A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Plasminogen activator and collagenase production by cultured capillary endothelial cells

Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.     

Separation of dissociated thyroid follicular and parfollicular cells: association of serotonin binding protein with parafollicular cells

Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported.     

Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Novel non-peptidic neuropeptide Y Y2 receptor antagonists

Through SAR studies of a piperidinylindoline cinnamide HTS lead, the first potent, non-peptide, low molecular weight selective Neuropeptide Y Y2 (NPY Y2) antagonists have been synthesized. The SAR studies around the piperidinyl, the indolinyl, and the cinnamyl moieties are discussed.     

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

Opposite Effects of Mn(III) and Fe(III) Forms of meso-Tetrakis(4-N-methyl pyridiniumyl) Porphyrins on Isolated Rat Liver Mitochondria

The relevance of porphyrins as therapeutic drugs targeted to mitochondria has been widely recognized. In this work, we studied the action of meso-tetrakis porphyrins (TMPyP) on respiring rat liver mitochondria. Mn(III)TMPyP exerted a protective effect against lipid peroxidation induced by Fe(II) or the azo initiator 4,4-azobis(4-cyanopentanoic acid) (ABCPA), which partition in the hydrophobic phospholipid moiety, and 2,2-azobis(2-amidinepropane)dihydrochloride (ABAP), which partitions in the aqueous phase. In contrast, Fe(III)TMPyP itself induced an intense lipid peroxidation, accompanied by mitochondrial permeability transition. Both mesoporphyrins studied promoted a release of mitochondrial state-4 respiration, in the concentration range of 1.0–20 M. Based on the relative effects of Mn(III)TMPyP against ABAP and ABCPA-induced lipid peroxidation, we believe that meso-tetrakis porphyrins must concentrate preferably at membrane–water interfaces.     

Characterization of a Rab11 homologue in Trypanosoma cruzi

Vesicle trafficking between organelles occurs through fusion of donor and specific acceptor membranes. This process is highly regulated and ensures proper direction in sorting and packaging of a number of molecules in eukaryotic cells. Monomeric GTPases of the Rab family play a pivotal role in the control of membrane fusion and vesicle traffic. In this paper, we characterize a Trypanosoma cruzi Rab 11 homologue (TcRab11) that shares at, the amino acid level, 40% similarity with human rab11, Arabdopsis thaliana rab11 and yeast rab11 homologue genes. Western blot analysis, using a polyclonal rabbit antiserum raised against a synthetic peptide derived from the COOH-terminus of predicted the TcRab11 protein, reacted to a 26kDa protein. In immunofluorescence assays, TcRab 11, was shown to be expressed in epimastigote and amastigote forms, but it was absent in trypomastigotes. Interestingly, the TcRab11 product seems to be located at the reservosome complex, a site of active endocytosis and vesicle fusion present only in the epimastigote stage. Therefore, TcRab11 may represent the first molecular marker of this peculiar organelle.