bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue‐specific expression of mast cell granule serine proteinases and their role in inflammation in the lung and gut
Authors: Miller Hugh R. P. , Pemberton Alan D. 
Published: March 2003

SummarySerine proteinases with trypsin‐like (tryptase) and chymotrypsin‐like (chymase) properties are major constituents of mast cell granules. Several tetrameric tryptases with differing specificities have been characterized in humans, but only a single chymase. In other species there are larger families of chymases with distinct and narrow proteolytic specificities. Expression of chymases and tryptases varies between tissues. Human pulmonary and gastrointestinal mast cells express chymase at lower levels than tryptase, whereas rodent and ruminant gastrointestinal mast cells express uniquely mucosa‐specific chymases. Local and systemic release of chymases and tryptases can be quantified by immunoassay, providing highly specific markers of mast cell activation. The expression and constitutive extracellular secretion of the mucosa‐specific chymase, mouse mast cell proteinase‐1 (mMCP‐1), is regulated by transforming growth factor‐β1 (TGF‐β1) in vitro, but it is not clear how the differential expression of chymases and tryptases is regulated in other species. Few native inhibitors have been identified for tryptases but the tetramers dissociate into inactive subunits in the absence of heparin. Chymases are variably inhibited by plasma proteinase inhibitors and by secretory leucocyte protease inhibitor (SLPI) that is expressed in the airways. Tryptases and chymases promote vascular permeability via indirect and possibly direct mechanisms. They contribute to tissue remodelling through selective proteolysis of matrix proteins and through activation of proteinase‐activated receptors and of matrix metalloproteinases. Chymase may modulate vascular tissues through its ability to process angiotensin‐I to angiotensin‐II. Mucosa‐specific chymases promote epithelial permeability and are involved in the immune expulsion of intestinal nematodes. Importantly, granule proteinases released extracellularly contribute to the recruitment of inflammatory cells and may thus be involved in innate responses to infection.
Peroxisome‐proliferator‐activated‐receptor gamma (PPARγ) independent induction of CD36 in THP‐1 monocytes by retinoic acid
Authors: Han Shouwei , Sidell Neil 
Published: March 2003

SummaryRetinoic acid (RA) has been shown to regulate cellular growth and differentiation of a variety of cell types, including cells of the myelomonocytic lineage. We used the monocytic leukaemia cell line THP‐1, which differentiates to macrophages in response to phorbol 12‐myristate 13‐acetate (PMA), to investigate the regulation by RA of genes in the scavenger receptor type B family (CD36) in human monocyte/macrophages. Reverse transcription–polymerase chain reaction and flow cytometry demonstrated that, like PMA and the natural peroxisome‐proliferator‐activated receptor‐γ (PPARγ) ligand 15d‐PGJ2, RA induced CD36 gene expression in these cells. Moreover, RA plus 15d‐PGJ2 further enhanced CD36 protein and mRNA levels over that seen with the RA or PPARγ compounds alone. The PPARγ antagonist GW9662 was shown to block completely PPARγ‐ligand induction of CD36 gene expression, but had little effect on the action of RA. Our data indicated that RXR‐ and RAR‐specific ligands (LG153 and TTNPB, respectively) were each alone able to increase CD36 mRNA and surface protein levels. By using calphostin C, a specific protein kinase C (PKC) inhibitor, we demonstrated that induction of CD36 by PMA, as well as by PPARγ and RXR ligands were dependent upon PKC activation. In contrast, activation of CD36 through the RAR pathway was not affected by inhibition of PKC activity. Taken together, these data demonstrate that RA can up‐regulate CD36 expression in human monocytes/macrophages. This regulation appears to be predominantly mediated through the RAR/RXR pathway of action and, unlike previously described methods of CD36 modulation, is independent of PPARγ and PKC signalling. This study suggests a possible role for RA in physiological processes involving the scavenger receptor function in cells of the monocyte/macrophage lineage.
Regulation of major histocompatibility complex class II synthesis by interleukin‐10
Authors: Morel Anne‐Sophie , Coulton Gary , Londei Marco 
Published: March 2003

