| 1. |
- Agrawal, Smriti, et al.
(författare)
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Dystroglycan is selectively cleaved at the parenchymal basement membrane at sites of leukocyte extravasation in experimental autoimmune encephalomyelitis.
- 2006
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 203:4, s. 1007-1019
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Tidskriftsartikel (refereegranskat)abstract
- The endothelial cell monolayer of cerebral vessels and its basement membrane (BM) are ensheathed by the astrocyte endfeet, the leptomeningeal cells, and their associated parenchymal BM, all of which contribute to establishment of the blood–brain barrier (BBB). As a consequence of this unique structure, leukocyte penetration of cerebral vessels is a multistep event. In mouse experimental autoimmune encephalomyelitis (EAE), a widely used central nervous system inflammatory model, leukocytes first penetrate the endothelial cell monolayer and underlying BM using integrin β1-mediated processes, but mechanisms used to penetrate the second barrier defined by the parenchymal BM and glia limitans remain uninvestigated. We show here that macrophage-derived gelatinase (matrix metalloproteinase [MMP]-2 and MMP-9) activity is crucial for leukocyte penetration of the parenchymal BM. Dystroglycan, a transmembrane receptor that anchors astrocyte endfeet to the parenchymal BM via high affinity interactions with laminins 1 and 2, perlecan and agrin, is identified as a specific substrate of MMP-2 and MMP-9. Ablation of both MMP-2 and MMP-9 in double knockout mice confers resistance to EAE by inhibiting dystroglycan cleavage and preventing leukocyte infiltration. This is the first description of selective in situ proteolytic damage of a BBB-specific molecule at sites of leukocyte infiltration.
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| 2. |
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| 3. |
- Björk, Per, et al.
(författare)
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Identification of human S100A9 as a novel target for treatment of autoimmune disease via binding to quinoline-3-carboxamides.
- 2009
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Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1545-7885. ; 7:4, s. 800-812
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Tidskriftsartikel (refereegranskat)abstract
- Despite more than 25 years of research, the molecular targets of quinoline-3-carboxamides have been elusive although these compounds are currently in Phase II and III development for treatment of autoimmune/inflammatory diseases in humans. Using photoaffinity cross-linking of a radioactively labelled quinoline-3-carboxamide compound, we could determine a direct association between human S100A9 and quinoline-3-carboxamides. This interaction was strictly dependent on both Zn++ and Ca++. We also show that S100A9 in the presence of Zn++ and Ca++ is an efficient ligand of receptor for advanced glycation end products (RAGE) and also an endogenous Toll ligand in that it shows a highly specific interaction with TLR4/MD2. Both these interactions are inhibited by quinoline-3-carboxamides. A clear structure-activity relationship (SAR) emerged with regard to the binding of quinoline-3-carboxamides to S100A9, as well as these compounds potency to inhibit interactions with RAGE or TLR4/MD2. The same SAR was observed when the compound's ability to inhibit acute experimental autoimmune encephalomyelitis in mice in vivo was analysed. Quinoline-3-carboxamides would also inhibit TNFalpha release in a S100A9-dependent model in vivo, as would antibodies raised against the quinoline-3-carboxamide-binding domain of S100A9. Thus, S100A9 appears to be a focal molecule in the control of autoimmune disease via its interactions with proinflammatory mediators. The specific binding of quinoline-3-carboxamides to S100A9 explains the immunomodulatory activity of this class of compounds and defines S100A9 as a novel target for treatment of human autoimmune diseases.
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| 4. |
- Björkman, Per, et al.
(författare)
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Common Interactions between S100A4 and S100A9 Defined by a Novel Chemical Probe.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- S100A4 and S100A9 proteins have been described as playing roles in the control of tumor growth and metastasis. We show here that a chemical probe, oxyclozanide (OX), selected for inhibiting the interaction between S100A9 and the receptor for advanced glycation end-products (RAGE) interacts with both S100A9 and S100A4. Furthermore, we show that S100A9 and S100A4 interact with RAGE and TLR4; interactions that can be inhibited by OX. Hence, S100A4 and S100A9 display similar functional elements despite their primary sequence diversity. This was further confirmed by showing that S100A4 and S100A9 dimerize both in vitro and in vivo. All of these interactions required levels of Zn(++) that are found in the extracellular space but not intracellularly. Interestingly, S100A4 and S100A9 are expressed by distinct CD11b(+) subpopulations both in healthy animals and in animals with either inflammatory disease or tumor burden. The functions of S100A9 and S100A4 described in this paper, including heterodimerization, may therefore reflect S100A9 and S100A4 that are released into the extra-cellular milieu.
