Project description:Experiment description 1. Experimental design 1) Authors, laboratory, and contact: Xue-Lin Cui1, Patricia Soteropoulos2, Peter Tolias2, Ronaldo P. Ferraris1: 1Dept. of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, NJ 07103-2714, 2Center for Applied Genomics, PHRI, 225 Warren Street Newark, NJ 07103-3506. Contact to Dr. Ronaldo P. Ferraris. 2) Type of the experiment: treated vs. untreated comparison. 3) Experimental factors: Twenty to twenty-two old SD rats were use in the experiment. The intestines of paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h or 20-min, respectively. 4) Totally 14 experiments were done. 5) A common reference was not used for all the hybridizations. 6) Quality control steps ( 14) Miller RA, Galecki A, Shmookler-Reis RJ. Interpretation, design, and analysis of gene array expression experiments. J Gerontol A Biol Sci Med Sci. 2001 Feb;56(2):B52-7. (15) Tseng GC, Oh MK, Rohlin L, Liao JC, Wong WH. Issues in cDNA microarray analysis: quality filtering, channel normalization, models of variations and assessment of gene effects. Nucleic Acids Res. 2001 Jun 15;29(12):2549-57. ( 16) Yang YH, Speed T. Design issues for cDNA microarray experiments. Nat Rev Genet. 2002 Aug;3(8):579-88. (17) Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.): a) In the 4 h perfusion experiment, the intestines of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h, respectively. Totally five replicates were conducted. The RNA samples were extracted from HF- and HG-perfused intestines (n=5 pairs) then labelled with Cy 5 (HF1, HF2, HF3, HF4, and HF5) and Cy 3 (HG1, HG2, HG3, HG4, and HG5), respectively. At the same time, one dye swap experiment, in which the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF1) and Cy 5 (HG1), respectively, was done and used in the data analysis. b) In the 20 min perfusion experiment, the intestines of of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 20-min, respectively. Totally four replicates were conducted. In two of the four-replicate experiments, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 5 (HF1a and HF3a) and Cy 3 (HG1a and HG3a), respectively. In the other two of the four-replicate experiments, the dye was swapped, that is, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF2a and HF4a) and Cy 5 (HG2a and HG4a), respectively. c) Three self-self experiments using different samples (HF1, HG1, and HF2) and one capture primer alone experiment were conducted to eliminate the false positive genes and aid to analyze the data. 7) The goal of the experiment: Fructose induced the expression of GLUT5 mRNA in the small intestinal epithelial cells. But it is not clear about the mechanisms involved in the phenomenal. In this experiment, we hypothesize: the expression of some genes must be changed after fructose perfusion for 4-h, these genes may regulate GLUT5 gene transcription; the expression of some genes must be changed even after 20-min fructose perfusion, these genes may trigger the GLUT5 gene expression as early response gene. Our goal in this study is to find out these potencial gene. 8) Links (URL), citations 2. Samples used, extract preparation, labeling and hybridization 1) Bio-source properties a) Sprague Dawley rats (NCBI taxonomy); b) The rat was anesthetized using urathene. The rat body was kept at 37 oC under light. c) Descriptors relevant to the particular sample: the jejunum of the 20-d old rat pups (unknown sex) was perused. 2) Biomaterial manipulations: the jejunum was in vivo perfused with 100 mM HF or HG for 4-h or 20-min. At the end of each experiment, the jejunum was immediately cut out and snap frozen in liqued nitrogen, and then stored the tissue in -80 oC freezer. 3) RNA isolation: A RNeasy Midi Kit (QIAGEN Inc., Valencia, CA) was used to extract total RNA from the jejunum. The brief procesure is described in the Total RNA Extraction for RT-PCR and Microarray above. 4) Sample assignment to slides for labeling and hybridization: S1: HF1(Cy 5) vs HG1 (Cy 3); S2: HF2 (Cy 5) vs HG2 (Cy 3); S3: HF3 (Cy 5) vs HG3 (Cy 3); S4: HF4 (Cy 5) vs HG4 (Cy 3); S5: HF5 (Cy 5) vs HG5 (Cy 3); S6: HF2 (Cy 3) vs HG2 (Cy 5); S7: HF1a (Cy 5) vs HG1a (Cy 3); S8: HF3a (Cy 5) vs HG3a (Cy 3); S9: HF2a (Cy 3) vs HG2a (Cy 5); S10: HF4a (Cy 3) vs HG4a (Cy 5); S11: HG1 (Cy 5) vs HG1 (Cy 3); S12: HG3 (Cy 5) vs HG3 (Cy 3); S13: HF3 (Cy 5) vs HF3 (Cy 3); S14: Cy 3 vs Cy 5 capture primer. 