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Background: In many neuroinflammatory diseases, dendritic cells (DCs) accumulate in several compartments of the central nervous system (CNS), including the cerebrospinal fluid (CSF). Myeloid DCs invading the inflamed CNS are thus thought to play a major role in the initiation and perpetuation of CNS-targeted autoimmune responses. We previously reported that, in normal rats, DCs injected intra-CSF migrated outside the CNS and reached the B-cell zone of cervical lymph nodes. However, there is yet no information on the migratory behavior of CSF-circulating DCs under neuroinflammatory conditions. Methodology/Principal Findings: To address this issue, we performed in vivo transfer experiments in rats suffering from experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. EAE or control rats were injected intra-CSF with bone marrow-derived myeloid DCs labeled with the fluorescent marker carboxyfluorescein diacetate succinimidyl ester (CFSE). In parallel experiments, fluorescent microspheres were injected intra-CSF to EAE rats in order to track endogenous antigen-presenting cells (APCs). Animals were then sacrificed on day 1 or 8 post-injection and their brain and peripheral lymph nodes were assessed for the presence of microspheres+ APCs or CFSE+ DCs by immunohistology and/or FACS analysis. Data showed that in EAE rats, DCs injected intra-CSF substantially infiltrated several compartments of the inflamed CNS, including the periventricular demyelinating lesions. We also found that in EAE rats, as compared to controls, a larger number of intra-CSF injected DCs reached the cervical lymph nodes. This migratory behavior was accompanied by an accentuation of EAE clinical signs and an increased systemic antibody response against myelin oligodendrocyte glycoprotein, a major immunogenic myelin antigen. Conclusions/Significance: Altogether, these results indicate that CSF-circulating DCs are able to both survey the inflamed brain and to reach the cervical lymph nodes. In EAE and maybe multiple sclerosis, CSF-circulating DCs may thus support the immune responses that develop within and outside the inflamed CNS. [ABSTRACT FROM AUTHOR]

In vitro studies have pointed to the collapsin response mediator proteins (CRMPs) as key regulators of neurite outgrowth and axonal differentiation. CRMP3 is expressed mostly in the nervous system during development but remains at high levels in the hippocampus of adults. To explore CRMP3 function in vivo, we generated mice with targeted disruption of the CRMP3 gene. Immunohistochemistry and Golgi staining of CA1 showed abnormal dendrite and spine morphogenesis in the hippocampus of CRMP3-deficient mice. Apical dendrites displayed an increase in undulation and a reduction in length and branching points. Basal dendrites also exhibited a reduction in length with an alteration in soma stem distribution and an increased number of thick dendrites localized in stratum oriens (SO). Long-term potentiation (LTP) was impaired in this area. These data indicate an important role for CRMP3 in dendrite arborization, guide-posts navigation, and neuronal plasticity. [ABSTRACT FROM AUTHOR]

Collapsin response mediator proteins (CRMPs) consist of five homologous cytosolic proteins that participate in signal transduction involved in a variety of physiological events. CRMP1 is highly expressed during brain development; however, its functions remains unclear. To gain insight into its function, we generated CRMP1−/– mice with a knock-in LacZ gene. No gross anatomical changes or behavioral alterations were observed. Expression of CRMP1 was examined by the expression of the knocked-in LacZ gene, in situ hybridization with riboprobes and by imunohistochemistry. CRMP1 was found to be highly expressed in the developing the cerebellum, olfactory bulbs, hypothalamus and retina. In adults, expression level was high in the olfactory bulbs and hippocampus but very low in the retina and cerebellum and undetectable in hypothalamus. To study potential roles of CRMP1, we focused on cerebellum development. CRMP1−/– mice showed a decrease in the number of granule cells migrating out of explants of developing cerebellum, as did treatment of the explants from normal mice with anti-CRMP1 specific antibodies. CRMP1−/– mice showed a decrease in granule cell proliferation and apoptosis in external granule cell layers in vivo. Adult cerebellum of CRMP1−/– did not show any abnormalities. [ABSTRACT FROM AUTHOR]

