Additional homology searches of all Jackson laboratory murine databases 13, using human S100A12 as the query, were futile. ...a region homologous to the first exon of S100A12 is also present on the ...corresponding chromosome 2 of rat, however, exons 2 and 3 are again missing, suggesting that the S100A12 gene might be damaged in all rodents. ...several proinflammatory properties of this protein might be caused by its binding to RAGE 3. ...the RAGE-S100A12 interaction represents an attractive model to explain how RAGE and its proinflammatory ligand contribute to the pathophysiology of several inflammatory diseases 1,3.
Mechanisms linking innate immunity and autoimmune responses are poorly understood (1). Myeloid-related protein-8 (Mrp8) and Mrp14 are damage-associated molecular pattern molecules (DAMPs) highly ...upregulated in various autoimmune disorders. We show in a mouse autoimmune model that local Mrp8 and Mrp14 production is essential for the induction of autoreactive CD8.sup.+ T cells and the development of systemic autoimmunity. This effect is mediated via Toll-like receptor 4 (TLR4) signaling leading to increased interleukin-17 (IL-17) expression. Notably, expression of Mrp8 and Mrp14 was upregulated in cutaneous lupus erythematosus, and stimulation of CD8.sup.+ T cells from individuals with lupus erythematosus with MRP proteins resulted in an upregulation of IL-17, suggesting a key role for MRP8 and MRP14 for the development of autoreactive lymphocytes during human autoimmunity as well. These results demonstrate a link between local expression of DAMP molecules and the development of systemic autoimmunity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Mechanisms linking innate immunity and autoimmune responses are poorly understood. Myeloid-related protein-8 (Mrp8) and Mrp14 are damage-associated molecular pattern molecules (DAMPs) highly ...upregulated in various autoimmune disorders. We show in a mouse autoimmune model that local Mrp8 and Mrp14 production is essential for the induction of autoreactive CD8 super(+) T cells and the development of systemic autoimmunity. This effect is mediated via Toll-like receptor 4 (TLR4) signaling leading to increased interleukin-17 (IL-17) expression. Notably, expression of Mrp8 and Mrp14 was upregulated in cutaneous lupus erythematosus, and stimulation of CD8 super(+) T cells from individuals with lupus erythematosus with MRP proteins resulted in an upregulation of IL-17, suggesting a key role for MRP8 and MRP14 for the development of autoreactive lymphocytes during human autoimmunity as well. These results demonstrate a link between local expression of DAMP molecules and the development of systemic autoimmunity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Homeotic mutants have been useful for the study of animal development. Such mutants are also known in plants. The isolation and molecular analysis of several homeotic genes in Antirrhinum majus ...provide insights into the underlying molecular regulatory mechanisms of flower development. A model is presented of how the characteristic sequential pattern of developing organs, comprising the flower, is established in the process of morphogenesis
Analysis of the calcium-induced arachidonic acid (AA) binding to S100A8/A9 revealed that maximal AA binding was achieved at molar ratios of 1 mol S100A8 and 1 mol S100A9 and for values greater than 3 ...calciums per EF-hand. The AA binding capacity was not induced by the binding of other bivalent cations, such as Zn
2+, Cu
2+, and Mg
2+, to the protein complex. In contrast, the binding of AA was prevented by the addition of either Zn
2+ or Cu
2+ in the presence of calcium, whereas Mg
2+ failed to abrogate the AA binding capacity. The inhibitory effect was not due to blocking the formation of S100A8/A9 as demonstrated by a protein-protein interaction assay. Fluorescence measurements gave evidence that both Zn
2+ and Cu
2+ induce different conformational changes thereby affecting the calcium-induced formation of the AA binding pocket within the protein complex. Due to the fact that the inhibitory effect of Zn
2+ was present at physiological serum concentrations, it is assumed that released S100A8/A9 may carry AA at inflammatory lesions, but not within the blood compartment.
Neutrophils are the first line of defense at the site of an infection. They encounter and kill microbes intracellularly upon phagocytosis or extracellularly by degranulation of antimicrobial proteins ...and the release of Neutrophil Extracellular Traps (NETs). NETs were shown to ensnare and kill microbes. However, their complete protein composition and the antimicrobial mechanism are not well understood. Using a proteomic approach, we identified 24 NET-associated proteins. Quantitative analysis of these proteins and high resolution electron microscopy showed that NETs consist of modified nucleosomes and a stringent selection of other proteins. In contrast to previous results, we found several NET proteins that are cytoplasmic in unstimulated neutrophils. We demonstrated that of those proteins, the antimicrobial heterodimer calprotectin is released in NETs as the major antifungal component. Absence of calprotectin in NETs resulted in complete loss of antifungal activity in vitro. Analysis of three different Candida albicans in vivo infection models indicated that NET formation is a hitherto unrecognized route of calprotectin release. By comparing wild-type and calprotectin-deficient animals we found that calprotectin is crucial for the clearance of infection. Taken together, the present investigations confirmed the antifungal activity of calprotectin in vitro and, moreover, demonstrated that it contributes to effective host defense against C. albicans in vivo. We showed for the first time that a proportion of calprotectin is bound to NETs in vitro and in vivo.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present the genomic structure of Tam1, a transposable element from Antirrhinum majus. The Tam1 element is 15.2 kb long and includes two genes that are transcribed to produce a 2.4 kb (tnp1) and a ...5 kb mRNA (tnp2). These transcripts partially overlap and the exons are scattered over the whole element. Tnp1 encodes a 53 kDa protein as deduced from the cDNA sequence. The 5 kb transcript of tnp2 contains an open reading frame that shares 45% homology with part of the tnpD gene of En/Spm from maize and 48% homology with an open reading frame of the Tgm element from Glycine max. We discuss the possible functions of these genes by analogy with En/Spm. Additionally, a number of flanking sequences of Tam1 insertions were analysed to investigate the sequence specificity of insertion. From these studies we conclude that Tam1 transposes predominantly into AT-rich regions that can be unique as well as repetitive. No specific target sequence of insertion could be found.
