Project description:Heart failure is a leading cause of mortality and morbidity in the developed world, partly because mammals lack the ability to regenerate heart tissue. Whether this is due to evolutionary loss of regenerative mechanisms present in other organisms or to an inability to activate such mechanisms is currently unclear. Here, we decipher mechanisms underlying heart regeneration in adult zebrafish and show that the molecular regulators of this response are conserved in mammals. We identified miR-99/100 and Let-7a/c, and their protein targets smarca5 and fntb, as critical regulators of cardiomyocyte dedifferentiation and heart regeneration in zebrafish. Although human and murine adult cardiomyocytes fail to elicit an endogenous regenerative response following myocardial infarction, we show that in vivo manipulation of this molecular machinery in mice results in cardiomyocyte dedifferentiation and improved heart functionality after injury. These data provide a proof-of-concept for identifying and activating conserved molecular programs to regenerate the damaged heart. Analysis of miRNA levels in regenerating zebrafish hearts
Project description:Fish scales are an important reservoir of calcium and phosphorus and together with the skin function as an integrated barrier against environmental changes and external aggressors. Histological studies have revealed that the skin and scales regenerate rapidly in fish when they are lost or damaged. In the present manuscript the histological and molecular changes underlying skin and scale regeneration in fed and fasted sea bream (Sparus auratus) were studied using a microarray 3 and 7 days after scale removal to provide a comprehensive molecular understanding of the early stages of these processes. Histological analysis of skin/scales revealed 3 days after scale removal re-epithelisation had occurred and the scale pocket had formed. In animals with scales removed, there was significant up-regulation of genes involved in cell cycle regulation, cell proliferation and adhesion, immune response and antioxidant activities. The expression profiles of the fasted animals centred on maintaining energy homeostasis. The utilisation of fasting as a treatment emphasised the competing whole animal physiological requirements with regard to barrier repair, infection control and energy homeostasis. Gene expression of sea bream (Sparus auratus) skin and scales was analysed in normal and treated animals. Three different treatments were applied: 1. scales removal at day 0 of the experiment; 2. unfed fish 7 days prior the start of the experiment; and 3. scales removal at day 0 of the experiment of unfed fish 7 days prior the start of the experiment. Fish were sampled at two different days: day 3 and day 7 after scale removal. Five individuals from control and experimental groups were analysed for both sampling days (3 and 7), resulting in a total of 40 samples analysed by microarray.
Project description:The gene expression profile of the adult zebrafish cornea was assessed in comparison to those from closely associated surface tissues: the dermis and epidermis. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
Project description:A transgenic line cmlc2:TRAP was made to express EGFP-fused ribosomal protein L10a (EGFP-L10a) in zebrafish cardiomyocytes. Then ribosome-associated RNAs were immuoprecipitated from uninjured and injured adult cmlc2:TRAP fish to determine the differential expression changes during zebrafish heart regeneration. A nine chip study with cardiomyocyte ribosome associated RNAs purified from three separate isolation of uninjured adult cmlc2:TRAP fish hearts, three separate isolation of 1 day post amupation (dpa) adult cmlc2:TRAP fish hearts, and three separate isolation of 7 dpa adult cmlc2:TRAP fish hearts.
Project description:The myeloma cell line RPMI 8226/S and its doxorubicin resistant subline 8226/Dox40 were used as models to explore the potential importance of the STAT1 signaling pathway in drug and radiation resistance. The 40-fold doxorubicin resistant subline 8226/Dox40 was found to be crossresistant to single doses of 4 and 8 Gy of radiation. A genome-wide mRNA expression study comparing the 8226/Dox40 cell line to its parental line was performed to identify the underlying molecular mechanisms. Seventeen of the top 50 overexpressed genes have previously been implicated in the STAT1 signaling pathway. STAT1 was over expressed both at the mRNA and protein level. Moreover, analyses of nuclear extracts showed higher abundance of phosphorylated STAT1 (Tyr 701) in the resistant subline. Preexposure of the crossresistant cells to the STAT1 inhibiting drug fludarabine reduced expression of overexpressed genes and enhanced the effects of both doxorubicin and radiation. These results show that resistance to doxorubicin and radiation is associated with increased STAT1 signaling and can be modulated by fludarabine. The data support further development of therapies combining fludarabine and radiation.
