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Sample records for receptor oxtr contributes

  1. Oxytocin Receptor (OXTR) Single Nucleotide Polymorphisms Indirectly Predict Prosocial Behavior Through Perspective Taking and Empathic Concern.

    PubMed

    Christ, Christa C; Carlo, Gustavo; Stoltenberg, Scott F

    2016-04-01

    Engaging in prosocial behavior can provide positive outcomes for self and others. Prosocial tendencies contribute to the propensity to engage in prosocial behavior. The oxytocin receptor gene (OXTR) has also been associated with prosocial tendencies and behaviors. There has been little research, however, investigating whether the relationship between OXTR and prosocial behaviors is mediated by prosocial tendencies. This relationship may also vary among different types of prosocial behavior. The current study examines the relationship between OXTR, gender, prosocial tendencies, and both altruistic and public prosocial behavior endorsement. Students at a midwestern university (N = 398; 89.2% Caucasian; Mage  = 20.76; 26.6% male) provided self-report measures of prosocial tendencies and behaviors and buccal cells for genotyping OXTR polymorphisms. Results indicated that OXTR single nucleotide polymorphism (SNP) rs2268498 genotype significantly predicted empathic concern, whereas gender moderated the association between several other OXTR SNPs and prosocial tendencies. Increased prosocial tendencies predicted increased altruistic prosocial behavior endorsement and decreased public prosocial behavior endorsement. Our findings suggest an association between genetic variation in OXTR and endorsement of prosocial behavior indirectly through prosocial tendencies, and that the pathway is dependent on the type of prosocial behavior and gender.

  2. How Oxytocin Receptor (OXTR) Single Nucleotide Polymorphisms Act on Prosociality: The Mediation Role of Moral Evaluation

    PubMed Central

    Shang, Siyuan; Wu, Nan; Su, Yanjie

    2017-01-01

    Prosociality is related to numerous positive outcomes, and mechanisms underlying individual differences in prosociality have been widely discussed. Recently, research has found converging evidence on the influence of the oxytocin receptor (OXTR) gene on prosociality. Meanwhile, moral reasoning, a key precursor for social behavior, has also been associated with variability in OXTR gene, thus the relationship between OXTR and prosociality is assumed to be mediated by moral evaluation. The current study examines the relationship in question, and includes gender as a potential moderator. Self-reported prosociality on Prosocial Tendencies Measure and evaluation on the moral acceptability of behaviors in stories from 790 Chinese adolescents (32.4% boys) were analyzed for the influence of their OXTR single nucleotide polymorphisms (SNPs). Results showed that SNP at site rs2254298 was indirectly associated with prosocial behaviors via moral evaluation of behaviors, and this effect was moderated by gender. Our findings suggest an indirect association between genetic variations in OXTR and prosociality through moral evaluation, indicating the potential pathway from genetic variability to prosociality through level of moral development. We also provide some evidence that the role of oxytocin system may to some extent depend on gender. These findings may promote our understanding of the genetic and biological roots of prosociality and morality. PMID:28377734

  3. No Association between Oxytocin Receptor (OXTR) Gene Polymorphisms and Experimentally Elicited Social Preferences

    PubMed Central

    Apicella, Coren L.; Cesarini, David; Johannesson, Magnus; Dawes, Christopher T.; Lichtenstein, Paul; Wallace, Björn; Beauchamp, Jonathan; Westberg, Lars

    2010-01-01

    Background Oxytocin (OXT) has been implicated in a suite of complex social behaviors including observed choices in economic laboratory experiments. However, actual studies of associations between oxytocin receptor (OXTR) gene variants and experimentally elicited social preferences are rare. Methodology/Principal Findings We test hypotheses of associations between social preferences, as measured by behavior in two economic games, and 9 single nucleotide polymorphisms (SNPs) of the OXTR gene in a sample of Swedish twins (n = 684). Two standard economic games, the dictator game and the trust game, both involving real monetary consequences, were used to elicit such preferences. After correction for multiple hypothesis testing, we found no significant associations between any of the 9 single nucleotide polymorphisms (SNPs) and behavior in either of the games. Conclusion We were unable to replicate the most significant association reported in previous research between the amount donated in a dictator game and an OXTR genetic variant. PMID:20585395

  4. Association between the oxytocin receptor (OXTR) gene and children's social cognition at 18 months.

    PubMed

    Wade, M; Hoffmann, T J; Wigg, K; Jenkins, J M

    2014-09-01

    At 18 months, children engage in a variety of social behaviors that reflect their nascent ability to understand the intentions of other people (e.g. joint attention, empathy, cooperation and self-recognition). Although numerous contextual factors have been shown to predict social cognition in young children, the genetic underpinnings of social-cognitive traits has been understudied in this age group. Owing to the known effects of oxytocin on adult social cognition and psychopathology, this study hypothesized that variability in the oxytocin receptor gene (OXTR) would be associated with social cognition in children at 18 months. Participants consisted of 350 children (182 males; 168 females) who were part of an ongoing longitudinal study that aimed to assess environmental and genetic contributions to children's cognitive and socio-emotional functioning. At 18 months, social cognition was measured using previously validated and developmentally sensitive tasks assessing children's joint attention, empathy, cooperation and self-recognition. Five potentially functional OXTR variants were genotyped: rs1042778, rs2254298, rs11131149, rs237897 and rs237899. A family-based association design was used to control for population admixture and stratification, and additional non-genomic covariates were controlled. Results showed that variability in rs11131149 was significantly associated with social cognition (P=0.009), with more copies of the major allele related to higher social cognition, and more copies of the minor (risk) allele associated with lower social cognition. A haplotype consisting of rs11131149-rs2254298 was also associated with social cognition (P=0.020). Implications for normative and pathological development are discussed, and key areas for future research are proposed.

  5. ASD and Genetic Associations with Receptors for Oxytocin and Vasopressin—AVPR1A, AVPR1B, and OXTR

    PubMed Central

    Francis, Sunday M.; Kim, Soo-Jeong; Kistner-Griffin, Emily; Guter, Stephen; Cook, Edwin H.; Jacob, Suma

    2016-01-01

    Background: There are limited treatments available for autism spectrum disorder (ASD). Studies have reported significant associations between the receptor genes of oxytocin (OT) and vasopressin (AVP) and ASD diagnosis, as well as ASD-related phenotypes. Researchers have also found the manipulation of these systems affects social and repetitive behaviors, core characteristics of ASD. Consequently, research involving the oxytocin/vasopressin pathways as intervention targets has increased. Therefore, further examination into the relationship between these neuropeptides and ASD was undertaken. In this study, we examined associations between variants in the receptor genes of vasopressin (AVPR1A, AVPR1B), oxytocin (OXTR), and ASD diagnosis along with related subphenotypes. Methods: Probands were assessed using Autism Diagnostic Interview-Revised, Autism Diagnostic Observation Schedule, and clinical DSM-IV-TR criteria. Single nucleotide polymorphisms (SNPs) in AVPR1B and OXTR, and microsatellites in AVPR1A were genotyped in ~200 families with a proband with ASD. Family-based association testing (FBAT) was utilized to determine associations between variants and ASD. Haplotypes composed of OXTR SNPs (i.e., rs53576-rs2254298-rs2268493) were also analyzed due to previously published associations. Results: Using the additive inheritance model in FBAT we found associations between AVPR1B SNPs (rs28632197, p = 0.005, rs35369693, p = 0.025) and diagnosis. As in other studies, OXTR rs2268493 (p = 0.050) was associated with diagnosis. rs2268493 was also associated with ASD subphenotypes of social withdrawal (p = 0.013) and Insistence on Sameness (p = 0.039). Further analyses demonstrated that the haplotype, rs2254298–rs2268493 was found to be significantly associated with diagnosis (A-T; p = 0.026). FBAT was also used to analyze AVPR1A microsatellites (RS1 and RS3). Both length variants were found to be associated with restrictive, repetitive behaviors, but not overall diagnosis

  6. Chimpanzee sociability is associated with vasopressin (Avpr1a) but not oxytocin receptor gene (OXTR) variation.

    PubMed

    Staes, Nicky; Koski, Sonja E; Helsen, Philippe; Fransen, Erik; Eens, Marcel; Stevens, Jeroen M G

    2015-09-01

    The importance of genes in regulating phenotypic variation of personality traits in humans and animals is becoming increasingly apparent in recent studies. Here we focus on variation in the vasopressin receptor gene 1a (Avpr1a) and oxytocin receptor gene (OXTR) and their effects on social personality traits in chimpanzees. We combine newly available genetic data on Avpr1a and OXTR allelic variation of 62 captive chimpanzees with individual variation in personality, based on behavioral assessments. Our study provides support for the positive association of the Avpr1a promoter region, in particular the presence of DupB, and sociability in chimpanzees. This complements findings of previous studies on adolescent chimpanzees and studies that assessed personality using questionnaire data. In contrast, no significant associations were found for the single nucleotide polymorphism (SNP) ss1388116472 of the OXTR and any of the personality components. Most importantly, our study provides additional evidence for the regulatory function of the 5' promoter region of Avpr1a on social behavior and its evolutionary stable effect across species, including rodents, chimpanzees and humans. Although it is generally accepted that complex social behavior is regulated by a combination of genes, the environment and their interaction, our findings highlight the importance of candidate genes with large effects on behavioral variation.

  7. Alcohol and aggressive behavior in men--moderating effects of oxytocin receptor gene (OXTR) polymorphisms.

    PubMed

    Johansson, A; Bergman, H; Corander, J; Waldman, I D; Karrani, N; Salo, B; Jern, P; Algars, M; Sandnabba, K; Santtila, P; Westberg, L

    2012-03-01

    We explored if the disposition to react with aggression while alcohol intoxicated was moderated by polymorphic variants of the oxytocin receptor gene (OXTR). Twelve OXTR polymorphisms were genotyped in 116 Finnish men [aged 18-30, M = 22.7, standard deviation (SD) = 2.4] who were randomly assigned to an alcohol condition in which they received an alcohol dose of 0.7 g pure ethanol/kg body weight or a placebo condition. Aggressive behavior was measured using a laboratory paradigm in which it was operationalized as the level of aversive noise administered to a fictive opponent. No main effects of the polymorphisms on aggressive behavior were found after controlling for multiple testing. The interactive effects between alcohol and two of the OXTR polymorphisms (rs4564970 and rs1488467) on aggressive behavior were nominally significant and remained significant for the rs4564970 when controlled for multiple tests. To the best of our knowledge, this is the first experimental study suggesting interactive effects of specific genetic variants and alcohol on aggressive behavior in humans.

  8. Variation in the oxytocin receptor gene (OXTR) is associated with differences in moral judgment.

    PubMed

    Bernhard, Regan M; Chaponis, Jonathan; Siburian, Richie; Gallagher, Patience; Ransohoff, Katherine; Wikler, Daniel; Perlis, Roy H; Greene, Joshua D

    2016-12-01

    Moral judgments are produced through the coordinated interaction of multiple neural systems, each of which relies on a characteristic set of neurotransmitters. Genes that produce or regulate these neurotransmitters may have distinctive influences on moral judgment. Two studies examined potential genetic influences on moral judgment using dilemmas that reliably elicit competing automatic and controlled responses, generated by dissociable neural systems. Study 1 (N = 228) examined 49 common variants (SNPs) within 10 candidate genes and identified a nominal association between a polymorphism (rs237889) of the oxytocin receptor gene (OXTR) and variation in deontological vs utilitarian moral judgment (that is, judgments favoring individual rights vs the greater good). An association was likewise observed for rs1042615 of the arginine vasopressin receptor gene (AVPR1A). Study 2 (N = 322) aimed to replicate these findings using the aforementioned dilemmas as well as a new set of structurally similar medical dilemmas. Study 2 failed to replicate the association with AVPR1A, but replicated the OXTR finding using both the original and new dilemmas. Together, these findings suggest that moral judgment is influenced by variation in the oxytocin receptor gene and, more generally, that single genetic polymorphisms can have a detectable effect on complex decision processes.

  9. Variation in the oxytocin receptor gene (OXTR) is associated with differences in moral judgment

    PubMed Central

    Chaponis, Jonathan; Siburian, Richie; Gallagher, Patience; Ransohoff, Katherine; Wikler, Daniel; Perlis, Roy H.; Greene, Joshua D.

    2016-01-01

    Moral judgments are produced through the coordinated interaction of multiple neural systems, each of which relies on a characteristic set of neurotransmitters. Genes that produce or regulate these neurotransmitters may have distinctive influences on moral judgment. Two studies examined potential genetic influences on moral judgment using dilemmas that reliably elicit competing automatic and controlled responses, generated by dissociable neural systems. Study 1 (N = 228) examined 49 common variants (SNPs) within 10 candidate genes and identified a nominal association between a polymorphism (rs237889) of the oxytocin receptor gene (OXTR) and variation in deontological vs utilitarian moral judgment (that is, judgments favoring individual rights vs the greater good). An association was likewise observed for rs1042615 of the arginine vasopressin receptor gene (AVPR1A). Study 2 (N = 322) aimed to replicate these findings using the aforementioned dilemmas as well as a new set of structurally similar medical dilemmas. Study 2 failed to replicate the association with AVPR1A, but replicated the OXTR finding using both the original and new dilemmas. Together, these findings suggest that moral judgment is influenced by variation in the oxytocin receptor gene and, more generally, that single genetic polymorphisms can have a detectable effect on complex decision processes. PMID:27497314

  10. Environmental stress, oxytocin receptor gene (OXTR) polymorphism, and mental health following collective stress.

    PubMed

    Lucas-Thompson, Rachel G; Holman, E Alison

    2013-04-01

    We examined whether the oxytocin receptor gene (OXTR) single nucleotide polymorphism (SNP) rs53576 genotype buffers the combined impact of negative social environments (e.g., interpersonal conflict/constraint) and economic stress on post-traumatic stress (PTS) symptoms and impaired daily functioning following collective stress (September 11th terrorist attacks). Saliva was collected by mail and used to genotype 704 respondents. Participants completed Web-based assessments of pre-9/11 mental health, acute stress 9-23 days after 9/11, the quality of social environments 1 year post-9/11, economic stress 18 months post-9/11, and PTS symptoms and impaired functioning 2 and 3 years post-9/11. Interactions between negative social environments and economic stress were examined separately based on OXTR rs53576 genotype (GG vs. any A allele). For individuals with an A allele, a negative social environment significantly increased PTS symptoms without regard to the level of economic stress experienced. However, for respondents with a GG genotype, negative social environments predicted elevated PTS symptoms only for those also experiencing high economic stress. Gender moderated associations between negative social environments, economic stress, and impaired functioning. The functioning of females was most affected by negative social environments regardless of genotype and economic stress, whereas the functioning of males was differentially susceptible to economic stress depending on OXTR genotype and negative social environments. These findings suggest that it is important to consider the combined impact of gender and ongoing stress in different domains as moderators of genetic vulnerability following collective stress.

  11. Environmental risk, Oxytocin Receptor Gene (OXTR) methylation and youth callous-unemotional traits: A 13-year longitudinal study

    PubMed Central

    Cecil, Charlotte AM; Lysenko, Laura J.; Jaffee, Sara R.; Pingault, Jean-Baptiste; Smith, Rebecca G.; Relton, Caroline L.; Woodward, Geoffrey; McArdle, Wendy; Mill, Jonathan; Barker, Edward D.

    2014-01-01

    Youth with high callous-unemotional traits (CU) are at risk for early-onset and persistent conduct problems. Research suggests that there may be different developmental pathways to CU (genetic/constitutional vs environmental), and that the absence or presence of co-occurring internalizing problems is a key marker. However, it is unclear whether such a distinction is valid. Intermediate phenotypes such as DNA methylation, an epigenetic modification regulating gene expression, may help to clarify aetiological pathways. This is the first study to examine prospective inter-relationships between environmental risk (prenatal/postnatal) and DNA methylation (birth, age 7, age 9) in the prediction of CU (age 13), for youth low vs. high in internalizing problems. We focused on DNA methylation in the vicinity of the oxytocin receptor (OXTR) gene as it has been previously implicated in CU. Participants were 84 youth with early-onset and persistent conduct problems drawn from the Avon Longitudinal Study of Parents and Children. For youth with low internalizing problems (46%), we found that: (i) OXTR methylation at birth associated with higher CU (age 13) as well as decreased experience of victimization during childhood (birth – age 9), (ii) higher prenatal parental risks (maternal psychopathology, criminal behaviors, substance use) associated with higher OXTR methylation at birth, and (iii) OXTR methylation levels were more stable across time (birth – age 9). In contrast, for youth with high internalizing problems, CU was associated with prenatal risks of an interpersonal nature (i.e., intimate partner violence, family conflict) but not OXTR methylation. Findings support the existence of distinct developmental pathways to CU. PMID:25199917

  12. Association of Oxytocin Receptor Gene (OXTR) rs53576 Polymorphism with Sociality: A Meta-Analysis

    PubMed Central

    Li, Jingguang; Zhao, Yajun; Li, Rena; Broster, Lucas S.; Zhou, Chenglin; Yang, Suyong

    2015-01-01

    A common variant in the oxytocin receptor gene (OXTR), rs53576, has been broadly linked to socially related personality traits and behaviors. However, the pattern of published results is inconsistent. Here, we performed a meta-analysis to comprehensively evaluate the association. The literature was searched for relevant studies and effect sizes between individuals homozygous for the G allele (GG) and individuals with A allele carriers (AA/AG). Specifically, two indices of sociality were evaluated independently: i) general sociality (24 samples, n = 4955), i.e., how an individual responds to other people in general; and ii) close relationships (15 samples, n = 5262), i.e., how an individual responds to individuals with closed connections (parent-child or romantic relationship). We found positive association between the rs53576 polymorphism and general sociality (Cohen’s d = 0.11, p = .02); G allele homozygotes had higher general sociality than the A allele carriers. However, the meta-analyses did not detect significant genetic association between rs53576 and close relationships (Cohen’s d = 0.01, p = .64). In conclusion, genetic variation in the rs53576 influences general sociality, which further implies that it is worthy to systematically examine whether the rs53576 is a valid genetic marker for socially related psychiatric disorders. PMID:26121678

  13. Religion priming and an oxytocin receptor gene (OXTR) polymorphism interact to affect self-control in a social context.

    PubMed

    Sasaki, Joni Y; Mojaverian, Taraneh; Kim, Heejung S

    2015-02-01

    Using a genetic moderation approach, this study examines how an experimental prime of religion impacts self-control in a social context, and whether this effect differs depending on the genotype of an oxytocin receptor gene (OXTR) polymorphism (rs53576). People with different genotypes of OXTR seem to have different genetic orientations toward sociality, which may have consequences for the way they respond to religious cues in the environment. In order to determine whether the influence of religion priming on self-control is socially motivated, we examine whether this effect is stronger for people who have OXTR genotypes that should be linked to greater rather than less social sensitivity (i.e., GG vs. AA/AG genotypes). The results showed that experimentally priming religion increased self-control behaviors for people with GG genotypes more so than people with AA/AG genotypes. Furthermore, this Gene × Religion interaction emerged in a social context, when people were interacting face to face with another person. This research integrates genetic moderation and social psychological approaches to address a novel question about religion's influence on self-control behavior, which has implications for coping with distress and psychopathology. These findings also highlight the importance of the social context for understanding genetic moderation of psychological effects.

  14. Congenital prosopagnosia is associated with a genetic variation in the oxytocin receptor (OXTR) gene: An exploratory study.

    PubMed

    Cattaneo, Zaira; Daini, Roberta; Malaspina, Manuela; Manai, Federico; Lillo, Mariarita; Fermi, Valentina; Schiavi, Susanna; Suchan, Boris; Comincini, Sergio

    2016-12-17

    Face-recognition deficits, referred to with the term prosopagnosia (i.e., face blindness), may manifest during development in the absence of any brain injury (from here the term congenital prosopagnosia, CP). It has been estimated that approximately 2.5% of the population is affected by face-processing deficits not depending on brain lesions, and varying a lot in severity. The genetic bases of this disorder are not known. In this study we tested for genetic association between single-nucleotide polymorphisms (SNPs) in the oxytocin receptor gene (OXTR) and CP in a restricted cohort of Italian participants. We found evidence of an association between the common genetic variants rs53576 and rs2254298 OXTR SNPs and prosopagnosia. This association was also found when including an additional group of German individuals classified as prosopagnosic in the analysis. Our preliminary data provide initial support for the involvement of genetic variants of OXTR in a relevant cognitive impairment, whose genetic bases are still largely unexplored.

  15. Rigorous tests of gene-environment interactions in a lab study of the oxytocin receptor gene (OXTR), alcohol exposure, and aggression.

    PubMed

    LoParo, Devon; Johansson, Ada; Walum, Hasse; Westberg, Lars; Santtila, Pekka; Waldman, Irwin

    2016-07-01

    Naturalistic studies of gene-environment interactions (G X E) have been plagued by several limitations, including difficulty isolating specific environmental risk factors from other correlated aspects of the environment, gene-environment correlation (rGE ), and the use of a single genetic variant to represent the influence of a gene. We present results from 235 Finnish young men in two lab studies of aggression and alcohol challenge that attempt to redress these limitations of the extant G X E literature. Specifically, we use a latent variable modeling approach in an attempt to more fully account for genetic variation across the oxytocin receptor gene (OXTR) and to robustly test its main effects on aggression and its interaction with alcohol exposure. We also modeled aggression as a latent variable comprising various indices, including the average and maximum levels of aggression, the earliest trial on which aggression was expressed, and the proportion of trials on which the minimum and maximum levels of aggression were expressed. The best fitting model for the genetic variation across OXTR included six factors derived from an exploratory factor analysis, roughly corresponding to six haplotype blocks. Aggression levels were higher on trials in which participants were administered alcohol, won, or were provoked. There was a significant main effect of OXTR on aggression across studies after controlling for covariates. The interaction of OXTR and alcohol was also significant across studies, such that OXTR had stronger effects on aggression in the alcohol administration condition. © 2015 Wiley Periodicals, Inc.

  16. Associations between oxytocin receptor gene (OXTR) polymorphisms and self-reported aggressive behavior and anger: Interactions with alcohol consumption.

    PubMed

    Johansson, Ada; Westberg, Lars; Sandnabba, Kenneth; Jern, Patrick; Salo, Benny; Santtila, Pekka

    2012-09-01

    Oxytocin has been implicated in the regulation of social as well as aggressive behaviors, and in a recent study we found that the effect of alcohol on aggressive behavior was moderated by the individual's genotype on an oxytocin receptor gene (OXTR) polymorphism (Johansson et al., 2012). In this study we wanted to deepen and expand the analysis by exploring associations between three (rs1488467, rs4564970, rs1042778) OXTR polymorphisms and aggressive behavior, trait anger as well as anger control in a population-based sample of Finnish men and women (N=3577) aged between 18 and 49 years (M=26.45 years, SD=5.02). A specific aim was to investigate if the polymorphisms would show interactive effects with alcohol consumption on aggressive behavior and trait anger, as well as to explore whether these polymorphisms affect differences in anger control between self-reported sober and intoxicated states. The results showed no main effects of the polymorphisms, however, three interactions between the polymorphisms and alcohol consumption were found. The effect of alcohol consumption on aggressive behavior was moderated by the genotype of the individual on the rs4564970 polymorphism, in line with previous results (Johansson et al., 2012). For trait anger, both the rs1488467 and the rs4564970 polymorphisms interacted with alcohol consumption. It appears that the region of the OXTR gene including both the rs4564970 and the rs1488467 polymorphisms may be involved in the regulation of the relationship between alcohol and aggressive behavior as well as between alcohol and the propensity to react to situations with elevated levels of anger.

  17. Preliminary evidence for the interaction of the oxytocin receptor gene (oxtr) and face processing in differentiating prenatal smoking patterns.

    PubMed

    Massey, Suena H; Estabrook, Ryne; O'Brien, T Caitlin; Pine, Daniel S; Burns, James L; Jacob, Suma; Cook, Edwin H; Wakschlag, Lauren S

    2015-01-01

    Prenatal smoking cessation has been described as an empathic action "for the baby," but this has not been empirically demonstrated. We capitalized on a genetically-characterized extant dataset with outstanding measurement of prenatal smoking patterns and maternal face processing data (as an indicator of empathy) to test this hypothesis, and explore how empathy and smoking patterns may be moderated by a genetic substrate of empathy, the oxytocin receptor gene (OXTR). Participants were 143 Caucasian women from the East Boston family study with repeated prospective reports of smoking level, adjusted based on repeated cotinine bioassays. Salivary DNA and face processing (Diagnostic Analysis of Nonverbal Accuracy-2) were assessed 14 years later at an adolescent follow-up of offspring. Two-thirds of participants reported smoking prior to pregnancy recognition. Of these, 21% quit during pregnancy; 56% reduced smoking, and 22% smoked persistently at the same level. A significant interaction between face processing and OXTR variants previously associated with increased sensitivity to social context, rs53576GG and rs2254298A, was found (β = -.181; p = .015); greater ability to identify distress in others was associated with lower levels of smoking during pregnancy for rs53576(GG)/rs2254298(A) individuals (p = .013), but not for other genotypes (p = .892). Testing this "empathy hypothesis of prenatal smoking cessation" in larger studies designed to examine this question can elucidate whether interventions to enhance empathy can improve prenatal smoking cessation rates.

  18. Preliminary Evidence for the Interaction of the Oxytocin Receptor Gene (OXTR) and Face Processing in Differentiating Prenatal Smoking Patterns

    PubMed Central

    Massey, Suena H.; Estabrook, Ryne; O’Brien, T. Caitlin; Pine, Daniel S.; Burns, James L.; Jacob, Suma; Cook, Edwin H.; Wakschlag, Lauren S.

    2014-01-01

    Prenatal smoking cessation has been described as an empathic action “for the baby,” but this has not been empirically demonstrated. We capitalized on a genetically-characterized extant dataset with outstanding measurement of prenatal smoking patterns and maternal face processing data (as an indicator of empathy) to test this hypothesis, and explore how empathy and smoking patterns may be moderated by a genetic substrate of empathy, the oxytocin receptor gene (OXTR). Participants were 143 Caucasian women from the East Boston Family Study with repeated prospective reports of smoking level, adjusted based on repeated cotinine bioassays. Salivary DNA and face processing (Diagnostic Analysis of Nonverbal Accuracy-2) were assessed 14 years later at an adolescent follow-up of offspring. Two-thirds of participants reported smoking prior to pregnancy recognition. Of these, 21% quit during pregnancy; 56% reduced smoking, and 22% smoked persistently at the same level. A significant interaction between face processing and OXTR variants previously associated with increased sensitivity to social context, rs53576GG and rs2254298A, was found (β = -.181; p = .015); greater ability to identify distress in others was associated with lower levels of smoking during pregnancy for rs53576(GG)/rs2254298(A) individuals (p = .013), but not for other genotypes (p = .892). Testing this “empathy hypothesis of prenatal smoking cessation” in larger studies designed to examine this question can elucidate whether interventions to enhance empathy can improve prenatal smoking cessation rates. PMID:25450139

  19. Evidence for the involvement of genetic variation in the oxytocin receptor gene (OXTR) in the etiology of autistic disorders on high-functioning level.

    PubMed

    Wermter, Anne-Kathrin; Kamp-Becker, Inge; Hesse, Philipp; Schulte-Körne, Gerd; Strauch, Konstantin; Remschmidt, Helmut

    2010-03-05

    An increasing number of animal studies advert to a substantial role of the neuropeptide oxytocin in the regulation of social attachment and affiliation. Furthermore, animal studies showed anxiety and stress-reduced effects of oxytocin. First human studies confirm these findings in animal studies and implicate a crucial role of oxytocin in human social attachment behavior and in social interactions. Thus, the oxytocin system might be involved in the impairment of social interaction and attachment in autism spectrum disorders (ASD). The human oxytocin receptor gene (OXTR) represents a plausible candidate gene for the etiology of ASD. To analyze whether genetic variants in the OXTR gene are associated with ASD we performed family-based single-marker and haplotype association analyses with 22 single nucleotide polymorphisms (SNPs) in the OXTR and its 5' region in 100 families with autistic disorders on high-functioning level (Asperger syndrome (AS), high-functioning autism (HFA), and atypical autism (AA)). Single-marker and haplotype association analyses revealed nominally significant associations of one single SNP and one haplotype with autism, respectively. Furthermore, employing a "reverse phenotyping" approach, patients carrying the haplotype associated with autism showed nominally significant impairments in comparison to noncarriers of the haplotype in items of the Autism Diagnostic Interview-Revised algorithm describing aspects of social interaction and communication. In conclusion, our results implicate that genetic variation in the OXTR gene might be relevant in the etiology of autism on high-functioning level.

  20. A common oxytocin receptor gene (OXTR) polymorphism modulates intranasal oxytocin effects on the neural response to social cooperation in humans

    PubMed Central

    Feng, Chunliang; Lori, Adriana; Waldman, Irwin D.; Binder, Elisabeth B.; Haroon, Ebrahim; Rilling, James K.

    2015-01-01

    Intranasal oxytocin (OT) can modulate social-emotional functioning and related brain activity in humans. Consequently, OT has been discussed as a potential treatment for psychiatric disorders involving social behavioral deficits. However, OT effects are often heterogeneous across individuals. Here we explore individual differences in OT effects on the neural response to social cooperation as a function of the rs53576 polymorphism of the oxytocin receptor gene (OXTR). Previously, we conducted a double-blind, placebo-controlled study in which healthy men and women were randomized to treatment with intranasal OT or placebo. Afterwards, they were imaged with fMRI while playing an iterated Prisoner’s Dilemma Game with same-sex partners. Within the left ventral caudate nucleus, intranasal OT treatment increased activation to reciprocated cooperation in men, but tended to decrease activation in women. Here, we show that these sex differences in OT effects are specific to individuals with the rs53576 GG genotype, and are not found for other genotypes (rs53576 AA/AG). Thus, OT may increase the reward or salience of positive social interactions for male GG homozygotes, while decreasing those processes for female GG homozygotes. These results suggest that rs53576 genotype is an important variable to consider in future investigations of the clinical efficacy of intranasal OT treatment. PMID:26178189

  1. A common oxytocin receptor gene (OXTR) polymorphism modulates intranasal oxytocin effects on the neural response to social cooperation in humans.

    PubMed

    Feng, C; Lori, A; Waldman, I D; Binder, E B; Haroon, E; Rilling, J K

    2015-09-01

    Intranasal oxytocin (OT) can modulate social-emotional functioning and related brain activity in humans. Consequently, OT has been discussed as a potential treatment for psychiatric disorders involving social behavioral deficits. However, OT effects are often heterogeneous across individuals. Here we explore individual differences in OT effects on the neural response to social cooperation as a function of the rs53576 polymorphism of the oxytocin receptor gene (OXTR). Previously, we conducted a double-blind, placebo-controlled study in which healthy men and women were randomized to treatment with intranasal OT or placebo. Afterwards, they were imaged with functional magnetic resonance imaging while playing an iterated Prisoner's Dilemma Game with same-sex partners. Within the left ventral caudate nucleus, intranasal OT treatment increased activation to reciprocated cooperation in men, but tended to decrease activation in women. Here, we show that these sex differences in OT effects are specific to individuals with the rs53576 GG genotype, and are not found for other genotypes (rs53576 AA/AG). Thus, OT may increase the reward or salience of positive social interactions for male GG homozygotes, while decreasing those processes for female GG homozygotes. These results suggest that rs53576 genotype is an important variable to consider in future investigations of the clinical efficacy of intranasal OT treatment.

  2. Genetic imaging of the association of oxytocin receptor gene (OXTR) polymorphisms with positive maternal parenting

    PubMed Central

    Michalska, Kalina J.; Decety, Jean; Liu, Chunyu; Chen, Qi; Martz, Meghan E.; Jacob, Suma; Hipwell, Alison E.; Lee, Steve S.; Chronis-Tuscano, Andrea; Waldman, Irwin D.; Lahey, Benjamin B.

    2013-01-01

    Background: Well-validated models of maternal behavior in small-brain mammals posit a central role of oxytocin in parenting, by reducing stress and enhancing the reward value of social interactions with offspring. In contrast, human studies are only beginning to gain insights into how oxytocin modulates maternal behavior and affiliation. Methods: To explore associations between oxytocin receptor genes and maternal parenting behavior in humans, we conducted a genetic imaging study of women selected to exhibit a wide range of observed parenting when their children were 4–6 years old. Results: In response to child stimuli during functional magnetic resonance imaging (fMRI), hemodynamic responses in brain regions that mediate affect, reward, and social behavior were significantly correlated with observed positive parenting. Furthermore, single nucleotide polymorphisms (SNPs) (rs53576 and rs1042778) in the gene encoding the oxytocin receptor were significantly associated with both positive parenting and hemodynamic responses to child stimuli in orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and hippocampus. Conclusions: These findings contribute to the emerging literature on the role of oxytocin in human social behavior and support the feasibility of tracing biological pathways from genes to neural regions to positive maternal parenting behaviors in humans using genetic imaging methods. PMID:24550797

  3. DNA methylation and single nucleotide variants in the brain-derived neurotrophic factor (BDNF) and oxytocin receptor (OXTR) genes are associated with anxiety/depression in older women

    PubMed Central

    Chagnon, Yvon C.; Potvin, Olivier; Hudon, Carol; Préville, Michel

    2015-01-01

    Background: Environmental effects and personal experiences could be expressed in individuals through epigenetic non-structural changes such as DNA methylation. This methylation could up- regulate or down-regulate corresponding gene expressions and modify related phenotypes. DNA methylation increases with aging and could be related to the late expression of some forms of mental disease. The objective of this study was to evaluate the association between anxiety disorders and/or depression in older women and DNA methylation for four genes related to anxiety or depression. Methods: Women aged 65 and older with (n = 19) or without (n = 24) anxiety disorders and/or major depressive episode (DSM-IV), were recruited. DNA methylation and single nucleotide variant (SNV) were evaluated from saliva, respectively by pyrosequencing and by PCR, for the following genes: brain-derived neurotrophic factor (BDNF; rs6265), oxytocin receptor (OXTR; rs53576), serotonin transporter (SLC6A4; rs25531), and apolipoprotein E (APOE; rs429358 and rs7412). Results: A greater BDNF DNA methylation was observed in subjects with anxiety/depression compared to control group subjects (Mean: 2.92 SD ± 0.74 vs. 2.34 ± 0.42; p= 0.0026). This difference was more pronounced in subjects carrying the BDNF rs6265 CT genotype (2.99 ± 0.41 vs. 2.27 ± 0.26; p= 0.0006) than those carrying the CC genotype (p= 0.0332); no subjects with the TT genotype were observed. For OXTR, a greater DNA methylation was observed in subjects with anxiety/depression, but only for those carrying the AA genotype of the OXTR rs53576 SNV, more particularly at one out of the seven CpGs studied (7.01 ± 0.94 vs. 4.44 ± 1.11; p= 0.0063). No significant differences were observed for APOE and SLC6A4. Conclusion: These results suggest that DNA methylation in interaction with SNV variations in BDNF and OXTR, are associated with the occurrence of anxiety/depression in older women. PMID:26175754

  4. Common polymorphism in the oxytocin receptor gene (OXTR) is associated with human social recognition skills

    PubMed Central

    Skuse, David H.; Lori, Adriana; Cubells, Joseph F.; Lee, Irene; Conneely, Karen N.; Puura, Kaija; Lehtimäki, Terho; Binder, Elisabeth B.; Young, Larry J.

    2014-01-01

    The neuropeptides oxytocin and vasopressin are evolutionarily conserved regulators of social perception and behavior. Evidence is building that they are critically involved in the development of social recognition skills within rodent species, primates, and humans. We investigated whether common polymorphisms in the genes encoding the oxytocin and vasopressin 1a receptors influence social memory for faces. Our sample comprised 198 families, from the United Kingdom and Finland, in whom a single child had been diagnosed with high-functioning autism. Previous research has shown that impaired social perception, characteristic of autism, extends to the first-degree relatives of autistic individuals, implying heritable risk. Assessments of face recognition memory, discrimination of facial emotions, and direction of gaze detection were standardized for age (7–60 y) and sex. A common SNP in the oxytocin receptor (rs237887) was strongly associated with recognition memory in combined probands, parents, and siblings after correction for multiple comparisons. Homozygotes for the ancestral A allele had impairments in the range −0.6 to −1.15 SD scores, irrespective of their diagnostic status. Our findings imply that a critical role for the oxytocin system in social recognition has been conserved across perceptual boundaries through evolution, from olfaction in rodents to visual memory in humans. PMID:24367110

  5. Lack of Association between Oxytocin Receptor (OXTR) Gene Polymorphisms and Alexithymia: Evidence from Patients with Obsessive-Compulsive Disorder.

