| 1. |
- Pettersson, Ulf
(författare)
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Människoraser, finns dom?
- 2009
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Ingår i: Rasen och vetenskapen. - Uppsala : Centrum för multietnisk forskning / Programmet för studier kring Förintelsen och folkmord. - 9789197743426 ; , s. 13-22
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Föredrag från föreläsningsserien Rasen och vetenskapen vid Uppsala universitet våren 2008. Artikeln av professorn i medicinsk genetik Ulf Pettersson (Uppsala) behandlar rasbegreppets ställning i människans utvecklingshistoria inom genetiken.
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| 2. |
- Bin Kaderi, Mohamed Arifin, 1978-
(författare)
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Assessment of Novel Molecular Prognostic Markers in Chronic Lymphocytic Leukemia
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The clinical course of chronic lymphocytic leukemia (CLL) is highly heterogeneous, which has prompted the search for biomarkers that can predict prognosis in this disease. The IGHV gene mutation status and certain genomic aberrations have been identified as reliable prognostic markers of clinical outcome for this disorder. However, the search for more feasible prognostic markers in CLL is still being pursued. Recently, certain single nucleotide polymorphisms (SNPs) in the GNAS1, BCL2 and MDM2 genes and the RNA expression levels of the LPL, ZAP70, TCL1, CLLU1 and MCL1 genes were suggested as novel prognostic markers in CLL. In papers I-III, we performed genotyping analyses of the GNAS1 T393C, BCL2 -938C>A and MDM2 SNP309 polymorphisms in 268-418 CLL patients and related the genotypes with clinical data. Association studies between the polymorphisms and established prognostic markers (i.e. IGHV mutation status, genomic aberrations, CD38 expression) were also performed. Our studies did not find any significant relationship between these SNPs with either clinical outcome or other known prognostic markers in CLL. In paper IV, we measured the RNA expression levels of LPL, ZAP70, TCL1, CLLU1 and MCL1 in 252 CLL cases and correlated these levels with clinical outcome. Here, we verified that high expression of all these RNA-based markers, except MCL1, were associated with an unfavourable prognosis. We also confirmed a close relationship between IGHV mutation status and the RNA-based markers, especially for LPL and CLLU1 expression. Among the RNA-based markers, multivariate analysis revealed LPL expression as the strongest independent prognostic marker for overall survival and time to treatment. Furthermore, the RNA-based markers could add further prognostic information to established markers in subgroups of patients, with LPL expression status giving the most significant results. In summary, data from papers I-III could not verify the GNAS1 T393C, BCL2 -938C>A and MDM2 SNP309 polymorphisms as prognostic markers in CLL. Future SNP markers must hence be confirmed in large, independent cohorts before being proposed as prognostic marker in CLL. In paper IV, we conclude that LPL expression appears to be the strongest among the RNA-based markers for CLL prognostication. Further efforts to standardize LPL quantification are required before it can be applied in the clinical laboratory to predict clinical outcome in this disease.
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| 3. |
- Delgado Vega, Angélica María, 1982-
(författare)
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Dissecting the Genetic Basis of Systemic Lupus Erythematosus : The Pursuit of Functional Variants
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is a chronic and systemic autoimmune disease that primarily affects women during the childbearing years. SLE is characterized by the production of autoantibodies against nucleic acids and their interacting proteins. The exact molecular mechanisms leading to the breakdown of self-tolerance remain to a large extent unknown, but it is well established that they are influenced by both non-genetic (i.e. environmental and hormonal) and genetic factors. SLE is a complex, polygenic disease. Several susceptibility variants have been identified in SLE. However, the functional role in disease pathogenesis for the majority of them remains largely unknown.This thesis includes case-control association studies where the role of the genes TNFSF4 (Paper I), STAT4 (Paper II), CD226 (Paper III), and BLK (Papers IV and V) in the susceptibility of developing SLE was investigated. The primary focus was on the identification of the functional variants underlying the association. For each of these genes, fine mapping was performed using single nucleotide polymorphisms (SNPs), the linkage disequilibrium (LD) was characterized, and the association was narrowed down to specific haplotypes by means of several different statistical genetic strategies. Candidate variants were prioritized for further functional analysis on the basis of their potential effect on the gene function, their association, and/or biological plausibility. In Paper I, the association of TNFSF4 with SLE was validated and attributed to a risk haplotype tagged by SNPs rs1234317-T and rs12039904-T. Paper II provides evidence supporting the presence of at least two independent genetic effects within the STAT4 gene represented by rs3821236-A and rs7574865-A, which correlated with increased levels of gene expression. In Paper III, a functional allele in CD226 (rs727088-C) was identified, which was responsible for decreased levels in both mRNA and protein expression. In Paper IV, two independent genetic effects in the BLK gene were demonstrated. The first one comprised multiple regulatory variants in high LD that were enriched for NFκB and IRF4 binding sites and correlated with low BLK mRNA levels. The second was a low-frequency missense substitution (Ala71Thr) that decreased the BLK protein half-life. In Paper V, a genetic epistatic interaction between BANK1 rs10516487 (GG) and BLK rs2736340 (TT+TC) was demonstrated. Additional molecular analyses established that these molecules interact physically. These studies have contributed to the dissection of the genetic architecture of SLE. They highlight the allelic heterogeneity of the disease and provide functional links to the associated variants, which has significantly aided in the understanding of SLE disease pathogenesis.