5) Labeling and hybridization procedures and parameters: The 3DNA Submicro Oligo Expression Array Detection Kit (Genisphere Inc., Hatfield, PA) was employed to synthesize and label the complimentary DNA (cDNA) with fluorescent dye: Cy3 or Cy5. The reason why this indirect labeling method was chosen is based on a previous study which demonstrated that the method was more sensitive and consistent than direct labeling method or other indirect techniques like aminoallyl labeling method and MICROMAX tyramide signal amplification labeling method. (18)Yu J, Othman MI, Farjo R, et al: Molecular Vision 2002; 8:130-137). In the primary experiments, three, four, and five g of total RNA were tested for labeling and hybridization conditions. In the official experiments, four g of total RNA isolated from each sample were used for labeling and hybridization, because the signal to noise ratio is high at this concentration. In addition, at this concentration, all most of the low expressed genes are detectable and the highly expressed genes are not fully saturated. The procedure was conducted following the manufacturer's protocol. Briefly, the first strand cDNA was synthesized using a specific poly T Cy3 RT primer or a specific poly T Cy5 RT primer in different tubes for paired samples. Combine the Cy3 and Cy5 reactions in one tube and precipitate the sample in ethanol. After briefly drying the pellet, resuspend the pellet with 40 l of hybridization buffer. Subsequently, apply the hybridization mixture onto the array slide and hybridize overnight at 55 oC in a humidified chamber. Following the hybridization, the slides were washed by placing them into 50 ml conical tubes containing 2 x SSC, 0.2% SDS for 15 min, 2 x SSC for 10 min, 0.2 x SSC for 10 min, and 95% ethanol for 1 min all at room temperature, except for the first wash, in which the temperature was 42 oC. After drying the slides, the Cy3 and Cy5 capture (connected to dye molecues) reagents mixed in hybridization buffer was pipeted onto the slides, and then hybridize at 65 oC for 3 h following slides wash as described above. 3. Measurement data and spesifications of data processing 1) Raw data description Slides were scanned for Cy3 and Cy5 fluorescence using an Axon GenePix4000 microarray reader (GenePix 4000A, Axon instruments, Foster City, CA) and quantitated using GenePix software. Scan parameters: Scan power: Cy 3 : Cy 5 = 100:100; Laser power: Cy 3 : Cy 5 = 1.15:1.76; Spatial resolution: ???; Pixel size: 10 or 100 ???; Pixel number: F pixels: 50-100; B pixels: 400-500 ???; PMT voltage: 600-750 for Cy 5 channel, 650-850 for Cy 3 channel. 2) Image analysis and quantitation For the image analysis, the density of the spots was detected using Gene Spring (Silicon Genetics, Redwood City, CA) software (GeniPix 4.0) (19) Axon Instruments Inc. (1999) GenePix 4000A User's Guide. Axon Instruments, Union City, CA). It is commercially available. Description of the algorithm and all the parameters used: R = red channel signal = F635; G = green channel signal = B 532; M = log2(R/G); A = 1/2xlog2(RxG); User-difined parameter f = 40%. For the complete image analysis out put of each image, see the NCBI's GEO database (www.ncbi.nlm.nih.gov/geo). 3) Normalized and summarized data-gene expression data matrix For the normalization, the following two steps were taken. a) When measuring the density of the spots using Gene Spring software, the ratio of Cy 3 and Cy 5 dyes was adjusted as 1 as a globle normalization for the whole slide. b) For the gene expression analysis, the results (midian of the density of the pixel in one spot was used) were normalized by a LOWESS (locally weighed scatter smoother) software provided by the Center for Applied Genomics, so that the results can be compared among the experiments performed at different times. (20)Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.). c) The following rules were made to decide the genes that were significantly changed: 1) Eliminate the genes with high density (over than 2X of background) in the 3DNA capture probe