Toll-like receptor 4 contributes to vascular remodelling and endothelial dysfunction in angiotensin II-induced hypertension

BACKGROUND AND PURPOSE

Toll-like receptor 4 (TLR4) signalling contributes to inflammatory cardiovascular diseases, but its role in hypertension and the associated vascular damage is not known. We investigated whether TLR4 activation contributed to angiotensin II (AngII)-induced hypertension and the associated vascular structural, mechanical and functional alterations.

EXPERIMENTAL APPROACH

AngII was infused (1.44 mg · kg(-1) · day(-1), s.c.) for 2 weeks in C57BL6 mice, treated with a neutralizing anti-TLR4 antibody or IgG (1 μg · day(-1); systolic BP (SBP) and aortic cytokine levels were measured. Structural, mechanical and contractile properties of aortic and mesenteric arterial segments were measured with myography and histology. RT-PCR and Western blotting were used to analyse these tissues and cultured vascular smooth muscle cells (VSMC) from hypertensive rats (SHR).

KEY RESULTS

Aortic TLR4 mRNA levels were raised by AngII infusion. Anti-TLR4 antibody treatment of AngII-treated mice normalised: (i) increased SBP and TNF-α, IL-6 and CCL2 levels; (ii) vascular structural and mechanical changes; (iii) altered aortic phenylephrine- and ACh-induced responses; (iv) increased NOX-1 mRNA levels, superoxide anion production and NAD(P)H oxidase activity and effects of catalase, apocynin, ML-171 and Mito-TEMPO on vascular responses; and (v) reduced NO release and effects of L-NAME on phenylephrine-induced contraction. In VSMC, the MyD88 inhibitor ST-2825 reduced AngII-induced NAD(P)H oxidase activity. The TLR4 inhibitor CLI-095 reduced AngII-induced increased phospho-JNK1/2 and p65 NF-κB subunit nuclear protein expression.

CONCLUSIONS AND IMPLICATIONS

TLR4 up-regulation by AngII contributed to the inflammation, endothelial dysfunction, vascular remodelling and stiffness associated with hypertension by mechanisms involving oxidative stress. MyD88-dependent activation and JNK/NF-κB signalling pathways participated in these alterations.

Role of COX-2-derived PGE2 on vascular stiffness and function in hypertension

BACKGROUND AND PURPOSE

Prostanoids derived from COX-2 and EP receptors are involved in vascular remodelling in different cardiovascular pathologies. This study evaluates the contribution of COX-2 and EP1 receptors to vascular remodelling and function in hypertension.

EXPERIMENTAL APPROACH

Spontaneously hypertensive rats (SHR) and angiotensin II (AngII)-infused (1.44 mg · kg(-1) · day(-1), 2 weeks) mice were treated with the COX-2 inhibitor celecoxib (25 mg · kg(-1) · day(-1) i.p) or with the EP1 receptor antagonist SC19220 (10 mg · kg(-1) · day(-1) i.p.). COX-2(-/-) mice with or without AngII infusion were also used.

KEY RESULTS

Celecoxib and SC19220 treatment did not modify the altered lumen diameter and wall : lumen ratio in mesenteric resistance arteries from SHR-infused and/or AngII-infused animals. However, both treatments and COX-2 deficiency decreased the augmented vascular stiffness in vessels from hypertensive animals. This was accompanied by diminished vascular collagen deposition, normalization of altered elastin structure and decreased connective tissue growth factor and plasminogen activator inhibitor-1 gene expression. COX-2 deficiency and SC19220 treatment diminished the increased vasoconstrictor responses and endothelial dysfunction induced by AngII infusion. Hypertensive animals showed increased mPGES-1 expression and PGE2 production in vascular tissue, normalized by celecoxib. Celecoxib treatment also decreased AngII-induced macrophage infiltration and TNF-α expression. Macrophage conditioned media (MCM) increased COX-2 and collagen type I expression in vascular smooth muscle cells; the latter was reduced by celecoxib treatment.

