News Article | April 20, 2016
No statistical methods were used to predetermine sample size. The investigators were not blinded to allocation during experiments and outcome assessment C57BL/6 (CD45.2) mice were purchased from Harlan Laboratories (Rehovot, Israel). B6.SJL (CD45.1) mice were bred in-house. Transgenic Ly6a(Sca-1)-EGFP mice and transgenic ROSA26-eYFP (EndoYFP) reporter mice were purchased from Jackson Laboratories. Transgenic nestin-GFP mice were kindly provided by G. N. Enikolopov (Cold Spring Harbour Laboratory, USA). Transgenic c-Kit-EGFP mice were kindly provided by S. Ottolenghi (University of Milano-Bicocca, Italy). Transgenic VE-cadherin (Cdh5, PAC)-CreERT2 mice were kindly provided by R. H. Adams (Max Planck Institute for Molecular Biomedicine, Germany). Conditional mutants carrying loxP-flanked Cxcr4 were provided by D. Scadden (Harvard University, Cambridge, USA). Conditional mutants carrying loxP-flanked Fgfr1 and Fgfr2 (Fgfr1/Fgfr2lox/lox) mice were provided by S. Werner (Institute of Cell Biology, Switzerland) and by D. Ornitz (Washington University School of Medicine, USA). To induce endothelial-specific Cre activity and gene inactivation/expression, adult VE-cadherin(Cdh5, PAC)-CreERT2 mice interbred with Cxcr4lox/lox (EndoΔCxcr4) or Fgfr1/2lox/lox (EndoΔFgfr1/2) or with ROSA26-eYFP mice (EndoYFP) were injected intraperitoneally (i.p.) with Tamoxifen (Sigma, T5648) at 1 mg per mouse per day for 5 days. Mice were allowed to recover for 4 weeks after tamoxifen injections, before euthanasia and experimental analysis. Mice carrying only VE-cadherin (Cdh5, PAC)-CreERT2 transgene or the Cxcr4lox/lox/Fgfr1/2lox/lox mutations were used as wild-typecontrols to exclude non-specific effects of Cre activation or of floxed alleles mutation. The endothelial Fgfr1/2 deletion was confirmed by qRT–PCR measurements of Cxcr4 and Fgfr1/2 mRNA from isolated BMECs. Male and female mice at 8–12 weeks of age were used for all experiments. All mouse offspring from all strains were routinely genotyped using standard PCR protocols. Sample size was limited by ethical considerations and background experience in stem cell transplantation (bone marrow transplantation) which exists in the laboratory for many years and other published manuscripts in the stem cell field, confirming a significant difference between means. No randomization or blinding was used to allocate experimental groups and no animals were excluded from analysis. All mutated or transgenic mouse strains had a C57BL/6 background. All experiments were done with approval from the Weizmann Institute Animal Care and Use Committee. Mice that were maintained at the Weizmann Institute of Science were bred under defined flora conditions. Two-photon in vivo microscopy procedures that were performed in Harvard Medical School were approved by the Institutional Animal Care and Use Committee at Massachusetts General Hospital. AMD3100 (Sigma-Aldrich) 5 mg per kg was used to treat mice by subcutaneous (s.c.) injection. Mice were euthanized 30 min later. Recombinant murine FGF-2 (ProSpec) 200 μg per kg was used to treat mice by i.p. injections for seven consecutive days. Neutralizing rat anti-VE-cadherin antibodies or rat IgG (eBioscience) at 50 μg per mouse per day were used to treat mice by intravenous (i.v.) injections for 2 or 5 days. Neutralizing mouse anti-CXCR4 antibodies (12G5 clone) or mouse IgG (eBioscience) at 50 μg per mouse were administered twice, with a 30 min interval, by intravenous (i.v.) injections. To inhibit ROS production, the antioxidant N-acetyl-l-cysteine (NAC; Sigma-Aldrich) was administered by i.p. injection of 130 mg per kg for 2, 5 or 7 days. Mice were euthanized 2–4 h following the final injection. For standard and confocal fluorescent microscopy, femurs were fixed for 2 h in 4% paraformaldehyde, which was replaced and then the samples were washed with 30% sucrose, embedded in optimum cutting temperature compound, and then snap-frozen in N-methylbutane chilled in liquid nitrogen. Sections (5–10 μm) were generated with a CM1850 Cryostat (Leica) at −25 °C with a tungsten carbide blade (Leica) and a CryoJane tape transfer system (Instrumedics), and were mounted on adhesive-coated slides (Leica), fixed in acetone and air-dried. Sections were stained by incubation overnight at 4 °C with primary antibodies, followed by 1 h incubation of secondary antibody at room temperature and in some cases also nuclei labelling by Hoechst 33342 (Molecular Probes) for 5 min at room temperature. Standard analysis (5–6 μm sections) was performed with Olympus BX51 microscope and Olympus DP71 camera. Confocal analysis (10 μm sections) was performed using a Zeiss LSM-710 microscope. In