The calcium- and arachidonic acid (AA)-binding proteins S100A8 and S100A9 are involved in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation in phagocytes. They are specifically ...expressed in myeloid cells, and are also found in epithelial cells in various (patho)physiological conditions. We have investigated the consequences of S100A8/A9 overexpression in epithelial cell lines on reactive oxygen species (ROS) generation and downstream signaling. Epithelial carcinoma HeLa cells, which exclusively express Nox2, showed dramatically increased activation of NADPH oxidase by phorbol 12-myristate 13-acetate after S100A8/A9 gene transfection. HaCaT keratinocytes overexpressing S100A8/A9 showed enhanced, transient ROS generation in response to the calcium ionophore A23187 compared to mock-transfected cells. Polymerase chain reaction analysis revealed mRNA transcripts for Nox1, Nox2, and Nox5 in HaCaT keratinocytes. Detailed transfection studies confirmed that NADPH oxidase activities in Nox1- and Nox5-transfected HeLa cells were enhanced after S100A8/A9 gene complementation. Furthermore, mutational analysis revealed that AA binding and Thr113 phosphorylation are important for S100A8/A9-enhanced activation of NADPH oxidase. Nuclear factor-kappaB (NF-kappaB) activation and interleukin-8 mRNA levels were increased in S100A8/A9-HaCaT keratinocytes, consistent with the view that NF-kappaB is a redox-sensitive transcription factor. Because they are expressed in epithelia under specific conditions, S100A8 and S100A9 might be involved in skin pathogenesis by modulating aspects of downstream signaling.
Abstract
Abnormal differentiation of dendritic cell (DC) is a critical factor contributing into ineffective immune response in cancer. We have searched for the genes that could be involved into ...tumor-induced defects in DC differentiation and found that tumor-derived factors consistently up-regulated expression of myeloid related protein 14 (MRP14) and its partner MRP8 in hematopoietic progenitor and myeloid cells during DC differentiation. Normal DC differentiation was associated with dramatic down-regulation of MRP14/8, whereas accumulation of immature myeloid cells was associated with persistently high levels of these proteins. Overexpression of these proteins in embryonic stem cells resulted in inhibition of DC differentiation and accumulation of immature myeloid cells able to form myeloid colonies. It is known that Gr-1+ myeloid-derived suppressor cells (MDSC) frequently accumulate in tumor-bearing mice and during in vitro DC differentiation in the presence of tumor-derived factors. We have found that in tumor-bearing mice MRP14/8 were exclusively accumulated in MDSC. Accumulation of these proteins was controlled by up-regulation of STAT3. MRP14/8 knockout mice had normal level of DCs or MDSC suggesting that MRP proteins were not required for accumulation of MDSC in cancer. Thus, this study demonstrates that tumor-induced up-regulation of MRPs inhibits DC differentiation, which may suggest a novel molecular mechanism of tumor-induced abnormalities in myeloid cells in cancer.
Viral double-stranded RNA (dsRNA) and its synthetic analog poly (I:C) are recognized via multiple pathways and induce the expression of genes related to inflammation. In the present study, we ...demonstrate that poly (I:C) specifically induced the expression of matrix metallo-proteinase-9 (MMP-9) in HaCaT keratinocytes. Studies using specific pharmacological inhibitors revealed the involvement of NF-κB, p38 MAPK, and PI-3K signal transduction pathways in poly (I:C)-induced MMP-9 gene expression. MMP-9 gene induction was sensitive toward treatment with the macrolide antibiotic bafilomycin A1, a vacuolar H(+)-ATPase inhibitor, and with the lysosomotropic agent chloroquine. However, cycloheximide treatment only partially blocked poly (I:C)-induced MMP-9 gene expression. Although HaCaT keratinocytes produce a number of cytokines and chemokines in response to poly (I:C), stimulation experiments revealed that exclusively TNFα strongly promoted MMP-9 gene expression. During the antiviral response MMP-9 expression may be of importance for the tissue injury phase.
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