Different cytokines regulate antigen uptake and presentation of a precursor dendritic cell line.

Langerhans cells (LC) and dendritic cells (DC) need to be activated in order to perform their antigen-presenting function. In this study, we explored the influence of cytokines on the uptake and presentation of protein antigens by the retrovirally immortalized myeloid cell line FSDC. This cell line was generated from mouse fetal skin and was previously shown to have the characteristics of early DC precursors.

Native nicotinic acetylcholine receptors in human Imr32 neuroblastoma cells: functional, immunological and pharmacological properties.

IMR32 cells express two classes of surface nicotinic receptors: those labelled with high affinity by [125I]neuronal toxin, and those labelled by [125I]alpha-bungarotoxin. Whole-cell patch-clamp recordings indicate that both classes of receptor are able to elicit inward currents that are totally blocked by d-tubocurarine but only partially blocked by alpha-bungarotoxin. In IMR32 cells, nicotine induces an increase in the intracellular level of free Ca2+.

Immunolocalization of secretogranin II and insulin in a nerve growth factor-differentiated insulinoma cell line.

RINm5F, a rat insulin-secreting pancreatic cell line, responds to nerve growth factor (NGF) by extending neurite-like processes. Secretogranin II (SgII), a marker of neuroendocrine secretory organelles, has recently been found to be a good marker of neuronal differentiation in both human neuroblastoma and rat pheochromocytoma cells. The present paper reports the results obtained from immunocytochemical studies, which show that NGF increases the expression of SgII-immunolabeled organelles in RINm5F cells.

Calcitonin gene-related peptide: possible role in formation and maintenance of neuromuscular junctions.

The expression and content of calcitonin gene-related peptide (CGRP) and secretogranin II (SgII) in adult rat motor neurons were examined by in situ hybridization, Northern blot analysis, and immunocytochemistry. Normal motor nerve terminals did not contain detectable CGRP or SgII. Ten to 15 days after a peripheral nerve crush about 80% of the motor nerve terminals reinnervating the soleus (SOL) muscle contained detectable CGRP but no SgII.

myc-immortalized microglial cells express a functional platelet-activating factor receptor.

The autacoid platelet-activating factor (PAF) takes part in a complex network of interactions regarding the cellular components of nervous tissues. Efforts aimed at characterizing the effects of PAF in the brain have been recently focalized on neurons because PAF exerts pleiotropic effects on these cells. Less attention has instead been paid to the glial component of the brain.

Mechanisms of synaptogenesis in hippocampal neurons in primary culture.

To improve our understanding of the mechanisms which regulate the formation and the functional maturation of synaptic contacts between neurons, we used hippocampal neurons maintained in primary cultures as experimental system. In this model, which offers several advantages for the study of neuronal development and synaptogenesis, we investigated some of the cellular mechanisms underlying the formation of presynaptic and postsynaptic compartments.

Modulation of cytokine expression in mouse dendritic cell clones.

Dendritic cells (DC) play an essential role in the induction of primary immune responses; however, very little information is available on cytokine production by DC. Here we determined the cytokine gene expression profile of two immortalized DC clones, CB1 and D2SC/1, both generated from mouse spleen but differing in their activation requirements. Among the cytokines tested, only transforming growth factor-beta 1 was transcribed constitutively, but its production was detected only in D2SC/1 cells after treatment with granulocyte/macrophage colony-stimulating factor (GM-CSF).

Retroviral immortalization of phagocytic and dendritic cell clones as a tool to investigate functional heterogeneity.

We have developed a method to generate immortalized phagocytic and dendritic cell clones from various mouse tissues such as spleen, thymus, brain and bone marrow. The clones were phenotypically characterized and shown to retain the ability to respond to immune or inflammatory signals, e.g.

Molecular cloning of a recombinant retrovirus carrying a mutated envAKR-mycMH2 fusion gene immortalizing cells of the monocytic-macrophage lineage.

The VN-11 recombinant retroviruses, originally generated by co-transfection of the avian MH2 and AKRv viral genomes, were molecularly cloned from an infected mouse cell line named N11. The analysis of the proviral genome sequence from one of these recombinants showed a possible envAKR-mycMH2 fusion. Point mutations were also found in this envAKR-mycMH2 gene.

Serotonin release and cell proliferation are under the control of alpha-bungarotoxin-sensitive nicotinic receptors in small-cell lung carcinoma cell lines.

Neuronal type nicotinic acetylcholine receptors (nAchRs) have recently been identified in small-cell lung carcinoma. We here show that both nicotine and cytisine stimulate [3H]serotonin release in a dose-dependent manner; this effect is antagonized by alpha-bungarotoxin (alpha Bgtx) and alpha-conotoxin MI (alpha Ctx). Nicotine and cytisine stimulate in vitro SCLC proliferation and this effect is completely antagonized by both alpha Bgtx and alpha Ctx.

Developmentally regulated expression of CGRP in the mouse olfactory pathway.

The pattern of expression of the neuropeptide CGRP and its encoding mRNA has been determined by immunohistochemistry and in situ hybridization in the mouse olfactory pathway during development. Specific CGRP transcripts are first detected at E13 followed by the appearance of the peptide at E15. Both peptide and transcript are present until birth; their expression then appears to be down-regulated since postnatally the peptide is only observed in some olfactory receptor neurons.

Brefeldin A inhibits the formation of constitutive secretory vesicles and immature secretory granules from the trans-Golgi network.

