Oncostatin M and transforming growth factor-beta 1 induce post-translational modification and hyaluronan binding to CD44 in lung-derived epithelial tumor cells

CD44, a receptor for hyaluronan (HA), has been implicated in tumor growth and metastasis. Most CD44-positive cells fail to exhibit constitutive HA receptor function but CD44-mediated HA binding on hematopoetic cells can be induced by antibody cross-linking of the receptor and by physiologic stimuli, including cytokines. We now demonstrate that oncostatin M (OSM) and transforming growth factor-beta1, cytokines known to regulate the growth of tumor cells, stimulate HA binding in lung epithelial-derived tumor cells. In lung epithelial-derived tumor cells, cytokine-induced binding resulted from post-translational modification of the receptor. OSM-induced HA binding was associated with a reduction in N-linked carbohydrate content of CD44. In addition, OSM induced HA binding via a novel mechanism requiring sulfation of chondroitin sulfate chains linked to CD44. The mechanism underlying transforming growth factor-beta1 induced HA binding was distinct from the effects of OSM. The data presented indicate that modulation of the glycosylation and sulfation of CD44 by cytokines provides mechanisms for regulating cell adhesion during tumor growth and metastasis.     

Acute phase mediator oncostatin M regulates affinity of alpha1-protease inhibitor for concanavalin A in hepatoma-derived but not lung-derived epithelial cells

Quantitative changes in plasma protein concentrations during tissue injury or inflammation (acute phase response) are often accompanied by specific alterations in the carbohydrate moieties of these proteins. The glycosylation changes comprise alterations in the type of branching of the carbohydrate structures as revealed by modulated reactivity of acute phase glycoproteins with the lectin concanavalin A. Interestingly, inflammation-induced changes in the glycosylation of acute phase proteins have been shown to affect the functional properties of these proteins. In this study we demonstrate that synthesis of acute phase protein alpha(1)-PI, the controlling inhibitor of neutrophil elastase, is significantly up-regulated in hepatic and lung-derived epithelial cells by the inflammatory mediator oncostatin M. Although oncostatin M markedly altered the concanavalin A reactivity of hepatic alpha(1)-PI, lung-derived epithelial cells did not change the pattern of alpha(1)-PI glycan branching upon stimulation with oncostatin M. These results indicate that inflammation-induced changes in glycosylation of alpha(1)-PI may have different impacts on functional properties of liver and lung-synthesized alpha(1)-PI.     

Proteinase-mediated release of epithelial cell-associated CD44. Extracellular CD44 complexes with components of cellular matrices

CD44 is a receptor for the matrix glycosaminoglycan hyaluronan. Proteoglycan forms of CD44 also exhibit affinity for fibronectin and collagen as well as chemokines and growth factors. CD44 plays a role in autoimmunity, inflammation, and tumor progression. Soluble CD44 (sCD44) is found in plasma, and the levels of sCD44 correlate with immune function and some malignancies. The mechanisms by which sCD44 is generated and its function are unknown. We demonstrate here that normal bronchial epithelial cells spontaneously release sCD44. Exposure to phagocyte- and bacterium-derived proteinases markedly increased the release of sCD44 from epithelial cells. The spontaneously released sCD44 was incorporated into high molecular mass complexes derived from the matrix that also contained chondroitin sulfate, fibronectin, hyaluronan, and collagens I and IV. Enzymatic digestion with proteinases liberated sCD44 from the high molecular mass complex. Consistent with the homology of CD44 to proteoglycan core and link proteins, these data suggest that CD44 spontaneously released from normal bronchial epithelial cells can accumulate as an integral component of the matrix, where it may play a role in the organization of matrices and in anchoring growth factors and chemokines to the matrix. Increases in plasma CD44 during immune activation and tumor progression therefore may be a manifestation of the matrix remodeling that occurs in the face of the enhanced proteolytic activity associated with infection, inflammation, and tumor metastasis, leading to alterations in cell-matrix interactions.     

Regulation of the release and function of tumor cell-derived soluble CD44

CD44, a major receptor for glycosaminoglycan hyaluronan (HA), is a broadly distributed cell surface glycoprotein implicated in multiple functions, including tumor growth and dissemination. The affinity of surface CD44 for HA is subject to regulation at several levels. CD44 is found in multiple phases, including as an integral transmembrane protein and as soluble fragment of the extracellular domain found in the circulation and other body fluids. Transmembrane CD44 and its ability to interact with HA have been a focus of numerous studies in the past, but the function of soluble CD44 remains obscure. Interestingly, malignant diseases are often associated with an increase in the plasma level of CD44. The delineation of the HA binding capacity of tumor-derived soluble CD44 is an important step toward understanding the biological function of this molecule. In this study, we demonstrate that tumor cells activated to bind HA by cytokines rapidly release CD44 upon treatment with phorbol ester (PMA). The affinity for HA of the soluble CD44 released in response to PMA varied depending on the cytokine pretreatment. These results suggest that the function of tumor-derived soluble CD44, like the transmembrane form of the receptor, can be regulated.     

Interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor alpha (TNF alpha) regulate insulin-like growth factor binding protein-1 (IGFBP-1) levels and mRNA abundance in vivo and in vitro.

