Adhesion molecule expression by epidermal Langerhans cells and lymph node dendritic cells: a comparison

BACKGROUND: Nasal gliomas are uncommon neurogenic malformations, which derive from the prenasal space. They may appear as intranasal masses, frontonasal masses, or deformities of the nose, brow, or lower central forehead. Almost all of these tumors were diagnosed shortly after birth. The clinical findings of meningoencephaloceles, nasal fistulas, dermoides and epidermoid cysts are presented additionally for differential diagnosis. PATIENTS: Following some interesting case reports, the management of these types of benign tumors is discussed. RESULTS: Complete radiologic evaluation with computed tomography and magnetic resonance imaging should be performed, because a possible intracranial connection must be considered. The preferred surgical treatment of glioma is an endoscopically controlled procedure. In most cases craniotomy is not required. Open rhinoplasty can be helpful for removal of ectodermic malformations. CONCLUSIONS: The surgeon should be familiar with the diagnosis and management of the rare congenital tumors of the nose to ensure proper therapy and to provide the requisite information for patients, parents, and colleagues.     

Role of Langerhans cells and other dendritic cells in viral diseases

Langerhans cells are part of a vast system of potent antigen-presenting cells known under the name of dendritic cells. During the last decade, much has been learned on dendritic cell involvement in the immune response to infectious diseases. This review briefly summarizes our current understanding of the role played by Langerhans cells and other dendritic cells in the pathogenesis of DNA and RNA virus infections. These data may form the basis for the development of innovative approaches in the diagnosis, prevention, and treatment of viral diseases.     

Regulation of E-cadherin-mediated adhesion in Langerhans cell-like dendritic cells by inflammatory mediators that mobilize Langerhans cells in vivo

Adhesion of Langerhans cells (LC) to keratinocytes is mediated by E-cadherin. IL-1, TNF-alpha, and LPS mobilize LC from epidermis and presumably attenuate LC-keratinocyte adhesion. To determine whether these mediators modulated LC E-cadherin-dependent adhesion directly, we characterized their effects on LC-like dendritic cells expanded from murine fetal skin (FSDDC). FSDDC were propagated from day 16 C57BL/6 fetal skin and isolated as aggregates (FSDDC-A) in which homophilic adhesion was mediated by E-cadherin. IL-1, TNF-alpha, and LPS induced dissociation of FSDDC-A that began within 4 to 8 h and was complete within 20 h. Anti-IL-1RI mAb inhibited disaggregation caused by IL-1alpha and IL-1beta, but not that induced by TNF-alpha or LPS. Anti-TNF-alpha mAb inhibited the effect of TNF-alpha and LPS, but not that caused by IL-1alpha or IL-1beta. Flow cytometry of FSDDC-A revealed that IL-1, TNF-alpha, and LPS induced increased expression of MHC class II, CD40, and CD86 and decreased E-cadherin expression that was temporally related to dissociation of aggregates. IL-1 and TNF-alpha caused a rapid reduction in FSDDC E-cadherin mRNA levels that preceded the decrease in E-cadherin surface expression. These results demonstrate that cytokines that induce LC emigration in vivo act directly on LC-like cells in vitro, reduce E-cadherin mRNA levels, down-regulate E-cadherin surface expression, and induce a loss of E-cadherin-mediated adhesion.     

Cloning and expression of mouse liver phosphatidylserine synthase-1 cDNA. Overexpression in rat hepatoma cells inhibits the CDP-ethanolamine pathway for phosphatidylethanolamine biosynthesis

In eukaryotic cells, phosphatidylserine (PtdSer) is synthesized by two distinct synthases on the endoplasmic reticulum by a base-exchange reaction in which the polar head-group of an existing phospholipid is replaced with serine. We report the cloning and expression of a cDNA for mouse liver PtdSer synthase-1. The deduced protein sequence is >90% identical to that of PtdSer synthase-1 from Chinese hamster ovary cells and a sequence from a human myeloblast cell line. PtdSer synthase-1 cDNA was stably expressed in M.9.1.1 cells which are mutant Chinese hamster ovary cells defective in PtdSer synthase-1 activity, are ethanolamine auxotrophs, and have a reduced content of PtdSer and phosphatidylethanolamine (PtdEtn). The growth defect of M.9.1.1 cells was eliminated, and a normal phospholipid composition was restored in the absence of exogenous ethanolamine, implying that the cloned cDNA encoded PtdSer synthase. Mouse liver PtdSer synthase-1 was also expressed in McArdle 7777 rat hepatoma cells. In addition to a 3-fold higher in vitro serine-exchange activity, these cells also exhibited enhanced choline- and ethanolamine-exchange activities and incorporated more [3H]serine into PtdSer than did control cells. However, the levels of PtdSer and PtdEtn in cells overexpressing PtdSer synthase-1 activity were not increased. Excess PtdSer produced by the transfected cells was rapidly decarboxylated to PtdEtn and the degradation of PtdSer, and/or PtdEtn derived from PtdSer, was increased. Moreover, the CDP-ethanolamine pathway for PtdEtn biosynthesis was inhibited. These data suggest that (i) cellular levels of PtdSer and PtdEtn are tightly controlled, and (ii) the metabolism of PtdSer and PtdEtn is coordinately regulated to maintain phospholipid homeostasis.     

