A new D₂ dopamine receptor agonist allosterically modulates A(2A) adenosine receptor signalling by interacting with the A(2A)/D₂ receptor heteromer

The structural and functional interaction between D₂ dopamine receptor (DR) and A_2A adenosine receptor (AR) has suggested these two receptors as a pharmacological target in pathologies associated with dopamine dysfunction, such as Parkinson's disease. In transfected cell lines it has been demonstrated the activation of D₂DR induces a significant negative regulation of A_2AAR-mediated responses, whereas few data are at now available about the regulation of A_2AAR by D₂DR agonists at receptor recognition site. In this work we confirmed that in A_2AAR/D₂DR co-transfected cells, these receptors exist as homo- and hetero-dimers. The classical D₂DR agonists were able to negatively modulate both A_2AAR affinity and functionality. These effects occurred even if any significant changes in A_2AAR/D₂DR energy transfer interaction could be detected in BRET experiments.Since the development of new molecules able to target A_2A/D₂ dimers may represent an attractive tool for innovative pharmacological therapy, we also identified a new small molecule, 3-(3,4-dimethylphenyl)-1-(2-piperidin-1-yl)ethyl)piperidine (compound 1), full agonist of D₂DR and modulator of A_2A-D₂ receptor dimer. This compound was able to negatively modulate A_2AAR binding properties and functional responsiveness in a manner comparable to classical D₂R agonists. In contrast to classical agonists, compound 1 led to conformational changes in the quaternary structure in D₂DR homomers and heteromers and induced A_2AAR/D₂DR co-internalization. These results suggest that compound 1 exerts a high control of the function of heteromers and could represent a starting point for the development of new drugs targeting A_2AAR/D₂ DR heteromers.     

Association between the epidermal growth factor rs4444903 G/G genotype and advanced fibrosis at a young age in chronic hepatitis C

Background

The epidermal growth factor (EGF) rs4444903 A > G polymorphism has been associated with the development of liver cancer, which commonly complicates cirrhosis of viral origin; however, whether this polymorphism might be associated with fibrosis progression in chronic viral hepatitis is unknown. The present study was performed to assess the allelic and genotypic frequencies of the rs4444903 A > G polymorphism in patients with chronic hepatitis C virus HCV infection and to ascertain whether this polymorphism might be an independent predictor of the degree of fibrosis.

Methods

An RFLP-PCR technique was used to genotype 645 patients (211 with cirrhosis); 528 were referred for the diagnosis and treatment of chronic hepatitis C, and 117 were transplanted for HCV-related end stage liver disease. A group of 428 healthy subjects served as a control. All the subjects were of Caucasian ethnicity.

Results

The EGF rs4444903 A > G polymorphism genotype frequencies in HCV chronic infected patients were as follows: A/A = 227 (35.3%), A/G = 328 (50.9%), and G/G = 90 (14.8%). Genotype frequencies were found to differ between patients with an Ishak staging score ? 2 (A/A = 117, A/G = 157, G/G = 34) and patients with a score > 2 (A/A = 110, A/G = 171, G/G = 56, p = 0.038). A highly significant linear relationship between increasing stage scores and EGF genotype was detected in younger patients (A/A: 2.02 ± 0.18, A/G: 2.55 ± 0.17, G/G: 3.00 ± 0.32, p = 0.008). However, no significant association was detected between the stage score and EGF genotype in older patients (A/A: 3.79 ± 0.19, A/G: 3.64 ± 0.15, G/G: 3.98 ± 0.30 p = 0.579).

Conclusions

The EGF rs4444903 A > G polymorphism may facilitate liver fibrosis progression in Caucasian patients with chronic hepatitis C, especially in younger patients.     