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| 4. |
- Olsson, Malin, 1972-
(författare)
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Familial amyloidosis with polyneuropathy : studies of genetic factors modifying the phenotype of the disease
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background. Familial Amyloidosis with Polyneuropathy (FAP) is an autosomal dominantly inherited systemic amyloid disease. The disease is caused by mutations in the transthyretin (TTR) gene, where close to 100 different amyloidogenic mutations have been identified. FAP is found worldwide, but endemic areas with a high frequency of patients are found in Portugal, Japan and northern Sweden. Cases from these endemic areas all share the same TTR c.148G>A, p.V50M ("V30M") mutation, but the phenotype of the disease varies between the areas, and also within the endemic areas. The mean onset of the disease is two decades earlier in Portugal and Japan compared to Sweden, but late as well as early age at onset cases occur within all the populations. Interestingly, the different populations all display a maternal anticipation, where an earlier onset is observed for those individuals who inherit the trait from their mother. Since substantial variation in the phenotype is observed for different populations, epigenetic/genetic and/or environmental factors must exert a significant impact on the penetrance of the disease. Amyloid formation is caused by conformational changes of proteins, which facilitates their assembly into fibrils, amyloid. Oxidative stress can mediate conformational changes of proteins and since the mitochondria regulate oxidative processes within the cell, mitochondrial function may affect amyloid formation. The mitochondrial DNA is a non-nuclear DNA, which is entirely maternally inherited, and therefore could be related to the observed maternal anticipation of the disease. In addition, differences within the surrounding regions of the TTR gene may have an impact on the transcription of the gene and thereby on the expression of the different alleles. Material and methods. DNA from early and late onset V30M cases and from non-carriers (the latter utilised as controls) from Swedish, French, Japanese and Portuguese populations were analysed. In addition, DNA from healthy Swedish V30M carriers was analysed. Conventional analytical methods were employed, such as PCR, sequencing and genotyping. Conventional statistical methods used were t-test, Chi-squared test and maximum likelihood. Results. The study of V30M carrier frequency in two counties (Lycksele and Skellefteå) within the Swedish endemic area revealed a carrier frequency of 2.14% and 2.54%, respectively. The mitochondrial haplogroup analysis showed that in populations with generally late onset (French and Swedish), the haplogroup distribution of late onset cases resembled that of the controls derived from the same area, whereas haplogroup distribution for early onset patients was significantly different. The most pronounced difference was for the rare haplogroup K, of which early onset cases had a higher frequency than the controls. Analysis of the Portuguese population, with predominantly early onset, showed that haplogroup distribution for early onset cases were similar to the Portuguese control group, which had a different distribution than the Swedish control group. By analysis of pedigrees from Swedish and Portuguese patients it could be shown that mitochondrial genetic variation entirely could explain maternal anticipation in the Portuguese patients, whereas for Swedish patients, an additional parent of origin effect is present. Our analysis of the TTR gene disclosed a polymorphism (rs62093482) in the 3'UTR region of the Swedish patients. This polymorphism was found in all V30M carriers, irrespective of symptoms. In addition, homozygous TTR V30M carriers were homozygous also for the polymorphism. Since Swedish patients share a common founder this polymorphism thus is localised on the V30M allele. This polymorphism was found in only 4% of the Swedish controls. French controls showed the same frequency, but none of the French V30M patients displayed the polymorphism. In the Japanese population the polymorphism was not present at all. Interestingly, this polymorphism generates a potential binding site for microRNA and thereby possibly could down-regulate the expression of the mutated TTR allele. Conclusions. The carrier frequency in the endemic area is remarkably high, above 2% in the Lycksele and Skellefteå areas. The prevailing haplogroup distributions in the different endemic areas are consistent between the general population and the patient group with the predominant phenotype of that area. Mitochondrial genetic differences may explain maternal anticipation in Portuguese patients, and have an influence in Swedish patients. A polymorphism in the 3'UTR regulatory region of the mutated TTR allele is found in all Swedish patients. This polymorphism may down-regulate TTR V30M expression and thereby contribute to the late onset of the disease noted in the Swedish population.