Cloning and expression of cDNA for soluble form of rat heme oxygenase-1

Heme oxygenase catalyzes the oxidation of heme to biliverdin and carbon monoxide. The gene encoding the truncated soluble rat heme oxygenase-1 (Metl-Pro267) was cloned. The enzyme protein was expressed in E. coli JM109 and purified to homogeneity. The molecular weight of the recombinant enzyme was 30 kDa as assessed by SDS-polyacrylamide gel electrophoresis. From a 3-L culture, about 90 mg of the purified enzyme was routinely obtained. The dependency of the heme oxygenase reaction catalyzed by the soluble enzyme on the NADPH-cytochrome P-450 reductase concentrations and the effect of catalase on the reaction were examined to compare with the purified membrane-bound form of heme oxygenase-1 (Yoshida and Kikuchi, 1978b). The activity of the soluble enzyme was inhibited at high concentrations of NADPH-cytochrome P-450 reductase and the inhibition was not alleviated by addition of catalase unlike the membrane-bound form. The ferric iron of the heme-heme oxygenase complex was in a typical high spin state at acidic to neutral pH (pH 6.5-7.0) but conversion to low spin state was observed at basic pH (pH 9-10). The heme bound to heme oxygenase was converted to biliverdin at a stoichiometric ratio of unity in the presence of NADPH-cytochrome P-450 reductase system. During the heme degradation of the heme-heme oxygenase complex under atmospheric oxygen, several intermediates, that is, oxygenated heme and verdoheme, were spectrally discriminated.     

Zonal expression of angiotensin II-AT1-receptor genes in rat kidneys

The trapezius osseomyocutaneous flap is the only pedicled flap that is able to transfer vascularized bone for mandibular reconstruction as well as skin for intra-extra oral reconstruction. The trapezius muscle also helps to fill the defect created by the neck dissection and covers the vessels of the neck. This flap has been used in our maxillofacial surgery service during the past 14 years. In spite of having incorporated microvascular flaps in our reconstructive techniques it continues to be one of the flaps we use in selected patients for bone and soft tissue compound defects of the oral cavity. We describe in this article our experience using this flap with dental implants in order to achieve a functional reconstruction. We also discuss when we use this flap for mandibular reconstruction and when a free vascularized flap is used.     

Erratum to "Immunocytochemical detection of cytokines and chemokines in Langerhans cells and in vitro derived dendritic cells"

We have developed a direct immunocytochemical technique to identify cytokine and chemokine production in epidermal Langerhans cells (LC) and in vitro derived CD14-, CD1a+, CD83+, CD40+ dendritic cells (DC) at the single cell level. Formaldehyde fixation combined with saponin permeabilization preserved cellular morphology and generated a characteristic juxtanuclear staining signal due to the accumulation of cytokine to the Golgi organelle. This approach was used for the assessment of TNF-alpha, IL-6, IL-8, IL-10, IL-12, GM-CSF, MIP-1alpha, MIP-1beta and RANTES producing cells. In contrast, a diffuse cytoplasmic staining was evident for IL-1ra, IL-1alpha and IL-1beta production. IL-1ra and IL-1alpha were expressed in 10-25% of unstimulated cultured cells, while all the other cytokines were undetectable. IL-1ra, IL-1alpha and IL-1beta were also the dominating cytokines, expressed in up to 85% of the DC, after 3 h of LPS stimulation. A significantly lower number of cells (0-5%) synthesized TNF-alpha, IL-6, IL-10, IL-12 and GM-CSF. The incidence of chemokine producing cells (IL-8, RANTES, MIP-1alpha, MIP-1beta) peaked 10 h after LPS stimulation in up to 60% of the DC. Both immature CD83- and mature CD83+ DC as well as LC had a similar cytokine production pattern. Thus, in comparison to monocytes, LPS stimulation of DC generated a lower incidence of TNF-alpha, IL-6, IL-10 and IL-12 producing cells while IL-1 was expressed in a comparable number of cells.     