SummaryWe have shown previously that interleukin‐10 (IL‐10) blocks the development and T‐cell stimulatory capacity of human monocyte‐derived dendritic cells, without apparently down‐regulating the surface expression of co‐stimulatory molecules or human leucocyte antigen (HLA) molecules. In the majority of donors (60%), the cell surface levels of HLA‐DR actually increased upon IL‐10 treatment. Here we have shown that IL‐10 does not regulate HLA‐DR transcription as assessed by polymerase chain reation. Epifluorescence microscopy analysis showed that IL‐10 primarily increased the intracellular pool of HLA‐DR. In fact, IL‐10 directly increased HLA‐DR protein synthesis. However, IL‐10 did not significantly alter the synthesis of invariant chain (Ii), which plays a crucial role in the assembly, transport and loading of newly formed HLA class II molecules, nor the amount of Ii reaching the cell‐surface. In contrast, IL‐10 increased the amount of HLA‐DR‐bound Iip33 shortly after the HLA‐DR complex assembly. We postulate that, upon IL‐10 treatment, immature Ii‐associated HLA II molecules can still transit to the cell surface as they do in immature dendritic cells and recycle to the intracellular space, where they accumulate. A higher proportion of Ii‐associated HLA‐DR, coupled to increased membrane recycling, may contribute to the lower T‐cell stimulatory capacity of IL‐10‐treated dendritic cells.
Modulation of the CD40–CD40 ligand interaction using human anti‐CD40 single‐chain antibody fragments obtained from the n‐CoDeR phage display library
Authors: Ellmark Peter , Ottosson Camilla , Borrebaeck Carl A. K. , Malmborg Hager Ann‐Christin , Furebring Christina 
Published: March 2003

SummaryCD40 plays a central regulatory role in the immune system and antibodies able to modulate CD40 signalling may consequently have a potential in immunotherapy, in particular for treatment of lymphomas and autoimmune disease like multiple sclerosis. As a first step to achieve this goal, we describe the selection and characterization of a novel set of fully human anti‐CD40 antibody fragments (scFv) from a phage display library (n‐CoDeR). In order to determine their biological potential, these antibody fragments have been analysed for their ability to promote B‐cell activation, rescue from apoptosis and to block the CD40–CD40 ligand (CD40L) interaction. The selected cohort of human scFv could be subcategorized, each expressing a distinct functional signature. Thus scFv were generated that induced B‐cell proliferation, rescued B cells from apoptosis and blocked the CD40–CD40L interaction to different extents. In particular, one of the scFv clones (F33) had the ability to abrogate completely this interaction. The epitope recognition patterns as well as individual rate constants were also determined and the affinity was shown to vary from low to high nanomolar range. In conclusion, this panel of human anti‐CD40 scFv fragments displays a number of distinct properties, which may constitute a valuable source when evaluating candidates for in vivo trials.
Enhancement of neutrophil infiltration in histidine decarboxylase‐deficient mice
Authors: Hirasawa Noriyasu , Ohtsu Hiroshi , Watanabe Takehiko , Ohuchi Kazuo 
Published: March 2003

SummaryThe roles of histamine in the anaphylactic increase in vascular permeability and leucocyte infiltration were analysed in an air pouch‐type allergic inflammation model in histidine decarboxylase‐deficient (HDC−/−) mice and wild‐type mice. In the immunized wild‐type mice, histamine content in the pouch fluid and vascular permeability in the anaphylaxis phase were increased by injection of the antigen solution into the air pouch. However, in the immunized HDC−/− mice, the antigen challenge did not increase histamine content in the pouch fluid and vascular permeability in the anaphylaxis phase. Number of leucocytes (more than 83% are neutrophils) in the pouch fluid 4–24 hr after the antigen challenge in the HDC−/− mice was significantly higher than that in the wild‐type mice. Simultaneous injection of histamine with the antigen solution into the air pouch of the immunized HDC−/− mice reduced the antigen‐induced leucocyte infiltration at 4 hr. Simultaneous injection of the H2 antagonist cimetidine but not the H1 antagonist pyrilamine with the antigen solution into the air pouch of the immunized wild‐type mice further increased leucocyte infiltration at 4 hr. The levels of macrophage inflammatory protein‐2 at 2 hr and of tumour necrosis factor‐α at 4 hr in the pouch fluid of the HDC−/− mice were significantly higher than those of the wild‐type mice. These findings indicate that histamine plays significant roles not only in the anaphylactic increase in vascular permeability via H1 receptors but also in the negative regulation of neutrophil infiltration via H2 receptors in allergic inflammation.
Functional and phenotypic studies of two variants of a human mast cell line with a distinct set of mutations in the c‐kit proto‐oncogene
Authors: Sundström Magnus , Vliagoftis Harissios , Karlberg Peter , Butterfield Joseph H. , Nilsson Kenneth , Metcalfe Dean D. , Nilsson Gunnar 
Published: March 2003