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| 5. |
- Norberg, Maria, 1976-
(författare)
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In Vitro Drug Sensitivity and Apoptosis in Chronic Lymphocytic Leukemia
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chronic lymphocytic leukemia (CLL) is a heterogeneous malignancy displaying varying clinical outcome, where molecular markers today can divide patients into prognostic subgroups. Despite the introduction of new agents for treatment, remissions are usually not sustained in CLL and resistance towards treatment can partly be explained by aberrant apoptosis. The aim of this thesis was to find new drugs for CLL patients resistant to conventional therapy and to analyze genes involved in apoptosis within different prognostic subgroups. In paper I-II, the in vitro activity of substances was investigated using the fluorometric microculture cytotoxicity assay (FMCA). When evaluating rapamycin (paper I), an inhibitor of mTOR, in 97 tumor samples from different entities, CLL was found to be one of the most sensitive tumor types. Combination experiments on patient CLL cells indicated that rapamycin acted synergistically with the CLL drugs vincristine and chlorambucil. An investigation of 20 anti-cancer agents in cells from 40 CLL patients (paper II) revealed that prednisolone and rolipram displayed high activity in poor-prognostic patients, in particular IGHV unmutated CLL. Furthermore, when used in combination these agents were found to produce a synergistic effect. In paper III, the anti-apoptotic BCL2 family member BFL1 was evaluated in 37 CLL cases. Levels of BFL1 were higher in fludarabine-resistant patients compared to fludarabine-sensitive patients. In addition, the high expression of BFL1 inversely correlated to fludarabine-induced apoptosis in CLL cells. A single nucleotide polymorphism in the anti-apoptotic BCL2 gene (-938C>A) has been suggested as a novel poor-prognostic marker in CLL. In paper IV, we investigated this BCL2 polymorphism in 268 CLL patients and correlated genotypes to clinical data. However, no association could be confirmed between this polymorphism and clinical outcome or established prognostic markers. In conclusion, this thesis has shown that rapamycin is a potential drug for treatment in CLL. Furthermore, prednisolone and rolipram were identified as interesting candidates for treatment of poor-prognostic patients. Finally, the anti-apoptotic protein BFL1 may contribute to chemoresistance and hence represents a potential therapeutic target in CLL, whereas from our data, the BCL2 -938C>A polymorphism does not appear to have any prognostic significance.
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| 6. |
- Nord, Helena, 1980-
(författare)
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Application of Genomic and Expression Arrays for Identification of new Cancer Genes
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Copy number variation (CNV) comprises a recently discovered kind of variation involving deletion and duplication of DNA segments of variable size, ranging from a few hundred basepairs to several million. By altering gene dosage levels or disrupting proximal or distant regulatory elements CNVs create human diversity. They represent also an important factor in human evolution and play a role in many disorders including cancer. Array-based comparative genomic hybridization as well as expression arrays are powerful and suitable methods for determination of copy number variations or gene expression changes in the human genome. In paper I we established a 32K clone-based genomic array, covering 99% of the current assembly of the human genome with high resolution and applied it in the profiling of 71 healthy individuals from three ethnic groups. Novel and previously reported CNVs, involving ~3.5% of the genome, were identified. Interestingly, 87% of the detected CNV regions overlapped with known genes indicating that they probably have phenotypic consequences. In papers II through IV we applied this platform to different tumor types, namely two collections of brain tumors, glioblastoma (paper II) and medulloblastoma (paper III), and a set of bladder carcinoma (paper IV) to identify chromosomal alterations at the level of DNA copy number that could be related to tumor initiation/progression. Tumors of the central nervous system represent a heterogeneous group of both benign and malignant neoplasms that affect both children and adults. Glioblastoma and medulloblastoma are two malignant forms. Glioblastoma often affects adults while the embryonal tumor medulloblastoma is the most common malignant brain tumor among children. The detailed profiling of 78 glioblastomas, allowed us to identify a complex pattern of aberrations including frequent and high copy number amplicons (detected in 79% of samples) as well as a number of homozygously deleted loci. These regions encompassed not only previously reported oncogenes and tumor suppressor genes but also numerous novel genes. In paper III, a subset of 26 medulloblastomas was analyzed using the same genomic array. We observed that alterations involving chromosome 17, especially isochromosome 17q, were the most common genomic aberrations in this tumor type, but copy number alterations involving other chromosomes: 1, 7 and 8 were also frequent. Focal amplifications, on chromosome 1 and 3, not previously described, were also detected. These loci may encompass novel genes involved in medulloblastoma development. In paper IV we examined for the presence of DNA copy number alterations and their effect on gene expression in a subset of 21 well-characterized Ta bladder carcinomas, selected for the presence or absence of recurrences. We identified a number of novel genes as well as a significant association between amplifications and high-grade and recurrent tumors which might be clinically useful. The results derived from these studies increase our understanding of the genetic alterations leading to the development of these tumor forms and point out candidate genes that may be used in future as targets for new diagnostic and therapeutic strategies.
