| 1. |
- Bengtsson, Torbjörn, et al.
(författare)
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The periodontal pathogen Porphyromonas gingivalis cleaves apoB-100 and increases the expression of apoM in LDL in whole blood leading to cell proliferation
- 2008
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Ingår i: Journal of Internal Medicine. - : Institutionen för medicin och hälsa. - 0954-6820 .- 1365-2796. ; 263:5, s. 558-571
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Several studies support an association between periodontal disease and atherosclerosis with a crucial role for the pathogen Porphyromonas gingivalis. This study aims to investigate the proteolytic and oxidative activity of P. gingivalis on LDL in a whole blood system by using a proteomic approach and analyze the effects of P. gingivalis-modifed LDL on cell proliferation.Methods: The cellular effects of P. gingivalis in human whole blood were assessed using lumi-aggregometry analyzing reactive oxygen species (ROS) production and aggregation. Blood was incubated for 30 min with P. gingivalis, whereafter LDL was isolated and a proteomic approach was applied to examine protein expression. LDL-oxidation was determined by analyzing the formation of protein carbonyls. The effects of P. gingivalis-modifed LDL on fibroblast proliferation were studied using the MTS-assay.Results: Incubation of whole blood with P. gingivalis caused an extensive aggregation and ROS-production, indicating platelet and leukocyte activation. LDL prepared from the bacteria-exposed blood showed an increased protein oxidation, elevated levels of apoM and formation of two apoB-100 N-terminal fragments. P. gingivalis-modified LDL markedly increased the growth of fibroblasts. Inhibition of gingipain R suppressed the modification of LDL by P. gingivalis.Conclusions: The ability of P. gingivalis to change the protein expression and the proliferative capacity of LDL may represent a crucial event in periodontitis-associated atherosclerosis.
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| 2. |
- Lyon, Helen N., et al.
(författare)
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The association of a SNP upstream of INSIG2 with body mass index is reproduced in several but not all cohorts
- 2007
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 3:4
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Tidskriftsartikel (refereegranskat)abstract
- A SNP upstream of the INSIG2 gene, rs7566605, was recently found to be associated with obesity as measured by body mass index (BMI) by Herbert and colleagues. The association between increased BMI and homozygosity for the minor allele was first observed in data from a genome-wide association scan of 86,604 SNPs in 923 related individuals from the Framingham Heart Study offspring cohort. The association was reproduced in four additional cohorts, but was not seen in a fifth cohort. To further assess the general reproducibility of this association, we genotyped rs7566605 in nine large cohorts from eight populations across multiple ethnicities (total n = 16,969). We tested this variant for association with BMI in each sample under a recessive model using family-based, population-based, and case-control designs. We observed a significant (p < 0.05) association in five cohorts but saw no association in three other cohorts. There was variability in the strength of association evidence across examination cycles in longitudinal data from unrelated individuals in the Framingham Heart Study Offspring cohort. A combined analysis revealed significant independent validation of this association in both unrelated (p = 0.046) and family-based (p = 0.004) samples. The estimated risk conferred by this allele is small, and could easily be masked by small sample size, population stratification, or other confounders. These validation studies suggest that the original association is less likely to be spurious, but the failure to observe an association in every data set suggests that the effect of SNP rs7566605 on BMI may be heterogeneous across population samples.
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| 3. |
- Skoglund, Caroline, 1981-, et al.
(författare)
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C-reactive protein and C1q regulate platelet adhesion and activation on adsorbed immunoglobulin G and albumin.
- 2008
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Ingår i: Immunology and cell biology. - : Wiley. - 0818-9641 .- 1440-1711. ; 86:5, s. 466-74
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Tidskriftsartikel (refereegranskat)abstract
- Blood platelets and C-reactive protein (CRP) are both used clinically as markers of ongoing inflammation, and both participate actively in inflammatory responses, although the biological effects are still incompletely understood. Rapidly adhering platelets express receptors for complement factor 1q (C1q) and the Fc part of immunoglobulin G (IgG), and CRP is known to activate/regulate complement via C1q binding, and to ligate FcgammaRs. In the present study, we used normal human IgG pre-adsorbed to a well-characterized methylated surface as a model solid-phase immune complex when investigating the effects of CRP and C1q on platelet adhesion and activation. Protein adsorption was characterized using ellipsometry and polyclonal antibodies, and human serum albumin (HSA) and non-coated surfaces were used as reference surfaces. Platelet adhesion to IgG and HSA was inhibited by both C1q and CRP. Furthermore, CRP (moderately) and C1q (markedly) decreased the spreading of adhering platelets. The combination of C1q and CRP was slightly more potent in reducing cell adhesion to IgG, and also impaired the adhesion to HSA and non-coated surfaces. Platelet production of thromboxane B2 (TXB(2)) was also reduced by C1q both in the presence and absence of CRP, whereas CRP alone had no effect on TXB(2) production. We conclude that CRP and C1q regulate the behaviour of platelets, and that this may be an important immunoregulatory mechanism during inflammatory conditions.
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| 4. |
- Skoglund, Caroline, 1981-, et al.
(författare)
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C-reactive protein inhibit complement-mediated platelet activation suggesting a protective role in atherogenesis
- 2006
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Ingår i: Atherosclerosis Supplements. - Clare, Ireland : Elsevier. - 1567-5688 .- 1878-5050. ; 7:3, s. 284-284
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Objective: C-reactive protein (CRP) represents a powerful predictor of coro- nary artery disease. However, its physiological role is not fully understood. The binding of CRP to its ligand phosphorylcholine (PC) activates the com- plement system via the classical pathway, although limited to the initial stages, i.e. no membrane attack complex is formed. The aim of this study was to chaxacterize CRP-induced complement activation on PC-coated surfaces, and to investigate the regulatory effects of PC-bound crp on complement induced platelet activation.Methods: PC conjugated to keyhole limpet hemocyanin was immobilized to cross-linked fibrinogen on silica particles. Ellipsometry and polyclonal anti- bodies were used to quantify deposition of serum proteins, complement factors and CRP on the surfaces. Washed platelets as well as serum were prepared according to standard protocols. CRP concentrations were measured with a high sensitivity assay. Lumi-aggregometry was used to evaluate the effects of PC-coated particles and CRP on complement-induced platelet aggregation and secretion.Results: Serum (5%) induced platelet aggregation and secretion through complement-dependent mechanisms. PC-coated particles antagonized the complement-mediated platelet activation but only if CRP was present. Inter- estingly, we found that a minor elevation of CRR below 5 rag/1 was sufficient to inhibit platelet activation.Conclusions: We suggest that CRP bound to PC-expressing ligands, e.g. bacteria or modified low-density lipoproteins in an atherosclerotic lesion, modulate complement activation and thereby prevent a harmful platelet activation.
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