    PubMed

    Koh, Min Jung; Kim, Wonji; Kang, Jee In; Namkoong, Kee; Kim, Se Joo

    2015-01-01

    Oxytocin receptor gene single nucleotide polymorphisms have been associated with structural and functional alterations in brain regions, which involve social-emotional processing. Therefore, oxytocin receptor gene polymorphisms may contribute to individual differences in alexithymia, which is considered to be a dysfunction of emotional processing. The aim of this study was to evaluate the association between oxytocin receptor gene single nucleotide polymorphisms or haplotypes and alexithymia in patients with obsessive-compulsive disorder. We recruited 355 patients with obsessive-compulsive disorder (234 men, 121 women). Alexithymia was measured by using the Toronto Alexithymia Scale. We performed single-marker and haplotype association analyses with eight single nucleotide polymorphisms (rs237885, rs237887, rs2268490, rs4686301, rs2254298, rs13316193, rs53576, and rs2268498) in the oxytocin receptor gene. There were no significant associations between any of the eight single nucleotide polymorphism of the oxytocin receptor gene and alexithymia. In addition, a six-locus haplotype block (rs237885-rs237887-rs2268490-rs4686301-rs2254298-rs13316193) was not significantly associated with alexithymia. These findings suggest that genetic variations in the oxytocin receptor gene may not explain a significant part of alexithymia in patients with obsessive-compulsive disorder.

  6. Childhood maternal care is associated with DNA methylation of the genes for brain-derived neurotrophic factor (BDNF) and oxytocin receptor (OXTR) in peripheral blood cells in adult men and women.

    PubMed

    Unternaehrer, Eva; Meyer, Andrea Hans; Burkhardt, Susan C A; Dempster, Emma; Staehli, Simon; Theill, Nathan; Lieb, Roselind; Meinlschmidt, Gunther

    2015-01-01

    In adults, reporting low and high maternal care in childhood, we compared DNA methylation in two stress-associated genes (two target sequences in the oxytocin receptor gene, OXTR; one in the brain-derived neurotrophic factor gene, BDNF) in peripheral whole blood, in a cross-sectional study (University of Basel, Switzerland) during 2007-2008. We recruited 89 participants scoring < 27 (n = 47, 36 women) or > 33 (n = 42, 35 women) on the maternal care subscale of the Parental Bonding Instrument (PBI) at a previous assessment of a larger group (N = 709, range PBI maternal care = 0-36, age range = 19-66 years; median 24 years). 85 participants gave blood for DNA methylation analyses (Sequenom(R) EpiTYPER, San Diego, CA) and cell count (Sysmex PocH-100i™, Kobe, Japan). Mixed model statistical analysis showed greater DNA methylation in the low versus high maternal care group, in the BDNF target sequence [Likelihood-Ratio (1) = 4.47; p = 0.035] and in one OXTR target sequence Likelihood-Ratio (1) = 4.33; p = 0.037], but not the second OXTR target sequence [Likelihood-Ratio (1) < 0.001; p = 0.995). Mediation analyses indicated that differential blood cell count did not explain associations between low maternal care and BDNF (estimate = -0.005, 95% CI = -0.025 to 0.015; p = 0.626) or OXTR DNA methylation (estimate = -0.015, 95% CI = -0.038 to 0.008; p = 0.192). Hence, low maternal care in childhood was associated with greater DNA methylation in an OXTR and a BDNF target sequence in blood cells in adulthood. Although the study has limitations (cross-sectional, a wide age range, only three target sequences in two genes studied, small effects, uncertain relevance of changes in blood cells to gene methylation in brain), the findings may indicate components of the epiphenotype from early life stress.

  7. Does the oxytocin receptor (OXTR) polymorphism (rs2254298) confer 'vulnerability' for psychopathology or 'differential susceptibility'? Insights from evolution.

    PubMed

    Brüne, Martin

    2012-04-17

    The diathesis-stress model of psychiatric conditions has recently been challenged by the view that it might be more accurate to speak of 'differential susceptibility' or 'plasticity' genes, rather than one-sidedly focusing on individual vulnerability. That is, the same allelic variation that predisposes to a psychiatric disorder if associated with (developmentally early) environmental adversity may lead to a better-than-average functional outcome in the same domain under thriving (or favourable) environmental conditions. Studies of polymorphic variations of the serotonin transporter gene, the monoamino-oxidase-inhibitor A coding gene or the dopamine D4 receptor gene indicate that the early environment plays a crucial role in the development of favourable versus unfavourable outcomes. Current evidence is limited, however, to establishing a link between genetic variation and behavioural phenotypes. In contrast, little is known about how plasticity may be expressed at the neuroanatomical level as a 'hard-wired' correlate of observable behaviour. The present review article seeks to further strengthen the argument in favour of the differential susceptibility theory by incorporating findings from behavioural and neuroanatomical studies in relation to genetic variation of the oxytocin receptor gene. It is suggested that polymorphic variation at the oxytocin receptor gene (rs2254298) is associated with sociability, amygdala volume and differential risk for psychiatric conditions including autism, depression and anxiety disorder, depending on the quality of early environmental experiences. Seeing genetic variation at the core of developmental plasticity can explain, in contrast to the diathesis-stress perspective, why evolution by natural selection has maintained such 'risk' alleles in the gene pool of a population.

  8. Impairments in the Initiation of Maternal Behavior in Oxytocin Receptor Knockout Mice

    PubMed Central

    Rich, Megan E.; deCárdenas, Emily J.; Lee, Heon-Jin; Caldwell, Heather K.

    2014-01-01

    Oxytocin (Oxt) acting through its single receptor subtype, the Oxtr, is important for the coordination of physiology and behavior associated with parturition and maternal care. Knockout mouse models have been helpful in exploring the contributions of Oxt to maternal behavior, including total body Oxt knockout (Oxt −/−) mice, forebrain conditional Oxtr knockout (Oxtr FB/FB) mice, and total body Oxtr knockout (Oxtr −/−) mice. Since Oxtr −/− mice are unable to lactate, maternal behavior has only been examined in virgin females, or in dams within a few hours of parturition, and there have been no studies that have examined their anxiety-like and depression-like behavior following parturition. To improve our understanding of how the absence of Oxt signaling affects maternal behavior, mood and anxiety, we designed a study using Oxtr −/− mice that separated nursing behavior from other aspects of maternal care, such as licking and grooming by thelectomizing (i.e. removing the nipples) of Oxtr +/+ mice and sham-thelectomizing Oxtr −/− mice, and pairing both genotypes with a wet nurse. We then measured pup abandonment, maternal behavior, and postpartum anxiety-like and depression-like behaviors. We hypothesized that genetic disruption of the Oxtr would impact maternal care, mood and anxiety. Specifically, we predicted that Oxtr −/− dams would have impaired maternal care and increased anxiety-like and depression-like behaviors in the postpartum period. We found that Oxtr −/− dams had significantly higher levels of pup abandonment compared to controls, which is consistent with previous work in Oxtr FB/FB mice. Interestingly, Oxtr −/− dams that initiated maternal care did not differ from wildtype controls in measures of maternal behavior. We also did not find any evidence of altered anxiety-like or depressive-like behavior in the postpartum period of Oxtr −/− dams. Thus, our data suggest that Oxt lowers the threshold for the initiation of

  9. Lessons from the canine Oxtr gene: populations, variants and functional aspects.

    PubMed

    Bence, M; Marx, P; Szantai, E; Kubinyi, E; Ronai, Z; Banlaki, Z

    2017-04-01

    Oxytocin receptor (OXTR) acts as a key behavioral modulator of the central nervous system, affecting social behavior, stress, affiliation and cognitive functions. Variants of the Oxtr gene are known to influence behavior both in animals and humans; however, canine Oxtr polymorphisms are less characterized in terms of possible relevance to function, selection criteria in breeding and domestication. In this report, we provide a detailed characterization of common variants of the canine Oxtr gene. In particular (1) novel polymorphisms were identified by direct sequencing of wolf and dog samples, (2) allelic distributions and pairwise linkage disequilibrium patterns of several canine populations were compared, (3) neighbor joining (NJ) tree based on common single nucleotide polymorphisms (SNPs) was constructed, (4) mRNA expression features were assessed, (5) a novel splice variant was detected and (6) in vitro functional assays were performed. Results indicate marked differences regarding Oxtr variations between purebred dogs of different breeds, free-ranging dog populations, wolf subspecies and golden jackals. This, together with existence of explicitly dog-specific alleles and data obtained from the NJ tree implies that Oxtr could indeed have been a target gene during domestication and selection for human preferred aspects of temperament and social behavior. This assumption is further supported by the present observations on gene expression patterns within the brain and luciferase reporter experiments, providing a molecular level link between certain canine Oxtr polymorphisms and differences in nervous system function and behavior.

  10. Molecular genetic studies of the arginine vasopressin 1a receptor (AVPR1a) and the oxytocin receptor (OXTR) in human behaviour: from autism to altruism with some notes in between.

    PubMed

    Israel, Salomon; Lerer, Elad; Shalev, Idan; Uzefovsky, Florina; Reibold, Mathias; Bachner-Melman, Rachel; Granot, Roni; Bornstein, Gary; Knafo, Ariel; Yirmiya, Nurit; Ebstein, Richard P

    2008-01-01

    Converging evidence from both human and animal studies has highlighted the pervasive role of two neuropeptides, oxytocin (OXT) and arginine vasopressin (AVP), in mammalian social behaviours. Recent molecular genetic studies of the human arginine vasopressin 1a (AVPR1a) and oxytocin (OXTR) receptors have strengthened the evidence regarding the role of these two neuropeptides in a range of normal and pathological behaviours. Significant association between both AVPR1a repeat regions and OXTR single nucleotide polymorphisms (SNPs) with risk for autism has been provisionally shown which was mediated by socialization skills in our study. AVPR1a has also been linked to eating behaviour in both clinical and non-clinical groups, perhaps reflecting the social and ritualistic side of eating behaviour. Evidence also suggests that repeat variations in AVPR1a are associated with two other social domains in Homo sapiens: music and altruism. AVPR1a was associated with dance and musical cognition which we theorize as reflecting the ancient role of this hormone in social interactions executed by vocalization, ritual movement and dyadic (mother-offspring) and group communication. Finally, we have shown that individual differences in allocation of funds in the dictator game, a laboratory game of pure altruism, is predicted by length of the AVPR1a RS3 promoter-region repeat echoing the mechanism of this hormone's action in the vole model of affiliative behaviours and facilitation of positive group interactions. While still in its infancy, the current outlook for molecular genetic investigations of AVP-OXT continues to be fascinating. Future studies should profitably focus on pharmacogenomic and genomic imaging strategies facilitated by the ease and efficacy of manipulating AVP-OXT neurotransmission by intranasal administration. Importantly, physiological measures, behavioural paradigms and brain activation can be informed by considering between-group and also within-group individual

  11. Oxytocin receptor knockout mice display deficits in the expression of autism-related behaviors.

    PubMed

    Pobbe, Roger L H; Pearson, Brandon L; Defensor, Erwin B; Bolivar, Valerie J; Young, W Scott; Lee, Heon-Jin; Blanchard, D Caroline; Blanchard, Robert J

    2012-03-01

    A wealth of studies has implicated oxytocin (Oxt) and its receptors (Oxtr) in the mediation of social behaviors and social memory in rodents. It has been suggested that failures in this system contribute to deficits in social interaction that characterize autism spectrum disorders (ASD). In the current analyses, we investigated the expression of autism-related behaviors in mice that lack the ability to synthesize the oxytocin receptor itself, Oxtr knockout (KO) mice, as compared to their wild-type (WT) littermates. In the visible burrow system, Oxtr KO mice showed robust reductions in frontal approach, huddling, allo-grooming, and flight, with more time spent alone, and in self-grooming, as compared to WT. These results were corroborated in the three-chambered test: unlike WT, Oxtr KO mice failed to spend more time in the side of the test box containing an unfamiliar CD-1 mouse. In the social proximity test, Oxtr KO mice showed clear reductions in nose to nose and anogenital sniff behaviors oriented to an unfamiliar C57BL/6J (B6) mouse. In addition, our study revealed no differences between Oxtr WT and KO genotypes in the occurrence of motor and cognitive stereotyped behaviors. A significant genotype effect was found in the scent marking analysis, with Oxtr KO mice showing a decreased number of scent marks, as compared to WT. Overall, the present data indicate that the profile for Oxtr KO mice, including consistent social deficits, and reduced levels of communication, models multiple components of the ASD phenotype. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

  12. Revisiting the impact of OXTR rs53576 on empathy: A population-based study and a meta-analysis.

    PubMed

    Gong, Pingyuan; Fan, Huiyong; Liu, Jinting; Yang, Xing; Zhang, Kejin; Zhou, Xiaolin

    2017-03-09

    Oxytocin in the brain is related to empathy, which refers to the ability to understand and share others' internal states or responses. Previous studies have investigated the impact of OXTR rs53576, the most intensively examined polymorphism in the oxytocin receptor (OXTR) gene, on individual differences in empathy. However, these studies produced inconsistent results. In the current study, we reexamined the association of OXTR rs53576 with empathy in a relatively large population (N=1830) and also evaluated the association by a comprehensive meta-analysis (N=6631, 13 independent samples). The replication study indicated that OXTR rs53576 was indeed associated with individual differences in empathy. Individuals with a greater number of G alleles showed better empathic ability, particularly in fantasizing other's feelings and actions. The meta-analysis not only confirmed this association, but also indicated that the impact of this polymorphism was significant in both Europeans and Asians. These findings provide convincing evidence for the impact of OXTR rs53576 on empathy, highlighting the importance of OXTR gene in individuals' social cognition.

  13. Family environment and adult resilience: contributions of positive parenting and the oxytocin receptor gene

    PubMed Central

    Bradley, Bekh; Davis, Telsie A.; Wingo, Aliza P.; Mercer, Kristina B.; Ressler, Kerry J.

    2013-01-01

    Background Abundant research shows that childhood adversity increases the risk for adult psychopathology while research on influences of positive family environment on risk for psychopathology is limited. Similarly, a growing body of research examines genetic and gene by environment predictors of psychopathology, yet such research on predictors of resilience is sparse. Objectives We examined the role of positive factors in childhood family environment (CFE) and the OXTR rs53576 genotype in predicting levels of adult resilient coping and positive affect. We also examined whether the relationship between positive factors in the CFEs and adult resilient coping and positive affect varied across OXTR rs53576 genotype. Methods We gathered self-report data on childhood environment, trauma history, and adult resilience and positive affect in a sample of 971 African American adults. Results We found that positive CFE was positively associated with higher levels of resilient coping and positive affect in adulthood after controlling for childhood maltreatment, other trauma, and symptoms of posttraumatic stress disorder. We did not find a direct effect of OXTR 53576 on a combined resilient coping/positive-affect-dependent variable, but we did find an interaction of OXTR rs53576 with family environment. Conclusions Our data suggest that even in the face of adversity, positive aspects of the family environment may contribute to resilience. These results highlight the importance of considering protective developmental experiences and the interaction of such experiences with genetic variants in risk and resilience research. PMID:24058725

  14. The oxytocin receptor gene (OXTR) localizes to human chromosome 3p25 by fluorescence in situ hybridization and PCR analysis of somatic cell hybrids

    SciTech Connect

    Simmons, C.F. Jr.; Clancy, T.E.; Quan, R.

    1995-04-10

    The human oxytocin receptor regulates parturition and myometrial contractility, breast milk let-down, and reproductive behaviors in the mammalian central nervous system. Kimura et al. recently identified a human oxytocin receptor cDNA by means of expression cloning from a human myometrial cDNA library. To elucidate further the molecular mechanisms that regulate oxytocin receptor gene expression and to define the expected Mendelian inheritance of possible human disease states, we must determine the number of genes, their localization, and their organization and structure. We summarize below our data indicating that the human oxytocin receptor gene is localized to 3p25 and exists as a single copy in the haploid genome. 9 refs., 2 figs.

  15. Normal maternal behavior, but increased pup mortality, in conditional oxytocin receptor knockout females.

    PubMed

    Macbeth, Abbe H; Stepp, Jennifer E; Lee, Heon-Jin; Young, W Scott; Caldwell, Heather K

    2010-10-01

    Oxytocin (Oxt) and the Oxt receptor (Oxtr) are implicated in the onset of maternal behavior in a variety of species. Recently, we developed two Oxtr knockout lines: a total body knockout (Oxtr-/-) and a conditional Oxtr knockout (OxtrFB/FB) in which the Oxtr is lacking only in regions of the forebrain, allowing knockout females to potentially nurse and care for their biological offspring. In the current study, we assessed maternal behavior of postpartum OxtrFB/FB females toward their own pups and maternal behavior of virgin Oxtr-/- females toward foster pups and compared knockouts of both lines to wildtype (Oxtr+/+) littermates. We found that both Oxtr-/- and OxtrFB/FB females appear to have largely normal maternal behaviors. However, with first litters, approximately 40% of the OxtrFB/FB knockout dams experienced high pup mortality, compared to fewer than 10% of the Oxtr+/+ dams. We then went on to test whether or not this phenotype occurred in subsequent litters or when the dams were exposed to an environmental disturbance. We found that regardless of the degree of external disturbance, OxtrFB/FB females lost more pups on their first and second litters compared to wildtype females. Possible reasons for higher pup mortality in OxtrFB/FB females are discussed.

  16. OXTR polymorphism predicts social relationships through its effects on social temperament.

    PubMed

    Creswell, Kasey G; Wright, Aidan G C; Troxel, Wendy M; Ferrell, Robert E; Flory, Janine D; Manuck, Stephen B

    2015-06-01

    Humans have a fundamental need for strong interpersonal bonds, yet individuals differ appreciably in their degree of social integration. That these differences are also substantially heritable has spurred interest in biological mechanisms underlying the quality and quantity of individuals' social relationships. We propose that polymorphic variation in the oxytocin receptor gene (OXTR) associates with complex social behaviors and social network composition through intermediate effects on negative affectivity and the psychological processing of socially relevant information. We tested a hypothesized social cascade from the molecular level (OXTR variation) to the social environment, through negative affectivity and inhibited sociality, in a sample of 1295 men and women of European American (N = 1081) and African American (N = 214) ancestry. Compared to European Americans having any T allele of rs1042778, individuals homozygous for the alternate G allele reported significantly lower levels of negative affectivity and inhibited sociality, which in turn predicted significantly higher levels of social support and a larger/more diverse social network. Moreover, the effect of rs1042778 variation on social support was fully accounted for by associated differences in negative affectivity and inhibited sociality. Results replicated in the African American sample. Findings suggest that OXTR variation modulates levels of social support via proximal impacts on individual temperament.

  17. Regulation of the macrophage oxytocin receptor in response to inflammation.

    PubMed

    Szeto, Angela; Sun-Suslow, Ni; Mendez, Armando J; Hernandez, Rosa I; Wagner, Klaus V; McCabe, Philip M

    2017-03-01

    It has been demonstrated that the neuropeptide oxytocin (OT) attenuates oxidative stress and inflammation in macrophages. In the current study, we examined the role of inflammation on the expression of the oxytocin receptor (OXTR). We hypothesized that OXTR expression is increased during the inflammation through a nuclear factor-κB (NF-κB)-mediated pathway, thus responding as an acute-phase protein. Inflammation was induced by treating macrophages (human primary, THP-1, and murine) with lipopolysaccharide (LPS) and monitored by expression of IL-6. Expression of OXTR and vasopressin receptors was assessed by qPCR, and OXTR expression was confirmed by immunoblotting. Inflammation upregulated OXTR transcription 10- to 250-fold relative to control in THP-1 and human primary macrophages and increased OXTR protein expression. In contrast, vasopressin receptor-2 mRNA expression was reduced following LPS treatment. Blocking NF-κB activation prevented the increase in OXTR transcription. OT treatment of control cells and LPS-treated cells increased ERK1/2 phosphorylation, demonstrating activation of the OXTR/Gαq/11 signaling pathway. OT activation of OXTR reduced secretion of IL-6 in LPS-activated macrophages. Collectively, these findings suggest that OXTR is an acute-phase protein and that its increased expression is regulated by NF-κB and functions to attenuate cellular inflammatory responses in macrophages.

  18. Type 3 Muscarinic Receptors Contribute to Clearance of Citrobacter rodentium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the alpha 7 nicotinic receptor exerts anti-inflammatory effects on immune cells, the role of muscarinic receptors in mucosal homeostasis, response to enteric pathogens, and modulation of immune cell function is undefined. The contribution of type 3 muscarinic receptor (M3R) to mucosal homeo...

  19. Double Dissociation of the Roles of Metabotropic Glutamate Receptor 5 and Oxytocin Receptor in Discrete Social Behaviors

    PubMed Central

    Mesic, Ivana; Guzman, Yomayra F; Guedea, Anita L; Jovasevic, Vladimir; Corcoran, Kevin A; Leaderbrand, Katherine; Nishimori, Katsuhiko; Contractor, Anis; Radulovic, Jelena

    2015-01-01

    Social interactions in vertebrates are complex phenomena based on affective and cognitive processes. Multiple brain regions and neurotransmitter systems are involved in the expression of social behaviors, but their individual roles in specific aspects of social interactions are not well understood. Here we investigated how Gq-protein-coupled metabotropic glutamate receptor 5 (mGluR5) and oxytocin receptor (Oxtr) affect social affiliation and social memory. We used conditional genetic approaches in which the genes coding for these receptors were knocked out in the lateral septum by infusion of recombinant adeno-associated viral vectors containing Cre recombinase (AAV-Cre). Social behavior was assessed 2 weeks later using a three-chamber paradigm for sociability and preference for social novelty. Septal deletion of mGluR5 abolished sociability while leaving preference for social novelty intact. In contrast, deletion of Oxtr did not affect sociability but significantly impaired preference for social novelty. Nonsocial behaviors or memories, including novel object recognition or fear conditioning, were not affected by these genetic manipulations. Immunohistochemical analyses of the distribution of mGluR5 and Oxtr revealed non-overlapping localization of these receptors within the lateral septum, suggesting that not only different neurotransmitters but also different neuronal types contribute to sociability versus preference for social novelty. Our findings identify highly specialized roles of lateral septal mGluR5 and Oxtr in the the regulation of discrete social behaviors, and suggest that deficits in social interactions, which accompany many mental illnesses, would benefit from comprehensive treatments targeting different components of social functioning. PMID:25824423

  20. Multiple receptors contribute to the behavioral effects of indoleamine hallucinogens.

    PubMed

    Halberstadt, Adam L; Geyer, Mark A

    2011-09-01

    Serotonergic hallucinogens produce profound changes in perception, mood, and cognition. These drugs include phenylalkylamines such as mescaline and 2,5-dimethoxy-4-methylamphetamine (DOM), and indoleamines such as (+)-lysergic acid diethylamide (LSD) and psilocybin. Despite their differences in chemical structure, the two classes of hallucinogens produce remarkably similar subjective effects in humans, and induce cross-tolerance. The phenylalkylamine hallucinogens are selective 5-HT(2) receptor agonists, whereas the indoleamines are relatively non-selective for serotonin (5-HT) receptors. There is extensive evidence, from both animal and human studies, that the characteristic effects of hallucinogens are mediated by interactions with the 5-HT(2A) receptor. Nevertheless, there is also evidence that interactions with other receptor sites contribute to the psychopharmacological and behavioral effects of the indoleamine hallucinogens. This article reviews the evidence demonstrating that the effects of indoleamine hallucinogens in a variety of animal behavioral paradigms are mediated by both 5-HT(2) and non-5-HT(2) receptors.

  1. The Timing of the Excitatory-to-Inhibitory GABA Switch Is Regulated by the Oxytocin Receptor via KCC2

    PubMed Central

    Leonzino, Marianna; Busnelli, Marta; Antonucci, Flavia; Verderio, Claudia; Mazzanti, Michele; Chini, Bice

    2016-01-01

    Summary Oxytocin and its receptor (Oxtr) play a crucial role in the postnatal transition of neuronal GABA neurotransmission from excitatory to inhibitory, a developmental process known as the GABA switch. Using hippocampal neurons from Oxtr-null mice, we show that (1) Oxtr is necessary for the correct timing of the GABA switch by upregulating activity of the chloride cotransporter KCC2, (2) Oxtr, in a very early and narrow time window, directly modulates the functional activity of KCC2 by promoting its phosphorylation and insertion/stabilization at the neuronal surface, and (3) in the absence of Oxtr, electrophysiological alterations are recorded in mature neurons, a finding consistent with a reduced level of KCC2 and increased susceptibility to seizures observed in adult Oxtr-null mice. These data identify KCC2 as a key target of oxytocin in postnatal events that may be linked to pathogenesis of neurodevelopmental disorders. PMID:27052180

  2. Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

    PubMed Central

    Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

    2015-01-01

    The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

  3. Multiple receptors contribute to the behavioral effects of indoleamine hallucinogens

    PubMed Central

    Halberstadt, Adam L.; Geyer, Mark A.

    2011-01-01

    Serotonergic hallucinogens produce profound changes in perception, mood, and cognition. These drugs include phenylalkylamines such as mescaline and 2,5-dimethoxy-4-methylamphetamine (DOM), and indoleamines such as (+)-lysergic acid diethylamide (LSD) and psilocybin. Despite their differences in chemical structure, the two classes of hallucinogens produce remarkably similar subjective effects in humans, and induce cross-tolerance. The phenylalkylamine hallucinogens are selective 5-HT2 receptor agonists, whereas the indoleamines are relatively non-selective for serotonin (5-HT) receptors. There is extensive evidence, from both animal and human studies, that the characteristic effects of hallucinogens are mediated by interactions with the 5-HT2A receptor. Nevertheless, there is also evidence that interactions with other receptor sites contribute to the psychopharmacological and behavioral effects of the indoleamine hallucinogens. This article reviews the evidence demonstrating that the effects of indoleamine hallucinogens in a variety of animal behavioral paradigms are mediated by both 5-HT2 and non-5-HT2 receptors. PMID:21256140

  4. Does the kappa opioid receptor system contribute to pain aversion?

    PubMed

    Cahill, Catherine M; Taylor, Anna M W; Cook, Christopher; Ong, Edmund; Morón, Jose A; Evans, Christopher J

    2014-01-01

    The kappa opioid receptor (KOR) and the endogenous peptide-ligand dynorphin have received significant attention due the involvement in mediating a variety of behavioral and neurophysiological responses, including opposing the rewarding properties of drugs of abuse including opioids. Accumulating evidence indicates this system is involved in regulating states of motivation and emotion. Acute activation of the KOR produces an increase in motivational behavior to escape a threat, however, KOR activation associated with chronic stress leads to the expression of symptoms indicative of mood disorders. It is well accepted that KOR can produce analgesia and is engaged in chronic pain states including neuropathic pain. Spinal studies have revealed KOR-induced analgesia in reversing pain hypersensitivities associated with peripheral nerve injury. While systemic administration of KOR agonists attenuates nociceptive sensory transmission, this effect appears to be a stress-induced effect as anxiolytic agents, including delta opioid receptor agonists, mitigate KOR agonist-induced analgesia. Additionally, while the role of KOR and dynorphin in driving the dysphoric and aversive components of stress and drug withdrawal has been well characterized, how this system mediates the negative emotional states associated with chronic pain is relatively unexplored. This review provides evidence that dynorphin and the KOR system contribute to the negative affective component of pain and that this receptor system likely contributes to the high comorbidity of mood disorders associated with chronic neuropathic pain.

  5. Does the kappa opioid receptor system contribute to pain aversion?

    PubMed Central

    Cahill, Catherine M.; Taylor, Anna M. W.; Cook, Christopher; Ong, Edmund; Morón, Jose A.; Evans, Christopher J.

    2014-01-01

    The kappa opioid receptor (KOR) and the endogenous peptide-ligand dynorphin have received significant attention due the involvement in mediating a variety of behavioral and neurophysiological responses, including opposing the rewarding properties of drugs of abuse including opioids. Accumulating evidence indicates this system is involved in regulating states of motivation and emotion. Acute activation of the KOR produces an increase in motivational behavior to escape a threat, however, KOR activation associated with chronic stress leads to the expression of symptoms indicative of mood disorders. It is well accepted that KOR can produce analgesia and is engaged in chronic pain states including neuropathic pain. Spinal studies have revealed KOR-induced analgesia in reversing pain hypersensitivities associated with peripheral nerve injury. While systemic administration of KOR agonists attenuates nociceptive sensory transmission, this effect appears to be a stress-induced effect as anxiolytic agents, including delta opioid receptor agonists, mitigate KOR agonist-induced analgesia. Additionally, while the role of KOR and dynorphin in driving the dysphoric and aversive components of stress and drug withdrawal has been well characterized, how this system mediates the negative emotional states associated with chronic pain is relatively unexplored. This review provides evidence that dynorphin and the KOR system contribute to the negative affective component of pain and that this receptor system likely contributes to the high comorbidity of mood disorders associated with chronic neuropathic pain. PMID:25452729

  6. Vestibular receptors contribute to cortical auditory evoked potentials.

    PubMed

    Todd, Neil P M; Paillard, Aurore C; Kluk, Karolina; Whittle, Elizabeth; Colebatch, James G

    2014-03-01

    Acoustic sensitivity of the vestibular apparatus is well-established, but the contribution of vestibular receptors to the late auditory evoked potentials of cortical origin is unknown. Evoked potentials from 500 Hz tone pips were recorded using 70 channel EEG at several intensities below and above the vestibular acoustic threshold, as determined by vestibular evoked myogenic potentials (VEMPs). In healthy subjects both auditory mid- and long-latency auditory evoked potentials (AEPs), consisting of Na, Pa, N1 and P2 waves, were observed in the sub-threshold conditions. However, in passing through the vestibular threshold, systematic changes were observed in the morphology of the potentials and in the intensity dependence of their amplitude and latency. These changes were absent in a patient without functioning vestibular receptors. In particular, for the healthy subjects there was a fronto-central negativity, which appeared at about 42 ms, referred to as an N42, prior to the AEP N1. Source analysis of both the N42 and N1 indicated involvement of cingulate cortex, as well as bilateral superior temporal cortex. Our findings are best explained by vestibular receptors contributing to what were hitherto considered as purely auditory evoked potentials and in addition tentatively identify a new component that appears to be primarily of vestibular origin.

  7. Polymorphisms of the OXTR gene explain why sales professionals love to help customers.

    PubMed

    Verbeke, Willem; Bagozzi, Richard P; van den Berg, Wouter E; Lemmens, Aurelie

    2013-01-01

    Polymorphisms of the OXTR gene affect people's social interaction styles in various social encounters: carriers of the OXTR GG, compared to the OXTR AA/AG in general, are more motivated to interact socially and detect social salience. We focus on sales professionals operating in knowledge intensive organizations. Study 1, with a sample of 141 sales people, shows that carriers of the OXTR GG allele, compared to the OXTR AA/AG allele, are more motivated to help customers than to manipulatively impose goods/services on them. Study 2, using genomic functional magnetic resonance imaging (fMRI) on a sample of 21 sales professionals processing facial pictures with different emotional valences, investigates key nuclei of social brain regions (SBRs). Compared to OXTR AA/AG carriers, OXTR GG carriers experience greater effective connectivity between SBRs of interest measured by Granger causality tests using univariate Haugh tests. In addition, the multivariate El-Himdi and Roy tests demonstrate that the amygdala, prefrontal cortex, and pars opercularis (inferior frontal gyrus) play key roles when processing emotional expressions. The bilateral amygdala and medial prefrontal cortex (mPFC) show significantly greater clout-influence on other brain regions-for GG allele carriers than non-carriers; likewise, the bilateral pars opercularis, left amygdala, and left mPFC are more receptive to activity in other brain regions among GG allele carriers than AG/AA allele carriers are. Thus, carriers of the OXTR GG allele are more sensitive to changes in emotional cues, enhancing social salience. To our knowledge, this is the first study on how insights from imaging genetics help understanding of the social motivation of people operating in a professional setting.

  8. Polymorphisms of the OXTR gene explain why sales professionals love to help customers

    PubMed Central

    Verbeke, Willem; Bagozzi, Richard P.; van den Berg, Wouter E.; Lemmens, Aurelie

    2013-01-01

    Polymorphisms of the OXTR gene affect people's social interaction styles in various social encounters: carriers of the OXTR GG, compared to the OXTR AA/AG in general, are more motivated to interact socially and detect social salience. We focus on sales professionals operating in knowledge intensive organizations. Study 1, with a sample of 141 sales people, shows that carriers of the OXTR GG allele, compared to the OXTR AA/AG allele, are more motivated to help customers than to manipulatively impose goods/services on them. Study 2, using genomic functional magnetic resonance imaging (fMRI) on a sample of 21 sales professionals processing facial pictures with different emotional valences, investigates key nuclei of social brain regions (SBRs). Compared to OXTR AA/AG carriers, OXTR GG carriers experience greater effective connectivity between SBRs of interest measured by Granger causality tests using univariate Haugh tests. In addition, the multivariate El-Himdi and Roy tests demonstrate that the amygdala, prefrontal cortex, and pars opercularis (inferior frontal gyrus) play key roles when processing emotional expressions. The bilateral amygdala and medial prefrontal cortex (mPFC) show significantly greater clout—influence on other brain regions—for GG allele carriers than non-carriers; likewise, the bilateral pars opercularis, left amygdala, and left mPFC are more receptive to activity in other brain regions among GG allele carriers than AG/AA allele carriers are. Thus, carriers of the OXTR GG allele are more sensitive to changes in emotional cues, enhancing social salience. To our knowledge, this is the first study on how insights from imaging genetics help understanding of the social motivation of people operating in a professional setting. PMID:24348351

  9. Oxytocin receptor binding sites in the periphery of the neonatal mouse

    PubMed Central

    Greenwood, Maria A.

    2017-01-01

    Oxytocin (OXT) is a pleiotropic regulator of physiology and behavior. An emerging body of evidence demonstrates a role for OXT in the transition to postnatal life of the infant. To identify potential sites of OXT action via the OXT receptor (OXTR) in the newborn mouse, we performed receptor autoradiography on 20 μm sagittal sections of whole postnatal day 0 male and female mice on a C57BL/6J background using the 125iodinated ornithine vasotocin analog ([125I]-OVTA) radioligand. A competitive binding assay on both wild-type (WT) and OXTR knockout (OXTR KO) tissue was used to assess the selectivity of [125I]-OVTA for neonatal OXTR. Radioactive ligand (0.05 nM [125I]-OVTA) was competed against concentrations of 0 nM, 10 nM, and 1000 nM excess unlabeled OXT. Autoradiographs demonstrated the high selectivity of the radioligand for infant peripheral OXTR. Specific ligand binding activity for OXTR was observed in the oronasal cavity, the eye, whisker pads, adrenal gland, and anogenital region in the neonatal OXTR WT mouse, but was absent in neonatal OXTR KO. Nonspecific binding was observed in areas with a high lipid content such as the scapular brown adipose tissue and the liver: in these regions, binding was present in both OXTR WT and KO mice, and could not be competed away with OXT in either WT or KO mice. Collectively, these data confirm novel OXT targets in the periphery of the neonate. These peripheral OXTR sites, coupled with the immaturity of the neonate’s own OXT system, suggest a role for exogenous OXT in modulating peripheral physiology and development. PMID:28235051

  10. Endoplasmic reticulum stress contributes to acetylcholine receptor degradation by promoting endocytosis in skeletal muscle cells.

    PubMed

    Du, Ailian; Huang, Shiqian; Zhao, Xiaonan; Zhang, Yun; Zhu, Lixun; Ding, Ji; Xu, Congfeng

    2016-01-15

    After binding by acetylcholine released from a motor neuron, a nicotinic acetylcholine receptor at the neuromuscular junction produces a localized end-plate potential, which leads to muscle contraction. Improper turnover and renewal of acetylcholine receptors contributes to the pathogenesis of myasthenia gravis. In the present study, we demonstrate that endoplasmic reticulum (ER) stress contributes to acetylcholine receptor degradation in C2C12 myocytes. We further show that ER stress promotes acetylcholine receptor endocytosis and lysosomal degradation, which was dampened by blocking endocytosis or treating with lysosome inhibitor. Knockdown of ER stress proteins inhibited acetylcholine receptor endocytosis and degradation, while rescue assay restored its endocytosis and degradation, confirming the effects of ER stress on promoting endocytosis-mediated degradation of junction acetylcholine receptors. Thus, our studies identify ER stress as a factor promoting acetylcholine receptor degradation through accelerating endocytosis in muscle cells. Blocking ER stress and/or endocytosis might provide a novel therapeutic approach for myasthenia gravis.

