PN), and normal skin from control individuals (NN). RNA was extracted from full-thickness skin biopsies of keratinocytes (KCs) grown as monolayer cutures. Samples were obtained from 4 psoriasis patients (individuals 1 - 4) and 4 control subjects (individuals 5 - 8).
RNA-seq identifies a diminished differentiation gene signature in primary monolayer keratinocytes grown from lesional and uninvolved psoriatic skin.
Specimen part, Subject
View SamplesLassa fever virus is a zoonotic pathogen that plagues the endemic areas of West Africa. Rhesus macaques infected with a related arenavirus, LCMV-WE, serve as a model for Lassa-infection of human beings. Using a dose similar to that expected from a needle-stick, monkeys experience an early pre-viremic phase (day 1-3), a viremic phase with febrile onset (day 4-7), and, like human beings who succumb, they die within two weeks. Our goal was to monitor changes in gene expression that parallel disease progression in an effort to 1) identify genes with altered expression after infection, 2) identify genes that could discriminate between a virulent and non-virulent infection, and 3) identify genes encoding products that could serve as treatment targets for FDA-approved pharmaceuticals. Genes related to all three of these categories have been identified and some have been given preliminary validation by quantitative PCR and proteomic studies. These genes will be valuable candidates for future validation as prognostic biomarkers
Early blood profiles of virus infection in a monkey model for Lassa fever.
No sample metadata fields
View SamplesInverse and erythrodermic psoriasis are rare subtypes of psoriasis. Whereas the former is characterized by shiny erythematous non-scaly plaques in the body folds, the latter has widespread redness with fine scale, covering over 80% of the body-surface area, and can be life-threatening. Both are considered to be clinical subtypes of chronic plaque psoriasis, and often co-exist or evolve from plaque psoriasis (Boyd and Menter, 1989; Omland and Gniadecki, 2015), but the pathogenic mechanisms involved are unknown, and current treatments are frequently unsatisfactory. To assess shared and unique processes between chronic plaque, inverse, and erythrodermic psoriasis we analyzed archived formalin-fixed paraffin-embedded biopsies of clinically and histologically confirmed chronic plaque (n=12), inverse (n=40) and erythrodermic psoriasis cases (n=30) and healthy control skin (n=20) using Affymetrix ST 2.1 Arrays. Compared with healthy skin, psoriatic plaque lesions yielded 2450 differentially expressed genes (DEGs) (FDR, p<0.05), inverse psoriasis lesions yielded 408 DEGs (FDR, p<0.05) and erythrodermic psoriasis lesions yielded 447 DEGs (FDR, p<0.05). In total 294 genes were found to be shared among the three disease subtypes (FDR, p<0.05). While the overlap only accounted for 12% of the DEGs in chronic plaque psoriasis, it accounted for 66% and 72% of DEGs in erythrodermic and inverse psoriasis respectively.
IL-17 Responses Are the Dominant Inflammatory Signal Linking Inverse, Erythrodermic, and Chronic Plaque Psoriasis.
Specimen part, Disease, Disease stage
View SamplesWe identified fibro-inflammatory and keratin gene expression signatures in systemic sclerosis skin.
Dissecting the heterogeneity of skin gene expression patterns in systemic sclerosis.
Age, Specimen part, Race, Subject, Time
View Samples