TNF alpha and IL-1 alpha are thought to contribute to impaired anabolism in a variety of clinical states, including sepsis, cancer cachexia and the AIDS wasting syndrome. We asked whether cytokines exert direct effects on hepatic production of IGFBP-1, an important modulator of IGF bioavailability. C57BL/6 mice were treated with 100 micrograms/kg of recombinant IL-1 alpha or TNF alpha by intraperitoneal injection. Western ligand blotting and immunoprecipitation with specific antisera revealed that serum levels of IGFBP-1 (but not IGFBP-2, -3, -4, -5 or -6) are increased approximately 4 fold 2 h after treatment and then decline. Northern blotting confirms that hepatic IGFBP-1 mRNA abundance also is increased acutely in both IL-1 alpha- and TNF alpha-treated animals. Similar results obtained in adrenalectomized mice indicate that adrenal activation is not required for this effect. Cell culture studies show that cytokines exert direct effects on the production of IGFBP-1 by HepG2 hepatoma cells, increasing IGFBP-1 levels in conditioned medium and the abundance of IGFBP-1 mRNA approximately 3-fold. In contrast, transient transfection studies with IGFBP-1 promoter/luciferase reporter gene constructs show that IGFBP-1 promoter activity is reduced after 18 hr cytokine treatment. We conclude that IL-1 alpha and TNF alpha increase circulating levels of IGFBP-1, reflecting direct effects on hepatic IGFBP-1 mRNA abundance. Stimulation of hepatic IGFBP-1 production may contribute to alterations in IGF bioactivity and impaired anabolism in clinical conditions where cytokine production is high. Additional studies are required to identify specific mechanisms mediating effects of cytokines on hepatic production of IGFBP-1.     

An Unusual Dephosphorylation Reaction

Abstract

In the course of our work to prepare l¹, Z²-seco-nucleotides, an unusual dephosphorylation reaction took place. When compound 1 was subjected to transfer hydrogenation conditions, the expected product was not obtained. Instead, a crystalline solid that proved not to have phosphorus was isolated in 78% yield. ¹H and ¹³C nmr analyses confirmed the hydrogenolysis of the benzyl groups as well as the loss of the phenyl esters. with elemental analytical data suggested that the structure of the compound could be either the 2′,5′-anhydro (2, R[dbnd]H) or 3′,5′-an- hydro derivative 3. precluded the use of spectroscopic analyses to prove the struc-ture. However, based on our experience with related compounds, structure 2 was favored, and we set out to prove it by another synthetic route.     

Meta-QTL analysis of seed iron and zinc concentration and content in common bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.)

Key message

Twelve meta-QTL for seed Fe and Zn concentration and/or content were identified from 87 QTL originating from seven population grown in sixteen field trials. These meta-QTL include 2 specific to iron, 2 specific to zinc and 8 that co-localize for iron and zinc concentrations and/or content.

Abstract

Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification breeding programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrient deficiencies. Biofortification efforts thus far have relied on phenotypic selection of raw seed mineral concentrations in advanced generations. While numerous quantitative trait loci (QTL) studies have been conducted to identify genomic regions associated with increased Fe and Zn concentration in seeds, these results have yet to be employed for marker-assisted breeding. The objective of this study was to conduct a meta-analysis from seven QTL studies in Andean and Middle American intra- and inter-gene pool populations to identify the regions in the genome that control the Fe and Zn levels in seeds. Two meta-QTL specific to Fe and two meta-QTL specific to Zn were identified. Additionally, eight Meta QTL that co-localized for Fe and Zn concentration and/or content were identified across seven chromosomes. The Fe and Zn shared meta-QTL could be useful candidates for marker-assisted breeding to simultaneously increase seed Fe and Zn. The physical positions for 12 individual meta-QTL were identified and within five of the meta-QTL, candidate genes were identified from six gene families that have been associated with transport of iron and zinc in plants.

     

The Influence of Location,Tree Age and Forest Habitat Type on Basic Fuel Properties of the Wood of the Silver Birch (<Emphasis Type="Italic">Betula pendula</Emphasis> Roth.) in Poland

The most extensive study to be carried out in Poland, and one of only a few worldwide, regarding the influence of location, tree age and forest habitat type on the basic fuel properties of silver birch (Betula pendula Roth.) wood was conducted in 12 Forestry Districts of the Polish State Forests. The field study included trees in three age groups of approximately 30, 50 and 70 years. The research was carried out in a fresh broadleaved forest (FBF) habitat type, where in Poland silver birch stands predominate in respect of coverage area and merchantable volume. Additionally, for five selected Forestry Districts, a comparative study was conducted in a fresh mixed broadleaved forest (FMBF), the second most important habitat of this tree species. A total of 306 test trees were examined. For every sample, calorific value and contents of ash, carbon, hydrogen, nitrogen, sulphur and chlorine were determined. The results indicated a statistically significant influence of location on the calorific value (p?=?0.0001) and on the contents of ash (p?<?0.0001), carbon (p?<?0.0001), hydrogen (p?<?0.0001), nitrogen (p?<?0.0001) and chlorine (p?<?0.0001) in the analysed wood. Moreover, statistically significant differences were observed between values of ash content (p?=?0.046) and of calorific value (p?=?0.0026) depending on the forest habitat type. Tree age was found to have no significant influence on the calorific value of silver birch wood.