Marion C Dickson

Imperial College London, London, ENG, United Kingdom

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Publications (10)49.73 Total impact

  • Article: Discovery of GSK143, a highly potent, selective and orally efficacious spleen tyrosine kinase inhibitor.
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    ABSTRACT: The lead optimisation of the diaminopyrimidine carboxamide series of spleen tyrosine kinase inhibitors is described. The medicinal chemistry strategy was focused on optimising the human whole blood activity whilst achieving a sufficient margin over liability kinases and hERG activity. GSK143 is a potent and highly selective SYK inhibitor showing good efficacy in the rat Arthus model.
    Bioorganic & medicinal chemistry letters 08/2011; 21(20):6188-94. · 2.65 Impact Factor
  • Article: Reply.
    Arthritis & Rheumatism 07/2009; 60(7):2207-2208. · 7.87 Impact Factor
  • Article: Genetic association of the major histocompatibility complex with rheumatoid arthritis implicates two non-DRB1 loci.
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    ABSTRACT: The HLA-DRB1 locus within the major histocompatibility complex (MHC) at 6p21.3 has been identified as a susceptibility gene for rheumatoid arthritis (RA); however, there is increasing evidence of additional susceptibility genes in the MHC region. The aim of this study was to estimate their number and location. A case-control study was performed involving 977 control subjects and 855 RA patients. The HLA-DRB1 locus was genotyped together with 2,360 single-nucleotide polymorphisms in the MHC region. Logistic regression was used to detect DRB1-independent effects. After adjusting for the effect of HLA-DRB1, 18 markers in 14 genes were strongly associated with RA (P<10(-4)). Multivariate logistic regression analysis of these markers and DRB1 led to a model containing DRB1 plus the following 3 markers: rs4678, a nonsynonymous change in the VARS2L locus, approximately 1.7 Mb telomeric of DRB1; rs2442728, upstream of HLA-B, approximately 1.2 Mb telomeric of DRB1; and rs17499655, located in the 5'-untranslated region of DQA2, only 0.1 Mb centromeric of DRB1. In-depth investigation of the DQA2 association, however, suggested that it arose through cryptic linkage disequilibrium with an allele of DRB1. Two non-shared epitope alleles were also strongly associated with RA (P<10(-4)): *0301 with anti- cyclic citrullinated peptide-negative RA and *0701 independently of autoantibody status. These results confirm the polygenic contribution of the MHC to RA and implicate 2 additional non-DRB1 susceptibility loci. The role of the HLA-DQ locus in RA has been a subject of controversy, but in our data, it appears to be spurious.
    Arthritis & Rheumatism 12/2008; 60(1):53-62. · 7.87 Impact Factor
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    Article: Evidence of epistasis between interleukin 1 and selenoprotein-S with susceptibility to rheumatoid arthritis.
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    ABSTRACT: Selenoprotein-S (SELS) is involved in the stress response within the endoplasmic reticulum (ER) and inflammation. Recently, promoter variants in the SELS gene were shown to be associated with plasma levels of interleukin (IL)6, IL1beta and tumour necrosis factor (TNF). It was hypothesised that these variants could influence rheumatoid arthritis (RA) susceptibility and may interact with functional single nucleotide polymorphisms (SNPs) in the genes for IL1, IL6 and TNF. Genotyping was performed in 988 unrelated healthy controls and 965 patients with RA. Stratified analysis was used to test for interactions. Single gene effects and evidence of epistasis were investigated using the Mantel-Haenszel (M-H) test and the linkage disequilibrium (LD)-based statistic. No association of SELS -105 genotype and RA susceptibility was detected. Stratification of SELS -105 genotypes by IL1 -511 genotypes showed that the disease risk (comparing AA/GA to GG at the SELS -105 locus) in individuals with the GG/AG genotype at the IL1beta -511 locus was significantly lower than that in individuals having the AA genotype at the IL1beta -511 locus (odds ratio (OR): 0.9 and 2.3, respectively; p = 0.004 by M-H test). Significant epistasis was also detected using the LD-based statistic (p = <0.001). No interaction was observed between SELS -105 and IL6 or TNF variants. Our results reveal evidence of strong epistasis in two genes in the IL1 production pathway and highlight the potential importance of gene-gene interactions in the pathogenesis of RA.