The effects of brefeldin A (BFA) on membrane traffic between the trans-Golgi network (TGN) and the plasma membrane were investigated in intact PC12 cells and in a cell-free system derived from PC12 cells. In intact cells, BFA caused a virtually complete block of constitutive secretion, as indicated by the lack of release from, and accumulation in, the cells of a [35S]sulfate-labeled heparan sulfate proteoglycan (hsPG). Pulse-chase experiments with [35S]sulfate followed by subcellular fractionation showed that this block was due to the inhibition of formation of constitutive secretory vesicles (CSVs) from the TGN.

Amine uptake inhibition by diosmin and diosmetin in human neuronal and neuroendocrine cell lines.

Human neuroblastoma cells of sympathetic origin have been used for studying the effects of diosmin and its metabolite diosmetin (vasotonic agent) on amine reuptake systems. Neuroblastoma cells take up 3H-dopamine in a specific and time-dependent manner. 3H-dopamine uptake was dose-dependently inhibited by the known antagonist desipramine.

ATP-induced Ca2+ influx is regulated via a pertussis toxin-sensitive mechanism in a PC12 cell clone.

A PC12 cell clone that responds to ATP with polyphosphoinositide hydrolysis and with a marked, biphasic intracellular free Ca2+ concentration ([Ca2+]i) response (composed by release from intracellular stores accompanied by stimulated influx from the medium), was pretreated with pertussis toxin. In the pretreated cells the responses induced by ATP were differently modified. Polyphosphoinositide hydrolysis and Ca2+ release were moderately inhibited whereas Ca2+ influx was enhanced.

A functional alpha-bungarotoxin receptor is present in chick cerebellum: purification and characterization.

It has recently been demonstrated that alpha-bungarotoxin receptors, which behave as functional nicotinic receptors, are present in chick CNS. In this paper, we report the purification and characterization of a functional alpha-bungarotoxin receptor from chick cerebellum, a nervous tissue in which a clear inhibition of induced nicotine effects has been reported in vivo. This receptor contains at least three subunits of apparent mol.

Subcellular distribution of two spin trapping agents in rat heart: possible explanation for their different protective effects against doxorubicin-induced cardiotoxicity.

Previous investigations, performed on isolated rat atria, showed that the lipophylic spin-trapping agent N-tert-butyl- alpha-phenylnitrone (PBN) is able to prevent the acute cardiotoxic effects produced by doxorubicin (DXR), whereas the hydrophylic compound 5,5-dimethyl-pyrroline-N-oxide (DMPO) is inactive. The present study was designed to ascertain whether differences in the pharmacological effects of the two spin traps are related to their different subcellular distribution. Langendorff rat hearts were perfused for 60 minutes with [14C]-DXR and either PBN or DMPO.

Pharmacokinetics and metabolism of oral diosmin in healthy volunteers.

Pharmacokinetic studies of diosmin were performed after an oral administration to healthy volunteers. Diosmin and its aglycone, diosmetin, were determined by HPLC and LC-MS techniques. At least, at the level of sensitivity of our method, no parent compound was present in the plasma but only its aglycone, diosmetin.

Physiopathology of neuronal voltage-operated calcium channels.

Voltage-operated calcium channels are multimeric transmembrane proteins crucially involved in control of calcium homeostasis. Multiple types of voltage-operated calcium channels have been described in both the nervous system and peripheral tissues. Different channels can be classified according to either their biophysical properties or their pharmacology, biochemical and molecular structure, and localization and functional role.

[Ca2+]i oscillations from internal stores sustain exocytic secretion from the chromaffin cells of the rat.

A large (65%) fraction of in vitro cultured rat chromaffin cells exhibit spontaneous [Ca2+]i oscillations, and the rest can be recruited to oscillate by appropriate stimulations. Based on fura-2 single cell [Ca2+]i measurements, evidence is provided that these oscillations originate, via the activation of Ca(2+)-induced Ca(2+)-release, from intracellular Ca2+ stores in rapid equilibrium with extracellular Ca2+. By combining [Ca2+]i measurements with a specific plaque secretion assay we demonstrate that oscillating cells exhibit a spontaneous exocytic secretory activity whereas the cells with stable [Ca2+]i do not.

Multiple actions of SC 38249: the blocker of both voltage-operated and second messenger-operated Ca2+ channels also inhibits Ca2+ extrusion.

((+-)-1,-2,3-bis-[(4-Methoxyphenyl)-methoxy]propyl)-1H-imidazole (SC 38249) and its 4-methoxyphenetyl analogue (SKF 96365) have been recently reported to block not only voltage-operated Ca2+ channels, but also the channels (second messenger-operated) that open after receptor activation of polyphosphoinositide hydrolysis in smooth muscle fibers and platelets. Fura-2 fluorescence studies in cerebellar neurons, glial and PC12 cells confirmed these effects of SC38249 and in addition demonstrated that the drug causes an inhibition of Ca2+ extrusion, presumably via the Ca2+ ATPase. This effect was particularly evident when [Ca2+]i was increased, regardless of treatment (glutamate or ionomycin).

Correlation between quantal secretion and vesicle loss at the frog neuromuscular junction.

1. We measured the rate of occurrence of miniature endplate potentials (MEPPs) at identified endplates in frog cutaneous pectoris muscles treated with crude black widow spider venom (BWSV) or purified alpha-latrotoxin (alpha-LTX) in calcium-free solutions, and we examined the relationship between the length of the nerve terminal and the total number of quanta secreted, and the relationship between the number of quanta secreted and the number of vesicles remaining at different times. 2.