experiments; 2) Eliminate the genes with density lower than 2X of background ( 21) Lee HM, Greeley GH Jr, Englander EW. Age-associated changes in gene expression patterns in the duodenum and colon of rats. Mech Ageing Dev. 2001 Apr 15;122(4):355-71.); 3) Eliminate the genes with change over than 1.5X in dye flip-over experiment; 4) Eliminate the genes with opposite results in one experiments between dye flip-over comparisons; 5) Only the genes significantly changed over 3 in 5 comparisons in 4 h perfusion experiment and over 2 in 4 comparisons in 20 min perfusion experiment were considered as reliable and biologically important. d) The final results discribed in this paper were presented as Means + SE and the frequency of gene changed in the HF-perfused intestine. About the image, raw, and normalized data, and other detailed parameters, please see the gene expression data tables derived from the experiments in the NCBI's GEO database. The design for the dye labeling in this experiments is as the follows: 1) 5 comparisons were conducted in the 4 h-perfused HG vs HF experiment, in which in 3 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 2) 4 comparisons were conducted in the 20 min-perfused HG vs HF experiment, in which in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 3) 3 dye flip-over experiments using 1 RNA sample extracted from HF-perfused intestine and 2 samples extracted from HG-perfused intestines were performed to eliminate the false positive results induced by the dye labeling technique or other unsolved problems. 4) 2 experiments only applying 3DNA fluorescent probe, which is connected to complementary capture sequence, were performed to eliminate the false positive genes that were low expressed in the tissue. The procedures for synthesizing the first strand cDNA, labeling the cDNA, hybridizaion, and detecting the signals were performed following the manufacturer's protocols. Keywords: other

Project description:TREM2 is a microglial cell surface receptor, with risk mutations linked to Alzheimer’s disease (AD), including R47H. TREM2 signalling via SYK aids phagocytosis, chemotaxis, survival, and changes to microglial activation state. In AD mouse models, knockout (KO) of TREM2 impairs microglial clustering around amyloid, and prevents microglial activation. The R47H mutation is proposed to reduce TREM2 ligand binding. We investigated cell phenotypes of the R47H mutant and TREM2 KO in a model of human microglia, and compared their transcriptional signatures, to determine the mechanism by which R47H TREM2 disrupts function. We generated human microglia-like iPSC-macrophages (pMac) from isogenic induced pluripotent stem cell (iPSC) lines, with homozygous R47H mutation or TREM2 knockout (KO). We firstly validated the effect of the R47H mutant on TREM2 surface and subcellular localization in pMac. To assess microglial phenotypic function we measured phagocytosis of dead neurons, cell morphology, directed migration, survival, and LPS-induced inflammation. We performed bulk RNA-seq, comparing significant differentially-expressed genes (DEGs: p<0.05) between the R47H and KO versus WT, and bioinformatically predicted potential upstream regulators of TREM2-mediated gene expression. Altered gene expression in the R47H TREM2 pMac overlapped by 90% with the TREM2 KO, and was characterized by dysregulation of genes involved with immunity, proliferation, activation, chemotaxis and adhesion. Downregulated mediators of ECM adhesion included the vitronectin receptor αVβ3, and consequently R47H TREM2 pMac adhered weakly to vitronectin compared with WT pMac. To counteract these transcriptional defects, we investigated TGFβ1, as a candidate upstream regulator. TGFβ1 failed to rescue vitronectin adhesion of pMac, although improved αVβ3 expression. The R47H mutation is not sufficient to cause gross phenotypic defects of human pMac under standard culture conditions. However, overlapping transcriptional defects with TREM2 KO supports the hypothesised partial loss-of-function effects of the R47H mutation. Furthermore, transcriptomics can guide us to more subtle phenotypic defects in the R47H cells, such as reduced cell adhesion, and can be used to predict targets for therapeutic intervention.

