Brain Shuttle Neprilysin reduces central Amyloid-ß levels.

Reducing Amyloid ß (Aß) in the brain is of fundamental importance for advancing the therapeutics for Alzheimer`s disease. The endogenous metallopeptidase neprilysin (NEP) has been identified as one of the key Aß-degrading enzymes. Delivery of NEP to the brain by utilizing the Brain Shuttle (BS) transport system offers a promising approach for clearing central Aß. We fused the extracellular catalytic domain of NEP to an active or inactive BS module. The two BS-NEP constructs were used to investigate the pharmacokinetic/pharmacodynamics relationships in the blood and the cerebrospinal fluid (CSF) in dose-response and multiple dosing. As previously shown, NEP was highly effective at degrading Aß in blood but not in the CSF compartment after systemic administration. In contrast, the NEP with an active BS module led to a significant CSF exposure of BS-NEP, followed by substantial Aß reduction in CSF and brain parenchyma. Our data show that a BS module against the transferrin receptor facilitates the transport of an Aß degrading enzyme across the blood-brain barriers to efficiently reduce Aß levels in both CSF and brain.

The antidepressant fluoxetine protects the hippocampus from brain damage in experimental pneumococcal meningitis.

BACKGROUND: High mortality and morbidity rates are observed in patients with bacterial meningitis (BM) and urge for new adjuvant treatments in addition to standard antibiotic therapies. In BM the hippocampal dentate gyrus is injured by apoptosis while in cortical areas ischemic necrosis occurs. Experimental therapies aimed at reducing the inflammatory response and brain damage have successfully been evaluated in animal models of BM. Fluoxetine (FLX) is an anti-depressant of the selective serotonin reuptake inhibitors (SSRI) and was previously shown to be neuroprotective in vitro and in vivo. We therefore assessed the neuroprotective effect of FLX in experimental pneumococcal meningitis. METHODS: Infant rats were infected intracisternally with live Streptococcus pneumoniae. Intraperitoneal treatment with FLX (10mgkg(-1)d(-1)) or an equal volume of NaCl was initiated 15min later. 18, 27, and 42h after infection, the animals were clinically (weight, clinical score, mortality) evaluated and subject to a cisternal puncture and inflammatory parameters (i.e., cyto-/chemokines, myeloperoxidase activity, matrix metalloproteinase concentrations) were measured in cerebrospinal fluid (CSF) samples. At 42h after infection, animals were sacrificed and the brains collected for histomorphometrical analysis of brain damage. RESULTS: A significant lower number of animals treated with FLX showed relevant hippocampal apoptosis when compared to littermates (9/19 animals vs 18/23, P=0.038). A trend for less damage in cortical areas was observed in FLX-treated animals compared to controls (13/19 vs 13/23, P=ns). Clinical and inflammatory parameters were not affected by FLX treatment. CONCLUSION: A significant neuroprotective effect of FLX on the hippocampus was observed in acute pneumococcal meningitis in infant rats.

Measles virus-specific plasma cells are prominent in subacute sclerosing panencephalitis CSF.

OBJECTIVE: To demonstrate the specificity of expanded CD138(+) plasma cell clones recovered from the CSF of a patient with subacute sclerosing panencephalitis (SSPE) for measles virus (MV). METHODS: IgG variable region sequences of single-antibody-secreting CD138(+) cells sorted from SSPE CSF were amplified by single-cell PCR and analyzed. Human IgG1 recombinant antibodies (rAbs) were produced from four expanded CD138(+) clones and assayed for immunoreactivity against MV proteins. RESULTS: Clonal expansion was a prominent feature of the SSPE plasma cell repertoire, and each of the four rAbs assayed was specific for either the MV fusion or the MV nucleocapsid protein. CONCLUSIONS: Expanded plasma cell clones in the CSF of patients with subacute sclerosing panencephalitis produce disease-relevant antibodies. Recombinant antibodies derived from CSF B cells could provide a tool to identify target antigens in idiopathic inflammatory disorders.

New neurons follow the flow of cerebrospinal fluid in the adult brain.

In the adult brain, neuroblasts born in the subventricular zone migrate from the walls of the lateral ventricles to the olfactory bulb. How do these cells orient over such a long distance and through complex territories? Here we show that neuroblast migration parallels cerebrospinal fluid (CSF) flow. Beating of ependymal cilia is required for normal CSF flow, concentration gradient formation of CSF guidance molecules, and directional migration of neuroblasts. Results suggest that polarized epithelial cells contribute important vectorial information for guidance of young, migrating neurons.

Elevated concentration of N-CAM VASE isoforms in schizophrenia.

Neural cell adhesion molecule (N-CAM) is a cell recognition molecule, four major isoforms (180, 140, 120, and 105-115 kDa) of which are present in brain. N-CAM has several roles in cellular organization and CNS development. Previously we have found an elevation in CSF N-CAM 120 kDa in the CSF of patients with schizophrenia, bipolar disorder, and depression. We now report an increase in the variable alternative spliced exon (VASE), a 10 amino acid sequence inserted into the fourth N-CAM domain, in the CSF of patients with schizophrenia, but not in bipolar disorder or depression. VASE-immunoreactive (VASE-ir) bands were measured in CSF from patients with schizophrenia (n = 14), bipolar disorder I (n = 7), bipolar disorder II (n = 9), unipolar depression (n = 17) and matched controls (n = 37) by Western immunoblotting. Three VASE-ir bands were distinguished in lumbar CSF corresponding to heavy (165 kDa), medium (155 kDa) and low (140 kDa) MW. A logarithmic transformation was applied to the VASE protein units and analyzed with a MANOVA. There was a 51% and 45% increase in VASE heavy (p = 0.0008) and medium (p = 0.04) MW protein, respectively, in patients with schizophrenia as compared with normal controls. Current neuroleptic treatment in patients with schizophrenia had no effect on CSF VASE concentrations. VASE concentration correlated significantly with behavioral ratings in patients with schizophrenia but not affective disorders. Thus, VASE immunoreactivity is increased in schizophrenia but not in affective disorders. These results provide further evidence of an abnormality of N-CAM protein in chronic schizophrenia and suggest differences between schizophrenia and affective disorders in regulation of N-CAM.