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| 7. |
- Afrakhte, Mozhgan
(författare)
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Growth control mechanisms in normal and neoplastic mammalian cells
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main theme of the studies presented in this thesis is, the growth control mechanisms whose loss in normal cells predispose to or cause cancer. The balance between growth inhibitory and stimulatory mechanisms is crucial for the development and maintenance of a normal animal.PDGF, a growth factor for cells of mesenchymal origin, is implicated in normal developmental processes as well as neoplasia. The alternative splicing of exon 6 in PDGF-A gene transcripts gives rise to two different proteins with different compartmentalization properties. The PDGF-A chain homodimers, PDGF-AAL, encoded PDGF A-splice variant remain associated with the cell membrane. Studies of a human fibrosarcoma cell line, U-2197, revealed a high expression level of the cell associated PDGF-AAL which upon release increased autophosphorylation of the endogenous PDGF receptors, suggesting an autocrine loop. PDGF-A gene and PDGFR-α gene found to be co-amplified in the U-2197, indicating an optimised system for growth in these cells, i.e. amplified growth factor receptor as well as a local autocrine supply of the mitogen.Members of TGFβ superfamily are potent regulators of the growth and differentiation of a wide range of cell types. Intracellular mediators of TGF-β signalling, SMADs, transduce signals from serine/threonine kinase receptors to the nucleus where they affect transcription of target genes. A new class of SMAD proteins has been identified whose members, the inhibitory SMADS, antagonise TGF-β signals by interfering with agonistic SMADs activity. Smad6 and Smad7 are two closely related TGF-β antagonists identified in mammalian cells. Overexpression of Smad7 inhibited the cellular response to TGF-β whereas expression of an anti-sense Smad7 construct showed an enhancing effect on this response. The inhibitory SMADs may act in a negative feedback loop, as their expression is induced by the same ligands whose action they antagonise.Density dependent growth inhibition is a growth control mechanism often lost in transformed and malignant cells. Cells in dense culture are refractory to the mitogen stimulation although, the mitogenic signals were shown to be processed to some extent. The expression of immediate-early genes in dense culture stimulated with mitogen was induced. The activity of cyclin dependent kinases (CDKs), the pivotal kinases in G1/S transition, showed to be density dependent and decreased by increasing cell density. pRb, a tumour suppressor and growth regulatory protein, remained unphosphorylated in mitogen treated dense culture. The cessation of CDKs kinase activity in dense cultures was shown to be accompanied with increasing expression of inhibitory proteins of these kinases, CKIs. The impaired expression of a positive regulator of CDKs, Cdc25A phosphatase, was another feature of dense cultures.
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| 8. |
- Antson, Dan-Oscar
(författare)
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Genotyping RNA and DNA using padlock probes
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Novel techniques are needed to investigate the genetic variation revealed in the first draft of the human genome sequence. Padlock probes are recently developed reagents, suitable for detecting single-nucleotide variations of DNA and RNA in situ or in solution. The probes are oligonucleotides of about 70-140 nucleotides that can be circularized by ligation in the presence of a correct target sequence. Standard chemical synthesis of padlock probes is difficult due to the requirement for intact 5' and 3' ends of these long oligonucleotides. A novel PCR-based method is presented in this thesis, whereby longer, densely labeled padlock probes can be made as compared to conventional chemical synthesis. PCR-generated padlock probes produced a stronger signal and a more resolved staining pattern, compared to chemically synthesized probes in fluorescence in situ analysis of an alpha-satellite sequence variant present in human chromosomes 13 and 21. Padlock probes used for in situ analysis of metaphase chromosomes had an optimal length of 140 nucleotides. They were used to identify individual chromosomes 7 and 15, and to follow the transmission of chromosome homologues for two consecutive generations. The specificity of the padlock probes to detect single copy genes in genomic DNA samples was demonstrated by detecting a single-nucleotide mutation in the ATP7B gene. It has not previously been known if T4 DNA ligase can be used for RNA sequence analysis. In this thesis, it is demonstrated that T4 DNA ligase can be used for distinguishing single-nucleotide RNA sequence variants. Reaction conditions were defined where most mismatches could be discriminated by a factor of 80 and all mismatches by a factor of at least 20. Under these conditions padlock probes could detect and distinguish RNA sequence variants with ligation efficiency almost as high as on the corresponding DNA sequence. A detailed study of the parameters influencing RNA-templated DNA ligation revealed that DNA ligation on RNA templates proceeds at a much slower rate compared to the same reaction on DNA, and that a molar excess of enzyme is required. Furthermore, the ligation reaction is inhibited by high concentrations of the cofactor ATP and NaCl. The work presented in this thesis demonstrates that PCR-generated padlock probes can detect and distinguish single-nucleotide variation in both RNA and DNA.