CONCLUSIONS AND IMPLICATIONS

COX-2 and EP1 receptors participate in the increased extracellular matrix deposition and vascular stiffness, the impaired vascular function and inflammation in hypertension. Targeting PGE2 receptors might have benefits in hypertension-associated vascular damage.

Melting-point depression by insoluble impurities: a finite size effect

Melting-point depression by soluble impurities is an entropy-driven phenomenon. Studying partially oxidized free sodium nanoparticles, we found an additional mechanism, which is caused by insoluble impurities. Oxidization of sodium clusters with 135-192 atoms by a single oxygen molecule causes a melting-point depression of 17+/-6 K; additional oxygen amplifies the effect. This is in contrast to the behavior of bulk sodium, where the melting point does not change upon partial oxidization. First-principles density functional theory calculations reveal the interaction between the pure and the oxidized part of the cluster to be responsible for the effect. There is more structural freedom in a liquid cluster to optimize the interface between the two parts. This stabilizes the liquid phase and causes the observed, cluster-specific melting-point depression.

HuR mediates the synergistic effects of angiotensin II and IL-1β on vascular COX-2 expression and cell migration

BACKGROUND AND PURPOSE

Angiotensin II (AngII) and IL-1β are involved in cardiovascular diseases through the induction of inflammatory pathways. HuR is an adenylate- and uridylate-rich element (ARE)-binding protein involved in the mRNA stabilization of many genes. This study investigated the contribution of HuR to the increased expression of COX-2 induced by AngII and IL-1β and its consequences on VSMC migration and remodelling.

EXPERIMENTAL APPROACH

Rat and human VSMCs were stimulated with AngII (0.1 μM) and/or IL-1β (10 ng · mL(-1)). Mice were infused with AngII or subjected to carotid artery ligation. mRNA and protein levels were assayed by quantitative PCR, Western blot, immunohistochemistry and immunofluorescence. Cell migration was measured by wound healing and transwell assays.

KEY RESULTS

In VSMCs, AngII potentiated COX-2 and tenascin-C expressions and cell migration induced by IL-1β. This effect of AngII on IL-1β-induced COX-2 expression was accompanied by increased COX-2 3' untranslated region reporter activity and mRNA stability, mediated through cytoplasmic HuR translocation and COX-2 mRNA binding. These effects were blocked by ERK1/2 and HuR inhibitors. VSMC migration was reduced by blockade of ERK1/2, HuR, COX-2, TXAS, TP and EP receptors. HuR, COX-2, mPGES-1 and TXAS expressions were increased in AngII-infused mouse aortas and in carotid-ligated arteries. AngII-induced tenascin-C expression and vascular remodelling were abolished by celecoxib and by mPGES-1 deletion.

CONCLUSIONS AND IMPLICATIONS

The synergistic induction of COX-2 by AngII and IL-1β in VSMCs involves HuR through an ERK1/2-dependent mechanism. The HuR/COX-2 axis participates in cell migration and vascular damage. HuR might be a novel target to modulate vascular remodelling.

Is the gas-phase OH+H2CO reaction a source of HCO in interstellar cold dark clouds? A kinetic, dynamic and modelling study

Chemical kinetics of neutral-neutral gas-phase reactions at ultralow temperatures is a fascinating research subject with important implications on the chemistry of complex organic molecules in the interstellar medium (T∼10-100K). Scarce kinetic information is currently available for this kind of reactions at T<200 K. In this work we use the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means Reaction Kinetics in a Uniform Supersonic Flow) technique to measure for the first time the rate coefficients (k) of the gas-phase OH+H2CO reaction between 22 and 107 K. k values greatly increase from 2.1×10-11 cm3 s-1 at 107 K to 1.2×10-10 cm3 s-1 at 22 K. This is also confirmed by quasi-classical trajectories (QCT) at collision energies down to 0.1 meV performed using a new full dimension and ab initio potential energy surface, recently developed which generates highly accurate potential and includes long range dipole-dipole interactions. QCT calculations indicate that at low temperatures HCO is the exclusive product for the OH+H2CO reaction. In order to revisit the chemistry of HCO in cold dense clouds, k is reasonably extrapolated from the experimental results at 10K (2.6×10-10 cm3 s-1). The modeled abundances of HCO are in agreement with the observations in cold dark clouds for an evolving time of 105-106 yrs. The different sources of production of HCO are presented and the uncertainties in the chemical networks discussed. This reaction can be expected to be a competitive process in the chemistry of prestellar cores. The present reaction is shown to account for a few percent of the total HCO production rate. Extensions to photodissociation regions and diffuse clouds environments are also commented.