Project description:Purpose: To identify genes and molecular mechanisms associated with disease progression during (7 weeks of age) and after (16 weeks) the peak of photoreceptor death in dogs affected with XLPRA2, a canine model of early-onset XLRP caused by a microdeletion in RPGR exon ORF15. Methods: Expression profiles of diseased and normal dog retinas at both ages were compared using a canine retinal custom cDNA microarray. Data normalization and filtering were performed with GeneSpring, statistical analysis with Significance Analysis of Microarrays. Real-time PCR using Taqman probes, western blot and immunohistochemistry (IHC) were applied on selected genes to confirm and expand the microarray results. Results: At 7 and 16 weeks, respectively, 56 and 18 transcripts were down-regulated in mutant retinas compared to normals. None of the transcripts was differentially expressed (DE) at both ages, suggesting the involvement of temporally distinct molecular pathways. Down-regulated genes included PAX6, CHML, and RDH11 at 7 weeks and CRX and SAG at 16 weeks, which are necessary for visual system development and function. Genes directly or indirectly active in apoptotic processes were altered at 7 weeks (CAMK2G, NTRK2, PRKCB, RALA, RBBP6, RNF41, SEPT5, SMYD3, SPP1, and TUBB2C) and 16 weeks (SLC25A5 and NKAP). Furthermore, DE genes at 7 weeks (ELOVL6, GLOD4, NDUFS4, and REEP1) and 16 weeks (SLC25A5 and TARS2) are related to mitochondrial functions. Real-time PCR of 11 genes confirmed the microarray results and showed differential expression for additional genes not on the array, such as GFAP, RHO, OPN1SW, CNGB3 and the mutated RPGR. Western blotting and IHC analysis also confirmed the high reliability of the presented transcriptomic data. Conclusions: A list of mutated genes in RPGRORF15 diseased retinas, which are likely candidates to further study their role in age-related photoreceptor degeneration diseases, is reported at different crucial ages. The results indicate that at 7 weeks a combination of non-classical anti- and pro-apoptotic genes appears to be involved in photoreceptor degeneration, whereas at both 7 and 16 weeks expression of mitochondria related genes indicates they may play a relevant role in the disease process. 3 biological replicates each for normal and XLPRA2 affected retinas were analyzed at 7 and 16 weeks of age. Each individual sample was hybridized in a reference design using a custom-made retinal cDNA microarray against brain pool to enable cross comparison between groups. Retina was labeled with Cy5 in all samples but 5615 (GSM474350).
Project description:The objective of this study was to determine the effects of miR-106a~363 blockade on the gene expression profile of Ewing Sarcoma cell lines (Sk-ES-1 cells) Microarray analysis was performed on 3 samples from Sk-ES-1 cells stably expressing the control CXCR4 miRNA sponge and 3 samples from Sk-ES-1 cells stably expressing the miR-106a~363 cluster blocking miRNA sponge
Project description:Several recent reports show that the cerebral cortex in humans and animals with altered expressions of Wnt/cadherin network-associate molecules display cytoarchitectural abnormalities reminiscent of cortical dysplasias seen in some (mouse-, rat-, and monkey-based) animal models of prenatal cocaine exposure. Therefore, we employed oligo microarrays followed by real-time RT-PCR to compare expressions of genes involved in Wnt and cadherin systems in the cerebral wall of 18-day-old (E18) fetuses from cocaine-treated (20 mg/kg cocaine, s.c., b.i.d., E8-18) and drug-naive (saline, s.c.) mice. The pregnant mice chronically treated with cocaine in the above-described manner represent one of the animal models producing offspring with widespread cortical dysplasias. Out of more than 150 relevant genes in the arrays, 32 were upregulated and 9 were downregulated in cocaine-exposed fetuses. The majority of these genes (30 out of 41) were similarly affected in the frontal and occipital regions of the cerebral wall. We also used Western immunoblotting to examine the ability of cocaine to regulate the protein levels of beta-catenin, the key functional component of both Wnt and cadherin systems. While the total cell levels of beta-catenin were increased throughout the cerebral wall of cocaine-exposed fetuses, its nuclear (gene-transcription