The antimicrobial peptide LL-37 induces synthesis and release of cysteinyl leukotrienes from human eosinophils--implications for asthma

BACKGROUND

Eosinophils and their products, including leukotrienes and eosinophil cationic protein (ECP), are well-known mediators of inflammation and tissue damage in asthma. The antimicrobial peptide LL-37 exhibits a variety of immunomodulatory activities. However, the role of LL-37 in asthma has not been fully addressed. Here, we aim to investigate the effect of LL-37 on inducing inflammatory mediators in human eosinophils, probe the underlying mechanisms, and search for a clinical correlate.

METHODS

Primary eosinophils were isolated from peripheral blood. Leukotriene and ECP levels were measured using EIAs or ELISAs. Activation of leukotriene-synthesizing enzymes and signaling kinases was analyzed by Western blot or immunofluorescent imaging. LL-37/its proform hCAP18 expression was analyzed by Western blot.

RESULTS

LL-37, via formyl peptide receptor-2 (FPR-2), triggered the release of cysteinyl leukotrienes (cys-LTs) from eosinophils. The release was more prominent in cells primed with the eosinophilopoietic cytokine GM-CSF or IL-5 or cells from asthmatic patients. LL-37 stimulates lipid body formation and activates cys-LT-synthesizing enzymes by multiple mechanisms: enhancing cPLA(2) activity by pERK1/2-mediated phosphorylation and inducing intracellular translocation and assembly of 5-LO and LTC(4) S at perinuclear locations and lipid bodies. In addition to cys-LTs, LL-37 enhances ECP release from eosinophils via pERK1/2. The expression of hCAP18 and its release following leukotriene stimulation are significantly higher in eosinophils from asthmatics.

CONCLUSIONS

This study identifies LL-37 as an eosinophil-activating peptide that triggers release of inflammatory mediators. The clinical correlation suggests that LL-37/hCAP18 and its signaling pathway represent potential therapeutic targets for this disease.

Effect of β-(3,4-dihydroxyphenyl)lactic acid on oxidative stress stimulated by high glucose levels in human peritoneal mesothelial cells

OBJECTIVE

To investigate the effects of β-(3,4-dihydroxyphenyl)lactic acid on oxidative stress stimulated by high glucose levels in human peritoneal mesothelial cells (HPMCs) in vitro.

METHODS

HPMCs were incubated with 100 mol/l glucose followed by 0.625-20 mg/ml β-(3,4-dihydroxyphenyl)lactic acid. Reactive oxygen species (ROS) were quantified by flow cytometry. Relative levels of fibronectin-1 (FN1), collagen-I α(1) (COL1A1), endothelin-1 (EDN1) and haem oxygenase-1 (HMOX1) mRNA and protein were quantified by real-time reverse transcription-polymerase chain reaction and Western blotting, respectively. Absolute levels of FN1 and COLIA1 were quantified by enzyme-linked immunosorbent assay.

RESULTS

β-(3,4-Dihydroxyphenyl)lactic acid significantly decreased ROS levels, and EDN1 mRNA and protein levels, in dose- and time-dependent manners. HMOX1 mRNA and protein levels were significantly increased by β-(3,4-dihydroxyphenyl)lactic acid in dose-dependent manners. COL1A1 and FN1 mRNA and protein levels were significantly decreased by β-(3,4-dihydroxyphenyl)lactic acid in dose- and time-dependent manners.

CONCLUSIONS

β-(3,4-Dihydroxyphenyl)lactic acid inhibited oxidative stress and reversed increases in FN1 and COLIA1 induced by high glucose levels in HPMCs. This may contribute to a protective role in peritoneal fibrosis.

Crystallization-aided extraordinary plastic deformation in nanolayered crystalline Cu/amorphous Cu-Zr micropillars

Metallic glasses are lucrative engineering materials owing to their superior mechanical properties such as high strength and great elastic strain. However, the Achilles' heel of metallic amorphous materials - low plasticity caused by instantaneous catastrophic shear banding, significantly undercut their structural applications. Here, the nanolayered crystalline Cu/amorphous Cu-Zr micropillars with equal layer thickness spanning from 20-100 nm are uniaxially compressed and it is found that the Cu/Cu-Zr micropillars exhibit superhigh homogeneous deformation (≥ 30% strain) rather than localized shear banding at room temperature. This extraordinary plasticity is aided by the deformation-induced devitrification via absorption/annihilation of abundant dislocations, triggering the cooperative shearing of shear transformation zones in glassy layers, which simultaneously renders the work-softening. The synthesis of such heterogeneous nanolayered structure not only hampers shear band generation but also provides a viable route to enhance the controllability of plastic deformation in metallic glassy composites via deformation-induced devitrification mechanism.

