IPS-1 Is Essential for the Control of West Nile Virus Infection and Immunity

The innate immune response is essential for controlling West Nile virus (WNV) infection but how this response is propagated and regulates adaptive immunity in vivo are not defined. Herein, we show that IPS-1, the central adaptor protein to RIG-I-like receptor (RLR) signaling, is essential for triggering of innate immunity and for effective development and regulation of adaptive immunity against pathogenic WNV. IPS-1^−/− mice exhibited increased susceptibility to WNV infection marked by enhanced viral replication and dissemination with early viral entry into the CNS. Infection of cultured bone-marrow (BM) derived dendritic cells (DCs), macrophages (Macs), and primary cortical neurons showed that the IPS-1-dependent RLR signaling was essential for triggering IFN defenses and controlling virus replication in these key target cells of infection. Intriguingly, infected IPS-1^−/− mice displayed uncontrolled inflammation that included elevated systemic type I IFN, proinflammatory cytokine and chemokine responses, increased numbers of inflammatory DCs, enhanced humoral responses marked by complete loss of virus neutralization activity, and increased numbers of virus-specific CD8+ T cells and non-specific immune cell proliferation in the periphery and in the CNS. This uncontrolled inflammatory response was associated with a lack of regulatory T cell expansion that normally occurs during acute WNV infection. Thus, the enhanced inflammatory response in the absence of IPS-1 was coupled with a failure to protect against WNV infection. Our data define an innate/adaptive immune interface mediated through IPS-1-dependent RLR signaling that regulates the quantity, quality, and balance of the immune response to WNV infection.     

Sympathetic control of cerebral arteries: specialization in receptor type, reserve, affinity, and distribution

The sympathetic neuroeffector system in the mammalian cerebral circulation has a number of distinctive features that reflect its specialized role in this vascular bed: 1) there is limited alpha-adrenoceptor-mediated contraction in large vessels that becomes progressively less important with branching; 2) contraction is limited by receptor number; small branches often seem to have no functional alpha adrenoceptors; 3) adrenoceptor affinity for norepinephrine is low and so is sensitivity; and 4) the dominant alpha-adrenoceptor subtype differs in different species and may have unique characteristics in some. There is a mechanism of non-alpha-adrenoceptor-mediated contraction involving low-affinity receptor sites--extraceptors--activated by sympathetic nerves. The pig has a seemingly atypical sympathetic mechanism. On the basis of current information the sympathetic neuroeffector mechanisms of the rabbit seem most clearly related to the human. The size, pattern, and distribution of sympathetic control suggest that the role of the sympathetic nerves is to protect the smaller pial arteries against the consequences of sudden increases in sympathetic adrenal discharge. It is not an important mechanism of controlling cerebral blood flow.     

Transport of a carcinogen, benzo[a]pyrene, from particulates to lipid bilayers: a model for the fate of particle-adsorbed polynuclear aromatic hydrocarbons which are retained in the lungs

DNA from Ehrlich ascites tumor cells is nicked or gapped by a reaction which is induced by proteases such as autodigested pronase, proteinase K, trypsin, chymotrypsin and subtilisin. The cleavage of the protease-sensitive sites is inhibited by protease inhibitors. The nicks or gaps induced by proteases can be demonstrated by nuclease S1 sensitivity of native DNA and by a change of the sedimentation rate of alkali-denatured DNA. The limit size of denatured DNA released after optimal protease treatment is 8.5 x 10(6) daltons (27 kilo bases). The molecular weight of the native DNA pieces released after nuclease S1 degradation of DNA containing the protease-induced nicks or gaps is in the same order indicating that the protease-sensitive sites are alternatively arranged on the opposite DNA strands at an average distance of 13.5 kilo base pairs. Since the protease-induced nicks or gaps in phosphatase-treated DNA are not attacked by Escherichia coli polymerase I, one or both ends liberated by the protease treatment must be blocked by a material other than phosphate groups. The results are most compatible with peptide/protein linkers joining adjacent single-strand DNA subunits. Alternative explanations such as alkali-stable RNA linkers, protein-protected RNA linkers, site-specific nuclease contaminations in the protease preparations or cellular nucleases activated by the protease treatment are eliminated by the results presented in this paper.     

How can we inhibit 5-HT-induced platelet aggregation and why should we bother?

Different 5-HT receptor antagonists inhibit 5-HT-induced platelet aggregation with different potencies. The inhibitory effects of seven relatively potent antagonists could not be surmounted by increasing the concentration of 5-HT, but the inhibitory effects of seven less potent antagonists could be surmounted by 5-HT. Verapamil has in insurmountable inhibitory effect on 5-HT-induced aggregation at relatively low concentrations. Amlodipine is a very weak inhibitory of 5-HT-induced aggregation. Verapamil is more effective as an inhibitory of 5-HT-induced aggregation than it is of aggregation induced by PAF, adrenaline or ADP. The platelet aggregation obtained in whole blood in response to 5-HT, PAF, U46619 or ADP is not different in patients with peripheral vascular disease and age-sex matched controls.     

Differential expression within a family of novel wound-induced genes in potato

Summary Wounding in higher plants leads to an increased synthesis of specific messenger RNAs. A cDNA clone complementary to a wound-induced message from potato tubers was used to isolate a lambda clone from a genomic library of Salanum tuberosum var. Maris Piper. DNA sequence analysis has shown that this single genomic clone contains two novel wound-induced genes, called win1 and win2, organised in close tandem array. The coding sequences of these two genes are highly homologous and are interrupted by a single intron. However, the sequences of the introns and flanking regions have diverged widely. Win1 and win2 encode cysteine-rich proteins of 200 and 211 amino-acids, respectively, which show striking homologies to several chitin-binding proteins. Southern analysis of genomic DNA has shown that win1 and win2 are members of a small multi-gene family which is estimated to have a minimum of five members per haploid genome of Maris Piper and appears to be conserved within the Solanaceae. We have shown by Northern analysis and S1 mapping that the two genes exhibit differential organ-specific expression after the wounding of a potato plant.     

Presence of a Na+/H+ exchanger in brush border membranes isolated from the kidney of the spiny dogfish,Squalus acanthias

Summary A membrane fraction, rich in brush border membranes, was prepared from renal proximal tubules of the spiny dogfish,Squalus acanthias, and the sodium-proton exchange mechanism in these membrane vesicles was investigated by both a rapid filtration technique and the fluorescence quenching of acridine organe.²²Na⁺ uptake was stimulated by an outwardly directed H⁺ gradient, and was inhibited by amiloride at a single inhibitory site with an apparentK _i of approximately 1.7×10^–5 M. In the presence of an H _i ⁺ >H _o ⁺ gradient, the of the Na⁺/H⁺ exchanger were 9.7±0.8 mM and 48.0±12.0 nmol·mg protein^–1·min^–1, respectively. The uptake of Na⁺ was electroneutral in the presence of a H⁺ gradient, indicating a stoichiometry of 1. In the fluorescence studies, quenching of acridine orange occurred in the presence of an outwardly directed Na⁺ gradient which was inhibited by amiloride. Thus, an electroneutral Na⁺/H⁺ exchanger with properties similar to those found in the mammalian kidney is also present in the spiny dogfish and may contribute to the urinary acidification of this marine animal.