Opposing Effects of Low Molecular Weight Heparins on the Release of Inflammatory Cytokines from Peripheral Blood Mononuclear Cells of Asthmatics

Background

T-cell-mediated inflammatory cytokines, such as interleukin (IL)-4, IL-5, IL-13 and tumor necrosis factor-alpha (TNF-α), play an important role in the initiation and progression of inflammatory airways diseases. Low-molecular-weight heparins (LMWHs), widely used anticoagulants, possess anti-inflammatory properties making them potential treatment options for inflammatory diseases, including asthma. In the current study, we investigated the modulating effects of two LMWHs (enoxaparin and dalteparin) on the release of cytokines from stimulated peripheral blood mononuclear cells (PBMCs) of asthmatic subjects to identify the specific components responsible for the effects.

Methods

PBMCs from asthmatic subjects (consist of ~75% of T-cells) were isolated from blood taken from ten asthmatic subjects. The PBMCs were pre-treated in the presence or absence of different concentrations of LMWHs, and were then stimulated by phytohaemagglutinin for the release of IL-4, IL-5, IL-13 and TNF-α. LMWHs were completely or selectively desulfated and their anticoagulant effect, as well as the ability to modulate cytokine release, was determined. LMWHs were chromatographically fractionated and each fraction was tested for molecular weight determination along with an assessment of anticoagulant potency and effect on cytokine release.

Results

Enoxaparin inhibited cytokine release by more than 48%, whereas dalteparin increased their release by more than 25%. The observed anti-inflammatory effects of enoxaparin were independent of their anticoagulant activities. Smaller fractions, in particular dp4 (four saccharide units), were responsible for the inhibitory effect of enoxaparin. Whereas, the larger fractions, in particular dp22 (twenty two saccharide units), were associated with the stimulatory effect of dalteparin.

Conclusion

Enoxaparin and dalteparin demonstrated opposing effects on inflammatory markers. These observed effects could be due to the presence of structurally different components in the two LMWHs arising from different methods of depolymerisation. This study provides a platform for further studies investigating the usefulness of enoxaparin in various inflammatory diseases.     

Assessing the Use of Functional Diversity as a Measure of Ecological Resilience in Arid Rangelands

It is becoming more apparent that species richness alone many not be sufficient to fully understand ecosystem resilience but that functional diversity (diversity of species having similar effects on an ecosystem process) may be more relevant. In particular, response diversity (diversity of species that respond differently to disturbance) within functional groups (FG) is suggested to be critical for resilience. We assess for the first time the use of response diversity as a measure of resilience in an empirical study. Our experimental design consisted of sites with three disturbance intensities during a grazing exclosure period and the same sites, 1 year later, after grazing. Plant FGs were identified based on effect traits related to nutrient cycling and soil retention, and species richness within groups was assessed during exclosure and after grazing. To assess if response diversity could predict loss of species richness (resilience analysis), response diversity was calculated only during the exclosure period, based on traits related to grazing tolerance. We also assessed the contribution of richness to response diversity during exclosure (redundancy analysis). Response diversity was significantly and highly correlated with species richness within FGs during disturbance. That is, FGs with the lowest response diversity were the most affected, disappearing when disturbance appeared. Richness within FGs during exclosure was not significantly correlated with response diversity, showing that higher richness does not ensure resilience. We conclude that response diversity can be used to predict which FGs are more resilient, and hence, less vulnerable to future disturbance.     

Mechanisms of Araucaria (Atlantic) Forest Expansion into Southern Brazilian Grasslands

Recent studies have shown that tropical and subtropical forests expanded during the late Holocene, but rates and mechanisms of expansion are still unknown. Here, we investigate how a forest–grassland mosaic changed over the past 10,000 years at the southernmost limit of the Brazilian Atlantic forest. We used soil organic matter carbon isotopes (δ¹³C and ¹⁴C) to quantify and date changes in vegetation, examining soil properties and leaf traits of tree species (nutrient content, δ¹³C, δ¹⁵N, and specific leaf area—SLA) to describe potential mechanisms of expansion. Our results show that after several millennia of stability, forests have been expanding over grasslands through continuous, but very slow, border dynamics and patch formation (<100 m since ~4,000 YBP). This process of expansion coincided with past changes in climate, but biotic feedback mechanisms also appear to be important for the long-term persistence and expansion of forests. Soil fertility and microbial biomass match current rather than past vegetation distribution, increasing progressively across the gradient: grasslands < isolated trees < forest patches < forests. Foliar δ¹⁵N values of trees that are able to colonize the grassland are consistently lower across this vegetation gradient, suggesting an increasingly greater reliance on symbiotic nutrient uptake from grasslands to forests. No significant relationships were found between soil and leaf nutrients, but SLA explained variation in leaf N, P, and K (positive relationships) and in leaf δ¹³C (negative relationship). These findings suggest that a tradeoff between tree growth and water use efficiency is an important regulator of forest–grassland dynamics in the study region.     

