Project description:This model was used to study the relationship between NF-kB and PCD regulation and generated mice with combined conditional ablation of Traf2 and Caspase-8 (TRAF2/Casp-8LPC-KO) in order to block apoptosis and specifically study the role of necroptosis in Traf2-deficient hepatocytes in vivo.
Project description:Alternative splicing (AS) increases the informational content of the genome and is more prevalent in the brain than in any other tissue. The splicing factor Tra2b (Sfrs10) can modulate splicing inclusion of exons by specifically detecting GAA-rich binding motifs and its absence causes early embryonic lethality in mice. TRA2B has been shown to be involved in splicing processes of Nasp (nuclear autoantigenic sperm protein), MAPT (microtubule associated protein tau) and SMN (survival motor neuron), and is therefore implicated in spermatogenesis and neurological diseases like AlzheimerM-^Rs disease, dementia, ParkinsonM-^Rs disease and spinal muscular atrophy. Here we generated a neuronal-specific Tra2b knock-out mouse that lacks Tra2b expression in neuronal and glial precursor cells by using the Nestin-Cre. Neuronal-specific Tra2b knock-out mice die immediately after birth and show severe abnormalities in cortical development, which are caused by massive apoptotic events in the ventricular layers of the cortex, demonstrating a pivotal role of Tra2b for the developing central nervous system. Using whole brain RNA on exon arrays we identified differentially expressed alternative exons of Tubulin?1 and Shugoshin like2 as in vivo targets of Tra2b. Most interestingly, we found increased expression of the cyclin dependent kinase inhibitor 1a (p21) which we could functionally link to neuronal precursor cells in the affected brain regions. We provide further evidence that the absence of Tra2b causes p21 upregulation and ultimately cell death in NSC34 neuronal-like cells. These findings demonstrate that Tra2b regulates splicing events essential for maintaining neuronal viability during development. Apoptotic events triggered via p21 might not be restricted to the developing brain but could possibly be generalized to the whole organism and explain early embryonic lethality in Tra2b-depleted mice.
Project description:Tbx20 is a transcription factor known to play important roles in embryonic and adult mouse heart function. Our goal in this work was to better understand the function of this gene in embryonic (E11.5) mouse cardiomyocytes that form the developing chambers, expanding our knowledge of its role in heart development. To elucidate the role of Tbx20 in mouse cardiomyocytes, we generated conditional Tbx20 knockout and compared 4 samples with 4 samples of wild-type cardiomyocytes. We found evidence of regulation of cell cycle genes by Tbx20, which are involved in proliferation. In addition, Tbx20 seems to bind and regulate an enhancer of CoupTFII in the atrium, a gene involved in atrial development.
Project description:Using a high-end mass spectrometry, we screened phosphoproteins and phosphopeptides in five types of Alzheimer's disease (AD) mouse models (5xFAD, APP-tg, PS1-tg, PS2-tg and APP-KI) and four types of frontotemporal lobar degeneration (FTLD) mouse models(CHMP2B-KI, PGRN-KI, VCP-KI and TDP43-KI) at multiple time points (1, 3 and 6 months).
Project description:Gpr88 is an orphan G protein-coupled receptor highly expressed in the striatum, a region important for motor control and learning. We developed a mouse lacking this receptor (genotype Gpr88Cre/Cre) by replacing most of the open-reading-frame of the Gpr88 gene with Cre recombinase. When comparing the homozygous knockouts against wild-type mice (Gpr88+/+), we have observed that knockout mice are hyperactive, present motor deficits and impaired cue-based learning. However, the signaling pathways downstream of Gpr88 are unknown. To identify putative downstream factors we designed a microarray experiment to identify gene expression changes in the striata of animals lacking Gpr88.
Project description:Triggering of B cell receptors (BCR) induces a massive synthesis of NFATc1 in splenic B cells. By inactivating the Nfatc1 gene and re-expressing NFATc1 we show that NFATc1 levels are critical for the survival of splenic B cells upon BCR stimulation. NFATc1 ablation led to decreased BCR-induced Ca++ flux and proliferation of splenic B cells, increased apoptosis and suppressed germinal centre formation and immunoglobulin class switch by T cell-independent antigens. By controlling IL-10 synthesis in B cells, NFATc1 supported the proliferation and IL-2 synthesis of T cells in vitro and appeared to contribute to the mild clinical course of Experimental Autoimmune Encephalomyelitis in mice bearing NFATc1-/- B cells. These data indicate NFATc1 as a key factor controlling B cell function. Splenic mice cells were isolated from mice bearing NFATc1 deficient B-cells and from control mice, stimulated with anti-IgM for 0h, 3h, 8h and 16h, respectively and isolated using Milteny beads to enrich the B cell population. This experiment was performed in 3 biological replicates.