Project description:Unravel the mechanisms underlying brain aging and Alzheimer´s disease (AD) has been difficult because of complexity of the networks that drive these aging-related changes. Analysis of the gene expression in the brain is a valuable tool to study the function of the brain under normal and pathological conditions. Gene microarray technology allows massively parallel analysis of most genes expressed in a tissue, and therefore is an important research tool that potentially can provide the investigative power needed to address the complexity of brain aging and neurodegenerative processes. One of the reasons that account for the resistance of AD pathogenesis to analysis is that clinically normal subjects may exhibit considerable AD pathology, blurring criteria for distinguishing subjects with normal aging or AD. Here, we analyzed hippocampal and cortex frontal gene expression from 32 subjects separated in individuals presenting, 1) both pathologic and clinical AD (definitive AD); 2) AD pathology and normal clinic (pathologic AD); 3) cognitive impairment, without AD pathology (others dementias); and 4) no cognitive impairment, without AD pathology (normal individuals). Our results show that based on gene expression profile these individuals we could verify similarity between the definitive AD group and the group that only had AD-type pathology (pathologic AD). Specimens of hippocampus and cortex frontal used in this study were obtained at autopsy from 32 subjects. Neuropathology, specifically NFT and NP, was assessed in accordance to the Braak staging and CERAD scores, respectively. Based on pathologic and clinic criteria, subjects were categorized into four groups: 1) nine subjects with AD neuropathologic (Braak = IV / V / VI and CERAD ≠ 0) presenting cognitive impairment (CDR ≥ 1), termed “definitive AD” (dAD); 2) five subjects with AD neuropathologic (Braak = IV / V / VI and CERAD ≠ 0) and without cognitive impairment (CDR = 0), termed “pathologic AD” (pAD); 3) nine subjects without AD neuropathologic (Braak = 0 / I / II and CERAD ≠ C) presenting cognitive impairment (CDR ≥ 1), termed “other dementias” (OD); 4) - nine subjects without AD neuropathologic (Braak = 0 / I / II and CERAD ≠ C) and without cognitive impairment (CDR = 0), termed “normal” (N). RNA isolation and Amplification. From total RNA, a two-round linear amplification procedure (T7-based protocol) was carried out for all samples and for a pool of RNAs obtained from 15 distinct human cell lines used as reference. Labeled cDNA was generated in a reverse transcriptase reaction using amplified RNA (aRNA). Equal amounts of test and reference cDNA reverse color Cy-labeled aRNA targets were competitively hybridized against the cDNA probes in a customized cDNA platform with 4,608 ORESTES representing human genes. Dye-swap was performed for each sample as control for dye bias and used as replicate.

Project description:Experiment description 1. Experimental design 1) Authors, laboratory, and contact: Xue-Lin Cui1, Patricia Soteropoulos2, Peter Tolias2, Ronaldo P. Ferraris1: 1Dept. of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, NJ 07103-2714, 2Center for Applied Genomics, PHRI, 225 Warren Street Newark, NJ 07103-3506. Contact to Dr. Ronaldo P. Ferraris. 2) Type of the experiment: treated vs. untreated comparison. 3) Experimental factors: Twenty to twenty-two old SD rats were use in the experiment. The intestines of paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h or 20-min, respectively. 4) Totally 14 experiments were done. 5) A common reference was not used for all the hybridizations. 6) Quality control steps ( 14) Miller RA, Galecki A, Shmookler-Reis RJ. Interpretation, design, and analysis of gene array expression experiments. J Gerontol A Biol Sci Med Sci. 2001 Feb;56(2):B52-7. (15) Tseng GC, Oh MK, Rohlin L, Liao JC, Wong WH. Issues in cDNA microarray analysis: quality filtering, channel normalization, models of variations and assessment of gene effects. Nucleic Acids Res. 2001 Jun 15;29(12):2549-57. ( 16) Yang YH, Speed T. Design issues for cDNA microarray experiments. Nat Rev Genet. 