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| 5. |
- Brännström, Kristoffer, 1974-
(författare)
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Molecular dissection of established and proposed members of the Op18/Stathmin family of tubulin binding proteins
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- My initial aim was a functional analysis of the conserved Op18/stathmin family of microtubule-regulators, which includes the ubiquitous cytosolic Op18 protein and the neural membrane-attached RB3 and SCG10 proteins. The solved X-ray structure has shown that these proteins form a complex with tubulin -heterodimers via two imperfect helical repeats, which result in two head-to-tail aligned heterodimers in a tandem-tubulin complex. We have analyzed GTP exchange and GTP hydrolysis at the two exchangeable GTP-binding sites (E-site) within the tandem-tubulin complex. A comparison of Op18, RB3 and SCG10 proteins indicates that Op18/Stathmin family proteins have evolved to maintain the two heterodimers in a configuration that restrains the otherwise potent GTPase productive interactions facilitated by the head-to-head alignment of heterodimers in protofilaments. We concluded from these studies that tubulin heterodimers in complex with Op18/stathmin family members are subject to allosteric effects that prevent futile cycles of GTP hydrolysis. To understand the significance of the large differences in tubulin affinity of Op18, RB3 and SCG10, we have fused each of the heterodimer-binding regions of these three proteins with the CD2 cell-surface protein to generate confined plasma membrane localization of the resulting CD2 chimeras. We showed that, in contrast to CD2-Op18, both the CD2-SCG10 and CD2-RB3 chimeras sequester tubulin at the plasma membrane, which results in >35% reduction of cytosolic tubulin heterodimer levels. However, all three CD2-chimeras, including the tubulin sequestration-incompetent CD2-Op18, destabilize interphase microtubules. Given that microtubules are in extensive contact with the plasma membrane during the interphase, these findings indicate that Op18-like proteins have the potential to destabilize microtubules by both sequestration and direct interaction with microtubules. Sm16/SmSLP (Stathmin-Like Protein) has been identified as a protein released during skin penetration of the Schistosoma mansoni parasite. This protein has been ascribed both anti-inflammatory activities and a functional similarity with the conserved cytosolic tubulin-binding protein stathmin/Op18. However, our studies refuted any functional similarity with stathmin/Op18 and we found instead that Sm16/SmSLP is a lipid bilayer binding protein that is taken up by cells through endocytosis. To study immuno-modulatory properties of Sm16/SmSLP, we designed an engineered version with decreased aggregation propensity, thus facilitating expression and purification of a soluble Sm16 /SmSLP protein from the eukaryotic organism Pichia pastoris. Determination of the hydrodynamic parameters revealed that both the recombinant and native Sm16/SmSLP is a ~9-subunits oligomer. The recombinant protein was found to have no effect on T lymphocyte activation, cell proliferation or the basal level of cytokine production of whole human blood or monocytic cells. Interestingly, however, recombinant Sm16 was found to potently inhibit the cytokine response to the Toll-like receptor (TLR) ligands lipopolysaccharide (LPS) and Poly(I:C). Since Sm16 specifically inhibits degradation of the IRAK1 signaling protein in LPS stimulated monocytes, it seems likely that inhibition is exerted proximal to the TLR-complex.
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| 6. |
- Chakraborty, Paramita, et al.
(författare)
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Vesicular Location and Transport of S100A8 and S100A9 Proteins in Monocytoid Cells.