some cases, for BMBV morphological and phenotypical confocal analysis, femurs and tibias were fixed for 2 h in 4% paraformaldehyde, decalcified with 0.5 M EDTA at 4 °C with constant shaking, immersed into 20% sucrose and 2% polyvinylpyrrolidone (PVP) solution for 24 hours, then embedded and frozen in 8% gelatin (porcine) in presence of 20% sucrose and 2% PVP. Sections (80–300 μm) were generated using low-profile blades on a CM3050 cryostat (Leica). Bone sections were air-dried, permeabilized for 10 min in 0.3% Triton X-100, blocked in 5% donkey serum at room temperature for 30 min, and incubated overnight at 4 °C with primary antibodies. Confocal analysis was performed using a Zeiss LSM-780 microscope. Z-stacks of images were processed and 3D-reconstructed with Imaris software (version 7.00, Bitplane). As previously described4, tile scan images were produced by combining the signal of multiple planes along the Z-stalk of bone sections to allow visualization of the distinct types of bone marrow blood vessels and the cells in their surroundings. For the quantifications of blood vessel diameters, a region of 600–700 μm from the growth plate towards the caudal region was selected and diameters for arterial and sinusoidal blood vessels were calculated using ImageJ software on the high-resolution confocal images. Primary and secondary antibodies and relevant information about them are indicated in Supplementary Table 1. For in vivo ROS detection in bone marrow sections, mice were injected i.p. with hydroethidine (Life Technologies) 10 mg per kg, 30 min before euthanasia. For in vivo LDL-uptake detection in bone marrow sections, mice were i.v. injected with Dil-Ac-LDL (BTI) 20 μg per mouse, 4 h before euthanasia. Femurs were immediately collected and processed as mentioned earlier. Bone marrow section analysis for scoring ROShigh cells was performed using ImageJ software (Extended Data Fig. 1). Multiple sections (>16 per mouse) were generated and analysed from at least 4 mice per group of experimental procedure, in order to confirm biological repeats of the observed data. In some cases, images were processed to enhance the contrast in order to allow better evaluation of co-localization of cellular borders and markers. Imaris, Volocity (Perkin Elmer), Photoshop and Illustrator (Adobe) software were used for image processing. For blood vessel imaging in the calvarium of Sca-1-EGFP and nestin-GFP mice, we used a microscope (Ultima Multiphoton; Prairie Technologies) incorporating a pulsed laser (Mai Tai Ti-sapphire; Newport Corp.). A water-immersed 20× (NA 0.95) or 40× (NA 0.8) objective (Olympus) was used. The excitation wavelength was set at 850–910 nm. For intravital imaging, mice were anaesthetized with 100 mg ketamine, 15 mg xylazine and 2.5 mg acepromazine per kg. During imaging, mice were supplied with oxygen and their core temperature was maintained at 37 °C with a warmed plate. The hair on the skullcap was trimmed and further removed using urea-containing lotion and the scalp was incised at the midline. The skull was then exposed and a small steel plate with a cut-through hole was centred on the frontoparietal suture, glued to the skull using cyanoacrylate-based glue and bolted to the warmed plate. To visualize blood vessels, mice were injected i.v. with 2 μl of a 2 μM non-targeted nanoparticles solution (Qtracker 655, Molecular Probes). In some cases, mice were i.v. injected with Dil-Ac-LDL (BTI) 40 μg per mouse, 2 h before their imaging. We typically scanned a 50 μm-thick volume of tissue at 4 μm Z-steps. Movies and figures based on two-photon microscopy were produced using Volocity software (Perkin Elmer). For live imaging of blood vessels permeability and leukocyte bone marrow trafficking, a previously described experimental procedures and a home built laser-scanning multiphoton imaging system29, were used with some modifications. Anaesthesia was slowly induced in mice via inhalation of a mixture of 1.5–2% isoflurane and O . Once induced, the mixture was reduced to 1.35% isoflurane. By making a U-shaped incision on the scalp, calvarial bone was exposed for imaging and 2% methocellulose gel placed on it for refractive index matching. For bone marrow blood vessel permeability studies, mice were positioned in heated skull stabilization mount which allowed access to the eye for on-stage retro-orbital injection of 40–60 μl of 10 mg ml−1 70 kDa rhodamine-dextran (Life Technologies). Nestin-GFP (excited at 840 nm) and confocal reflectance (at 840 nm) signals were used to determine a region of interest within the mouse calvarial bone marrow for measurement of permeability. Rhodamine-dextran was injected and was continuously recorded (30 frames