Scratching around mating: factors affecting anxiety in wild Lemur catta

Scratching has been successfully used to detect anxiety, a proxy for stress, in primates, from strepsirrhines to Homo sapiens. Here, we investigated the fluctuation of scratching in Lemur catta during the mating season. In particular we evaluated whether scratching (1) varied according to sex and rank differences, (2) increased in the period of maximum stress (around the mating days), and (3) was reduced by grooming. At Berenty (South Madagascar), we followed two lemur groups (23 adult/subadult individuals) and gathered data on self-scratching, aggression, and grooming. Based on perineal area features, we recognized two periods: low swelling (LS), with no estrus female, and high swelling (HS), when at least one female was in estrus. We predicted that aggressive behaviors and anxiety-related scratching would covary. Indeed, scratching peaked in HS, when aggression was also highest. In agreement with previous literature, this result suggests that conflicts around estrus days may raise anxiety levels in the social group. We expected scratching levels to be highest in males because they aggressively compete for females and are subject to mate choice and repeated attacks by dominant females. Instead, the scratching rates were similar in males and females, probably because the high competition, which involves both sexes, dampened intersexual differences. In contrast to our prediction, scratching was not rank dependent, probably because animal ranking positions changed from LS to HS. Finally, we showed that, in ring-tailed lemurs, as well as in other primates, scratching decreases after reciprocal grooming in both periods. This finding provides the first evidence that grooming could assist in reducing anxiety in strepsirrhines.     

Role of neurotrophins on dermal fibroblast survival and differentiation

Neurotrophins (NTs) belong to a family of growth factors that play a critical role in the control of skin homeostasis. NTs act through the low-affinity receptor p75NTR and the high-affinity receptors TrkA, TrkB, and TrkC. Here we show that dermal fibroblasts (DF) and myofibroblasts (DM) synthesize and secrete all NTs and express NT receptors. NTs induce differentiation of DF into DM, as shown by the expression of α-SMA protein. The Trk inhibitor K252a, TrkA/Fc, TrkB/Fc, or TrkC/Fc chimera prevents DF and DM proliferation. In addition, p75NTR siRNA inhibits DF proliferation, indicating that both NT receptors mediate DF proliferation induced by endogenous NTs. Autocrine NTs also induce DF migration through p75NTR and Trk, as either silencing of p75NTR or Trk/Fc chimeras prevent this effect, in absence of exogenous NTs. Finally, NGF or BDNF statistically increase the tensile strength in a dose dependent manner, as measured in a collagen gel through the GlaSbox device. Taken together, these results indicate that NTs exert a critical role on fibroblast and could be involved in tissue re-modeling and wound healing.     

Flexible and conservative features of social systems in tufted capuchin monkeys: comparing the socioecology of Sapajus libidinosus and Sapajus nigritus

Socioecological models assume that primates adapt their social behavior to ecological conditions, and predict that food availability and distribution, predation risk and risk of infanticide by males affect patterns of social organization, social structure and mating system of primates. However, adaptability and variation of social behavior may be constrained by conservative adaptations and by phylogenetic inertia. The comparative study of closely related species can help to identify the relative contribution of ecological and of genetic determinants to primate social systems. We compared ecological features and social behavior of two species of the genus Sapajus, S. nigritus in Carlos Botelho State Park, an area of Atlantic Forest in S?o Paulo state, and S. libidinosus in Fazenda Boa Vista, a semi-arid habitat in Piauí state, Brazil. S. libidinosus perceived higher predation risk and fed on clumped, high quality, and usurpable resources (fruits) all year round, whereas S. nigritus perceived lower predation risk and relied on evenly distributed, low-quality food sources (leaves) during periods of fruit shortage. As predicted by socioecology models, S. libidinosus females were philopatric and established linear and stable dominance hierarchies, coalitions, and grooming relationships. S. nigritus females competed less often, and could transfer between groups, which might explain the lack of coalitions and grooming bonds among them. Both populations presented similar group size and composition and the same polygynous mating system. The species differed from each other in accordance with differences in the characteristics of their main food sources, as predicted by socioecological models, suggesting that phylogenetic inertia does not constrain social relationships established among female Sapajus. The similarity in mating systems indicates that this element of the social system is not affected by ecological variables and thus, is a more conservative behavioral feature of the genus Sapajus.     

Low concentration of LatB dramatically changes the microtubule organization and the timing of vegetative nucleus/generative cell entrance in tobacco pollen tubes

Low concentration of LatB inhibits not only the actin polymerization, but also induces profound alteration of MT distribution in pollen tubes of Nicotiana tabacum. The short randomly oriented MTs in the apical and subapical regions, became organized as bundles forming subapical rings or basket-like structures, surrounding the apex. Moreover, the depolymerization of AFs in the cortical regions of the apex and subapical region affects the timing of entrance of the vegetative nucleus and generative cell into the pollen tube.     

