Project description:Analysis of gene expression changes in the von Hippel Lindau when mutant compared to wild-type at 4dpf using a whole genome microarray expression profiling. The von Hippel Lindau mutant displays a systemic hypoxic response under normoxic conditions. We performed single-colour microarrays to identify the gene expression changes which underpin the hypoxic phenotype. We used 3 biological replicates from both mutant and control, followed by analysis using Limma to identify significant gene expression changes. This work, together with ChIP-seq data for the Hif-1α in von Hippel Lindau mutants, should allow for the Hif-1α dependency of these gene expression changes to be assessed. The changes in gene expression between von Hippel Lindau mutants and wild-type controls was measured at 4 days post fertilisation. For both wild-type and mutant, 3 biological replicates, each of 30 embryos were used.
Project description:Analysis of the binding sites of Hif-1α in both wild-type and von Hippel Lindau mutant zebrafish lines at 4dpf by ChIP linked next generation sequencing. The von Hippel Lindau mutant displays a systemic hypoxic response under normoxic conditions. Results show the extent of Hif-1α binding to the genome, and provide a basis for analysis of the transcriptional response to genetically induced hypoxia in zebrafish. Analysis of the DNA binding sites of Hif-1α in both wild-type and von Hippel Lindau mutant zebrafish lines at 4dpf. The von Hippel Lindau mutant displays a systemic hypoxic response under normoxic conditions. Results show the extent of Hif-1α binding to the genome, and provide a basis for analysis of the dependency of the transcriptional response on Hif-1α in conditions of genetically induced hypoxia in zebrafish.
Project description:Pathogenic mycobacteria have the ability to survive within macrophages and persist inside granulomas composed of host immune cells. The complex host-pathogen interactions that determine the outcome of a mycobacterial infection process result in marked alterations of the host gene expression profile. Here we used the zebrafish model to investigate the specificity of the host response to infections with two mycobacterium strains that give distinct disease outcomes: an acute disease with early lethality or a chronic disease with granuloma formation, caused by Mycobacterium marinum strains Mma 20 and E11, respectively. We performed a microarray study of different stages of disease progression in adult zebrafish and found that the acute and the chronic strains evoked partially overlapping host transcriptome signatures, despite that they induce profoundly different disease phenotypes. Both strains affected many signaling cascades, including Wnt and Tlr pathways. Interestingly, the strongest differences were observed at the initial stage of the disease. The immediate response to the acute strain was characterized by higher expression of genes encoding MHC class I proteins, matrix metalloproteinases, transcription factors, cytokines and other common immune response proteins. In contrast, small GTPase and histone gene groups showed higher expression in response to the chronic strain. We also found that nearly 1,000 mycobacterium-responsive genes overlapped between the expression signatures of infected zebrafish adults and embryos at different stages of granuloma formation. Since adult zebrafish possess an adaptive immune system similar to mammals and zebrafish embryos rely solely on innate immunity, this overlap indicates a major contribution of the innate component of the immune system in the response to mycobacterium infection. Taken together, our comparison of the transcriptome responses involved in acute versus chronic infections and in the embryonic versus adult situation provides important new leads for investigating the mechanism of mycobacterial pathogenesis. Zebrafish were handled in compliance with the local animal welfare regulations and maintained according to standard protocols (http://ZFIN.org). Infection experiments were approved by the local animal welfare committee (DEC) of the VU University medical center and of Leiden Univeristy. Infection experiments with adult fish were performed on young males selected from a wild type laboratory-breeding colony and acclimated to their new environment for one week in a quarantine area. These fish were kept at 28ËC on a 12:12 h light/dark rhythm throughout the experiment. Groups of 30 fish, infected with the same dose and strain of mycobacteria, were kept in small fish tanks (10 l) with their own separate filtering system (Eheim Ecco). Zebrafish were inoculated intraperitoneally as previously described (Meijer et al., 2004) with approximately 10000 bacteria or with phosphate-buffered saline (PBS) as a control. For the acute infection study with E11 and Mma20 strains, 3 fish per group were sacrificed at 1 and 6 days post infection (dpi) and used for microarray analysis. For comparison with the end stage of chronic E11 infection we used RNA samples from our previously published chronic infection study (Meijer et al., 2005; control fish c2 and infected fish i2) and additional RNA samples (2 controls, 2 infected) from a similar infection experiment. All chronically infected fish showed overt signs of fish tuberculosis, including lethargy and skin ulcers. Histological examination of fish from the same experiments confirmed that the pathology of infected fish corresponded to fish tuberculosis (Van der Sar et al., 2004) and that no characteristics of the disease were present in the control fish. Infection experiments at the embryonic stage were performed using mixed egg clutches from different pairs of AB strain zebrafish. Embryos were grown at 28,5 -30 °C in egg water (60µg/ml Instant Ocean see salts) and for the duration of bacterial injections embryos were kept under anaesthesia in egg water containing 0.02% buffered 3-aminobenzoic acid ethyl ester (tricaine, Sigma). Embryos were staged at 28 hours post fertilization (hpf) by morphological critera (Kimmel et al.) and approximately 50 cfu of E11 bacteria were injected into the caudal vein close to the urogenital opening. As a control an equal volume of PBS was likewise injected. Infection experiments were carried out in triplicate on separate days and pools of 15-20 embryos were taken at 2, 24 and 120 hours post infection (hpi).