  11. Oxytocin receptor gene methylation: converging multilevel evidence for a role in social anxiety.

    PubMed

    Ziegler, Christiane; Dannlowski, Udo; Bräuer, David; Stevens, Stephan; Laeger, Inga; Wittmann, Hannah; Kugel, Harald; Dobel, Christian; Hurlemann, René; Reif, Andreas; Lesch, Klaus-Peter; Heindel, Walter; Kirschbaum, Clemens; Arolt, Volker; Gerlach, Alexander L; Hoyer, Jürgen; Deckert, Jürgen; Zwanzger, Peter; Domschke, Katharina

    2015-05-01

    Social anxiety disorder (SAD) is a commonly occurring and highly disabling disorder. The neuropeptide oxytocin and its receptor (OXTR) have been implicated in social cognition and behavior. This study-for the first time applying a multilevel epigenetic approach-investigates the role of OXTR gene methylation in categorical, dimensional, and intermediate neuroendocrinological/neural network phenotypes of social anxiety. A total of 110 unmedicated patients with SAD and matched 110 controls were analyzed for OXTR methylation by direct sequencing of sodium bisulfite-converted DNA extracted from whole blood. Furthermore, OXTR methylation was investigated regarding SAD-related traits (Social Phobia Scale (SPS) and Social Interaction Anxiety Scale (SIAS)), salivary cortisol response during the Trier social stress test (TSST), and amygdala responsiveness to social phobia related verbal stimuli using fMRI. Significantly decreased OXTR methylation particularly at CpG Chr3: 8 809 437 was associated with (1) the categorical phenotype of SAD (p<0.001, Cohen's d=0.535), (2) increased SPS and SIAS scores (p<0.001), (3) increased cortisol response to the TSST (p=0.02), and (4) increased amygdala responsiveness during social phobia-related word processing (right: p(corr)<0.001; left: p(corr)=0.005). Assuming that decreased OXTR methylation confers increased OXTR expression, the present finding may reflect a compensatory upregulation for pathologically reduced oxytocin levels or a causally relevant increased OXTR activation in SAD and related traits. OXTR methylation patterns might thus serve as peripheral surrogates of oxytocin tone and aid in establishing accessible biomarkers of SAD risk allowing for indicated preventive interventions and personalized treatment approaches targeting the oxytocin system.

  12. Antisocial behavior and polymorphisms in the oxytocin receptor gene: findings in two independent samples.

    PubMed

    Hovey, D; Lindstedt, M; Zettergren, A; Jonsson, L; Johansson, A; Melke, J; Kerekes, N; Anckarsäter, H; Lichtenstein, P; Lundström, S; Westberg, L

    2016-07-01

    The quantitative genetic contribution to antisocial behavior is well established, but few, if any, genetic variants are established as risk factors. Emerging evidence suggests that the neuropeptide oxytocin (OXT) may modulate interpersonal aggression. We here investigated whether single-nucleotide polymorphisms (SNPs) in the OXT receptor gene (OXTR) are associated with the expression of antisocial behavior. A discovery sample, including both sexes, was drawn from the Child and Adolescent Twin Study in Sweden (CATSS; n=2372), and a sample from the Twin Study of Child and Adolescent Development (TCHAD; n=1232) was used for replication. Eight SNPs in OXTR, selected on previous associations with social and antisocial behavior, were genotyped in the participants of CATSS. Significant polymorphisms were subsequently genotyped in TCHAD for replication. Participants completed self-assessment questionnaires-Life History of Aggression (LHA; available only in CATSS), and Self-Reported Delinquency (SRD; available in both samples)-designed to capture antisocial behavior as continuous traits. In the discovery sample, the rs7632287 AA genotype was associated with higher frequency of antisocial behavior in boys, and this was then replicated in the second sample. In particular, overt aggression (directly targeting another individual) was strongly associated with this genotype in boys (P=6.2 × 10(-7) in the discovery sample). Meta-analysis of the results for antisocial behavior from both samples yielded P=2.5 × 10(-5). Furthermore, an association between rs4564970 and LHA (P=0.00013) survived correction in the discovery sample, but there was no association with the SRD in the replication sample. We conclude that the rs7632287 and rs4564970 polymorphisms in OXTR may independently influence antisocial behavior in adolescent boys. Further replication of our results will be crucial to understanding how aberrant social behavior arises, and would support the OXT receptor as one

  13. Natural variation in maternal care and cross-tissue patterns of oxytocin receptor gene methylation in rats.

    PubMed

    Beery, Annaliese K; McEwen, Lisa M; MacIsaac, Julia L; Francis, Darlene D; Kobor, Michael S

    2016-01-01

    This article is part of a Special Issue "Parental Care". Since the first report of maternal care effects on DNA methylation in rats, epigenetic modifications of the genome in response to life experience have become the subject of intense focus across many disciplines. Oxytocin receptor expression varies in response to early experience, and both oxytocin signaling and methylation status of the oxytocin receptor gene (Oxtr) in blood have been related to disordered social behavior. It is unknown whether Oxtr DNA methylation varies in response to early life experience, and whether currently employed peripheral measures of Oxtr methylation reflect variation in the brain. We examined the effects of early life rearing experience via natural variation in maternal licking and grooming during the first week of life on behavior, physiology, gene expression, and epigenetic regulation of Oxtr across blood and brain tissues (mononucleocytes, hippocampus, striatum, and hypothalamus). Rats reared by "high" licking-grooming (HL) and "low" licking-grooming (LL) rat dams exhibited differences across study outcomes: LL offspring were more active in behavioral arenas, exhibited lower body mass in adulthood, and showed reduced corticosterone responsivity to a stressor. Oxtr DNA methylation was significantly lower at multiple CpGs in the blood of LL versus HL males, but no differences were found in the brain. Across groups, Oxtr transcript levels in the hypothalamus were associated with reduced corticosterone secretion in response to stress, congruent with the role of oxytocin signaling in this region. Methylation of specific CpGs at a high or low level was consistent across tissues, especially within the brain. However, individual variation in DNA methylation relative to these global patterns was not consistent across tissues. These results suggest that blood Oxtr DNA methylation may reflect early experience of maternal care, and that Oxtr methylation across tissues is highly concordant

  14. Natural variation in maternal care and cross-tissue patterns of oxytocin receptor gene methylation in rats

    PubMed Central

    Beery, Annaliese K.; McEwen, Lisa M.; MacIsaac, Julia L; Francis, Darlene D.; Kobor, Michael S.

    2015-01-01

    Since the first report of maternal care effects on DNA methylation in rats, epigenetic modifications of the genome in response to life experience have become the subject of intense focus across many disciplines. Oxytocin receptor expression varies in response to early experience, and both oxytocin signaling and methylation status of the oxytocin receptor gene (Oxtr) in blood have been related to disordered social behavior. It is unknown whether Oxtr methylation varies in response to early life experience, and whether currently employed peripheral measures of Oxtr methylation reflect variation in the brain. We examined the effects of early life rearing experience via natural variation in maternal licking and grooming during the first week of life on behavior, physiology, gene expression, and epigenetic regulation of Oxtr across blood and brain tissues (mononucleocytes, hippocampus, striatum, and hypothalamus). Rats reared by “high” licking-grooming (HL) and “low” licking-grooming (LL) rat dams exhibited differences across study outcomes: LL offspring were more active in behavioral arenas, exhibited lower body mass in adulthood, and showed reduced corticosterone responsivity to a stressor. Oxtr methylation was significantly lower at multiple CpGs in the blood of LL versus HL rats, but no differences were found in the brain. Across groups, Oxtr transcript levels in the hypothalamus were associated with reduced corticosterone secretion in response to stress, congruent with the role of oxytocin signaling in this region. Methylation of specific CpGs at a high or low level was consistent across tissues, especially within the brain. However, individual variation in methylation relative to these global patterns was not consistent across tissues. These results suggest that blood Oxtr methylation may reflect early experience of maternal care, and that Oxtr methylation across tissues is highly concordant for specific CpGs, but that inferences across tissues are not

  15. Neuroanatomical distribution of oxytocin and vasopressin 1a receptors in the socially monogamous coppery titi monkey (Callicebus cupreus)

    PubMed Central

    Freeman, Sara M.; Walum, Hasse; Inoue, Kiyoshi; Smith, Aaron L.; Goodman, Mark M.; Bales, Karen L.; Young, Larry J.

    2014-01-01

    The coppery titi monkey (Callicebus cupreus) is a socially monogamous New World primate that has been studied in the field and the laboratory to investigate the behavioral neuroendocrinology of primate pair bonding and parental care. Arginine vasopressin has been shown to influence male titi monkey pair-bonding behavior, and studies are currently underway to examine the effects of oxytocin on titi monkey behavior and physiology. Here, we use receptor autoradiography to identify the distribution of arginine vasopressin 1a (AVPR1a) and oxytocin receptors (OXTR) in hemispheres of titi monkey brain (n=5). AVPR1a are diffuse and widespread throughout the brain, but the OXTR distribution is much more limited, with the densest binding being in the hippocampal formation (dentate gyrus, CA1 field) and the presubiculum (layers I and III). Moderate OXTR binding was detected in the nucleus basalis of Meynert, pulvinar, superior colliculus, layer 4C of primary visual cortex, periaqueductal gray, pontine gray, nucleus prepositus, and spinal trigeminal nucleus. OXTR mRNA overlapped with OXTR radioligand binding, confirming that the radioligand was detecting OXTR protein. AVPR1a binding is present throughout the cortex, especially in cingulate, insular, and occipital cortices, as well as in the caudate, putamen, nucleus accumbens, central amygdala, endopiriform nucleus, hippocampus (CA4 field), globus pallidus, lateral geniculate nucleus, infundibulum, habenula, periaqueductal gray, substantia nigra, olivary nucleus, hypoglossal nucleus, and cerebellum. Furthermore, we show that, in titi monkey brain, the OXTR antagonist ALS-II-69 is highly selective for OXTR and that the AVPR1a antagonist SR49059 is highly selective for AVPR1a. Based on these results and the fact that both ALS-II-69 and SR49059 are non-peptide, small-molecule antagonists that should be capable of crossing the blood brain barrier, these two compounds emerge as excellent candidates for the pharmacological

  16. Delta opioid receptor analgesia: recent contributions from pharmacology and molecular approaches

    PubMed Central

    Gavériaux-Ruff, Claire; Kieffer, Brigitte Lina

    2012-01-01

    Delta opioid receptors represent a promising target for the development of novel analgesics. A number of tools have been developed recently that have significantly improved our knowledge of delta receptor function in pain control. These include several novel delta agonists with potent analgesic properties, as well as genetic mouse models with targeted mutations in the delta opioid receptor gene. Also, recent findings have further documented the regulation of delta receptor function at cellular level, which impacts on the pain-reducing activity of the receptor. These regulatory mechanisms occur at transcriptional and post-translational levels, along agonist-induced receptor activation, signaling and trafficking, or in interaction with other receptors and neuromodulatory systems. All these tools for in vivo research, as well as proposed mechanisms at molecular level, have tremendously increased our understanding of delta receptor physiology, and contribute to designing innovative strategies for the treatment of chronic pain and other diseases such as mood disorders. PMID:21836459

  17. Opioid receptor internalization contributes to dermorphin-mediated antinociception

    PubMed Central

    Macey, Tara A.; Ingram, Susan L.; Bobeck, Erin N.; Hegarty, Deborah M.; Aicher, Sue A.; Arttamangkul, Seksiri; Morgan, Michael M.

    2010-01-01

    Microinjection of opioids into the ventrolateral periaqueductal gray (vlPAG) produces antinociception in part by binding to mu-opioid receptors (MOPrs). Although both high and low efficacy agonists produce antinociception, low efficacy agonists such as morphine produce limited MOPr internalization suggesting that MOPr internalization and signaling leading to antinociception are independent. This hypothesis was tested in awake, behaving rats using DERM-A594, a fluorescently labeled dermorphin analog, and internalization blockers. Microinjection of DERM-A594 into the vlPAG produced both antinociception and internalization of DERM-A594. Administration of the irreversible opioid receptor antagonist beta-CNA prior to DERM-A594 microinjection reduced both the antinociceptive effect and the number of DERM-A594 labeled cells demonstrating that both effects are opioid receptor-mediated. Pretreatment with the internalization blockers dynamin dominant-negative inhibitory peptide (dynamin-DN) and concanavalinA (ConA) attenuated both DERM-A594 internalization and antinociception. Microinjection of dynamin-DN and ConA also decreased the antinociceptive potency of the unlabeled opioid agonist dermorphin when microinjected into the vlPAG as demonstrated by rightward shifts in the dose-response curves. In contrast, administration of dynamin-DN had no effect on the antinociceptive effect of microinjecting the GABAA antagonist bicuculline into the vlPAG. The finding that dermorphin-induced antinociception is attenuated by blocking receptor internalization indicates that key parts of opioid receptor-mediated signaling depend on internalization. PMID:20394808

  18. The Contribution of Vascular Receptors to +Gz Tolerance

    DTIC Science & Technology

    1975-11-30

    the possible effects of fatigue and habituation of the receptor on the magnitude of the cardiovascular antigravity " responses; and (4) contrast...responses obtained with and J without an antigravity suit. !A ieW r j-p B. Sixteen-Month Performance Pro&ram Varioun factors precluded the opportunity to... antigravity suit was used on 2 dogs. METHODS This investigation required the degree of impairment in +Gz tolerance of instrumented dogs to be evaluated

  19. N-Methyl-D-Aspartate Receptor Activation May Contribute to Glufosinate Neurotoxicity

    EPA Science Inventory

    N-Methyl-D-aspartate Receptor Activation May Contribute to Glufosinate Neurotoxicity Glufosinate (GLF) at high levels in mammals causes convulsions through a mechanism that is not completely understood. The structural similarity of GLF to glutamate (GLU) implicates the glutamate...

  20. Oxytocin efficacy is modulated by dosage and oxytocin receptor genotype in young adults with high-functioning autism: a 24-week randomized clinical trial

    PubMed Central

    Kosaka, H; Okamoto, Y; Munesue, T; Yamasue, H; Inohara, K; Fujioka, T; Anme, T; Orisaka, M; Ishitobi, M; Jung, M; Fujisawa, T X; Tanaka, S; Arai, S; Asano, M; Saito, D N; Sadato, N; Tomoda, A; Omori, M; Sato, M; Okazawa, H; Higashida, H; Wada, Y

    2016-01-01

    Recent studies have suggested that long-term oxytocin administration can alleviate the symptoms of autism spectrum disorder (ASD); however, factors influencing its efficacy are still unclear. We conducted a single-center phase 2, pilot, randomized, double-blind, placebo-controlled, parallel-group, clinical trial in young adults with high-functioning ASD, to determine whether oxytocin dosage and genetic background of the oxytocin receptor affects oxytocin efficacy. This trial consisted of double-blind (12 weeks), open-label (12 weeks) and follow-up phases (8 weeks). To examine dose dependency, 60 participants were randomly assigned to high-dose (32 IU per day) or low-dose intranasal oxytocin (16 IU per day), or placebo groups during the double-blind phase. Next, we measured single-nucleotide polymorphisms (SNPs) in the oxytocin receptor gene (OXTR). In the intention-to-treat population, no outcomes were improved after oxytocin administration. However, in male participants, Clinical Global Impression-Improvement (CGI-I) scores in the high-dose group, but not the low-dose group, were significantly higher than in the placebo group. Furthermore, we examined whether oxytocin efficacy, reflected in the CGI-I scores, is influenced by estimated daily dosage and OXTR polymorphisms in male participants. We found that >21 IU per day oxytocin was more effective than ⩽21 IU per day, and that a SNP in OXTR (rs6791619) predicted CGI-I scores for ⩽21 IU per day oxytocin treatment. No severe adverse events occurred. These results suggest that efficacy of long-term oxytocin administration in young men with high-functioning ASD depends on the oxytocin dosage and genetic background of the oxytocin receptor, which contributes to the effectiveness of oxytocin treatment of ASD. PMID:27552585

  1. Leaky ryanodine receptors contribute to diaphragmatic weakness during mechanical ventilation

    PubMed Central

    Matecki, Stefan; Dridi, Haikel; Jung, Boris; Saint, Nathalie; Reiken, Steven R.; Scheuermann, Valérie; Mrozek, Ségolène; Umanskaya, Alisa; Petrof, Basil J.; Jaber, Samir; Marks, Andrew R.; Lacampagne, Alain

    2016-01-01

    Ventilator-induced diaphragmatic dysfunction (VIDD) refers to the diaphragm muscle weakness that occurs following prolonged controlled mechanical ventilation (MV). The presence of VIDD impedes recovery from respiratory failure. However, the pathophysiological mechanisms accounting for VIDD are still not fully understood. Here, we show in human subjects and a mouse model of VIDD that MV is associated with rapid remodeling of the sarcoplasmic reticulum (SR) Ca2+ release channel/ryanodine receptor (RyR1) in the diaphragm. The RyR1 macromolecular complex was oxidized, S-nitrosylated, Ser-2844 phosphorylated, and depleted of the stabilizing subunit calstabin1, following MV. These posttranslational modifications of RyR1 were mediated by both oxidative stress mediated by MV and stimulation of adrenergic signaling resulting from the anesthesia. We demonstrate in the murine model that such abnormal resting SR Ca2+ leak resulted in reduced contractile function and muscle fiber atrophy for longer duration of MV. Treatment with β-adrenergic antagonists or with S107, a small molecule drug that stabilizes the RyR1–calstabin1 interaction, prevented VIDD. Diaphragmatic dysfunction is common in MV patients and is a major cause of failure to wean patients from ventilator support. This study provides the first evidence to our knowledge of RyR1 alterations as a proximal mechanism underlying VIDD (i.e., loss of function, muscle atrophy) and identifies RyR1 as a potential target for therapeutic intervention. PMID:27457930

  2. The Differential Impact of Oxytocin Receptor Gene in Violence-Exposed Boys and Girls.

    PubMed

    Merrill, Livia C; Jones, Christopher W; Drury, Stacy S; Theall, Katherine P

    2017-03-21

    Childhood violence exposure is a prevalent public health problem. Understanding the lasting impact of violence requires an enhanced appreciation for the complex effects of violence across behavioral, physiologic, and molecular outcomes. This subject matched, cross-sectional study of 80 children explored the impact of violence exposure across behavioral, physiologic, and cellular outcomes. Externalizing behavior, diurnal cortisol rhythm, and telomere length (TL) were examined in a community recruited cohort of Black youth. Given evidence that genetic variation contributes to individual differences in response to the environment, we further tested whether a polymorphism in the oxytocin receptor gene (OXTR rs53576) moderated associations between violence and youth outcomes. Exposure to violence was directly associated with increased externalizing behavior, but no direct association of violence was found with cortisol or TL. Oxytocin genotype, however, moderated the association between violence and both cortisol and TL, suggesting that pathways linked to oxytocin may contribute to individual differences in the physiologic and molecular consequences of violence exposure. Sex differences with OXTR in cortisol and TL outcomes were also detected. Taken together, these findings suggest that there are complex pathways through which violence exposure impacts children, and that these pathways differ by both genetic variation and the sex of the child.

  3. Epigenetic modification of the oxytocin receptor gene influences the perception of anger and fear in the human brain.

    PubMed

    Puglia, Meghan H; Lillard, Travis S; Morris, James P; Connelly, Jessica J

    2015-03-17

    In humans, the neuropeptide oxytocin plays a critical role in social and emotional behavior. The actions of this molecule are dependent on a protein that acts as its receptor, which is encoded by the oxytocin receptor gene (OXTR). DNA methylation of OXTR, an epigenetic modification, directly influences gene transcription and is variable in humans. However, the impact of this variability on specific social behaviors is unknown. We hypothesized that variability in OXTR methylation impacts social perceptual processes often linked with oxytocin, such as perception of facial emotions. Using an imaging epigenetic approach, we established a relationship between OXTR methylation and neural activity in response to emotional face processing. Specifically, high levels of OXTR methylation were associated with greater amounts of activity in regions associated with face and emotion processing including amygdala, fusiform, and insula. Importantly, we found that these higher levels of OXTR methylation were also associated with decreased functional coupling of amygdala with regions involved in affect appraisal and emotion regulation. These data indicate that the human endogenous oxytocin system is involved in attenuation of the fear response, corroborating research implicating intranasal oxytocin in the same processes. Our findings highlight the importance of including epigenetic mechanisms in the description of the endogenous oxytocin system and further support a central role for oxytocin in social cognition. This approach linking epigenetic variability with neural endophenotypes may broadly explain individual differences in phenotype including susceptibility or resilience to disease.

  4. Oxytocin receptor genetic and epigenetic variation: association with child abuse and adult psychiatric symptoms

    PubMed Central

    Smearman, Erica L.; Almli, Lynn M.; Conneely, Karen N.; Brody, Gene H.; Sales, Jessica M.; Bradley, Bekh; Ressler, Kerry J.; Smith, Alicia K.

    2015-01-01

    Childhood abuse can alter biological systems and increase risk for adult psychopathology. Epigenetic mechanisms, alterations in DNA structure that regulate the gene expression, are a potential mechanism underlying this risk. While abuse associates with methylation of certain genes, particularly those in the stress response system, no study to date has evaluated abuse and methylation of the oxytocin receptor (OXTR). However, studies support a role for OXTR in the link between abuse and adverse adult outcomes, showing that abuse can confer greater risk for psychiatric symptoms in those with specific OXTR genotypes. Our study therefore sought to (1) assess the role of epigenetics in the link between abuse and psychopathology and (2) to begin to integrate the genetic and epigenetic literature by exploring associations between OXTR genotypes and DNA CpG methylation. Data on 18 OXTR CpG sites, 44 SNPs, childhood abuse, and adult depression and anxiety symptoms were assessed in 393 African American adults (age = 41±12.8). Overall, 68% of genotypes associated with methylation of nearby CpG sites, with a subset surviving multiple test correction. Child abuse associated with higher methylation of two CpG sites yet did not survive correction or serve as a mediator of psychopathology. However, abuse interacted with CpG methylation to predict psychopathology. These findings suggest a role for OXTR in understanding the influence of early environments on adult psychiatric symptoms. PMID:26822448

  5. Differential Contribution of Subunit Interfaces to α9α10 Nicotinic Acetylcholine Receptor Function.

    PubMed

    Boffi, Juan Carlos; Marcovich, Irina; Gill-Thind, JasKiran K; Corradi, Jeremías; Collins, Toby; Lipovsek, María Marcela; Moglie, Marcelo; Plazas, Paola V; Craig, Patricio O; Millar, Neil S; Bouzat, Cecilia; Elgoyhen, Ana Belén

    2017-03-01

    Nicotinic acetylcholine receptors can be assembled from either homomeric or heteromeric pentameric subunit combinations. At the interface of the extracellular domains of adjacent subunits lies the acetylcholine binding site, composed of a principal component provided by one subunit and a complementary component of the adjacent subunit. Compared with neuronal nicotinic acetylcholine cholinergic receptors (nAChRs) assembled from α and β subunits, the α9α10 receptor is an atypical member of the family. It is a heteromeric receptor composed only of α subunits. Whereas mammalian α9 subunits can form functional homomeric α9 receptors, α10 subunits do not generate functional channels when expressed heterologously. Hence, it has been proposed that α10 might serve as a structural subunit, much like a β subunit of heteromeric nAChRs, providing only complementary components to the agonist binding site. Here, we have made use of site-directed mutagenesis to examine the contribution of subunit interface domains to α9α10 receptors by a combination of electrophysiological and radioligand binding studies. Characterization of receptors containing Y190T mutations revealed unexpectedly that both α9 and α10 subunits equally contribute to the principal components of the α9α10 nAChR. In addition, we have shown that the introduction of a W55T mutation impairs receptor binding and function in the rat α9 subunit but not in the α10 subunit, indicating that the contribution of α9 and α10 subunits to complementary components of the ligand-binding site is nonequivalent. We conclude that this asymmetry, which is supported by molecular docking studies, results from adaptive amino acid changes acquired only during the evolution of mammalian α10 subunits.

  6. Differential Contribution of Subunit Interfaces to α9α10 Nicotinic Acetylcholine Receptor Function

    PubMed Central

    Boffi, Juan Carlos; Marcovich, Irina; Gill-Thind, JasKiran K.; Corradi, Jeremías; Collins, Toby; Lipovsek, María Marcela; Moglie, Marcelo; Plazas, Paola V.; Craig, Patricio O.; Millar, Neil S.; Bouzat, Cecilia

    2017-01-01

    Nicotinic acetylcholine receptors can be assembled from either homomeric or heteromeric pentameric subunit combinations. At the interface of the extracellular domains of adjacent subunits lies the acetylcholine binding site, composed of a principal component provided by one subunit and a complementary component of the adjacent subunit. Compared with neuronal nicotinic acetylcholine cholinergic receptors (nAChRs) assembled from α and β subunits, the α9α10 receptor is an atypical member of the family. It is a heteromeric receptor composed only of α subunits. Whereas mammalian α9 subunits can form functional homomeric α9 receptors, α10 subunits do not generate functional channels when expressed heterologously. Hence, it has been proposed that α10 might serve as a structural subunit, much like a β subunit of heteromeric nAChRs, providing only complementary components to the agonist binding site. Here, we have made use of site-directed mutagenesis to examine the contribution of subunit interface domains to α9α10 receptors by a combination of electrophysiological and radioligand binding studies. Characterization of receptors containing Y190T mutations revealed unexpectedly that both α9 and α10 subunits equally contribute to the principal components of the α9α10 nAChR. In addition, we have shown that the introduction of a W55T mutation impairs receptor binding and function in the rat α9 subunit but not in the α10 subunit, indicating that the contribution of α9 and α10 subunits to complementary components of the ligand-binding site is nonequivalent. We conclude that this asymmetry, which is supported by molecular docking studies, results from adaptive amino acid changes acquired only during the evolution of mammalian α10 subunits. PMID:28069778

  7. The α5 subunit-containing GABAA receptors contribute to chronic pain

    PubMed Central

    Bravo-Hernández, Mariana; Corleto, José A.; Barragán-Iglesias, Paulino; González-Ramírez, Ricardo; Pineda-Farias, Jorge B.; Felix, Ricardo; Calcutt, Nigel A.; Delgado-Lezama, Rodolfo; Marsala, Martin; Granados-Soto, Vinicio

    2016-01-01

    It has been recently proposed that α5-subunit containing GABAA receptors (α5-GABAA receptors) that mediate tonic inhibition might be involved in pain. The purpose of this study was to investigate the contribution of α5-GABAA receptors in the loss of GABAergic inhibition and in formalin-, Complete Freund’s adjuvant (CFA)- and L5/L6 spinal nerve ligation-induced long-lasting hypersensitivity. Formalin or CFA injection and L5/L6 spinal nerve ligation produced long-lasting allodynia and hyperalgesia. Moreover, formalin injection impaired the rate-dependent depression (RDD) of the Hofmann reflex. Peripheral and intrathecal pre-treatment or post-treatment with the α5-GABAA receptor antagonist, L-655,708 (0.15–15 nmol) prevented and reversed, respectively, these long-lasting behaviors. Formalin injection increased α5-GABAA receptors mRNA expression in the spinal cord and dorsal root ganglia (DRG) mainly at 3 days. α5-GABAA receptors were localized in the dorsal spinal cord and DRG co-labeling with NeuN, CGRP and IB4 suggesting their presence in peptidergic and non-peptidergic neurons. These receptors were found mainly in small- and medium-size neurons. Formalin injection enhanced α5-GABAA receptors fluorescence intensity in spinal cord and DRG at 3 and 6 days. Intrathecal administration of L-655,708 (15 nmol) prevented and reversed formalin-induced impairment of RDD. These results suggest that α5-GABAA receptors play a role in the loss of GABAergic inhibition and contribute to long-lasting secondary allodynia and hyperalgesia. PMID:26545088

  8. The α5 subunit containing GABAA receptors contribute to chronic pain.

    PubMed

    Bravo-Hernández, Mariana; Corleto, José A; Barragán-Iglesias, Paulino; González-Ramírez, Ricardo; Pineda-Farias, Jorge B; Felix, Ricardo; Calcutt, Nigel A; Delgado-Lezama, Rodolfo; Marsala, Martin; Granados-Soto, Vinicio

    2016-03-01

    It has been recently proposed that α5-subunit containing GABAA receptors (α5-GABAA receptors) that mediate tonic inhibition might be involved in pain. The purpose of this study was to investigate the contribution of α5-GABAA receptors in the loss of GABAergic inhibition and in formalin-induced, complete Freund's adjuvant (CFA)-induced and L5 and L6 spinal nerve ligation-induced long-lasting hypersensitivity. Formalin or CFA injection and L5 and L6 spinal nerve ligation produced long-lasting allodynia and hyperalgesia. Moreover, formalin injection impaired the rate-dependent depression of the Hofmann reflex. Peripheral and intrathecal pretreatment or post-treatment with the α5-GABAA receptor antagonist, L-655,708 (0.15-15 nmol), prevented and reversed, respectively, these long-lasting behaviors. Formalin injection increased α5-GABAA receptor mRNA expression in the spinal cord and dorsal root ganglia (DRG) mainly at 3 days. The α5-GABAA receptors were localized in the dorsal spinal cord and DRG colabeling with NeuN, CGRP, and IB4 which suggests their presence in peptidergic and nonpeptidergic neurons. These receptors were found mainly in small and medium sized neurons. Formalin injection enhanced α5-GABAA receptor fluorescence intensity in spinal cord and DRG at 3 and 6 days. Intrathecal administration of L-655,708 (15 nmol) prevented and reversed formalin-induced impairment of rate-dependent depression. These results suggest that α5-GABAA receptors play a role in the loss of GABAergic inhibition and contribute to long-lasting secondary allodynia and hyperalgesia.

  9. Functional characterization of insulin receptor gene mutations contributing to Rabson-Mendenhall syndrome - phenotypic heterogeneity of insulin receptor gene mutations.

    PubMed

    Jiang, Shan; Fang, Qichen; Zhang, Feng; Wan, Hui; Zhang, Rong; Wang, Congrong; Bao, Yuqian; Zhang, Lei; Ma, Xiaojing; Lu, Junxi; Gao, Fei; Xiang, Kunsan; Jia, Weiping

    2011-01-01

    Rabson-Mendenhall syndrome (RMS) is a rare disorder that presents as severe insulin resistance as a result of mutations present in the insulin receptor (INSR). A Chinese girl with RMS presented with profound diabetes, hyperinsulinemia, acanthosis nigricans, hirsutism, and abnormalities of teeth and nails. Direct sequencing of the patient's INSR detected heterozygote mutations at Arg83Gln (R83Q) and Ala1028Val (A1028V), with the former representing a novel mutation. Functional studies of Chinese hamster ovary (CHO) cells transfected with wild-type (WT) and mutant forms of INSR were performed to evaluate the effects of these mutations on receptor expression and activation. Receptor expression, insulin binding activity, and phosphorylation of the R83Q variant were comparable to WT. In contrast, expression of the A1028V receptor was much lower than that of WT INSR, and impairment of insulin binding and autophosphorylation were nearly commensurate with the decrease in expression detected. Reductions in the phosphorylation of IRS-1, Akt, and Erk1/2 (60%, 40%, and 50% of WT, respectively) indicate that the A1028V receptor contributes to impaired signal transduction. In conclusion, INSR mutations associated with RMS were identified. Moreover, the A1028V mutation associated with a decrease in expression of INSR potentially accounts for loss of function of the INSR.

  10. Contribution of dopamine D1 and D2 receptors to amygdala activity in human.

    PubMed

    Takahashi, Hidehiko; Takano, Harumasa; Kodaka, Fumitoshi; Arakawa, Ryosuke; Yamada, Makiko; Otsuka, Tatsui; Hirano, Yoshiyuki; Kikyo, Hideyuki; Okubo, Yoshiro; Kato, Motoichiro; Obata, Takayuki; Ito, Hiroshi; Suhara, Tetsuya

    2010-02-24

    Several animal studies have demonstrated functional roles of dopamine (DA) D1 and D2 receptors in amygdala activity. However, the contribution of DA D1 and D2 receptors to amygdala response induced by affective stimuli in human is unknown. To investigate the contribution of DA receptor subtypes to amygdala reactivity in human, we conducted a multimodal in vivo neuroimaging study in which DA D1 and D2 receptor bindings in the amygdala were measured with positron emission tomography (PET), and amygdala response induced by fearful faces was assessed by functional magnetic resonance imaging (fMRI) in healthy volunteers. We used multimodality voxelwise correlation analysis between fMRI signal and DA receptor binding measured by PET. DA D1 binding in the amygdala was positively correlated with amygdala signal change in response to fearful faces, but DA D2 binding in the amygdala was not related to amygdala signal change. DA D1 receptors might play a major role in enhancing amygdala response when sensory inputs are affective.

  11. Tachykinins and Their Receptors: Contributions to Physiological Control and the Mechanisms of Disease

    PubMed Central

    Steinhoff, Martin S.; von Mentzer, Bengt; Geppetti, Pierangelo; Pothoulakis, Charalabos; Bunnett, Nigel W.

    2014-01-01

    The tachykinins, exemplified by substance P, are one of the most intensively studied neuropeptide families. They comprise a series of structurally related peptides that derive from alternate processing of three Tac genes and are expressed throughout the nervous and immune systems. Tachykinins interact with three neurokinin G protein-coupled receptors. The signaling, trafficking, and regulation of neurokinin receptors have also been topics of intense study. Tachykinins participate in important physiological processes in the nervous, immune, gastrointestinal, respiratory, urogenital, and dermal systems, including inflammation, nociception, smooth muscle contractility, epithelial secretion, and proliferation. They contribute to multiple diseases processes, including acute and chronic inflammation and pain, fibrosis, affective and addictive disorders, functional disorders of the intestine and urinary bladder, infection, and cancer. Neurokinin receptor antagonists are selective, potent, and show efficacy in models of disease. In clinical trials there is a singular success: neurokinin 1 receptor antagonists to treat nausea and vomiting. New information about the involvement of tachykinins in infection, fibrosis, and pruritus justifies further trials. A deeper understanding of disease mechanisms is required for the development of more predictive experimental models, and for the design and interpretation of clinical trials. Knowledge of neurokinin receptor structure, and the development of targeting strategies to disrupt disease-relevant subcellular signaling of neurokinin receptors, may refine the next generation of neurokinin receptor antagonists. PMID:24382888

  12. Contribution of metabotropic GABA(B) receptors to neuronal network construction.

    PubMed

    Gaiarsa, Jean-Luc; Kuczewski, Nicola; Porcher, Christophe

    2011-11-01

    In the 1980s, Bowery and colleagues discovered the presence of a novel, bicuculline-resistant and baclofen-sensitive type of GABA receptor on peripheral nerve terminals, the GABA(B) receptor. Since this pioneering work, GABA(B) receptors have been identified in the Central Nervous System (CNS), where they provide an important inhibitory control of postsynaptic excitability and presynaptic transmitter release. GABA(B) receptors have been implicated in a number of important processes in the adult brain such as the regulation of synaptic plasticity and modulation of rhythmic activity. As a result of these studies, several potential therapeutic applications of GABA(B) receptor ligands have been identified. Recent advances have further shown that GABA(B) receptors play more than a classical inhibitory role in adult neurotransmission, and can in fact function as an important developmental signal early in life. Here we summarize current knowledge on the contribution of GABA(B) receptors to the construction and function of developing neuronal networks.

  13. Scavenger receptor function of mouse Fcγ receptor III contributes to progression of atherosclerosis in apolipoprotein E hyperlipidemic mice.