driving) levels remained unaltered. This suggests a transcription-unrelated role for cocaine-induced upregulation of this protein. Overall, our findings point to an intriguing possibility that that cerebral cortical dysplasias observed in several animal models of prenatal cocaine exposure may be at least in part related to alterations in the Wnt/cadherin molecular network. It has been demonstrated that exposure to cocaine increases cell death in the fetal CNS. To examine the molecular mechanisms of this effect, we employed mouse oligo microarrays followed by real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) to compare expressions of apoptosis-related genes in the cerebral wall of 18-day-old (E18) fetuses from cocaine-treated (20 mg/kg cocaine, s.c., b.i.d., E8th-E18th) and drug-naive (saline, s.c.) mice. Out of approximately 400 relevant genes in the arrays, 53 showed alterations in expression in cocaine-exposed fetuses. Upregulation was observed in 35 proapoptotic and 8 antiapoptotic genes; 4 proapoptotic and 6 antiapoptotic genes were down-regulated. The affected genes encode a wide range of apoptosis-related proteins, including death receptors (NTF-R1, NTF-R2, DR3, DR5, LTbeta-R, GITR, P57 TR-1) and their adaptor and regulatory proteins (MASGE-D1, TRAF-2, SIVA, MET, FLIP, FAIM, IAP1, ATFA), members of transcription regulatory pathways (JNK, NF-kappaB, P53), members of BCL-2 family of proteins (BID, BAD, BAX, BIK, NIP21, NIP3, NIX, BCL-2), DNA damage sensor (PARP-1), caspases and their substrates and regulatory proteins (caspases 8, 4, 9, and 3, ACINUS, CIDE-A, CIDE-B, GAS2), mitochondrially released factors (cytochrome c, AIF, PRG3), specific endoplasmic reticulum- and oxidative stress-associated factors (BACH2, ABL1, ALG2, CHOP), members of cell survival AKT and HSP70 pathways (PIK3GA, PTEN, HSP70, BAG1, BAG2), and others. This suggests that cocaine affects survival of developing cerebral cells via multiple apoptosis-regulating mechanisms. Experiment Overall Design: Animals Experiment Overall Design: Timed pregnant Swiss Webster (CFW; Charles River Experiment Overall Design: Lab. Wilmington, MA) dams were maintained in individual Experiment Overall Design: cages in a climate-controlled room on a 12/12-h light/ Experiment Overall Design: dark cycle. They were divided into two groups. The first Experiment Overall Design: (experimental) group received subcutaneous (at the dorsum Experiment Overall Design: of the neck) injections of 20 mg/kg cocaine hydrochloride Experiment Overall Design: (Research Technology Branch, National Institute Experiment Overall Design: of Drug Abuse, Rockville, MD) dissolved in 200 mkl of Experiment Overall Design: 0.9% saline, twice a day (at 8:00 AM and 8:00 PM) from Experiment Overall Design: 8th through 18th day of pregnancy (E8–E18). The second Experiment Overall Design: (control) group was subjected to the same schedule of Experiment Overall Design: 0.9% saline only injections. The cocaine treatment was Experiment Overall Design: designed to replicate the one capable of reducing cerebral Experiment Overall Design: cortical mass in mouse offspring. Also, the Experiment Overall Design: relatively protracted period the chronic treatment was Experiment Overall Design: chosen to maximize the changes in the tissue expression Experiment Overall Design: of cocaine-regulated genes of interest. Throughout the Experiment Overall Design: treatment, all mice were weighed daily, and, from E8, the Experiment Overall Design: control and experimental animals were pair-fed, with the Experiment Overall Design: daily amount of food (Mouse Chow; Ralston Purina Saint Experiment Overall Design: Louis, MO) provided to each control dam being matched Experiment Overall Design: to that consumed by the paired experimental dam. Water Experiment Overall Design: was available ad libitum. We found that this feeding Experiment Overall Design: regiment resulted in similar weight gains from E8 to E18 Experiment Overall Design: in both experimental and control animal groups Experiment Overall Design: (46.41F0.45% and 44.99F0.59% respectively). On E18, Experiment Overall Design: 1 h after the morning treatment, the animals were Experiment Overall Design: anesthetized by peritoneal injection of 50 mg/kg sodium Experiment Overall Design: pentobarbital (Abbott Lab., Abbott