| 1. |
- Gunnar, Ronquist, et al.
(författare)
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Exosomen-intercellulär signalbärare med framtidspotential
- 2013
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Ingår i: Läkartidningen. - 0023-7205. ; 110:46
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Tidskriftsartikel (refereegranskat)abstract
- Exosomer frisätts från kroppens alla celler. De utgör ett nyupptäckt intercellulärt signalsystem. Välstuderade områden är immunologi, inflammation och allergi med applikation inom bla cancervård, urologi och kardiologi. Man kan förvänta sig att exosomer kommer att kunna användas inom både diagnostik och terapi.
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| 2. |
- Hedlund, Malin, 1981-
(författare)
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Exosomes and the NKG2D receptor-ligand system in pregnancy and cancer : using stress for survival
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although not obvious at first sight, several parallels can be drawn between pregnancy andcancer. Many proliferative, invasive and immune tolerance mechanisms that supportnormal pregnancy are also exploited by malignancies to establish a nutrient supply andevade or edit the immune response of the host. The human placenta, of crucial importancefor pregnancy success, and its main cells, the trophoblast, share several features withmalignant cells such as high cell proliferation rate, lack of cell-contact inhibition andinvasiveness. Both in cancer and in pregnancy, the immune defense mechanisms,potentially threatening the survival of the tumor or the fetus, are progressively blunted oreven turned into tumor- or pregnancy-promoting players. Amongst immune mechanisms that are meant to protect the host from cancer and can be apotential threat to the fetus, the NKG2D receptor-ligand system stands out as the mostpowerful, stress-inducible “danger detector” system that comprises the activating NK cellreceptor NKG2D and its ligands, the MIC (MHC class I Chain-related proteins A and B)and ULBP (UL-16 Binding Proteins) families. It is the major cytotoxic mechanism in thebody promoting surveillance and homeostasis. In the present thesis we investigate theNKG2D receptor-ligand system in human early normal pregnancy and in theleukemia/lymphoma cell lines Jurkat and Raji and ask the questions “How is the NKG2Dreceptor-ligand system functioning in pregnancy and tumor? How is the danger of cytotoxicattack of the fetus avoided? Why is the immunosurveillance function compromised incancer patients?” We developed a method to isolate and culture villous trophoblast from early human normalplacenta and used it to study the NKG2D receptor-ligand system. We discovered that theNKG2D ligand families of molecules MICA/B and ULBP1-5 are constitutively expressedby the syncytiotrophoblast of the chorionic villi. Using immnunoelectron microscopy, westudied the expression of these molecules at the subcellular level and could show for thefirst time that they are preferably expressed on microvesicles in multivesicular bodies(MVB) of the late endosomal compartment and are secreted as exosomes. Exosomes arenanometer sized microvesicles of endosomal origin, produced and secreted by a great7variety of normal and tumor cells. The exosomes are packages of proteins and ribonucleicacids that function as “mail” or “messengers” between cells conveying different biologicalinformation. We isolated and studied exosomes from placental explant cultures. We foundthat they carry NKG2D ligands on their surface and are able to bind and down-regulate thecognate receptor on NK-, CD8+ and T cells. The down-regulation selectively causedimpairment of the cytotoxic response of the cells but did not affect their lytic ability asmeasured by perforin content and gene transcription. Thus, the NKG2D ligand-bearingexosomes suppress the cytotoxic activity of the cells in the vicinity of the placenta, leavingtheir cytolytic machinery intact, ready to function when the cognate receptor isrestored/recycled. These findings highlight the role of placental exosomes in the fetalmaternalimmune escape and support the view of placenta as an unique immunomodulatoryorgan. Next, we studied the expression and exosomal release of NKG2D ligands by tumor cellsusing the leukemia cell lines Jurkat and Raji as a tumor model. We found that NKG2Dligand-bearing exosomes with similar immunosuppressive properties as placental exosomesare constitutively secreted by the tumor cells, as a mechanism to blunt the cytotoxicresponse of the immune cells and thus protect themselves from cytotoxic attack by the host.Interestingly, we found that thermal- and oxidative stress up-regulates the exosomesecretion and the amount of exosome-secreted NKG2D ligands. Our results imply thattumor therapies that cause stress-induced damage, such as thermotherapy and stripping ofoxygen supply to the tumor, might have a previously unrecognized side effect causingenhanced exosome production and secretion, which in turn suppresses the natural antitumorimmune response and thus should be taken into account when designing an optimaltherapy of cancer patients. In conclusion, we describe a novel stress-inducible mechanism shared by placenta andtumors as an immune escape strategy. We found that placenta- and tumor-derived NKG2Dligand-bearing exosomes can suppress immune responses to promote the survival and wellbeing of the fetus or the tumor. Our work comprises an important contribution to theelucidation of the NKG2D ligand-receptor system and its mode of operation in the humanbody and opens new perspectives for designing novel therapies for infertility and cancer.