- 2015
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- We show here, by using surface biotinylation, followed by Western blotting or surface plasmon resonance analysis, that very low levels of S100A8 and/or S100A9 can be detected on the surface of THP-1 cells or freshly isolated human monocytes. This was supported by immune-electron microscopy where we observed membrane-associated expression of the proteins restricted to small patches. By using confocal microscopy we could determine that S100A8 and S100A9 protein in THP-1 cells or freshly isolated human monocytes was mostly present in vesicular structures. This finding was confirmed using immune-electron microscopy. Subcellular fractionation and confocal microscopy showed that these vesicular structures are mainly early endosomes and endolysosomes. Our subsequent studies showed that accumulation of S100A8 and S100A9 in the endolysosomal compartment is associated with induction of their release from the cells. Furthermore, an inhibitor of lysosomal activity could modulate the release of S100A8 and S100A9 in the extracellular milieu. Our current results suggest that the S100A8 and S100A9 proteins are primarily associated with certain kinds of cytosolic vesicles and may be secreted via an endolysosomal pathway.
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| 7. |
- Deronic, Adnan, et al.
(författare)
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The anti-tumor effect of the quinoline-3-carboxamide tasquinimod : Blockade of recruitment of CD11b+ Ly6Chi cells to tumor tissue reduces tumor growth
- 2016
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous work has demonstrated immunomodulatory, anti-tumor, anti-metastatic and anti-angiogenic effects of the small molecule quinoline-3-carboxamide tasquinimod in pre-clinical cancer models. To better understand the anti-tumor effects of tasquinimod in transplantable tumor models, we have evaluated the impact of the compound both on recruitment of myeloid cells to tumor tissue and on tumor-induced myeloid cell expansion as these cells are known to promote tumor development. Methods: Mice bearing subcutaneous 4 T1 mammary carcinoma tumors were treated with tasquinimod in the drinking water. A BrdU-based flow cytometry assay was utilized to assess the impact of short-term tasquinimod treatment on myeloid cell recruitment to tumors. Additionally, long-term treatment was performed to study the anti-tumor effect of tasquinimod as well as its effects on splenic myeloid cells and their progenitors. Myeloid cell populations were also immune-depleted by in vivo antibody treatment. Results: Short-term tasquinimod treatment did not influence the proliferation of splenic Ly6Chi and Ly6Ghi cells, but instead reduced the influx of Ly6Chi cells to the tumor. Treatment with tasquinimod for various periods of time after tumor inoculation revealed that the anti-tumor effect of this compound mainly operated during the first few days of tumor growth. Similar to tasquinimod treatment, antibody-mediated depletion of Ly6Chi cells within that same time frame, caused reduced tumor growth, thereby confirming a significant role for these cells in tumor development. Additionally, long-term tasquinimod treatment reduced the splenomegaly and expansion of splenic myeloid cells during a later phase of tumor development. In this phase, tasquinimod normalized the tumor-induced alterations in myeloerythroid progenitor cells in the spleen but had only limited impact on the same populations in the bone marrow. Conclusions: Our results indicate that tasquinimod treatment reduces tumor growth by operating early after tumor inoculation and that this effect is at least partially caused by reduced recruitment of Ly6Chi cells to tumor tissue. Long-term treatment also reduces the number of splenic myeloid cells and myeloerythroid progenitors, but these effects did not influence established rapidly growing tumors.
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| 8. |
- Deronic, Adnan, et al.
(författare)
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The quinoline-3-carboxamide paquinimod (ABR-215757) reduces leukocyte recruitment during sterile inflammation: Leukocyte- and context-specific effects.
- 2014
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Ingår i: International Immunopharmacology. - : Elsevier BV. - 1878-1705 .- 1567-5769. ; 18:2, s. 290-297
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Tidskriftsartikel (refereegranskat)abstract
- Quinoline-3-carboxamides (Q-compounds) are currently in clinical development for both autoimmune disease and cancer. We have previously shown that the Q-compound paquinimod (ABR-215757) significantly ameliorates disease symptoms in several mouse models of human inflammatory disease. Considering that recruitment of inflammatory cells into tissue is a common denominator of these models, we have in this report investigated whether paquinimod would interfere with cell accumulation during sterile peritoneal inflammation. To mimic the cell recruitment elicited by tissue injury, we used necrotic cells to induce the acute inflammatory response. We show that per oral treatment with paquinimod significantly reduced the accumulation of Ly6C(hi) inflammatory monocytes and eosinophils, but not neutrophils, in this model, and that this correlated with reduced number of such cells also in the omentum. Treatment also reduced the accumulation of these cell populations at a subcutaneous site of inflammation. In alum-induced inflammation, however, neutrophils were the dominant cell population and paquinimod failed to reduce the accumulation of inflammatory cells. Taken together, our results indicate that paquinimod selectively inhibits cell recruitment during acute sterile inflammation, but that this effect is context-dependent. These data have important implications for the understanding of the mechanism of action of Q-compounds in both pre-clinical and clinical settings.
