Adenosine and TNF-alpha exert similar inotropic effect on heart cultures, suggesting a cardioprotective mechanism against hypoxia

When cardiomyocytes were subjected to hypoxia, tumor necrosis factor-α (TNF-α; 3-50 ng/ml) or adenosine (1-100 μM), decreased hypoxic damage as was detected by lactate dehydrogenase (LDH) release, MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) absorbance, ROS (reactive oxygen species) measurement or desmin immunostaining. This cardioprotection was not prevented in TNF-α-treated cultures by 5-hydroxydecanoic acid (5-HD). Our aim was to elucidate whether adenosine and TNF-α mediate a similar protective mechanism against hypoxia in primary heart cultures and in H9c2 cardiomyocytes. Adenosine and TNF-α are known for their negative inotropic effects on the heart. We have suggested that deoxyglucose uptake reflects heart contractility in cell cultures; therefore, we assayed its accumulation under various conditions. Treatment for 20 min with adenosine, R-PIA [(−)-N(6)-phenylisopropyladenosine] (10 μM), or TNF-α reduced ³H-deoxyglucose uptake in primary heart cultures and also in H9c2 cardiomyocytes by 30-50%. Isoproterenol accelerated ³H-deoxyglucose uptake by 50%. Adenosine, R-PIA, or TNF-α attenuated the stimulatory effect of isoproterenol on ³H-deoxyglucose uptake to control levels. Hypoxia reduced ³H-deoxyglucose uptake by 50%, as in the treatment of the hypoxic cultures with TNF-α or adenosine. Glibenclamide (2 μM), 5-HD (300 μM), or diazoxide (50 μM) increased ³H-deoxyglucose uptake by 50-80%. Adenosine (100 μM) and TNF-α (50 ng/ml) stimulated ⁸⁶Rb efflux. Glibenclamide attenuated this effect. We demonstrate that TNF-α, like adenosine, accelerated Ca²⁺ uptake into the sarcoplasmic reticulum (SR) by 50-100% and therefore prevented cardiomyocyte Ca²⁺ overload. Our findings further suggest that TNF-α, as well as adenosine, may mediate an adaptive effect in the heart by preventing Ca²⁺ overload via activation of SR Ca-ATPase (SERCA₂a).     

Modern hunting behavior in the early Middle Paleolithic: faunal remains from Misliya Cave, Mount Carmel, Israel

Understanding the behavioral adaptations and subsistence strategies of Middle Paleolithic humans is critical in the debate over the evolution and manifestations of modern human behavior. The study of faunal remains plays a central role in this context. Until now, the majority of Levantine archaeofaunal evidence was derived from late Middle Paleolithic sites. The discovery of faunal remains from Misliya Cave, Mount Carmel, Israel (>200 ka), allowed for detailed taphonomic and zooarchaeological analyses of these early Middle Paleolithic remains. The Misliya Cave faunal assemblage is overwhelmingly dominated by ungulate taxa. The most common prey species is the Mesopotamian fallow deer (Dama mesopotamica), followed closely by the mountain gazelle (Gazella gazella). Some aurochs (Bos primigenius) remains are also present. Small-game species are rare. The fallow deer mortality pattern is dominated by prime-aged individuals. A multivariate taphonomic analysis demonstrates (1) that the assemblage was created solely by humans occupying the cave and was primarily modified by their food-processing activities; and (2) that gazelle carcasses were transported complete to the site, while fallow deer carcasses underwent some field butchery. The new zooarchaeological data from Misliya Cave, particularly the abundance of meat-bearing limb bones displaying filleting cut marks and the acquisition of prime-age prey, demonstrate that early Middle Paleolithic people possessed developed hunting capabilities. Thus, modern large-game hunting, carcass transport, and meat-processing behaviors were already established in the Levant in the early Middle Paleolithic, more than 200 ka ago.     

