Laminar shear stress promotes endothelial cell migration and inhibits cell apoptosis in the presence of hydroxyurea

Cell migration plays important roles in both physiological and pathological processes. Recent studies have shown that hydroxyurea, which is an anti-proliferative inhibitor, can affect cell morphology and specific gene expression of endothelial cells (ECs). In vivo, the functions of ECs are modulated by shear stress. It is well known that shear stress can have effects on EC migration by affecting cell morphology, cytoskeletal arrangement and cell-cell junction, and activating mechanosensors, inducing the changes of signaling pathways, and then increasing or decreasing the expression of gene and protein. However, the influences of hydroxyurea on EC function under shear stress are still unclear. In present study, we investigated the effects of hydroxyurea on EC proliferation, apoptosis and migration under laminar shear stress. The results showed that hydroxyurea prevented growth of ECs in a dose-dependent manner. Hydroxyurea at 2 mM completely inhibited the proliferation of ECs. The results also demonstrated that hydroxyurea induced EC apoptosis, but it was inhibited by 15.27 dyn/cm2 laminar shear stress. Furthermore, shear stress induced cell migration in the presence of hydroxyurea. Therefore, 2 mM hydroxyurea, which completely inhibited the proliferation of HUVECs, could be used to eliminate any confounding effect of shear stress on proliferation in shear stress-induced cell migration. These results also do confirm that shear stress plays important roles in achieving and maintaining the stabilization of ECs.

An integrated mathematical model of thrombin-, histamine-and VEGF-mediated signalling in endothelial permeability

BACKGROUND

Endothelial permeability is involved in injury, inflammation, diabetes and cancer. It is partly regulated by the thrombin-, histamine-, and VEGF-mediated myosin-light-chain (MLC) activation pathways. While these pathways have been investigated, questions such as temporal effects and the dynamics of multi-mediator regulation remain to be fully studied. Mathematical modeling of these pathways facilitates such studies. Based on the published ordinary differential equation models of the pathway components, we developed an integrated model of thrombin-, histamine-, and VEGF-mediated MLC activation pathways.

RESULTS

Our model was validated against experimental data for calcium release and thrombin-, histamine-, and VEGF-mediated MLC activation. The simulated effects of PAR-1, Rho GTPase, ROCK, VEGF and VEGFR2 over-expression on MLC activation, and the collective modulation by thrombin and histamine are consistent with experimental findings. Our model was used to predict enhanced MLC activation by CPI-17 over-expression and by synergistic action of thrombin and VEGF at low mediator levels. These may have impact in endothelial permeability and metastasis in cancer patients with blood coagulation.

CONCLUSION

Our model was validated against a number of experimental findings and the observed synergistic effects of low concentrations of thrombin and histamine in mediating the activation of MLC. It can be used to predict the effects of altered pathway components, collective actions of multiple mediators and the potential impact to various diseases. Similar to the published models of other pathways, our model can potentially be used to identify important disease genes through sensitivity analysis of signalling components.

Optical response of a disordered bicontinuous macroporous structure in the longhorn beetle Sphingnotus mirabilis

We studied the structural and optical properties of scales in the longhorn beetle Sphingnotus mirabilis. Structural characterizations revealed that the scale interior possesses a disordered bicontinuous macroporous structure, resembling a phase-separated structure obtained by spinodal decomposition. Its optical response was investigated both experimentally and theoretically. Our results show that this structure has interesting optical properties due to the existence of only short-range order and the lack of well-defined local structures.

Health risk assessment of organochlorine contaminants in fish from a major lake (Baiyangdian Lake) in North China

Organochlorine contaminants (OCs) in fish were determined to evaluate the potential risk to humans consuming fish originating in Baiyangdian Lake, North China. Relatively low levels of PCBs, HCHs and DDTs were observed, with mean concentrations ranging from 0.28 to 3.28 ng/g, wet weight. Among various fish species tested, the highest burden of OCs was recorded in northern snakehead (7.39 ng/g, wet weight) and the lowest was in grass carp (2.04 ng/g, wet weight). The hazard ratios (HRs), based on noncancer risk were all less than 1.0, while the HRs based on cancer risk exceeded 1.0 only for PCBs based on the 90th percentile concentration.

Hydrogen sulfide attenuated tumor necrosis factor-α-induced inflammatory signaling and dysfunction in vascular endothelial cells

Background

Hydrogen sulfide (H₂S), the third physiologically relevant gaseous molecule, is recognized increasingly as an anti-inflammatory mediator in various inflammatory conditions. Herein, we explored the effects and mechanisms of sodium hydrosulfide (NaHS, a H₂S donor) on tumor necrosis factor (TNF)-α-induced human umbilical vein endothelial cells (HUVEC) dysfunction.