per second) for the first 10 min after injection. After video acquisition, mice were removed from the microscope and euthanasized with CO . In some cases, following dextran clearance, the same mice were used for homing experiments to monitor leukocyte cell trafficking in regions and blood vessels that were defined as less or more permeable. For cell homing studies, mice were injected with 2 × 106 DiD-labelled (Life Technologies) lineage depleted immature haematopoietic progenitor cells (Miltenyi depletion) and with 2 × 106 DiI-labelled (Life Technologies) bone marrow MNC isolated from age matched C57BL/6 mice along with 150 μl of 2 nmol per 100 μl Angiosense 750EX (Perkin Elmer) fluorescent blood pool imaging agent, immediately before mounting the mice on a heated stage of a separate confocal/multiphoton microscope. Intravital images of the mouse bone marrow were collected for up to the first 3 h after injection of the cells. After imaging, the mice were removed from the microscope and euthanized with CO . Permeability, blood flow/shear rates and homing experiments were repeated, n = 3 mice each, measuring multiple blood vessels and events, each mouse regarded as an independent experiment, in order to confirm biological repeats of the observed data. The contrast and brightness settings of the images in the figures were adjusted for display purposes only. For permeability studies, the RGB movies were separated into red (Rhodamine-Dextran), green (nestin-GFP), and blue (reflectance) grayscale image stacks. An image registration algorithm (Normalized Correlation Coefficient, Template Matching) was performed on the red stack using ImageJ (v. 1.47p) to minimize movement artefacts within the image stack. Manual selection of regions of interest (ROI) was performed immediately next to individual vessels within the focus. Permeability of the vessels was calculated using the following equation: P is the permeability of the vessel, V is the volume of the ROI next to the vessel, A is the fractional surface area of the vessel corresponding to the ROI, dI/dt is the intensity of the dye in the ROI as a function of time, I is the intensity of the dye inside the corresponding vessel at the beginning of measurement, and I is the intensity of the dye in the ROI at the beginning of measurement. To calculate dI/dt for a given vessel, the change in intensity was measured within the ROI over time and linearly fit the first ~5–40 s of the data. The slope of this linear fit is dI/dt. The ROI intensity curve is only linear for the first 30–40 s, after which it begins to plateau. For cell homing, the number of stationary cells from the calvarial bone marrow images was counted and categorized into two groups: adherent and extravasated. We categorized both cells within the lumen of the vessel and cells in the process of transmigration in the adherent category. Maximum intensity projections of multiple z-stacks of images were used to count the number of cells in the two categories. When there was a gap between cells and vessels in the two-dimensional projection image, those cells were categorized as extravasated. If any part of a cell overlapped a vessel in the projection image, the corresponding three dimensional z-stack was viewed to determine if the cell had undergone extravasation. When it was unclear if a cell had extravasated, it was always categorized as adherent. For the flow speed measurement, red blood cells (RBCs) were labelled with 15 μM CFSE for 12 min at 37 °C in PBS supplemented with 1 g per litre of glucose and 0.1% BSA. About 0.6 billion RBCs were injected (i.v). 40 μl of rhodamineB-dextran 70 kDa (10 mg ml−1) was retro-orbitally injected immediately before imaging for visualizing bone marrow vasculature. Videos of confocal images of blood vessel (RhodamineB, excitation: 561 nm, emission: 573–613 nm) and labelled RBCs (CFDA-SE, excitation: 491 nm, emission: 509–547 nm) were taken with the speed of 120 frames per second. Individual RBCs were traced over a couple of frames. Total displacement of the RBCs was measured by ImageJ and the speed of blood flow was calculated by: To calculate the shear rate, we assumed that the vessels were straight (straight cylinder) and the blood is an ideal Newtonian fluid with constant viscosity. Under these conditions, the shear rate (du/dr) can be calculated by du/dr = 8×u/d (u is the average blood flow speed which was measured by tracing labelled RBCs and d is the diameter of the blood vessel as measured using ImageJ). Immunostaining signal intensity was analysed with MacsQuant (Miltenyi, Germany) or with a FACS LSRII (BD Biosciences) with FACSDiva software, data were analysed with FlowJo (Tree Star). Data of the