    PubMed

    Zhu, Xinmei; Ng, Hang Pong; Lai, Yen-Chun; Craigo, Jodi K; Nagilla, Pruthvi S; Raghani, Pooja; Nagarajan, Shanmugam

    2014-09-01

    Recent studies showed loss of CD36 or scavenger receptor-AI/II (SR-A) does not ameliorate atherosclerosis in a hyperlipidemic mouse model, suggesting receptors other than CD36 and SR-A may also contribute to atherosclerosis. In this report, we show that apolipoprotein E (apoE)-CD16 double knockout (DKO; apoE-CD16 DKO) mice have reduced atherosclerotic lesions compared with apoE knockout mice. In vivo and in vitro foam cell analyses showed apoE-CD16 DKO macrophages accumulated less neutral lipids. Reduced foam cell formation in apoE-CD16 DKO mice is not due to change in expression of CD36, SR-A, and LOX-1. This led to a hypothesis that CD16 may have scavenger receptor activity. We presented evidence that a soluble form of recombinant mouse CD16 (sCD16) bound to malondialdehyde-modified low-density lipoprotein (MDALDL), and this binding is blocked by molar excess of MDA- modified BSA and anti-MDA mAbs, suggesting CD16 specifically recognizes MDA epitopes. Interestingly, sCD16 inhibited MDALDL binding to macrophage cell line, as well as soluble forms of recombinant mouse CD36, SR-A, and LOX-1, indicating CD16 can cross-block MDALDL binding to other scavenger receptors. Anti-CD16 mAb inhibited immune complex binding to sCD16, whereas it partially inhibited MDALDL binding to sCD16, suggesting MDALDL binding site may be in close proximity to the immune complex binding site in CD16. Loss of CD16 expression resulted in reduced levels of MDALDL-induced proinflammatory cytokine expression. Finally, CD16-deficient macrophages showed reduced MDALDL-induced Syk phosphorylation. Collectively, our findings suggest scavenger receptor activity of CD16 may, in part, contribute to the progression of atherosclerosis.

  14. Oxytocin receptor gene sequences in owl monkeys and other primates show remarkable interspecific regulatory and protein coding variation.

    PubMed

    Babb, Paul L; Fernandez-Duque, Eduardo; Schurr, Theodore G

    2015-10-01

    The oxytocin (OT) hormone pathway is involved in numerous physiological processes, and one of its receptor genes (OXTR) has been implicated in pair bonding behavior in mammalian lineages. This observation is important for understanding social monogamy in primates, which occurs in only a small subset of taxa, including Azara's owl monkey (Aotus azarae). To examine the potential relationship between social monogamy and OXTR variation, we sequenced its 5' regulatory (4936bp) and coding (1167bp) regions in 25 owl monkeys from the Argentinean Gran Chaco, and examined OXTR sequences from 1092 humans from the 1000 Genomes Project. We also assessed interspecific variation of OXTR in 25 primate and rodent species that represent a set of phylogenetically and behaviorally disparate taxa. Our analysis revealed substantial variation in the putative 5' regulatory region of OXTR, with marked structural differences across primate taxa, particularly for humans and chimpanzees, which exhibited unique patterns of large motifs of dinucleotide A+T repeats upstream of the OXTR 5' UTR. In addition, we observed a large number of amino acid substitutions in the OXTR CDS region among New World primate taxa that distinguish them from Old World primates. Furthermore, primate taxa traditionally defined as socially monogamous (e.g., gibbons, owl monkeys, titi monkeys, and saki monkeys) all exhibited different amino acid motifs for their respective OXTR protein coding sequences. These findings support the notion that monogamy has evolved independently in Old World and New World primates, and that it has done so through different molecular mechanisms, not exclusively through the oxytocin pathway.

  15. Genetic variation in the oxytocin receptor gene is associated with a social phenotype in autism spectrum disorders.

    PubMed

    Harrison, Ashley J; Gamsiz, Ece D; Berkowitz, Isaac C; Nagpal, Shailender; Jerskey, Beth A

    2015-12-01

    Oxytocin regulates social behavior in animal models. Research supports an association between genetic variation in the oxytocin receptor gene (OXTR) and autism spectrum disorders (ASD). In this study, we examine the association between the OXTR gene and a specific social phenotype within ASD. This genotype-phenotype investigation may provide insight into how OXTR conveys risk for social impairment. The current study investigated 10 SNPS in the OXTR gene that have been previously shown to be associated with ASD. We examine the association of these SNPs with both a social phenotype and a repetitive behavior phenotype comprised of behaviors commonly impaired in ASD in the Simons simplex collection (SSC). Using a large sample to examine the association between OXTR and ASD (n = range: 485-1002), we find evidence to support a relation between two OXTR SNPs and the examined social phenotype among children diagnosed with ASD. Greater impairment on the social responsiveness scale standardized total score and on several subdomains was observed among individuals with one or more copies of the minor frequency allele in both rs7632287 and rs237884. Linkage disequilibrium (LD) mapping suggests that these two SNPs are in LD within and overlapping the 3' untranslated region (3'-UTR) of the OXTR gene. These two SNPs were also associated with greater impairment on the repetitive behavior scale. Results of this study indicate that social impairment and repetitive behaviors in ASD are associated with genomic variation in the 3'UTR of the OXTR gene. These variants may be linked to an allele that alters stability of the mRNA message although further work is necessary to test this hypothesis.

  16. CB2 Cannabinoid Receptors Contribute to Bacterial Invasion and Mortality in Polymicrobial Sepsis

    PubMed Central

    Csóka, Balázs; Németh, Zoltán H.; Mukhopadhyay, Partha; Spolarics, Zoltán; Rajesh, Mohanraj; Federici, Stephanie; Deitch, Edwin A.; Bátkai, Sándor; Pacher, Pál; Haskó, György

    2009-01-01

    Background Sepsis is a major healthcare problem and current estimates suggest that the incidence of sepsis is approximately 750,000 annually. Sepsis is caused by an inability of the immune system to eliminate invading pathogens. It was recently proposed that endogenous mediators produced during sepsis can contribute to the immune dysfunction that is observed in sepsis. Endocannabinoids that are produced excessively in sepsis are potential factors leading to immune dysfunction, because they suppress immune cell function by binding to G-protein-coupled CB2 receptors on immune cells. Here we examined the role of CB2 receptors in regulating the host's response to sepsis. Methods and Findings The role of CB2 receptors was studied by subjecting CB2 receptor wild-type and knockout mice to bacterial sepsis induced by cecal ligation and puncture. We report that CB2 receptor inactivation by knockout decreases sepsis-induced mortality, and bacterial translocation into the bloodstream of septic animals. Furthermore, CB2 receptor inactivation decreases kidney and muscle injury, suppresses splenic nuclear factor (NF)-κB activation, and diminishes the production of IL-10, IL-6 and MIP-2. Finally, CB2 receptor deficiency prevents apoptosis in lymphoid organs and augments the number of CD11b+ and CD19+ cells during CLP. Conclusions Taken together, our results establish for the first time that CB2 receptors are important contributors to septic immune dysfunction and mortality, indicating that CB2 receptors may be therapeutically targeted for the benefit of patients suffering from sepsis. PMID:19641602

  17. Contribution of brain serotonin subtype 1B receptors in levodopa-induced motor complications.

    PubMed

    Morin, Nicolas; Morissette, Marc; Grégoire, Laurent; Rajput, Alex; Rajput, Ali H; Di Paolo, Thérèse

    2015-12-01

    L-DOPA-induced dyskinesias (LID) are abnormal involuntary movements limiting the chronic use of L-DOPA, the main pharmacological treatment of Parkinson's disease. Serotonin receptors are implicated in the development of LID and modulation of basal ganglia 5-HT1B receptors is a potential therapeutic alternative in Parkinson's disease. In the present study, we used receptor-binding autoradiography of the 5-HT1B-selective radioligand [3H]GR125743 to investigate possible contributions of changes in ligand binding of this receptor in LID in post-mortem brain specimens from Parkinson's disease patients (n=14) and control subjects (n=11), and from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys treated with saline (n=5), L-DOPA (n=4) or L-DOPA+2-methyl-6-(phenylethynyl)pyridine (MPEP) (n=5), and control monkeys (n=4). MPEP is the prototypal metabotropic glutamate 5 (mGlu5) receptor antagonist and has been shown to reduce the development of LID in these monkeys in a chronic treatment of one month. [3H]GR125743 specific binding to striatal and pallidal 5-HT1B receptors respectively were only increased in L-DOPA-treated MPTP monkeys (dyskinetic monkeys) as compared to controls, saline and L-DOPA+MPEP MPTP monkeys; dyskinesias scores correlated positively with this binding. Parkinson's disease patients with motor complications (L-DOPA-induced dyskinesias and wearing-off) had higher [3H]GR125743 specific binding compared to those without motor complications and controls in the basal ganglia. Reduction of motor complications was associated with normal striatal 5-HT1B receptors, suggesting the potential of this receptor for the management of motor complications in Parkinson's disease.

  18. Bicarbonate contributes to GABAA receptor-mediated neuronal excitation in surgically resected human hypothalamic hamartomas.

    PubMed

    Kim, Do-Young; Fenoglio, Kristina A; Kerrigan, John F; Rho, Jong M

    2009-01-01

    The role of bicarbonate (HCO(3)(-)) in GABA(A) receptor-mediated depolarization of human hypothalamic hamartoma (HH) neurons was investigated using cellular electrophysiological and calcium imaging techniques. Activation of GABA(A) receptors with muscimol (30 microM) provoked neuronal excitation in over 70% of large (18-22 microM) HH neurons in HCO(3)(-) buffer. Subsequent perfusion of HCO(3)(-)-free HEPES buffer produced partial suppression of muscimol-induced excitation. Additionally, 53% of large HH neurons under HCO(3)(-)-free conditions exhibited reduced intracellular calcium accumulation by muscimol. These results suggest that HCO(3)(-) efflux through GABA(A) receptors on a subpopulation of large HH neurons may contribute to membrane depolarization and subsequent activation of L-type calcium channels.

  19. Mineralocorticoid Receptor Activation Contributes to the Supine Hypertension of Autonomic Failure.

    PubMed

    Arnold, Amy C; Okamoto, Luis E; Gamboa, Alfredo; Black, Bonnie K; Raj, Satish R; Elijovich, Fernando; Robertson, David; Shibao, Cyndya A; Biaggioni, Italo

    2016-02-01

    Primary autonomic failure is characterized by disabling orthostatic hypotension, but at least half of these patients have paradoxical supine hypertension. Renin-angiotensin mechanisms were not initially thought to contribute to this hypertension because plasma renin activity is often undetectable in autonomic failure. Plasma aldosterone levels are normal, however, and we recently showed that plasma angiotensin II is elevated and acts at AT1 (angiotensin type 1) receptors to contribute to hypertension in these patients. Because aldosterone and angiotensin II can also bind mineralocorticoid receptors to elevate blood pressure, we hypothesized that mineralocorticoid receptor activation plays a role in the hypertension of autonomic failure. To test this hypothesis, we determined the acute effects of the mineralocorticoid receptor antagonist eplerenone (50 mg, oral) versus placebo on supine blood pressure in a randomized, double-blind, crossover study. Medications were given at 8:00 pm with blood pressure recorded every 2 hours for 12 hours. Ten primary autonomic failure patients with supine hypertension completed this study (7 pure autonomic failure, 2 multiple system atrophy, 1 parkinson's disease; 7 male; 70±2 years of age). Eplerenone maximally reduced supine systolic blood pressure by 32±6 mm Hg at 8 hours after administration (versus 8±10 mm Hg placebo, P=0.016), with no effect on nocturia (12-hour urine volume: 985±134 mL placebo versus 931±94 mL eplerenone, P=0.492; nocturnal weight loss: -1.19±0.15 kg placebo versus -1.18±0.15 kg eplerenone, P=0.766). These findings suggest that inappropriate mineralocorticoid receptor activation contributes to the hypertension of autonomic failure, likely independent of canonical mineralocorticoid effects, and provides rationale for use of eplerenone in these patients.

  20. Activation by SLAM Family Receptors Contributes to NK Cell Mediated "Missing-Self" Recognition.

    PubMed

    Alari-Pahissa, Elisenda; Grandclément, Camille; Jeevan-Raj, Beena; Leclercq, Georges; Veillette, André; Held, Werner

    2016-01-01

    Natural Killer (NK) cells attack normal hematopoietic cells that do not express inhibitory MHC class I (MHC-I) molecules, but the ligands that activate NK cells remain incompletely defined. Here we show that the expression of the Signaling Lymphocyte Activation Molecule (SLAM) family members CD48 and Ly9 (CD229) by MHC-I-deficient tumor cells significantly contributes to NK cell activation. When NK cells develop in the presence of T cells or B cells that lack inhibitory MHC-I but express activating CD48 and Ly9 ligands, the NK cells' ability to respond to MHC-I-deficient tumor cells is severely compromised. In this situation, NK cells express normal levels of the corresponding activation receptors 2B4 (CD244) and Ly9 but these receptors are non-functional. This provides a partial explanation for the tolerance of NK cells to MHC-I-deficient cells in vivo. Activating signaling via 2B4 is restored when MHC-I-deficient T cells are removed, indicating that interactions with MHC-I-deficient T cells dominantly, but not permanently, impair the function of the 2B4 NK cell activation receptor. These data identify an important role of SLAM family receptors for NK cell mediated "missing-self" reactivity and suggest that NK cell tolerance in MHC-I mosaic mice is in part explained by an acquired dysfunction of SLAM family receptors.

  1. Activation of Lysophosphatidic Acid Receptor Type 1 Contributes to Pathophysiology of Spinal Cord Injury

    PubMed Central

    Santos-Nogueira, Eva; López-Serrano, Clara; Hernández, Joaquim; Lago, Natalia; Astudillo, Alma M.; Balsinde, Jesús; Estivill-Torrús, Guillermo; de Fonseca, Fernando Rodriguez; Chun, Jerold

    2015-01-01

    Lysophosphatidic acid (LPA) is an extracellular lipid mediator involved in many physiological functions that signals through six known G-protein-coupled receptors (LPA1–LPA6). A wide range of LPA effects have been identified in the CNS, including neural progenitor cell physiology, astrocyte and microglia activation, neuronal cell death, axonal retraction, and development of neuropathic pain. However, little is known about the involvement of LPA in CNS pathologies. Herein, we demonstrate for the first time that LPA signaling via LPA1 contributes to secondary damage after spinal cord injury. LPA levels increase in the contused spinal cord parenchyma during the first 14 d. To model this potential contribution of LPA in the spinal cord, we injected LPA into the normal spinal cord, revealing that LPA induces microglia/macrophage activation and demyelination. Use of a selective LPA1 antagonist or mice lacking LPA1 linked receptor-mediated signaling to demyelination, which was in part mediated by microglia. Finally, we demonstrate that selective blockade of LPA1 after spinal cord injury results in reduced demyelination and improvement in locomotor recovery. Overall, these results support LPA–LPA1 signaling as a novel pathway that contributes to secondary damage after spinal cord contusion in mice and suggest that LPA1 antagonism might be useful for the treatment of acute spinal cord injury. SIGNIFICANCE STATEMENT This study reveals that LPA signaling via LPA receptor type 1 activation causes demyelination and functional deficits after spinal cord injury. PMID:26180199

  2. Common variant in OXTR predicts growth in positive emotions from loving-kindness training.

    PubMed

    Isgett, Suzannah F; Algoe, Sara B; Boulton, Aaron J; Way, Baldwin M; Fredrickson, Barbara L

    2016-11-01

    Ample research suggests that social connection reliably generates positive emotions. Oxytocin, a neuropeptide implicated in social cognition and behavior, is one biological mechanism that may influence an individual's capacity to extract positive emotions from social contexts. Because variation in certain genes may indicate underlying neurobiological differences, we tested whether several SNPs in two genes related to oxytocin signaling would show effects on positive emotions that were context-specific, depending on sociality. For six weeks, a sample of mid-life adults (N=122) participated in either socially-focused loving-kindness training or mindfulness training. During this timespan they reported their positive emotions daily. Five SNPs within OXTR and CD38 were assayed, and each was tested for its individual effect on daily emotions. The hypothesized three-way interaction between time, training type, and genetic variability emerged: Individuals homozygous for the G allele of OXTR rs1042778 experienced gains in daily positive emotions from loving-kindness training, whereas individuals with the T allele did not experience gains in positive emotions with either training. These findings are among the first to show how genetic differences in oxytocin signaling may influence an individual's capacity to experience positive emotions as a result of a socially-focused intervention.

  3. Prevention of Early Substance Use Mediates, and Variation at SLC6A4 Moderates, SAAF Intervention Effects on OXTR Methylation.

    PubMed

    Beach, Steven R H; Lei, Man Kit; Brody, Gene H; Philibert, Robert A

    2016-09-21

    The Strong African American Family (SAAF) program has been shown to have a variety of short and long-term benefits for participating youth and families. However, biological mechanisms potentially influencing long-term effects on resilience in young adulthood have not been examined. In the current investigation, we examine the effects of SAAF on methylation of the OXTR gene in young adulthood, focusing on a regulatory region previously identified to be both responsive to stress and implicated in resilience. Using the subsample of participants from the original study for whom methylation data was available (N = 388), we replicated the previously reported G × E effect on prevention of early substance use and then examined whether there would also be a moderated effect on OXTR methylation in early adulthood, with "s" allele carriers, but not "LL" participants, showing a significant indirect effect of SAAF on OXTR methylation. Results suggest that for susceptible youth (i.e., "s" allele carriers), preventive intervention may "get under the skin," in a manner potentially beneficial for long-term outcomes. Implications for examination of OXTR methylation in future prevention research are discussed.

  4. Bradykinin B2 receptor contributes to the exaggerated muscle mechanoreflex in rats with femoral artery occlusion

    PubMed Central

    Lu, Jian; Xing, Jihong

    2013-01-01

    Static muscle contraction activates the exercise pressor reflex, which in turn increases sympathetic nerve activity (SNA) and blood pressure (BP). Bradykinin (BK) is considered as a muscle metabolite responsible for modulation of the sympathetic and cardiovascular responses to muscle contraction. Prior studies have suggested that kinin B2 receptor mediates the effects of BK on the reflex SNA and BP responses during stimulation of skeletal muscle afferents. In patients with peripheral artery disease and a rat model with femoral artery ligation, amplified SNA and BP responses to static exercise were observed. This dysfunction of the exercise pressor reflex has previously been shown to be mediated, in part, by muscle mechanoreflex overactivity. Thus, in this report, we determined whether kinin B2 receptor contributes to the augmented mechanoreflex activity in rats with 24 h of femoral artery occlusion. First, Western blot analysis was used to examine protein expression of B2 receptors in dorsal root ganglion tissues of control limbs and ligated limbs. Our data show that B2 receptor displays significant overexpression in ligated limbs as compared with control limbs (optical density: 0.94 ± 0.02 in control and 1.87 ± 0.08 after ligation, P < 0.05 vs. control; n = 6 in each group). Second, mechanoreflex was evoked by muscle stretch and the reflex renal SNA (RSNA) and mean arterial pressure (MAP) responses to muscle stretch were examined after HOE-140, a B2 receptors blocker, was injected into the arterial blood supply of the hindlimb muscles. The results demonstrate that the stretch-evoked reflex responses were attenuated by administration of HOE-140 in control rats and ligated rats; however, the attenuating effects of HOE-140 were significantly greater in ligated rats, i.e., after 5 μg/kg of HOE-140 RSNA and MAP responses evoked by 0.5 kg of muscle tension were attenuated by 43% and 25% in control vs. 54% and 34% in ligation (P < 0.05 vs. control group; n = 11 in

  5. Contribution of the P2Y12 receptor-mediated pathway to platelet hyperreactivity in hypercholesterolemia

    PubMed Central

    Nagy, Béla; Jin, Jianguo; Ashby, Barrie; Reilly, Michael P.; Kunapuli, Satya P.

    2011-01-01

    Summary Background In hypercholesterolemia, platelets demonstrate increased reactivity and promote the development of cardiovascular disease. Objective This study was carried out to investigate the contribution of the ADP receptor P2Y12-mediated pathway in platelet hyperreactivity due to hypercholesterolemia. Methods Low-density lipoprotein receptor deficient mice and C57Bl/6 wild type mice were fed on normal chow and high-fat (Western or Paigen) diets for 8 weeks to generate differently elevated cholesterol levels. P2Y12 receptor induced functional responses via Gi signaling were studied ex vivo when washed murine platelets were activated by 2MeSADP and PAR4 agonist AYPGKF in the presence and absence of indomethacin. Platelet aggregation, secretion, αIIbβ3 receptor activation and the phosphorylation of extracellular signal-regulated protein kinase (ERK) and Akt were analyzed. Results Plasma cholesterol levels ranged from 69±10 to 1011±185 mg/dl depending on diet in mice with different genotypes. Agonist-dependent aggregation, dense and α-granule secretion and JON/A binding were gradually and significantly (P < 0.05) augmented at low agonist concentration in correlation with the increasing plasma cholesterol levels even if elevated thromboxane generation was blocked. These functional responses were induced via increased level of Gi mediated ERK and Akt phosphorylation in hypercholesterolemic mice versus normocholesterolemic animals. In addition, blocking of the P2Y12 receptor by AR-C69931MX (Cangrelor) resulted in strongly reduced platelet aggregation in mice with elevated cholesterol levels compared to normocholesterolemic controls. Conclusions These data revealed that the P2Y12 receptor pathway was substantially involved in platelet hyperreactivity associated with mild and severe hypercholesterolemia. PMID:21261805

  6. Contribution of renal purinergic receptors to renal vasoconstriction in angiotensin II-induced hypertensive rats.

    PubMed

    Franco, Martha; Bautista, Rocio; Tapia, Edilia; Soto, Virgilia; Santamaría, José; Osorio, Horacio; Pacheco, Ursino; Sánchez-Lozada, L Gabriela; Kobori, Hiroyuki; Navar, L Gabriel

    2011-06-01

    To investigate the participation of purinergic P2 receptors in the regulation of renal function in ANG II-dependent hypertension, renal and glomerular hemodynamics were evaluated in chronic ANG II-infused (14 days) and Sham rats during acute blockade of P2 receptors with PPADS. In addition, P2X1 and P2Y1 protein and mRNA expression were compared in ANG II-infused and Sham rats. Chronic ANG II-infused rats exhibited increased afferent and efferent arteriolar resistances and reductions in glomerular blood flow, glomerular filtration rate (GFR), single-nephron GFR (SNGFR), and glomerular ultrafiltration coefficient. PPADS restored afferent and efferent resistances as well as glomerular blood flow and SNGFR, but did not ameliorate the elevated arterial blood pressure. In Sham rats, PPADS increased afferent and efferent arteriolar resistances and reduced GFR and SNGFR. Since purinergic blockade may influence nitric oxide (NO) release, we evaluated the role of NO in the response to PPADS. Acute blockade with N(ω)-nitro-l-arginine methyl ester (l-NAME) reversed the vasodilatory effects of PPADS and reduced urinary nitrate excretion (NO(2)(-)/NO(3)(-)) in ANG II-infused rats, indicating a NO-mediated vasodilation during PPADS treatment. In Sham rats, PPADS induced renal vasoconstriction which was not modified by l-NAME, suggesting blockade of a P2X receptor subtype linked to the NO pathway; the response was similar to that obtained with l-NAME alone. P2X1 receptor expression in the renal cortex was increased by chronic ANG II infusion, but there were no changes in P2Y1 receptor abundance. These findings indicate that there is an enhanced P2 receptor-mediated vasoconstriction of afferent and efferent arterioles in chronic ANG II-infused rats, which contributes to the increased renal vascular resistance observed in ANG II-dependent hypertension.

  7. Contribution of valine 7' of TMD2 to gating of neuronal alpha3 receptor subtypes.

    PubMed

    Nieves-Cintrón, Madeline; Caballero-Rivera, Daniel; Navedo, Manuel F; Lasalde-Dominicci, José A

    2006-12-01

    The second transmembrane domain (TMD2) of the Cys-loop family of ligand-gated ion channels forms the channel pore. The functional role of the amino acid residues contributing to the channel pore in neuronal nicotinic alpha3 receptors is not well understood. We characterized the contribution of TMD2 position V7' to channel gating in neuronal nicotinic alpha3 receptors. Site-directed mutagenesis was used to substitute position alpha3 (V7') with four different amino acids (A, F, S, or Y) and coexpressed each mutant subunit with wild-type (WT) beta2 or beta4 subunits in Xenopus oocytes. Whole-cell voltage clamp experiments show that substitution for an alanine, serine, or phenylalanine decreased by 2.3-6.2-fold the ACh-EC(50) for alpha3beta2 and alpha3beta4 receptor subtypes. Interestingly, mutation V7'Y did not produce a significant change in ACh-EC(50) when coexpressed with the beta2 subunit but showed a significant approximately two-fold increase with beta4. Similar responses were obtained with nicotine as the agonist. The antagonist sensitivity of the mutant channels was assessed by using dihydro-beta-erythroidine (DHbetaE) and methyllycaconitine (MLA). The apparent potency of DHbetaE as an antagonist increased by approximately 3.7- and 11-fold for the alpha3beta2 V7'S and V7'F mutants, respectively, whereas no evident changes in antagonist potency were observed for the V7'A and V7'Y mutants. The V7'S and V7'F mutations increase MLA antagonist potency for the alpha3beta4 receptor by approximately 6.2- and approximately 9.3-fold, respectively. The V7'A mutation selectively increases the MLA antagonist potency for the alpha3beta4 receptor by approximately 18.7-fold. These results indicate that position V7' contributes to channel gating kinetics and pharmacology of the neuronal nicotinic alpha3 receptors.

  8. Evaluation on Potential Contributions of Protease Activated Receptors Related Mediators in Allergic Inflammation

    PubMed Central

    Zhang, Huiyun; Zeng, Xiaoning; He, Shaoheng

    2014-01-01

    Protease activated receptors (PARs) have been recognized as a distinctive four-member family of seven transmembrane G protein-coupled receptors (GPCRs) that can be cleaved by certain serine proteases. In recent years, there has been considerable interest in the role of PARs in allergic inflammation, the fundamental pathologic changes of allergy, but the potential roles of PARs in allergy remain obscure. Since many of these proteases are produced and actively involved in the pathologic process of inflammation including exudation of plasma components, inflammatory cell infiltration, and tissue damage and repair, PARs appear to make important contribution to allergy. The aim of the present review is to summarize the expression of PARs in inflammatory and structural cells, the influence of agonists or antagonists of PARs on cell behavior, and the involvement of PARs in allergic disorders, which will help us to better understand the roles of serine proteases and PARs in allergy. PMID:24876677

  9. Contribution of toll-like receptor signaling pathways to breast tumorigenesis and treatment

    PubMed Central

    Kidd, La Creis R; Rogers, Erica N; Yeyeodu, Susan T; Jones, Dominique Z; Kimbro, K Sean

    2013-01-01

    Mounting evidence indicates that anomalies in the inflammatory and immune response pathways are essential to tumorigenesis. However, tumor-based innate immunity initiated by transformed breast epithelia tissues has received much less attention. This review summarizes published reports on the role of the toll-like receptor signaling pathway on breast cancer risk, disease progression, survival, and disease recurrence. Specifically, we discuss the underlying biological mechanisms that contribute to the tumorigenic and/or anti-tumorigenic properties of toll-like receptors and their associated agonists in relation to breast tumorigenesis and cancer treatment. Further, we use results from preclinical, clinical, and population-based studies as prompts for the exploration of new and more effective breast cancer therapies. As the knowledge base of innate immunity’s involvement in breast cancer progression increases, current and new immune-modifying strategies will be refined to effectively treat breast cancer. PMID:24648757

  10. 5-HT1A and 5-HT7 receptors contribute to lurasidone-induced dopamine efflux.

    PubMed

    Huang, Mei; Horiguchi, Masakuni; Felix, Anna R; Meltzer, Herbert Y

    2012-05-09

    Lurasidone is a novel, atypical antipsychotic drug with serotonin [5-hydroxytryptamine (5-HT)]2A, 5-HT7, dopamine (DA) D2 antagonist, and 5-HT1A receptor partial agonist properties. The ability of lurasidone to reverse the effects of subchronic administration phencyclidine, to impair novel object recognition in rats, an animal model of cognitive impairment in schizophrenia, is dependent, in part, on its 5-HT1A agonist and 5-HT7 receptor antagonist properties. We tested whether 5-HT1A partial agonism or 5-HT7 antagonism, or both, contributed to the ability of lurasidone to enhance cortical and hippocampal DA efflux, which may be related to its ability to improve cognition. Here, we report that lurasidone, 0.25 and 0.5, but not 0.1 mg/kg, subcutaneously, significantly increased DA efflux in the prefrontal cortex and hippocampus in a dose-dependent manner. Lurasidone, 0.5 mg/kg, also produced a smaller increase in DA efflux in the nucleus accumbens. Pretreatment with the 5-HT1A receptor antagonist, WAY100635 (0.2 mg/kg, subcutaneously), partially blocked the lurasidone-induced cortical and hippocampal DA efflux. Further, subeffective doses of the 5-HT1A receptor agonist, tandospirone (0.2 mg/kg), or the 5-HT7 antagonist, SB269970 (0.3 mg/kg), potentiated the ability of a subeffective dose of lurasidone (0.1 mg/kg) to increase DA efflux in the prefrontal cortex. These findings suggest that the effects of lurasidone on the prefrontal cortex and hippocampus, DA efflux are dependent, at least partially, on its 5-HT1A agonist and 5-HT7 antagonist properties and may contribute to its efficacy to reverse the effects of subchronic phencyclidine treatment and improve schizophrenia.

  11. Topoisomerase 2 Alpha Cooperates with Androgen Receptor to Contribute to Prostate Cancer Progression

    PubMed Central

    Schaefer-Klein, J. L.; Murphy, Stephen J.; Johnson, Sarah H.; Vasmatzis, George; Kovtun, Irina V.

    2015-01-01

    Overexpression of TOP2A is associated with risk of systemic progression in prostate cancer patients, and higher levels of TOP2A were found in hormone-resistant cases. To elucidate the mechanism by which high levels of TOP2A contribute to tumor progression we generated TOP2A overexpressing prostate cancer cell lines. We show that TOP2A promotes tumor aggressiveness by inducing chromosomal rearrangements of genes that contribute to a more invasive phenotype. Anti-androgen treatment alone was ineffective in killing TOP2A overexpressing cells due to activation of an androgen receptor network. TOP2A poisons killed tumor cells more efficiently early in the progression course, while at later stages they provided greater benefit when combined with anti-androgen therapy. Mechanistically, we find that TOP2A enhances androgen signaling by facilitating transcription of androgen responsive genes, thereby promoting tumor cell growth. These studies revealed a relationship between TOP2A and androgen receptor signaling pathway that contributes to prostate cancer progression and confers sensitivity to treatments. PMID:26560244

  12. Subunit Interfaces Contribute Differently to Activation and Allosteric Modulation of Neuronal Nicotinic Acetylcholine Receptors

    PubMed Central

    Short, Caitlin A.; Cao, Angela T.; Wingfield, Molly A.; Doers, Matthew E.; Jobe, Emily M.; Wang, Nan; Levandoski, Mark M.

    2015-01-01

    Neuronal nicotinic acetylcholine receptors (nAChRs) are widely distributed in the nervous system and are implicated in many normal and pathological processes. The structural determinants of allostery in nAChRs are not well understood. One class of nAChR allosteric modulators, including the small molecule morantel (Mor), acts from a site that is structurally homologous to the canonical agonist site but exists in the β(+)/α(–) subunit interface. We hypothesized that all nAChR subunits move with respect to each other during channel activation and allosteric modulation. We therefore studied five pairs of residues predicted to span the interfaces of α3β2 receptors, one at the agonist interface and four at the modulator interface. Substituting cysteines in these positions, we used disulfide trapping to perturb receptor function. The pair α3Y168-β2D190, involving the C loop region of the β2 subunit, mediates modulation and agonist activation, because evoked currents were reduced up to 50% following oxidation (H2O2) treatment. The pair α3S125-β2Q39, below the canonical site, is also involved in channel activation, in accord with previous studies of the muscle-type receptor; however, the pair is differentially sensitive to ACh activation and Mor modulation (currents decreased 60% and 80%, respectively). The pairs α3Q37-β2A127 and α3E173-β2R46, both in the non-canonical interface, showed increased currents following oxidation, suggesting that subunit movements are not symmetrical. Together, our results from disulfide trapping and further mutation analysis indicate that subunit interface movement is important for allosteric modulation of nAChRs, but that the two types of interfaces contribute unequally to receptor activation. PMID:25486620

  13. Differential contribution of mineralocorticoid and glucocorticoid receptors to memory formation during sleep.

    PubMed

    Groch, Sabine; Wilhelm, Ines; Lange, Tanja; Born, Jan

    2013-12-01

    Corticosteroids are known to modulate the consolidation of memories during sleep, specifically in the hippocampus-dependent declarative memory system. However, effects of the major human corticosteroid cortisol are conveyed via two different receptors, i.e., mineralocorticoid (MRs) and glucocorticoid receptors (GRs) whose specific contributions to memory consolidation are unclear. Whereas a shift in the balance between MR and GR activation toward predominant GR activation has been found to impair sleep-dependent consolidation of declarative memories, the effect of predominant MR activation is not well characterized. Here, we examined differential corticosteroid receptor contributions to memory consolidation during post-learning sleep in two placebo-controlled double-blind studies in humans, by comparing the effects of the selective MR agonist fludrocortisone (0.2 mg, orally, Study 1) and of hydrocortisone (22 mg, intravenously, Study 2) with strong binding affinity to both MR and GR. We hypothesized increased activation of MRs during sleep to enhance declarative memory consolidation, but the joint MR/GR activation to impair it. Participants (16 men in each study) learned a declarative (word pair associates) and a procedural task (mirror tracing) before a 7-h period of nocturnal retention sleep, with the substances administered before sleep (Study 1) and during sleep (Study 2), respectively. As hypothesized, retention of word pairs, but not of mirror tracing skill, was selectively enhanced by the MR agonist fludrocortisone. An impairing effect of hydrocortisone on word pair retention remained non-significant possibly reflecting that hydrocortisone administration failed to establish robust predominance of GR activation. Our results show that predominant MR activation benefits declarative memory consolidation presumably by enhancing the sleep-dependent reactivation of hippocampal memories and resultant synaptic plastic processes. The effect is counteracted by

  14. Type 3 muscarinic receptors contribute to intestinal mucosal homeostasis and clearance of nippostrongylus brasiliensis through induction of Th2 cytokines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite increased appreciation for the role of nicotinic receptors in the modulation of and response to inflammation, the contribution of muscarinic receptors to mucosal homeostasis, clearance of enteric pathogens, and modulation of immune cell function remains relatively undefined. Uninfected and N...

  15. Genetic Diversity in Oxytocin Ligands and Receptors in New World Monkeys

    PubMed Central

    Ren, Dongren; Lu, Guoqing; Moriyama, Hideaki; Mustoe, Aaryn C.; Harrison, Emily B.; French, Jeffrey A.

    2015-01-01

    Oxytocin (OXT) is an important neurohypophyseal hormone that influences wide spectrum of reproductive and social processes. Eutherian mammals possess a highly conserved sequence of OXT (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly). However, in this study, we sequenced the coding region for OXT in 22 species covering all New World monkeys (NWM) genera and clades, and characterize five OXT variants, including consensus mammalian Leu8-OXT, major variant Pro8-OXT, and three previously unreported variants: Ala8-OXT, Thr8-OXT, and Phe2-OXT. Pro8-OXT shows clear structural and physicochemical differences from Leu8-OXT. We report multiple predicted amino acid substitutions in the G protein-coupled OXT receptor (OXTR), especially in the critical N-terminus, which is crucial for OXT recognition and binding. Genera with same Pro8-OXT tend to cluster together on a phylogenetic tree based on OXTR sequence, and we demonstrate significant coevolution between OXT and OXTR. NWM species are characterized by high incidence of social monogamy, and we document an association between OXTR phylogeny and social monogamy. Our results demonstrate remarkable genetic diversity in the NWM OXT/OXTR system, which can provide a foundation for molecular, pharmacological, and behavioral studies of the role of OXT signaling in regulating complex social phenotypes. PMID:25938568

  16. DNA methylation of the oxytocin receptor gene predicts neural response to ambiguous social stimuli

    PubMed Central

    Jack, Allison; Connelly, Jessica J.; Morris, James P.

    2012-01-01

    Oxytocin and its receptor (OXTR) play an important role in a variety of social perceptual and affiliative processes. Individual variability in social information processing likely has a strong heritable component, and as such, many investigations have established an association between common genetic variants of OXTR and variability in the social phenotype. However, to date, these investigations have primarily focused only on changes in the sequence of DNA without considering the role of epigenetic factors. DNA methylation is an epigenetic mechanism by which cells control transcription through modification of chromatin structure. DNA methylation of OXTR decreases expression of the gene and high levels of methylation have been associated with autism spectrum disorders (ASD). This link between epigenetic variability and social phenotype allows for the possibility that social processes are under epigenetic control. We hypothesized that the level of DNA methylation of OXTR would predict individual variability in social perception. Using the brain's sensitivity to displays of animacy as a neural endophenotype of social perception, we found significant associations between the degree of OXTR methylation and brain activity evoked by the perception of animacy. Our results suggest that consideration of DNA methylation may substantially improve our ability to explain individual differences in imaging genetic association studies. PMID:23087634

  17. Endocannabinoid receptor deficiency affects maternal care and alters the dam's hippocampal oxytocin receptor and brain-derived neurotrophic factor expression.

