Human monocytoid THP-1 cell line versus monocyte-derived human immature dendritic cells as in vitro models for predicting the sensitising potential of chemicals.

Immature dendritic cells (DCs) modulate differentiation markers following in vitro exposure to chemicals generating contact allergies. THP-1 is a monocytoid cell line maintaining some differentiating plasticity. In this study, human DCs and THP-1 cells were compared as in vitro models to predict contact sensitisation of chemicals with different sensitising potential. Expression of CD80 and CD86 was assessed by flow cytometry after exposure to subtoxic concentrations of potent (2,4-dinitrochlorobenzene, DNCB and p-phenylendiamine, PPD), strong (thimerosal, TMS), moderate (sodium tetrachloroplatinate, Na2PtCl4) sensitising compounds as well as of non-sensitising, irritating sodium dodecyl sulphate (SDS) as compared to a vehicle of sensitising substances (dimethyl sulphoxide, DMSO). Up-regulation of CD86 following in vitro incubation of DCs and THP-1 cells with DNCB, PPD, TMS and Na2PtCl4, but not with SDS, was observed. The CD80 membrane marker was up-regulated on DCs following in vitro incubation with DNCB and PPD, but not with TMS, Na2PtCl4. and SDS. On THP-1 cells, only DNCB up-regulated CD80 expression. In conclusion, both the cell line THP-1 and DCs are promising in vitro models for assays aiming at predicting the sensitisation potential of chemicals. THP-1 cell line is by far easier to handle and offers relevant advantages from the practical point of view.

[Experimental survey of a new topical anti-oxidant based on furfuryl palmitate in the treatment of child's and baby's dermatitis with eczema: results from a multicenter clinical investigation]. / Sperimentazione di un nuovo antiossidante topico a base di Furfuril palmitato nel trattamento delle dermatiti eczematose del bambino e del neonato. Risultati di uno studio clinico multicentrico.

In this paper we present the preliminary results of a multi-center clinical investigation carried out on a new topical product (Triderm(R) Lenil+) containing Superoxidodismutase (SOD), 18-beta glycyrrethic acid, Vitamin E, alpha bisabolol and a new patented antioxidant molecule, Furfuryl palmitate. These active agents altogether protect skin from cell damages that promote the inflammatory syndrome; their action is furthermore sustained by agents such as phytosphingosine and phytosterols that act to repair the skin barrier. Furfuryl palmitate is an ester with a strong quenching ability towards the singlet oxygene (1O2) and with a high permeability potential through the biological membranes, thanks to its lipophylic formula. Further than being among the main responsible for skin ageing, the 1O2 is involved in the genesis of many topical pathologies such as allergic and irritant dermatitis, atopic dermatitis, inflammation, psoriasis and sunburns. The product has been extensively tested for its effectiveness and skin tolerability on a selected population of 60 children and babies with age ranging from 2 months to 14 years, suffering mainly with atopic dermatitis and irritant dermatitis. The topical use of the product caused a significant improvement of the inflammatory skin conditions, with evident and fast inflammation and eczema reduction in all the investigated pathologies, as shown in the present study. The product has been formulated in order to avoid any sensitisation risk and did not show any relevant side effect. It is particularly suitable in the treatment of pediatric dermatitis with symptoms like eczema, itching, desquamation and xerosis.

Actions of molecules which regulate hemopoiesis on endothelial cells: memoirs of common ancestors?

The proliferation and differentiation of hematopoietic stem cells (hematopoiesis) takes place in close contact with stromal cells and matrix in bone marrow. Hematopoiesis requires cytokines, collectively termed colony stimulating factors (CSFs), which act on progenitor cell populations and induce their commitment to a specific lineage. For instance, leukemia, inhibitor factor and stem cell factor act on pluripotent cells and immature progenitors, granulocyte-macrophage colony stimulating factor (GM-CSF) acts at early stages of the development of myelomonocytic lineage, whereas granulocyte-colony stimulating factor (G-CSF) and macrophage-colony stimulating factor (M-CSF) act on more mature cells of the same lineage and are only required later during the differentiation of this cell lineage. A second important element for the hematopoietic process is the presence of extracellular matrix proteins, which bind CSFs and correctly present the molecules to specific receptors present on the surface of the progenitor cells. Finally, stromal cells (i.e. fibroblasts, endothelial cells and adipocytes) which support the growth of hematopoietic stem cells in vitro, are crucial for the production of CSFs and protein matrix and regulate the passage of mature cells from bone marrow to bloodstream. Idiopathic myelofibrosis is an example of the relevance of microenvironment in hematopoiesis. This disease is characterized by fibroblast and basement membrane accumulation, appearance of myofibroblasts and modification of the capillary network and provokes a bone marrow aplasia. In this article we review recent studies on the role of hemopoietic cytokines on stromal cells, in particular on endothelial cells, and propose a double role for CSFs in hematopoiesis: to induce the commitment of progenitor cells and to maintain the behavior of bone marrow endothelial cells.