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| 3. |
- Kalra, Hina, et al.
(författare)
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Vesiclepedia : a compendium for extracellular vesicles with continuous community annotation
- 2012
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Ingår i: PLoS biology. - : Public library of science. - 1544-9173 .- 1545-7885. ; 10:12, s. e1001450-
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular vesicles (EVs) are membraneous vesicles released by a variety of cells into their microenvironment. Recent studies have elucidated the role of EVs in intercellular communication, pathogenesis, drug, vaccine and gene-vector delivery, and as possible reservoirs of biomarkers. These findings have generated immense interest, along with an exponential increase in molecular data pertaining to EVs. Here, we describe Vesiclepedia, a manually curated compendium of molecular data (lipid, RNA, and protein) identified in different classes of EVs from more than 300 independent studies published over the past several years. Even though databases are indispensable resources for the scientific community, recent studies have shown that more than 50% of the databases are not regularly updated. In addition, more than 20% of the database links are inactive. To prevent such database and link decay, we have initiated a continuous community annotation project with the active involvement of EV researchers. The EV research community can set a gold standard in data sharing with Vesiclepedia, which could evolve as a primary resource for the field.
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| 4. |
- Kunzmann, Andrea, et al.
(författare)
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Efficient internalization of silica-coated iron oxide nanoparticles of different sizes by primary human macrophages and dendritic cells
- 2011
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Ingår i: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 253:2, s. 81-93
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Tidskriftsartikel (refereegranskat)abstract
- Engineered nanoparticles are being considered for a wide range of biomedical applications, from magnetic resonance imaging to "smart" drug delivery systems. The development of novel nanomaterials for biomedical applications must be accompanied by careful scrutiny of their biocompatibility. In this regard, particular attention should be paid to the possible interactions between nanoparticles and cells of the immune system, our primary defense system against foreign invasion. On the other hand, labeling of immune cells serves as an ideal tool for visualization, diagnosis or treatment of inflammatory processes, which requires the efficient internalization of the nanoparticles into the cells of interest. Here, we compare novel monodispersed silica-coated iron oxide nanoparticles with commercially available dextran-coated iron oxide nanoparticles. The silica-coated iron oxide nanoparticles displayed excellent magnetic properties. Furthermore, they were nontoxic to primary human monocyte-derived macrophages at all doses tested whereas dose-dependent toxicity of the smaller silica-coated nanoparticles (30 nm and 50 nm) was observed for primary monocyte-derived dendritic cells, but not for the similarly small dextran-coated iron oxide nanoparticles. No macrophage or dendritic cell secretion of pro-inflammatory cytokines was observed upon administration of nanoparticles. The silica-coated iron oxide nanoparticles were taken up to a significantly higher degree when compared to the dextran-coated nanoparticles, irrespective of size. Cellular internalization of the silica-coated nanoparticles was through an active, actin cytoskeleton-dependent process. We conclude that these novel silica-coated iron oxide nanoparticles are promising materials for medical imaging, cell tracking and other biomedical applications. (C) 2011 Elsevier Inc. All rights reserved.
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| 5. |
- Kupferschmidt, Natalia, et al.
