Genetic variation in prehistoric Sardinia

We sampled teeth from 53 ancient Sardinian (Nuragic) individuals who lived in the Late Bronze Age and Iron Age, between 3,430 and 2,700 years ago. After eliminating the samples that, in preliminary biochemical tests, did not show a high probability to yield reproducible results, we obtained 23 sequences of the mitochondrial DNA control region, which were associated to haplogroups by comparison with a dataset of modern sequences. The Nuragic samples show a remarkably low genetic diversity, comparable to that observed in ancient Iberians, but much lower than among the Etruscans. Most of these sequences have exact matches in two modern Sardinian populations, supporting a clear genealogical continuity from the Late Bronze Age up to current times. The Nuragic populations appear to be part of a large and geographically unstructured cluster of modern European populations, thus making it difficult to infer their evolutionary relationships. However, the low levels of genetic diversity, both within and among ancient samples, as opposed to the sharp differences among modern Sardinian samples, support the hypothesis of the expansion of a small group of maternally related individuals, and of comparatively recent differentiation of the Sardinian gene pools. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Hypothermia modulates circadian clock gene expression in lizard peripheral tissues

The molecular mechanisms whereby the circadian clock responds to temperature changes are poorly understood. The ruin lizard Podarcis sicula has historically proven to be a valuable vertebrate model for exploring the influence of temperature on circadian physiology. It is an ectotherm that naturally experiences an impressive range of temperatures during the course of the year. However, no tools have been available to dissect the molecular basis of the clock in this organism. Here, we report the cloning of three lizard clock gene homologs (Period2, Cryptochrome1, and Clock) that have a close phylogenetic relationship with avian clock genes. These genes are expressed in many tissues and show a rhythmic expression profile at 29 degrees C in light-dark and constant darkness lighting conditions, with phases comparable to their mammalian and avian counterparts. Interestingly, we show that at low temperatures (6 degrees C), cycling clock gene expression is attenuated in peripheral clocks with a characteristic increase in basal expression levels. We speculate that this represents a conserved vertebrate clock gene response to low temperatures. Furthermore, these results bring new insight into the issue of whether circadian clock function is compatible with hypothermia.     

UFP-101 antagonizes the spinal antinociceptive effects of nociceptin/orphanin FQ: behavioral and electrophysiological studies in mice

Nociceptin/orphanin FQ (N/OFQ) modulates various biological functions, including nociception, via selective stimulation of the N/OFQ peptide receptor (NOP). Here we used the NOP selective antagonist UFP-101 to characterize the receptor involved in the spinal antinociceptive effects of N/OFQ evaluated in the mouse tail withdrawal assay and to investigate the mechanism underlying this action by assessing excitatory postsynaptic currents (EPSC) in laminas I and II of the mouse spinal cord dorsal horn with patch-clamp techniques. Intrathecal (i.t.) injection of N/OFQ in the range of 0.1-10 nmol produced a dose dependent antinociceptive effect, which was prevented by UFP-101, but not by naloxone. In contrast the antinociceptive effect of the mu-opioid peptide receptor agonist endomorphin-1 was blocked by naloxone but not by UFP-101. Moreover, N/OFQ and endomorphin-1 induced a significant antinociceptive effect in wild type mice while in mice knockout for the NOP receptor gene only endomorphin-1 was found to be active. In mouse spinal cord slices 1 microM N/OFQ reduced EPSC to 60+/-4% of control values. This inhibitory effect was reversed in a concentration dependent manner by UFP-101 (pA2 value 6.44). The present results demonstrate that N/OFQ-induced spinal antinociception in vivo and inhibition of spinal excitatory transmission in vitro are mediated by receptors of the NOP type.     

Succinate causes pathological cardiomyocyte hypertrophy through GPR91 activation

Background

Succinate is an intermediate of the citric acid cycle as well as an extracellular circulating molecule, whose receptor, G protein-coupled receptor-91 (GPR91), was recently identified and characterized in several tissues, including heart. Because some pathological conditions such as ischemia increase succinate blood levels, we investigated the role of this metabolite during a heart ischemic event, using human and rodent models.

Results

We found that succinate causes cardiac hypertrophy in a GPR91 dependent manner. GPR91 activation triggers the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), the expression of calcium/calmodulin dependent protein kinase IIδ (CaMKIIδ) and the translocation of histone deacetylase 5 (HDAC5) into the cytoplasm, which are hypertrophic-signaling events. Furthermore, we found that serum levels of succinate are increased in patients with cardiac hypertrophy associated with acute and chronic ischemic diseases.

Conclusions

These results show for the first time that succinate plays an important role in cardiomyocyte hypertrophy through GPR91 activation, and extend our understanding of how ischemia can induce hypertrophic cardiomyopathy.

     

Urinary Estrogen Metabolites and Self-Reported Infertility in Women Infected with Schistosoma haematobium

Background

Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens.