The choroid plexuses (CPs) form a protective interface between the blood and the ventricular cerebrospinal fluid (CSF). To probe into the pathways by which CPs provide brain protection, we sought to evaluate the efficiency of glutathione conjugation in this barrier as a mechanism to prevent the entry of blood-borne electrophilic, potentially toxic compounds into the CSF, and we investigated the fate of the resulting metabolites. Rat CPs, as well as human CPs from both fetal and adult brains, displayed high glutathione-S-transferase activities. Using an in vitro model of the blood–CSF barrier consisting of choroidal epithelial cells cultured in a two-chambered device, we showed that glutathione conjugation can efficiently prevent the entry of 1-chloro-2,4-dinitrobenzene (CDNB) into the CSF, a model for electrophilic compounds. The duration of this enzymatic protection was set by the concentration of CDNB to which the epithelium was exposed, and this barrier effect was impaired only on severe epithelial intracellular glutathione and cysteine depletion. The conjugate was excreted from the choroidal cells in a polarized manner, mostly at the blood-facing membrane, via a high-capacity transport process, which is not a rate-limiting step in this detoxification pathway, and which may involve transporters of the ATP-binding cassette c(Abcc) and/or solute carrier 21 (Slc21) families. Supplying the choroidal epithelium at the blood-facing membrane with a therapeutically relevant concentration of N-acetylcysteine sustained this neuroprotective effect. Thus, glutathione conjugation at the CP epithelium coupled with the basolateral efflux of the resulting metabolites form an efficient blood–CSF enzymatic barrier, which can be enhanced by pharmacologically increasing glutathione synthesis within the epithelial cells.Journal of Cerebral Blood Flow & Metabolism (2006) 26, 1165–1175. doi:10.1038/sj.jcbfm.9600267; published online 4 January 2006 [ABSTRACT FROM AUTHOR]

The choroid plexus epithelium forms the interface between the blood and the CSF. In conjunction with the tight junctions restricting the paracellular pathway, polarized specific transport systems in the choroidal epithelium allow a fine regulation of CSF-borne biologically active mediators. The highly vascularized stroma delimited by the choroidal epithelium can be a reservoir for retrovirus-infected or activated immune cells. In this work, new insight in the implication of the blood–CSF barrier in neuroinfectious and inflammatory diseases is provided by using a differentiated cellular model of the choroidal epithelium, exposed to infected T lymphocytes. We demonstrate that T cells activated by a retroviral infection, but not non-infected cells, reduce the transporter-mediated CSF-to-blood efflux of organic anions, in particular that of the potent pro-inflammatory prostaglandin PGE2, via the release of soluble factors. A moderate alteration of the paracellular permeability also occurs. We identified the viral protein Tax, oxygenated free radicals, matrix-metalloproteinases and pro-inflammatory cytokines as active molecules released during the exposure of the epithelium to infected T cells. Among them, tumour necrosis factor and interleukin 1 are directly involved in the mechanism underlying the decrease in some choroidal organic anion efflux. Given the strong involvement of CSF-borne PGE2 in sickness behaviour syndrome, these data suggest that the blood–CSF barrier plays an important role in the pathophysiology of neuroinflammation and neuroinfection, via changes in the transport processes controlling the CSF biodisposition of PGE2. [ABSTRACT FROM AUTHOR]

Background: Macrophages, osteoclasts, dendritic cells, and microglia are highly specialized cells that belong to the mononuclear phagocyte system. Functional and phenotypic heterogeneity within the mononuclear phagocyte system may reveal differentiation plasticity of a common progenitor, but developmental pathways leading to such diversity are still unclear. Results: Mouse bone marrow cells were expanded in vitro in the presence of Flt3-ligand (FL), yielding high numbers of non-adherent cells exhibiting immature monocyte characteristics. Cells expanded for 6 days, 8 days, or 11 days (day 6-FL, day 8-FL, and day 11-FL cells, respectively) exhibited constitutive potential towards macrophage differentiation. In contrast, they showed time-dependent potential towards osteoclast, dendritic, and microglia differentiation that was detected in day 6-, day 8-, and day 11-FL cells, in response to M-CSF and receptor activator of NFκB ligand (RANKL), granulocyte-macrophage colony stimulating-factor (GM-CSF) and tumor necrosis factor-α (TNFα), and glial cell-conditioned medium (GCCM), respectively. Analysis of cell proliferation using the vital dye CFSE revealed homogenous growth in FL-stimulated cultures of bone marrow cells, demonstrating that changes in differential potential did not result from sequential outgrowth of specific precursors. [ABSTRACT FROM AUTHOR]