Autoantibody epitope spreading in the pre-clinical phase predicts progression to rheumatoid arthritis

Rheumatoid arthritis (RA) is a prototypical autoimmune arthritis affecting nearly 1% of the world population and is a significant cause of worldwide disability. Though prior studies have demonstrated the appearance of RA-related autoantibodies years before the onset of clinical RA, the pattern of immunologic events preceding the development of RA remains unclear. To characterize the evolution of the autoantibody response in the preclinical phase of RA, we used a novel multiplex autoantigen array to evaluate development of the anti-citrullinated protein antibodies (ACPA) and to determine if epitope spread correlates with rise in serum cytokines and imminent onset of clinical RA. To do so, we utilized a cohort of 81 patients with clinical RA for whom stored serum was available from 1-12 years prior to disease onset. We evaluated the accumulation of ACPA subtypes over time and correlated this accumulation with elevations in serum cytokines. We then used logistic regression to identify a profile of biomarkers which predicts the imminent onset of clinical RA (defined as within 2 years of testing). We observed a time-dependent expansion of ACPA specificity with the number of ACPA subtypes. At the earliest timepoints, we found autoantibodies targeting several innate immune ligands including citrullinated histones, fibrinogen, and biglycan, thus providing insights into the earliest autoantigen targets and potential mechanisms underlying the onset and development of autoimmunity in RA. Additionally, expansion of the ACPA response strongly predicted elevations in many inflammatory cytokines including TNF-α, IL-6, IL-12p70, and IFN-γ. Thus, we observe that the preclinical phase of RA is characterized by an accumulation of multiple autoantibody specificities reflecting the process of epitope spread. Epitope expansion is closely correlated with the appearance of preclinical inflammation, and we identify a biomarker profile including autoantibodies and cytokines which predicts the imminent onset of clinical arthritis.     

Alopecia, neurological defects, and endocrinopathy syndrome caused by decreased expression of RBM28, a nucleolar protein associated with ribosome biogenesis

Single-gene disorders offer unique opportunities to shed light upon fundamental physiological processes in humans. We investigated an autosomal-recessive phenotype characterized by alopecia, progressive neurological defects, and endocrinopathy (ANE syndrome). By using homozygosity mapping and candidate-gene analysis, we identified a loss-of-function mutation in RBM28, encoding a nucleolar protein. RBM28 yeast ortholog, Nop4p, was previously found to regulate ribosome biogenesis. Accordingly, electron microscopy revealed marked ribosome depletion and structural abnormalities of the rough endoplasmic reticulum in patient cells, ascribing ANE syndrome to the restricted group of inherited disorders associated with ribosomal dysfunction.     

Filamin A is a novel caveolin-1-dependent target in IGF-I-stimulated cancer cell migration

Caveolin-1 is an essential structural constituent of caveolae which is involved in regulation of mitogenic signaling and oncogenesis. Caveolin-1 has been implicated in cell migration but its exact role and mechanism of action in this process remained obscure. We have previously reported that expression of caveolin-1 in stably transfected MCF-7 human breast cancer (MCF-7/Cav1) cells up-regulates phosphorylation of a putative Akt substrate protein, designated pp340 [D. Ravid, S. Maor, H. Werner, M. Liscovitch, Caveolin-1 inhibits cell detachment-induced p53 activation and anoikis by upregulation of insulin-like growth factor-I receptors and signaling, Oncogene 24 (2005) 1338-1347.]. We now show, using differential detergent extraction, SDS-PAGE and mass spectrometry, that the major protein in the pp340 band is the actin filament cross-linking protein filamin A. The identity of pp340 as filamin A was confirmed by immunoprecipitation of pp340 with specific filamin A antibodies. RT-PCR, flow cytometry and Western blot analyses show that filamin A mRNA and protein levels are respectively 3.5- and 2.5-fold higher in MCF-7/Cav1 cells than in MCF-7 cells. Basal filamin A phosphorylation on Ser-2152, normalized to total filamin A levels, is 7.8-fold higher in MCF-7/Cav1 than in MCF-7 cells. Insulin-like growth factor-I (IGF-I) stimulates phosphorylation of filamin A on Ser-2152 in MCF-7 cells and further enhances Ser-2152 phosphorylation over its already high basal level in MCF-7/Cav1 cells. The effect of IGF-I is inhibited by the PI3K inhibitor wortmannin, indicating that IGF-I-stimulated phosphorylation of filamin A occurs via the PI3K/Akt pathway. Co-immunoprecipitation experiments have confirmed a previous report showing that filamin A and caveolin-1 co-exist in a complex and have revealed the presence of active phospho-Akt in this complex. Ser-2152 phosphorylation of filamin A has been implicated in cancer cell migration. Accordingly, caveolin-1 expression dramatically enhances IGF-I-dependent MCF-7 cell migration. These data indicate that caveolin-1 specifies filamin A as a novel target for Akt-mediated filamin A Ser-2152 phosphorylation thus mediating the effects of caveolin-1 on IGF-I-induced cancer cell migration.     