cDNA expression studies of rat liver aryl sulphotransferase

A cDNA encoding an isoenzyme of rat liver aryl sulphotransferase was isolated from a rat liver bacteriophage Lambda gt 11 library by the polymerase chain reaction technique. The resulting cDNA was functionally expressed in COS-7 cells and characterised by determining the sulphating capacity of the cells with a range of substrates. The COS-expressed enzyme catalysed the sulphation of both phenol and dopamine with Kms of the same order as those obtained for the high affinity isozyme in rat liver cytosol, while low activity was observed with tyrosine methyl ester. The common food additive vanillin was also a good substrate for sulphate conjugation. The sulphation of vanillin catalysed by the COS-expressed enzyme was consistent with a single enzyme system, in contrast, the kinetics of the reaction catalysed by cytosolic sulphotransferase indicated that vanillin was sulphated by more than one isozyme.     

cDNA cloning and expression of rat and human protein geranylgeranyltransferase type-I

Protein geranylgeranyltransferase type-I (GGTase-I) transfers a geranylgeranyl group to the cysteine residue of candidate proteins containing a carboxyl-terminal CAAX (C, cysteine; A, aliphatic amino acid; X, any amino acid) motif in which the "X" residue is leucine. The enzyme is composed of a 48-kilodalton alpha subunit and a 43-kilodalton beta subunit. Peptides isolated from the alpha subunit of GGTase-I were shown to be identical with the alpha subunit of a related enzyme, protein farnesyltransferase. Overlapping cDNA clones containing the complete coding sequence for the beta subunit of GGTase-I were obtained from rat and human cDNA libraries. The cDNA clones from both species each predicted a protein of 377 amino acids with molecular masses of 42.4 kilodaltons (human) and 42.5 kilodaltons (rat). Amino acid sequence comparison suggests that the protein encoded by the Saccharomyces cerevisiae gene CDC43 is the yeast counterpart of the mammalian GGTase-I beta subunit. Co-expression of the GGTase-I beta subunit cDNA together with the alpha subunit of protein farnesyltransferase in Escherichia coli produced recombinant GGTase-I with electrophoretic and enzymatic properties indistinguishable from native GGTase-I.     

The actin-bundling protein fascin is involved in the formation of dendritic processes in maturing epidermal Langerhans cells

Dendritic cells (DC) are characterized by their unique potential to prime naive T cells. Epidermal Langerhans cells (LC), the DC resident in the epidermis, gain this immunostimulatory capacity following Ag contact in vivo or during in vitro culture of epidermal cell suspensions. To analyze differential gene expression in maturing LC, we constructed a highly representative cDNA library of cultivated LC (cLC) in lambda ZAP II containing 18 x 10(6) independent clones. This library was screened with freshly isolated Langerhans cell (fLC)- and cLC-derived probes for cLC-specific cDNAs. The cDNAs identified were sequenced and analyzed by database searches. Two cDNA fragments were identified as fragments of fascin, indicating that fascin is differentially expressed in LC. By competitive RT-PCR, we confirmed that fascin is highly expressed in cLC cultivated for 1, 2, and 3 days, while no signals were obtained with fLC. Western blot and immunofluorescence analysis revealed cLC-specific expression of fascin on the protein level as well. Fascin is known to be involved in the organization of the actin cytoskeleton in cytoplasmatic extensions of nerve growth cones. Its differential expression in maturing LC coincides with the formation of numerous dendritic projections in LC. Their formation was inhibited by incubation of LC with fascin antisense oligonucleotides during cultivation. Therefore, we conclude that fascin is necessary for the formation of the dendritic processes of maturing Langerhans cells and may thus influence T cell-LC interaction.     