Modelling Interactions between Forest Pest Invasions and Human Decisions Regarding Firewood Transport Restrictions

The invasion of nonnative, wood-boring insects such as the Asian longhorned beetle (A. glabripennis) and the emerald ash borer (A. planipennis) is a serious ecological and economic threat to Canadian deciduous and mixed-wood forests. Humans act as a major vector for the spread of these pests via firewood transport, although existing models do not explicitly capture human decision-making regarding firewood transport. In this paper we present a two-patch coupled human-environment system model that includes social influence and long-distance firewood transport and examines potential strategies for mitigating pest spread. We found that increasing concern regarding infestations (f) significantly reduced infestation. Additionally it resulted in multiple thresholds at which the intensity of infestation in a patch was decreased. It was also found that a decrease in the cost of firewood purchased in the area where it is supposed to be burned (C _l) resulted in an increased proportion of local-firewood strategists, and a 67% decrease in C _l from $6.75 to $4.50 was sufficient to eliminate crosspatch infestation. These effects are synergistic: increasing concern through awareness and education campaigns acts together with reduced firewood costs, thereby reducing the required threshold of both awareness and economic incentives. Our results indicate that the best management strategy includes a combination of public education paired with firewood subsidization.     

Woody Species Diversity in Forest Plantations in a Mountainous Region of Beijing,China: Effects of Sampling Scale and Species Selection

The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr.), planted larch (Larix principis-rupprechtii Mayr.), and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer), while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation.     

Amino acid-based enantiomerically pure 3-substituted 1,4-benzodiazepin-2-ones: a new class of anti-ischemic agents

A series of 3-substituted 1,4-benzodiazepin-2-ones derived from S and R amino acids were evaluated for their anti-ischemic activity in vitro. Treatment with compounds 7h, 16, 9d, and 17 decreased the apoptotic neuronal number, however increased the neuronal viability. The compounds decreasing apoptosis could protect neurons from the ischemic injury. The difference in the activities of 1,4-benzodiazepin-2-ones derived from S- and R-amino acids is discussed and explained on the basis of molecular modeling studies.     

Nimbolide sensitizes human colon cancer cells to TRAIL through reactive oxygen species- and ERK-dependent up-regulation of death receptors, p53, and Bax

TNF-related apoptosis-inducing ligand (TRAIL) shows promise as a cancer treatment, but acquired tumor resistance to TRAIL is a roadblock. Here we investigated whether nimbolide, a limonoid, could sensitize human colon cancer cells to TRAIL. As indicated by assays that measure esterase activity, sub-G(1) fractions, mitochondrial activity, and activation of caspases, nimbolide potentiated the effect of TRAIL. This limonoid also enhanced expression of death receptors (DRs) DR5 and DR4 in cancer cells. Gene silencing of the receptors reduced the effect of limonoid on TRAIL-induced apoptosis. Using pharmacological inhibitors, we found that activation of ERK and p38 MAPK was required for DR up-regulation by nimbolide. Gene silencing of ERK abolished the enhancement of TRAIL-induced apoptosis. Moreover, our studies indicate that the limonoid induced reactive oxygen species production, which was required for ERK activation, up-regulation of DRs, and sensitization to TRAIL; these effects were mimicked by H(2)O(2). In addition, nimbolide down-regulated cell survival proteins, including I-FLICE, cIAP-1, cIAP-2, Bcl-2, Bcl-xL, survivin, and X-linked inhibitor of apoptosis protein, and up-regulated the pro-apoptotic proteins p53 and Bax. Interestingly, p53 and Bax up-regulation by nimbolide was required for sensitization to TRAIL but not for DR up-regulation. Overall, our results indicate that nimbolide can sensitize colon cancer cells to TRAIL-induced apoptosis through three distinct mechanisms: reactive oxygen species- and ERK-mediated up-regulation of DR5 and DR4, down-regulation of cell survival proteins, and up-regulation of p53 and Bax.     

KT/HAK/KUP potassium transporters gene family and their whole-life cycle expression profile in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>)

KT/HAK/KUP potassium transporter protein-encoding genes constitute a large family in the plant kingdom. The KT/HAK/KUP family is important for various physiological processes of plant life. In this study, we identified 27 potential KT/HAK/KUP family genes in rice (Oryza sativa) by database searching. Analysis of these KT/HAK/KUP family members identified three conserved motifs with unknown functions, and 11-15 trans-membrane segments, most of which are conserved. A total of 144 putative cis-elements were found in the 2 kb upstream region of these genes, of which a Ca2+-responsive cis-element, two light-responsive cis-elements, and a circadian-regulated cis-element were identified in the majority of the members, suggesting regulation of these genes by these signals. A comprehensive expression analysis of these genes was performed using data from microarrays hybridized with RNA samples of 27 tissues covering the entire life cycle from three rice genotypes, Minghui 63, Zhenshan 97, and Shanyou 63. We identified preferential expression of two OsHAK genes in stamen at 1 day before flowering compared with all the other tissues. OsHAK genes were also found to be differentially upregulated or downregulated in rice seedlings subjected to treatments with three hormones. These results would be very useful for elucidating the roles of these genes in growth, development, and stress response of the rice plant.