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| 9. |
- Egorova, Olga, et al.
(författare)
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Maternal blood folate status during early pregnancy and occurrence of autism spectrum disorder in offspring: a study of 62 serum biomarkers
- 2020
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Ingår i: Molecular Autism. - : BioMed Central. - 2040-2392. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Autism spectrum disorder (ASD) evolves from an interplay between genetic and environmental factors during prenatal development. Since identifying maternal biomarkers associated with ASD risk in offspring during early pregnancy might result in new strategies for intervention, we investigated maternal metabolic biomarkers in relation to occurrence of ASD in offspring using both univariate logistic regression and multivariate network analysis.Methods: Serum samples from 100 women with an offspring diagnosed with ASD and 100 matched control women with typically developing offspring were collected at week 14 of pregnancy. Concentrations of 62 metabolic biomarkers were determined, including amino acids, vitamins (A, B, D, E, and K), and biomarkers related to folate (vitamin B9) metabolism, lifestyle factors, as well as C-reactive protein (CRP), the kynurenine-tryptophan ratio (KTR), and neopterin as markers of inflammation and immune activation.Results: We found weak evidence for a positive association between higher maternal serum concentrations of folate and increased occurrence of ASD (OR per 1 SD increase: 1.70, 95% CI 1.22–2.37, FDR adjusted P = 0.07). Multivariate network analysis confirmed expected internal biochemical relations between the biomarkers. Neither inflammation markers nor vitamin D3 levels, all hypothesized to be involved in ASD etiology, displayed associations with ASD occurrence in the offspring.Conclusions: Our findings suggest that high maternal serum folate status during early pregnancy may be associated with the occurrence of ASD in offspring. No inference about physiological mechanisms behind this observation can be made at the present time because blood folate levels may have complex relations with nutritional intake, the cellular folate status and status of other B-vitamins. Therefore, further investigations, which may clarify the potential role and mechanisms of maternal blood folate status in ASD risk and the interplay with other potential risk factors, in larger materials are warranted.
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| 10. |
- Ekholm Pettersson, Frida
(författare)
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T-cell Differentiation and Immunological Homeostasis in Lymphopenic and Kappa Light Chain Deficient Mice
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- T lymphocytes are primarily involved in adaptive, cell-mediated, immune reactions. In this thesis T cells were studied regarding central and peripheral differentiation and homeostatic mechanisms for maintanance of the immune repertoire.The influence by mature T cells on thymic development was studied in C.B-17 scid/scid (SCID) mice, devoid of mature T and B cells, and whose thymocyte development is arrested at the early pro-T cell stage. When mature syngeneic T cells were injected the developmental block was overcome and there was an accumulation of CD4+CD8+ thymocytes. This event was accompanied by the maturation of medullary epithelial cells in thymus which seemed to be driven by CD8+ T cells. In the periphery there was initially a spontaneous T-cell proliferation and later, the majority of the donor T lymphocytes showed a memory phenotype with high expression of CD44 and with an early onset of proliferation and cytokine production upon stimulation. This stable pool of memory type of cells sustained for more than a year following treatment.Treating SCID mice with allogeneic T cells results in graft-versus-host disease (GVHD). Severe GVHD was dependent on the MHC-haplotype of the donor cells and was accompanied by profound alterations of the TCR-Vβ repertoire and with high production of IFN-γ.Kappa light chain (κ)-deficient mice have only half the number of B cells as their normal counterparts but normal levels of immunoglobulins. When T cells from κ-deficient mice were stimulated in vitro there was a bias towards production of B-cell stimulatory type 2 cytokines. This is proposed as a mechanism for the homeostatic control of serum immunoglobulin levels in κ-deficient mice.
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