Towards the Improvement of Fruit-Quality Parameters in Citrus under Deficit Irrigation Strategies

Water shortage is becoming a severe problem in arid and semiarid regions worldwide, reducing the availability of agricultural land and water resources. In Spain, citrus is one of the most economically important crops, with 74,000 ha devoted to its cultivation. Since water resources are increasingly more insufficient, the efficient use of water is becoming more essential. Deficit irrigation in many agricultural crops has frequently proved to be an efficient tool for improving water-use efficiency. This paper examines the effects a deficit irrigation during the ripening period on yield and the most representative fruit quality properties. The study was conducted during two consecutive years (2009-2010) in a commercial 12-year-old orange orchard (Citrus sinensis L. Osb. cv. Navelina) grafted onto Carrizo citrange (Citrus sinensis L. Osb. × Poncirus Trifoliata L. Osb.). A regulated deficit irrigation (DI) was applied, which was fully irrigated during the flowering and fruit-growth stage, and during the ripening period it was subjected to a water-stress ratio of 0.75. A control treatment was established, this being irrigated at 100% of crop evapotranspiration. Along the water stress period, it was tested the temporal evolution of the main organoleptic and nutraceutical fruit properties (color index, the total soluble solids, titrable acidity, maturity index, rind weight, juice weight, the ratio of juice weight versus fruit weight, and the total C vitamin and flavonoids). It was not observed a descend in juice content, or fruit weight, or in the final yield. In terms of fruit organoleptic and nutraceutical properties, there were not detected negative effects in the studied properties. Furthermore, DI treatment showed higher values of maturity index than control treatment, which can be considered as a positive aspect in the fruit quality. Considering these results, we can affirm that a moderate water stress applied during the maturity period is a sustainable strategy for saving water, increasing the irrigation productivity and obtaining fruits with similar properties to those without deficit irrigation.

Isolation and characterization of human gingival microvascular endothelial cells

BACKGROUND AND OBJECTIVE

Endothelial cells have a substantial role in maintaining vascular homeostasis, and their dysregulation can contribute to the development of pathology. The plasminogen activators and their inhibitors may, arguably, be the single most important proteolytic system of the endothelium for vascular maintenance by controlling plasminogen activation and other proteolytic cascades that impact on clotting, hemodynamics, angiogenesis and the character of the vascular wall. In chronic periodontal disease, significant changes to the microvasculature occur in association with the severity of the disease. Investigation of the role played by endothelial cells in periodontal health and disease has been limited to in situ immunolocalization or to the use of endothelial cells of nongingival origin, such as human umbilical vein endothelial cells. The objective of this research was to establish a replicable protocol for isolating microvascular endothelial cells from the gingiva.

MATERIAL AND METHODS

From inflamed gingiva, isolated cells were characterized by morphology, the expression of factor VIII-related antigen, the expression of UEA-1 ligand, the uptake of acetylated low-density lipoprotein, network formation on Matrigel, and by the expression levels of urokinase plasminogen activator, tissue plasminogen activator, plasminogen activator inhibitor-1 and collagen IV.

RESULTS AND CONCLUSION

Gingival endothelial cells were most readily obtained from inflamed gingival tissues, and these endothelial cells, when isolated by the protocol established herein, demonstrated endothelial characteristics and constitutively secreted plasminogen activators and plasminogen activator inhibitor-1 in culture.