expression of molecules by cells was analysed and presented as MFI (mean fluorescent intensity). To acquire single bone marrow cell suspensions, freshly isolated bones were cleaned, flushed and crushed using liver digestion medium (LDM, Invitrogen) supplemented with 0.1% DNaseI (Roche) and further digested for 30 min at 37 °C, under shaking conditions. Following the incubation time, cells were filtered and washed extensively. To isolate and acquire mononuclear cells (MNC) from the peripheral blood PB, blood was collected from the heart using heparinized syringes and MNC were separated using Lymphoprep (Axis-Shield) according to the manufacturer’s instructions. Isolated bone marrow and peripheral blood MNC cells underwent red blood cell lysis (Sigma) before staining. Cells were stained for 30 min at 4 °C in standard flow cytometry buffer with primary antibodies and, where indicated, with secondary antibodies. Information about the primary and secondary antibodies can be found in the antibody information (Supplementary Table 1). For antigens that required intracellular staining, cell surface staining was followed by cell fixation and permeabilization with the Cytofix/Cytoperm kit following the manufacturer’s instructions (BD Biosciences). In case of internal GFP labelled cells, cells were fixed for 20 min with 4% PFA at room temperature, washed and incubated at room temperature for 1 h in 30% sucrose. Cells were washed with flow cytometry buffer and further permeabilized. For intracellular ROS detection, cells were incubated for 10 min at 37 °C with 2 μM hydroethidine (Life Technologies). For glucose uptake detection, cells were incubated for 30 min at 37 °C with the glucose analogue 2-NBDG (Life Technologies). For detection of apoptotic cells, cells were resuspended in annexinV binding buffer (BioLegend) and stained with Pacific Blue AnnexinV (BioLegend). Bone marrow cells were enriched for the lineage negative population, prepared as indicated for flow cytometry and analysed using an ImageStreamX (Amnis) machine. Samples were visualized and analysed for the expression of markers and antigens with IDEAS 4.0 software (Amnis). Single-stained control cells were used to compensate fluorescence between channel images. Cells were gated for single cells with the area and aspect ratio features or, for focused cells, with the Gradient RMS feature. Cells were then gated for the selection of positively stained cells only with their pixel intensity, as set by the cutoff with IgG and secondary antibody control staining. At least 5 samples from 5 mice were analysed to confirm biological repeats of observed data. Detection of mouse calcitonin (Cusabio) and mouse PTH (Cloud-Clone Corp.) levels in bone marrow supernatants was performed according to the manufacturer’s instructions. CFU-GM and CFU-F assays were previously described34. For CFU-Ob assay (also known as mineralized nodule formation assay), CFU-F medium was supplemented with 50 μg ml−1 ascorbic acid and with 10 mM β-glycerophosphate. After 3 weeks, cultures were washed, fixed and stained using Alizarin red for mineralized matrix. The area of mineralized nodules per cultured well was quantified based on image analysis using ImageJ. Bone marrow cells were isolated after sterile bone flushing, crushing and digestion (as previously described). After washing, total bone marrow cells were incubated in medium supplemented with or without 25% blood plasma or supplemented with 20 ng ml−1 TGF-β1 (ProSpec) for 2 h. Plasma was isolated and collected from the upper fraction acquired from the peripheral blood after 5 min centrifugation at 1,500 r.p.m. Bone marrow vascular endothelial barrier function was assessed using the Evans Blue Dye (EBD) assay. Evans Blue (Sigma-Aldrich) 20 mg per kg was injected i.v. 4 h before mice were euthanized. In each experiment, a non-injected mouse was used for control blank measurements. Subsequently, mice were perfused with PBS via the left ventricle to remove intravascular dye. Femurs were removed and formamide was used for bone flushing, crushing and chopping. EBD was extracted in formamide by incubation and shaking of flushed and crushed fractions, overnight at 60 °C. After 30 min centrifugation at 2,000g, EBD in bone marrow supernatants was quantitated by dual-wavelength spectrophotometric analysis at 620 nm and 740 nm. This method corrects the specimen’s absorbance at 620 nm for the absorbance of contaminating haem pigments, using the following formula: corrected absorbance at 620 nm = actual absorbance at 620 nm – (1.426(absorbance at 740) + 0.03). Samples were normalized by subtracting control measurements. Levels of EBD bone marrow penetration per femur were expressed