We previously reported that the anti-inflammatory cytokine interleukin (IL)-4 induced selective clearance of oligomeric β-amyloid (Aβ(1-42)) in rat primary type 2 microglial cells. For the present study, we investigated whether IL-4 and IL-13 could activate microglial cells to induce Aβ clearance in vivo and improve cognitive deficits in APP23 mice, which are amyloid precursor protein transgenic mice. We administered an intracerebral microinjection of a mixture of IL-4 and IL-13 or of saline vehicle into one hemisphere of APP23 mice and their wild-type littermates, 4.5 and 9 months old, after which we evaluated the effects of these treatments on spatial learning and memory by Morris Water Maze test and on accumulated amounts of Aβ. The cytokine injection significantly improved memory deficits of 4.5-month-old APP23 mice, but did not do so in 9-month-old APP23 mice, even though similar Aβ reductions were observed in both age groups of APP23 mice in the ipsilateral neocortex. The cytokine injection improved memory impairment of 9-month-old wild-type (WT) mice in the probe trial. Immunohistochemical analysis of the 4.5-month-old APP23 mice revealed the presence of increased numbers of microglial cells at 2 days after the cytokine injection. In addition to induced CD36 expression in the activated microglia, increased expression of neprilysin, mainly in neurons, suggested that the cytokines improved the cognitive deficits via degradation and clearance of intra- and extraneuronal Aβ peptides, of buffer-extractable nonplaque form. Double immunostaining also revealed that most of the activated microglia had the M2-like phenotype. This unique mechanism of IL-4/IL-13-induced clearance of Aβ may provide an additional strategy to prevent and/or cure Alzheimer's disease at early stage.

The primary structure of nucleoside diphosphate (NDP) kinase II, one of the two isozymes found in spinach leaves, has been deduced from its cDNA sequence. NDP kinase II comprises 233 amino acid residues and has a molecular mass of 26,107 Da, which is larger than that of the purified NDP kinase II subunits (18 kDa) by about 8 kDa, suggesting that NDP kinase II might be post-translationally processed. Homology was found between the sequence of spinach NDP kinase II, and the sequences of spinach NDP kinase I, rat NDP kinases alpha and beta, Dictyostelium discoideum NDP kinase, the human Nm23-H1 and Nm23-H2 proteins and the awd protein of Drosophila melanogaster.

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Bovine Mx2 gene sequences were already reported, but further information about the gene properties is not yet available. The objective of the current study was to elucidate the structural properties of the bovine Mx2 gene mainly the promoter region and its possible functional role. If available, such information would help in assessing the functional properties of the gene, which was reported to confer antiviral action against recombinant VSV.

We have evaluated the bactericidal activity of hen ovotransferrin (OTf), which was found to operate regardless of its iron-deprivation properties, with the objective of isolating the bactericidal domain. The amino-terminal half-molecule (N-lobe, residues 1-332) of OTf, isolated by trypsin-nicking, retained the bactericidal activity independently of iron-deprivation, but not the carboxyl-terminal half-molecule (C-lobe, residue 342-686), suggesting the presence of a bactericidal domain within the N-lobe of the molecule. Specific cleavage at the aspartyl residues of OTf, by diluted-acid procedure, yielded fairly large peptides, whereas proteolysis for 150 min produced the strongest bactericidal peptides mixture. The bactericidal domain was purified from the active hydrolysate by gel filtration and reversed-phase HPLC and showed activity against S. aureus as well as E. coli K-12. Electrophoretic analysis on tricine-SDS-PAGE revealed a bactericidal peptide with an average M(r) of 9900 Da under non-reducing conditions. In combination with the specificity of cleavage (Asp-X) and the molecular mass, its N-terminal microsequencing corresponded to a cationic peptide consisting of 92 residues located within the 109-200 sequence of the N-lobe of OTf, containing three intrachain disulfide bridges, featuring a common structural motif occurs in the N-lobes of transferrins for which the sequence is available. Two of the disulfides (C160-C174 and C171-C182) form surface exposed cringle bridges lying on the opposite side of the iron-binding site from the interdomain cleft and showing marked sequence homology to insect defensins, which are blockers of the voltage-dependent K+ channels. The peptide lost antibacterial activity when its disulfide bonds were reduced, indicating the importance of its tertiary structure for the exertion of antibiotic activity.