Trans-cis molecular photoswitching in interstellar Space

As many organic molecules, formic acid (HCOOH) has two conformers (trans and cis). The energy barrier to internal conversion from trans to cis is much higher than the thermal energy available in molecular clouds. Thus, only the most stable conformer (trans) is expected to exist in detectable amounts. We report the first interstellar detection of cis-HCOOH. Its presence in ultraviolet (UV) irradiated gas exclusively (the Orion Bar photodissociation region), with a low trans-to-cis abundance ratio of 2.8 ± 1.0, supports a photoswitching mechanism: a given conformer absorbs a stellar photon that radiatively excites the molecule to electronic states above the interconversion barrier. Subsequent fluorescent decay leaves the molecule in a different conformer form. This mechanism, which we specifically study with ab initio quantum calculations, was not considered in Space before but likely induces structural changes of a variety of interstellar molecules submitted to UV radiation.

First Report of Fusarium Wilt Caused by Fusarium oxysporum on Strawberry in Spain

In the spring of 2007, wilted and dead strawberry plants (Fragaria × ananassa Duch. cvs. Camarosa and Ventana) were observed in a soilless culture system in Huelva, southwestern Spain. Approximately 8% of the plants in the field died. Isolations from necrotic crowns and roots and necrotic flowers were made on potato dextrose agar after disinfestation in 0.6% NaOCl for 30 s. Colonies with light purple mycelia and beige or orange reverse colony colors developed after 9 days of incubation at 25°C. Colonies produced abundant microconidia, macroconidia, and chlamydospores. Microconidia were hyaline and oval-ellipsoid to cylindrical (5.9 to 9.2 × 2.1 to 3.4 μm). Macroconidia were 3 to 5 septate and fusoid-subulate with a pedicellate base (28.8 to 37.3 × 3.2 to 4.3 μm). Morphology and growth matched descriptions of Fusarium oxysporum Schlechtend emend. Snyder & Hansen (2). A PCR assay for amplification of r-DNA using primers PFO₂ and PFO₃ established the identity of the isolate as F. oxysporum (1). To confirm the pathogenicity of the fungus, roots of 30-day-old strawberry cvs. Camarosa and Ventana (20 plants each) were inoculated by dipping the roots into a conidial suspension (10⁷ conidia per ml) for 15 min. The inoculated plants were transplanted into plastic pots containing sterilized peat and maintained at 25°C and 100% relative humidity in a growth chamber with a daily 12-h photoperiod of fluorescent light. The pathogenicity test was conducted twice. Within 30 days, all inoculated plants developed wilt symptoms similar to that observed in the field and eventually 75% of the plants died. No symptoms were observed on plants dipped in distilled water. The fungus was successfully reisolated from crowns, roots, and necrotic flowers, fulfilling Koch's postulates. To our knowledge, this is the first report of the occurrence of Fusarium wilt caused by F. oxysporum on strawberry plants in Spain. References: (1) V. Edel et al. Mycol. Res. 104:518, 2000. (2) W. C. Snyder and H. N. Hansen. Am. J. Bot. 27:64, 1940.

Early establishment response of different Pinus nigra ssp. salzmanii seed sources on contrasting environments: Implications for future reforestation programs and assisted population migration