Learning affects mate choice in female fruit flies

Learning in the context of mate choice can influence sexualselection and speciation. Relatively little work, however, hasbeen conducted on the role of learning in the context of matechoice, and this topic has been mostly ignored in insects eventhough insects have served as a prime model system in researchon sexual selection and incipient speciation. Extending recentwork indicating apparently adaptive learning in the contextof sexual behavior by male fruit flies (Drosophila melanogaster),I tested for the effect of learning on mate choice by femalefruit flies. Compared to young virgin females that experiencedcourtship by large males, young virgin females that experiencedcourtship by small males were more likely to mate with smalland large males in a test conducted a day after the experiencephase. These results, which are the first clear empirical demonstrationof learning in the context of mate choice by female insects,lay the foundation for research on the role of learning in insectsexual selection and speciation.     

Avian migrants adjust migration in response to environmental conditions en route

The onset of migration in birds is assumed to be primarily under endogenous control in long-distance migrants. Recently, climate changes appear to have been driving a rapid change in breeding area arrival. However, little is known about the climatic factors affecting migratory birds during the migration cycle, or whether recently reported phenological changes are caused by plastic behavioural responses or evolutionary change. Here, we investigate how environmental conditions in the wintering areas as well as en route towards breeding areas affect timing of migration. Using data from 1984 to 2004 covering the entire migration period every year from observatories located in the Middle East and northern Europe, we show that passage of the Sahara Desert is delayed and correlated with improved conditions in the wintering areas. By contrast, migrants travel more rapidly through Europe, and adjust their breeding area arrival time in response to improved environmental conditions en route. Previous studies have reported opposing results from a different migration route through the Mediterranean region (Italy). We argue that the simplest explanation for different phenological patterns at different latitudes and between migratory routes appears to be phenotypic responses to spatial variability in conditions en route.     

Lipoprotein-associated phospholipase A2, and subsequent cardiovascular events and mortality among patients with coronary heart disease

Objective: The objective of this study is to evaluate the relevance of Lp-PLA₂ to risk prediction among coronary heart disease (CHD) patients.

Methods: Lp-PLA₂ activity was measured in 2538 CHD patients included in the Bezafibrate Infarction Prevention (BIP) study.

Results: Adjusting for patient characteristics and traditional risk factors, 1 standard deviation of Lp-PLA₂ was associated with a hazard ratio (HR) of 1.12 (95% confidence interval (CI): 1.00–1.25) for mortality and 1.03 (0.93–1.14) for cardiovascular events. Lp-PLA₂ did not significantly improve model discrimination, or calibration nor result in noteworthy reclassification.

Conclusions: Our results do not support added value of Lp-PLA₂ for predicting cardiovascular events or mortality among CHD patients beyond traditional risk factor.     

Molecular engineering of cyclic α-diketone aromatic ring bichromophoric molecules for studies of intramolecular electronic energy transfer

The design, structures and spectral properties of a number of bichromophoric molecules are presented. These bichromophoric molecules are composed of an aromatic ring connected by two methylene chains to an -diketone moiety. Both absorption and emission spectra can be attributed to a superposition of the individual spectra of the separate chromophores. The critical transfer radius for electronic energy transfer from the aromatic (donor) chromophore to the -diketone (acceptor) chromophore was calculated from the spectral overlap between the fluorescence spectrum of the aromatic moiety and the absorption spectrum of the -diketone moiety. The results show that this series of molecules is well suited for a mechanistic study of short-range intramolecular electronic energy transfer.     

A study of the dynamic properties of actomyosin systems by quasi-elastic light scattering

A laser light source and a digital autocorrelator were employed in the study of the molecular dynamics of acto-heavy meromyosin during the splitting of ATP. Low protein concentrations were used, so that molecular and not gel properties were evident. The addition of Mg²⁺ to acto-heavy meromyosin solutions in the presence of ATP caused a marked widening of the spectrum at high scattering angles. No such change was observed when chemically inactivated heavy meromyosin was used, when actin was cross-linked or when the proteins were in a high ionic strength solution. The data can be interpreted in terms of pronounced change in flexibility of acto-heavy meromyosin induced by active mechanochemical coupling.