Project description:CONTEXT Slowly progressive chronic tubulo-interstitial damage jeopardizes long-term renal allograft survival. Both immune and non-immune mechanisms are thought to contribute, but the most promising targets for timely intervention have not been identified. OBJECTIVE In the current study we seek to determine the driving force behind progressive histological damage of renal allografts, without the interference of donor pathology, delayed graft function and acute graft rejection. DESIGN We used microarrays to examine whole genome expression profiles in renal allograft protocol biopsies, and analyzed the correlation between gene expression and the histological appearance over time. The gene expression profiles in these protocol biopsies were then compared with gene expression of biopsies with acute T-cell mediated rejection. PATIENTS Human renal allograft biopsies (N=120) were included: 96 rejection-free protocol biopsies and 24 biopsies with T-cell mediated acute rejection. RESULTS In this highly cross-validated study, we demonstrate the significant association of established, ongoing and future chronic histological damage with regulation of adaptive immune gene expression (T-cell and B-cell transcript sets) and innate immune response gene expression (dendritic cell, NK-cell, mast cell and granulocyte transcripts). We demonstrate the ability of gene expression analysis to perform as a quantitative marker for ongoing inflammation with a wide dynamic range: from subtle subhistological inflammation prior to development of chronic damage, over moderate subclinical inflammation associated with chronic histological damage, to marked inflammation of Banff-grade acute T-cell mediated rejection. CONCLUSION Progressive chronic histological damage after kidney transplantation is associated with significant regulation of both innate and adaptive immune responses, months before the histological lesions appear. This study therefore corroborates the hypothesis that quantitative inflammation below the diagnostic threshold of classic T-cell or antibody-mediated rejection is associated with early subclinical stages of progressive renal allograft damage. We used microarrays to examine whole genome expression profiles in renal allograft protocol biopsies, and analyzed the correlation between gene expression and the histological appearance over time. The gene expression profiles in these protocol biopsies were then compared with gene expression of biopsies with acute T-cell mediated rejection. Human renal allograft biopsies (N=120) were included: 96 rejection-free protocol biopsies and 24 biopsies with T-cell mediated acute rejection.

Project description:Using array comparative genomic hybridization (aCGH), a large number of deleted genomic regions have been identified in human cancers. However, subsequent efforts to identify target genes selected for inactivation in these regions have often been challenging. We integrated here genome-wide copy number data with gene expression data and non-sense mediated mRNA decay rates in breast cancer cell lines to prioritize gene candidates that are likely to be tumour suppressor genes inactivated by bi-allelic genetic events. The candidates were sequenced to identify potential mutations. This integrated genomic approach led to the identification of RIC8A at 11p15 as a putative candidate target gene for the genomic deletion in the ZR-75-1 breast cancer cell line. We identified a truncating mutation in this cell line, leading to loss of expression and rapid decay of the transcript. We screened 127 breast cancers for RIC8A mutations, but did not find any pathogenic mutations. No promoter hypermethylation in these tumours was detected either. However, analysis of gene expression data from breast tumours identified a small group of aggressive tumours that displayed low levels of RIC8A transcripts. Real-time PCR analysis of 38 breast tumours showed a strong association between low RIC8A expression and the presence of TP53 mutations (P=0.006). We demonstrate a data integration strategy leading to the identification of RIC8A as a gene undergoing a classical double-hit genetic inactivation in a breast cancer cell line, as well as in vivo evidence of loss of RIC8A expression in a subgroup of aggressive TP53 mutant breast cancers. Gene expression data: Samples GSM388181-GSM388198. The experiment utilized six breast cancer cell lines: MDA-MB-468, MDA-MB-231, ZR-75-1, MCF7, BT-474 and T-47D, and three non-malignant cell lines: HMECs (non-malignant human mammary epithelial cells), IMR90 (normal lung fibroblasts) and WS1 (normal skin fibroblasts). All cell lines were obtained from American Type Culture Collection and grown in accordance with the distributor's instructions. Both malignant and non-malignant cell lines were treated with the translation inhibitor emetine dihydrochloride hydrate. For each cell line, parallel cell cultures were grown in 175 cm2 flasks until 70-80 % confluence. Half of the subconfluent cultures were treated with 100 Î¼g ml-1 of emetine dihydrochloride hydrate while the other half were left as untreated controls. Genome-wide copy number data: Samples GSM388211-GSM388216. The experiment utilized six breast cancer cell lines; MDA-MB-468, MDA-MB-231, ZR-75-1, MCF7, BT-474 and T-47D. All cell lines were obtained from American Type Culture Collection and grown in accordance with the distributor's instructions. All samples were hybridized once on 44k Agilent Human Genome CGH microarrays according to manufacturers instructions. Genomic DNA pooled from healthy female donors was used as a reference in all hybridizations. DNA from cell line samples were labeled with Cy5 and DNA from reference were labeled with Cy3.

Project description:The lower glucose-responsiveness of neonatal beta cells is generally considered a sign of endocrine immaturity. We compared mRNA profiles of neonatal and 10-weeks old rat beta cells to see how their gene expression changes with functional maturation. Neonatal beta cells showed a lower glucose-inducible increment in insulin production than adult cells. This was in part explained by basal protein synthetic hyperactivity of neonatal cells: while at 2.5mM glucose 80% of neonatal beta cells were recruited into active protein synthesis, 10 mM glucose was required to achieve a similar fraction of active adult beta cells. Besides this progressive recruitment, glucose exerted in both age groups an additional amplifying effect in the recruited cells, but clearly more so in adult beta cells that showed a higher maximal synthetic capacity/cell. Neonatal beta cells balanced an advanced endocrine differentiation as judged by their mRNA expression of conserved beta cell marker genes, with higher expression of genes involved in cell cycle and development. One example, Delta-like 1 homolog (DLK1) was used to investigate if neonatal beta cells with basal hyperactivity corresponded to a more immature subset, as marked by high DLK1. Neonatal pancreas contained distinct subsets of DLK1high and DLK1low insulin-expressing cells, but both showed equal hyperactivity. We conclude that neonatal beta cells combine advanced endocrine maturation with traits of residual developmental immaturity. If DLK1 is used as marker for the latter, the basal hyperactivity which proved to be a cardinal feature of neonatal beta cells is not a direct reflection of their residual immaturity. A genome-wide view on postnatal maturation/differentiation of the rat beta cells The study compares Affymetrix RG230.20 expression profiles of 3 cell subsets: (1) HSSC: a population of cells isolated from post natal day 2-3 rat pancreas that is enriched (65-70%) in insulin cells (n=3), (2) LSSC: a population of cells isolated from postnatal day 2-3 rat pancreas that is mostly devoid of endocrine cells, and selected by its low side scatter (n=3); and (3) adult beta: a reference population of FACS-purified adult rat beta cells (>90% insulin+) freshly isolated from pancreas of 10 weeks-old rats (n=5). RNA was extracted from the cells immediately after isolation, without further treatment or culture. Details of the isolation procedure and extensive microscopic characterization of the preps are described in the accompanying scientific paper by Martens GA et al.

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Pacreatic Cell Line Transcriptomics

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