Project description:Patient-derived bone tumor (osteosarcoma and giant cell tumor of bone) cells, and the normal mesenchymal stem cells and osteoblasts were cultured and subjected to UV crosslinking (UV) at 254 nm or without crosslinking (noUV) as negative controls. Subsequently, RNA-binding proteins (RBPs) were identified by eRIC.
Project description:Spatial tissue proteomics integrating whole-slide imaging, laser microdissection and ultrasensitive mass spectrometry is a powerful approach to link cellular phenotypes to functional proteome states in (patho)physiology. To be applicable to large patient cohorts and low sample input amounts, including single-cell applications, loss-minimized and streamlined end-to-end workflows are key. We here introduce an automated sample preparation protocol for laser microdissected samples utilizing the cellenONE® robotic system, which has the capacity to process 192 samples in three hours. Following laser microdissection collection directly into the proteoCHIP LF 48 or EVO 96 chip, our optimized protocol facilitates lysis, formalin de-crosslinking and tryptic digest of low-input archival tissue samples. The seamless integration with the Evosep ONE LC system by centrifugation allows ‘on-the-fly’ sample clean-up, particularly pertinent for laser microdissected workflows. We validate our method in human tonsil archival tissue, where we profile proteomes of spatially-defined B-cell, T-cell and epithelial microregions of 4,000 µm2 to a depth of ~2,000 proteins and with high cell type specificity. We finally provide detailed equipment templates and experimental guidelines for broad accessibility.
Project description:Despite significant progress in the mechanistic understanding of epigenetic reprogramming of cells, the basis of 'organ reprogramming' by (epi-)gene-environment interactions remained largely obscured. Here, we use the ether-induced haltere-to-wing transformations in Drosophila as a model for epigenetic “reprogramming� at the whole organism level. Our findings support a mechanistic chain of events explaining why and how brief embryonic exposure to ether leads to organ transformation manifested at the larval stage and on. We show that ether interferes with protein integrity in the egg leading to altered deployment of Hsp90 and widespread repression of Trithorax-mediated establishment of H3K4 tri-methylations throughout the genome. Despite this global suppression of H3K4me3, Ubx targets, and wing development genes preferentially retain higher levels of active chromatin marks. This preferential retention pre-disposes Ubx targets and wing genes for later up-regulation in the larval haltere disc, hence the wing-like outcome. Consistent with compromised protein integrity during the exposure, the penetrance of bithorax transformation increases by genetic or chemical reduction of Hsp90 function. Moreover, joint reduction in Hsp90 and trx gene dosage can cause bithorax transformations even without exposure to ether, supporting underlying epistasis between Hsp90 and trx loss-of-functions. These findings implicate environmental disruption of protein integrity at the onset of histone methylations with a modification of epigenetic memory. The emerging picture provides a unique example in which the alleviation of the Hsp90 ‘capacitor function’ by the environment leads to a morphogenetic shift towards an ancestral-like body plan. The morphogenetic impact of chaperone response during a major setup of epigenetic patterns may be a general scheme for organ reprogramming by environmental cues.
Project description:Proteomics, the temporal study of proteins expressed by an organism, is a powerful technique that can reveal how organisms respond to biological perturbations, such as disease and environmental stress. Yet, the use of proteomics for addressing ecological questions has been limited, partly due to inadequate protocols for the sampling and preparation of animal tissues from the field. Although RNAlater is an ideal alternative to freezing for tissue preservation in transcriptomics studies, its suitability for the field could be more broadly examined. Moreover, existing protocols require samples to be preserved immediately to maintain protein integrity, yet the effects of delays in preservation on proteomic analyses have not been thoroughly tested. Hence, we optimised a proteomic workflow for wild-caught samples. First, we conducted a preliminary in-lab test using SDS-PAGE analysis on aquaria-reared Octopus berrima confirming that RNAlater can effectively preserve proteins up to 6 h after incubation, supporting its use in the field. Subsequently, we collected arm tips from wild-caught Octopus berrima and preserved them in homemade RNAlater immediately, 3 h, and 6 h after euthanasia. Processed tissue samples were analysed by liquid chromatography tandem mass spectrometry to ascertain protein differences between time delay in tissue preservation, as well as the influence of sex, tissue type, and tissue homogenisation methods. Over 3500 proteins were identified from all tissues, with bioinformatic analysis revealing protein abundances were largely consistent regardless of sample treatment. However, nearly 10 % additional proteins were detected from tissues homogenised with metal beads compared to liquid nitrogen methods, indicating the beads were more efficient at extracting proteins. Our optimised workflow demonstrates that sampling non-model organisms from remote field sites is achievable and can facilitate extensive proteomic coverage without compromising protein integrity.