    Annals of the rheumatic diseases 09/2008; 68(9):1494-7. · 8.11 Impact Factor
  • Article: Potential novel biomarkers of disease activity in rheumatoid arthritis patients: CXCL13, CCL23, transforming growth factor alpha, tumor necrosis factor receptor superfamily member 9, and macrophage colony-stimulating factor.
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    ABSTRACT: To determine whether the plasma levels of a range of inflammatory proteins have utility as biomarkers of disease activity in rheumatoid arthritis (RA) patients. Plasma proteins (n = 163) were profiled in 44 patients with RA diagnosed according to the American College of Rheumatology 1987 criteria (22 with active and 22 with quiescent disease) and in 16 age- and sex-matched healthy controls. The utility of a subset of differentially expressed proteins as predictors of RA disease activity was investigated using partial least-squares discriminant analysis, and their response to therapeutic intervention was evaluated in plasma from an additional cohort of 16 patients with active RA treated with anti-tumor necrosis factor alpha (anti-TNFalpha). The protein profiling study identified 25 proteins that were differentially expressed in plasma samples from patients with active RA (P for the false discovery rate < or = 0.01) compared with those with quiescent RA, including the previously described interleukin-6 (IL-6), oncostatin M, and IL-2, and the 5 less-established markers macrophage colony-stimulating factor (M-CSF), tumor necrosis factor receptor superfamily member 9, CCL23, transforming growth factor alpha, and CXCL13. Systemic levels of these 5 markers correlated with the C-reactive protein level, erythrocyte sedimentation rate, rheumatoid factor level, tender joint count in 68 joints, and Disease Activity Score in 28 joints (DAS28), and their combined plasma levels were shown to be good predictors of disease activity (kappa = 0.64). In anti-TNFalpha-treated RA patients, plasma levels of CXCL13 were reduced after 1 and 7 days of therapy, and levels of CCL23, M-CSF, and CXCL13 showed a statistically significant positive correlation with the DAS28 score. This exploratory study for biomarker discovery led to the identification of several proteins predictive of RA disease activity that may be useful in the definition of disease subphenotypes and in the measurement of response to therapy in clinical studies.
    Arthritis & Rheumatism 08/2008; 58(8):2257-67. · 7.87 Impact Factor
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    Article: The interferon induced with helicase domain 1 A946T polymorphism is not associated with rheumatoid arthritis.
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    ABSTRACT: An important feature of autoimmune diseases is the overlap of pathophysiological characteristics. Clustering of autoimmune diseases in families suggests that genetic variants may contribute to autoimmunity. The aim of the present study was to investigate the role of the interferon induced with helicase domain 1 (IFIH1) A946T (rs1990760 A>G) variant in rheumatoid arthritis (RA), as this was recently associated with susceptibility to type 1 diabetes. A total of 965 Caucasians with RA and 988 healthy controls were genotyped for IFIH1 A946T. Gene expression of IFIH1 was measured in peripheral blood leukocytes using real-time PCR. Genotypes were equally distributed in both RA cases and healthy controls (odds ratio for allele C = 0.9, 95% confidence interval = 0.8-1.0, P = 0.3). No association was detected after stratification by sex, age at onset, rheumatoid factor status, anti-cyclic citrullinated peptide status or radiological joint damage. Levels of IFIH1 mRNA were approximately twofold higher in blood leucocytes of RA cases compared with healthy controls (P < 0.0001). These results indicate that the IFIH1 is upregulated in RA but that the A946T variant does not contribute significantly to the genetic background of RA.
    Arthritis research & therapy 02/2007; 9(2):R40. · 4.27 Impact Factor
  • Article: 5-(1H-Benzimidazol-1-yl)-3-alkoxy-2-thiophenecarbonitriles as potent, selective, inhibitors of IKK-epsilon kinase.
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    ABSTRACT: The identification and hit-to-lead exploration of a novel, potent and selective series of substituted benzimidazole-thiophene carbonitrile inhibitors of IKK-epsilon kinase is described. Compound 12e was identified with an IKK-epsilon enzyme potency of pIC(50) 7.4, and has a highly encouraging wider selectivity profile, including selectivity within the IKK kinase family.