SummaryThe human mast cell line (HMC)‐1 cell line is growth‐factor independent because of a constitutive activity of the receptor tyrosine kinase Kit. Such deregulated Kit activity has also been suggested causative in gastrointestinal stromal tumours (GISTs) and mastocytosis. HMC‐1 is the only established continuously growing human mast cell line and has therefore been widely employed for in vitro studies of human mast cell biology. In this paper we describe two sublines of HMC‐1, named HMC‐1560 and HMC‐1560,816, with different phenotypes and designated by the locations of specific mutations in the c‐kit proto‐oncogene. Activating mutations in the Kit receptor were characterized using the pyrosequencing™ method. Both sublines have a heterozygous T to G mutation at codon 560 in the juxtamembrane region of the c‐kit gene causing an amino acid substitution of Gly‐560 for Val. In contrast, only HMC‐1560,816 cells have the c‐kitV816 mutation found in mast cell neoplasms causing an Asp→Val substitution in the intracellular kinase domain. Kit was constitutively phosphorylated on tyrosine residues and associated with phosphatidylinositol 3′‐kinase (PI 3‐kinase) in both variants of HMC‐1, but this did not lead to a constitutive phosphorylation of Akt or extracellular regulated protein kinase (ERK), which are signalling molecules normally activated by the interaction of stem cell factor (SCF) with Kit. The documentation and characterization of two sublines of HMC‐1 cells provides both information on the biological consequences of mutations in Kit and recognition of the availability of what in reality are two distinct cultured human mast cell lines.
CD1d‐restricted natural killer T cells are potent targets for human immunodeficiency virus infection
Authors: Fleuridor Richardson , Wilson Brian , Hou Runhua , Landay Alan , Kessler Harold , Al‐Harthi Lena 
Published: March 2003

SummaryInvariant human natural killer T cells (NKT) express a restricted T‐cell receptor (TCR) Vα24Vβ11 repertoire. These cells share both phenotypic and functional similarities between NK and T cells. Given the emerging role of NKT cells as critical cells in bridging the gap between innate and adaptive immunity, we examined their susceptibility to productive human immunodeficiency virus (HIV) infection by T‐tropic, M‐tropic, and primary isolates of HIV. We generated three human NKT cell clones (CA5, CA29, and CA31). Phenotypic characterization of these Vα24+ Vβ11+ clones indicated that they were predominately positive for CD4, CD161, HLA‐DR, CD38, CD45RO, and CD95 expression. The NKT cell clones expressed significantly more surface CCR5 molecules/cell and lower CXCR4 molecules/cell than phytohaemagglutinin‐stimulated peripheral blood mononuclear cells (PBMC). Consistent with the surface expression of CCR5 and CXCR4, the NKT clones were also selectively susceptible to HIV M‐tropic, T‐tropic, and primary isolate infection, as evaluated by both HIV p24 enzyme‐linked immunosorbent assay and intracellular staining of HIV proteins. The amount of p24 production was dependent on the NKT clone studied and the HIV strain used. Clones CA29 and CA31 were also susceptible to HIV IIIB infection. The virions produced by these clones were able to productively infect PHA‐stimulated PBMCs with the same kinetics as for primary infection of CD4+ blast. Collectively, this data demonstrates that NKT cells can be a target for productive HIV infection but with a lag in the time to peak p24 production.
Structure of Hermes integrations in the germline of the yellow fever mosquito, Aedes aegypti
Authors: Jasinskiene N. , Coates C. J. , James A. A. 
Published: March 2003