2002 Aug;3(8):579-88. (17) Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.): a) In the 4 h perfusion experiment, the intestines of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h, respectively. Totally five replicates were conducted. The RNA samples were extracted from HF- and HG-perfused intestines (n=5 pairs) then labelled with Cy 5 (HF1, HF2, HF3, HF4, and HF5) and Cy 3 (HG1, HG2, HG3, HG4, and HG5), respectively. At the same time, one dye swap experiment, in which the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF1) and Cy 5 (HG1), respectively, was done and used in the data analysis. b) In the 20 min perfusion experiment, the intestines of of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 20-min, respectively. Totally four replicates were conducted. In two of the four-replicate experiments, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 5 (HF1a and HF3a) and Cy 3 (HG1a and HG3a), respectively. In the other two of the four-replicate experiments, the dye was swapped, that is, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF2a and HF4a) and Cy 5 (HG2a and HG4a), respectively. c) Three self-self experiments using different samples (HF1, HG1, and HF2) and one capture primer alone experiment were conducted to eliminate the false positive genes and aid to analyze the data. 7) The goal of the experiment: Fructose induced the expression of GLUT5 mRNA in the small intestinal epithelial cells. But it is not clear about the mechanisms involved in the phenomenal. In this experiment, we hypothesize: the expression of some genes must be changed after fructose perfusion for 4-h, these genes may regulate GLUT5 gene transcription; the expression of some genes must be changed even after 20-min fructose perfusion, these genes may trigger the GLUT5 gene expression as early response gene. Our goal in this study is to find out these potencial gene. 8) Links (URL), citations 2. Samples used, extract preparation, labeling and hybridization 1) Bio-source properties a) Sprague Dawley rats (NCBI taxonomy); b) The rat was anesthetized using urathene. The rat body was kept at 37 oC under light. c) Descriptors relevant to the particular sample: the jejunum of the 20-d old rat pups (unknown sex) was perused. 2) Biomaterial manipulations: the jejunum was in vivo perfused with 100 mM HF or HG for 4-h or 20-min. At the end of each experiment, the jejunum was immediately cut out and snap frozen in liqued nitrogen, and then stored the tissue in -80 oC freezer. 3) RNA isolation: A RNeasy Midi Kit (QIAGEN Inc., Valencia, CA) was used to extract total RNA from the jejunum. The brief procesure is described in the Total RNA Extraction for RT-PCR and Microarray above. 4) Sample assignment to slides for labeling and hybridization: S1: HF1(Cy 5) vs HG1 (Cy 3); S2: HF2 (Cy 5) vs HG2 (Cy 3); S3: HF3 (Cy 5) vs HG3 (Cy 3); S4: HF4 (Cy 5) vs HG4 (Cy 3); S5: HF5 (Cy 5) vs HG5 (Cy 3); S6: HF2 (Cy 3) vs HG2 (Cy 5); S7: HF1a (Cy 5) vs HG1a (Cy 3); S8: HF3a (Cy 5) vs HG3a (Cy 3); S9: HF2a (Cy 3) vs HG2a (Cy 5); S10: HF4a (Cy 3) vs HG4a (Cy 5); S11: HG1 (Cy 5) vs HG1 (Cy 3); S12: HG3 (Cy 5) vs HG3 (Cy 3); S13: HF3 (Cy 5) vs HF3 (Cy 3); S14: Cy 3 vs Cy 5 capture primer. 5) Labeling and hybridization procedures and parameters: The 3DNA Submicro Oligo Expression Array Detection Kit (Genisphere Inc., Hatfield, PA) was employed to synthesize and label the complimentary DNA (cDNA) with fluorescent dye: Cy3 or Cy5. The reason why this indirect labeling method was chosen is based on a previous study which demonstrated that the method was more sensitive and consistent than direct labeling method or other indirect techniques like aminoallyl labeling method and MICROMAX tyramide signal amplification labeling method. (18)Yu J, Othman MI, Farjo R, et al: Molecular Vision 2002; 8:130-137). In the primary experiments, three, four, and five g of total RNA were tested for labeling and hybridization conditions. In the official experiments, four g of total RNA isolated from each sample were used for labeling and hybridization, because the signal to noise ratio is high at this concentration. In addition, at this concentration, all most of the low expressed genes are detectable and the highly expressed genes are not fully saturated. The procedure was conducted following the manufacturer's protocol. Briefly, the first strand cDNA was synthesized using a specific poly T Cy3 RT primer or a specific poly T Cy5 RT primer in different tubes for paired samples. Combine the Cy3 and Cy5 reactions in one tube and precipitate the sample in ethanol. After briefly drying the pellet, resuspend the pellet with 40 l of hybridization buffer. Subsequently, apply the hybridization mixture onto the array slide and hybridize overnight at 55 oC in a humidified chamber. Following the hybridization, the slides were washed by placing them into 50 ml conical tubes containing 2 x SSC, 0.2% SDS for 15 min, 2 x SSC for 10 min, 0.2 x SSC for 10 min, and 95% ethanol for 1 min all at room temperature, except for the first wash, in which the temperature was 42 oC. After drying the slides, the Cy3 and Cy5 capture (connected to dye molecues) reagents mixed in hybridization buffer was pipeted onto the slides, and then hybridize at 65 oC for 3 h following slides wash as described above. 