Abstract Anti-CV2 autoantibodies have recently been discovered in patients with paraneoplastic neurological diseases (PND). These disorders are associated with neuronal degeneration, mediated by autoimmune processes, in patients with systemic cancer. Anti-CV2 autoantibodies recognize a brain protein of 66 kDa developmentally regulated and specifically expressed by a subpopulation of oligodendrocytes in the adult brain. Here, we demonstrate that anti-CV2 sera recognize several post-translationally modified forms of Ulip4/CRMP3, a member of a protein family related to the axonal guidance and homologous to the Unc-33 gene product in Caenorhabditis elegans. The sequence of the human Ulip4/CRMP3 was determined and the gene localized to chromosome 10q25.2–q26, a region mutated in glioblastomas and containing tumour suppressor genes. The identification of the Ulip/CRMP proteins as recognized by anti-CV2 sera should provide new insights into the role of Ulip/CRMPs in oligodendrocytes and into pathophysiology of PND. [ABSTRACT FROM AUTHOR]

We studied the effect of the treatment of a medulloblastoma cell line by human T cells derived soluble factors. Medulloblastoma is one of the more common aggressive solid neoplasms in children for which there is no adequate therapy. Cell lines established from such tumours may be helpful to test the effect of various molecules on cell proliferation. Previous studies have suggested that T cell-derived factors may be toxic for the medulloblastoma cell line Dev. Cytokines were thought to mediate this effect. In this paper, we described changes in morphology, survival and cell cycle induced in Dev cells cocultured with human T cell lines chronically infected with a retrovirus (HTLV-I) and known to secrete high level of cytokines TNFα, IL1α and IL6. Such cocultures resulted in the death of a part of Dev cells and in decreased proliferation of surviving cells, associated with morphological changes and increase in vimentin expression. Treatment with conditioned medium from infected Dev cells, containing virus induced cytokines, triggered the same effect. Reduction of these effects by TNFα deprivation of conditioned medium suggested that this cytokine may be implicated. Direct treatment of Dev cells with recombinant cytokines indicated that TNFα, but not IL1 or IL6, is associated with Dev cell alterations. TNFα was shown to induce the death of Dev cells by an apoptotic pathway. Furthermore, TNFα had a bimodal effect on the cell cycle of surviving Dev cells. These differential effects of such cytokines on medulloblastoma cells could be therefore of interest for immunotherapy of these tumours. [ABSTRACT FROM AUTHOR]

Ornithine decarboxylase activity was increased about tenfold in adrenal glands and in brain regions preponderantly containing aminergic neurons, by a single dose of 16 μmol/kg of reserpine. Maximal enzyme activity in the adrenal glands was observed at about 8 hr after reserpine administration. The ornithine decarboxylase activity-time curves in the brain regions showed a concomitant polyphasic course, with the highest maximum at 12 hr postinjection. Ornithine decarboxylase induction is discussed as an early event in the cascade of molecular events preceding the induction of cell typic enzymes. [ABSTRACT FROM AUTHOR]

The existence of low and high affinity systems for tryptophan and tyrosine uptake by synaptosomes were demonstrated in vitro in the rat mesencephalon. [ABSTRACT FROM AUTHOR]

Collapsin response mediator proteins (CRMPs) are highly expressed in the brain during early postnatal development and continue to be present in specific regions into adulthood, especially in areas with extensive neuronal plasticity including the hippocampus. They are found in the axons and dendrites of neurons wherein they contribute to specific signaling mechanisms involved in the regulation of axonal and dendritic development/maintenance. We previously identified CRMP3's role on the morphology of hippocampal CA1 pyramidal dendrites and hippocampus-dependent functions. Our focus here was to further analyze its role in the dentate gyrus where it is highly expressed during development and in adults. On the basis of our new findings, it appears that CRMP3 has critical roles both in axonal and dendritic morphogenesis of dentate granular neurons. In CRMP3-deficient mice, the dendrites become dystrophic while the infrapyramidal bundle of the mossy fiber shows aberrant extension into the stratum oriens of CA3. This axonal misguided projection of granular neurons suggests that the mossy fiber-CA3 synaptic transmission, important for the evoked propagation of the activity of the hippocampal trisynaptic circuitry, may be altered, whereas the dystrophic dendrites may impair the dynamic interactions with the entorhinal cortex, both expected to affect hippocampal function. [ABSTRACT FROM AUTHOR]