(författare)
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Mesoporous silica particles potentiate antigen-specific T-cell responses
- 2014
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Ingår i: Nanomedicine. - 1743-5889 .- 1748-6963. ; 9:12, s. 1835-1846
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To study the adjuvant effect of mesoporous silica particles and their capability of modifying an already existing allergic Th2-like immune response. Materials & methods: The adjuvant effect of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica particles was studied in an antigen-specific ovalbumin (OVA) system in vitro and in vivo. The capacity of the OVA-loaded SBA-15 particles (SBA-15-OVA) to modify an existing immune response was assessed in a murine allergy model. Results: SBA-15-OVA induced significantly stronger OVA-specific splenocyte proliferation compared with OVA alone. Significantly higher IFN-gamma production was observed in ex vivo OVA-stimulated splenocytes from SBA-15-OVA-immunized mice compared with mice injected with only SBA-15 or OVA. Treatment of OVA-sensitized mice with SBA-15-OVA modified the immune response with significantly lower serum levels of OVA-specific IgE and higher IgG levels compared with the alum-OVA-treated group. Conclusion: The results are promising for the continued development of mesoporous silica materials for therapeutic applications.
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| 6. |
- Kupferschmidt, Natalia, et al.
(författare)
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Mesoporous silica particles potentiate antigen specific T cell responses
- 2014
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Ingår i: Nanomedicine. - : Future Medicine Ltd. - 1743-5889 .- 1748-6963. ; 9:12, s. 1835-1846
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To study the adjuvant effect of mesoporous silica particles and their capability of modifying an already existing allergic Th2-like immune response. Materials & methods: The adjuvant effect of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica particles was studied in an antigen-specific ovalbumin (OVA) system in vitro and in vivo. The capacity of the OVA-loaded SBA-15 particles (SBA-15-OVA) to modify an existing immune response was assessed in a murine allergy model. Results: SBA-15-OVA induced significantly stronger OVA-specific splenocyte proliferation compared with OVA alone. Significantly higher IFN-γ production was observed in ex vivo OVA-stimulated splenocytes from SBA-15-OVA-immunized mice compared with mice injected with only SBA-15 or OVA. Treatment of OVA-sensitized mice with SBA-15-OVA modified the immune response with significantly lower serum levels of OVA-specific IgE and higher IgG levels compared with the alum-OVA-treated group. Conclusion: The results are promising for the continued development of mesoporous silica materials for therapeutic applications. Original submitted 18 January 2013; Revised submitted 30 August 2013
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| 7. |
- Kupferschmidt, Natalia
(författare)
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Toxicological and Immunomodulatory Properties of Mesoporous Silica Particles : Applications in Life Sciences
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mesoporous silica particles offer great potential benefits as vehicles for drug delivery and in other biomedical applications. They present a high loading capacity due their ordered and size-tuneable pores that allow molecules to be loaded and released. In addition, they offer the possibility to enhance oral bioavailability of drugs with limited aqueous solubility and to protect pH sensitive drugs from the acidic conditions in the stomach on their way to the intestine.The aim of this thesis was to evaluate the biocompatibility and effects of mesoporous silica particles on immunocompetent cells. Subsequently, two potential life sciences applications were investigated: as adjuvants and as weight reduction agents.Adjuvants are used in vaccines in order to enhance the immunological response towards attenuated and poorly immunogenic antigens. Their function can be mediated through dendritic cells which have a central role in the control of adaptive immunity including immunological memory. Our results show that different types of mesoporous silica particles were able to tune the development of T cells both in human cell cultures and in mice. In contrast to the approved adjuvant alum (aluminium salts) which is a specific inducer of Th2-type immune responses, the particles induced more Th1-like responses, which may be desired in vaccines against allergy and intracellular pathogens such as viruses. Particle exposure to macrophages did not affect their cell function which is crucial for tissue homeostasis, wound repair and in prevention of autoimmune responses. Likewise, the cytokine secretion was not affected, which suggest that macrophages would not modulate the immune response towards the particles.Furthermore, mesoporous silica particles were highly tolerated at daily oral administrations of up to 2000 mg/kg doses for some of the materials prepared. Large pore mesoporous silica particles were shown to act as weight and body fat reduction agents without other observable pathological signs when administered in the diet of obese mice.Together; those results are promising for the development of mesoporous silica as drug delivery systems and adjuvants for oral administration of drugs or vaccines. Additionally, large pore mesoporous silica materials are potential agents for the treatment of obesity.