    PubMed

    Schechter, M; Weller, A; Pittel, Z; Gross, M; Zimmer, A; Pinhasov, A

    2013-10-01

    Maternal care is the newborn's first experience of social interaction, and this influences infant survival, development and social competences throughout life. We recently found that postpartum blocking of the endocannabinoid receptor-1 (CB1R) altered maternal behaviour. In the present study, maternal care was assessed by the time taken to retrieve pups, pups' ultrasonic vocalisations (USVs) and pup body weight, comparing CB1R deleted (CB1R KO) versus wild-type (WT) mice. After culling on postpartum day 8, hippocampal expression of oxytocin receptor (OXTR), brain-derived neurotrophic factor (BDNF) and stress-mediating factors were evaluated in CB1R KO and WT dams. Comparisons were also performed with nulliparous (NP) CB1R KO and WT mice. Compared to WT, CB1R KO dams were slower to retrieve their pups. Although the body weight of the KO pups did not differ from the weight of WT pups, they emitted fewer USVs. This impairment of the dam-pup relationship correlated with a significant reduction of OXTR mRNA and protein levels among CB1R KO dams compared to WT dams. Furthermore, WT dams exhibited elevated OXTR mRNA expression, as well as increased levels of mineralocorticoid and glucocorticoid receptors, compared to WT NP mice. By contrast, CB1R KO dams showed no such elevation of OXTR expression, alongside lower BDNF and mineralocorticoid receptors, as well as elevated corticotrophin-releasing hormone mRNA levels, when compared to CB1R KO NP. Thus, it appears that the disruption of endocannabinoid signalling by CB1R deletion alters expression of the OXTR, apparently leading to deleterious effects upon maternal behaviour.

  18. Energetic Contributions to Channel Gating of Residues in the Muscle Nicotinic Receptor β1 Subunit

    PubMed Central

    Akk, Gustav; Eaton, Megan; Li, Ping; Zheng, Steven; Lo, Joshua; Steinbach, Joe Henry

    2013-01-01

    In the pentameric ligand-gated ion channel family, transmitter binds in the extracellular domain and conformational changes result in channel opening in the transmembrane domain. In the muscle nicotinic receptor and other heteromeric members of the family one subunit does not contribute to the canonical agonist binding site for transmitter. A fundamental question is whether conformational changes occur in this subunit. We used records of single channel activity and rate-equilibrium free energy relationships to examine the β1 (non-ACh-binding) subunit of the muscle nicotinic receptor. Mutations to residues in the extracellular domain have minimal effects on the gating equilibrium constant. Positions in the channel lining (M2 transmembrane) domain contribute strongly and relatively late during gating. Positions thought to be important in other subunits in coupling the transmitter-binding to the channel domains have minimal effects on gating. We conclude that the conformational changes involved in channel gating propagate from the binding-site to the channel in the ACh-binding subunits and subsequently spread to the non-binding subunit. PMID:24194945

  19. Melanocortin 4 receptor mutations contribute to the adaptation of cavefish to nutrient-poor conditions

    PubMed Central

    Aspiras, Ariel C.; Rohner, Nicolas; Martineau, Brian; Borowsky, Richard L.; Tabin, Clifford J.

    2015-01-01

    Despite recent advances in the understanding of morphological evolution, the genetic underpinnings of behavioral and physiological evolution remain largely unknown. Here, we study the metabolic changes that evolved in independently derived populations of the Mexican cavefish, Astyanax mexicanus. A hallmark of cave environments is scarcity of food. Cavefish populations rely almost entirely on sporadic food input from outside of the caves. To survive under these conditions, cavefish have evolved a range of adaptations, including starvation resistance and binge eating when food becomes available. The use of these adaptive strategies differs among independently derived cave populations. Although all cavefish populations tested lose weight more slowly than their surface conspecifics during restricted rations, only a subset of cavefish populations consume more food than their surface counterparts. A candidate gene-based screen led to the identification of coding mutations in conserved residues of the melanocortin 4 receptor (MC4R) gene, contributing to the insatiable appetite found in some populations of cavefish. Intriguingly, one of the mutated residues has been shown to be linked to obesity in humans. We demonstrate that the allele results in both reduced maximal response and reduced basal activity of the receptor in vitro. We further validate in vivo that the mutated allele contributes to elevated appetite, growth, and starvation resistance. The allele appears to be fixed in cave populations in which the overeating phenotype is present. The presence of the same allele in multiple caves appears to be due to selection from standing genetic variation present in surface populations. PMID:26170297

  20. Glutamatergic receptor dysfunction in spinal cord contributes to the exaggerated exercise pressor reflex in heart failure

    PubMed Central

    Wang, Han-Jun; Cahoon, Rebecca; Cahoon, Edgar B.; Zheng, Hong; Patel, Kaushik P.

    2014-01-01

    Excitatory amino acids (e.g., glutamate) released by contraction-activated skeletal muscle afferents into the dorsal horn of the spinal cord initiate the central component of the exercise pressor reflex (EPR) in physiological conditions. However, the role of glutamate and glutamate receptors in mediating the exaggerated EPR in the chronic heart failure (CHF) state remains to be determined. In the present study, we performed microinjection of glutamate receptor antagonists into ipisilateral L4/L5 dorsal horns to investigate their effects on the pressor response to static contraction induced by stimulation of the peripheral end of L4/L5 ventral roots in decerebrate sham-operated (sham) and CHF rats. Microinjection of glutamate (10 mM, 100 nl) into the L4 or L5 dorsal horn caused a greater pressor response in CHF rats compared with sham rats. Furthermore, microinjection of either the broad-spectrum glutamate receptor antagonist kynurenate (10 mM, 100 nl) or the N-methyl-d-aspartate (NMDA) receptor antagonist dl-2-amino-5-phosphonovalerate (50 mM, 100 nl) or the non-NMDA-sensitive receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (5 mM, 100 nl) into L4/5 dorsal horns decreased the pressor response to static contraction in CHF rats to a greater extent than in sham rats. Molecular evidence showed that the protein expression of glutamate receptors (both non-NMDA and NMDA) was elevated in the dorsal horn of the lumbar spinal cord in CHF rats. In addition, data from microdialysis experiments demonstrated that although basal glutamate release at the dorsal horn at rest was similar between sham and CHF rats (225 ± 50 vs. 260 ± 63 nM in sham vs. CHF rats, n = 4, P > 0.05), CHF rats exhibit greater glutamate release into the dorsal horn during muscle contraction compared with sham rats (549 ± 60 vs. 980 ± 65 nM in sham vs. CHF rats, n = 4, P < 0.01). These data indicate that the spinal glutamate system contributes to the exaggerated EPR in the CHF state. PMID

  1. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila.

    PubMed

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca(2+), also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans.

  2. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila

    PubMed Central

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca2+, also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans. PMID:25158689

  3. Glutamate receptors in the nucleus tractus solitarius contribute to ventilatory acclimatization to hypoxia in rat

    PubMed Central

    Pamenter, Matthew E; Carr, J Austin; Go, Ariel; Fu, Zhenxing; Reid, Stephen G; Powell, Frank L

    2014-01-01

    When exposed to a hypoxic environment the body's first response is a reflex increase in ventilation, termed the hypoxic ventilatory response (HVR). With chronic sustained hypoxia (CSH), such as during acclimatization to high altitude, an additional time-dependent increase in ventilation occurs, which increases the HVR. This secondary increase persists after exposure to CSH and involves plasticity within the circuits in the central nervous system that control breathing. Currently these mechanisms of HVR plasticity are unknown and we hypothesized that they involve glutamatergic synapses in the nucleus tractus solitarius (NTS), where afferent endings from arterial chemoreceptors terminate. To test this, we treated rats held in normoxia (CON) or 10% O2 (CSH) for 7 days and measured ventilation in conscious, unrestrained animals before and after microinjecting glutamate receptor agonists and antagonists into the NTS. In normoxia, AMPA increased ventilation 25% and 50% in CON and CSH, respectively, while NMDA doubled ventilation in both groups (P < 0.05). Specific AMPA and NMDA receptor antagonists (NBQX and MK801, respectively) abolished these effects. MK801 significantly decreased the HVR in CON rats, and completely blocked the acute HVR in CSH rats but had no effect on ventilation in normoxia. NBQX decreased ventilation whenever it was increased relative to normoxic controls; i.e. acute hypoxia in CON and CSH, and normoxia in CSH. These results support our hypothesis that glutamate receptors in the NTS contribute to plasticity in the HVR with CSH. The mechanism underlying this synaptic plasticity is probably glutamate receptor modification, as in CSH rats the expression of phosphorylated NR1 and GluR1 proteins in the NTS increased 35% and 70%, respectively, relative to that in CON rats. PMID:24492841

  4. Glutamate receptors in the nucleus tractus solitarius contribute to ventilatory acclimatization to hypoxia in rat.

    PubMed

    Pamenter, Matthew E; Carr, J Austin; Go, Ariel; Fu, Zhenxing; Reid, Stephen G; Powell, Frank L

    2014-04-15

    When exposed to a hypoxic environment the body's first response is a reflex increase in ventilation, termed the hypoxic ventilatory response (HVR). With chronic sustained hypoxia (CSH), such as during acclimatization to high altitude, an additional time-dependent increase in ventilation occurs, which increases the HVR. This secondary increase persists after exposure to CSH and involves plasticity within the circuits in the central nervous system that control breathing. Currently these mechanisms of HVR plasticity are unknown and we hypothesized that they involve glutamatergic synapses in the nucleus tractus solitarius (NTS), where afferent endings from arterial chemoreceptors terminate. To test this, we treated rats held in normoxia (CON) or 10% O2 (CSH) for 7 days and measured ventilation in conscious, unrestrained animals before and after microinjecting glutamate receptor agonists and antagonists into the NTS. In normoxia, AMPA increased ventilation 25% and 50% in CON and CSH, respectively, while NMDA doubled ventilation in both groups (P < 0.05). Specific AMPA and NMDA receptor antagonists (NBQX and MK801, respectively) abolished these effects. MK801 significantly decreased the HVR in CON rats, and completely blocked the acute HVR in CSH rats but had no effect on ventilation in normoxia. NBQX decreased ventilation whenever it was increased relative to normoxic controls; i.e. acute hypoxia in CON and CSH, and normoxia in CSH. These results support our hypothesis that glutamate receptors in the NTS contribute to plasticity in the HVR with CSH. The mechanism underlying this synaptic plasticity is probably glutamate receptor modification, as in CSH rats the expression of phosphorylated NR1 and GluR1 proteins in the NTS increased 35% and 70%, respectively, relative to that in CON rats.

  5. Invariant Aspartic Acid in Muscle Nicotinic Receptor Contributes Selectively to the Kinetics of Agonist Binding

    PubMed Central

    Lee, Won Yong; Sine, Steven M.

    2004-01-01

    We examined functional contributions of interdomain contacts within the nicotinic receptor ligand binding site using single channel kinetic analyses, site-directed mutagenesis, and a homology model of the major extracellular region. At the principal face of the binding site, the invariant αD89 forms a highly conserved interdomain contact near αT148, αW149, and αT150. Patch-clamp recordings show that the mutation αD89N markedly slows acetylcholine (ACh) binding to receptors in the resting closed state, but does not affect rates of channel opening and closing. Neither αT148L, αT150A, nor mutations at both positions substantially affects the kinetics of receptor activation, showing that hydroxyl side chains at these positions are not hydrogen bond donors for the strong acceptor αD89. However substituting a negative charge at αT148, but not at αT150, counteracts the effect of αD89N, demonstrating that a negative charge in the region of interdomain contact confers rapid association of ACh. Interpreted within the structural framework of ACh binding protein and a homology model of the receptor ligand binding site, these results implicate main chain amide groups in the domain harboring αW149 as principal hydrogen bond donors for αD89. The specific effect of αD89N on ACh association suggests that interdomain hydrogen bonding positions αW149 for optimal interaction with ACh. PMID:15504901

  6. Spatial Distribution of the Cannabinoid Type 1 and Capsaicin Receptors May Contribute to the Complexity of Their Crosstalk

    PubMed Central

    Chen, Jie; Varga, Angelika; Selvarajah, Srikumaran; Jenes, Agnes; Dienes, Beatrix; Sousa-Valente, Joao; Kulik, Akos; Veress, Gabor; Brain, Susan D.; Baker, David; Urban, Laszlo; Mackie, Ken; Nagy, Istvan

    2016-01-01

    The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex, but largely unknown, functional interactions in a sub-population of primary sensory neurons (PSN). We report that PSN co-expressing CB1 receptor and TRPV1 form two distinct sub-populations based on their pharmacological properties, which could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin (COR neurons) or to both capsaicin and the endogenous TRPV1 and CB1 receptor ligand anandamide (ACR neurons). Blocking or deleting the CB1 receptor only reduces both anandamide- and capsaicin-evoked responses in ACR neurons. Deleting the CB1 receptor also reduces the proportion of ACR neurons without any effect on the overall number of capsaicin-responding cells. Regarding the distribution pattern of the two receptors, neurons express CB1 and TRPV1 receptors either isolated in low densities or in close proximity with medium/high densities. We suggest that spatial distribution of the CB1 receptor and TRPV1 contributes to the complexity of their functional interaction. PMID:27653550

  7. Spatial Distribution of the Cannabinoid Type 1 and Capsaicin Receptors May Contribute to the Complexity of Their Crosstalk.

    PubMed

    Chen, Jie; Varga, Angelika; Selvarajah, Srikumaran; Jenes, Agnes; Dienes, Beatrix; Sousa-Valente, Joao; Kulik, Akos; Veress, Gabor; Brain, Susan D; Baker, David; Urban, Laszlo; Mackie, Ken; Nagy, Istvan

    2016-09-22

    The cannabinoid type 1 (CB1) receptor and the capsaicin receptor (TRPV1) exhibit co-expression and complex, but largely unknown, functional interactions in a sub-population of primary sensory neurons (PSN). We report that PSN co-expressing CB1 receptor and TRPV1 form two distinct sub-populations based on their pharmacological properties, which could be due to the distribution pattern of the two receptors. Pharmacologically, neurons respond either only to capsaicin (COR neurons) or to both capsaicin and the endogenous TRPV1 and CB1 receptor ligand anandamide (ACR neurons). Blocking or deleting the CB1 receptor only reduces both anandamide- and capsaicin-evoked responses in ACR neurons. Deleting the CB1 receptor also reduces the proportion of ACR neurons without any effect on the overall number of capsaicin-responding cells. Regarding the distribution pattern of the two receptors, neurons express CB1 and TRPV1 receptors either isolated in low densities or in close proximity with medium/high densities. We suggest that spatial distribution of the CB1 receptor and TRPV1 contributes to the complexity of their functional interaction.

  8. The short-chain fatty acid receptor, FFA2, contributes to gestational glucose homeostasis.

    PubMed

    Fuller, Miles; Priyadarshini, Medha; Gibbons, Sean M; Angueira, Anthony R; Brodsky, Michael; Hayes, M Geoffrey; Kovatcheva-Datchary, Petia; Bäckhed, Fredrik; Gilbert, Jack A; Lowe, William L; Layden, Brian T

    2015-11-15

    The structure of the human gastrointestinal microbiota can change during pregnancy, which may influence gestational metabolism; however, a mechanism of action remains unclear. Here we observed that in wild-type (WT) mice the relative abundance of Actinobacteria and Bacteroidetes increased during pregnancy. Along with these changes, short-chain fatty acids (SCFAs), which are mainly produced through gut microbiota fermentation, significantly changed in both the cecum and peripheral blood throughout gestation in these mice. SCFAs are recognized by G protein-coupled receptors (GPCRs) such as free fatty acid receptor-2 (FFA2), and we have previously demonstrated that the fatty acid receptor-2 gene (Ffar2) expression is higher in pancreatic islets during pregnancy. Using female Ffar2-/- mice, we explored the physiological relevance of signaling through this GPCR and found that Ffar2-deficient female mice developed fasting hyperglycemia and impaired glucose tolerance in the setting of impaired insulin secretion compared with WT mice during, but not before, pregnancy. Insulin tolerance tests were similar in Ffar2-/- and WT mice before and during pregnancy. Next, we examined the role of FFA2 in gestational β-cell mass, observing that Ffar2-/- mice had diminished gestational expansion of β-cells during pregnancy. Interestingly, mouse genotype had no significant impact on the composition of the gut microbiome, but did affect the observed SCFA profiles, suggesting a functional difference in the microbiota. Together, these results suggest a potential link between increased Ffar2 expression in islets and the alteration of circulating SCFA levels, possibly explaining how changes in the gut microbiome contribute to gestational glucose homeostasis.

  9. Adaptations in AMPA receptor transmission in the nucleus accumbens contributing to incubation of cocaine craving

    PubMed Central

    Loweth, Jessica A.; Tseng, Kuei Y.; Wolf, Marina E.

    2013-01-01

    Cue-induced cocaine craving in rodents intensifies or “incubates” during the first months of withdrawal from long access cocaine self-administration. This incubation phenomenon is relevant to human users who achieve abstinence but exhibit persistent vulnerability to cue-induced relapse. It is well established that incubation of cocaine craving involves complex neuronal circuits. Here we will focus on neuroadaptations in the nucleus accumbens (NAc), a region of convergence for pathways that control cocaine seeking. A key adaptation is a delayed (~3–4 weeks) accumulation of Ca2+-permeable AMPAR receptors (CP-AMPARs) in synapses on medium spiny neurons (MSN) of the NAc. These CP-AMPARs mediate the expression of incubation after prolonged withdrawal, although different mechanisms must be responsible during the first weeks of withdrawal, prior to CP-AMPAR accumulation. The cascade of events leading to CP-AMPAR accumulation is still unclear. However, several candidate mechanisms have been identified. First, mGluR1 has been shown to negatively regulate CP-AMPAR levels in NAc synapses, and it is possible that a withdrawal-dependent decrease in this effect may help explain CP-AMPAR accumulation during incubation. Second, an increase in phosphorylation of GluA1 subunits (at the protein kinase A site) within extrasynaptic homomeric GluA1 receptors (CP-AMPARs) may promote their synaptic insertion and oppose their removal. Finally, elevation of brain-derived neurotrophic factor (BDNF) levels in the NAc may contribute to maintenance of incubation after months of withdrawal, although incubation-related increases in BDNF accumulation do not account for CP-AMPAR accumulation. Receptors and pathways that negatively regulate incubation, such as mGluR1, are promising targets for the development of therapeutic strategies to help recovering addicts maintain abstinence. PMID:23727437

  10. The short chain fatty acid receptor, FFA2, contributes to gestational glucose homeostasis

    DOE PAGES

    Fuller, Miles; Priyadarshini, Medha; Gibbons, Sean M.; ...

    2015-09-22

    The structure of the human gastrointestinal microbiota can change during pregnancy, which may influence gestational metabolism; however, a mechanism of action remains unclear. Here we observed that in wild-type (WT) mice the relative abundance of Actinobacteria and Bacteroidetes increased during pregnancy. Along with these changes, short-chain fatty acids (SCFAs), which are mainly produced through gut microbiota fermentation, significantly changed in both the cecum and peripheral blood throughout gestation in these mice. SCFAs are recognized by G protein-coupled receptors (GPCRs) such as free fatty acid receptor-2 (FFA2), and we have previously demonstrated that the fatty acid receptor-2 gene (Ffar2) expression ismore » higher in pancreatic islets during pregnancy. Using female Ffar2-/- mice, we explored the physiological relevance of signaling through this GPCR and found that Ffar2-deficient female mice developed fasting hyperglycemia and impaired glucose tolerance in the setting of impaired insulin secretion compared with WT mice during, but not before, pregnancy. Insulin tolerance tests were similar in Ffar2-/- and WT mice before and during pregnancy. Next, we examined the role of FFA2 in gestational β-cell mass, observing that Ffar2-/- mice had diminished gestational expansion of β-cells during pregnancy. Interestingly, mouse genotype had no significant impact on the composition of the gut microbiome, but did affect the observed SCFA profiles, suggesting a functional difference in the microbiota. Altogether, these results suggest a potential link between increased Ffar2 expression in islets and the alteration of circulating SCFA levels, possibly explaining how changes in the gut microbiome contribute to gestational glucose homeostasis.« less

  11. The short chain fatty acid receptor, FFA2, contributes to gestational glucose homeostasis

    SciTech Connect

    Fuller, Miles; Priyadarshini, Medha; Gibbons, Sean M.; Angueira, Anthony R.; Brodsky, Michael; Hayes, M. Geoffrey; Kovatcheva-Datchary, Petia; Backhed, Fredrik; Gilbert, Jack A.; Lowe, Jr., William L.; Layden, Brian T.

    2015-09-22

    The structure of the human gastrointestinal microbiota can change during pregnancy, which may influence gestational metabolism; however, a mechanism of action remains unclear. Here we observed that in wild-type (WT) mice the relative abundance of Actinobacteria and Bacteroidetes increased during pregnancy. Along with these changes, short-chain fatty acids (SCFAs), which are mainly produced through gut microbiota fermentation, significantly changed in both the cecum and peripheral blood throughout gestation in these mice. SCFAs are recognized by G protein-coupled receptors (GPCRs) such as free fatty acid receptor-2 (FFA2), and we have previously demonstrated that the fatty acid receptor-2 gene (Ffar2) expression is higher in pancreatic islets during pregnancy. Using female Ffar2-/- mice, we explored the physiological relevance of signaling through this GPCR and found that Ffar2-deficient female mice developed fasting hyperglycemia and impaired glucose tolerance in the setting of impaired insulin secretion compared with WT mice during, but not before, pregnancy. Insulin tolerance tests were similar in Ffar2-/- and WT mice before and during pregnancy. Next, we examined the role of FFA2 in gestational β-cell mass, observing that Ffar2-/- mice had diminished gestational expansion of β-cells during pregnancy. Interestingly, mouse genotype had no significant impact on the composition of the gut microbiome, but did affect the observed SCFA profiles, suggesting a functional difference in the microbiota. Altogether, these results suggest a potential link between increased Ffar2 expression in islets and the alteration of circulating SCFA levels, possibly explaining how changes in the gut microbiome contribute to gestational glucose homeostasis.

  12. Acetylation of EGF Receptor Contributes to Tumor Cell Resistance to Histone Deacetylase Inhibitors

    PubMed Central

    Song, Hui; Li, Chia-Wei; Labaff, Adam M.; Lim, Seung-Oe; Li, Long-Yuan; Kan, Shu-Fen; Chen, Yue; Zhang, Kai; Lang, Jingyu; Xie, Xiaoming; Wang, Yan; Huo, Long-Fei; Hsu, Sheng-Chieh; Chen, Xiaomin; Zhao, Yingming; Hung, Mien-Chie

    2011-01-01

    Alteration of epidermal growth factor receptor (EGFR) is involved in various human cancers and has been intensively investigated. A plethora of evidence demonstrates that posttranslational modifications of EGFR play a pivotal role in controlling its function and metabolism. Here, we show that EGFR can be acetylated by CREB binding protein (CBP) acetyltransferase. Interestingly, EGFR acetylation affects its tyrosine phosphorylation, which may contribute to cancer cell resistance to histone deacetylase inhibitors (HDACIs). Since there is an increasing interest in using HDACIs to treat various cancers in the clinic, our current study provides insights and rationale for selecting effective therapeutic regimen. Consistent with the previous reports, we also show that HDACI combined with EGFR inhibitors achieves better therapeutic outcomes and provides a molecular rationale for the enhanced effect of combination therapy. Our results unveil a critical role of EGFR acetylation that regulates EGFR function, which may have an important clinical implication. PMID:21094134

  13. Prenatal minocycline treatment alters synaptic protein expression, and rescues reduced mother call rate in oxytocin receptor-knockout mice.

    PubMed

    Miyazaki, Shinji; Hiraoka, Yuichi; Hidema, Shizu; Nishimori, Katsuhiko

    2016-04-01

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired communication, difficulty in companionship, repetitive behaviors and restricted interests. Recent studies have shown amelioration of ASD symptoms by intranasal administration of oxytocin and demonstrated the association of polymorphisms in the oxytocin receptor (Oxtr) gene with ASD patients. Deficient pruning of synapses by microglial cells in the brain has been proposed as potential mechanism of ASD. Other researchers have shown specific activation of microglial cells in brain regions related to sociality in patients with ASD. Although the roles of Oxtr and microglia in ASD are in the spotlight, the relationship between them remains to be elucidated. In this study, we found abnormal activation of microglial cells and a reduction of postsynaptic density protein PSD95 expression in the Oxtr-deficient brain. Moreover, pharmacological inhibition of microglia during development can alter the expression of PSD95 and ameliorate abnormal mother-infant communication in Oxtr-deficient mice. Our results suggest that microglial abnormality is a potential mechanism of the development of Oxt/Oxtr mediated ASD-like phenotypes.

  14. Scavenger Receptor MARCO Orchestrates Early Defenses and Contributes to Fungal Containment during Cryptococcal Infection.

    PubMed

    Xu, Jintao; Flaczyk, Adam; Neal, Lori M; Fa, Zhenzong; Eastman, Alison J; Malachowski, Antoni N; Cheng, Daphne; Moore, Bethany B; Curtis, Jeffrey L; Osterholzer, John J; Olszewski, Michal A

    2017-03-15

    The scavenger receptor macrophage receptor with collagenous structure (MARCO) promotes protective innate immunity against bacterial and parasitic infections; however, its role in host immunity against fungal pathogens, including the major human opportunistic fungal pathogen Cryptococcus neoformans, remains unknown. Using a mouse model of C. neoformans infection, we demonstrated that MARCO deficiency leads to impaired fungal control during the afferent phase of cryptococcal infection. Diminished fungal containment in MARCO(-/-) mice was accompanied by impaired recruitment of Ly6C(high) monocytes and monocyte-derived dendritic cells (moDC) and lower moDC costimulatory maturation. The reduced recruitment and activation of mononuclear phagocytes in MARCO(-/-) mice was linked to diminished early expression of IFN-γ along with profound suppression of CCL2 and CCL7 chemokines, providing evidence for roles of MARCO in activation of the CCR2 axis during C. neoformans infection. Lastly, we found that MARCO was involved in C. neoformans phagocytosis by resident pulmonary macrophages and DC. We conclude that MARCO facilitates early interactions between C. neoformans and lung-resident cells and promotes the production of CCR2 ligands. In turn, this contributes to a more robust recruitment and activation of moDC that opposes rapid fungal expansion during the afferent phase of cryptococcal infection.

  15. Loss of the coxsackie and adenovirus receptor contributes to gastric cancer progression

    PubMed Central

    Anders, M; Vieth, M; Röcken, C; Ebert, M; Pross, M; Gretschel, S; Schlag, P M; Wiedenmann, B; Kemmner, W; Höcker, M

    2009-01-01

    Loss of the coxsackie and adenovirus receptor (CAR) has previously been observed in gastric cancer. The role of CAR in gastric cancer pathobiology, however, is unclear. We therefore analysed CAR in 196 R0-resected gastric adenocarcinomas and non-cancerous gastric mucosa samples using immunohistochemistry and immunofluorescence. Coxsackie and adenovirus receptor was found at the surface and foveolar epithelium of all non-neoplastic gastric mucosa samples (n=175), whereas only 56% of gastric cancer specimens showed CAR positivity (P<0.0001). Loss of CAR correlated significantly with decreased differentiation, increased infiltrative depths, presence of distant metastases, and was also associated with reduced carcinoma-specific survival. To clarify whether CAR impacts the tumorbiologic properties of gastric cancer, we subsequently determined the role of CAR in proliferation, migration, and invasion of gastric cancer cell lines by application of specific CAR siRNA or ectopic expression of a human full-length CAR cDNA. These experiments showed that RNAi-mediated CAR knock down resulted in increased proliferation, migration, and invasion of gastric cancer cell lines, whereas enforced ectopic CAR expression led to opposite effects. We conclude that the association of reduced presence of CAR in more severe disease states, together with our findings in gastric cancer cell lines, suggests that CAR functionally contributes to gastric cancer pathogenesis, showing features of a tumour suppressor. PMID:19142187

  16. The nuclear receptors pregnane X receptor and constitutive androstane receptor contribute to the impact of fipronil on hepatic gene expression linked to thyroid hormone metabolism.

    PubMed

    Roques, Béatrice B; Leghait, Julien; Lacroix, Marlène Z; Lasserre, Frédéric; Pineau, Thierry; Viguié, Catherine; Martin, Pascal G P

    2013-10-01

    Fipronil is described as a thyroid disruptor in rat. Based on the hypothesis that this results from a perturbation of hepatic thyroid hormone metabolism, our goal was to investigate the pathways involved in fipronil-induced liver gene expression regulations. First, we performed a microarray screening in the liver of rats treated with fipronil or vehicle. Fipronil treatment led to the upregulation of several genes involved in the metabolism of xenobiotics, including the cytochrome P450 Cyp2b1, Cyp2b2 and Cyp3a1, the carboxylesterases Ces2 and Ces6, the phase II enzymes Ugt1a1, Sult1b1 and Gsta2, and the membrane transporters Abcc2, Abcc3, Abcg5, Abcg8, Slco1a1 and Slco1a4. Based on a large overlap with the target genes of constitutive androstane receptor (CAR) and pregnane X receptor (PXR), we postulated that these two nuclear receptors are involved in mediating the effects of fipronil on liver gene expression in rodents. We controlled that liver gene expression changes induced by fipronil were generally reproduced in mice, and then studied the effects of fipronil in wild-type, CAR- and PXR-deficient mice. For most of the genes studied, the gene expression modulations were abolished in the liver of PXR-deficient mice and were reduced in the liver of CAR-deficient mice. However, CAR and PXR activation in mouse liver was not associated with a marked increase of thyroid hormone clearance, as observed in rat. Nevertheless, our data clearly indicate that PXR and CAR are key modulators of the hepatic gene expression profile following fipronil treatment which, in rats, may contribute to increase thyroid hormone clearance.

  17. CONTRIBUTION OF PROTEASE-ACTIVATED RECEPTOR 1 IN STATUS EPILEPTICUS-INDUCED EPILEPTOGENESIS

    PubMed Central

    Isaev, D.; Lushnikova, I.; Lunko, O.; Zapukhliak, O.; Maximyuk, O.; Romanov, A.; Skibo, G.G.; Tian, C.; Holmes, G.L.; Isaeva, E.

    2015-01-01

    Clinical observations and studies on different animal models of acquired epilepsy consistently demonstrate that blood-brain barrier (BBB) leakage can be an important risk factor for developing recurrent seizures. However, the involved signaling pathways remain largely unclear. Given the important role of thrombin and its major receptor in the brain, protease-activated receptor 1 (PAR1), in the pathophysiology of neurological injury, we hypothesized that PAR1 may contribute to status epilepticus (SE)-induced epileptogenesis and that its inhibition shortly after SE will have neuroprotective and antiepileptogenic effects. Adult rats subjected to lithium-pilocarpine SE were administrated SCH79797 (a PAR1 selective antagonist) after SE termination. Thrombin and PAR1 levels and neuronal cell survival were evaluated 48 hr following SE. The effect of PAR1 inhibition on animal survival, interictal spikes (IIS) and electrographic seizures during the first two weeks after SE and behavioral seizures during the chronic period were evaluated. SE resulted in a high mortality rate and incidence of IIS and seizures in the surviving animals. There was a marked increase in thrombin, decrease in PAR1 immunoreactivity and hippocampal cell loss in the SE-treated rats. Inhibition of PAR1 following SE resulted in a decrease in mortality and morbidity, increase in neuronal cell survival in the hippocampus and suppression of IIS, electrographic and behavioral seizures following SE. These data suggest that the PAR1 signaling pathway contributes to epileptogenesis following SE. Because breakdown of the BBB occurs frequently in brain injuries, PAR1 inhibition may have beneficial effects in a variety of acquired injuries leading to epilepsy. PMID:25843668

  18. Contribution of oxytocin receptor polymorphisms to amygdala activation in schizophrenia spectrum disorders

    PubMed Central

    Bettella, Francesco; Brandt, Christine Lycke; Quintana, Daniel S.; Nerhus, Mari; Bjella, Thomas; Djurovic, Srdjan; Westlye, Lars T.; Andreassen, Ole A.; Melle, Ingrid; Tesli, Martin

    2016-01-01

    Background Oxytocin has been proposed to mediate amygdala dysfunction associated with altered emotion processing in schizophrenia, but the contribution of oxytocin pathway genes is yet to be investigated. Aims To identify potential different contributions of three oxytocin receptor polymorphisms (rs53576, rs237902 and rs2254298) between patients with schizophrenia spectrum disorders (SCZ), affective spectrum disorders (AD) and healthy controls (HC). Method In a total of 346 participants (104 with SCZ, 100 with AD, and 142 HC) underwent genotyping and functional magnetic resonance imaging (fMRI) during an emotional faces matching paradigm. Genetic association analyses were performed to test the possible effects on task-induced BOLD amygdala response to fearful/angry faces. Results In participants with SCZ, the rs237902 G allele was associated with low amygdala activation (left hemisphere: b=−4.99, Bonferroni corrected P=0.04) and interaction analyses showed that this association was disorder specific (left hemisphere: Bonferroni corrected P=0.003; right hemisphere: Bonferroni corrected P=0.03). There were no associations between oxytocin polymorphisms and amygdala activation in the total sample, among AD patients or HC. Conclusions Rs237902 was associated with amygdala activation in response to fearful/angry faces only in patients with SCZ. Our findings indicate that the endogenous oxytocin system could serve as a contributing factor in biological underpinnings of emotion processing and that this contribution is disorder specific. Declaration of interest O.A.A. received speaker’s honoraria from GSK, Otsuka, Lundbeck. Copyright and usage © The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence. PMID:27847593

  19. Contribution of N-methyl-D-aspartate receptors to attention and episodic spatial memory during senescence.

    PubMed

    Guidi, Michael; Rani, Asha; Karic, Semir; Severance, Barrett; Kumar, Ashok; Foster, Thomas C

    2015-11-01

    A decrease in N-methyl-D-aspartate receptor (NMDAR) function is associated with age-related cognitive impairments. However, NMDAR antagonists are prescribed for cognitive decline associated with age-related neurodegenerative disease, raising questions as to the role of NMDAR activity in cognitive function during aging. The current studies examined effects of NMDAR blockade on cognitive task that are sensitive to aging. Young and middle-age rats were trained on the five-choice serial reaction time task (5-CSRTT) and challenged with MK-801 (0.025, 0.05, and 0.1mg/kg or vehicle). Attention deficits were apparent in middle-age and performance of young and middle-age rats was enhanced for low doses of MK-801 (0.025 and 0.05). The beneficial effects on attention were reversed by the highest dose of MK-801. Older animals exhibited a delay-dependent impairment of episodic spatial memory examined on a delayed-matching to place water maze task. Similarly, a low dose of MK-801 (0.05mg/kg) impaired performance with increasing delay and aged animals were more susceptible to disruption by NMDAR blockade. Despite MK-801 impairment of episodic spatial memory, MK-801 had minimal effects on spatial reference memory. Our results confirm that NMDARs contribute to rapidly acquired and flexible spatial memory and support the idea that a decline in NMDAR function contributes to the age-related impairments in cognition.