as OD /femur and the fold change in EBD bone marrow penetration was calculated by dividing the controls OD /femur from the treated OD /femur in each experiment. Finally, values were normalized per total protein extract as determined by Bradford assay per sample. For competitive LTR assay, B6.SJL (CD45.1) recipient mice were lethally irradiated (1,000 cGy from a caesium source) and injected 5 h later with 2 × 105 donor-derived (C57BL/6 background, CD45.2) bone marrow cells or with 500 μl of donor-derived whole blood together with 4 × 105 recipient derived (CD45.1) bone marrow cells. Recipient mice were euthanized 24 weeks after transplantation to determine chimaerism levels using flow cytometry analysis. For calculation of competitive repopulating units (CRU), recipient mice were transplanted with limiting dilutions of donor derived bone marrow cells (2.5 × 104 to 2 × 105) together with 2 × 105 recipient derived bone marrow cells. Mice were euthanized after 24 weeks and multi-lineage myelo-lymphoid donor derived contribution in the peripheral blood was assessed using flow cytometry analysis. HSC-CRU frequency and statistical significance was determined using ELDA software (http://bioinf.wehi.edu.au/software/elda/). Lineage negative cells were enriched from total bone marrow cells, taken from c-Kit-EGFP mice, using mouse lineage depletion kit (BD) according to the manufacturer’s instructions. Non-irradiated recipient mice were transplanted by i.v. injection with 2 × 106 c-Kit-EGFP-labelled Lin− cells. Recipient mice were euthanized 4 h after transplantation. Bone marrow cells were isolated from femurs and stained for flow cytometry as described above. Femur cellularity was determined in order to calculate the number of homed CD34−/LSK HSPC per femur. For magnetic isolation of BMECs, freshly recovered bones were processed under sterile conditions as described for BMECs flow cytometry analysis, and post-digestion incubated with biotin rat anti-mouse CD31 antibodies (BD pharmigen) for 30 min at 4 °C. Next, cells were washed and incubated with streptavidin particles plus (BD IMag) for 30 min at 4 °C. Positive selection was performed using BD IMagnet (BD) according to the manufacturer’s instructions (BD Biosciences). BD IMag buffer (BD) was used for washing and for antibodies dilution. Isolated cells were seeded on fibronectin (Sigma-Aldrich) coated wells and cultured overnight in EBM-2 medium (Lonza) supplemented with EGM-2 SingleQuots (Lonza) at 37 °C 5% CO . Non-adhesive cells were removed and adherent cells were collected using accutase (eBioscience). Flow cytometry was applied to confirm endothelial identity and >90% purity of recovered cells. BMEC were further processed to isolate RNA. Total RNA was isolated using TRI-Reagent (Sigma-Aldrich) according to the manufacturer’s protocol. An aliquot of 2 μg of total RNA was reverse-transcribed using Moloney murine leukaemia virus reverse transcriptase (Promega, Madison, WI) and oligo-dT primers (Promega). Quantitative reverse transcribed–polymerase chain reaction (qRT–PCR) was done using the ABI 7000 machine (Applied Biosystems, Foster City, CA) with SYBR Green PCR Master Mix (Applied Biosystems). Comparative quantization of transcripts was assessed relative to hypoxanthine phosphoribosyl transferase (Hprt) levels and amplified with appropriate primers. Primer sequences used were as follows (mouse genes): Cxcr4 forward 5′- ACGGCTGTAGAGCGAGTGTT-3′; reverse 5′- AGGGTTCCTTGTTGGAGTCA-3′; Fgfr1 forward 5′-CAACCGTGTGACCAAAGTGG-3′; reverse 5′-TCCGACAGGTCCTTCTCCG-3′; Fgfr2 forward 5′-ATCCCCCTGCGGAGACA-3′; reverse 5′-GAGGACAGACGCGTTGTTATCC-3′; Hprt forward 5′-GCAGTACAGCCCCAAAATGG-3′; reverse 5′-GGTCCTTTTCACCAGCAAGCT-3′. All statistical analyses were conducted with Prism 4.0c version or Excel (*P < 0.05, **P < 0.01, ***P < 0.005; NS, not significant). All data are expressed as mean ± standard error (s.e.m) and all n numbers represent biological repeats. Unless indicated otherwise in figure legends, a Student’s two-tailed unpaired t-test was used to determine the significance of the difference between means of two groups. One-way ANOVA or two-way ANOVA was used to compare means among three or more independent groups. Bonferroni post-hoc tests were used to compare all pairs of treatment groups when the overall P value was <0.05. A normal distribution of the data was tested using the Kolmogorov–Smirnov test if the sample size allowed. If normal-distribution or equal-variance assumptions were not valid, statistical significance was evaluated using the Mann–Whitney test and the Wilcoxon signed rank test. Animals were randomly assigned to treatment groups. Tested samples were assayed in a blinded fashion.