    Bioorganic & Medicinal Chemistry Letters 01/2007; 16(24):6236-40. · 2.55 Impact Factor
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    Article: Independent associations of anti-cyclic citrullinated peptide antibodies and rheumatoid factor with radiographic severity of rheumatoid arthritis.
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    ABSTRACT: Several recent publications have established a strong association between anti-cyclic citrullinated peptide antibody (anti-CCP)-positive rheumatoid arthritis (RA) and carriage of shared epitope (SE) alleles. Although anti-CCP have also been associated with more severe RA, the issue of whether this is independent of rheumatoid factor (RF) has not been addressed. To identify associations between RF, anti-CCP, SE status and radiological damage, we studied a large cross-sectional cohort with longstanding RA. Individuals (n = 872) enrolled in the study all fulfilled the American College of Rheumatology criteria for RA, had a minimum disease duration of 3 years, and at least one definite radiographic erosion was present in hands or feet. Radiographs were scored blind at study entry by a single musculoskeletal radiologist using a modified Larsen's score. Anti-CCP and RF levels were determined using enzyme-linked immunosorbent assay, and DRB1 typing was performed using polymerase chain reaction based methodology. Both anti-CCP and RF levels were strongly associated with radiographic severity (P < 0.0001). In subgroups stratified for both anti-CCP and RF status, evidence of independent associations of both antibodies with radiographic outcome was found (P < 0.0001). An association of SE alleles with radiographic severity was present only in RF-negative individuals. Anti-CCP positivity was associated with SE status with evidence of a gene-dose effect, most markedly in RF-negative individuals (P < 0.01). Anti-CCP and RF status are independent severity factors for RA, with SE alleles playing at most a secondary role. Our data support the view that previously described associations between SE and radiological severity, especially in RF-negative patients, may be indirect and due to an association with anti-CCP.
    Arthritis research & therapy 01/2006; 8(4):R128. · 4.27 Impact Factor
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    Article: Gene expression profiles in the rat streptococcal cell wall-induced arthritis model identified using microarray analysis.
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    ABSTRACT: Experimental arthritis models are considered valuable tools for delineating mechanisms of inflammation and autoimmune phenomena. Use of microarray-based methods represents a new and challenging approach that allows molecular dissection of complex autoimmune diseases such as arthritis. In order to characterize the temporal gene expression profile in joints from the reactivation model of streptococcal cell wall (SCW)-induced arthritis in Lewis (LEW/N) rats, total RNA was extracted from ankle joints from naive, SCW injected, or phosphate buffered saline injected animals (time course study) and gene expression was analyzed using Affymetrix oligonucleotide microarray technology (RAE230A). After normalization and statistical analysis of data, 631 differentially expressed genes were sorted into clusters based on their levels and kinetics of expression using Spotfire profile search and K-mean cluster analysis. Microarray-based data for a subset of genes were validated using real-time PCR TaqMan analysis. Analysis of the microarray data identified 631 genes (441 upregulated and 190 downregulated) that were differentially expressed (Delta > 1.8, P < 0.01), showing specific levels and patterns of gene expression. The genes exhibiting the highest fold increase in expression on days -13.8, -13, or 3 were involved in chemotaxis, inflammatory response, cell adhesion and extracellular matrix remodelling. Transcriptome analysis identified 10 upregulated genes (Delta > 5), which have not previously been associated with arthritis pathology and are located in genomic regions associated with autoimmune disease. The majority of the downregulated genes were associated with metabolism, transport and regulation of muscle development. In conclusion, the present study describes the temporal expression of multiple disease-associated genes with potential pathophysiological roles in the reactivation model of SCW-induced arthritis in Lewis (LEW/N) rat. These findings improve our understanding of the molecular events that underlie the pathology in this animal model, which is potentially a valuable comparator to human rheumatoid arthritis (RA).
    Arthritis research & therapy 01/2005; 7(1):R101-17. · 4.27 Impact Factor
  • Article: Fluid Shear Stress Modulation of Gene Expression in Endothelial Cells.
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    ABSTRACT: The vascular endothelium, lining the blood vessel wall, is constantly exposed to wall shear stresses generated by flowing blood. Gene regulation, critical for endothelial cell function, depends on complex interactions at the promoter level and utilizes overlapping signal transduction cascades to activate the expression of genes involved in many biological processes.
    Physiology 11/1998; 13:241-246.