Astrocytes, the most prominent glial cell type in the brain, send specialized processes called endfeet around blood vessels and express a large molecular repertoire regulating the cerebrovascular system physiology. One of the most striking properties of astrocyte endfeet is their enrichment in gap junction protein Connexin 43 and 30 (Cx43 and Cx30) allowing in particular for direct intercellular trafficking of ions and small signaling molecules through perivascular astroglial networks. In this study, we addressed the specific role of Cx30 at the gliovascular interface. Using an inactivation mouse model for Cx30 (Cx30?/?), we showed that absence of Cx30 does not affect blood-brain barrier (BBB) organization and permeability. However, it results in the cerebrovascular fraction, in a strong upregulation of Sgcg encoding g-Sarcoglycan (SG), a member of the Dystrophin-associated protein complex (DAPC) connecting cytoskeleton and the extracellular matrix. The same molecular event occurs in Cx30T5M/T5M mutated mice, where Cx30 channels are closed, demonstrating that Sgcg regulation relied on Cx30 channel functions. We further characterized the cerebrovascular Sarcoglycan complex (SGC) and showed the presence of a-, ß-, d-, ?-, e- and ?- SG, as well as Sarcospan. Altogether, our results suggest that the Sarcoglycan complex is present in the cerebrovascular system, and that expression of one of its members, g-Sarcoglycan, depends on Cx30 channels. As described in skeletal muscles, the SGC may contribute to membrane stabilization and signal transduction in the cerebrovascular system, which may therefore be regulated by Cx30 channel-mediated functions. Overall design: Comparison of 3-month-old Cx30 deleted mice against WT genetic background.
The Sarcoglycan complex is expressed in the cerebrovascular system and is specifically regulated by astroglial Cx30 channels.
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View SamplesEffect of the ablation of connexin 30 in the stria vascularis
Connexin30 deficiency causes instrastrial fluid-blood barrier disruption within the cochlear stria vascularis.
Age, Specimen part, Disease, Time
View SamplesWnt signaling in early eye development, specifically the lens placode shows expression of 12 out of 19 Wnt ligands. We these Wnt activities were suppressed using conditional deletion of Wntless, dramatic phenotypic changes in morphogensis occurred.
Wnt ligands from the embryonic surface ectoderm regulate 'bimetallic strip' optic cup morphogenesis in mouse.
Specimen part
View SamplesHere, using genome wide analysis, we demonstrate that canonical mRNA is processed post-transcriptionally through an alternative cleavage and polyadenylation mechanism. As a result of this process, the downstream cleavage fragment of the 3'UTR remains uncapped and stable This finding indicates that different parts of gene mRNA are separate and independent, by re-annotating the human transcriptome using this model, we provide a new overview of the function and impact of microRNA (miRNA) Our results shed new light on the mammalian transcriptome and show that what were considered as 3'UTRs are in fact autonomous RNA fragments. Overall design: Examination of mRNA levels and cleavage across transcripts in U2OS and 293 cell types (3 replicates each)
Post-transcriptional 3´-UTR cleavage of mRNA transcripts generates thousands of stable uncapped autonomous RNA fragments.
Treatment, Subject
View SamplesThe identification of subtype-specific translocations has revolutionized diagnostics of sarcoma and provided new insight into oncogenesis. We used RNA-Seq to investigate samples diagnosed as small round cell tumors of bone, possibly Ewing sarcoma, but lacking the canonical EWSR1-ETS translocation. A new fusion was observed between the BCL6 co-repressor (BCOR) and the testis specific cyclin B3 (CCNB3) genes on chromosome X. RNA-Seq results were confirmed by RT-PCR and cloning the tumor-specific genomic translocation breakpoints. 24 BCOR-CCNB3-positive tumors were identified among a series of 594 sarcomas. Gene profiling experiments indicate that BCOR-CCNB3-positive cases are biologically distinct from other sarcomas, particularly Ewings sarcoma. Finally, we show that CCNB3 immunohistochemistry is a powerful diagnostic marker for this group of sarcoma and that over-expression of BCOR-CCNB3 or of a truncated CCNB3 activates S-phase in NIH3T3 cells. Thus the intrachromosomal X fusion described here represents a new subtype of bone sarcoma caused by a novel gene fusion mechanism.