AbstractThe Hermes transposable element is derived from the house fly, Musca domestica, and can incorporate into the germline of the yellow fever mosquito, Aedes aegypti. Preliminary Southern analyses indicated that Hermes integrated along with the marker gene into the mosquito genomic DNA. Here we show that Hermes integrations are accompanied by the integration of the donor plasmid as well. In addition, breaks in the donor plasmid DNAs do not occur precisely, or at the end of the terminal inverted repeats, and are accompanied by small deletions in the plasmids. Furthermore, integrations do not cause the typical 8‐bp duplications of the target site DNA. No integrations are observed in the absence of a source of Hermes transposase. The Hermes transposase clearly did not catalyse precise cut‐and‐paste transposition in these transformed lines. It may have integrated the transposon through general recombination or through a partial replicative transposition mechanism. The imprecision of Hermes integration may result from interactions of the transposase with an endogenous hAT‐like element in the mosquito genome.
The mitochondrial genome of the Mediterranean fruit fly, Ceratitis capitata
Authors: Spanos L. , Koutroumbas G. , Kotsyfakis M. , Louis C. 
Published: March 2003

AbstractThe complete sequence of the mitochondrial genome of Ceratitis capitata has been determined. The circular genome is 15 980 bp long and contains a standard gene complement, i.e. the large and small ribosomal RNA subunits, twenty‐two transfer RNA (tRNA) genes and thirteen genes encoding mitochondrial proteins. When comparing the sequence to fragments previously sequenced from other isolates it becomes apparent that interstrain polymorphisms are not rare. These differences are potentially useful for the development of diagnostic tools for population analysis applications, such as determining the source of recent introductions. Moreover, they could help obtain a solution to the long‐lasting controversy on the possible eradication of the Medfly from certain locations.
Two opsin genes from the vetch aphid, Megoura viciae
Authors: Gao N. , Foster R. G. , Hardie J. 
Published: March 2003

AbstractThe cDNAs of two opsins (Megopsin1 and Megopsin2) from the vetch aphid, Megoura viciae, have been sequenced and encoded for gene products with 378 and 371 amino acid residues, respectively. Phylogenetic analysis reveals that Megopsin1 falls into the insect long‐wavelength opsin group and Megopsin2 is a member of the insect UV‐wavelength opsins. Both opsins share the key features of G‐protein‐coupled receptors and the specific motifs of photopigments. In situ hybridization demonstrated that the transcripts of Megopsin1 and Megopsin2 were expressed in the retinula cells of the compound eyes.
Identification of a point mutation in the voltage‐gated sodium channel gene of Kenyan Anopheles gambiae associated with resistance to DDT and pyrethroids
Authors: Ranson H. , Jensen B. , Vulule J. M. , Wang X. , Hemingway J. , Collins F. H. 
Published: March 2003

AbstractA field trial of permethrin‐impregnated bednets and curtains was initiated in Western Kenya in 1990, and a strain of Anopheles gambiae showing reduced susceptibility to permethrin was colonized from this site in 1992. A leucine–phenylalanine substitution at position 1014 of the voltage‐gated sodium channel is associated with resistance to permethrin and DDT in many insect species, including Anopheles gambiae from West Africa. We cloned and sequenced a partial sodium channel cDNA from the Kenyan permethrin‐resistant strain and we identified an alternative substitution (leucine to serine) at the same position, which is linked to the inheritance of permethrin resistance in the F2 progeny of genetic crosses between susceptible and resistant individuals. The diagnostic polymerase chain reaction (PCR) developed by
Martinez‐Torres et al. [(1998) Insect Mol Biol 7: 179–184] to detect kdr alleles in field populations of An. gambiae will not detect the Kenyan allele and hence reliance on this assay may lead to an underestimate of the prevalence of pyrethroid resistance in this species. We adapted the diagnostic PCR to detect the leucine–serine mutation and with this diagnostic we were able to demonstrate that this kdr allele was present in individuals collected from the Kenyan trial site in 1986, prior to the introduction of pyrethroid‐impregnated bednets. The An. gambiae sodium channel was physically mapped to chromosome 2L, division 20C. This position corresponds to the location of a major quantitative trait locus determining resistance to permethrin in the Kenyan strain of An. gambiae.
Identification of the sibling species of the Anopheles maculipennis complex by heteroduplex analysis
Authors: Romi R. , Boccolini D. , Di Luca M. , La Rosa G. , Marinucci M. 
Published: March 2003