  20. Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit

    PubMed Central

    Newquist, Gunnar; Novenschi, Alexandra; Kohler, Donovan

    2016-01-01

    Abstract The ability of an animal to detect, discriminate, and respond to odors depends on the functions of its olfactory receptor neurons (ORNs). The extent to which each ORN, upon activation, contributes to chemotaxis is not well understood. We hypothesized that strong activation of each ORN elicits a different behavioral response in the Drosophila melanogaster larva by differentially affecting the composition of its navigational behavior. To test this hypothesis, we exposed Drosophila larvae to specific odorants to analyze the effect of individual ORN activity on chemotaxis. We used two different behavioral paradigms to analyze the chemotaxis response of larvae to odorants. When tested with five different odorants that elicit strong physiological responses from single ORNs, larval behavioral responses toward each odorant differed in the strength of attraction as well as in the composition of discrete navigational elements, such as runs and turns. Further, behavioral responses to odorants did not correlate with either the strength of odor gradients tested or the sensitivity of each ORN to its cognate odorant. Finally, we provide evidence that wild-type larvae with all ORNs intact exhibit higher behavioral variance than mutant larvae that have only a single pair of functional ORNs. We conclude that individual ORNs contribute differently to the olfactory circuit that instructs chemotactic responses. Our results, along with recent studies from other groups, suggest that ORNs are functionally nonequivalent units. These results have implications for understanding peripheral odor coding. PMID:27570823

  1. S-nitrosylated SHP-2 contributes to NMDA receptor-mediated excitotoxicity in acute ischemic stroke

    PubMed Central

    Shi, Zhong-Qing; Sunico, Carmen R.; McKercher, Scott R.; Cui, Jiankun; Feng, Gen-Sheng; Nakamura, Tomohiro; Lipton, Stuart A.

    2013-01-01

    Overproduction of nitric oxide (NO) can cause neuronal damage, contributing to the pathogenesis of several neurodegenerative diseases and stroke (i.e., focal cerebral ischemia). NO can mediate neurotoxic effects at least in part via protein S-nitrosylation, a reaction that covalently attaches NO to a cysteine thiol (or thiolate anion) to form an S-nitrosothiol. Recently, the tyrosine phosphatase Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2) and its downstream pathways have emerged as important mediators of cell survival. Here we report that in neurons and brain tissue NO can S-nitrosylate SHP-2 at its active site cysteine, forming S-nitrosylated SHP-2 (SNO–SHP-2). We found that NMDA exposure in vitro and transient focal cerebral ischemia in vivo resulted in increased levels of SNO–SHP-2. S-Nitrosylation of SHP-2 inhibited its phosphatase activity, blocking downstream activation of the neuroprotective physiological ERK1/2 pathway, thus increasing susceptibility to NMDA receptor-mediated excitotoxicity. These findings suggest that formation of SNO–SHP-2 represents a key chemical reaction contributing to excitotoxic damage in stroke and potentially other neurological disorders. PMID:23382182

  2. Contribution of N-methyl-D-aspartate receptors to attention and episodic spatial memory during senescence

    PubMed Central

    Guidi, Michael; Rani, Asha; Karic, Semir; Severance, Barrett; Kumar, Ashok; Foster, Thomas C.

    2015-01-01

    A decrease in N-methyl-D-aspartate receptor (NMDAR) function is associated with age-related cognitive impairments. However, NMDAR antagonists are prescribed for cognitive decline associated with age-related neurodegenerative disease, raising questions as to the role of NMDAR activity in cognitive function during aging. The current studies examined effects of NMDAR blockade on cognitive task that are sensitive to aging. Young and middle-age rats were trained on the five-choice serial reaction time task (5-CSRTT) and challenged with MK-801 (0.025, 0.05, and 0.1 mg/kg or vehicle). Attention deficits were apparent in middle-age and performance of young and middle-age rats was enhanced for low doses of MK-801 (0.025 and 0.05). The beneficial effects on attention were reversed by the highest dose of MK-801. Older animals exhibited a delay-dependent impairment of episodic spatial memory examined on a delayed-matching to place water maze task. Similarly, a low dose of MK-801 (0.05 mg/kg) impaired performance with increasing delay and aged animals were more susceptible to disruption by NMDAR blockade. Despite MK-801 impairment of episodic spatial memory, MK-801 had minimal effects on spatial reference memory. Our results confirm that NMDARs contribute to rapidly acquired and flexible spatial memory and support the idea that a decline in NMDAR function contributes to the age-related impairments in cognition. PMID:26234588

  3. Severity of eating disorder symptoms related to oxytocin receptor polymorphisms in anorexia nervosa.

    PubMed

    Acevedo, Summer F; Valencia, Celeste; Lutter, Michael; McAdams, Carrie J

    2015-08-30

    Oxytocin is a peptide hormone important for social behavior and differences in psychological traits have been associated with variants of the oxytocin receptor gene in healthy people. We examined whether single nucleotide polymorphisms (SNPs) of the oxytocin receptor gene (OXTR) correlated with clinical symptoms in women with anorexia nervosa, bulimia nervosa, and healthy comparison (HC) women. Subjects completed clinical assessments and provided DNA for analysis. Subjects were divided into four groups: HC, subjects currently with anorexia nervosa (AN-C), subjects with a history of anorexia nervosa but in long-term weight recovery (AN-WR), and subjects with bulimia nervosa (BN). Five SNPs of the oxytocin receptor were examined. Minor allele carriers showed greater severity in most of the psychiatric symptoms. Importantly, the combination of having had anorexia and carrying either of the A alleles for two SNPS in the OXTR gene (rs53576, rs2254298) was associated with increased severity specifically for ED symptoms including cognitions and behaviors associated both with eating and appearance. A review of psychosocial data related to the OXTR polymorphisms examined is included in the discussion. OXTR polymorphisms may be a useful intermediate endophenotype to consider in the treatment of patients with anorexia nervosa.

  4. Severity of eating disorder symptoms related to oxytocin receptor polymorphisms in anorexia nervosa

    PubMed Central

    Acevedo, Summer F.; Valencia, Celeste; Lutter, Michael; McAdams, Carrie J.

    2015-01-01

    Oxytocin is a peptide hormone important for social behavior, and differences in psychological traits have been associated with variants of the oxytocin receptor gene in healthy people. We examined whether small nucleotide polymorphisms (SNPs) of the oxytocin receptor gene (OXTR) correlated with clinical symptoms in women with anorexia nervosa, bulimia nervosa, and healthy comparison (HC) women. Subjects completed clinical assessments and provided DNA for analysis. Subjects were divided into four groups: HC, subjects currently with anorexia nervosa (AN-C), subjects with a history of anorexia nervosa but in long-term weight recovery (AN-WR), and subjects with bulimia nervosa (BN). Five SNPs of the oxytocin receptor were examined. Minor allele carriers showed greater severity in most of the psychiatric symptoms. Importantly, the combination of having had anorexia and carrying either of the A alleles for two SNPS in the OXTR gene (rs53576, rs2254298) was associated with increased severity specifically for ED symptoms including cognitions and behaviors associated both with eating and appearance. A review of psychosocial data related to the OXTR polymorphisms examined is included in the discussion. OXTR polymorphisms may be a useful intermediate endophenotype to consider in the treatment of patients with anorexia nervosa. PMID:26106053

  5. Nicotinic receptor M3 transmembrane domain: position 8' contributes to channel gating.

    PubMed

    De Rosa, María José; Rayes, Diego; Spitzmaul, Guillermo; Bouzat, Cecilia

    2002-08-01

    The nicotinic acetylcholine receptor (nAChR) is a pentamer of homologous subunits with composition alpha(2)(beta)(epsilon)(delta) in adult muscle. Each subunit contains four transmembrane domains (M1-M4). Position 8' of the M3 domain is phenylalanine in all heteromeric alpha subunits, whereas it is a hydrophobic nonaromatic residue in non-alpha subunits. Given this peculiar conservation pattern, we studied its contribution to muscle nAChR activation by combining mutagenesis with single-channel kinetic analysis. Construction of nAChRs carrying different numbers of phenylalanine residues at 8' reveals that the mean open time decreases as a function of the number of phenylalanine residues. Thus, all subunits contribute through this position independently and additively to the channel closing rate. The impairment of channel opening increases when the number of phenylalanine residues at 8' increases from two (wild-type nAChR) to five. The gating equilibrium constant of the latter mutant nAChR is 13-fold lower than that of the wild-type nAChR. The replacement of (alpha)F8', (beta)L8', (delta)L8', and (epsilon)V8' by a series of hydrophobic amino acids reveals that the structural bases of the observed kinetic effects are nonequivalent among subunits. In the alpha subunit, hydrophobic amino acids at 8' lead to prolonged channel lifetimes, whereas they lead either to normal kinetics (delta and epsilon subunits) or impaired channel gating (beta subunit) in the non-alpha subunits. The overall results indicate that 8' positions of the M3 domains of all subunits contribute to channel gating.

  6. (Pro)renin Receptor Contributes to Diabetic Nephropathy Through Enhancing Renal Inflammation

    PubMed Central

    Matavelli, Luis C.; Huang, Jiqian; Siragy, Helmy M.

    2009-01-01

    SUMMARY (Pro)renin receptor (PRR) binding to renin or prorenin mediates Ang II dependent and independent effects. PRR expression was increased in the kidneys of diabetic rats but its role in diabetic nephropathy is unknown. We investigated the contribution of PRR to the development of diabetic nephropathy through enhancement of renal production of tumor necrosis factor-α (TNF-α) and interleukine-1β (IL-1β).Normoglicemic control and streptozotocin-induced diabetes Sprague-Dawley rats were studied. We evaluated urine albumin-to-creatinine ratio (UACR), renal interstitial fluid (RIF) levels of Ang II, TNF-α, and IL-1β, and the renal expression of TNF- α and IL-1β in control, non-treated diabetes, and diabetes treated with PRR blocker (PRRB), AT1 receptor blocker valsartan, or combined therapy, administered directly to the renal cortical interstitium for 14 days via osmotic minipump.Compared to normoglycemic control, UACR and RIF Ang II, TNF-α, and IL-1β were significantly higher in diabetic rats. PRRB or valsartan individually and combined significantly reduced UACR, RIF TNF-α and IL-1β levels. Renal expressions of TNF-α and IL-1β were higher in non-treated diabetic rats and significantly reduced by PRRB or valsartan individually and combined. Renal PRR expression was increased in non-treated and PRRB treated diabetic rats, and reduced in rats receiving valsartan alone or combined therapy. RIF Ang II was not influenced by PRRB, while valsartan alone and combined with PRRB significantly increased its levels.We conclude that PRR is involved in the development and progression of kidney disease in diabetes by enhancing renal production of inflammatory cytokines TNF-α and IL-1β, independently of renal Ang II effects. PMID:19769609

  7. Regulated exocytosis contributes to protein kinase C potentiation of vanilloid receptor activity.

    PubMed

    Morenilla-Palao, Cruz; Planells-Cases, Rosa; García-Sanz, Nuria; Ferrer-Montiel, Antonio

    2004-06-11

    The vanilloid receptor-1 (TRPV1) plays a key role in the perception of peripheral thermal and inflammatory pain. TRPV1 expression and channel activity are notably up-regulated by proalgesic agents. The transduction pathways involved in TRPV1 sensitization are still elusive. We have used a yeast two-hybrid screen to identify proteins that associate with the N terminus of TRPV1. We report that two vesicular proteins, Snapin and synaptotagmin IX (Syt IX), strongly interact in vitro and in vivo with the TRPV1 N-terminal domain. In primary dorsal root ganglion neurons, TRPV1 co-distributes in vesicles with Syt IX and the vesicular protein synaptobrevin. Neither Snapin nor Syt IX affected channel function, but they notably inhibited protein kinase C (PKC)-induced potentiation of TRPV1 channel activity with a potency that rivaled the blockade evoked by botulinum neurotoxin A, a potent blocker of neuronal exocytosis. Noteworthily, we found that PKC activation induced a rapid delivery of functional TRPV1 channels to the plasma membrane. Botulinum neurotoxin A blocked the TRPV1 membrane translocation induced by PKC that was activated with a phorbol ester or the metabotropic glutamate receptor mGluR5. Therefore, our results indicate that PKC signaling promotes at least in part the SNARE-dependent exocytosis of TRPV1 to the cell surface. Taken together, these findings imply that activity-dependent delivery of channels to the neuronal surface may contribute to the buildup and maintenance of thermal inflammatory hyperalgesia in peripheral nociceptor terminals.

  8. Type 2 cannabinoid receptor contributes to the physiological regulation of spermatogenesis.

    PubMed

    Di Giacomo, Daniele; De Domenico, Emanuela; Sette, Claudio; Geremia, Raffaele; Grimaldi, Paola

    2016-04-01

    Type 2 cannabinoid receptor (CB2) has been proposed to play a pivotal role in meiotic entry of male germ cells, similar to retinoic acid (RA). In this study, we showed that activation of CB2with the specific agonist JWH133 [3-(1',1'-dimethylbutyl)-1-deoxy-8-THC] (IC5010(-6)M) mimics epigenetic events induced by RA (IC5010(-7)M) in spermatogonia. Both JWH133 and RA treatments stimulate the expression of the meiotic genes c-KitandStra8, by up-regulating H3K4me3 and down-regulating H3K9me2 levels in genomic regions flanking the transcription start site. Moreover, both agents increase the expression ofPrdm9, the gene encoding a meiosis-specific histone, H3K4me3 methyltransferase, which marks hotspots of recombination in prophase I, thus resulting in a global increase in H3K4me3. Notably, prolonged administration of JWH133 to immature 7 dpp CD-1 mice induced an acceleration of the onset of spermatogenesis, whereas the specific CB2antagonist delayed germ cell differentiation. Thus, both hyper- and hypostimulation of CB2disrupted the temporal dynamics of the spermatogenic cycle. These findings highlight the importance of proper CB2signaling for the maintenance of a correct temporal progression of spermatogenesis and suggest a possible adverse effect of cannabis in deregulating this process.-Di Giacomo, D., De Domenico, E., Sette, C., Geremia, R., Grimaldi, P. Type 2 cannabinoid receptor contributes to the physiological regulation of spermatogenesis.

  9. The contributions of oxytocin and vasopressin pathway genes to human behavior.

    PubMed

    Ebstein, Richard P; Knafo, Ariel; Mankuta, David; Chew, Soo Hong; Lai, Poh San

    2012-03-01

    Arginine vasopressin (AVP) and oxytocin (OXT) are social hormones and mediate affiliative behaviors in mammals and as recently demonstrated, also in humans. There is intense interest in how these simple nonapeptides mediate normal and abnormal behavior, especially regarding disorders of the social brain such as autism that are characterized by deficits in social communication and social skills. The current review examines in detail the behavioral genetics of the first level of human AVP-OXT pathway genes including arginine vasopressin 1a receptor (AVPR1a), oxytocin receptor (OXTR), AVP (AVP-neurophysin II [NPII]) and OXT (OXT neurophysin I [NPI]), oxytocinase/vasopressinase (LNPEP), ADP-ribosyl cyclase (CD38) and arginine vasopressin 1b receptor (AVPR1b). Wherever possible we discuss evidence from a variety of research tracks including molecular genetics, imaging genomics, pharmacology and endocrinology that support the conclusions drawn from association studies of social phenotypes and detail how common polymorphisms in AVP-OXT pathway genes contribute to the behavioral hard wiring that enables individual Homo sapiens to interact successfully with conspecifics. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

  10. Muscle Reactive Oxygen Species (ROS) Contribute to Post-Incisional Guarding via the TRPA1 Receptor

    PubMed Central

    Sugiyama, Daisuke; Kang, Sinyoung; Brennan, Timothy J.

    2017-01-01

    Background Deep tissues and their afferents have unique responses to various stimuli and respond to injury distinctively. However, the types of receptors and endogenous ligands that have a key role in pain after deep tissue incision are unknown. TRPA1 has been shown to mediate pain-related responses in inflammation- and nerve injury-induced pain models. We hypothesized that TRPA1 has an important role in pain behaviors after deep tissue incision. Methods The effect of various doses of intraperitoneal (i.p.) TRPA1 antagonist, HC-030031, on pain behaviors after skin + deep tissue incision of the rat hind paw was measured. In vivo reactive oxygen species (ROS)-imaging and hydrogen peroxide (H2O2) levels after incision were also evaluated. Separate groups of rats were examined for H2O2-evoked pain-related behaviors after injections into the deep tissue or the subcutaneous tissue. Results Guarding pain behavior after skin + deep tissue incision was decreased by i.p. HC-030031. However, HC-030031 did not affect mechanical or heat responses after incision. Treatment either before or after incision was effective against incision-induced guarding behavior. ROS increased after skin + deep tissue incision in both the incised muscle and the skin. Tissue H2O2 also increased in both skin and muscle after incision. H2O2 injection produced pain behaviors when injected into muscle but not after subcutaneous injection. Conclusions This study demonstrates that TRPA1 antagonist HC-030031 reduced spontaneous guarding pain behavior after skin + deep tissue incision. These data indicate that TRPA1 receptors on nociceptors are active in incised fascia and muscle but this is not evident in incised skin. Even though endogenous TRPA1 agonists like ROS and H2O2 were increased in both incised skin and muscle, those in skin do not contribute to nociceptive behaviors. This study suggests that endogenous TRPA1 ligands and the TRPA1 receptor are important targets for acute pain from deep tissue

  11. Orexin receptor 1 signaling contributes to ethanol binge-like drinking: Pharmacological and molecular evidence.

    PubMed

    Carvajal, Francisca; Alcaraz-Iborra, Manuel; Lerma-Cabrera, Jose Manuel; Valor, Luis Miguel; de la Fuente, Leticia; Sanchez-Amate, Maria Del Carmen; Cubero, Inmaculada

    2015-01-01

    Orexins (OX) have been recently implicated in ethanol seeking and self-administration. A few recent studies have provided additional evidence that OX receptor antagonists effectively reduce voluntary ethanol consumption in subjects spontaneously showing high levels of ethanol intake. The present study further evaluates the contribution of OXR1 to excessive binge-like drinking of ethanol in ad libitum-fed C57BL/6J mice from a pharmacological and molecular approach. The main findings in the study are: (1) Icv administration of SB-334867 (3 μg/μl) blunted ethanol (20% v/v), but not saccharin (0.15% w/v) binge-like drinking in a drinking in the dark procedure, without any alteration of chow consumption or total calories ingested; (2) Icv administration of SB-334867 (3 μg/μl) increased the latency to recover the righting reflex after a sedative dose of ethanol without any significant alteration in ethanol peripheral metabolism; (3) four repetitive, 2-h daily episodes of saccharin, but not ethanol binge-like drinking blunted OXR1 mRNA expression in the lateral hypothalamus. Present findings extend the current knowledge pointing to a role for OX signaling in ethanol sedation, which might partially explain the inhibitory effect of OXR1 antagonists on ethanol consumption. Combined pharmacological and molecular data suggesting the contribution of OXR1 in ethanol binge-drinking leading us to propose the idea that targeting OXR1 could represent a novel pharmacological approach to control binge-consumption episodes of ethanol in vulnerable organisms failing to spontaneously reduce OX activity.

  12. Angiotensin II type 1a receptor signalling directly contributes to the increased arrhythmogenicity in cardiac hypertrophy

    PubMed Central

    Yasuno, Shinji; Kuwahara, Koichiro; Kinoshita, Hideyuki; Yamada, Chinatsu; Nakagawa, Yasuaki; Usami, Satoru; Kuwabara, Yoshihiro; Ueshima, Kenji; Harada, Masaki; Nishikimi, Toshio; Nakao, Kazuwa

    2013-01-01

    BACKGROUND AND PURPOSE Angiotensin II has been implicated in the development of various cardiovascular ailments, including cardiac hypertrophy and heart failure. The fact that inhibiting its signalling reduced the incidences of both sudden cardiac death and heart failure in several large-scale clinical trials suggests that angiotensin II is involved in increased cardiac arrhythmogenicity during the development of heart failure. However, because angiotensin II also promotes structural remodelling, including cardiomyocyte hypertrophy and cardiac fibrosis, it has been difficult to assess its direct contribution to cardiac arrhythmogenicity independently of the structural effects. EXPERIMENTAL APPROACH We induced cardiac hypertrophy in wild-type (WT) and angiotensin II type 1a receptor knockout (AT1aR-KO) mice by transverse aortic constriction (TAC). The susceptibility to ventricular tachycardia (VT) assessed in an in vivo electrophysiological study was compared in the two genotypes. The effect of acute pharmacological blockade of AT1R on the incidences of arrhythmias was also assessed. KEY RESULTS As described previously, WT and AT1aR-KO mice with TAC developed cardiac hypertrophy to the same degree, but the incidence of VT was much lower in the latter. Moreover, although TAC induced an increase in tyrosine phosphorylation of connexin 43, a critical component of gap junctional channels, and a reduction in ventricular levels of connexin 43 protein in both genotypes, the effect was significantly ameliorated in AT1aR-KO mice. Acute pharmacological blockade of AT1R also reduced the incidence of arrhythmias. CONCLUSIONS AND IMPLICATIONS Our findings demonstrate that AT1aR-mediated signalling makes a direct contribution to the increase in arrhythmogenicity in hypertrophied hearts independently of structural remodelling. PMID:23937445

  13. Differential contribution of two peroxisomal protein receptors to the maintenance of peroxisomal functions in Arabidopsis.

    PubMed

    Hayashi, Makoto; Yagi, Mina; Nito, Kazumasa; Kamada, Tomoe; Nishimura, Mikio

    2005-04-15

    Peroxisomes in higher plant cells are known to differentiate in function depending on the cell type. Because of the functional differentiation, plant peroxisomes are subdivided into several classes, such as glyoxysomes and leaf peroxisomes. These peroxisomal functions are maintained by import of newly synthesized proteins containing one of two peroxisomal targeting signals known as PTS1 and PTS2. These targeting signals are known to be recognized by the cytosolic receptors, Pex5p and Pex7p, respectively. To demonstrate the contribution of Pex5p and Pex7p to the maintenance of peroxisomal functions in plants, double-stranded RNA constructs were introduced into the genome of Arabidopsis thaliana. Expression of the PEX5 and PEX7 genes was efficiently reduced by the double-stranded RNA-mediated interference in the transgenic Arabidopsis. The Pex5p-deficient Arabidopsis showed reduced activities for both glyoxysomal and leaf peroxisomal functions. An identical phenotype was observed in a transgenic Arabidopsis overexpressing functionally defective Pex5p. In contrast, the Pex7p-deficient Arabidopsis showed reduced activity for glyoxysomal function but not for leaf peroxisomal function. Analyses of peroxisomal protein import in the transgenic Arabidopsis revealed that Pex5p was involved in import of both PTS1-containing proteins and PTS2-containing proteins, whereas Pex7p contributed to the import of only PTS2-containing proteins. Overall, the results indicated that Pex5p and Pex7p play different roles in the maintenance of glyoxysomal and leaf peroxisomal functions in plants.

  14. Endothelial Mineralocorticoid Receptors Differentially Contribute to Coronary and Mesenteric Vascular Function Without Modulating Blood Pressure.

    PubMed

    Mueller, Katelee Barrett; Bender, Shawn B; Hong, Kwangseok; Yang, Yan; Aronovitz, Mark; Jaisser, Frederic; Hill, Michael A; Jaffe, Iris Z

    2015-11-01

    Arteriolar vasoreactivity tightly regulates tissue-specific blood flow and contributes to systemic blood pressure (BP) but becomes dysfunctional in the setting of cardiovascular disease. The mineralocorticoid receptor (MR) is known to regulate BP via the kidney and by vasoconstriction in smooth muscle cells. Although endothelial cells (EC) express MR, the contribution of EC-MR to BP and resistance vessel function remains unclear. To address this, we created a mouse with MR specifically deleted from EC (EC-MR knockout [EC-MR-KO]) but with intact leukocyte MR expression and normal renal MR function. Telemetric BP studies reveal no difference between male EC-MR-KO mice and MR-intact littermates in systolic, diastolic, circadian, or salt-sensitive BP or in the hypertensive responses to aldosterone±salt or angiotensin II±l-nitroarginine methyl ester. Vessel myography demonstrated normal vasorelaxation in mesenteric and coronary arterioles from EC-MR-KO mice. After exposure to angiotensin II-induced hypertension, impaired endothelial-dependent relaxation was prevented in EC-MR-KO mice in mesenteric vessels but not in coronary vessels. Mesenteric vessels from angiotensin II-exposed EC-MR-KO mice showed increased maximum responsiveness to acetylcholine when compared with MR-intact vessels, a difference that is lost with indomethacin+l-nitroarginine methyl ester pretreatment. These data support that EC-MR plays a role in regulating endothelial function in hypertension. Although there was no effect of EC-MR deletion on mesenteric vasoconstriction, coronary arterioles from EC-MR-KO mice showed decreased constriction to endothelin-1 and thromboxane agonist at baseline and also after exposure to hypertension. These data support that EC-MR participates in regulation of vasomotor function in a vascular bed-specific manner that is also modulated by risk factors, such as hypertension.

  15. Contributions of the Epidermal Growth Factor Receptor to Acquisition of Platinum Resistance in Ovarian Cancer Cells

    PubMed Central

    Granados, Michaela L.; Hudson, Laurie G.; Samudio-Ruiz, Sabrina L.

    2015-01-01

    Acquisition of platinum resistance following first line platinum/taxane therapy is commonly observed in ovarian cancer patients and prevents clinical effectiveness. There are few options to prevent platinum resistance; however, demethylating agents have been shown to resensitize patients to platinum therapy thereby demonstrating that DNA methylation is a critical contributor to the development of platinum resistance. We previously reported the Epidermal Growth Factor Receptor (EGFR) is a novel regulator of DNA methyltransferase (DNMT) activity and DNA methylation. Others have shown that EGFR activation is linked to cisplatin treatment and platinum resistance. We hypothesized that cisplatin induced activation of the EGFR mediates changes in DNA methylation associated with the development of platinum resistance. To investigate this, we evaluated EGFR signaling and DNMT activity after acute cisplatin exposure. We also developed an in vitro model of platinum resistance to examine the effects of EGFR inhibition on acquisition of cisplatin resistance. Acute cisplatin treatment activates the EGFR and downstream signaling pathways, and induces an EGFR mediated increase in DNMT activity. Cisplatin resistant cells also showed increased DNMT activity and global methylation. EGFR inhibition during repeated cisplatin treatments generated cells that were more sensitive to cisplatin and did not develop increases in DNA methylation or DNMT activity compared to controls. These findings suggest that activation of EGFR during platinum treatment contributes to the development of platinum resistance. Furthermore, EGFR inhibition may be an effective strategy at attenuating the development of platinum resistance thereby enhancing the effectiveness of chemotherapeutic treatment in ovarian cancer. PMID:26351843

  16. Transient receptor potential melastatin 4 channel contributes to migration of androgen-insensitive prostate cancer cells

    PubMed Central

    Kilch, Tatiana; Jochum, Marcus Martin; Urban, Sabine Katharina; Jung, Volker; Stöckle, Michael; Rother, Karen; Greiner, Markus; Peinelt, Christine

    2015-01-01

    Impaired Ca2+ signaling in prostate cancer contributes to several cancer hallmarks, such as enhanced proliferation and migration and a decreased ability to induce apoptosis. Na+ influx via transient receptor potential melastatin 4 channel (TRPM4) can reduce store-operated Ca2+ entry (SOCE) by decreasing the driving force for Ca2+. In patients with prostate cancer, gene expression of TRPM4 is elevated. Recently, TRPM4 was identified as a cancer driver gene in androgen-insensitive prostate cancer. We investigated TRPM4 protein expression in cancer tissue samples from 20 patients with prostate cancer. We found elevated TRPM4 protein levels in prostatic intraepithelial neoplasia (PIN) and prostate cancer tissue compared to healthy tissue. In primary human prostate epithelial cells (hPEC) from healthy tissue and in the androgen-insensitive prostate cancer cell lines DU145 and PC3, TRPM4 mediated large Na+ currents. We demonstrated significantly increased SOCE after siRNA targeting of TRPM4 in hPEC and DU145 cells. In addition, knockdown of TRPM4 reduced migration but not proliferation of DU145 and PC3 cells. Taken together, our data identify TRPM4 as a regulator of SOCE in hPEC and DU145 cells, demonstrate a role for TRPM4 in cancer cell migration and suggest that TRPM4 is a promising potential therapeutic target. PMID:26496025

  17. Low-Density Lipoprotein Receptor Contributes to β-Carotene Uptake in the Maternal Liver

    PubMed Central

    Shete, Varsha; Costabile, Brianna K.; Kim, Youn-Kyung; Quadro, Loredana

    2016-01-01

    Vitamin A regulates many essential mammalian biological processes, including embryonic development. β-carotene is the main source of vitamin A in the human diet. Once ingested, it is packaged into lipoproteins, predominantly low-density lipoproteins (LDL), and transported to different sites within the body, including the liver and developing tissues, where it can either be stored or metabolized to retinoids (vitamin A and its derivatives). The molecular mechanisms of β-carotene uptake by the liver or developing tissues remain elusive. Here, we investigated the role of the LDL receptor (LDLr) in β-carotene uptake by maternal liver, placenta and embryo. We administered a single dose of β-carotene to Ldlr+/− and Ldlr−/− pregnant mice via intraperitoneal injection at mid-gestation and monitored the changes in β-carotene content among maternal lipoproteins and the liver, as well as the accumulation of β-carotene in the placental–fetal unit. We showed an abnormal β-carotene distribution among serum lipoproteins and reduced hepatic β-carotene uptake in Ldlr−/− dams. These data strongly imply that LDLr significantly contributes to β-carotene uptake in the adult mouse liver. In contrast, LDLr does not seem to mediate acquisition of β-carotene by the placental–fetal unit. PMID:27916814

  18. Transient Receptor Potential Vanilloid-1 in Epidermal Keratinocytes May Contribute to Acute Pain in Herpes Zoster.

    PubMed

    Han, Sang Bum; Kim, Hyeree; Cho, Sang Hyun; Lee, Jeong Deuk; Chung, Jin Ho; Kim, Hei Sung

    2016-03-01

    The role of transient receptor potential vanilloid-1 (TRPV1) in the initiation of neurogenic inflammation and transduction of pain is well established. In this study 33 patients with herpes zoster (HZ) were recruited from a single centre and underwent a questionnaire interview at their first visit. Punch biopsies from the HZ lesions and the contralateral unaffected skin were performed to localize and quantify the expression of TRPV1. Immunofluorescent staining for TRPV1 was most prominent in the epidermal keratinocytes. Both TRPV1 mRNA and protein levels were significantly higher in the HZ epidermis than in control epidermis (relative ratio 1.62 ± 0.27, p = 0.033 and 2.55 ± 0.51, p = 0.005, respectively). Protein TRPV1 ratio (HZ lesion/control) correlated with the degree of pain (measured on a visual analogue scale; VAS) (p = 0.017) and was significantly lower in patients who had taken either HZ medication or painkillers prior to their visit. These results suggest that non-neuronal TRPV1 may contribute to acute pain in herpes zoster.

  19. Upregulation of Transient Receptor Potential Canonical Channels Contributes to Endotoxin-Induced Pulmonary Arterial Stenosis

    PubMed Central

    Chen, Gui-Lan; Jiang, Hongni; Zou, Fangdong

    2016-01-01

    Background Septic shock is a pathologic condition caused by endotoxin-producing bacteria, and often associated with severe pulmonary hypertension. Inflammation is a major systemic response to endotoxin; however, it is unknown whether endotoxin has a direct impact on pulmonary arteries that contributes to pathogenesis of pulmonary hypertension. Material/Methods Rat pulmonary arteries and primary pulmonary arterial smooth muscle cells (PASMCs) were cultured in vitro and treated with lipopolysaccharide (LPS) and blockers of transient receptor potential canonical (TRPC) channels. Neointimal growth and arterial stenosis were observed on cryosections of cultured pulmonary arteries. Proliferation of PASMCs was examined by a WST-1 (water-soluble tetrazolium salt) assay. Expression of TRPC genes in pulmonary arteries and PASMCs were detected and quantified by real-time polymerase chain reaction and Western blotting. Results LPS significantly induced neointimal growth and stenosis of pulmonary arteries and promoted proliferation of PASMCs. TRPC channel blockers 2-aminoethoxydiphenyl borate and SKF-96365 inhibited LPS-induced remodeling of pulmonary arteries and PASMC proliferation. Expression of TRPC1/3/4/6 was detected in pulmonary arteries and PASMCs. LPS treatment dramatically increased the expression of TRPC3 and TRPC4 at both messenger RNA and protein levels. Conclusions LPS stimulates stenosis of pulmonary arteries through enhancement of TRPC-mediated Ca2+ entry into PASMCs, which is caused by upregulation of TRPC3 and TRPC4 channels. PMID:27471122

  20. [Contributions of neuropsychology to anti-NMDA receptor antibody encephalitis: a literature review].

    PubMed

    Luna-Lario, P; Hernaez-Goni, P; Tirapu-Ustarroz, J

    2016-05-01

    Limbic encephalitis generated by anti-N-methyl-D-aspartate (NMDA) receptor antibodies is an acute and severe neurological entity, which is more prevalent in young females and is associated to an underlying tumour. Since it leads to severe cognitive impairment, thought needs to be given to the contributions of neuropsychology to the diagnosis, development and treatment of the disease, which have received little attention from researchers to date. A review is conducted of the prior literature, evaluating the measurement of the cognitive symptoms (predominantly mnemonic and executive) associated to this disease. Valid, reliable neuropsychological instruments are proposed, and it is suggested that neuropsychological measures may be used as parameters to follow up these patients which help monitor their functionality in daily living once they have recovered from the acute phase. Similarly they can become a basis on which to assemble rehabilitation programmes that favour the accomplishment of personal autonomy and the patients' reintegration in the community. Nevertheless, we stress the need to include neuropsychologists and neuropsychiatrists in not only the detection but also the treatment of these patients so as to enable them to recover their personal independence and re-adapt to their natural settings.

  1. Alterations in Purkinje cell GABAA receptor pharmacology following oxygen and glucose deprivation and cerebral ischemia reveal novel contribution of β1-subunit-containing receptors

    PubMed Central

    Kelley, Melissa H.; Ortiz, Justin; Shimizu, Kaori; Grewal, Himmat; Quillinan, Nidia; Herson, Paco S.

    2013-01-01

    Cerebellar Purkinje cells (PCs) are particularly sensitive to cerebral ischemia, and decreased GABAA receptor function following injury is thought to contribute to PC sensitivity to ischemia-induced excitotoxicity. Here we examined the functional properties of the GABAA receptors that are spared following ischemia in cultured Purkinje cells from rat and in vivo ischemia in mouse. Using subunit-specific positive modulators of GABAA receptors, we observed that oxygen and glucose deprivation (OGD) and cardiac arrest-induced cerebral ischemia cause a decrease in sensitivity to the β2/3-subunit-preferring compound, etomidate. However, sensitivity to propofol, a β-subunit-acting compound that modulates β1–3-subunits, was not affected by OGD. The α/γ-subunit-act-ing compounds, diazepam and zolpidem, were also unaffected by OGD. We performed single-cell reverse transcription–polymerase chain reaction on isolated PCs from acutely dissociated cerebellar tissue and observed that PCs expressed the β1-subunit, contrary to previous reports examining GABAA receptor subunit expression in PCs. GABAA receptor β1-subunit protein was also detected in cultured PCs by western blot and by immunohistochemistry in the adult mouse cerebellum and levels remained unaffected by ischemia. High concentrations of loreclezole (30 µm) inhibited PC GABA-mediated currents, as previously demonstrated with β1-subunit-containing GABAA receptors expressed in heterologous systems. From our data we conclude that PCs express the β1-subunit and that there is a greater contribution of β1-subunit-containing GABAA receptors following OGD. PMID:23176253

  2. Signaling via Tumor Necrosis Factor Receptor 1 but Not Toll-Like Receptor 2 Contributes Significantly to Hydrosalpinx Development following Chlamydia muridarum Infection

    PubMed Central

    Dong, Xiaohua; Liu, Yuanjun; Chang, Xiaotong; Lei, Lei

    2014-01-01

    Chlamydial infection in the lower genital tract can lead to hydrosalpinx, which is accompanied by activation of both pattern recognition receptor TLR2- and inflammatory cytokine receptor TNFR1-mediated signaling pathways. In the current study, we compared the relative contributions of these two receptors to chlamydial induction of hydrosalpinx in mice. We found that mice with or without deficiencies in TLR2 or TNFR1 displayed similar time courses of live organism shedding from vaginal swabs, suggesting that these receptor-mediated signaling pathways are not required for controlling chlamydial lower genital infection. However, mice deficient in TNFR1 but not TLR2 developed significantly reduced hydrosalpinx. The decreased pathogenicity correlated with a significant reduction in interleukin-17 by in vitro-restimulated splenocytes of TNFR1-deficient mice. Although TLR2-deficient mice developed hydrosalpinx as severe as that of wild-type mice, peritoneal macrophages from mice deficient in TLR2 but not TNFR1 produced significantly reduced cytokines upon chlamydial stimulation, suggesting that reduced macrophage responses to chlamydial infection do not always lead to a reduction in hydrosalpinx. Thus, we have demonstrated that the signaling pathways triggered by the cytokine receptor TNFR1 play a more significant role in chlamydial induction of hydrosalpinx than those mediated by the pattern recognition receptor TLR2, which has laid a foundation for further revealing the chlamydial pathogenic mechanisms. PMID:24549331

  3. Do gastrointestinal taste receptors contribute to associative learning and foraging behavior?

    PubMed

    Golden, G J; Hussey, A M; Kimball, B A

    2012-12-01

    Foraging behavior is an expression of learning, context, and experience arising from integration of sensory information obtained during feeding with postingestive consequences of food ingestion. Although it has been well established that gustatory and olfactory systems of the mouth and nose provide sensory information to the consumer (in the form of flavor), sweet and bitter taste receptors have recently been identified in the intestinal tract of humans and rodents. It remains possible that sensory information generated in the gut could contribute to the learning process. Thus, a series of experiments was conducted to determine if classical associative learning occurs when the conditional stimulus circumvents oronasal presentation via direct delivery to the gut or peritoneal cavity. Mice receiving an intragastric infusion of 5 mM sodium saccharin immediately followed by LiCl administration demonstrated a significant decrease in preference for 5 mM saccharin in 4 consecutive 23 h, 2-bottle preference tests versus water (P = 0.0053). Saccharin was highly preferred in mice receiving intragastric (IG) saccharin only or interperitoneal (i.p.) injection of LiCl only. This reduced preference indicated that mice "tasted" saccharin infused into the gut. However, efforts to replicate with a reduced infusion volume failed to result in decreased preference. To understand if there were alternative pathways for oral detection of infused saccharin, mice received intragastric infusions (5.4 mM) and i.p. injections (10.8 mM) of sodium fluorescein. Fluorescence was observed from the tongues and esophagi of mice infused with volumes of 0.5 mL or more or injected with volumes of 0.25 mL or greater. Interperitoneal injections of 5 mM saccharin in mice resulted in reduced preference for 5 mM saccharin presented orally in 2-bottle preference tests (P = 0.0287). Oral delivery of a 500-fold less concentration of saccharin (0.01 mM) during conditioning resulted in a similar preference

  4. Modulation of Receptor Phosphorylation Contributes to Activation of Peroxisome Proliferator Activated Receptor α by Dehydroepiandrosterone and Other Peroxisome Proliferators

    PubMed Central

    Tamasi, Viola; Miller, Kristy K. Michael; Ripp, Sharon L.; Vila, Ermin; Geoghagen, Thomas E.; Prough, Russell A.

