FIZZ1, a novel cysteine-rich secreted protein associated with pulmonary inflammation, defines a new gene family.

Bronchoalveolar lavage fluid from mice with experimentally induced allergic pulmonary inflammation contains a novel 9.4 kDa cysteine-rich secreted protein, FIZZ1 (found in inflammatory zone). Murine (m) FIZZ1 is the founding member of a new gene family including two other murine genes expressed, respectively, in intestinal crypt epithelium and white adipose tissue, and two related human genes. In control mice, FIZZ1 mRNA and protein expression occur at low levels in a subset of bronchial epithelial cells and in non-neuronal cells adjacent to neurovascular bundles in the peribronchial stroma, and in the wall of the large and small bowel. During allergic pulmonary inflammation, mFIZZ1 expression markedly increases in hypertrophic, hyperplastic bronchial epithelium and appears in type II alveolar pneumocytes. In vitro, recombinant mFIZZ1 inhibits the nerve growth factor (NGF)-mediated survival of rat embryonic day 14 dorsal root ganglion (DRG) neurons and NGF-induced CGRP gene expression in adult rat DRG neurons. In vivo, FIZZ1 may modulate the function of neurons innervating the bronchial tree, thereby altering the local tissue response to allergic pulmonary inflammation.

Monomeric variants of IL-8: effects of side chain substitutions and solution conditions upon dimer formation.

IL-8 dimers have been observed in NMR and X-ray structures of the protein. We have engineered IL-8 monomers by mutations of residues throughout the dimer interface, which introduce hindrance determinants to dimerization. These IL-8 variants are shown by NMR to have wild-type monomer folding, but by ultracentrifugation to have a range of dimerization constants from microM to mM, as compared with a dimerization constant of about 10 microM for wild-type IL-8, under physiological salt and temperature conditions. The monomeric variants of IL-8 bind the erythrocyte chemokine receptor DARC, as well as the neutrophil IL-8 receptors CXCR1 and CXCR2 with affinities similar to that of wild-type IL-8. In addition, the monomeric variants were shown to have agonist activity, with similar potency to wild-type, in both Ca(2+)-flux assays on CXCR1 and CXCR2 transfected cells, and in chemotaxis assays on neutrophils. Thus, these variants confirm that monomeric IL-8 is functionally equivalent to wild-type in vitro assays. We have also investigated the effects of various solution conditions upon IL-8 dimer formation using analytical ultracentrifugation. At salt concentrations, temperatures, and pH conditions lower than physiological, the dimerization affinity of IL-8 is greatly enhanced. This suggests that, under some conditions, IL-8 dimer formation may occur at concentrations of IL-8 considerably lower than 10 microM, with consequences in vivo that are yet to be determined.

Small extrachromosomal nucleic acid segments in protozoan parasites.

Viruses have been described in the following protozoa: Babesia spp., Trichomonas vaginalis, Giardia lamblia, Leishmania braziliensis and Eimeria spp. In order to study the Babesia bovis virus, merozoites have been prepared from the blood of infected cattle. Agarose gel electrophoresis of nucleic extracts from the bovine protozoa B. bovis and Babesia bigemina were separated into genomic DNA and at least two additional nucleic acids. One molecule with a relative mobility of 5.5 kilobase pairs (kbp) was identified as a double-stranded RNA virus-like particle. Another 6.2 kbp DNA molecule had sequences related to mitochondrial genome.

Complete mutagenesis of the extracellular domain of interleukin-8 (IL-8) type A receptor identifies charged residues mediating IL-8 binding and signal transduction.

We systematically converted each of the amino acids in the extracellular domain of the interleukin-8 (IL-8) type A receptor to alanine for the purpose of identifying amino acids contributing to IL-8 binding and IL-8-mediated signal transduction. We identified 20 mutations which cause a decrease in receptor affinity from a Kd of 2 nM to a Kd > or = 25 nM. We then analyzed these receptor mutants for their ability to mobilize intracellular calcium upon stimulation with 10 nM IL-8. The majority of the mutants were able to produce calcium fluxes at levels approximating that of wild-type IL-8 receptor A, with the exception of six mutants (R199A, R203A, C30A, C110A, C187A, and C277A) which showed no significant response. In addition, we performed calcium mobilization experiments to further characterize a series of previously constructed mutants which had only been characterized by their binding affinities in our previous report and found that mutant D265A showed no response upon stimulation with 10 nM IL-8. Our study shows that, besides the extracellular domain cysteines which may be critical for the overall folding of the receptor, three residues, Arg-199, Arg-203, and Asp-265, are important for IL-8 binding and IL-8-mediated signal transduction.

The assessment of personality characteristics in depressed and dependent psychiatric inpatients.

The diagnosis and treatment of depression may be complicated by the presence of excessive dependency needs. Previous research has found stable personality traits useful in identifying depressive subtypes. This study was designed to assess the personality characteristics of 106 psychiatric inpatients. Subjects were grouped according to the presence or absence of two primary dimensions: depression and dependency. Results indicated that both depression and dependency were significantly related to various indices of psychopathology. Main effects were more useful than interactions, implying that depression and dependency both affect symptomology directly rather than interactively. Although the assessment of personality traits may be complicated by the presence of a major psychiatric disorder, results from our study suggest that the assessment of both Axis I and Axis II variables can be useful in understanding the current clinical picture.