An NMR-based metabolomic approach to identify the botanical origin of honey

NMR can be used in food analysis for origin discrimination and biomarker discovery using a metabolomic approach. Here, we present an example of this strategy to discriminate honey samples of different botanical origins. The NMR spectra of 353 chloroform extracts of selected honey samples were analyzed to detect possible markers of their floral origin. Six monofloral Italian honey types (acacia, linden, orange, eucalyptus, chestnut, and honeydew) were analyzed together with polyfloral samples. Specific markers were identified for each monofloral origin: two markers for acacia (chrysin and pinocembrin), one for chestnut (??-LACT-3-PKA), two for orange (8-hydroxylinalool and caffeine), one for eucalyptus (dehydrovomifoliol), one for honeydew (a diacylglycerilether) and two for linden (4-(1-hydroxy-1-methylethyl)cyclohexa-1,3-diene-carboxylic acid and 4-(1-methylethenyl)cyclohexa-1,3-diene-carboxylic acid). An NMR-based metabolomic approach that used O2PLS-DA multivariate data analysis allowed us to discriminate the different types of honey. Two different classifiers were built based on different multivariate techniques. The high precision of the classification obtained suggests that this approach could be useful to develop generally applicable metabolomic tools to discriminate the origin of honey samples.     

Neglected markers: altered serum proteome in murine models of disease

More than a decade ago our groups pioneered the analysis of serum proteins of laboratory animals with up-to-date proteomic techniques. We were, and still are, convinced that conforming animal procedures to the minimally invasive approaches typical of clinical biochemistry focuses attention on the actual conditions under which any finding arrived at on animal models of disease may eventually be applied to human patients for screening/diagnosis. We are also convinced that, besides the proteins present in trace level as a result of tissue leakage during disorders affecting specific peripheral organs, changes in the concentration of some of the major serum proteins as part of an acute-phase response may be taken as biological end-points during a number of experimental procedures. When reviewing literature data about proteomic investigations on plasma or serum of mice, we realized that not much work has been done in the direction we favor. In addition, we noticed that sometimes information about serum proteome has been coarsely treated and in a few cases even misunderstood/misused. In the following, we present current findings on serum/plasma proteome of the laboratory mouse not only under control conditions and during an experimentally induced acute-phase reaction, but also in a number of models of disease, mainly related to cancer and to metabolic disorders.     

Identification of serum proteomic biomarkers for early porcine reproductive and respiratory syndrome (PRRS) infection

ABSTRACT: BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is one of the most significant swine diseases worldwide. Despite its relevance, serum biomarkers associated with early-onset viral infection, when clinical signs are not detectable and the disease is characterized by a weak anti-viral response and persistent infection, have not yet been identified. Surface-enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) is a reproducible, accurate, and simple method for the identification of biomarker proteins related to disease in serum. This work describes the SELDI-TOF MS analyses of sera of 60 PRRSV-positive and 60 PRRSV-negative, as measured by PCR, asymptomatic Large White piglets at weaning. Sera with comparable and low content of hemoglobin (< 4.52 ug/mL) were fractionated in 6 different fractions by anion-exchange chromatography and protein profiles in the mass range 1-200 kDa were obtained with the CM10, IMAC30, and H50 surfaces. RESULTS: A total of 200 significant peaks (p < 0.05) were identified in the initial discovery phase of the study and 47 of them were confirmed in the validation phase. The majority of peaks (42) were up-regulated in PRRSV-positive piglets, while 5 were down-regulated. A panel of 14 discriminatory peaks identified in fraction 1 (pH=9), on the surface CM10, and acquired at low focus mass provided a serum protein profile diagnostic pattern that enabled to discriminate between PRRSV-positive and -negative piglets with a sensitivity and specificity of 77% and 73%, respectively. CONCLUSIONS: SELDI-TOF MS profiling of sera from PRRSV-positive and PRRSV-negative asymptomatic piglets provided a proteomic signature with large scale diagnostic potential for early identification of PRRSV infection in weaning piglets. Furthermore, SELDI-TOF protein markers represent a refined phenotype of PRRSV infection that might be useful for whole genome association studies.