    2008-01-01

    Dehydroepiandrosterone (DHEA), a C19 human adrenal steroid, activates peroxisome proliferator-activated receptor α (PPARα) in vivo but does not ligand-activate PPARα in transient transfection experiments. We demonstrate that DHEA regulates PPARα action by altering both the levels and phosphorylation status of the receptor. Human hepatoma cells (HepG2) were transiently transfected with the expression plasmid encoding PPARα and a plasmid containing two copies of fatty acyl coenzyme oxidase (FACO) peroxisome-proliferator activated receptor responsive element consensus oligonucleotide in a luciferase reporter gene. Nafenopin treatment increased reporter gene activity in this system, whereas DHEA treatment did not. Okadaic acid significantly decreased nafenopin-induced reporter activity in a concentration-dependent manner. Okadaic acid treatment of primary rat hepatocytes decreased both DHEA- and nafenopin-induced FACO activity in primary rat hepatocytes. DHEA induced both PPARα mRNA and protein levels, as well as PP2A message in primary rat hepatocytes. Western blot analysis showed that the serines at positions 12 and 21 were rapidly dephosphorylated upon treatment with DHEA and nafenopin. Results using specific protein phosphatase inhibitors suggested that protein phosphatase 2A (PP2A) is responsible for DHEA action, and protein phosphatase 1 might be involved in nafenopin induction. Mutation of serines at position 6, 12, and 21 to an uncharged alanine residue significantly increased transcriptional activity, whereas mutation to negative charged aspartate residues (mimicking receptor phosphorylation) decreased transcriptional activity. DHEA action involves induction of PPARα mRNA and protein levels as well as increased PPARα transcriptional activity through decreasing receptor phosphorylation at serines in the AF1 region. PMID:18079279

  5. Chemokine receptor Cxcr4 contributes to kidney fibrosis via multiple effectors.

    PubMed

    Yuan, Amy; Lee, Yashang; Choi, Uimook; Moeckel, Gilbert; Karihaloo, Anil

    2015-03-01

    Kidney fibrosis is the final common pathway for virtually every type of chronic kidney disease and is a consequence of a prolonged healing response that follows tissue inflammation. Chronic kidney inflammation ultimately leads to progressive tissue injury and scarring/fibrosis. Several pathways have been implicated in the progression of kidney fibrosis. In the present study, we demonstrate that G protein-coupled chemokine (C-X-C motif) receptor (CXCR)4 was significantly upregulated after renal injury and that sustained activation of Cxcr4 expression augmented the fibrotic response. We demonstrate that after unilateral ureteral obstruction (UUO), both gene and protein expression of Cxcr4 were highly upregulated in tubular cells of the nephron. The increased Cxcr4 expression in tubules correlated with their increased dedifferentiated state, leading to increased mRNA expression of platelet-derived growth factor (PDGF)-α, transforming growth factor (TGF)-β1, and concurrent loss of bone morphogenetic protein 7 (Bmp7). Ablation of tubular Cxcr4 attenuated UUO-mediated fibrotic responses, which correlated with a significant reduction in PDGF-α and TGF-β1 levels and preservation of Bmp7 expression after UUO. Furthermore, Cxcr4(+) immune cells infiltrated the obstructed kidney and further upregulate their Cxcr4 expression. Genetic ablation of Cxcr4 from macrophages was protective against UUO-induced fibrosis. There was also reduced total kidney TGF-β1, which correlated with reduced Smad activation and α-smooth muscle actin levels. We conclude that chronic high Cxcr4 expression in multiple effector cell types can contribute to the pathogenesis of renal fibrosis by altering their biological profile. This study uncovered a novel cross-talk between Cxcr4-TGF-β1 and Bmp7 pathways and may provide novel targets for interrupting the progression of fibrosis.

  6. Sulfonylurea receptor 1 contributes to the astrocyte swelling and brain edema in acute liver failure.

    PubMed

    Jayakumar, A R; Valdes, V; Tong, X Y; Shamaladevi, N; Gonzalez, W; Norenberg, M D

    2014-02-01

    Astrocyte swelling (cytotoxic brain edema) is the major neurological complication of acute liver failure (ALF), a condition in which ammonia has been strongly implicated in its etiology. Ion channels and transporters are known to be involved in cell volume regulation, and a disturbance in these systems may result in cell swelling. One ion channel known to contribute to astrocyte swelling/brain edema in other neurological disorders is the ATP-dependent, nonselective cation (NCCa-ATP) channel. We therefore examined its potential role in the astrocyte swelling/brain edema associated with ALF. Cultured astrocytes treated with 5 mM ammonia showed a threefold increase in the sulfonylurea receptor type 1 (SUR1) protein expression, a marker of NCCa-ATP channel activity. Blocking SUR1 with glibenclamide significantly reduced the ammonia-induced cell swelling in cultured astrocytes. Additionally, overexpression of SUR1 in ammonia-treated cultured astrocytes was significantly reduced by cotreatment of cells with BAY 11-7082, an inhibitor of NF-κB, indicating the involvement of an NF-κB-mediated SUR1 upregulation in the mechanism of ammonia-induced astrocyte swelling. Brain SUR1 mRNA level was also found to be increased in the thioacetamide (TAA) rat model of ALF. Additionally, we found a significant increase in SUR1 protein expression in rat brain cortical astrocytes in TAA-treated rats. Treatment with glibenclamide significantly reduced the brain edema in this model of ALF. These findings strongly suggest the involvement of NCCa-ATP channel in the astrocyte swelling/brain edema in ALF and that targeting this channel may represent a useful approach for the treatment of the brain edema associated with ALF.

  7. Redox modification of ryanodine receptors contributes to sarcoplasmic reticulum Ca2+ leak in chronic heart failure.

    PubMed

    Terentyev, Dmitry; Györke, Inna; Belevych, Andriy E; Terentyeva, Radmila; Sridhar, Arun; Nishijima, Yoshinori; de Blanco, Esperanza Carcache; Khanna, Savita; Sen, Chandan K; Cardounel, Arturo J; Carnes, Cynthia A; Györke, Sandor

    2008-12-05

    Abnormal cardiac ryanodine receptor (RyR2) function is recognized as an important factor in the pathogenesis of heart failure (HF). However, the specific molecular causes underlying RyR2 defects in HF remain poorly understood. In the present study, we used a canine model of chronic HF to test the hypothesis that the HF-related alterations in RyR2 function are caused by posttranslational modification by reactive oxygen species generated in the failing heart. Experimental approaches included imaging of cytosolic ([Ca(2+)](c)) and sarcoplasmic reticulum (SR) luminal Ca(2+) ([Ca(2+)]SR) in isolated intact and permeabilized ventricular myocytes and single RyR2 channel recording using the planar lipid bilayer technique. The ratio of reduced to oxidized glutathione, as well as the level of free thiols on RyR2 decreased markedly in failing versus control hearts consistent with increased oxidative stress in HF. RyR2-mediated SR Ca(2+) leak was significantly enhanced in permeabilized myocytes, resulting in reduced [Ca(2+)](SR) in HF compared to control cells. Both SR Ca(2+) leak and [Ca(2+)](SR) were partially normalized by treating HF myocytes with reducing agents. Conversely, oxidizing agents accelerated SR Ca(2+) leak and decreased [Ca(2+)](SR) in cells from normal hearts. Moreover, exposure to antioxidants significantly improved intracellular Ca(2+)-handling parameters in intact HF myocytes. Single RyR2 channel activity was significantly higher in HF versus control because of increased sensitivity to activation by luminal Ca(2+) and was partially normalized by reducing agents through restoring luminal Ca(2+) sensitivity oxidation of control RyR2s enhanced their luminal Ca(2+) sensitivity, thus reproducing the HF phenotype. These findings suggest that redox modification contributes to abnormal function of RyR2s in HF, presenting a potential therapeutic target for treating HF.

  8. Contributions of Conserved Residues at the Gating Interface of Glycine Receptors*

    PubMed Central

    Pless, Stephan A.; Leung, Ada W. Y.; Galpin, Jason D.; Ahern, Christopher A.

    2011-01-01

    Glycine receptors (GlyRs) are chloride channels that mediate fast inhibitory neurotransmission and are members of the pentameric ligand-gated ion channel (pLGIC) family. The interface between the ligand binding domain and the transmembrane domain of pLGICs has been proposed to be crucial for channel gating and is lined by a number of charged and aromatic side chains that are highly conserved among different pLGICs. However, little is known about specific interactions between these residues that are likely to be important for gating in α1 GlyRs. Here we use the introduction of cysteine pairs and the in vivo nonsense suppression method to incorporate unnatural amino acids to probe the electrostatic and hydrophobic contributions of five highly conserved side chains near the interface, Glu-53, Phe-145, Asp-148, Phe-187, and Arg-218. Our results suggest a salt bridge between Asp-148 in loop 7 and Arg-218 in the pre-M1 domain that is crucial for channel gating. We further propose that Phe-145 and Phe-187 play important roles in stabilizing this interaction by providing a hydrophobic environment. In contrast to the equivalent residues in loop 2 of other pLGICs, the negative charge at Glu-53 α1 GlyRs is not crucial for normal channel function. These findings help decipher the GlyR gating pathway and show that distinct residue interaction patterns exist in different pLGICs. Furthermore, a salt bridge between Asp-148 and Arg-218 would provide a possible mechanistic explanation for the pathophysiologically relevant hyperekplexia, or startle disease, mutant Arg-218 → Gln. PMID:21835920

  9. Ryanodine receptor 2 contributes to hemorrhagic shock-induced bi-phasic vascular reactivity in rats

    PubMed Central

    Zhou, Rong; Ding, Xiao-li; Liu, Liang-ming

    2014-01-01

    Aim: Ryanodine receptor 2 (RyR2) is a critical component of intracellular Ca2+ signaling in vascular smooth muscle cells (VSMCs). The aim of this study was to investigate the role of RyR2 in abnormal vascular reactivity after hemorrhagic shock in rats. Methods: SD rats were hemorrhaged and maintained mean arterial pressure (MAP) at 40 mmHg for 30 min or 2 h, and then superior mesenteric arteries (SMA) rings were prepared to measure the vascular reactivity. In other experiments, SMA rings of normal rats and rat VSMCs were exposed to a hypoxic medium for 10 min or 3 h. SMA rings of normal rats and VSMCs were transfected with siRNA against RyR2. Intracellular Ca2+ release in VSMCs was assessed using Fura-2/AM. Results: The vascular reactivity of the SMA rings from hemorrhagic rats was significantly increased in the early stage (30 min), but decreased in the late stage (2 h) of hemorrhagic shock. Similar results were observed in the SMA rings exposed to hypoxia for 10 min or 3 h. The enhanced vascular reactivity of the SMA rings exposed to hypoxia for 10 min was partly attenuated by transfection with RyR2 siRNA, whereas the blunted vascular reactivity of the SMA rings exposed to hypoxia for 3 h was partly restored by transfection with RyR2 siRNA. Treatment with the RyR agonist caffeine (1 mmol/L) significantly increased Ca2+ release in VSMCs exposed to hypoxia for 10 min or 3 h, which was partially antagonized by transfection with RyR2 siRNA. Conclusion: RyR2-mediated Ca2+ release contributes to the development of bi-phasic vascular reactivity induced by hemorrhagic shock or hypoxia. PMID:25263335

  10. (Pro)renin receptor contributes to regulation of renal epithelial sodium channel

    PubMed Central

    Quadri, Syed; Siragy, Helmy M.

    2016-01-01

    Recent studies reported increased (Pro)renin receptor (PRR) expression during low-salt intake. We hypothesized that PRR plays a role in regulation of renal epithelial sodium channel (ENaC) through serum and glucocorticoid-inducible kinase isoform 1 (SGK-1)-neural precursor cell expressed, developmentally downregulated 4–2 (Nedd4–2) signaling pathway. Male Sprague–Dawley rats on normal-sodium diet and mouse renal inner medullary collecting duct cells treated with NaCl at 130 mmol/l (normal salt), or 63 mmol/l (low salt) were studied. PRR and α-ENaC expressions were evaluated 1 week after right uninephrectomy and left renal interstitial administration of 5% dextrose, scramble shRNA, or PRR shRNA (n = 6 each treatment). In-vivo PRR shRNA significantly reduced expressions of PRR throughout the kidney and α-ENaC subunits in the renal medulla. In inner medullary collecting duct cells, low salt or angiopoietin II (Ang II) augmented the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC (P < 0.05). Low salt or Ang II increased the phosphorylation of Nedd4–2. In cells treated with low salt or Ang II, PRR siRNA significantly downregulated the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC expression (P < 0.05). We conclude that PRR contributes to the regulation of α-ENaC via SGK-1-Nedd4–2 signaling pathway. PMID:26771338

  11. Identification of transmembrane domain 6 & 7 residues that contribute to the binding pocket of the urotensin II receptor.

    PubMed

    Holleran, Brian J; Domazet, Ivana; Beaulieu, Marie-Eve; Yan, Li Ping; Guillemette, Gaétan; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard

    2009-04-15

    Urotensin II (U-II), a cyclic undecapeptide, is the natural ligand of the urotensin II (UT) receptor, a G protein-coupled receptor. In the present study, we used the substituted-cysteine accessibility method to identify specific residues in transmembrane domains (TMDs) six and seven of the rat urotensin II receptor (rUT) that contribute to the formation of the binding pocket of the receptor. Each residue in the R256(6.32)-Q283(6.59) fragment of TMD6 and the A295(7.31)-T321(7.57) fragment of TMD7 was mutated, individually, to a cysteine. The resulting mutants were expressed in COS-7 cells, which were subsequently treated with the positively charged methanethiosulfonate-ethylammonium (MTSEA) or the negatively charged methanethiosulfonate-ethylsulfonate (MTSES) sulfhydryl-specific alkylating agents. MTSEA treatment resulted in a significant reduction in the binding of TMD6 mutants F268C(6.44) and W278C(6.54) and TMD7 mutants L298C(7.34), T302C(7.38), and T303C(7.39) to (125)I-U-II. MTSES treatment resulted in a significant reduction in the binding of two additional mutants, namely L282C(6.58) in TMD6 and Y300C(7.36) in TMD7. These results suggest that specific residues orient themselves within the water-accessible binding pocket of the rUT receptor. This approach, which allowed us to identify key determinants in TMD6 and TMD7 that contribute to the UT receptor binding pocket, enabled us to further refine our homology-based model of how U-II interacts with its cognate receptor.

  12. NMDA receptor NR2B subunits contribute to PTZ-kindling-induced hippocampal astrocytosis and oxidative stress.

    PubMed

    Zhu, Xinjian; Dong, Jingde; Shen, Kai; Bai, Ying; Zhang, Yuan; Lv, Xuan; Chao, Jie; Yao, Honghong

    2015-05-01

    The N-methyl-d-aspartate (NMDA) receptor plays an important role in the pathophysiology of several neurological diseases, including epilepsy. The present study investigated the effect of NMDA receptor NR2B subunits on pentylenetetrazole (PTZ)-kindling-induced pathological and biochemical events in mice. Our results showed that PTZ-kindling up-regulates the expression of NMDA receptor NR2B subunits in the hippocampus and that kindled mice were characterized by significant astrocytosis and neuron loss in the hippocampus. Oxidative stress, including excessive malondialdehyde (MDA) production and decreased enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), were detected in the hippocampus after the mice were fully kindled. Additionally, expression of brain-derived neurotrophic factor (BDNF) in the hippocampus was found to be up-regulated in PTZ-kindled mice. However, selectively blocking NMDA receptor NR2B subunits by ifenprodil significantly suppressed PTZ-kindling-induced hippocampal astrocytosis, oxidative stress and neuron loss. Furthermore, blocking NMDA receptor NR2B subunits also abolished PTZ-kindling-induced BDNF expression. These results indicate that NMDA receptor NR2B subunits contribute to epilepsy-associated pathological and biochemical events, including hippocampal astrocytosis, oxidative stress and neuron loss, and these events might be correlated with up-regulation of BDNF expression.

  13. Dopamine D(3) receptors contribute to methamphetamine-induced alterations in dopaminergic neuronal function: role of hyperthermia.

    PubMed

    Baladi, Michelle G; Newman, Amy H; Nielsen, Shannon M; Hanson, Glen R; Fleckenstein, Annette E

    2014-06-05

    Methamphetamine administration causes long-term deficits to dopaminergic systems that, in humans, are thought to be associated with motor slowing and memory impairment. Methamphetamine interacts with the dopamine transporter (DAT) and increases extracellular concentrations of dopamine that, in turn, binds to a number of dopamine receptor subtypes. Although the relative contribution of each receptor subtype to the effects of methamphetamine is not fully known, non-selective dopamine D2/D3 receptor antagonists can attenuate methamphetamine-induced changes to dopamine systems. The present study extended these findings by testing the role of the dopamine D3 receptor subtype in mediating the long-term dopaminergic, and for comparison serotonergic, deficits caused by methamphetamine. Results indicate that the dopamine D3 receptor selective antagonist, PG01037, attenuated methamphetamine-induced decreases in striatal DAT, but not hippocampal serotonin (5HT) transporter (SERT), function, as assessed 7 days after treatment. However, PG01037 also attenuated methamphetamine-induced hyperthermia. When methamphetamine-induced hyperthermia was maintained by treating rats in a warm ambient environment, PG01037 failed to attenuate the effects of methamphetamine on DAT uptake. Furthermore, PG01037 did not attenuate methamphetamine-induced decreases in dopamine and 5HT content. Taken together, the present study demonstrates that dopamine D3 receptors mediate, in part, the long-term deficits in DAT function caused by methamphetamine, and that this effect likely involves an attenuation of methamphetamine-induced hyperthermia.

  14. Functional phylogenetics reveals contributions of pleiotropic peptide action to ligand-receptor coevolution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The evolution of peptidergic signaling has been accompanied by a significant degree of ligand-receptor coevolution. Closely related clusters of peptide signaling molecules are observed to activate related groups of receptors, implying that genes encoding these ligands may orchestrate an array of fu...

  15. Kinetic Contributions to Gating by Interactions Unique to N-methyl-d-aspartate (NMDA) Receptors*

    PubMed Central

    Borschel, William F.; Cummings, Kirstie A.; Tindell, LeeAnn K.; Popescu, Gabriela K.

    2015-01-01

    Among glutamate-gated channels, NMDA receptors produce currents that subside with unusually slow kinetics, and this feature is essential to the physiology of central excitatory synapses. Relative to the homologous AMPA and kainate receptors, NMDA receptors have additional intersubunit contacts in the ligand binding domain that occur at both conserved and non-conserved sites. We examined GluN1/GluN2A single-channel currents with kinetic analyses and modeling to probe these class-specific intersubunit interactions for their role in glutamate binding and receptor gating. We found that substitutions that eliminate such interactions at non-conserved sites reduced stationary gating, accelerated deactivation, and imparted sensitivity to aniracetam, an AMPA receptor-selective positive modulator. Abolishing unique contacts at conserved sites also reduced stationary gating and accelerated deactivation. These results show that contacts specific to NMDA receptors, which brace the heterodimer interface within the ligand binding domain, stabilize actively gating receptor conformations and result in longer bursts and slower deactivations. They support the view that the strength of the heterodimer interface modulates gating in both NMDA and non-NMDA receptors and that unique interactions at this interface are responsible in part for basic differences between the kinetics of NMDA and non-NMDA currents at glutamatergic synapses. PMID:26370091

  16. GABA(B) and NMDA receptors contribute to spindle-like oscillations in rat thalamus in vitro.

    PubMed

    Jacobsen, R B; Ulrich, D; Huguenard, J R

    2001-09-01

    blockade were more pronounced in 0.65 mM than in 2 mM external [Mg(2+)]. Thus spindle-like oscillations occur in rat thalamic slices in vitro, and we find that, in addition to the previously demonstrated contributions of GABA(A) and AMPA receptors to these oscillations, NMDA and GABA(B) receptors are also involved. The strong influence of external [Mg(2+)] on GABAergic pharmacology and a contribution of NMDA receptors during oscillations suggest a link between the excitability of NMDA receptors and the activation of GABA(B)R-mediated inhibitory postsynaptic currents.

  17. Activations of muscarinic M1 receptors in the anterior cingulate cortex contribute to the antinociceptive effect via GABAergic transmission

    PubMed Central

    Matsuzaki, Yu; Honda, Kenji; Eto, Fumihiro; Furukawa, Tomonori; Migita, Keisuke; Irie, Keiichi; Mishima, Kenichi; Ueno, Shinya

    2017-01-01

    Background Cholinergic systems regulate the synaptic transmission resulting in the contribution of the nociceptive behaviors. Anterior cingulate cortex is a key cortical area to play roles in nociception and chronic pain. However, the effect of the activation of cholinergic system for nociception is still unknown in the cortical area. Here, we tested whether the activation of cholinergic receptors can regulate nociceptive behaviors in adult rat anterior cingulate cortex by integrative methods including behavior, immunohistochemical, and electrophysiological methods. Results We found that muscarinic M1 receptors were clearly expressed in the anterior cingulate cortex. Using behavioral tests, we identified that microinjection of a selective muscarinic M1 receptors agonist McN-A-343 into the anterior cingulate cortex dose dependently increased the mechanical threshold. In contrast, the local injection of McN-A-343 into the anterior cingulate cortex showed normal motor function. The microinjection of a selective M1 receptors antagonist pirenzepine blocked the McN-A-343-induced antinociceptive effect. Pirenzepine alone into the anterior cingulate cortex decreased the mechanical thresholds. The local injection of the GABAA receptors antagonist bicuculline into the anterior cingulate cortex also inhibited the McN-A-343-induced antinociceptive effect and decreased the mechanical threshold. Finally, we further tested whether the activation of M1 receptors could regulate GABAergic transmission using whole-cell patch-clamp recordings. The activation of M1 receptors enhanced the frequency of spontaneous and miniature inhibitory postsynaptic currents as well as the amplitude of spontaneous inhibitory postsynaptic currents in the anterior cingulate cortex. Conclusions These results suggest that the activation of muscarinic M1 receptors in part increased the mechanical threshold by increasing GABAergic transmitter release and facilitating GABAergic transmission in the anterior

  18. Evaluation of the Contribution of Multiple DAMPs and DAMP Receptors in Cell Death-Induced Sterile Inflammatory Responses

    PubMed Central

    Patel, Zubin; Rock, Kenneth L.

    2014-01-01

    When cells die by necrosis in vivo they stimulate an inflammatory response. It is thought that this response is triggered when the injured cells expose proinflammatory molecules, collectively referred to as damage associated molecular patterns (DAMPs), which are recognized by cells or soluble molecules of the innate or adaptive immune system. Several putative DAMPs and/or their receptors have been identified, but whether and how much they participate in responses in vivo is incompletely understood, and they have not previously been compared side-by-side in the same models. This study focuses on evaluating the contribution of multiple mechanisms that have been proposed to or potentially could participate in cell death-induced inflammation: The third component of complement (C3), ATP (and its receptor P2X7), antibodies, the C-type lectin receptor Mincle (Clec4e), and protease-activated receptor 2 (PAR2). We investigate the role of these factors in cell death-induced inflammation to dead cells in the peritoneum and acetaminophen-induced liver damage. We find that mice deficient in antibody, C3 or PAR2 have impaired inflammatory responses to dying cells. In contrast there was no reduction in inflammation to cell death in the peritoneum or liver of mice that genetically lack Mincle, the P2X7 receptor or that were treated with apyrase to deplete ATP. These results indicate that antibody, complement and PAR2 contribute to cell death-induced inflammation but that Mincle and ATP- P2X7 receptor are not required for this response in at least 2 different in vivo models. PMID:25127469

  19. Potentiation of the transient receptor potential vanilloid 1 channel contributes to pruritogenesis in a rat model of liver disease.

    PubMed

    Belghiti, Majedeline; Estévez-Herrera, Judith; Giménez-Garzó, Carla; González-Usano, Alba; Montoliu, Carmina; Ferrer-Montiel, Antonio; Felipo, Vicente; Planells-Cases, Rosa

    2013-04-05

    Persistent pruritus is a common disabling dermatologic symptom associated with different etiologic factors. These include primary skin conditions, as well as neuropathic, psychogenic, or systemic disorders like chronic liver disease. Defective clearance of potential pruritogenic substances that activate itch-specific neurons innervating the skin is thought to contribute to cholestatic pruritus. However, because the underlying disease-specific pruritogens and itch-specific neuronal pathways and mechanism(s) are unknown, symptomatic therapeutic intervention often leads to no or only limited success. In the current study, we aimed to first validate rats with bile duct ligation (BDL) as a model for hepatic pruritus and then to evaluate the contribution of inflammation, peripheral neuronal sensitization, and specific signaling pathways and subpopulations of itch-responsive neurons to scratching behavior and thermal hypersensitivity. Chronic BDL rats displayed enhanced scratching behavior and thermal hyperalgesia indicative of peripheral neuroinflammation. BDL-induced itch and hypersensitivity involved a minor contribution of histaminergic/serotonergic receptors, but significant activation of protein-activated receptor 2 (PAR2) receptors, prostaglandin PGE2 formation, and potentiation of transient receptor potential vanilloid 1 (TRPV1) channel activity. The sensitization of dorsal root ganglion nociceptors in BDL rats was associated with increased surface expression of PAR2 and TRPV1 proteins and an increase in the number of PAR2- and TRPV1-expressing peptidergic neurons together with a shift of TRPV1 receptor expression to medium sized dorsal root ganglion neurons. These results suggest that pruritus and hyperalgesia in chronic cholestatic BDL rats are associated with neuroinflammation and involve PAR2-induced TRPV1 sensitization. Thus, pharmacological modulation of PAR2 and/or TRPV1 may be a valuable therapeutic approach for patients with chronic liver pruritus

  20. Quantitative dissection of the binding contributions of ligand lysines of the receptor-associated protein (RAP) to the low density lipoprotein receptor-related protein (LRP1).

    PubMed

    Dolmer, Klavs; Campos, Andres; Gettins, Peter G W

    2013-08-16

    Although lysines are known to be critical for ligand binding to LDL receptor family receptors, relatively small reductions in affinity have been found when such lysines have been mutated. To resolve this paradox, we have examined the specific binding contributions of four lysines, Lys-253, Lys-256, Lys-270, and Lys-289, in the third domain (D3) of receptor-associated protein (RAP), by eliminating all other lysine residues. Using D3 variants containing lysine subsets, we examined binding to the high affinity fragment CR56 from LRP1. With this simplification, we found that elimination of the lysine pairs Lys-253/Lys-256 and Lys-270/Lys-289 resulted in increases in Kd of 1240- and 100,000-fold, respectively. Each pair contributed additively to overall affinity, with 61% from Lys-270/Lys-289 and 39% from Lys-253/Lys-256. Furthermore, the Lys-270/Lys-289 pair alone could bind different single CR domains with similar affinity. Within the pairs, binding contributions of Lys-270 ≫ Lys-256 > Lys-253 ∼ Lys-289 were deduced. Importantly, however, Lys-289 could significantly compensate for the loss of Lys-270, thus explaining how previous studies have underestimated the importance of Lys-270. Calorimetry showed that favorable enthalpy, from Lys-256 and Lys-270, overwhelmingly drives binding, offset by unfavorable entropy. Our findings support a mode of ligand binding in which a proximal pair of lysines engages the negatively charged pocket of a CR domain, with two such pairs of interactions (requiring two CR domains), appropriately separated, being alone sufficient to provide the low nanomolar affinity found for most protein ligands of LDL receptor family members.

  1. Transient receptor potential vanilloid type-1 (TRPV-1) channels contribute to cutaneous thermal hyperaemia in humans.

    PubMed

    Wong, Brett J; Fieger, Sarah M

    2010-11-01

    The initial, rapid increase in skin blood flow in response to direct application of heat is thought to be mediated by an axon reflex, which is dependent on intact cutaneous sensory nerves. We tested the hypothesis that inhibition of transient receptor potential vanilloid type 1 (TRPV-1) channels, which are putative channels located on sensory nerves, would attenuate the skin blood flow response to local heating in humans. Ten subjects were equipped with four microdialysis fibres which were randomly assigned one of four treatments: (1) vehicle control (90% propylene glycol + 10% lactated Ringer solution); (2) 20 mm capsazepine to inhibit TRPV-1 channels; (3) 10 mm l-NAME to inhibit NO synthase; and (4) combined 20 mm capsazepine + 10 mm l-NAME. Following baseline measurements, the temperature of skin heaters was increased from 33°C to 42°C at a rate of 1.0°C every 10 s and local temperature was held at 42°C for 20-30 min until a stable plateau in skin blood flow was achieved. An index of skin blood flow was measured directly over each microdialysis site via laser-Doppler flowmetry (LDF). Beat-by-beat blood pressure was measured via photoplethysmography and verified via automated brachial auscultation. At the end of the local heating protocol, temperature of the heaters was increased to 43°C and 28 mm nitroprusside was infused to achieve maximal vasodilatation. Cutaneous vascular conductance (CVC) was calculated as LDF/mean arterial pressure and normalized to maximal values (%CVCmax). Initial peak in capsazepine (44 ± 4%CVCmax), l-NAME (56 ± 4%CVCmax) and capsazepine + l-NAME (32 ± 6%CVCmax) sites was significantly attenuated compared to control (87 ± 5%CVCmax; P < 0.001 for all conditions). The plateau phase of thermal hyperaemia was significantly attenuated in capsazepine (73 ± 6%CVCmax), l-NAME (47 ± 5%CVCmax) and capsazepine + l-NAME (31 ± 7%CVCmax) sites compared to control (92 ± 5%CVCmax; P < 0.001 for all conditions). These data suggest TRPV-1

  2. Extrasynaptic δ-containing GABAA receptors in the nucleus accumbens dorsomedial shell contribute to alcohol intake

    PubMed Central

    Nie, Hong; Rewal, Mridula; Gill, T. Michael; Ron, Dorit; Janak, Patricia H.

    2011-01-01

    Recent findings suggest that extrasynaptic δ-subunit–containing GABAA receptors are sensitive to low-to-moderate concentrations of alcohol, raising the possibility that these receptors mediate the reinforcing effects of alcohol after consumption of one or a few drinks. We used the technique of viral-mediated RNAi to reduce expression of the GABAA receptor δ-subunit in adult rats in localized regions of the nucleus accumbens (NAc) to test the hypothesis that δ-subunit–containing GABAA receptors in the NAc are necessary for oral alcohol consumption. We found that knockdown of the δ-subunit in the medial shell region of the NAc, but not in the ventral or lateral shell or in the core, reduced alcohol intake. In contrast, δ-subunit knockdown in the medial shell did not affect intake of a 2% sucrose solution, suggesting that the effects of GABAA receptor δ-subunit reduction are specific to alcohol. These results provide strong evidence that extrasynaptic δ-subunit–containing GABAA receptors in the medial shell of the NAc are critical for the reinforcing effects of oral ethanol. PMID:21368141

  3. The contribution of endogenous benzodiazepine receptor ligands to the pathogenesis of hepatic encephalopathy

    SciTech Connect

    Basile, A.S. )

    1991-02-01

    The involvement of the gamma-aminobutyric acid A(GABAA) receptor complex in the pathogenesis of hepatic encephalopathy (HE) was examined in galactosamine-treated rabbits with HE caused by fulminant hepatic failure. Radioligand binding to the constituent components of the GABAA receptor complex was unchanged in rabbits with HE. However, partially purified extracts from encephalopathic rabbit brain were approximately three times more potent in inhibiting ({sup 3}H)Ro 15-1788 binding to benzodiazepine (BZ) receptors than extracts from control rabbits. The inhibition of radioligand binding to the BZ receptor produced by these extracts was competitive and reversible and was significantly enhanced by GABA. Further purification of these extracts by high-performance liquid chromatography (HPLC) indicated that the inhibitory activity was localized in several peaks, some of which had retention times corresponding to 1,4-benzodiazepine standards. The presence of diazepam in these extracts was confirmed using mass spectroscopy. Both mass spectroscopic and radiometric techniques demonstrated that the concentration of diazepam in brain extracts from encephalopathic rabbits was approximately 4 times greater than control extracts. These findings link the presence of BZ receptor agonists to the development of a neuropathological condition, thereby providing a rational basis for the use of BZ receptor antagonists in the management of HE in man.

  4. Differential Contribution of Transmembrane Domains IV, V, VI, and VII to Human Angiotensin II Type 1 Receptor Homomer Formation.

    PubMed

    Young, Brent M; Nguyen, Elaine; Chedrawe, Matthew A J; Rainey, Jan K; Dupré, Denis J

    2017-02-24

    G protein-coupled receptors (GPCRs) play an important role in drug therapy and represent one of the largest families of drug targets. The angiotensin II type 1 receptor (AT1R) is notable as it has a central role in the treatment of cardiovascular disease. Blockade of AT1R signaling has been shown to alleviate hypertension and improve outcomes in patients with heart failure. Despite this, it has become apparent that our initial understanding of AT1R signaling is oversimplified. There is considerable evidence to suggest that AT1R signaling is highly modified in the presence of receptor-receptor interactions, but there is very little structural data available to explain this phenomenon even with the recent elucidation of the AT1R crystal structure. The current study investigates the involvement of transmembrane domains in AT1R homomer assembly with the goal of identifying hydrophobic interfaces that contribute to receptor-receptor affinity. A recently published crystal structure of the AT1R was used to guide site-directed mutagenesis of outward-facing hydrophobic residues within the transmembrane region of the AT1R. Bioluminescence resonance energy transfer was employed to analyze how receptor mutation affects the assembly of AT1R homomers with a specific focus on hydrophobic residues. Mutations within transmembrane domains IV, V, VI, and VII had no effect on angiotensin-mediated β-arrestin1 recruitment; however, they exhibited differential effects on the assembly of AT1R into oligomeric complexes. Our results demonstrate the importance of hydrophobic amino acids at the AT1R transmembrane interface and provide the first glimpse of the requirements for AT1R complex assembly.

  5. Spinal leptin contributes to the development of morphine antinociceptive tolerance by activating the STAT3-NMDA receptor pathway in rats.