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| 8. |
- Levänen, Bettina, et al.
(författare)
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Altered microRNA profiles in bronchoalveolar lavage fluid exosomes in asthmatic patients.
- 2013
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 131:3, s. 894-903
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Asthma is characterized by increased airway narrowing in response to nonspecific stimuli. The disorder is influenced by both environmental and genetic factors. Exosomes are nanosized vesicles of endosomal origin released from inflammatory and epithelial cells that have been implicated in asthma. In this study we characterized the microRNA (miRNA) content of exosomes in healthy control subjects and patients with mild intermittent asthma both at unprovoked baseline and in response to environmental challenge.OBJECTIVE: To investigate alterations in bronchoalveolar lavage fluid (BALF) exosomal miRNA profiles due to asthma, and following subway air exposure.METHODS: Exosomes were isolated from BALF from healthy control subjects (n = 10) and patients with mild intermittent asthma (n = 10) after subway and control exposures. Exosomal RNA was analyzed by using microarrays containing probes for 894 human miRNAs, and selected findings were validated with quantitative RT-PCR. Results were analyzed by using multivariate modeling.RESULTS: The presence of miRNAs was confirmed in exosomes from BALF of both asthmatic patients and healthy control subjects. Significant differences in BALF exosomal miRNA was detected for 24 miRNAs with a subset of 16 miRNAs, including members of the let-7 and miRNA-200 families, providing robust classification of patients with mild nonsymptomatic asthma from healthy subjects with 72% cross-validated predictive power (Q(2) = 0.72). In contrast, subway exposure did not cause any significant alterations in miRNA profiles.CONCLUSION: These studies demonstrate substantial differences in exosomal miRNA profiles between healthy subjects and patients with unprovoked, mild, stable asthma. These changes might be important in the inflammatory response leading to bronchial hyperresponsiveness and asthma.
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| 9. |
- Lässer, Cecilia, 1981, et al.
(författare)
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Human saliva, plasma and breast milk exosomes contain RNA: uptake by macrophages.
- 2011
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Ingår i: Journal of Translational Medicine. - : Springer Science and Business Media LLC. - 1479-5876. ; 9:9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Exosomes are 30-100 nm membrane vesicles of endocytic origin produced by numerous cells. They can mediate diverse biological functions, including antigen presentation. Exosomes have recently been shown to contain functional RNA, which can be delivered to other cells. Exosomes may thus mediate biological functions either by surface-to-surface interactions with cells, or by the delivery of functional RNA to cells. Our aim was therefore to determine the presence of RNA in exosomes from human saliva, plasma and breast milk and whether these exosomes can be taken up by macrophages. METHOD: Exosomes were purified from human saliva, plasma and breast milk using ultracentrifugation and filtration steps. Exosomes were detected by electron microscopy and examined by flow cytometry. Flow cytometry was performed by capturing the exosomes on anti-MHC class II coated beads, and further stain with anti-CD9, anti-CD63 or anti-CD81. Breast milk exosomes were further analysed for the presence of Hsc70, CD81 and calnexin by Western blot. Total RNA was detected with a Bioanalyzer and mRNA was identified by the synthesis of cDNA using an oligo (dT) primer and analysed with a Bioanalyzer. The uptake of PKH67-labelled saliva and breast milk exosomes by macrophages was examined by measuring fluorescence using flow cytometry and fluorescence microscopy. RESULTS: RNA was detected in exosomes from all three body fluids. A portion of the detected RNA in plasma exosomes was characterised as mRNA. Our result extends the characterisation of exosomes in healthy humans and confirms the presence of RNA in human saliva and plasma exosomes and reports for the first time the presence of RNA in breast milk exosomes. Our results also show that the saliva and breast milk exosomes can be taken up by human macrophages. CONCLUSIONS: Exosomes in saliva, plasma and breast milk all contain RNA, confirming previous findings that exosomes from several sources contain RNA. Furthermore, exosomes are readily taken up by macrophages, supporting the notion that exosomal RNA can be shuttled between cells.
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| 10. |
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