Mediator release from mast cells (MC) is a crucial step in allergic and non-allergic inflammatory disorders. However, the final events in response to activation leading to membrane fusion and thereby facilitating degranulation have hitherto not been analyzed in human MC. Soluble N-ethyl-maleimide-sensitive factor attachment protein receptors (SNARE) represent a highly conserved family of proteins that have been shown to mediate intracellular membrane fusion events. Here, we show that mature MC isolated from human intestinal tissue express soluble N-ethylmaleide sensitive factor attachment protein (SNAP)-23, Syntaxin (STX)-1B, STX-2, STX-3, STX-4, and STX-6 but not SNAP-25. Furthermore, we found that primary human MC express substantial amounts of vesicle associated membrane protein (VAMP)-3, VAMP-7 and VAMP-8 and, in contrast to previous reports about rodent MC, only low levels of VAMP-2. Furthermore, VAMP-7 and VAMP-8 were found to translocate to the plasma membrane and interact with SNAP-23 and STX-4 upon activation. Inhibition of SNAP-23, STX-4, VAMP-7 or VAMP-8, but not VAMP-2 or VAMP-3, resulted in a markedly reduced highaffinity IgE receptor-mediated histamine release. In summary, our data show that mature human MC express a specific pattern of SNARE and that VAMP-7 and VAMP-8, but not VAMP-2, are required for rapid degranulation.Supporting Information for this article is available at http://www.wiley-vch.de/contents/jc_2040/2008/37634_s.pdf IntroductionMast cells (MC) are well known to play a key role in allergic and a number of non-allergic inflammatory conditions. They are capable of releasing a number of pre-stored or de novo synthesized proinflammatory ** The first two authors contributed equally to this work. The role of SNARE-proteins in human MC is still largely elusive. However, experiments conducted in rodent basophilic leukemia cells (RBL-2H3), a widely used MC cell line, have provided solid data, that members of the SNARE-family are indeed specifically expressed in different compartments of these cells and that they are crucially involved in mediator secretion [16][17][18][19][20]. These reports attribute a key role in exocytotic events in MC to the t-SNARE SNAP-23 [21]. SNAP-23 represents the ubiquitously expressed counterpart of its neuronal isoform and is found in tissues throughout the body [21,23,24]. Furthermore, SNAP-23 has been demonstrated to mediate exocytosis in other immune cells as well [12,25,26]. It forms a stable SNARE complex together with a syntaxin (STX), another t-SNARE. Various STX-isoforms have been identified in myeloid cells [12,27,28]. Finally, docking and fusion events at the plasma membrane require v-SNARE, namely vesicle-associated membrane proteins (VAMP). Different VAMP isoforms seem to be specifically involved in mediating the various intracellular trafficking events. VAMP-1 and VAMP-2, also called synaptobrevins, have been implicated in regulated exocytosis in neurons [29] and non-neuronal cells [30], while VAMP-3, or cellubrevin, was attributed a role in consti...
Cryptococcal meningoencephalitis represents a serious infection of the central nervous system, where reliable prognostic factors during the disease course are needed. Twenty-one patients diagnosed with cryptococcal meningoencephalitis in a German university hospital from 1999 to 2013 were analysed retrospectively. CSF parameters were analysed prior to therapy and during antifungal treatment and were compared between patients who survived or deceased. Fifteen patients clinically improved after antifungal therapy, while six patients died. No differences were observed between the outcome groups for the CSF parameters cell count, lactate, total protein, and CSF-serum albumin quotients (QAlb). Follow-up examinations of serum cryptococcal antigen titer and CSF cell count have shown that these parameters cannot be used to monitor the efficacy of antifungal therapy as well. In contrast, the course of QAlb during therapy was indicative for the outcome as a possible prognostic marker. In patients with clinical improvement QAlb values were falling under therapy, while rising QAlb values were found in patients with fatal outcome indicating a continuing dysfunction of the blood-CSF barrier. In conclusion, our results indicate that, among the various CSF parameters, the course of QAlb presents a promising marker that might be used to monitor the efficacy of antifungal therapy.
Abstract-The hypothalamus supports basic motivational behaviours such as mating and feeding. Recording directly from the posterior inferior hypothalamus in a male patient receiving a deep brain stimulation (DBS) electrode for the alleviation of cluster headache, we tested the hypothalamic response to different classes of motivational stimuli (sexually relevant: pictures of dressed and undressed women; pictures of food) and pictures of common objects as control. Averaged local field potentials (LFP) to sexually relevant stimuli were characterized by a biphasic significantly enhanced response (relative to objects; bootstrapping statistics) with a first phase starting at around 200 ms and a second phase peaking at around 600 ms. Sexually relevant stimuli also showed a greatly enhanced positivity relative to other stimulus classes in surface event-related potentials in a group of 11 male control participants. It is suggested that the hypothalamus is involved in the recruitment of attentional resources by sexually relevant stimuli reflected in this surface positivity. In a second session, the response to food stimuli relative to objects was tested in two states: after fasting for 14 h, LFPs to food and object stimuli showed significant differences in between 300 and 850 ms, which disappeared after a full high-calorie meal, thus replicating classic studies in monkeys [Rolls et al., Brain Res (1976) 111:53-66]. The current data are the first to demonstrate hypothalamic responses to the sight of motivational stimuli in man and thus shows that recording from DBS electrodes might provide important information about the cognitive functions of subcortical structures.
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