The transition of skotomorphogenesis to photomorphogenesis is induced by the perception of light and is characterized by the inhibition of hypocotyl elongation and opening of cotyledons. Although it is known that the plant hormone cytokinin, when applied in high concentrations, inhibits hypocotyl elongation in the dark-grown Arabidopsis plants, it is unclear to what extent this response is the result of cytokinin alone or cytokinin-induced ethylene production. We show that treatment of etiolated seedlings in presence of ethylene inhibitors (eg. AgNO3) or treatment of the ethylene-resistant mutant ein2, resulted in a significant inhibition of hypocotyl elongation. This indicates that cytokinin induced de-etiolation is largely independent of ethylene and suggests a close connection between the cytokinin two component system and the light singalling networks. We show that this cytokinin signal is mainly mediated through the cytokinin receptor ARIBIDOPSIS HISTIDIN KINASE 3 (AHK3) and the ARABIDOPSIS RESPONSE REGULATORS 1 (ARR1) in combination with ARR12. Interestingly, mutation of COP1, DET1 and CIN4/COP10 renders plants insensitive to cytokinin and these factors are indispensable for the transcriptional response during cytokinin induced de-etiolation which indicates that a functional light signaling pathway is essential for this cytokinin response. In addition, the cytokinin effect on hypocotyl elongation is highly dependent on the ambient light conditions where higher light intensities causes a switch in the response to CK from an inhibitor to a promoter of hypocotyl elongation. Overall design: Investigation of the effect of 3 µM BA in presence of 10 µM AgNO3 on hypocotyl elongation in 4-days-old etiolated Arabidopsis seedlings, in triplicate, using RNA-seq analysis
Ethylene-independent promotion of photomorphogenesis in the dark by cytokinin requires COP1 and the CDD complex.
Age, Specimen part, Treatment, Subject
View SamplesArabipdosis thaliana (ecotype Col-0) was infected with the root pathogen Plasmodiophora brassicae. Gene expression of the host plant has been analyzed at two time points after inoculation (10 and 23 days after inoculation) compared to the correspondend control plants.
Transcriptome analysis of Arabidopsis clubroots indicate a key role for cytokinins in disease development.
Age, Specimen part, Cell line, Time
View SamplesWe expressed a constitutively active mutant of MEK5 (MEK5D) in human primary endothelial cells (EC) to study the transcriptional and functional responses to Erk5 activation under static conditions.
Erk5 activation elicits a vasoprotective endothelial phenotype via induction of Kruppel-like factor 4 (KLF4).
Cell line
View SamplesInflammation has a causal role in many cancers. In prostate cancers, epidemiological data suggest a link between prostatitis and subsequent cancer development, but a proof for this concept in a tumor model has been lacking. A constitutively active version of the IkappaB kinase 2 (IKK2), the molecule activated by a plethora of inflammatory stimuli, was expressed specifically in the prostate epithelium. Signaling of the IKK2/NF-kappaB axis was insufficient for transformation of prostate tissue. However, while PTEN+/- epithelia exhibited intraepithelial neoplasias only recognizable by nuclear alterations, additional IKK2 activation led to an increase in tumor size and formation of cribriform structures and to a fiber increase in the fibroblastic stroma. This phenotype was coupled with inflammation in the prostate gland characterized by infiltration of granulocytes and macrophages. Molecular characterization of the tissues showed a specific loss of smooth muscle markers as well as expression of chemokines attracting immune cells. Isolation of epithelial and stromal cells showed differential chemokine expression by these cells. Correlation studies showed the inflammatory phenotype coupled to loss of smooth muscle in infiltrated glands, but maintenance of the phenotype in glands where inflammation had decreased. Despite the loss of the smooth muscle barrier, tumors were not invasive in a stable genetic background. Data mining revealed that smooth muscle markers are downregulated in human prostate cancers and literature data show that loss of these markers in primary tumors is associated with subsequent metastasis. Our data show that loss of smooth muscle and invasiveness of the tumor are not coupled. Thus, inflammation during early steps of tumorigenesis can lead to increased tumor size and a potential change in the subsequent metastatic potential, but the tumor requires an additional transformation to become a carcinoma.