Project description:In CCICs, G9a expression significantly increases K-RAS protein expression but has no effect on mRNA level. This raises the question of whether microRNA (miRNA) is involved in regulation. A heat map of a miRNA array in G9a versus shG9a transfectants ranked the Let-7 family first, with only Let-7b consistently up-regulated in G9a-knockdown CCICs and down-regulated in G9a-overexpressed non-CCICs microRNA array in CRC clinical patientâderived cell line transfected with shRNA against G9a (CCICs/shG9a) or DN-G9a (CCICs/DN-G9a), or in non-CCICs transfected with G9a-expression vector (non-CCICs/G9a).
Project description:Alpha-synuclein (aSyn) is a central player in the pathogenesis of synucleinopathies due to its accumulation in typical protein aggregates in the brain. However, it is still unclear how it contributes to neurodegeneration. Type-2 diabetes mellitus is a risk factor for Parkinson’s disease (PD) and, interestingly, a common molecular alteration among these disorders is the age-associated increase in protein glycation. We hypothesized that glycation-induced neuronal dysfunction might be a contributing factor in synucleinopathies. Here, we dissected the specific impact of methylglyoxal (MGO, a glycating agent) in mice overexpressing aSyn in the brain. We found that MGO-glycation potentiates motor, cognitive, olfactory, and colonic dysfunction in aSyn transgenic (Thy1-aSyn) mice that received a single dose of MGO via intracerebroventricular (ICV) injection. aSyn accumulates in the midbrain, striatum, and prefrontal cortex, and protein glycation is increased in the cerebellum and midbrain. SWATH mass spectrometry analysis, used to quantify changes in the brain proteome, revealed that MGO mainly increase glutamatergic-associated proteins in the midbrain (NMDA, AMPA, glutaminase, VGLUT and EAAT1), but not in the prefrontal cortex, where it mainly affects the electron transport chain. Notably, the glycated proteins in the midbrain of Thy1-aSyn mice that received MGO strongly correlate with PD and dopaminergic pathways. Overall, we demonstrated that MGO-induced glycation accelerates PD-like sensorimotor and cognitive alterations and suggest that the increase of glutamatergic signaling may underly these events. Our study sheds new light into the enhanced vulnerability of the midbrain in PD-related synaptic dysfunction and suggests that glycation suppressors and anti-glutamatergic drugs may hold promise as disease-modifying therapies for synucleinopathies.
Project description:Welan gum is mainly produced by Sphingomonas sp. ATCC 31555 and has broad applications in industry such as that in cement production. Both carbon and nitrogen sources are essential for welan production. However, how nitrogen sources affect the metabolism and gene transcription of welan remains elusive. Here, we used next-generation sequencing RNA-seq to analyze the transcriptome of Sphingomonas sp. ATCC 31555 in the presence of inorganic or organic nitrogen sources. Enriched gene expression and pathway analysis suggest that organic nitrogen sources significantly enhanced the expression of genes in central metabolic pathways of Sphingomonas sp. ATCC 31555 and those critical for welan synthesis compared to that observed using inorganic nitrogen sources. The present study improves our understanding of the molecular mechanism underlying the use of nitrogen in welan synthesis in Sphingomonas sp., as well as provides an important transcriptome resource for Sphingomonas sp. in relation to nitrogen sources. Sphingomonas sp. ATCC 31555 strain (stored in our laboratory) was first seeded in an inoculum medium (20 g/L glucose, 3 g/L yeast extract, 3 g/L malt extract, and 5 g/L fish meal protein peptone, pH 7.0), and then cultured in a fermentation medium containing 40 g/L sucrose, 4.0 g/L nitrogen source, 0.6 g/L KH2PO4, and 0.2 g/L MgSO4.7H2O at 37°C. The nitrogen sources used in the present study were as follows: NaNO3 (4.0 g/L) as inorganic nitrogen (IN), beef extract (4.0 g/L) as organic nitrogen (ON), and NaNO3 (1.5 g/L) + beef extract (2.5 g/L) as complex nitrogen (CN). All cultivations were conducted in flasks with constant rotary shaking at 400â??1,000 rpm and 37°C.