Halofuginone does not reduce fibrosis in bleomycin-induced lung injury

Halofuginone, a coccidiostatic alkaloid, has anti-fibrotic properties, and may be useful as a therapeutic agent in lung fibrosis. To test this hypothesis we investigated the effect of halofuginone on bleomycin-induced lung fibrosis in Sprague-Dawley rats. Treatment groups included: (1) a single intratracheal (IT) instillation of 1.2U bleomycin, and intraperitoneal (IP) injection of halofuginone (0.5 mg/dose), every other day; (2) IT 1.2U bleomycin and IP distilled water (D.W.), every other day; (3) IT 0.8U bleomycin and daily IP halofuginone (0.5 mg/dose); (4) IT 0.8U bleomycin and daily IP D.W.; (5) IT saline and IP halofuginone, every other day; (6) IT saline and daily IP D.W.; (7) IT 0.625U bleomycin and oral halofuginone (10 mg/kg rodent lab chow); (8) IT 0.625U bleomycin and standard lab chow. Animals were studied 14 days after IT instillation. Lung injury was evaluated by total and differential cell count in bronchoalveolar lavage fluid, by a semi-quantitative morphological index of lung injury, and by biochemical analysis of lung hydroxyproline content. Overt signs of lung injury were apparent in bleomycin-treated rats by all measures. These changes were not affected by treatment with halofuginone, irrespective of the treatment regimen used. This study does not support the use of halofuginone to prevent or ameliorate lung fibrosis.     

A single-chain class II MHC-IgG3 fusion protein inhibits autoimmune arthritis by induction of antigen-specific hyporesponsiveness

T cells play a central role in many autoimmune diseases. A method to specifically target the function of autoreactive T cell clones would avoid the global immunosuppression associated with current therapies. To develop a molecule capable of inhibiting autoreactive T cell responses in vivo, single-chain peptide-I-A-IgG3 fusion proteins were constructed and expressed in both mammalian and insect cells. The fusion proteins were designed with an IgG3 Fc moiety to make them divalent, allowing TCR cross-linking, while lacking FcR binding and costimulation. The fusion proteins stimulated T cell hybridomas in vitro in a peptide-specific, MHC-restricted manner but failed to do so in soluble form. In vivo administration of an I-A(q) fusion protein, containing an immunodominant collagen II peptide, significantly delayed the onset and reduced the severity of collagen-induced arthritis in DBA/1 mice by induction of Ag-specific hyporesponsiveness. Such fusion proteins may be useful to study novel therapeutic approaches for T cell-mediated autoimmune diseases.     

Water deficit during root development: effects on the growth of roots and osmotic water permeability of isolated root protoplasts

The effect of low water potentials on root growth of flax (Linum usitatissimum L. cv. Ariane), rape (Brassica napus L. de Candolle, cv. Bristol), hard wheat (Triticum turgidum L. cv. Cham1) and soft wheat (Triticum aestivum L. cv. Ritmo) was studied by measuring the osmotic water permeability (Pos) of root protoplasts and the protein abundance of PIP1 and PIP2 aquaporins. These different species require more or less water, the most sensitive to water deficit being flax and rape. Ritmo, is a cultivar of wheat adapted to temperate zones, while the other cultivar Cham1 is adapted to low-rainfall areas. The seedlings were germinated and grown in water, salt or sugar solutions at different water potentials. The values of Pos for flax, rape and Chaml wheat were normally distributed and could be characterized by mean +/- SD. Root protoplasts from water-grown seedlings had Pos values of 485+/-159 microm s(-1) (flax), 582+/-100 microm s(-1) (rape), and 6.3+/-3.5 microm s(-1) (Cham1). At the same age, the protoplasts from Ritmo exhibited a much wider range of values than the protoplasts of Cham1. When seedlings were grown under conditions of osmotic or salt stress, the mass of the roots was reduced for all species. With 0.25 mol kg(-1) sorbitol or 0.125 M NaCl, the Pos for flax, rape and Cham1 remained constant or slightly increased, while for Ritmo the reduction in the mass of the roots was paralleled by a reduction in Pos. Only Cham1 and Ritmo were able to germinate at a lower potential (0.5 mol kg(-1) sorbitol). For Ritmo the reduction in the mass of the roots was paralleled by a reduction in Pos when grown in this stress condition and both wheats exhibited low Pos values. The expression of the PIP1 and PIP2 aquaporins families was also studied by immunoblotting. We did not observe any difference in protein expression for any of the species, whatever the growing conditions. We suggest that the high Pos values for flax and rape could play a role in the sensitivity of these plants at low water potential. The low native Pos for Cham1 in spite of the expression of both families of aquaporins may reflect its adaptation to low-rainfall conditions by a functional regulation of the water channels. For a similar reason, the low-water-potential-induced Pos of Ritmo may also correspond to a down-regulation of the aquaporins, reflecting adaptation of this wheat to water-deficit conditions.     