Differential expression of the common beta and specific alpha chains of the receptors for GM-CSF, IL-3, and IL-5 in endothelial cells.

The present study was designed to reexamine the interaction of granulocyte-macrophage colony-stimulating factor (GM-CSF) with endothelial cells (EC) and to investigate the expression of CSF receptor chains in these cells. In agreement with previous data, GM-CSF induced directional migration and, to a lesser degree, proliferation of human umbilical vein EC. When compared to basic fibroblast growth factor, GM-CSF was comparable in terms of chemotactic activity and was substantially less active in terms of proliferation. Binding studies confirmed the presence of receptors for GM-CSF (GM-CSFR) on EC. The expression of the beta chain common to the GM-CSFR, IL-3 receptor, and IL-5 receptor, as well as of the individual alpha chains, was studied by Northern analysis and/or reverse transcription and polymerase chain reaction. EC expressed high levels of the common beta chain transcripts. Expression of the alpha(GM) and alpha(IL-5) chain mRNA was minimal or absent in normal EC, though the transformed ECV304 endothelial cell line had substantial amounts of alpha(GM) chain mRNA. Unexpectedly, EC expressed alpha(IL-3) chain transcripts. IL-3 induced migration of EC across polycarbonate filters, whereas IL-5 was inactive.

Proliferative and migratory responses of murine microvascular endothelial cells to granulocyte-colony-stimulating factor.

Microvascular murine endothelial cells lines transformed by middle T oncogene of polyoma virus maintain the biological characteristics of nontransformed microvascular endothelial cells (EC). By using cell lines originated from different anatomical districts (thymus, brain, heart, and skin), we demonstrated that murine granulocyte-colony-stimulating factor (G-CSF) induces proliferation of murine microvascular endothelial cells at nanomolar concentrations without any cooperation with fetal calf serum. The proliferative effect on murine cells is less than that elicited by epidermal growth factor (EGF), used as standard for this function. G-CSF also promotes the migration of tEnd.1 endothelial cell line assayed by Boyden chamber technique. The analysis of transcript for G-CSF receptor (G-CSFR) by Northern blot hybridization and by reverse-transcriptase polymerase chain reaction (RT-PCR) shows that these cell lines have specific mRNA, with the size of that present in myeloid cells. These results indicate that G-CSF operates in the microvascular endothelial cells by a mechanism related to the presence of a specific receptor.

Cytokine mRNA expression by cultured rat mesangial cells after contact with environmental lectins.

We previously demonstrated that gliadin, a lectinic component of gluten, induces IgA mesangial deposits in orally immunized mice, binds in vitro polymeric IgA and cultured rat mesangial cells modulating their arachidonic acid metabolism. We investigated the effects of gliadin and other environmental lectins on some mesangial cell functions, including synthesis and release of cytokines and lipid mediators. Several lectins, particularly gliadin, affected the mRNA expression of c-myc and c-fos, two proto-oncogenes involved in the transcriptional enhancement of the gene cascade, which are markers of cell growth, differentiation and mitosis. Lectins modulated the ability of cultured rat mesangial cells to express mRNA for cytokines involved in the inflammation and in the regulation of the immune response. TNF-alpha and IL-6 mRNA transcription were enhanced by gliadin and other lectins, and TNF release was variably increased. Conversely, IL-1 production was less affected or slightly depressed. PAF production was not detectable while PGE2 was generally reduced and TXB2 enhanced. Gliadin was one of the lectins most active on the mesangial cells, and its effects were reversed by the addition of N-Acetylglucosamine, a sugar specific for some lectinic bindings, suggesting a carbohydrate interaction. The effects of the various lectins were distinct and only partially convergent, ruling out an aspecific mesangial cell activation. These data suggest that lectins might interfere with mesangial cell functions and modify the mesangial cell homeostasis.

Recent developments in the cell biology of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor: activities on endothelial cells.

Granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor were considered as growth and differentiation factors restricted to hematopoietic cells. It was recently found that non-hematopoietic cells, including endothelial cells, respond to these cytokines. In this review we describe their effects on endothelial cells, underlining their role in the behavior and survival of the microenvironment of bone marrow, in the angiogenesis process related to the progression of solid tumors and of vascular tumors, and in the homing of lymphocytes.

Hepatocyte growth factor is a potent angiogenic factor which stimulates endothelial cell motility and growth.

Hepatocyte Growth Factor (HGF, also known as Scatter Factor) is a powerful mitogen or motility factor in different cells, acting through the tyrosine kinase receptor encoded by the MET protooncogene. Endothelial cells express the MET gene and expose at the cell surface the mature protein (p190MET) made of a 50 kD (alpha) subunit disulfide linked to a 145-kD (beta) subunit. HGF binding to endothelial cells identifies two sites with different affinities. The higher affinity binding site (Kd = 0.35 nM) corresponds to the p190MET receptor. Sub-nanomolar concentrations of HGF, but not of a recombinant inactive precursor, stimulate the receptor kinase activity, cell proliferation and motility. HGF induces repairs of a wound in endothelial cell monolayer. HGF stimulates the scatter of endothelial cells grown on three-dimensional collagen gels, inducing an elongated phenotype. In the rabbit cornea, highly purified HGF promotes neovascularization at sub-nanomolar concentrations. HGF lacks activities related to hemostasis-thrombosis, inflammation and endothelial cells accessory functions. These data show that HGF is an in vivo potent angiogenic factor and in vitro induces endothelial cells to proliferate and migrate.

Synthesis of platelet-activating factor by polymorphonuclear neutrophils stimulated with interleukin-8.

Human interleukin-8 (IL-8) was evaluated for its capability to induce the synthesis and release of platelet-activating factor (PAF) from human polymorphonuclear neutrophils (PMN). IL-8 promotes in a dose-dependent fashion (1-100 ng/ml) a rapid synthesis of PAF, which is only partially released. The synthesis of PAF is preceded by the activation of acetyl-CoA: 1-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyl-transferase, suggesting that IL-8 activates the "remodeling pathway" of PAF synthesis. By thin layer chromatography and reverse-phase high pressure liquid chromatography, we demonstrated that PAF synthesized by human PMN stimulated with IL-8 is heterogeneous: the 2-acetylated phospholipids having the biological and physicochemical characteristics of PAF include the 1-O-alkyl form, which is produced in large extent (51%), and the 1-acyl form (20%). The analysis of the individual molecular species of radyl chain indicated nine peaks, 16:0 and 18:0 being the predominant forms. These results identify PAF as a direct product of IL-8 stimulation in PMN.

Murine endothelioma cell lines transformed by polyoma middle T oncogene as target for and producers of cytokines.

We studied cytokine-related functional properties of four mouse endotheliomas from different anatomical sites obtained by transformation with middle T oncogene. We examined mRNA expression of IL-6, IL-1 alpha, macrophage-CSF, granulocyte/macrophage-CSF, and two members of an emerging super-family of chemotactic cytokines (JE/monocyte chemoattractant protein-1 (MCP-1) and KC). Exposure to IL-1 augmented or induced cytokine gene transcripts in three endothelioma lines (eEnd.1, sEnd.1, and tEnd) with maximal expression in tEnd.1 cells. Endothelioma cells also responded to TNF-alpha and LPS. Levels of IL-6 and monocyte chemotactic activity (a JE/MCP activity) correlated with mRNA expression. IL-1 also induced production of procoagulant activity and platelet-activating factor in endothelioma cells, with heterogeneity in the levels of response among individuals lines. Murine melanoma B16-F1, human colon carcinoma HT29 cells, CB33MT lymphoblastoid cells, and monocytes adhered to endothelioma monolayers and the adhesive properties of these cell lines were modulated by IL-1 beta, with marked differences among themselves. Murine EC derived from brain capillaries, used as control, shared several properties with bEnd.4 line. Endothelioma lines cause tumors by recruiting host cells. The capacity to produce cytokines that directly or indirectly attract host vascular cells, may play an important role in hemangioma induction in vivo. Murine endothelioma lines, generated by transformation with the polyoma middle T oncogene, retain functional properties of normal endothelium, and may represent an invaluable tool for analysis of the immunobiology and heterogeneity of EC in different tissues.