| 1. |
- Byrnes, Andrea, et al.
(författare)
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Gene expression in peripheral blood leukocytes in monozygotic twins discordant for chronic fatigue : no evidence of a biomarker
- 2009
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 4:6, s. e5805-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chronic fatiguing illness remains a poorly understood syndrome of unknown pathogenesis. We attempted to identify biomarkers for chronic fatiguing illness using microarrays to query the transcriptome in peripheral blood leukocytes. METHODS: Cases were 44 individuals who were clinically evaluated and found to meet standard international criteria for chronic fatigue syndrome or idiopathic chronic fatigue, and controls were their monozygotic co-twins who were clinically evaluated and never had even one month of impairing fatigue. Biological sampling conditions were standardized and RNA stabilizing media were used. These methodological features provide rigorous control for bias resulting from case-control mismatched ancestry and experimental error. Individual gene expression profiles were assessed using Affymetrix Human Genome U133 Plus 2.0 arrays. FINDINGS: There were no significant differences in gene expression for any transcript. CONCLUSIONS: Contrary to our expectations, we were unable to identify a biomarker for chronic fatiguing illness in the transcriptome of peripheral blood leukocytes suggesting that positive findings in prior studies may have resulted from experimental bias.
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| 2. |
- Gräns, Hanna, et al.
(författare)
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Reduced levels of oestrogen receptor beta mRNA in Swedish patients with chronic fatigue syndrome.
- 2007
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Ingår i: Journal of Clinical Pathology. - : BMJ. - 0021-9746 .- 1472-4146. ; 60:2, s. 195-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chronic fatigue syndrome (CFS) is an illness with unknown aetiology and pathophysiology. The difference in incidence by sex observed for CFS indicates a role for oestrogen and oestrogen receptors in disease development. Furthermore, an immunomediated pathogenesis has been suggested for CFS, providing an additional connection to oestrogen, which displays immunomodular functions. AIMS: To investigate a possible association of oestrogen receptor (ER) mRNAs and two ERbeta single-nucleotide polymorphisms (SNPs) with CFS. METHODS: Messenger RNA levels of ERalpha, ERbeta wt and ERbeta cx were investigated in peripheral blood mononuclear cells from 30 patients with CFS and 36 healthy controls by quantitative real-time polymerase chain reaction. Two ERbeta SNPs were scored in the same material. RESULTS: The CFS group showed significantly lower mRNA expression levels of ERbeta wt compared with the healthy control group. No differences were observed for ERalpha or ERbeta cx between patients and controls. There were no significant differences in frequency for the investigated ERbeta SNPs between cases and controls. CONCLUSIONS: The reduced ERbeta wt expression level observed in this study is consistent with an immune-mediated pathogenesis of CFS. Additionally, the observation that ERbeta wt expression is decreased in CFS could provide an entry point to identify interesting, potentially disease-causing, candidate molecules for further study. A possible connection between oestrogen, oestrogen receptors and CFS should be evaluated further.
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| 3. |
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| 4. |
- Laurell, Cecilia, 1977-
(författare)
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Microarray Based Gene Expression Analysis in Cancer Research
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biotechnological inventions during the 20th century have resulted in a wide range of approaches for explorations in the functional genomics field. Microarray technology is one of the recent advances which have provided us with snapshots of which genes are expressed in cells of various tissues and diseases. Methods to obtain reliable microarray data are continuously being developed and improved to meet the demands of biological researchers.In this thesis microarrays have been used to investigate gene expression patterns in cancer research. Four studies in three different areas were carried out covering adrenocortical tumors, p53 target genes and a comparison of RNA amplification methods.Adrenocortical tumours are among the most common tumours with an incidence of 7-9%. Malignancy of these tumors is rare. Distinction between malignant and benign tumours is often difficult to establish which makes an improvement of diagnostic approaches important. To elucidate biological processes in adrenocortical tumour development and to examine if there is a molecular signature associated with malignancy, microarray analysis was performed on 29 adrenocortical tumors and four normal specimens. It was possible to classify malignant and benign samples based on the entire expression profile. A number of potential biomarkers was identified which will be further evaluated.P53 is a gene which is mutated in 50% of all cancers. Functional p53 is a transcription factor which is activated upon cellular stress and DNA damage. Target genes are mainly involved in cell cycle arrest and apoptosis. In solid tumors cells are stressed by hypoxia. To examine which target genes p53 activate under hypoxic conditions a microarray study of the cell lines HCT116p53+/+ and HCT116p53-/- was performed. A set of novel potential p53 target genes was identified while many known target genes were found to be not transcriptionally activated during hypoxia. Follow up which was focused on how p53 affected hypoxia induced apoptosis showed that the death receptor Fas was critical.When small amounts of tissue are available, amplification of the transcript population is necessary for microarray analysis. A new strategy for amplification based on PCR was evaluated and compared to a commercial in vitro transcription protocol. Both protocols produced reliable results. Advantages with the PCR based method are a lower cost and a high flexibility due to compatibility with both sense and antisense strand microarrays.Keywords: adrenocortical tumour, apoptosis, cancer, classification, gene expression, microarray, p53, RNA amplification
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| 5. |
- Lundholm, Lovisa, et al.