Project description:Epigenetic factors have been implicated in the regulation of CD4(+) T-cell differentiation. Jmjd3 plays a role in many biological processes, but its in vivo function in T-cell differentiation remains unknown. Here we report that Jmjd3 ablation promotes CD4(+) T-cell differentiation into Th2 and Th17 cells in the small intestine and colon, and inhibits T-cell differentiation into Th1 cells under different cytokine-polarizing conditions and in a Th1-dependent colitis model. Jmjd3 deficiency also restrains the plasticity of the conversion of Th2, Th17 or Treg cells to Th1 cells. The skewing of T-cell differentiation is concomitant with changes in the expression of key transcription factors and cytokines. H3K27me3 and H3K4me3 levels in Jmjd3-deficient cells are correlated with altered gene expression through interactions with specific transcription factors. Our results identify Jmjd3 as an epigenetic factor in T-cell differentiation via changes in histone methylation and target gene expression. ChIP-seq of histone modification marks H3K4me3 and H3K27me3 in WT and JMJD3 cKO mouse CD4+ T-cells
Project description:Correct neural progenitor fate determination requires the coordination of extrinsic fate determinant signals with intrinsic responses. Post-translational modifications dynamically alter protein function and so are ideally situated to regulate development. Here we show that the deubiquitylaying enzyme, Usp9x modulates both intrinsic and extrinsic regulators of mouse neural progenitors. Nestin-cre mediated deletion of Usp9x from neural progenitors results in a transient disruption of cell adhesion and apical-basal polarity as well as the premature differentiation of intermediate neural progenitors. Ablation of Usp9x also significantly increased β-catenin protein levels, especially S33/S37/T41 phospho-β-catenin, and Wnt signalling. Usp9x was found to be part of the β-catenin destruction complex and loss of Usp9x affects destruction complex composition. Notch signalling was also increased in Usp9x ablated neural progenitors, coinciding with decreased Itch and Numb, and increased Notch intracellular domain protein levels. Usp9x co-localized and immunopreciptiated with Numb from neural progenitors suggesting it is required for Numb stabilisation. These data suggest Usp9x plays a role in coordinating intrinsic responses to extrinsic signals during neural development.
Project description:Approximately 60-70% of patients with 22q11.2 deletion syndrome (22q11.2DS; velo-cardio-facial syndrome/DiGeorge syndrome) have cardiac outflow tract anomalies including persistent truncus arteriosus (PTA) as the most severe defect. Among the genes in the 22q11.2 region, TBX1, encoding a T-box transcription factor is a major candidate for cardiovascular malformations and its inactivation in mice results in a PTA. To identify novel signaling mechanisms that function downstream, we found that Tbx1 restricts canonical Wnt signaling in the pharyngeal apparatus. To test for tissue specificity within the pharyngeal apparatus, we inactivated Tbx1 in the anterior portion of the secondary heart field (AHF) mesoderm using the Mef2c-AHF-Cre allele and observed a full penetrant PTA (n = 30). Tbx1 promotes progenitor cells but restricts differentiation whereas Wnt signaling, in the AHF, promotes cardiomyocyte differentiation. To determine whether Tbx1 and canonical Wnt signaling act in opposing pathways, both alleles of Tbx1 and one β-catenin allele were inactivated in the AHF and 85% of them (n = 35) showed partial or complete rescue. The antagonistic function of the two pathways was further confirmed by gene expression profiling, indicating that these two pathways provide a key balance in the AHF to prevent premature differentiation of progenitor cells prior to reaching the cardiac outflow tract. We inactivatedTbx1 and beta-catenin allele to identify function of Tbx1 and beta-catenin in the anterior portion of the secondary heart field (AHF) mesoderm. We also inactivated both alleles of Tbx1 and one β-catenin alleles (rescue design) to determine whether Tbx1 and canonical Wnt signaling act in opposing pathways
Project description:Excessive glucose production in the liver is a key factor in the hyperglycemia observed in diabetes mellitus type 2. It is generally agreed to result from an increase in hepatic gluconeogenesis. Considerable attention has been devoted to the transcriptional regulation of key gluconeogenic enzymes, but much less is known about the regulation of amino-acid catabolism, which generates gluconeogenic substrates. Here, we highlight a novel role of LKB1 in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have higher levels of hepatic amino acid catabolism, driving gluconeogenesis. This effect was observed during both fasting and the postprandial period, identifying Lkb1 as a critical suppressor of postprandial hepatic gluconeogenesis. Hepatic Lkb1 deletion was associated with major changes in whole-body metabolism, leading to a lower lean body mass and, in the longer term, sarcopenia and cachexia, as a consequence of the diversion of amino acids to liver metabolism at the expense of muscle. Using genetic and pharmacological approaches, we identified the aminotransferases and specifically, Agxt as effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis. The present dataset is from the phosphoproteomic analysis of the refed mice in a study where a global quantitative analysis ( PXD013478 ) is also described in the same publication.