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- Vallhov, H., et al.
(författare)
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The effect of gold nanoparticles on dendritic cells
- 2006
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Ingår i: 2006 NSTI Nanotechnology Conference and Trade Show. - 0976798565 - 9780976798569
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Konferensbidrag (refereegranskat)abstract
- Gold is recognized as one of the most biocompatible and stable materials, and has been used for many years as a medical agent, among others in the form of salt for the treatment of rheumatoid arthritis [1]. More recent biological applications have been focusing on using gold nanoparticles for drug and gene delivery [2], or as a photothermal agent causing highly localized heating applicable in cancer therapy [3]. There is however very little information available concerning what influence such particles have on the immune system, e.g. on dendritic cells (DCs). DCs are present throughout the human body but are particularly localized at antigen-exposed sites, such as the skin. They are the most efficient type of antigen presenting cells having a capacity both to initiate primary and secondary immune responses, by expressing cytokines, MHC and co-stimulatory molecules such as CD80, CD83 and CD86 [4-5]. DCs decide whether an immune response should be initiated and are able to affect the development of T-helper cells into Treg-, Th1- or Th2-cells depending on their cytokines produced and their expression of co-stimulatory molecules [6]. We addressed the question whether spherical gold nanoparticles of 6 nm in diameter affect DCs, looking at morphology, viability, expression of cytokines and of co-stimulatory and antigen presenting molecules. This was assessed by using human monocyte derived DCs (myeloid DCs) and peripheral blood mononuclear cells from healthy blood donors together with gold nanoparticles [7], and various techniques including light microscopy, flow cytometry and ELISpot. After having overcome aggregation problems of gold nanoparticles by stabilizing with human serum albumin (HSA) and developed methods to produce nanoparticles with low lipopolysaccharide (LPS) contamination, experiments revealed that both morphology and viability were not affected by the gold nanoparticles. The expression of CD80, CD83, CD86 and MHC class II was only to a minor degree up-regulated after 6 and 24 h, and CD40 and MHC class I was not affected, which indicates biocompatibility of gold nanoparticles. This is further supported by low or no expression of the cytokines IL-10, IL-12 and IFN-alpha. HSA by itself did not have an effect on the DCs. In conclusion, gold nanoparticles of 6 nm in diameter are highly unlikely to initiate a danger signal to the immune system through the dendritic cells, and have therefore the potential to be used as inert carriers in biomedical applications.
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- Admyre, C, et al.
(författare)
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Exosomes - nanovesicles with possible roles in allergic inflammation.
- 2008
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Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 63:4, s. 404-8
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Forskningsöversikt (refereegranskat)abstract
- Exosomes are nano-sized membrane vesicles which are released extracellularly after fusion of multivesicular endosomes with the cell membrane. Despite their characteristic composition of proteins compared to the cell membrane, no exosome-specific molecule has so far been characterized. Exosomes are found in bronchoalveolar lavage (BAL), urine, serum and breast milk, and are released from several cells implicated in allergy including mast cells, dendritic cells (DC), T cells and epithelial cells. Antigen-loaded exosomes have been shown to be highly immunogenic and we propose that exosomes could be a modulating factor in allergic responses. Allergen-presenting exosomes could transport allergen and stimulate allergen-specific T cells, and possibly also biasing T cell responses depending on the molecules present on the exosome surface. Furthermore, exosomes from mast cells, highly active in allergic reactions, have been found to induce DC maturation and also to be able to transport functional RNA to recipient cells, suggesting a new pathway for cell communication. Reversely, tolerizing exosomes e.g. tolerosomes, from gut or breast milk, could block an allergic response or prevent allergy development. A better understanding of the role of exosomes in allergies could make us understand how allergy can be prevented or lead to the development of more efficient treatments.
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- Gabrielsson, Britt, 1957, et al.
(författare)
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Evaluation of reference genes for studies of gene expression in human adipose tissue.
- 2005
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Ingår i: Obesity research. - 1071-7323 .- 1550-8528. ; 13:4, s. 649-52
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to evaluate reference genes for expression studies of human adipose tissue. RESEARCH METHODS AND PROCEDURES: Using 52 human adipose tissue expression profiles (HU95), 10 putative reference genes with the lowest variation in expression levels were selected for further studies. Expression stability of these 10 novel and 5 previously established reference genes was evaluated by real-time reverse transcriptase-polymerase chain reaction analysis. For this purpose, 44 adipose tissue biopsies from 27 subjects were chosen to include a wide range of parameters such as sex, age, BMI, depot origin, biopsy procedure, and effects of nutrition. RESULTS: LRP10 was identified as the gene with the least variation in expression levels. The frequently used reference genes RPLP0, 18S rRNA, PPIA, ACTB, and GAPD were ranked as 4, 6, 7, 8, and 10, respectively. DISCUSSION: Our results suggest that LRP10 is a better choice as reference for expression studies of human adipose tissue compared with the most frequently used reference genes.
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- Jernås, Margareta, 1961, et al.
(författare)
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Separation of human adipocytes by size: hypertrophic fat cells display distinct gene expression
- 2006
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Ingår i: The FASEB Journal. - : Wiley. - 1530-6860 .- 0892-6638. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Enlarged adipocytes are associated with insulin resistance and are an independent predictor of type 2 diabetes. To understand the molecular link between these diseases and adipocyte hypertrophy, we developed a technique to separate human adipocytes from an adipose tissue sample into populations of small cells (mean 57.6+-3.54 um) and large cells (mean 100.1+-3.94 um). Microarray analysis of the cell populations separated from adipose tissue from three subjects identified 14 genes, of which five immune-related, with more than fourfold higher expression in large cells than small cells. Two of these genes were serum amyloid A (SAA) and transmembrane 4 L six family member 1 (TM4SF1). Real-time RT-PCR analysis of SAA and TM4SF1 expression in adipocytes from seven subjects revealed 19-fold and 22-fold higher expression in the large cells, respectively, and a correlation between adipocyte size and both SAA and TM4SF1 expression. The results were verified using immunohistochemistry. In comparison with 17 other human tissues and cell types by microarray, large adipocytes displayed by far the highest SAA and TM4SF1 expression. Thus, we have identified genes with markedly higher expression in large, compared with small, human adipocytes. These genes may link hypertrophic obesity to insulin resistance/type 2 diabetes.
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