AbstractThe group of anopheline mosquitoes referred to as ‘Anopheles maculipennis complex’ includes the most important malaria vectors of the Palearctic Western region. The species belonging to this complex, however, are difficult or impossible to distinguish by morphological characters. To differentiate sibling palearctic species belonging to this complex, interspecific differences in the ITS2 sequences were used to set up a rapid and sensitive diagnostic tool based on heteroduplex analysis. The relative heteroduplex mobility allowed the following seven species to be readily distinguished: An. atroparvus, An. labranchiae, An. maculipennis s.s., An. martinius, An melanoon, An. messeae and An. sacharovi.
Differential regulation of ribosomal protein gene expression in Aedesaegypti mosquitoes before and after the blood meal
Authors: Niu L. L. , Fallon A. M. 
Published: March 2003

AbstractIn fat body of the mosquito, Aedesaegypti, a cycle of ribosome accumulation and degradation accompanies synthesis of the yolk protein precursor, vitellogenin. Here we compare the transcription and translation of ribosomal proteins rpS6, rpL8 and rpL34, relative to rRNA and vitellogenin genes in Aedesaegypti fat body after eclosion, and in response to a blood meal. Analysis using Northern blots and reverse‐transcription polymerase chain reactions (RT‐PCR) showed that the rpS6, rpL8 and rpL34 genes are coordinately regulated with respect to one another, and that ribosomal protein gene expression in this system was predominantly regulated by transcription during the 3–4 days between adult eclosion and blood feeding. After a blood meal, ribosomal protein mRNA levels remained similar to those in unfed females during the first 18 h, then declined to minimum levels by 48 h after the blood meal. These data indicate that transcription of ribosomal protein genes is low in vitellogenic mosquitoes, relative to previtellogenic females. Experiments with the dissected fat body, however, showed that levels of acetic acid‐soluble proteins increased by approximately threefold between 12 and 24 h after the blood meal. Taken together, these observations suggest that the active translation of ribosomal proteins from stable mRNA accompanies ribosome biosynthesis after the blood meal. Thus, in the fat body of adult female mosquitoes, the expression of ribosomal protein genes is regulated at the level of transcription before the blood meal, while translational control is the predominant regulatory mechanism after the blood meal.
Sequence and organization of the mitochondrial genome of the Chagas disease vector, Triatoma dimidiata
Authors: Dotson E. M. , Beard C. B. 
Published: March 2003

AbstractThe 17 019 bp mitochondrial genome of Triatoma dimidiata is composed of thirteen protein coding sequences, twenty‐two tRNAs, small and large ribosomal units, and a control region. The gene order and orientation are identical to that of Drosophila yakuba. The nucleotide composition is biased toward adenine and thymine (69.5% A + T). The 2.1 kb putative control region, known as the A + T rich region in most insects, has an A + T bias of 66%, but contains a 400 bp sequence that is 77.5% A + T and two other distinct regions: (1) one with a lower A + T bias (60.1%) and (2) a region of eight tandem repeat units.The identified 1.4 kb nuclear copy of mitochondrial sequences encompasses the string of Gs and the beginning of the cytochrome c oxidase 1 gene but lacks the 1.8 kb region spanning the eight tandem repeats and the 5′ end of the NADH dehydrogenase subunit II gene.
Sindbis virus‐induced silencing of dengue viruses in mosquitoes
Authors: Adelman Z. N. , Blair C. D. , Carlson J. O. , Beaty B. J. , Olson K. E. 
Published: March 2003

AbstractAedes aegypti were injected intrathoracically with double subgenomic Sindbis (dsSIN) viruses with inserted sequences derived from the genome of one or more of the four dengue (DEN) virus serotypes. Mosquitoes were highly resistant to challenge with homologous DEN viruses from which the effector sequences were derived, and resistance to DEN viruses was independent of the orientation of the effector RNA. dsSIN viruses designed to express RNA derived from the premembrane coding region of DEN‐2 prevented the accumulation of DEN2 RNA, and C6/36 cells were highly resistant to DEN‐2 virus when challenged at 2, 5 or 8 days after the initial dsSIN virus infections, even though the dsSIN‐derived RNA had sharply declined at the later time points. Initiation of resistance occurred prior to or within the first 8 h after challenge with DEN‐2 virus. We conclude that DEN viruses are inhibited by a mechanism similar to post‐transcriptional gene silencing (PTGS) or RNA interference (RNAi) phenomena described in plants and invertebrates, respectively. The potential occurrence of PTGS or RNAi in mosquitoes and mosquito cells suggests new ways of inhibiting the replication of arthropod‐borne viruses in mosquito vectors, studying vector–virus interactions, and silencing endogenous mosquito genes.