Park, IL) and their Experiment Overall Design: uteri were removed. The frontal cerebral wall (containing Experiment Overall Design: cerebral cortex and underlying transient cortical zones Experiment Overall Design: anterior to the striatal level) and the occipital cerebral wall Experiment Overall Design: (containing cerebral cortex and underlying transient Experiment Overall Design: cortical zones posterior to the level of the hippocampus) Experiment Overall Design: were dissected from the fetuses and stored in liquid Experiment Overall Design: nitrogen prior to analysis. The animal experimentations Experiment Overall Design: used in this study were approved by the University of Experiment Overall Design: Maryland Animal Care and Use Committee. Experiment Overall Design: Microarray Experiment Overall Design: Tissue from two control and two experimental fetuses Experiment Overall Design: were used in the processing of a single microarray slide Experiment Overall Design: (Part G4121A, Agilent Technol). Five slides were processed Experiment Overall Design: per region of the fetal cerebral wall. For a given region, the Experiment Overall Design: tissue for each microarray slide was obtained from a Experiment Overall Design: separate set of control and experimental litters. Total RNA Experiment Overall Design: was isolated using TRIzol Reagent (Invitrogen, Carlsbad, Experiment Overall Design: CA). The yield of total RNA was determined by absorbance Experiment Overall Design: at 260 nm on a DU 640 Spectrophotometer (Beckman Experiment Overall Design: Coulter, Fullerton, CA). The 260/280 nm ratios of the Experiment Overall Design: samples were >1.8. For each assay, 5 mkg of RNA from Experiment Overall Design: control tissue and 5 mkg of RNA from experimental tissue Experiment Overall Design: were reverse transcribed using 3DNA Array Detection Kit Experiment Overall Design: (Genesphere, Hatfield, PA) with primers containing different Experiment Overall Design: dcaptureT sequences for control and experimental Experiment Overall Design: samples. SuperScript II Reverse Transcriptase for these Experiment Overall Design: reactions was purchased from Gibco BRL (Gaithersburg, Experiment Overall Design: MD). The resultant cDNAs were hybridized to microarray Experiment Overall Design: slides for 16 h in Agilent Hybridization Buffer (Agilent Experiment Overall Design: Technol) at 60 8C. Upon completion of the hybridization, Experiment Overall Design: the slides were washed for 10 min with 0.005% Triton in Experiment Overall Design: 6xsodium chloride/sodium citrate buffer (pH 7; SSC) at Experiment Overall Design: room temperature and then for five more min with 0.005% Experiment Overall Design: Triton in 0.1xSSC and 1 more minute in 0.1xSSC (pH 7), Experiment Overall Design: both at 4 8C. Washed slides were air-dried for 30 s. For Experiment Overall Design: fluorescent labeling of microarray-bound cDNA, the slides Experiment Overall Design: were incubated for 3 h at 65 8C with Capture Reagent Experiment Overall Design: Hybridization Mixture from 3DNA Array Detection Kit Experiment Overall Design: (Genesphere). In this mixture, Alexa 546 fluorochromeincorporating Experiment Overall Design: dendrimers contained single-stranded arms Experiment Overall Design: complimentary to the dcaptureT sequences used in the Experiment Overall Design: reverse transcription of RNA from control tissue, while Experiment Overall Design: Alexa 647 fluorochrome-incorporating dendrimers contained Experiment Overall Design: arms complimentary to the capture sequences used Experiment Overall Design: in reverse transcription of RNA from experimental tissue. Experiment Overall Design: The labeling reaction was terminated by washing of the Experiment Overall Design: microarray slides at room temperature for 10 min with Experiment Overall Design: 0.005% Triton in 2xSSC and for another 10 min with in Experiment Overall Design: 0.2xSSC. After that, the slides were air-dried for 30 s. The Experiment Overall Design: processed microarray slides were scanned at 10 Am Experiment Overall Design: resolution on a GenePix 4100A scanner (Axon Instr., Union Experiment Overall Design: City, CA) with the laser excitation at 532 nm [emission filter Experiment Overall Design: 575DF35 (green); photomultiplier voltage 550] for Alexa Experiment