A new subtype of bone sarcoma defined by BCOR-CCNB3 gene fusion.
Sex, Age, Specimen part
View SamplesGene expression in glioblastoma cells from patients before treatment. The cells were inhibited or not for FGFR1.
FGFR1/FOXM1 pathway: a key regulator of glioblastoma stem cells radioresistance and a prognosis biomarker.
Specimen part
View SamplesGlioblastomas (GBM) are brain tumors which display a bad prognosis despite conventional treatment associating surgical resection and subsequent radio-chemotherapy. These tumors are defined by an abundant and abnormal vascularization as well as by an important cellular heterogeneity. GBM notably contain a subpopulation of GBM stem-like cells (GSC) which contribute to tumor aggressiveness, resistance, and recurrence. Moreover, GSC directly take part in the formation of new vessels via their transdifferentiation into tumor derived endothelial cells (TDEC). Considering the importance of the vascularization in the GBM, we postulate that radiation could enhance the transdifferentiation of GSC into TDEC. Here, we show that ionizing radiation potentiates endothelial features of TDEC obtained from 3 patient-derived primocultures of GSC. Indeed, TDEC obtained from irradiated GSC (TDEC IR+) migrate more towards VEGF, form more pseudotubes in Matrigel in vitro and develop more functional blood vessel in Matrigel plugs implanted in Nude mice than TDEC obtained from non-irradiated GSC. Transcriptomic analysis allows us to highlight an overexpression of Tie2 in TDEC IR+ which is associated with the activation of AKT signaling pathway. All radiation-induced effects on TDEC IR+ were abolished by using a Tie2 kinase inhibitor, confirming the role of Tie2 signaling pathway in this process. Finally, the number of Tie2+ vessels is increased in recurrent GBM compared with matched untreated tumors. In conclusion, we show that irradiation potentiates proangiogenic features of TDEC throught Tie2/AKT signaling pathway. New therapeutic stategies associating standard teatment and an inhibitor of Tie2 signaling pathway should be considered for forthcoming trials.
Ionizing radiation induces endothelial transdifferentiation of glioblastoma stem-like cells through the Tie2 signaling pathway.
Specimen part
View SamplesWe study the effect of four QTN in RME1, IME1 & RSF1 that are causative for variation in sporulation efficiency. We investigate the relationship between genotype, gene expression and phenotype and whether the amount of gene expression variation explained by the sporulation QTN is predictive of the amount of phenotypic variation explained by them. Overall design: RNA-Seq analysis of 4 replicates each of 16 allele replacement panel strains containing all combinations of the four sporulation QTN after 2 hours in sporulation medium.
Single nucleotide variants in transcription factors associate more tightly with phenotype than with gene expression.
Subject
View SamplesPurpose: We observed protein homeostasis modulations when anc-1 is knocked-down. We wanted to measure changes in gene expression profiles following this manipulation. Methods: We treated wild type (strain N2) or polyQ35-YFP (strain AM140) nematodes, which express toxic aggregative proteins that challenge their protein homeostasis, with anc-1 RNAi until day six of adulthood, and compared their gene expression levels to those of untreated worms. Results: The knockdown of anc-1 leads to modified expression levels of hundreds of genes. There is an enrichment of transcription factors and protein homeostasis modulators, such as E3 ubiquitin ligases. Conclusions: anc-1 regulates protection from toxic aggregative proteins, at least partially, by regulating the expression of genes that encode protein homeostasis factors. Overall design: Wild type strain, three repeats; polyQ35-YFP strain, four repeats. Each repeat has two conditions: untreated (EV), and RNAi toward anc-1.
Gene expression modulation by the linker of nucleoskeleton and cytoskeleton complex contributes to proteostasis.
Cell line, Subject
View SamplesVon Willebrand factor is a paracrine/autocrine regulator of human mesenchymal stem cell adhesion to distressed/apoptotic endothelial cells.
Von willebrand factor increases endothelial cell adhesiveness for human mesenchymal stem cells by activating p38 mitogen-activated protein kinase.
Specimen part
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