(författare)
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Effects of estrogen on gene expression profiles in mouse hypothalamus and white adipose tissue: target genes include glutathione peroxidase 3 and cell death-inducing DNA fragmentation factor, alpha-subunit-like effector A.
- 2008
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 196:3, s. 547-57
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Tidskriftsartikel (refereegranskat)abstract
- Obesity has become a major health problem in many parts of the world. Estrogens are known to reduce adipose tissue mass in both humans and animals but the molecular mechanisms are not well characterized. We used gene expression profiling to study long-term effects of estrogen on gene expression in mouse white adipose tissue and hypothalamus. Overall, the effects of estrogen on hypothalamic gene expression were much smaller than the corresponding effects on white adipose tissue gene expression. We characterize in detail estrogenic regulation of glutathione peroxidase 3 (GPX3). Our studies suggest that GPX3 is a direct estrogen receptor alpha target gene in white adipose tissue. Since obesity is correlated with oxidative stress, and GPX3 has been demonstrated to be lower in obesity and higher after weight loss, we hypothesize that GPX3 is one important mediator of effects of estrogen in relation to fat mass. Additional genes that were affected by estrogen in adipose tissue include cell death-inducing DNA fragmentation factor, alpha-subunit-like effector A (CIDEA), a gene shown to be related to body fat in mice. We conclude that estrogen has large effects on gene expression in white adipose tissue and hypothesize that GPX3 and CIDEA could be important mediators of the effects of estrogen on fat mass.
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| 6. |
- Salmela, Elina, et al.
(författare)
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Genome-wide analysis of single nucleotide polymorphisms uncovers population structure in Northern Europe
- 2008
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Ingår i: PLOS ONE. - San Fransisco : Public library of science. - 1932-6203. ; 3:10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genome-wide data provide a powerful tool for inferring patterns of genetic variation and structure of human populations.Principal Findings: In this study, we analysed almost 250,000 SNPs from a total of 945 samples from Eastern and Western Finland, Sweden, Northern Germany and Great Britain complemented with HapMap data. Small but statistically significant differences were observed between the European populations (F(ST) = 0.0040, p < 10(-4)), also between Eastern and Western Finland (F(ST) = 0.0032, p < 10(-3)). The latter indicated the existence of a relatively strong autosomal substructure within the country, similar to that observed earlier with smaller numbers of markers. The Germans and British were less differentiated than the Swedes, Western Finns and especially the Eastern Finns who also showed other signs of genetic drift. This is likely caused by the later founding of the northern populations, together with subsequent founder and bottleneck effects, and a smaller population size. Furthermore, our data suggest a small eastern contribution among the Finns, consistent with the historical and linguistic background of the population.Significance: Our results warn against a priori assumptions of homogeneity among Finns and other seemingly isolated populations. Thus, in association studies in such populations, additional caution for population structure may be necessary. Our results illustrate that population history is often important for patterns of genetic variation, and that the analysis of hundreds of thousands of SNPs provides high resolution also for population genetics.
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| 7. |
- Zhao, Chunyan, et al.
(författare)
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Estrogen receptor beta 2 negatively regulates the transactivation of estrogen receptor alpha in human breast cancer cells
- 2007
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 67:8, s. 3955-3962
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens, by binding to and activating two estrogen receptors (ER alpha and ER beta), are critically involved in the development of the mammary gland and breast cancer. An isoform of ER beta, ER beta 2 (also called ER beta cx), with an altered COOH-terminal region, is coexpressed with ER alpha. in many human breast cancers. In this study, we generated a stable cell line from MCF7 breast cancer cells expressing an inducible version of ER beta 2, along with endogenous ER alpha, and examined the effects of ER beta 2 on the ER alpha protein levels and function. We showed that ER beta 2 inhibited ER alpha-mediated transactivation via estrogen response element and activator protein-1 sites of reporter constructs as well as the endogenous genes pS2 and MMP-1. Chromatin immunoprecipitation assays revealed that ER beta 2 expression caused a significant reduction in the recruitment of ER alpha to both the pS2 and MMP-1 promoters. Furthermore, ER beta 2 expression induced proteasome-dependent degradation of ER alpha. The inhibitory effects of ER beta 2 on ER alpha activity were further confirmed in HEK293 cells that lack functional endogenous ER alpha. We also showed that ER beta 2 can interact with ER alpha both in vitro and in mammalian cells' which is compatible with a model where ER beta 2/ER alpha heterodimers are targeted to the proteasome. Finally, in human breast cancer samples, we observed that expression of ER beta 2 significantly correlated with ER alpha-negative phenotype. Our data suggest that ER beta 2 could influence ER alpha-mediated effects relevant for breast cancer development, including hormone responsiveness.
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