Bayne E.H.,Institute of Cell Biology |
White S.A.,Institute of Cell Biology |
Kagansky A.,Institute of Cell Biology |
Bijos D.A.,Institute of Cell Biology |
And 7 more authors.
Cell | Year: 2010
In fission yeast, RNAi directs heterochromatin formation at centromeres, telomeres, and the mating type locus. Noncoding RNAs transcribed from repeat elements generate siRNAs that are incorporated into the Argonaute-containing RITS complex and direct it to nascent homologous transcripts. This leads to recruitment of the CLRC complex, including the histone methyltransferase Clr4, promoting H3K9 methylation and heterochromatin formation. A key question is what mediates the recruitment of Clr4/CLRC to transcript-bound RITS. We have identified a LIM domain protein, Stc1, that is required for centromeric heterochromatin integrity. Our analyses show that Stc1 is specifically required to establish H3K9 methylation via RNAi, and interacts both with the RNAi effector Ago1, and with the chromatin-modifying CLRC complex. Moreover, tethering Stc1 to a euchromatic locus is sufficient to induce silencing and heterochromatin formation independently of RNAi. We conclude that Stc1 associates with RITS on centromeric transcripts and recruits CLRC, thereby coupling RNAi to chromatin modification. © 2010 Elsevier Inc. All rights reserved.
News Article | February 24, 2017
Researchers at the University of Tübingen, working with colleagues in other parts of Germany and in the United States, have identified an enzyme as a kind of biological gauge regulating inflammation in the human body. Professor Alexander Weber of the Interfaculty Institute of Cell Biology says the enzyme - Bruton's tyrosine kinase or BTK - is switched on when an inflammation occurs in the body, playing a key role in the inflammation's subsequent development. Inflammation is an important for recovery mechanism from many diseases. Yet in disorders like gout, Alzheimer's, atherosclerosis, heart attack or stroke, inflammation can also have negative effects and reinforce the damage done by the disease. Inflammation is driven - among other processes - by molecular machinery known as the inflammasome. First, immune cells are activated which release certain inflammation-promoting messenger proteins, called cytokines. "Because there is a lot we don't know about how inflammasomes function, there are no currently available treatments to curb inflammation which would directly block this molecular machinery," Weber explains. Treatments available to date focus instead on later phases or symptoms of an inflammation. This gap in the treatment options motivated the Tübingen researchers to investigate inflammasomes more closely in the search for new ways to directly repress inflammation at the outset. In the course of their work, Weber's team discovered the function of the BTK protein as a kind of biochemical faucet, turning on the flow of the inflammasome in human immune cells. "Bruton's tyrosine kinase has been known for many years as the genetic cause of the very rare Bruton syndrome, an immunodeficiency," says Xiao Liu, a doctoral candidate on the team. Bruton syndrome patients lack B lymphocyte white blood cells - and therefore antibodies which are normally produced by them - because BTK regulates their maturation and functions. Together with their colleagues in Bonn, Freiburg, Ulm and across the Altlantic in Baltimore, the Tübingen researchers demonstrated that BTK is a component of inflammosomes; and that patients with a BTK mutation - Bruton syndrome - also have a defect in their inflammasome. Weber says this might take us a step closer to a new approach to treating inflammation. Medications which inhibit the effects of BTK have been applied lately for treating a certain type of lymphoma caused by cancerous B lymphocytes. "We demonstrated that an experimental inhibition of BTK strongly reduced inflammation," Weber says. The inflammatory cytokine Interleukin-1 is effectively blocked in immune cells of cancer patients on BTK inhibitors and in their cells the inflammasome is virtually shut down. "This means that patients suffering the aftereffects of a stroke, heart attack, or who have gout may well benefit from the use of BTK inhibitors in the future," Weber says, as the inflammasome appears to make the disease worse in such cases. "Our results and those provided by other colleagues are a good starting point to explore the possibilities in further experimental research and clinical studies," the scientists say. Article: Human NLRP3 inflammasome activity is regulated by and potentially targetable via BTK, Liu X, Pichulik P, Wolz OO, Dang TM, Stutz A, Page C, Delmiro Garcia M, Kraus H, Dickhöfer S, Daiber E, Münzenmayer L, Wahl S, Rieber N, Kümmerle-Deschner J, Yazdi A, Franz-Wachtel M, Macek B, Radsak M, Schulte S, Stickel JS, Hartl D, Latz E, Grimbacher B, Miller L, Brunner C, Wolz C, Weber AN., Journal of Allergy and Clinical Immunology, doi: 10.1016/j.jaci.2017.01.017, published online 16 February 2017.
