The mitochondrial matrix is unique in that it must integrate folding and assembly of proteins derived from nuclear and mitochondrial genomes. In C. elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial matrix-localized ornithine trans-carbamylase (OTC) induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here, we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response involved widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing due to transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3. This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt. Overall design: triplicate experiment of 2 conditions (untreated, GTPP treatment)
Mitochondrial unfolded protein response controls matrix pre-RNA processing and translation.
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View SamplesThe zebrafish heart remarkably regenerates after a severe ventricular damage followed by inflammation, fibrotic tissue deposition and removal concomitant with cardiac muscle replacement. We have investigated the role of the endocardium in this regeneration process. 3D-whole mount imaging in injured hearts revealed that GFP-labelled endocardial cells in ET33mi-60A transgenic fish become rapidly activated and highly proliferative at 3 days post cryoinjury (dpci). Endocardial cells extensively expand within the injury site and organize to form a coherent structure at 9 dpci that persists throughout the regeneration process. Upon injury, endocardial cells strongly up-regulate the Notch pathway ligand delta like4 (dll4) and the Notch receptors notch1b, notch2 and notch3. Expression profiling showed that Notch signalling inhibition affects endocardial gene expression and genes related to extracellular matrix remodelling and inflammation. Gain- and loss-of-function experiments revealed that Notch is required for the organization of the endocardium, attenuation of the inflammatory response and cardiomyocyte proliferation. These results demonstrate a novel structural and signalling role for the endocardium during heart regeneration. Overall design: RNA was extracted from apical tip of heart ventricles 72h after cryoinjured adult zebrafish heart treated with DMSO (Controls) or RO gamma secretase inhibitor at 24 and 48h post injury.
Notch signalling restricts inflammation and <i>serpine1</i> expression in the dynamic endocardium of the regenerating zebrafish heart.
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View SamplesWe use the Tlr2 mutant of zebrafish embryos model to study the transcriptome response to Mycobacterium marinum infection. We injected M.marinum into the caudal vein at 28 hours post fertilization and took samples at 4 days post infection. Overall design: This deep sequence study was designed to determine the gene expression profile in the Tlr2 mutant and heterozygote by M.marinum infection. RNA was isolated at 4 days post infection. Tlr2 mutants and heterozygotes zebrafish embryos were micro-injected into the caudal vein with 150CFU M.marinum, or PBS as a control at 28 hours post fertilization. After injections embryso were transerred into fresh egg water and incubated at 28 degree. At 4 days post infection triplicateds of 10 embryos per condition were snapfrozen in liquid nitogen, and total RNA was isolated using TRIZOL reagent.
Infection and RNA-seq analysis of a zebrafish tlr2 mutant shows a broad function of this toll-like receptor in transcriptional and metabolic control and defense to Mycobacterium marinum infection.
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View SamplesTo characterize LICs in ALL irrespective of surface markers expression, we investigated leukemia initiating activities of cellular subfractions of patient-derived xenograft BCP-ALL cells sorted according to different cell cycle phases (i.e. G0/G1 and G2/M) followed by transplantation onto NOD/SCID mice. All cell fractions led to leukemia engraftment indicating LIC activity irrespective of cell cycle stage. Most importantly, cells isolated from G0/G1 cell cycle phases led to early leukemia engraftment in contrast to cells from late cell cycle (G2/M). To further characterize cells with different engraftment potential in vivo, we analyzed the gene expression profiles of early (G1b early) and late (G2/M) engrafting cells.
Leukemia reconstitution <i>in vivo</i> is driven by cells in early cell cycle and low metabolic state.
Specimen part
View SamplesCNS leukemia is still the major obstacle in treating childhood acute lymphoblastic leukemia (ALL). We have used our NOD/SCID/huALL xenotransplantation model to identify molecular pathways leading to the infiltration of leukemic cells into the CNS compartment.
Central nervous system involvement in acute lymphoblastic leukemia is mediated by vascular endothelial growth factor.
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View SamplesThe anaerobic metabolism of the opportunistic pathogen Pseudomonas aeruginosa is important for growth and survival during persistent infections. The two Fnr-type transcription factors Anr and Dnr regulate different parts of the underlying network. Both are proposed to bind to a non-distinguishable DNA sequence named Anr box.
Anaerobic adaptation in Pseudomonas aeruginosa: definition of the Anr and Dnr regulons.
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View SamplesThe hemibiotrophic fungal pathogen Colletotrichum graminicola is the causal agent of anthracnose disease on maize stalks and leaves. After the formation of appressoria the host cell wall is penetrated by the conversion of appressorial turgor pressure into forceful ejection of a penetration peg. Subsequently, C. graminicola establishes biotrophic hyphae in the penetrated epidermis cell at around 36 hours post inoculation (hpi) until a switch of hyphal morphology and lifestyle takes place during the colonization of neighboring host cells at around 72 hpi. During the ensuing necrotrophic growth, dark necrotic lesions are formed that are visible as anthracnose symptoms. We used microarrays to detail the global programme of gene expression during the infection process of Colletotrichum graminicola in its host plant to get insight into the defense response of this compatible interaction and into the metabolic reprogramming needed to supply the fungus with nutrients.
Common Motifs in the Response of Cereal Primary Metabolism to Fungal Pathogens are not Based on Similar Transcriptional Reprogramming.
Time
View SamplesMonocyte chemoattractant protein 1 (MCP-1/CCL2) is critically involved in directing the migration of blood monocytes to sites of inflammation. Consequently, excessive MCP-1 secretion has been linked to many (auto)inflammatory diseases, whereas a lack of expression severely impairs immune responsiveness. We demonstrate that the atypical inhibitor of NF-B (IB), a transcriptional co-activator required for the selective expression of a subset of NF-B target genes, is a key activator of the Ccl2 gene. IB-deficient macrophages exhibited impaired secretion of MCP-1 when challenged with diverse inflammatory stimuli, such as lipopolysaccharide or peptidoglycan. These findings were reflected at the level of Ccl2 gene expression, which was tightly coupled to the presence of IB. Moreover, mechanistic insights acquired by chromatin immunoprecipitation demonstrate that IB is directly recruited to the proximal promoter region of the Ccl2 gene and required for histone H3K9 trimethylation. Finally, IB-deficient mice showed significantly impaired MCP-1 secretion and monocyte infiltration in an experimental model of peritonitis. Together, these findings suggest a distinguished role of IB in mediating the targeted recruitment of monocytes in response to local inflammatory events.
IκBζ is a transcriptional key regulator of CCL2/MCP-1.
Sex, Specimen part
View SamplesOur mouse model of BE in which overexpression of IL-1b in the squamous esophagus induces chronic inflammation leads to metaplasia and dysplasia at the squamo-columnar junction (SCJ) in the mouse gastro-esophageal junction resembles the human disease. Adult L2-IL1b mice were employed to investigate changes to the transcriptional landscape at the SCJ during disease progression from BE to EAC following pharmaceutical or genetic perturbations of interest to BE biology.
Notch Signaling Mediates Differentiation in Barrett's Esophagus and Promotes Progression to Adenocarcinoma.
No sample metadata fields
View SamplesEffects of loss-of-function of AtMIKC* MADS-box genes on the mature Arabidopsis pollen transcriptome.
MADS-complexes regulate transcriptome dynamics during pollen maturation.
Age, Specimen part
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