Energy estimation in protein design

The progress achieved by several groups in the field of computational protein design shows that successful design methods include two major features: efficient algorithms to deal with the combinatorial exploration of sequence space and optimal energy functions to rank sequences according to their fitness for the given fold.     

Oncostatin M induces tissue-type plasminogen activator and plasminogen activator inhibitor-1 in Calu-1 lung carcinoma cells

Oncostatin M (OSM) is a glycoprotein cytokine that is produced by activated T-lymphocytes, monocytes, and macrophages. In a DNA synthesis assay, OSM reduced tritiated thymidine incorporation by 53% in Calu-1 lung carcinoma cells. Radiolabeled cDNAs from untreated Calu-1 cells and 30-h OSM-treated cells were used to probe duplicate nylon membrane cDNA expression arrays. This study revealed OSM-mediated expression of mRNAs encoding tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). Northern blot analysis showed that the steady-state level of tPA mRNA is nearly undetectable in Calu-1 cells. Exposure of these cells to OSM for 30 h increased tPA mRNA expression by 20-fold and PAI-1 mRNA expression by 5-fold. Exposure of these cells to other gp130 receptor family cytokines, including leukemia inhibitory factor (LIF), interleukin-6 (IL-6), and IL-11, do not significantly affect DNA synthesis or induction of tPA/PAI-1. Western blot studies demonstrated that OSM mediates a marked increase in secretion of the tPA protein. Secreted tPA was present in the conditioned medium almost exclusively as tPA/PAI-1 complexes. Inhibitor studies demonstrated that OSM-mediated induction of tPA and PAI-1 mRNAs is largely dependent upon activation of the MEK1/2 pathway. The JAK3/STAT3 pathway potentially serves a secondary role in these regulatory events.     

Machine scoring of Her2/neu immunohistochemical stains

OBJECTIVE: To establish the feasibility of a machine scoring method for her2/neu immunohistochemistry in samples of breast carcinoma. STUDY DESIGN: A total of 65 consecutive cases of breast carcinoma with immunohistochemical stainingfor her2/neu by the Herceptest (Dako Corp., Carpinteria, California, U.S.A.) method (DAB chromogen with hematoxylin counterstain) were analyzed using an Extended Slide Wizard (Tripath Imaging, Inc., Burlington, North Carolina, U.S.A.) workstation running prototype software. Representative fields of view from the positive control, negative control and up to 10 fields from the stained tumor sample were captured interactively with a phased alternating line 3 CCD color camera. To determine the amount of specific membrane staining, chromogen separation of nuclear counterstain and membrane-positive stain was performed based on their respective absorption coefficients in the three color channels. The amount of specific membrane staining was scored based on a training set covering the rangefrom 0 to 3 + staining scores according to Dako. Manual scores of 2 + were tested for amplification by fluorescence in situ hybridization. RESULTS: The automated scoring results correlated highly with the manual scores obtained per the Herceptest (Dako) instructions (R2>.92). The results were obtained in real time in the interactive mode. CONCLUSION: Machine scoring of immunohistochemical stains is practical, rapid and inherently reproducible, especially for samples with 1+ and 2+ manual scores.     

Flavonoids of Ochna afzelii

Fractionation of the methanolic extract of Ochna afzelii stem bark has resulted in the isolation of two biflavonoids afzelones A and B along with five known flavonoids, calodenins A and B, afzelone C, 4',5-dimethoxy-6,7-methylenedioxyisoflavone, 4',5,7-trimethoxyisoflavone and the glucoside lanceoloside A. Their structures were determined using spectroscopic and chemical methods.     

Plasma membrane aquaporins are involved in winter embolism recovery in walnut tree

In perennial plants, freeze-thaw cycles during the winter months can induce the formation of air bubbles in xylem vessels, leading to changes in their hydraulic conductivity. Refilling of embolized xylem vessels requires an osmotic force that is created by the accumulation of soluble sugars in the vessels. Low water potential leads to water movement from the parenchyma cells into the xylem vessels. The water flux gives rise to a positive pressure essential for the recovery of xylem hydraulic conductivity. We investigated the possible role of plasma membrane aquaporins in winter embolism recovery in walnut (Juglans regia). First, we established that xylem parenchyma starch is converted to sucrose in the winter months. Then, from a xylem-derived cDNA library, we isolated two PIP2 aquaporin genes (JrPIP2,1 and JrPIP2,2) that encode nearly identical proteins. The water channel activity of the JrPIP2,1 protein was demonstrated by its expression in Xenopus laevis oocytes. The expression of the two PIP2 isoforms was investigated throughout the autumn-winter period. In the winter period, high levels of PIP2 mRNA and corresponding protein occurred simultaneously with the rise in sucrose. Furthermore, immunolocalization studies in the winter period show that PIP2 aquaporins were mainly localized in vessel-associated cells, which play a major role in controlling solute flux between parenchyma cells and xylem vessels. Taken together, our data suggest that PIP2 aquaporins could play a role in water transport between xylem parenchyma cells and embolized vessels.