Desoye G.,Institute of Cell Biology |
Gauster M.,Medical University of Graz |
Wadsack C.,Institute of Cell Biology
American Journal of Clinical Nutrition | Year: 2011
The placenta is positioned between the maternal and fetal circulation and hence plays a key role in transporting maternal nutrients to the developing fetus. Fetal growth changes in the 2 most frequent pregnancy pathologies, gestational diabetes mellitus and fetal growth restriction, are predominantly characterized by an exaggerated and restricted fat accretion, respectively. Glucose, by its regulating effect on fetal insulin concentrations, and lipids have been strongly implicated in fetal fat deposition. Transplacental glucose flux is highly efficient and limited only by nutrient availability (flow-limited)-ie, driven by the maternal-fetal glucose concentration gradient and blood flow, with little, if any, effect of placental morphology, glucose consumption, and transporter expression. This explains why, despite changes in these determinants in both pathologies, transplacental glucose flux is unaltered. © 2011 American Society for Nutrition.
Rammensee H.-G.,Institute of Cell Biology |
Singh-Jasuja H.,immatics biotechnologies
Expert Review of Vaccines | Year: 2013
Every cancer is different and cancer cells differ from normal cells, in particular, through genetic alterations. HLA molecules on the cell surface enable T lymphocytes to recognize cellular alterations as antigens, including mutations, increase in gene product copy numbers or expression of genes usually not used in the adult organism. The search for cancer-associated antigens shared by many patients with a particular cancer has yielded a number of hits used in clinical vaccination trials with indication of survival benefit. Targeting cancer-specific antigens, which are exclusively expressed on cancer cells and not on normal cells, holds the promise for much better results and perhaps even a cure. Such antigens, however, may specifically appear in very few patients or may be mutated appearing just in one patient. Therefore, to target these in a molecularly defined way, the approach has to be individualized. © 2013 Informa UK Ltd.
News Article | November 16, 2016
New research in The FASEB Journal suggests that induction of p53 (a potent tumor suppressor) not only may prevent cancer, but also is required for the fasting-induced adaptation of nutrient metabolism Could limiting food intake be a valid treatment strategy for certain types of cancers? New research in The FASEB Journal suggests "maybe." In a report appearing online in The FASEB Journal, scientists show that food restriction increases levels of a tumor-suppressing molecule, called p53, in both hepatocytes grown in the laboratory and in mouse liver. In addition, this research gives evidence that p53-induction is required for the fasting-induced adaptation of nutrient metabolism. "Metabolic diseases and cancer are major health burdens in our societies," said Andreas Prokesch, Ph.D., study author and Associate Professor at the Institute of Cell Biology, Histology, and Embryology at the Medical University of Graz in Graz, Austria. "We hope that our study will yield new therapeutic concepts to fight these diseases." To make their discovery, Prokesch and colleagues first determined the abundance of p53 protein in the livers of mice with free access to food compared to mice that had food withheld for 24 hours. They found that there was a strong induction of p53 protein in the livers of the mice that had undergone food withdrawal. This p53 accumulation was also observed in cultured mouse or human hepatocytes upon the removal of nutrients from their culture media. The researchers then compared blood glucose and amino acid utilization in the livers of mice with or without acute inactivation of the p53 gene. Mice that lacked p53 in the liver showed reduced blood glucose levels and altered hepatic amino acid metabolism during starvation. "Connections between nutrients and tumor suppression have long been known, but this study adds a sharp focal point," said Thoru Pederson, Ph.D., Editor-in-Chief of The FASEB Journal. "The altered amino acid metabolism observed is especially provocative, as that is a rapidly emerging area of interest in tumor biochemistry." Submit to The FASEB Journal by visiting http://fasebj. , and receive monthly highlights by signing up at http://www. . The FASEB Journal is published by the Federation of the American Societies for Experimental Biology (FASEB). It is the world's most cited biology journal according to the Institute for Scientific Information and has been recognized by the Special Libraries Association as one of the top 100 most influential biomedical journals of the past century. FASEB is composed of 30 societies with more than 125,000 members, making it the largest coalition of biomedical research associations in the United States. Our mission is to advance health and welfare by promoting progress and education in biological and biomedical sciences through service to our member societies and collaborative advocacy. Details: Andreas Prokesch, Franziska A. Graef, Tobias Madl, Jennifer Kahlhofer, Steffi Heidenreich, Anne Schumann, Elisabeth Moyschewitz, Petra Pristoynik, Astrid Blaschitz, Miriam Knauer, Matthias Muenzner, Juliane G. Bogner-Strauss, Gottfried Dohr, Tim J. Schulz, and Michael Schupp. Liver p53 is stabilized upon starvation and required for amino acid catabolism and gluconeogenesis. FASEB J. doi:10.1096/fj.201600845R ; http://www.