Superconductivity with extremely large upper critical fields in Nb2Pd0.81S5

Here, we report the discovery of superconductivity in a new transition metal-chalcogenide compound, i.e. Nb2Pd0.81S5, with a transition temperature Tc is approximately equal to 6.6 K. Despite its relatively low Tc, it displays remarkably high and anisotropic superconducting upper critical fields, e.g. μ0Hc2 (T → 0 K) > 37 T for fields applied along the crystallographic b-axis. For a field applied perpendicularly to the b-axis, μ0Hc2 shows a linear dependence in temperature which coupled to a temperature-dependent anisotropy of the upper critical fields, suggests that Nb2Pd0.81S5 is a multi-band superconductor. This is consistent with band structure calculations which reveal nearly cylindrical and quasi-one-dimensional Fermi surface sheets having hole and electron character, respectively. The static spin susceptibility as calculated through the random phase approximation, reveals strong peaks suggesting proximity to a magnetic state and therefore the possibility of unconventional superconductivity.

Characteristics of fertile somatic hybrids of G. hirsutum L. and G. trilobum generated via protoplast fusion

Fertile somatic hybrids between tetraploid upland cotton G. hirsutum L. cv. Coker 312 and wild cotton G. trilobum were generated by symmetric electrofusion. Comparisons of morphology, combined with flow cytometric, RAPD, SRAP and AFLP analyses confirmed the hybrid nature of the regenerated plants. The hybrids differed morphologically from the parent plants. Flow cytometric analysis showed that the hybrids had DNA similar in amount to the total combined DNA content of the two parents, and the use of molecular markers revealed that the hybrids contained genomic fragments from both fusion parents, further indicating the hybrid nature of the regenerated plants. The stability of the morphological features of the hybrids was examined in following generations. The hexaploid fusion plants showed strong photosynthesis and a high expression level of some photosystem-related genes. Our results suggest that novel traits may be incorporated in cotton breeding programs through the production of somatic hybrids and the backcrossing of these plants with elite cultivars.

Evolution of π(0) suppression in Au+Au collisions from √(s(NN))=39 to 200 GeV

Neutral-pion π(0) spectra were measured at midrapidity (|y|<0.35) in Au+Au collisions at √(s(NN))=39 and 62.4 GeV and compared with earlier measurements at 200 GeV in a transverse-momentum range of 1<p(T)<10 GeV/c. The high-p(T) tail is well described by a power law in all cases, and the powers decrease significantly with decreasing center-of-mass energy. The change of powers is very similar to that observed in the corresponding spectra for p+p collisions. The nuclear modification factors (R(AA)) show significant suppression, with a distinct energy, centrality, and p(T) dependence. Above p(T)=7 GeV/c, R(AA) is similar for √(s(NN))=62.4 and 200 GeV at all centralities. Perturbative-quantum-chromodynamics calculations that describe R(AA) well at 200 GeV fail to describe the 39 GeV data, raising the possibility that, for the same p(T) region, the relative importance of initial-state effects and soft processes increases at lower energies. The p(T) range where π(0) spectra in central Au+Au collisions have the same power as in p+p collisions is ≈5 and 7 GeV/c for √(s(NN))=200 and 62.4 GeV, respectively. For the √(s(NN))=39 GeV data, it is not clear whether such a region is reached, and the x(T) dependence of the x(T)-scaling power-law exponent is very different from that observed in the √(s(NN))=62 and 200 GeV data, providing further evidence that initial-state effects and soft processes mask the in-medium suppression of hard-scattered partons to higher p(T) as the collision energy decreases.

Thalidomide and chemotherapy combination

Angiogenesis has been shown to be important in tumor growth and metastasis. Thalidomide, an oral sedative, has recently been found to inhibit angiogenesis. We therefore set out to ask whether thalidomide can be used as therapy for breast cancer. In a mouse model of breast cancer, we found that thalidomide alone did not suppress tumor growth. However, mice treated with thalidomide in combination with cytoxan and adriamycin had significantly smaller tumors than those given the two chemotherapeutic agents alone (3,432 +/- 303 mm(3) versus 4,643 +/- 203 mm(3), p = 0.0005). We proceeded to administer thalidomide together with chemotherapy to seven breast cancer patients in the context of a Phase I trial. Side effects attributed to thalidomide were minimal, and included constipation and a rash. We concluded that an approach at cancer therapeutics combining an antiangiogenic agent such as thalidomide with conventional chemotherapy may be feasible and deserves further studies.