Forest restoration constitutes an important issue within adaptive environmental management for climate change at global scale. However, effective implementation of these programs can only be achieved by revising current seed transfer guidelines, as they lack inherent spatial and temporal dynamics associated with climate change. In this sense, provenance trials may provide key information on the relative performance of different populations and/or genotypes under changing ecological conditions. This study addresses a methodological approach to evaluate early plantation performance and the consequent phenotypic plasticity and the pattern of the adaptation of different seed sources in contrasting environments. To this end, six seed sources of Salzmann pine were tested at three contrasting trial sites testing a hypothetical assisted population migration. Adaptation at each site was assessed through Joint Regression and Additive Main effect and Multiplication Interaction (AMMI) models. Most of the observed variation was attributed to the environment (above 90% for all traits), even so genotype and genotype by environment interaction (GxE) were significant. Seedlings out-planted under better site conditions did not differ in survival but in height growth. However, on sites with higher constraints, survival differed among seed sources and diameter growth was high. The adaptation analyses (AMMI) indicated that the cold-continental seed source 'Soria' performed as a generalist seed source, whereas 'Cordilleras Béticas', the southernmost seed source, was more adapted to harsh environments (frost and drought) in terms of survival. The results supported partially the hypothesis that assisted migration of seed sources makes sense within limited transfer distances, and this was reinforced by the GxE results. The present study could be valuable to address adaptive transfer of seedings in ecological restoration and to determine the suitable seed sources for reforestation programs and assisted population migration under climatic changes. The reported results are based on 3 years' data and need to be considered in this context.

Ionization fraction and the enhanced sulfur chemistry in Barnard 1

CONTEXT

Barnard B1b has revealed as one of the most interesting globules from the chemical and dynamical point of view. It presents a rich molecular chemistry characterized by large abundances of deuterated and complex molecules. Furthermore, it hosts an extremely young Class 0 object and one candidate to First Hydrostatic Core (FHSC) proving the youth of this star forming region.

AIMS

Our aim is to determine the cosmic ray ionization rate, [Formula: see text], and the depletion factors in this extremely young star forming region. These parameteres determine the dynamical evolution of the core.

METHODS

We carried out a spectral survey towards Barnard 1b as part of the IRAM Large program ASAI using the IRAM 30-m telescope at Pico Veleta (Spain). This provided a very complete inventory of neutral and ionic C-, N- and S- bearing species with, up to our knowledge, the first secure detections of the deuterated ions DCS+ and DOCO+. We use a state-of-the-art pseudo-time-dependent gas-phase chemical model that includes the ortho and para forms of [Formula: see text] and [Formula: see text] to determine the local value of the cosmic ray ionization rate and the depletion factors.

RESULTS

Our model assumes n(H2)=105 cm-3 and T k =12 K, as derived from our previous works. The observational data are well fitted with ζH2 between 3×10-17 s-1 and 10-16 s-1, and the following elemental abundances: O/H=3 10-5, N/H=6.4-8 10-5, C/H=1.7 10-5 and S/H between 6.0 10-7 and 1.0 10-6. The large number of neutral/protonated species detected, allows us to derive the elemental abundances and cosmic ray ionization rate simultaneously. Elemental depletions are estimated to be ~10 for C and O, ~1 for N and ~25 for S.

CONCLUSIONS

Barnard B1b presents similar depletions of C and O than those measured in pre-stellar cores. The depletion of sulfur is higher than that of C and O but not as extreme as in cold cores. In fact, it is similar to the values found in some bipolar outflows, hot cores and photon-dominated regions. Several scenarios are discussed to account for these peculiar abundances. We propose that it is the consequence of the initial conditions (important outflows and enhanced UV fields in the surroundings) and a rapid collapse (~0.1 Myr) that permits to maintain most S- and N-bearing species in gas phase to great optical depths. The interaction of the compact outflow associated with B1b-S with the surrounding material could enhance the abundances of S-bearing molecules, as well.

Experimental intervention study about recognition of erythroplakia by undergraduate dental students

The aim of this study was to assess the efficacy of an examiners' training programme applied to identification of erythroplakia, which undergraduate dental students have found particularly difficult. An experimental group of 5th year undergraduate dental students received a pictorial handout with diagnostic criteria for oral red lesions and two, one hour-long diagnostic seminars in which oral erythroplakia was discussed, together with other red lesions with similar clinical appearance. Three months later a set of 16 photographic slides depicting previously pathologically diagnosed red lesions were projected. Sensitivity, specificity and agreement were all higher for the experimental group compared to a control group. It is suggested that teaching procedures using slides could be useful for training future examiners at recognizing oral erythroplakias.