3. Measurement data and spesifications of data processing 1) Raw data description Slides were scanned for Cy3 and Cy5 fluorescence using an Axon GenePix4000 microarray reader (GenePix 4000A, Axon instruments, Foster City, CA) and quantitated using GenePix software. Scan parameters: Scan power: Cy 3 : Cy 5 = 100:100; Laser power: Cy 3 : Cy 5 = 1.15:1.76; Spatial resolution: ???; Pixel size: 10 or 100 ???; Pixel number: F pixels: 50-100; B pixels: 400-500 ???; PMT voltage: 600-750 for Cy 5 channel, 650-850 for Cy 3 channel. 2) Image analysis and quantitation For the image analysis, the density of the spots was detected using Gene Spring (Silicon Genetics, Redwood City, CA) software (GeniPix 4.0) (19) Axon Instruments Inc. (1999) GenePix 4000A User's Guide. Axon Instruments, Union City, CA). It is commercially available. Description of the algorithm and all the parameters used: R = red channel signal = F635; G = green channel signal = B 532; M = log2(R/G); A = 1/2xlog2(RxG); User-difined parameter f = 40%. For the complete image analysis out put of each image, see the NCBI's GEO database (www.ncbi.nlm.nih.gov/geo). 3) Normalized and summarized data-gene expression data matrix For the normalization, the following two steps were taken. a) When measuring the density of the spots using Gene Spring software, the ratio of Cy 3 and Cy 5 dyes was adjusted as 1 as a globle normalization for the whole slide. b) For the gene expression analysis, the results (midian of the density of the pixel in one spot was used) were normalized by a LOWESS (locally weighed scatter smoother) software provided by the Center for Applied Genomics, so that the results can be compared among the experiments performed at different times. (20)Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.). c) The following rules were made to decide the genes that were significantly changed: 1) Eliminate the genes with high density (over than 2X of background) in the 3DNA capture probe experiments; 2) Eliminate the genes with density lower than 2X of background ( 21) Lee HM, Greeley GH Jr, Englander EW. Age-associated changes in gene expression patterns in the duodenum and colon of rats. Mech Ageing Dev. 2001 Apr 15;122(4):355-71.); 3) Eliminate the genes with change over than 1.5X in dye flip-over experiment; 4) Eliminate the genes with opposite results in one experiments between dye flip-over comparisons; 5) Only the genes significantly changed over 3 in 5 comparisons in 4 h perfusion experiment and over 2 in 4 comparisons in 20 min perfusion experiment were considered as reliable and biologically important. d) The final results discribed in this paper were presented as Means + SE and the frequency of gene changed in the HF-perfused intestine. About the image, raw, and normalized data, and other detailed parameters, please see the gene expression data tables derived from the experiments in the NCBI's GEO database. The design for the dye labeling in this experiments is as the follows: 1) 5 comparisons were conducted in the 4 h-perfused HG vs HF experiment, in which in 3 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 2) 4 comparisons were conducted in the 20 min-perfused HG vs HF experiment, in which in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 3) 3 dye flip-over experiments using 1 RNA sample extracted from HF-perfused intestine and 2 samples extracted from HG-perfused intestines were performed to eliminate the false positive results induced by the dye labeling technique or other unsolved problems. 4) 2 experiments only applying 3DNA fluorescent probe, which is connected to complementary capture sequence, were performed to eliminate the false positive genes that were low expressed in the tissue. The procedures for synthesizing the first strand cDNA, labeling the cDNA, hybridizaion, and detecting the signals were performed following the manufacturer's protocols.