Glucocorticoid-induced apoptosis of dendritic cells in the rat tracheal mucosa

The results of two previous studies have shown that implant porosity can be used to increase both the measured diffusion coefficients and the vascularity within the tissue encapsulating long-term subcutaneous implants. This study investigates the hypothesis that the analyte concentrations within the tissue surrounding porous implants will respond more quickly to changes in plasma levels than does the densely packed, avascular fibrous capsule surrounding nonporous implants. The average concentration of lissamine-rhodamine was measured in tissue within 100 microm of the following implants at four different times following injection of the tracer: PVA-skin, PVA-5, PVA-60, PVA-700 (polyvinyl alcohol nonporous, 5 microm, 60 microm, and 700 microm mean pore sizes, respectively) and PTFE-0.5 and PTFE-5 (polytetrafluoroethylene 0.5 microm and 5 microm mean pore sizes, respectively). The results were compared to those of unimplanted subcutaneous tissue (SQ). In addition, the data were analyzed with a simple two-compartment model in which a tissue response time constant (taup) was extracted. As in the case of vascular density, the cellular dimension of the PVA-60 pore sizes produced surrounding tissue with the optimum response times to changes in plasma concentrations. The concentrations of rhodamine within the tissue surrounding the PVA-60 implant were the highest at all time points and responded to the change in plasma rhodamine concentration approximately three times more quickly (taup = 764 s) than the fibrous tissue encapsulating the nonporous PVA-skin (taup = 2058 s) and more than twice as quickly as SQ (taup = 1627 s). The overall mass transfer rate between plasma and the tissue surrounding the different implants calculated from the permeability and density of vessels from the previous study correlated very well (r2 = 0.7, p < .02, slope of 0.98) with the reciprocal of the tissue response time constant (taup).     

Molecular characterization of a human tyrosinase-related-protein-2 cDNA. Patterns of expression in melanocytic cells

Pigmentation in mammals is under complex genetic control. Amongst the genes involved in this process, those encoding tyrosinase and the tyrosinase-related-proteins 1 and 2 have been well characterized and share a number of features. Recently, the murine tyrosinase-related-protein-2 gene was shown to encode dopachrome-tautomerase activity and was mapped to the slaty locus. Human tyrosinase and tyrosinase-related-protein-1 genes have been isolated and demonstrate a high degree of similarity with their murine counterparts. However, there has been limited data regarding the existence of a human homologue for tyrosinase-related-protein-2 and its relationship to the other tyrosinase-related proteins. In this study, we report the molecular isolation of a cDNA encoding a human homologue of the murine tyrosinase-related-protein-2/dopachrome tautomerase. We have characterized its expression in human melanocytic cells and have analyzed the relationship between dopachrome tautomerase and tyrosinase activities with the level of visible pigmentation in these cells. TYRP2 has been mapped to the chromosomal region 13q32, thus extending a region of synteny with mouse-chromosome 14.     

CD1 expression by dendritic cells in human leprosy lesions: correlation with effective host immunity

A potential role for the CD1 family of lipid Ag-presenting molecules in antimicrobial immunity in vivo was investigated in human leprosy skin lesions. Strong induction of three CD1 proteins (CD1a, -b, and -c) was observed in dermal granulomas in biopsy samples of involved skin from patients with the tuberculoid form of leprosy or with reversal reactions, which represent clinical patterns of disease associated with active cellular immunity to Mycobacterium leprae. In contrast, lesions from patients with the lepromatous form of the disease who lack effective cell-mediated immunity to the pathogen did not show induction of CD1 proteins. Thus, expression of CD1 correlated directly with effective immunity to M. leprae, as assessed by the clinical course of infection. CD1a, -b, and -c could be induced to similar levels on monocytes from the blood of either tuberculoid or lepromatous leprosy patients. This suggested that the absence of expression in lepromatous lesions was most likely due to local factors at the site of infection as opposed to a primary defect of the CD1 system itself. The majority of cells expressing CD1 in leprosy lesions were identified as a population of CD83+ dendritic cells. Initial in vitro studies of the Ag-presenting function of CD1+CD83+ monocyte-derived dendritic cells showed that such cells were highly efficient APCs for CD1-restricted T cells. These results indicate that the CD1 system can be up-regulated in human infectious diseases in vivo, and may play a role in augmenting host defense against microbial pathogens.     

Cloning, sequencing, and heterologous expression of rat methionine synthase cDNA

Methionine synthase catalyzes cobalamin-dependent methyl transfer reaction from 5-methyltetrahydrofolate to homocysteine, forming methionine. Rat methonine synthase cDNA was cloned and analyzed by RT-PCR, 3'- and 5'-RACE techniques. The cDNA consists of a 0.3-kb upstream untranslated region, a 3.8-kb coding region, and a 0.4-kb downstream untranslated region. The open reading frame encoded a polypeptide of 1,253 amino acid residues with a calculated molecular weight of 139,162. This molecular weight was in good agreement with the observed one (143,000) of the purified rat liver enzyme. The deduced amino acid sequence was 53, 92, and 64% identical with those of the Escherichia coli, human, and presumptive Caenorhabditis elegans enzymes, respectively. All the fingerprint sequences, forming parts of the cobalamin- and S-adenosylmethionine-binding sites, were completely conserved in the rat methionine synthase. A high-level expression of catalytically active enzyme in insect cells was done by infection with a baculovirus containing the rat methionine synthase cDNA.