Persistent inflammation leads to proliferative neoplasia and loss of smooth muscle cells in a prostate tumor model.
Age, Specimen part
View SamplesThe protease activity of the paracaspase MALT1 plays an important role in antigen receptor-mediated lymphocyte activation by controlling the activity of the transcription factor NF-kB and is thus essential for the expression of inflammatory target genes.
MALT1 Protease Activity Controls the Expression of Inflammatory Genes in Keratinocytes upon Zymosan Stimulation.
Treatment
View SamplesDiffuse large B-cell lymphoma (DLBCL) represents the most common form of lymphoma. We could show that in DLBCL cell lines the transcription factor NFAT is constitutively activated and drives the survival of a DLBCL subset. Aim of the analysis was to identify NFAT target genes in a NFAT-dependent (HBL-1) or -independent (HT) DLBCL cell line. To block NFAT activity, the DLBCL cells were treated with the calcineurin inhibitor cyclosporin A (CsA) up to 48 h. With this approach, we identified several survival-related NFAT target genes in HBL-1 cells that might explain the toxic effects of calcineurin inhibitors.
Targeting chronic NFAT activation with calcineurin inhibitors in diffuse large B-cell lymphoma.
Treatment
View SamplesWe used microarrays to detail the global gene expression changes following apical infection of porcine choroid plexus epithelial cells (PCPEC) with Streptococcus suis (S. suis)
In vitro transcriptome analysis of porcine choroid plexus epithelial cells in response to Streptococcus suis: release of pro-inflammatory cytokines and chemokines.
Specimen part
View SamplesThe objective of this study was to compare the transcriptional repertoire of mature human neutrophils before and after GM-CSF treatment by using oligonucleotide microarrays.
RhoH/TTF negatively regulates leukotriene production in neutrophils.
Specimen part
View SamplesDuring development, thymocytes bearing a moderately self-reactive T cell receptor (TCR) can be selected to become regulatory T (Treg) cells. Several observations suggest that also in the periphery mature Treg cells continuously receive self-reactive TCR signals. However, the importance of this inherent autoreactivity for Treg cell biology remains poorly defined.
Continuous T cell receptor signals maintain a functional regulatory T cell pool.
Specimen part
View SamplesAlveolar epithelial type II (ATII)-like cells can be generated from murine embryonic stem cells (ESCs), although to date, no robust protocols applying specific differentiation factors are established. We hypothesized that the keratinocyte growth factor (KGF), an important mediator of lung organogenesis and primary ATII cell maturation and proliferation, together with dexamethasone, 8-bromoadenosine-cAMP, and isobutylmethylxanthine (DCI), which induce maturation of primary fetal ATII cells, also support the alveolar differentiation of murine ESCs. Here we demonstrate that the above stimuli synergistically potentiate the alveolar differentiation of ESCs as indicated by increased expression of the surfactant proteins (SP-) C and SP-B. This effect is most profound if KGF is supplied not only in the late stage, but at least also during the intermediate stage of differentiation. Our results indicate that KGF most likely does not enhance the generation of (mes)endodermal or NK2 homeobox 1 (Nkx2.1) expressing progenitor cells but rather, supported by DCI, accelerates further differentiation/maturation of respiratory progeny in the intermediate phase and maturation/proliferation of emerging ATII cells in the late stage of differentiation. Ultrastructural analyses confirmed the presence of ATII-like cells with intracellular composite and lamellar bodies. Finally, induced pluripotent stem cells (iPSCs) were generated from transgenic mice with ATII cell-specific lacZ reporter expression. Again, KGF and DCI synergistically increased SP-C and SP-B expression in iPSC cultures, and lacZ expressing ATII-like cells developed. In conclusion, ATII cell-specific reporter expression enabled the first reliable proof for the generation of murine iPSC-derived ATII cells. In addition, we have shown KGF and DCI to synergistically support the generation of ATII-like cells from ESCs and iPSCs. Combined application of these factors will facilitate more efficient generation of stem cell-derived ATII cells for future basic research and potential therapeutic application.
Keratinocyte growth factor and dexamethasone plus elevated cAMP levels synergistically support pluripotent stem cell differentiation into alveolar epithelial type II cells.
Specimen part, Treatment
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