Methodology and Principal Findings

Application of NaHS concentration-dependently suppressed TNF-α-induced mRNA and proteins expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), mRNA expression of P-selectin and E-selectin as well as U937 monocytes adhesion to HUVEC. Western blot analysis revealed that the expression of the cytoprotective enzyme, heme oxygenase-1 (HO-1), was induced and coincident with the anti-inflammatory action of NaHS. Furthermore, TNF-α-induced NF-κB activation assessed by IκBα degradation and p65 phosphorylation and nuclear translocation and ROS production were diminished in cells subjected to treatment with NaHS.

Significance

H₂S can exert an anti-inflammatory effect in endothelial cells through a mechanism that involves the up-regulation of HO-1.

Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/ψ→γπ+π-η'

With a sample of (225.2±2.8)×10(6) J/ψ events registered in the BESIII detector, J/ψ→γπ(+)π(-)η(') is studied using two η(') decay modes: η(')→π(+)π(-)η and η(')→γρ(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the π(+)π(-)η(') invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.4σ, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.

2-[4-(4,5-Dihydro-1H-imidazol-2-yl)phenyl]-4,5-dihydro-1H-imidazol-3-ium 4-aminobenzoate

In the cation of the title compound, C₁₂H₁₅N₄⁺·C₇H₆NO₂⁻, the benzene ring makes dihedral angles of 30.51 (9) and 25.64 (9)° with the imidazole and imidazolinium rings, respectively. In the crystal, inter­molecular N—H⋯O and N—H⋯N hydrogen-bonding inter­actions link the mol­ecules into a three-dimensional network.

S-propargyl-cysteine, a novel hydrogen sulfide-modulated agent, attenuates lipopolysaccharide-induced spatial learning and memory impairment: involvement of TNF signaling and NF-κB pathway in rats

Neuroinflammation exacerbates hyperphosphorylated tau and amyloid-β (Aβ) generation by generating a plethora of inflammatory mediators and neurotoxic compounds in a transgenic model of Alzheimer's disease (AD), and it was reported that hydrogen sulfide (H₂S) attenuates lipopolysaccharide (LPS)-induced neuroinflammation both in vitro and in vivo. In the present study, the protective effects of S-propargyl-cysteine (SPRC) on spatial learning and memory impairment induced by LPS were examined in vivo, and the possible mechanisms were explored. The data showed that SPRC administration by intraperitoneal (i.p.) injection may attenuate cognitive impairment induced by bilateral intracerebroventricular (b.i.c.v.) injection of 5 μg of LPS in rats. Subsequently, SPRC prevented a decrease of H₂S levels in rat hippocampus subjected to LPS. Furthermore, SPRC afforded beneficial actions in inhibitions tumor necrosis factor (TNF)-α, TNF-α receptor 1 (TNFR1) and Aβ generation, as well as IκB-α degradation and phospho-transcription factors of the nuclear factor κB p65 (p-NF-κB p65) activation induced by LPS. These findings suggested that SPRC, a novel H₂S-modulated agent, might be a potential agent for the treatment of neuroinflammation-related diseases, such as AD.

Evidence for ψ' decays into γπ0 and γη

The decays ψ'→γπ(0), γη and γη' are studied using data collected with the BESIII detector at the BEPCII e(+)e(-) collider. The processes ψ'→γπ(0) and ψ'→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ'→γπ(0))=(1.58±0.40±0.13)×10(-6), B(ψ'→γη)=(1.38±0.48±0.09)×10(-6), and B(ψ'→γη')=(126±3±8)×10(-6), where the first errors are statistical and the second ones systematic.

Leonurine improves ischemia-induced myocardial injury through antioxidative activity

The present study was designed to investigate the protective effects of 4-guanidino-n-butyl syringate (leonurine), a compound in Herba Leonuri (HL) on ischemic rat heart to determine the protective mechanisms associated with ischemic rat hearts. Rat heart ischemia was induced by ligation of the left coronary artery. Creatine kinase (CK) and lactate dehydrogenase (LDH) in plasma and superoxide dismutase (SOD) activity in heart homogenates were measured. We found leonurine significantly decreased levels of LDH and CK activities in plasma. This observation corresponded with decreased infarct size of ischemic rat heart induced by ligation of the left coronary artery. Moreover, the mRNA expression of the pro-apoptotic gene Bax was significantly down-regulated by 0.68-fold (p < 0.05) and the anti-apoptotic gene Bcl-2 was up-regulated by 1.41-fold (p < 0.05) in the leonurine treated groups as compared with acute myocardium ischemia (MI) controls measured by RT-PCR. Correspondingly, Bcl-2 and Bax protein levels detected by Western blotting coincided with gene expression levels. In addition, the mRNA expression level of the antioxidant enzyme Mn-SOD was significantly increased 1.23-fold (p < 0.05) and this finding corresponded with an observed increase in SOD activity and also with a committed decrease in lipid peroxidation. Taken together, our results demonstrated that leonurine attenuated myocardium injury during MI via antioxidative and anti-apoptotic effects and leonurine might become a useful adjuvant cardioprotective agent.

