Psoriasis is a chronic inflammatory skin disease of unknown etiology. Although macrophages and dendritic cells (DCs) have been proposed to drive the psoriatic cascade, their largely overlapping phenotype hampered studying their respective role. Topical application of Imiquimod, a Toll-like receptor 7 agonist, induces psoriasis in patients and psoriasiform inflammation in mice. We showed that daily application of Imiquimod for 14 days recapitulated both the initiation and the maintenance phase of psoriasis. Based on our ability to discriminate Langerhans cells (LCs), conventional DCs, monocytes, monocyte-derived DCs and macrophages in the skin, we characterized their dynamics during both phases of psoriasis. During the initiation phase, neutrophils infiltrated the epidermis whereas monocytes and monocyte-derived DCs were predominant in the dermis. During the maintenance phase, LCs and macrophage numbers increased in the epidermis and dermis, respectively. LC expansion resulted from local proliferation, a conclusion supported by transcriptional analysis. Continuous depletion of LCs during the course of Imiquimod treatment aggravated chronic psoriatic symptoms as documented by an increased influx of neutrophils and a stronger inflammation. Therefore, by developing a mouse model that mimics the human disease more accurately, we established that LCs play a negative regulatory role during the maintenance phase of psoriasis.
Dynamics and Transcriptomics of Skin Dendritic Cells and Macrophages in an Imiquimod-Induced, Biphasic Mouse Model of Psoriasis.
Specimen part, Treatment
View SamplesAnalysis of stratified epidermal cultures treated with IL-1a, IL-1F5, IL-1F6, IL-1F8 and IL-1F9 to determine the effects of these cytokines at 24h. Results provide insight into the role of IL-1 family cytokines in the pathogenesis of psoriasis.
IL-1F5, -F6, -F8, and -F9: a novel IL-1 family signaling system that is active in psoriasis and promotes keratinocyte antimicrobial peptide expression.
Specimen part, Treatment
View SamplesDevelopment of a suitable mouse model would facilitate the investigation of pathomechanisms underlying human psoriasis and would also assist in development of therapeutic treatments. However, while many psoriasis mouse models have been proposed, no single model recapitulates all features of the human disease, and standardized validation criteria for psoriasis mouse models have not been widely applied. In this study, whole-genome transcriptional profiling is used to compare gene expression patterns manifested by human psoriatic skin lesions with those that occur in five psoriasis mouse models (K5-Tie2, imiquimod, K14-AREG, K5-Stat3C and K5-TGFbeta1). While the cutaneous gene expression profiles associated with each mouse phenotype exhibited statistically significant similarity to the expression profile of psoriasis in humans, each model displayed distinctive sets of similarities and differences in comparison to human psoriasis. For all five models, correspondence to the human disease was strong with respect to genes involved in epidermal development and keratinization. Immune and inflammation-associated gene expression, in contrast, was more variable between models as compared to the human disease. These findings support the value of all five models as research tools, each with identifiable areas of convergence to and divergence from the human disease. Additionally, the approach used in this paper provides an objective and quantitative method for evaluation of proposed mouse models of psoriasis, which can be strategically applied in future studies to score strengths of mouse phenotypes relative to specific aspects of human psoriasis.
Genome-wide expression profiling of five mouse models identifies similarities and differences with human psoriasis.
Specimen part
View SamplesSkin conventional dendritic cells (cDC) exist as two distinct subsets, cDC1 and cDC2, which maintain the balance of immunity to pathogens and tolerance to self and microbiota. Here we examined the roles of dermal cDC1 and cDC2 during bacterial infection, notably Propionibacterium acnes (P. acnes). cDC1, but not cDC2, regulated the magnitude of the immune response to P. acnes in the murine dermis by controlling neutrophil recruitment to the inflamed site and survival and function therein. Single-cell mRNA sequencing revealed that this regulation relied on secretion of the cytokine VEGFa by a minor subset of activated EpCAM+CD59+Ly6D+ cDC1. Neutrophil recruitment by dermal cDC1 was also observed during S. aureus, BCG or E. coli infection, as well as in a model of bacterial insult in human skin. Thus, skin cDC1 are essential regulators of the innate response in cutaneous immunity, with roles beyond classical antigen presentation. Overall design: Examined the effect of cDC1 (CD103+DC) depletion on neutrophils infiltrating the skin during P. acnes infection.
A Subset of Type I Conventional Dendritic Cells Controls Cutaneous Bacterial Infections through VEGFα-Mediated Recruitment of Neutrophils.
