The lack of mouse models permitting the specific ablation of tissue-resident macrophages and monocyte-derived cells complicates understanding of their contribution to tissue integrity and to immune responses. Here we use a new model permitting diphtheria-toxin (DT)-mediated depletion of those cells and in which dendritic cells are spared. We showed that the myeloid cells of the mouse ear skin dermis are dominated by a population of melanin-laden macrophages, called melanophages, that has been missed in most previous studies. By using gene expression profiling, DT-mediated ablation and parabiosis, we determined their identity including their similarity to other skin macrophages, their origin and their dynamics. Limited information exist on the identity of the skin cells responsible for long-term tattoo persistence. Benefiting of our knowledge on melanophages, we showed that they are responsible for retaining tattoo pigment particles through a dynamic process which characterization has direct implications for improving strategies aiming at removing tattoos.
Unveiling skin macrophage dynamics explains both tattoo persistence and strenuous removal.
Specimen part, Treatment
View SamplesPsoriasis 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 SamplesNumerous CD11b+ myeloid cells are present within the dermis. They are very heterogeneous and can be divided in dermal DCs, tissue monocytes and tissue macrophages. At steady state, only CD11b+ DC migrate from the dermis to the skin draining lymph nodes whereas upon DNFB-induced inflammation, CD11b+ DC as well as dermal monocytes migrated to the lymph nodes. The objective of this study was to use gene expression profiling to rigorously identify the different subsets of dermal CD11b+ myeloid cells at steady state and upon inflammation and to characterize their functional potential.
Origins and functional specialization of macrophages and of conventional and monocyte-derived dendritic cells in mouse skin.
Sex, Age, Specimen part
View SamplesEvaluate the change in transcription factors that have a role in human mesenchymal stem cell (hMSC) commitment to a cardiomyocyte lineage when co-cultured for 4 days with rat neonatal cardiomyocytes and before acquiring a recognizable cardiac phenotype.
Calcium dependent CAMTA1 in adult stem cell commitment to a myocardial lineage.
Specimen part, Disease
View SamplesDetermine the effect of miR-203 expression on the global mRNA expression in mesenchymal breast cancer cell line.
Epigenetic silencing of microRNA-203 is required for EMT and cancer stem cell properties.
Specimen part, Cell line, Treatment
View SamplesIn order to identify the effects of Tcfeb overexpression on the kidney transcriptome, we performed Affymetrix Gene-Chip hybridization experiments for the double heterozygous KSP_CRE/KSP_Tcfeb 14 days old mice as compared to control KSP_CRE mice
Modelling TFE renal cell carcinoma in mice reveals a critical role of WNT signaling.
Specimen part
View SamplesIn order to identify the effects of Tcfeb overexpression on the kidney transcriptome, we performed Affymetrix Gene-Chip hybridization experiments for the double heterozygous KSP_CRE/KSP_Tcfeb mice as compared to control KSP_CRE mice
Modelling TFE renal cell carcinoma in mice reveals a critical role of WNT signaling.
Specimen part
View SamplesGlobal gene expression analysis of grapevine cv. Pinot Noir berries during development and ripening. Time-course comparison of samples collected at three developmental stages (stages 33, 34 and 36 according to the modified E-L system, ref: Coombe BG, Aust J Grape Wine Res 1995, 1: 104-110) during three seasons (2003, 2005 and 2006).
Genome-wide transcriptional analysis of grapevine berry ripening reveals a set of genes similarly modulated during three seasons and the occurrence of an oxidative burst at vèraison.
Age, Specimen part, Time
View SamplesGlobal gene expression analysis of grapevine cv. Pinot Noir berries during development and ripening. Time-course comparison of samples collected at three developmental stages (stages 33, 34 and 36 according to the modified E-L system, ref: Coombe BG, Aust J Grape Wine Res 1995, 1: 104-110) during three seasons (2003, 2005 and 2006). Data for each of the three seasons were normalized independently within each season, using gcRMA.
Genome-wide transcriptional analysis of grapevine berry ripening reveals a set of genes similarly modulated during three seasons and the occurrence of an oxidative burst at vèraison.
Specimen part
View SamplesThe proper accumulation of BBX22 mediated by COP1 is crucial for plants to maintain better growth fitness when growing in the dark environment as well as responding to seasonal changes in day-length. The constitutive-photomorphogenic development of the cop1 mutant is enhanced in cop1BBX22-GFPox plants, which show a short hypocotyl, high anthocyanin accumulation and expression of light-responsive genes. Target genes responsible for the exaggerated light phenotype in cop1BBX22-GFPox plants were revealed by comparing transcriptomes among dark-grown wild-type, cop1 and cop1BBX22-GFPox plants. Expression of genes regulated by light and multiple hormones are altered in plants over-accumulating BBX22, implying a coordination role of BBX22 in light- and hormone-mediated seedling development.
COP1-mediated degradation of BBX22/LZF1 optimizes seedling development in Arabidopsis.
Age, Specimen part
View Samples