Methodology/Principal Findings

A cross-sectional study was undertaken of female residents of a region in Bengo province, Angola, endemic for schistosomiasis haematobia. Ninety-three women and girls, aged from two (parents interviewed) to 94 years were interviewed on present and previous urinary, urogenital and gynecological symptoms and complaints. Urine was collected from the participants for egg-based parasitological assessment of schistosome infection, and for liquid chromatography diode array detection electron spray ionization mass spectrometry (LC/UV-DAD/ESI-MSn) to investigate estrogen metabolites in the urine. Novel estrogen-like metabolites, potentially of schistosome origin, were detected in the urine of participants who were positive for eggs of S. haematobium, but not detected in urines negative for S. haematobium eggs. The catechol-estrogens/ DNA adducts were significantly associated with schistosomiasis (OR 3.35; 95% CI 2.32–4.84; P≤0.001). In addition, presence of these metabolites was positively associated with infertility (OR 4.33; 95% CI 1.13–16.70; P≤0.05).

Conclusions/Significance

Estrogen metabolites occur widely in diverse metabolic pathways. In view of the statistically significant association between catechol-estrogens/ DNA adducts and self-reported infertility, we propose that an estrogen-DNA adduct mediated pathway in S. haematobium-induced ovarian hormonal deregulation could be involved. In addition, the catechol-estrogens/ DNA adducts described here represent potential biomarkers for schistosomiasis haematobia.     

Cardiac Impairment Evaluated by Transesophageal Echocardiography and Invasive Measurements in Rats Undergoing Sinoaortic Denervation

Background

Sympathetic hyperactivity may be related to left ventricular (LV) dysfunction and baro- and chemoreflex impairment in hypertension. However, cardiac function, regarding the association of hypertension and baroreflex dysfunction, has not been previously evaluated by transesophageal echocardiography (TEE) using intracardiac echocardiographic catheter.

Methods and Results

We evaluated exercise tests, baroreflex sensitivity and cardiovascular autonomic control, cardiac function, and biventricular invasive pressures in rats 10 weeks after sinoaortic denervation (SAD). The rats (n = 32) were divided into 4 groups: 16 Wistar (W) with (n = 8) or without SAD (n = 8) and 16 spontaneously hypertensive rats (SHR) with (n = 8) or without SAD (SHRSAD) (n = 8). Blood pressure (BP) and heart rate (HR) did not change between the groups with or without SAD; however, compared to W, SHR groups had higher BP levels and BP variability was increased. Exercise testing showed that SHR had better functional capacity compared to SAD and SHRSAD. Echocardiography showed left ventricular (LV) concentric hypertrophy; segmental systolic and diastolic biventricular dysfunction; indirect signals of pulmonary arterial hypertension, mostly evident in SHRSAD. The end-diastolic right ventricular (RV) pressure increased in all groups compared to W, and the end-diastolic LV pressure increased in SHR and SHRSAD groups compared to W, and in SHRSAD compared to SAD.

Conclusions

Our results suggest that baroreflex dysfunction impairs cardiac function, and increases pulmonary artery pressure, supporting a role for baroreflex dysfunction in the pathogenesis of hypertensive cardiac disease. Moreover, TEE is a useful and feasible noninvasive technique that allows the assessment of cardiac function, particularly RV indices in this model of cardiac disease.     

Distribution of MT1 Melatonin Receptor Promoter-Driven RFP Expression in the Brains of BAC C3H/HeN Transgenic Mice

The pineal hormone melatonin activates two G-protein coupled receptors (MT₁ and MT₂) to regulate in part biological functions. The MT₁ and MT₂ melatonin receptors are heterogeneously distributed in the mammalian brain including humans. In the mouse, only a few reports have assessed the expression of the MT₁ melatonin receptor expression using 2-iodomelatonin binding, in situ hybridization and/or polymerase chain reaction (PCR). Here, we described a transgenic mouse in which red fluorescence protein (RFP) is expressed under the control of the endogenous MT₁ promoter, by inserting RFP cDNA at the start codon of MTNR1a gene within a bacterial artificial chromosome (BAC) and expressing this construct as a transgene. The expression of RFP in the brain of this mouse was examined either directly under a fluorescent microscope or immunohistochemically using an antibody against RFP (RFP-MT₁). RFP-MT₁ expression was observed in many brain regions including the subcommissural organ, parts of the ependyma lining the lateral and third ventricles, the aqueduct, the hippocampus, the cerebellum, the pars tuberalis, the habenula and the habenula commissure. This RFP-MT₁ transgenic model provides a unique tool for studying the distribution of the MT₁ receptor in the brain of mice, its cell-specific expression and its function in vivo.     

Functional Characterization of drim2, the Drosophila melanogaster Homolog of the Yeast Mitochondrial Deoxynucleotide Transporter

The CG18317 gene (drim2) is the Drosophila melanogaster homolog of the Saccharomyces cerevisiae Rim2 gene, which encodes a pyrimidine (deoxy)nucleotide carrier. Here, we tested if the drim2 gene also encodes for a deoxynucleotide transporter in the fruit fly. The protein was localized to mitochondria. Drosophila S2R⁺ cells, silenced for drim2 expression, contained markedly reduced pools of both purine and pyrimidine dNTPs in mitochondria, whereas cytosolic pools were unaffected. In vivo drim2 homozygous knock-out was lethal at the larval stage, preceded by the following: (i) impaired locomotor behavior; (ii) decreased rates of oxygen consumption, and (iii) depletion of mtDNA. We conclude that the Drosophila mitochondrial carrier dRIM2 transports all DNA precursors and is essential to maintain mitochondrial function.