Overall Design: 546 (control samples) and the laser excitation at 635 nm Experiment Overall Design: [emission filter 670DF40 (red); photomultiplier voltage Experiment Overall Design: 695] for Alexa 647 (experimental samples). The signals Experiment Overall Design: were converted into 16-bits-per pixel resolution images, Experiment Overall Design: providing color depth of 65,536 levels. The densitometry Experiment Overall Design: was performed with GenePix Pro 4.1 software (Axon Instr.). Experiment Overall Design: Background was subtracted using the dlocal background Experiment Overall Design: correctionT procedure available in the software. Quality control utilized 255 positive controls, 161 negative controls Experiment Overall Design: and 646 QC-spots present on Agilent’s arrays. For Experiment Overall Design: replicates within a slide, median signal values were Experiment Overall Design: calculated. For each array, the data were normalized in Experiment Overall Design: Acuity 3.1 software (Axon Instr.) by applying locally Experiment Overall Design: weighted scatterplot smoothing (LOWESS) transformation. Experiment Overall Design: The between array scale normalization Experiment Overall Design: was done using intensity log10 ratio distribution box plots (GeneSight Experiment Overall Design: software, BioDiscovery, El Segundo, CA) for verification. Experiment Overall Design: Statistical analysis of the normalized data was conducted Experiment Overall Design: by the Significant Analyses for Microarray Algorithm Experiment Overall Design: (SAM) using Excel macros available at the Stanford SAM website. Experiment Overall Design: In the analyses of both frontal and occipital regions of the fetal cerebral wall, Experiment Overall Design: the cut-off thresholds were set to identify the maximum Experiment Overall Design: number of cocaine exposure-regulated genes at the minimal Experiment Overall Design: false discovery rate (FDR) allowed by SAM for a given set Experiment Overall Design: of microarray data. For both regions, the FDR rates were Experiment Overall Design: <0.5%. The apoptosis and Wnt pathway-related genes were identified with Pathway Assist 2.0 software (Stratagene, La Jolla, CA). Experiment Overall Design: This was followed by manual review of literature for each Experiment Overall Design: identified gene.
Project description:While considerable progress has been made towards understanding the complex processes and pathways that regulate human wound healing, regenerative medicine has been unable to develop therapies that coax the natural wound environment to heal scar-free. The inability to induce perfect skin regeneration stems partly from our limited understanding of how scar-free healing occurs in a natural setting. Here we have investigated the wound repair process in adult axolotls and demonstrate that they are capable of perfectly repairing full thickness excisional wounds made on the flank. In the context of mammalian wound repair, our findings reveal a substantial reduction in hemostasis, reduced neutrophil infiltration and a relatively long delay in production of new extracellular matrix (ECM) during scar-free healing. Additionally, we test the hypothesis that metamorphosis leads to scarring and instead show that terrestrial axolotls also heal scar-free, albeit at a slower rate. Analysis of newly forming dermal ECM suggests that low levels of fibronectin and high levels of tenascin-C promote regeneration in lieu of scarring. Lastly, a genetic analysis during wound healing comparing epidermis between aquatic and terrestrial axolotls suggests that matrix metalloproteinases may regulate the fibrotic response. Our findings outline a blueprint to understand the cellular and molecular mechanisms coordinating scar-free healing that will be useful towards elucidating new regenerative therapies targeting fibrosis and wound repair. We used microarray analysis to determine the gene expression changes that take place during scar free wound healing in aquatic and terrestrial axolotl salamanders. Epidermal tissue was harvested using a 4mm biopsy punch. Two wounds were made along the flank and posterior to the forelimbs. Harvested epidermis was pooled for each animal. Four biological replicates were collected from uninjured epidermis (D0) and at 1, 3, and 7 days post injury.