Specimen part, Treatment, Subject
View SamplesDrosophila melanogaster expresses three classes of small RNAs, which are classified according to their mechanisms of biogenesis. MicroRNAs are ~22-23-nt, ubiquitously expressed small RNAs that are sequentially processed from hairpin-like precursors by Drosha/Pasha and Dcr-1/Loquacious complexes. MicroRNAs usually associate with AGO1 and regulate the expression of protein-coding genes. Piwi-interacting RNAs (piRNAs) of ~24-28-nt associate with Piwi-family proteins and can arise from single-stranded precursors. piRNAs function in transposon silencing and are mainly restricted to gonadal tissues. Endo-siRNAs are found in both germline and somatic tissues. These ~21-nt RNAs are produced by a distinct Dicer, Dcr-2, and do not depend on Drosha/Pasha complexes. They predominantly bind to AGO2 and target both mobile elements and protein-coding genes. Surprisingly, a subset of endo-siRNAs strongly depend for their production on the dsRNA-binding protein Loquacious (Loqs), thought generally to be a partner for Dcr-1 and a co-factor for miRNA biogenesis. Endo-siRNA production depends on a specific Loqs isoform, Loqs-PD, which is distinct from the one, Loqs-PB, required for the production of microRNAs. Paralleling their roles in the biogenesis of distinct small RNA classes, Loqs-PD and Loqs-PB bind to different Dicer proteins, with Dcr-1/Loqs-PB complexes and Dcr-2/Loqs-PD complexes driving microRNA and endo-siRNA biogenesis, respectively. Small RNA profiling by high throughput sequencing Overall design: Total RNA was isolated using Trizol reagent (Invitrogen) and size-fractionated by PAGE into 19-24nt. These were independently processed and sequenced using the Illumina GAII platform. In total, six libraries were analyzed.
Processing of Drosophila endo-siRNAs depends on a specific Loquacious isoform.
Cell line, Subject
View SamplesMind-body practices that elicit the relaxation response (RR) have been used worldwide for millennia to prevent and treat disease. The RR is believed to be the counterpart to stress response and is characterized by decreased oxygen consumption, increased exhaled nitric oxide, and reduced psychological distress. Individuals experiencing chronic psychological stress have the opposite pattern of physiology and a characteristic transcriptional profile. We hypothesized that consistent, long-term practice of RR techniques results in characteristic changes in gene expression. We tested this hypothesis by assessing the transcriptional profile of whole blood in healthy, long-term practitioners of daily RR practice (group M) in comparison to healthy controls (group N1). The signature obtained has been validated on new subject data.
Genomic counter-stress changes induced by the relaxation response.
No sample metadata fields
View SamplesHyperglycemic memory is part of the pathogenesis of diabetic retinopathy. We established a novel mouse model of intermediate-term hyperglycemic memory and demonstrated that changes in gene expression and microvascular damage in the neurovascular unit of the diabetic retina persist after euglycemic reentry, indicating memory.
Hyperglycaemic memory affects the neurovascular unit of the retina in a diabetic mouse model.
Specimen part, Disease
View SamplesThe signaling pathways orchestrating both the evolution and development of language in the human brain remain unknown. To date, the transcription factor FOXP2 is the only gene implicated in Mendelian forms of human speech and language dysfunction1,2. It has been proposed, that the amino acid composition in the human variant of FOXP2 has undergone accelerated evolution, and this change occurred around the time of language emergence in humans3,4. However, this remains controversial, and whether the acquisition of these amino acids in human FOXP2 has any functional consequence in human neurons remains untested. Here, we demonstrate that these two amino acids confer new functionality in terms of differential transcriptional regulation, and extend these observations to in vivo brain, showing that several of the differential FOXP2 targets significantly overlap with genes different between human and chimpanzee brain. We also identify novel relationships among the differentially expressed genes with additional critical regulators of neuronal development. These data provide support for the functional relevance of changes that occur on the human lineage by showing that the two amino acids unique to human FOXP2 can lead to significant differences in gene expression patterns across brain evolution, with direct consequences for human brain development and disease. Since FOXP2 has an important role in the use of language in humans, the identified targets may have a critical function in the development and evolution of language circuitry in humans.
Human-specific transcriptional regulation of CNS development genes by FOXP2.
Specimen part, Cell line
View SamplesA case of transcriptional gene silencing, originally observed in tetraploid Arabidopsis plants, created an epiallele resistant to many mutations or inhibitor treatments that activate other suppressed genes. This raised the question about the molecular basis of this extreme stability.
Cooperation of multiple chromatin modifications can generate unanticipated stability of epigenetic States in Arabidopsis.
Specimen part
View SamplesHematopoietic stem cells (HSCs) are identified by their ability to sustain prolonged blood cell production in vivo, although recent evidence suggests that durable self-renewal (DSR) is shared by HSC subtypes with distinct self-perpetuating differentiation programs. Net expansions of DSR-HSCs occur in vivo, but molecularly defined conditions that support similar responses in vitro are lacking. We hypothesized that this might require a combination of factors that differentially promote HSC viability, proliferation and self-renewal. We now demonstrate that HSC survival and maintenance of DSR potential is variably supported by different Steel factor (SF)-containing cocktails with similar HSC-mitogenic activities. In addition, stromal cells produce other factors, including nerve growth factor and collagen 1, that can antagonize the apoptosis of initially quiescent adult HSCs and, in combination with SF and interleukin-11, produce >15-fold net expansions of DSR-HSCs ex vivo within 7 days. These findings suggest a new molecular basis for HSC control and expansion.
Distinct stromal cell factor combinations can separately control hematopoietic stem cell survival, proliferation, and self-renewal.
Specimen part
View Samples