Paksa A.,Institute of Cell Biology |
Raz E.,Institute of Cell Biology
Current Opinion in Cell Biology | Year: 2015
In the course of embryonic development, the process of cell migration is critical for establishment of the embryonic body plan, for morphogenesis and for organ function. Investigating the molecular mechanisms underlying cell migration is thus crucial for understanding developmental processes and clinical conditions resulting from abnormal cell migration such as cancer metastasis. The long-range migration of primordial germ cells toward the region at which the gonad develops occurs in embryos of various species and thus constitutes a useful in vivo model for single-cell migration. Recent studies employing zebrafish embryos have greatly contributed to the understanding of the mechanisms facilitating the migration of these cells en route to their target. © 2015 .
Mickoleit M.,Institute of Cell Biology |
Banisch T.U.,Institute of Cell Biology |
Raz E.,Institute of Cell Biology
Developmental Dynamics | Year: 2011
The Hu proteins are RNA-binding proteins known to be involved in various aspects of RNA metabolism, such as nucleo-cytoplasmic shuttling, translation, and stability. These proteins are predominantly expressed in neuronal tissues and are important for neuronal differentiation and plasticity. Here, we report on the regulation over hub mRNA stability and function in zebrafish embryos. Using reporters encoding for fluorescent proteins, we show that hub RNA is a target of global miRNA-mediated repression, while the RNA-binding protein Dead end (Dnd) contributes to maintenance of the expression in the primordial germ cells (PGCs). Developmental Dynamics 240:695-703, 2011. © 2011 Wiley-Liss, Inc.
Reichman-Fried M.,Institute of Cell Biology |
Raz E.,Institute of Cell Biology
BioEssays | Year: 2014
The identification of molecules controlling embryonic patterning and their functional analysis has revolutionized the fields of Developmental and Cell Biology. The use of new sequence information and modern bioinformatics tools has enriched the list of proteins that could potentially play a role in regulating cell behavior and function during early development. The recent application of efficient methods for gene knockout in zebrafish has accelerated the functional analysis of many proteins, some of which have been overlooked due to their small size. Two recent publications report on the identification of one such protein and its role in zebrafish embryogenesis. The protein, currently designated Apela, was shown to act as a secreted protein whose absence adversely affected various early developmental processes. Additional signaling proteins that have been identified in one of the studies are likely to open the way to unraveling hitherto unknown developmental pathways and have the potential to provide a more comprehensive understanding of known developmental processes. © 2014 WILEY Periodicals, Inc.
Zupancic D.,Institute of Cell Biology |
Kreft M.E.,Institute of Cell Biology |
Romih R.,Institute of Cell Biology
Protoplasma | Year: 2014
Bladder cancer adjuvant intravesical therapy could be optimized by more selective targeting of neoplastic tissue via specific binding of lectins to plasma membrane carbohydrates. Our aim was to establish rat and mouse models of bladder carcinogenesis to investigate in vivo and ex vivo binding of selected lectins to the luminal surface of normal and neoplastic urothelium. Male rats and mice were treated with 0.05 % N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in drinking water and used for ex vivo and in vivo lectin binding experiments. Urinary bladder samples were also used for paraffin embedding, scanning electron microscopy and immunofluorescence labelling of uroplakins. During carcinogenesis, the structure of the urinary bladder luminal surface changed from microridges to microvilli and ropy ridges and the expression of urothelial-specific glycoproteins uroplakins was decreased. Ex vivo and in vivo lectin binding experiments gave comparable results. Jacalin (lectin from Artocarpus integrifolia) exhibited the highest selectivity for neoplastic compared to normal urothelium of rats and mice. The binding of lectin from Amaranthus caudatus decreased in rat model and increased in mouse carcinogenesis model, indicating interspecies variations of plasma membrane glycosylation. Lectin from Datura stramonium showed higher affinity for neoplastic urothelium compared to the normal in rat and mouse model. The BBN-induced animal models of bladder carcinogenesis offer a promising approach for lectin binding experiments and further lectin-mediated targeted drug delivery research. Moreover, in vivo lectin binding experiments are comparable to ex vivo experiments, which should be considered when planning and optimizing future research. © 2013 Springer-Verlag Wien.