Project description:Wilms tumor (WT), the commonest renal tumor of the childhood, is originated from pluripotent metanephric blastemal cells resulting in tumors with triphasic histology, composed by blastemal, epithelial, and stromal cells. Histological subtype and tumor stage have long been recognized as important prognostic factors and used for the current therapeutic approach with blastema considered as the component with the highest clinical impact. Current clinical and molecular research is directed toward identifying prognostic factors for both purposes, definition of the minimal or intense required therapy for successful treatment of children with low or high risk of relapse, respectively. In this study, to identify molecular prognostic markers predictive of tumor relapse, samples from 26 advanced (Stage III or IV) blastemal WT, whose patients presented (13 samples) or did not present (13 samples) relapse, were interrogated by 4,608 human genes immobilized in a customized cDNA platform. This analysis revealed a set of 69 differentially expressed genes, where the nine top genes were evaluated by qRT-PCR in the initial WT samples. TSPAN3, NCOA6, CDO1, MPP2 and MCM2 were technically confirmed showing down-regulation in relapse WT. TSPAN3 and NCOA6 were validated in an independent sample group. Gene trios containing these two genes combined with one of the remaining three reported a reasonable capability of discriminating relapse and no-relapse WT. Negative protein expression of MCM2 and NCOA6 was observed in around 62% and 72% of 34 independent stage III and IV WT patients, respectively without association with relapse. However, a significant association between MCM2 negative staining and chemotherapy as first treatment was observed suggesting that MCM2 protein expression is implicated anyhow with chemotherapy treatment in WT. Twenty-six blastemal-enriched advanced stage (III or IV) WT samples from sporadic and favorable histology WT were received from Children Oncology Group (COG) and used were used for microarray experiments, from which 13 samples were from patients without relapse in 5 years of follow up. Tumors were taken from primary nephrectomy at the time of initial diagnosis. Blastemal histological component was isolated following protocol described in Maschietto et al. (2008). Only samples with >80% of blastemal cells were used. Total RNA was isolated using TRIzol (Sigma) according to manufacturer´s instructions. RNA quantity and integrity was assessed by spectrophotometry (Nanodrop) and microfluidics-based electrophoresis (Agilent 2100 Bioanalyzer, Agilent), respectively, selecting only RNA samples with OD around 2.0 and RIN>5.0. A two-round RNA amplification procedure (Gomes et al. 2003) was carried out for all samples. Labeled cDNA was generated in a reverse transcriptase reaction using 4 ug of amplified RNA (aRNA), random hexamer primer (Invitrogen Life Technologies, Carlsbad, CA), Alexa-3 or 5-labeled dCTP (Amersham, Biosciences) and IMPROM (PROMEGA) using oligo-dT7(24), following manufacture recommendations. Five µg of test and reference cDNA reverse color Alexa-labeled aRNA targets were competitively hybridized against the cDNA probes in a customized cDNA platform with 4,608 ORESTES representing human genes. Dye-swap was performed for each sample as control for dye bias and used as replicate. Pre-hybridization and hybridization were performed as described (Maschietto et al. 2008). A pool of RNAs obtained from 15 distinct human cell lines as was used as reference. Signal intensities capture and analysis were performed as described in Maschietto et al (2008).

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Human tumor cell lines treated with 5AZA-dC vs control untreated cells.

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