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| 9. |
- Aspegren, Anders
(författare)
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Nuclear Organization of Gene Expression in Adenovirus Infected Cells
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Adenovirus infected cells provide a good model system for studying nuclear organization during RNA production and transport. This thesis is focused on the dynamic organization of splicing factors during the late phase of Adenovirus infection in HeLa cells, the nuclear localization of viral RNA, and the pathway used for viral RNA transport to the cytoplasm.Splicing factors are relocalized from interchromatin granule clusters to sites of transcription in Adenovirus infected cells at intermediate times of infection. Later, splicing factors and viral RNA accumulate posttranscriptionally in interchromatin granule clusters. The release of the splicing factors from transcription sites was energy dependent or preceded by energy requiring mechanisms. Our data indicated that phosphorylation events inhibited by staurosporine, and 3' cleavage of the transcript are two possible mechanisms involved prior to the release of the RNP complex from transcription sites.A viral protein derived from orf6 of early region 4, 34K, is important for the nuclear stability and transport of late viral mRNA derived from the major late transcription unit. A viral mutant lacking this region is defective for posttranscriptional accumulation of viral mRNA in interchromatin granule clusters, and for the accumulation of viral RNA in the cytoplasm. These results suggest that posttranscriptional accumulation of viral RNA in interchromatin granule clusters may contribute to the maturation of the RNP complex or sorting of RNAs and proteins, to prepare the final RNP complex for transport to the cytoplasm.A previous model suggested that adenoviral late mRNA is transported to the cytoplasm by utilizing the CRM-1 pathway. This pathway can be blocked by the drug leptomycin B. The data presented in paper IV suggests that this model might not be applicable, since leptomycin B did not inhibit adenoviral late gene expression.
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| 10. |
- Ata, Ahmad Khaled
(författare)
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Expression of TGF- isoforms, their receptors and related SMAD proteins in brain pathology : Immunohistochemical studies focusing on infarcts, abscesses and malignant gliomas
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the immunohistochemical expression of transforming growth factor beta(TGFβ) isoforms, their receptors and TGF-β-related SMAD proteins in brain pathology, chiefly in-farcts. One key question was whether the expressions of these compounds are altered within glial cells, endothelial cells of microvessels and other cell types in the vicinity of infarcts. Studies on human and animal brain infarcts were made. Immunoreactivities to TGF-β isoforms -β1, -β2 and -β3, and TGF-βreceptor (TβR) type I were seen in astrocytes, macrophages, neurons, endothelial and vascular smooth muscle cells of human brain infarcts. Similar observations were made in an experimental model of rat brain infarct at day 1 and 3 following occlusion of the middle cerebral artery (MCA). Increased expression of Smad2, -3, -4, -6 and -7 was seen already at 6 h after MCA occlusion in neurons, microvascular endothelial cells, astroglial cells and inflammatory cells. Later on, immunopositive macrophages were present in the infarcts. The changes persisted even at day 7 after MCA occlusion.Several alterations thus occur during the evolution of brain infarcts with regard to the immunohistochemical expression of TGF-β, its receptors and related SMAD proteins. Such changes are, however, not unique to brain infarcts. Thus, patterns of high expression for TGF-β- isoforms -β1, -β2 -β3, and TβR-I in cases of brain abscess (human), and of Smad2, -3, -4, -6 and -7 in tumor cells and neoplastic blood vessels of malignant gliomas (human) were also observed.In addition, immunohistochemical expression of vascular endothelial growth factor (VEGF) andits receptors was investigated since this growth factor is involved in angiogenesis and edemaformation, two cardinal features of brain infarcts. Increased immunoreactivities, seen particularly in the edges of infarcts, were observed already at day 1 after MCA occlusion.In conclusion, the various TGF-β isoforms, receptors and related SMAD proteins, together with other factors, seem to be involved in the very complicated and important changes taking place in the vicinity of brain infarcts.
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