Structural coloration and photonic pseudogap in natural random close-packing photonic structures

Scales on the elytra of longhorn beetle Anoplophora graafi display diverse non-iridescent colors ranging from blue, green, yellow, and red to purple. By structural characterizations, optical measurements, and theoretical calculations, we found that the scale colors stem from an amorphous photonic structure possessing only short-range order: random close-packing of chitin nanoparticles. Our results showed that direction-independent photonic pseudogaps found in the photon density of states of the random close-packing photonic structure are the ultimate physical origin for non-iridescent coloration of scales. The color steering strategy of scales is ingenious, simply by varying the size of chitin nanoparticles. Revealed natural random close-packing photonic structures and the color steering strategy of scales could render valuable inspiration for the artificial fabrication and design of photonic structures and devices as well.

3,3'-(p-Phenyl-enedimethyl-ene)di-1H-imidazol-1-ium bis-(4-nitro-benzoate)-4-nitro-benzoic acid (1/2)

The asymmetric unit of the title compound, C₁₄H₁₆N₄²⁺·2C₇H₄NO₄⁻·2C₇H₅NO₄, comprises one-half of the 3,3′-(p-phenyl­enedimethyl­ene)di-1H-imidazol-1-ium dication, which lies on an inversion centre, one 4-nitro­benzoate anion and one 4-nitro­benzoic acid mol­ecule. In the crystal, the components are linked into a two-dimensional network parallel to (110) by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds.

Identifying Novel Type ZBGs and Nonhydroxamate HDAC Inhibitors Through a SVM Based Virtual Screening Approach

Histone deacetylase inhibitors (HDACi) have been successfully used for the treatment of cancers and other diseases. Search for novel type ZBGs and development of non-hydroxamate HDACi has become a focus in current research. To complement this, it is desirable to explore a virtual screening (VS) tool capable of identifying different types of potential inhibitors from large compound libraries with high yields and low false-hit rates similar to HTS. This work explored the use of support vector machines (SVM) combined with our newly developed putative non-inhibitor generation method as such a tool. SVM trained by 702 pre-2008 hydroxamate HDACi and 64334 putative non-HDACi showed good yields and low false-hit rates in cross-validation test and independent test using 220 diverse types of HDACi reported since 2008. The SVM hit rates in scanning 13.56 M PubChem and 168K MDDR compounds are comparable to HTS rates. Further structural analysis of SVM virtual hits suggests its potential for identification of non-hydroxamate HDACi. From this analysis, a series of novel ZBG and cap groups were proposed for HDACi design.

Abstract LB-375: Development of new compounds specifically targeting prostate cancer bone metastases

Introduction: Bone metastases are a major cause of morbidity for men with prostate cancer (PCa). Although PCa cells produce osteoblastic metastases, there is an initial and ongoing osteoclast (OC)-mediated osteolytic phase that is essential for PCa bone metastases. OC-mediated bone resorption is dependent upon OC secretion of bone acid phosphatase. PCa cells in bone secrete high levels of prostatic acid phosphatase (PAP) which differs from BAP in that PAP enzymatic activity is inhibited by tartrate and glyceric acid, whereas BAP is tartrate-resistant.

Hypothesis: PAP secreted by human PCa cells in bone acts similarly to OC-derived bone acid phosphatase to degrade bone matrix and enhance PCa bone-targeting and growth in bone. We developed new compounds consisting of glyceric acid or tartrate (known PAP inhibitors) conjugated to a bisphosphonate to inhibit PCa bone metastases.

Methods: PCa bone metastases derived from 7 patients were immunostained for androgen receptor (AR), prostate specific antigen (PSA) and PAP expression. The VCaP human PCa cell line derived from a vertebral metastases was inoculated intratibially into SCID mice (n=8) and bone lesions immunostained for AR, PSA, and PAP. Co-cultures of MC3T3 osteoblasts and VCaP cells were treated with tartrate and the effects on cell number, PAP and bone alkaline phosphatase (ALP) secretion measured by ELISA. Glyceric Acid and Tartaric acid were then conjugated with alendronate and the effects of these new conjugates on PAP enzymatic activity were compared to alendronate alone and tartrate alone.

Results: Human PCa bone lesions (7/7) had strongly positive expression of PAP, with little AR or PSA expression. 8/8 SCID mice inoculated with VCaP cells intratibially developed osteoblastic VCaP lesions and these similarly had high PAP expression and no PSA expression. Tartrate addition to co-cultures of VCaP and MC3T3 osteoblasts reduced MC3T3 cell numbers and ALP secretion. In vitro testing of the conjugates revealed that the glyceric acid-alendronate conjugate inhibited PAP enzymatic activity but the tartrate-alendronate conjugate and alendronate alone had no significant inhibitory activity.

Discussion: We have evidence that PAP secretion by PCa cells enhances their bone metastatic ability. We have developed new bone-targeting agents that consist of alendronate conjugated to PAP-inhibitory small molecules for further development as oral agents to prevent and treat PCa bone metastases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-375.