    PubMed

    Hu, Fen; Cui, Yu; Guo, Ruixian; Chen, Jingfu; Guo, Runming; Shen, Ning; Hua, Xiaoxiao; Mo, Liqiu; Feng, Jianqiang

    2014-08-01

    Leptin, an adipokine synthesized mainly by non‑neuronal tissues, has been reported to contribute to the pathogenesis of neuropathic pain. It has been hypothesized that morphine tolerance and neuropathic pain share some common pathological mechanisms. The present study was designed to examine whether spinal leptin is implicated in the development of morphine antinociceptive tolerance, and whether spinal leptin induces the activation of signal transducer and activator of transcription 3 (STAT3) signaling pathway and the NR1 subunit of N‑methyl‑D‑aspartate (NMDA) receptor, in morphine antinociceptive tolerance in rats. The results demonstrated that intrathecal (i.t.) administration of a leptin antagonist (LA) prevented the development of morphine antinociceptive tolerance in rats. Further studies revealed that the levels of the spinal leptin and the leptin receptor (Ob‑R) were time‑dependently increased following chronic morphine treatment. Mechanistic examination indicated that chronic morphine triggered activation of the STAT3 pathway and an increase in the expression of the NR1 subunit of the NMDA receptor, which was ameliorated by i.t. administration of AG490 [a Janus kinase (JAK)‑STAT inhibitor]. The increased activation of STAT3 and the NR1 subunit was markedly attenuated by i.t. treatment with LA. In addition, the spinal administration of AG490 or MK‑801 (a non‑competitive NMDA receptor inhibitor) blocked the development of morphine antinociceptive tolerance. Taken together, these results have demonstrated, for the first time, to the best of our knowledge, that spinal leptin contributes to the development of morphine antinociceptive tolerance by activating the spinal STAT3‑NMDA receptor pathway.

  6. Glycine and GABAA receptors mediate tonic and phasic inhibitory processes that contribute to prepulse inhibition in the goldfish startle network

    PubMed Central

    Curtin, Paul C. P.; Preuss, Thomas

    2015-01-01

    Prepulse inhibition (PPI) is understood as a sensorimotor gating process that attenuates sensory flow to the startle pathway during early stages (20–1000 ms) of information processing. Here, we applied in vivo electrophysiology and pharmacology to determine if PPI is mediated by glycine receptors (GlyRs) and/or GABAA receptors (GABAARs) in the goldfish auditory startle circuit. Specifically, we used selective antagonists to dissect the contributions of target receptors on sound-evoked postsynaptic potentials (PSPs) recorded in the neurons that initiate startle, the Mauthner-cells (M-cell). We found that strychnine, a GlyR antagonist, disrupted a fast-activated (5 ms) and rapidly (<50 ms) decaying (feed-forward) inhibitory process that contributes to PPI at 20 ms prepulse/pulse inter-stimulus intervals (ISI). Additionally we observed increases of the evoked postsynaptic potential (PSP) peak amplitude (+87.43 ± 21.53%, N = 9) and duration (+204 ± 48.91%, N = 9). In contrast, treatment with bicuculline, a GABAAR antagonist, caused a general reduction in PPI across all tested interstimulus intervals (ISIs) (20–500 ms). Bicuculline also increased PSP peak amplitude (+133.8 ± 10.3%, N = 5) and PSP duration (+284.95 ± 65.64%, N = 5). Treatment with either antagonist also tonically increased post-synaptic excitability in the M-cells, reflected by an increase in the magnitude of antidromically-evoked action potentials (APs) by 15.07 ± 3.21%, N = 7 and 16.23 ± 7.08%, N = 5 for strychnine and bicuculline, respectively. These results suggest that GABAARs and GlyRs are functionally segregated to short- and longer-lasting sound-evoked (phasic) inhibitory processes that contribute to PPI, with the mediation of tonic inhibition by both receptor systems being critical for gain control within the M-cell startle circuit. PMID:25852486

  7. Contribution of NMDA glutamate and nicotinic acetylcholine receptor mechanisms in the discrimination of ethanol-nicotine mixtures.

    PubMed

    Ford, Matthew M; Davis, Natalie L; McCracken, Aubrey D; Grant, Kathleen A

    2013-10-01

    Ethanol and nicotine are commonly coabused drugs, and the incidence of codependence is greater than would be expected on the basis of the summed probability of dependence on each drug alone. Previous findings from our laboratory and others suggest that interactive mechanisms at the level of discriminative stimulus (S(D)) effects may contribute to this coabuse phenomenon. Specifically, ethanol overshadows the nicotine S(D) whereas nicotine potentiates the stimulus salience of ethanol when the two drugs are conditioned as a drug mixture. The goal of the current study was to begin to delineate the pharmacological bases of these ethanol-nicotine interactions. Three groups of C57BL/6J mice were trained to discriminate 0.8 mg/kg nicotine + 0.5 g/kg ethanol (0.8 N + 0.5 E), 0.8 N + 1.0 E, or 0.8 N + 2.0 E. An NMDA receptor antagonist (MK-801) and three nACh receptor ligands were tested for their ability to generalize from or antagonize, respectively, the drug mixtures. MK-801 fully generalized from the 0.8 N + 1.0 E and 0.8 N + 2.0 E mixtures and partially generalized from 0.8 N + 0.5 E. In contrast, nACh receptor ligands had minimal influence in blocking the perception of 0.8 N + 1.0 E and 0.8 N + 2.0 E mixtures, and only mecamylamine partially blocked 0.8 N+0.5 E. Reduced and enhanced contributions of nACh and NMDA receptors, respectively, in the discrimination of ethanol-nicotine mixtures may contribute to the overshadowing and potentiation phenomena observed previously.

  8. Contributions of peripheral and central opioid receptors to antinociception in rat muscle pain models.

    PubMed

    Sánchez, Eva Ma; Bagües, Ana; Martín, Ma Isabel

    2010-10-01

    Administration of hypertonic saline (HS) is an accepted model to study muscular pain. HS-induced nociceptive responses were tested in masseter, already described, and in two new pain models of spinally innervated muscles (gastrocnemius and triceps) developed in rats at our laboratory. HS administration in the masseter induced vigorous hindpaw shaking and in the gastrocnemius or triceps, paw withdrawal or flexing. Participation of the central and peripheral opioid receptors in HS-induced pain is compared in these muscles: masseter, innervated by trigeminal nerve, and gastrocnemius and triceps by spinal nerves. Morphine and loperamide were used to reveal peripheral and central components of opioid analgesia. Both agonists reduced HS-induced nociceptive behaviours in the masseter and were antagonised by the opioid antagonist naloxone and by naloxone methiodide, an opioid receptor antagonist that poorly penetrates the blood-brain barrier. Unexpectedly, in the gastrocnemius and triceps, morphine, but not loperamide, decreased the nociceptive behaviour and this effect was only reversed by naloxone. So, peripheral opioid receptors seem to participate in HS-induced masseter pain, whereas only central opioid receptors reduced the nociception in gastrocnemius and triceps. Our results suggest that the use of peripheral opioids can be more advantageous than central opioids for treatment of orofacial muscular pain.

  9. Contribution of Resting Conductance, GABAA-Receptor Mediated Miniature Synaptic Currents and Neurosteroid to Chloride Homeostasis in Central Neurons

    PubMed Central

    Yelhekar, Tushar D.; Druzin, Michael

    2017-01-01

    Abstract Maintenance of a low intraneuronal Cl– concentration, [Cl–]i, is critical for inhibition in the CNS. Here, the contribution of passive, conductive Cl– flux to recovery of [Cl–]i after a high load was analyzed in mature central neurons from rat. A novel method for quantifying the resting Cl– conductance, important for [Cl–]i recovery, was developed and the possible contribution of GABAA and glycine receptors and of ClC-2 channels to this conductance was analyzed. The hypothesis that spontaneous, action potential-independent release of GABA is important for [Cl–]i recovery was tested. [Cl–]i was examined by gramicidin-perforated patch recordings in medial preoptic neurons. Cells were loaded with Cl– by combining GABA or glycine application with a depolarized voltage, and the time course of [Cl–]i was followed by measurements of the Cl– equilibrium potential, as obtained from the current recorded during voltage ramps combined with GABA or glycine application. The results show that passive Cl– flux contributes significantly, in the same order of magnitude as does K+-Cl– cotransporter 2 (KCC2), to [Cl–]i recovery and that Cl– conductance accounts for ∼ 6% of the total resting conductance. A major fraction of this resting Cl– conductance is picrotoxin (PTX)-sensitive and likely due to open GABAA receptors, but ClC-2 channels do not contribute. The results also show that when the decay of GABAA receptor-mediated miniature postsynaptic currents (minis) is slowed by the neurosteroid allopregnanolone, such minis may significantly quicken [Cl–]i recovery, suggesting a possible steroid-regulated role for minis in the control of Cl– homeostasis. PMID:28374007

  10. Melatonin receptor signaling contributes to neuroprotection upon arousal from torpor in thirteen-lined ground squirrels

    PubMed Central

    Schwartz, Christine; Ballinger, Mallory A.

    2015-01-01

    The brain of mammalian hibernators is naturally protected. Hibernating ground squirrels undergo rapid and extreme changes in body temperature and brain perfusion as they cycle between lengthy torpor bouts and brief periods of euthermia called interbout arousals (IBAs). Arousal from torpor to IBA occurs rapidly, but there is no evidence of brain injury accompanying this extreme physiological transition. Production of the hormone melatonin accompanies arousal, suggesting that it plays a protective role at this time. Here, we investigated mechanisms of melatonin receptor-mediated protection in the brain of the hibernating ground squirrel. We administered the competitive melatonin receptor antagonist luzindole (30 mg/kg ip) to ground squirrels at the predicted end of a torpor bout, triggering an arousal. We found that luzindole-treated animals exhibited caspase-3 activity two times higher than vehicle-treated animals in the hypothalamus at midarousal (P = 0.01), suggesting that melatonin receptor signaling is important for protection in this brain region. We also found a 30% decline in succinate-fueled mitochondrial respiration in luzindole-treated animals compared with vehicle-treated animals (P = 0.019), suggesting that melatonin receptor signaling is important for optimal mitochondrial function during arousal from torpor. The mitochondrial effects of luzindole treatment were seen only during the hibernation season, indicating that this effect is specifically important for arousal from torpor. These data provide evidence for the protective role of melatonin receptor signaling during the extreme physiological transition that occurs when a hibernating mammal arouses from torpor and provide further evidence for regional and seasonal changes in the hibernator brain. PMID:26354846

  11. Nerve injury-induced changes in Homer/glutamate receptor signaling contribute to the development and maintenance of neuropathic pain.

    PubMed

    Obara, Ilona; Goulding, Scott P; Hu, Jia-Hua; Klugmann, Matthias; Worley, Paul F; Szumlinski, Karen K

    2013-10-01

    While group 1 metabotropic glutamate receptors (mGluRs) and ionotropic N-methyl-d-aspartate (NMDA) receptors regulate nociception, the precise molecular mechanism(s) contributing to glutamate signaling in chronic pain remain unclear. Here we not only confirmed the key involvement of Homer proteins in neuropathic pain, but also distinguished between the functional roles for different Homer family members and isoforms. Chronic constriction injury (CCI) of the sciatic nerve induced long-lasting, time-dependent increases in the postsynaptic density expression of the constitutively expressed (CC) isoforms Homer1b/c and/or Homer2a/b in the spinal dorsal horn and supraspinal structures involved in nociception (prefrontal cortex, thalamus), that co-occurred with increases in their associated mGluRs, NR2 subunits of the NMDA receptor, and the activation of downstream kinases. Virus-mediated overexpression of Homer1c and Homer2b after spinal (intrathecal) virus injection exacerbated CCI-induced mechanical and cold hypersensitivity, however, Homer1 and Homer2 gene knockout (KO) mice displayed no changes in their neuropathic phenotype. In contrast, overexpression of the immediate early gene (IEG) Homer1a isoform reduced, while KO of Homer1a gene potentiated neuropathic pain hypersensitivity. Thus, nerve injury-induced increases in CC-Homers expression promote pain in pathological states, but IEG-Homer induction protects against both the development and maintenance of neuropathy. Additionally, exacerbated pain hypersensitivity in transgenic mice with reduced Homer binding to mGluR5 supports also an inhibitory role for Homer interactions with mGluR5 in mediating neuropathy. Such data indicate that nerve injury-induced changes in glutamate receptor/Homer signaling contribute in dynamic but distinct ways to neuropathic pain processing, which has relevance for the etiology of chronic pain symptoms and its treatment.

  12. Contribution of Adsorbed Protein Films to Nanoscopic Vibrations Exhibited by Bacteria Adhering through Ligand-Receptor Bonds.

    PubMed

    Song, Lei; Sjollema, Jelmer; Norde, Willem; Busscher, Henk J; van der Mei, Henny C

    2015-09-29

    Bacteria adhering to surfaces exhibit nanoscopic vibrations that depend on the viscoelasticity of the bond. The quantification of the nanoscopic vibrations of bacteria adhering to surfaces provides new opportunities to better understand the properties of the bond through which bacteria adhere and the mechanisms by which they resist detachment. Often, however, bacteria do not adhere to bare surfaces but to adsorbed protein films, on which adhesion involves highly specific ligand-receptor binding next to nonspecific DLVO interaction forces. Here we determine the contribution of adsorbed salivary protein and fibronectin films to vibrations exhibited by adhering streptococci and staphylococci, respectively. The streptococcal strain used has the ability to adhere to adsorbed salivary proteins films through antigen I/II ligand-receptor binding, while the staphylococcal strain used adheres to adsorbed fibronectin films through a proteinaceous ligand-receptor bond. In the absence of ligand-receptor binding, electrostatic interactions had a large impact on vibration amplitudes of adhering bacteria on glass. On an adsorbed salivary protein film, vibration amplitudes of adhering streptococci depended on the film softness as determined by QCM-D and were reduced after film fixation using glutaraldehyde. On a relatively stiff fibronectin film, cross-linking the film in glutaraldehyde hardly reduced its softness, and accordingly fibronectin film softness did not contribute to vibration amplitudes of adhering staphylococci. However, fixation of the staphylococcus-fibronectin bond further decreased vibration amplitudes, while fixation of the streptococcus bond hardly impacted vibration amplitudes. Summarizing, this study shows that both the softness of adsorbed protein films and the properties of the bond between an adhering bacterium and an adsorbed protein film play an important role in bacterial vibration amplitudes. These nanoscopic vibrations reflect the viscoelasticity of the

  13. Toll-Like Receptor 9 Contributes to Defense against Acinetobacter baumannii Infection

    PubMed Central

    Noto, Michael J.; Boyd, Kelli L.; Burns, William J.; Varga, Matthew G.; Peek, Richard M.

    2015-01-01

    Acinetobacter baumannii is a common nosocomial pathogen capable of causing severe diseases associated with significant morbidity and mortality in impaired hosts. Pattern recognition receptors, such as the Toll-like receptors (TLRs), play a key role in pathogen detection and function to alert the immune system to infection. Here, we examine the role for TLR9 signaling in response to A. baumannii infection. In a murine model of A. baumannii pneumonia, TLR9−/− mice exhibit significantly increased bacterial burdens in the lungs, increased extrapulmonary bacterial dissemination, and more severe lung pathology compared with those in wild-type mice. Following systemic A. baumannii infection, TLR9−/− mice have significantly increased bacterial burdens in the lungs, as well as decreased proinflammatory cytokine and chemokine production. These results demonstrate that TLR9-mediated pathogen detection is important for host defense against the opportunistic pathogen Acinetobacter baumannii. PMID:26238713

  14. Toll-Like Receptor 9 Contributes to Defense against Acinetobacter baumannii Infection.

    PubMed

    Noto, Michael J; Boyd, Kelli L; Burns, William J; Varga, Matthew G; Peek, Richard M; Skaar, Eric P

    2015-10-01

    Acinetobacter baumannii is a common nosocomial pathogen capable of causing severe diseases associated with significant morbidity and mortality in impaired hosts. Pattern recognition receptors, such as the Toll-like receptors (TLRs), play a key role in pathogen detection and function to alert the immune system to infection. Here, we examine the role for TLR9 signaling in response to A. baumannii infection. In a murine model of A. baumannii pneumonia, TLR9(-/-) mice exhibit significantly increased bacterial burdens in the lungs, increased extrapulmonary bacterial dissemination, and more severe lung pathology compared with those in wild-type mice. Following systemic A. baumannii infection, TLR9(-/-) mice have significantly increased bacterial burdens in the lungs, as well as decreased proinflammatory cytokine and chemokine production. These results demonstrate that TLR9-mediated pathogen detection is important for host defense against the opportunistic pathogen Acinetobacter baumannii.

  15. Bone Cell-autonomous Contribution of Type 2 Cannabinoid Receptor to Breast Cancer-induced Osteolysis.

    PubMed

    Sophocleous, Antonia; Marino, Silvia; Logan, John G; Mollat, Patrick; Ralston, Stuart H; Idris, Aymen I

    2015-09-04

    The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations. Under conditions in which these ligands are used at the nanomolar range, HU308 and JWH133 enhanced human and mouse breast cancer cell-induced osteoclastogenesis and exacerbated osteolysis, and these effects were attenuated in cultures obtained from CB2-deficient mice or in the presence of a CB2 receptor blocker. HU308 and JWH133 had no effects on osteoblast growth or differentiation in the presence of conditioned medium from breast cancer cells, but under these circumstances both agents enhanced parathyroid hormone-induced osteoblast differentiation and the ability to support osteoclast formation. Mechanistic studies in osteoclast precursors and osteoblasts showed that JWH133 and HU308 induced PI3K/AKT activity in a CB2-dependent manner, and these effects were enhanced in the presence of osteolytic and osteoblastic factors such as RANKL (receptor activator of NFκB ligand) and parathyroid hormone. When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands depending upon cell type and concentration used. We, therefore, conclude that both CB2-selective activation and antagonism have potential efficacy in cancer-associated bone disease, but further studies are warranted and ongoing.

  16. Bone Cell-autonomous Contribution of Type 2 Cannabinoid Receptor to Breast Cancer-induced Osteolysis*

    PubMed Central

    Sophocleous, Antonia; Marino, Silvia; Logan, John G.; Mollat, Patrick; Ralston, Stuart H.; Idris, Aymen I.

    2015-01-01

    The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations. Under conditions in which these ligands are used at the nanomolar range, HU308 and JWH133 enhanced human and mouse breast cancer cell-induced osteoclastogenesis and exacerbated osteolysis, and these effects were attenuated in cultures obtained from CB2-deficient mice or in the presence of a CB2 receptor blocker. HU308 and JWH133 had no effects on osteoblast growth or differentiation in the presence of conditioned medium from breast cancer cells, but under these circumstances both agents enhanced parathyroid hormone-induced osteoblast differentiation and the ability to support osteoclast formation. Mechanistic studies in osteoclast precursors and osteoblasts showed that JWH133 and HU308 induced PI3K/AKT activity in a CB2-dependent manner, and these effects were enhanced in the presence of osteolytic and osteoblastic factors such as RANKL (receptor activator of NFκB ligand) and parathyroid hormone. When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands depending upon cell type and concentration used. We, therefore, conclude that both CB2-selective activation and antagonism have potential efficacy in cancer-associated bone disease, but further studies are warranted and ongoing. PMID:26195631

  17. Contribution of peripheral vanilloid receptor to the nociception induced by injection of spermine in mice.

    PubMed

    Gewehr, Camila; da Silva, Mariane Arnoldi; dos Santos, Gabriela Trevisan; Rossato, Mateus Fortes; de Oliveira, Sara Marchesan; Drewes, Carine Cristiane; Pazini, Andréia Martini; Guerra, Gustavo Petri; Rubin, Maribel A; Ferreira, Juliano

    2011-10-01

    Polyamines (putrescine, spermidine and spermine) are important endogenous regulators of ion channels, such as vanilloid (TRPV1), glutamatergic (NMDA or AMPA/kainate) and acid-sensitive (ASIC) receptors. In the present study, we have investigated the possible nociceptive effect induced by polyamines and the mechanisms involved in this nociception in vivo. The subcutaneous (s.c.) injection of capsaicin (as positive control), spermine, spermidine or putrescine produced nociception with ED(50) of 0.16 (0.07-0.39)nmol/paw, 0.4 (0.2-0.7) μmol/paw, 0.3 (0.1-0.9) μmol/paw and 3.2 (0.9-11.5) μmol/paw, respectively. The antagonists of NMDA (MK801, 1 nmol/paw), AMPA/kainate (DNQX, 1 nmol/paw) or ASIC receptors (amiloride, 100 nmol/paw) failed to reduce the spermine-trigged nociception. However, the TRPV1 antagonists capsazepine or SB366791 (1 nmol/paw) reduced spermine-induced nociception, with inhibition of 81 ± 10 and 68 ± 9%, respectively. The previous desensitization with resiniferatoxin (RTX) largely reduced the spermine-induced nociception and TRPV1 expression in the sciatic nerve, with reductions of 82 ± 9% and 67 ± 11%, respectively. Furthermore, the combination of spermine (100 nmol/paw) and RTX (0.005 fmol/paw), in doses which alone were not capable of inducing nociception, produced nociceptive behaviors. Moreover, different concentrations of spermine (3-300 μM) enhanced the specific binding of [(3)H]-RTX to TRPV1 receptor. Altogether, polyamines produce spontaneous nociceptive effect through the stimulation of TRPV1, but not of ionotropic glutamate or ASIC receptors.

  18. Contribution of a membrane estrogen receptor to the estrogenic regulation of body temperature and energy homeostasis.

    PubMed

    Roepke, Troy A; Bosch, Martha A; Rick, Elizabeth A; Lee, Benjamin; Wagner, Edward J; Seidlova-Wuttke, Dana; Wuttke, Wolfgang; Scanlan, Thomas S; Rønnekleiv, Oline K; Kelly, Martin J

    2010-10-01

    The hypothalamus is a key region of the central nervous system involved in the control of homeostasis, including energy and core body temperature (Tc). 17β-Estradiol (E2) regulates Tc, in part, via actions in the basal hypothalamus and preoptic area. E2 primarily controls hypothalamic functions via the nuclear steroid receptors, estrogen receptor α/β. However, we have previously described an E2-responsive, Gq-coupled membrane receptor that reduces the postsynaptic inhibitory γ-aminobutyric acid-ergic tone and attenuates postovariectomy body weight gain in female guinea pigs through the administration of a selective Gq-mER ligand, STX. To determine the role of Gq-mER in regulating Tc, energy and bone homeostasis, ovariectomized female guinea pigs, implanted ip with temperature probes, were treated with STX or E2 for 7-8 wk. Tc was recorded for 4 wk, whereas food intake and body weight were monitored daily. Bone density and fat accumulation were determined postmortem. Both E2 and STX significantly reduced Tc in the females compared with controls. STX, similar to E2, reduced food intake and fat accumulation and increased tibial bone density. Therefore, a Gq-mER-coupled signaling pathway appears to be involved in maintaining homeostatic functions and may constitute a novel therapeutic target for treatment of hypoestrogenic symptoms.

  19. Contribution of a Membrane Estrogen Receptor to the Estrogenic Regulation of Body Temperature and Energy Homeostasis

    PubMed Central

    Roepke, Troy A.; Bosch, Martha A.; Rick, Elizabeth A.; Lee, Benjamin; Wagner, Edward J.; Seidlova-Wuttke, Dana; Wuttke, Wolfgang; Scanlan, Thomas S.; Rønnekleiv, Oline K.; Kelly, Martin J.

    2010-01-01

    The hypothalamus is a key region of the central nervous system involved in the control of homeostasis, including energy and core body temperature (Tc). 17β-Estradiol (E2) regulates Tc, in part, via actions in the basal hypothalamus and preoptic area. E2 primarily controls hypothalamic functions via the nuclear steroid receptors, estrogen receptor α/β. However, we have previously described an E2-responsive, Gq-coupled membrane receptor that reduces the postsynaptic inhibitory γ-aminobutyric acid-ergic tone and attenuates postovariectomy body weight gain in female guinea pigs through the administration of a selective Gq-mER ligand, STX. To determine the role of Gq-mER in regulating Tc, energy and bone homeostasis, ovariectomized female guinea pigs, implanted ip with temperature probes, were treated with STX or E2 for 7–8 wk. Tc was recorded for 4 wk, whereas food intake and body weight were monitored daily. Bone density and fat accumulation were determined postmortem. Both E2 and STX significantly reduced Tc in the females compared with controls. STX, similar to E2, reduced food intake and fat accumulation and increased tibial bone density. Therefore, a Gq-mER-coupled signaling pathway appears to be involved in maintaining homeostatic functions and may constitute a novel therapeutic target for treatment of hypoestrogenic symptoms. PMID:20685867

  20. Serotonin receptors contribute to the promnesic effects of P. olacoides (Marapuama).

    PubMed

    da Silva, Adriana Lourenço; Ferreira, Juliana G; da Silva Martins, Bárbara; Oliveira, Sabrina; Mai, Nathalia; Nunes, Domingos S; Elisabetsky, Elaine

    2008-09-03

    Nootropic, antioxidant, and neuroprotective properties have been shown in a standardized ethanol extract of Ptychopetalum olacoides (POEE), a medicinal plant traditionally used by the Amazonian elderly population. It has been revealed that POEE mechanisms of action include anticholinesterase effects, and involve beta-adrenergic and dopamine D(1) receptors. The purpose of this study was to verify the role of serotonin receptors in the promnesic effects of this standardized extract. The step-down task in mice and selective serotonin antagonists were used. The study reveals that POEE promnesic effects on short-term (acquisition, consolidation and retrieval) and long-term (retrieval) declarative aversive memories are increased by 5HT(2A) (but not 5HT(1A)) serotonin antagonists (spiperone and pindolol, respectively). The observed synergism between POEE and spiperone can be interpreted as the combined effects of two subeffective doses of two 5HT antagonists, or the known synergism between an acetylcholinesterase inhibitor (POEE) and a 5HT antagonist. In conclusion it is suggested that 5HT(2A) serotonin receptors are relevant for the promnesic effects of this extract, adding to its multiple mechanisms of action.

  1. The Neurotensin Receptor-1 Pathway Contributes to Human Ductal Breast Cancer Progression

    PubMed Central

    Dupouy, Sandra; Viardot-Foucault, Véronique; Alifano, Marco; Souazé, Frédérique; Plu-Bureau, Geneviève; Chaouat, Marc; Lavaur, Anne; Hugol, Danielle; Gespach, Christian

    2009-01-01

    Background The neurotensin (NTS) and its specific high affinity G protein coupled receptor, the NT1 receptor (NTSR1), are considered to be a good candidate for one of the factors implicated in neoplastic progression. In breast cancer cells, functionally expressed NT1 receptor coordinates a series of transforming functions including cellular migration and invasion. Methods and Results we investigated the expression of NTS and NTSR1 in normal human breast tissue and in invasive ductal breast carcinomas (IDCs) by immunohistochemistry and RT-PCR. NTS is expressed and up-regulated by estrogen in normal epithelial breast cells. NTS is also found expressed in the ductal and invasive components of IDCs. The high expression of NTSR1 is associated with the SBR grade, the size of the tumor, and the number of metastatic lymph nodes. Furthermore, the NTSR1 high expression is an independent factor of prognosis associated with the death of patients. Conclusion these data support the activation of neurotensinergic deleterious pathways in breast cancer progression. PMID:19156213

  2. The Polyomaviridae: Contributions of virus structure to our understanding of virus receptors and infectious entry

    SciTech Connect

    Neu, Ursula; Stehle, Thilo Atwood, Walter J.

    2009-02-20

    This review summarizes the field's major findings related to the characterization of polyomavirus structures and to the characterization of virus receptors and mechanisms of host cell invasion. The four members of the family that have received the most attention in this regard are the mouse polyomavirus (mPyV), the monkey polyomavirus SV40, and the two human polyomaviruses, JCV and BKV. The structures of both the mPyV and SV40 alone and in complex with receptor fragments have been solved to high resolution. The majority of polyomaviruses recognize terminal sialic acid in either an {alpha}2,3 linkage or an {alpha}2,6 linkage to the underlying galactose. Studies on virus structure, receptor utilization and mechanisms of entry have led to new insights into how these viruses interact in an active way with cells to ensure the nuclear delivery and expression of their genomes. Critical work on virus entry has led to the discovery of a pH neutral endocytic compartment that accepts cargo from caveolae and to novel roles for endoplasmic reticulum (ER) associated factors in virus uncoating and penetration of ER membranes. This review will summarize the major findings and compare and contrast the mechanisms used by these viruses to infect cells.

  3. Dissociable hippocampal and amygdalar D1-like receptor contribution to discriminated Pavlovian conditioned approach learning.

    PubMed

    Andrzejewski, Matthew E; Ryals, Curtis

    2016-02-15

    Pavlovian conditioning is an elementary form of reward-related behavioral adaptation. The mesolimbic dopamine system is widely considered to mediate critical aspects of reward-related learning. For example, initial acquisition of positively-reinforced operant behavior requires dopamine (DA) D1 receptor (D1R) activation in the basolateral amygdala (BLA), central nucleus of the amygdala (CeA), and the ventral subiculum (vSUB). However, the role of D1R activation in these areas on appetitive, non-drug-related, Pavlovian learning is not currently known. In separate experiments, microinfusions of the D1-like receptor antagonist SCH-23390 (3.0 nmol/0.5 μL per side) into the amygdala and subiculum preceded discriminated Pavlovian conditioned approach (dPCA) training sessions. D1-like antagonism in all three structures impaired the acquisition of discriminated approach, but had no effect on performance after conditioning was asymptotic. Moreover, dissociable effects of D1-like antagonism in the three structures on components of discriminated responding were obtained. Lastly, the lack of latent inhibition in drug-treated groups may elucidate the role of D1-like in reward-related Pavlovian conditioning. The present data suggest a role for the D1 receptors in the amygdala and hippocampus in learning the significance of conditional stimuli, but not in the expression of conditional responses.

  4. Filovirus receptor NPC1 contributes to species-specific patterns of ebolavirus susceptibility in bats

    PubMed Central

    Ng, Melinda; Ndungo, Esther; Kaczmarek, Maria E; Herbert, Andrew S; Binger, Tabea; Kuehne, Ana I; Jangra, Rohit K; Hawkins, John A; Gifford, Robert J; Biswas, Rohan; Demogines, Ann; James, Rebekah M; Yu, Meng; Brummelkamp, Thijn R; Drosten, Christian; Wang, Lin-Fa; Kuhn, Jens H; Müller, Marcel A; Dye, John M; Sawyer, Sara L; Chandran, Kartik

    2015-01-01

    Biological factors that influence the host range and spillover of Ebola virus (EBOV) and other filoviruses remain enigmatic. While filoviruses infect diverse mammalian cell lines, we report that cells from African straw-colored fruit bats (Eidolon helvum) are refractory to EBOV infection. This could be explained by a single amino acid change in the filovirus receptor, NPC1, which greatly reduces the affinity of EBOV-NPC1 interaction. We found signatures of positive selection in bat NPC1 concentrated at the virus-receptor interface, with the strongest signal at the same residue that controls EBOV infection in Eidolon helvum cells. Our work identifies NPC1 as a genetic determinant of filovirus susceptibility in bats, and suggests that some NPC1 variations reflect host adaptations to reduce filovirus replication and virulence. A single viral mutation afforded escape from receptor control, revealing a pathway for compensatory viral evolution and a potential avenue for expansion of filovirus host range in nature. DOI: http://dx.doi.org/10.7554/eLife.11785.001 PMID:26698106

  5. GABA-A RECEPTOR ACTIVITY IN THE NORADRENERGIC LOCUS COERULEUS DRIVES TRIGEMINAL NEUROPATHIC PAIN IN THE RAT; CONTRIBUTION OF NAα1 RECEPTORS IN THE MEDIAL PREFRONTAL CORTEX

    PubMed Central

    KAUSHAL, R.; TAYLOR, B. K.; JAMAL, A. B.; ZHANG, L.; MA, F.; DONAHUE, R.; WESTLUND, K. N.

    2017-01-01

    Trigeminal neuropathic pain is described as constant excruciating facial pain. The study goal was to investigate the role of nucleus locus coeruleus (LC) in a model of chronic orofacial neuropathic pain (CCI-ION). The study examines LC’s relationship to both the medullary dorsal horn receiving trigeminal nerve sensory innervation and the medial prefrontal cortex (mPFC). LC is a major source of CNS noradrenaline (NA) and a primary nucleus involved in pain modulation. Although descending inhibition of acute pain by LC is well established, contribution of the LC to facilitation of chronic neuropathic pain is also reported. In the present study, a rat orofacial pain model of trigeminal neuropathy was induced by chronic constrictive injury of the infraorbital nerve (CCI-ION). Orofacial neuropathic pain was indicated by development of whisker pad mechanical hypersensitivity. Hypersensitivity was alleviated by selective elimination of NA neurons, including LC (A6 cell group), with the neurotoxin anti-dopamine-β-hydroxylase saporin (anti-DβH-saporin) microinjected either intracerebroventricularly (i.c.v.) or into trigeminal spinal nucleus caudalis (spVc). The GABAA receptor antagonist, bicuculline, administered directly into LC (week 8) inhibited hypersensitivity. This indicates a valence shift in which increased GABAA signaling ongoing in LC after trigeminal nerve injury paradoxically produces excitatory facilitation of the chronic pain state. Microinjection of NAα1 receptor antagonist, benoxathian, into mPFC attenuated whisker pad hypersensitivity, while NAα2 receptor antagonist, idazoxan, was ineffective. Thus, GABAA-mediated activation of NA neurons during CCI-ION can facilitate hypersensitivity through NAα1 receptors in the mPFC. These data indicate LC is a chronic pain generator. Published by Elsevier Ltd on behalf of IBRO. PMID:27520081

  6. NR2B-N-Methyl-D-Aspartate Receptors Contribute to Network Asynchrony and Loss of Long-Term Potentiation Following Mild Mechanical Injury In Vitro

    DTIC Science & Technology

    2012-08-30

    REPORT NR2B -N-METHYL-D-ASPARTATE RECEPTORS CONTRIBUTE TO NETWORK ASYNCHRONY AND LOSS OF LONG-TERM POTENTIATION FOLLOWING MILD MECHANICAL INJURY IN...integrate-and-fire model of network activity, 2) simulated an injured network, 3) predicted an important role for the NR2B -NMDA receptor in mediating...ADDRESSES U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS synchrony, NR2B -NMDA receptor, network

  7. The contribution of major histocompatibility complex contacts to the affinity and kinetics of T cell receptor binding

    PubMed Central

    Zhang, Hao; Lim, Hong-Sheng; Knapp, Berhard; Deane, Charlotte M.; Aleksic, Milos; Dushek, Omer; van der Merwe, P. Anton

    2016-01-01

    The interaction between the T cell antigen receptor (TCR) and antigenic peptide in complex with major histocompatibility complex (MHC) molecules is a crucial step in T cell activation. The relative contributions of TCR:peptide and TCR:MHC contacts to the overall binding energy remain unclear. This has important implications for our understanding of T cell development and function. In this study we used site directed mutagenesis to estimate the contribution of HLA-A2 side-chains to the binding of four TCRs. Our results show that these TCRs have very different energetic ‘footprints’ on HLA-A2, with no residues contributing to all TCR interactions. The estimated overall contribution of MHC side-chains to the total interaction energy was variable, with lower limits ranging from 11% to 50%. Kinetic analysis suggested a minor and variable contribution of MHC side-chains to the transition state complex, arguing against a two-step mechanism for TCR binding. PMID:27734930

  8. Glutamatergic contributions to nicotinic acetylcholine receptor agonist-evoked cholinergic transients in the prefrontal cortex.

    PubMed

    Parikh, Vinay; Man, Kingson; Decker, Michael W; Sarter, Martin

    2008-04-02

    Because modulation of cortical cholinergic neurotransmission has been hypothesized to represent a necessary mechanism mediating the beneficial cognitive effects of nicotine and nicotinic acetylcholine receptor (nAChR) subtype-selective agonists, we used choline-sensitive microelectrodes for the real-time measurement of ACh release in vivo, to characterize cholinergic transients evoked by nicotine and the alpha4beta2*-selective nAChR partial agonist 2-methyl-3-(2-(S)-pyrrolindinylmethoxy)pyridine dihydrochloride (ABT-089), a clinically effective cognition enhancer. In terms of cholinergic signal amplitudes, ABT-089 was significantly more potent than nicotine in evoking ACh cholinergic transients. Moreover, cholinergic signals evoked by ABT-089 were characterized by faster signal rise time and decay rate. The nAChR antagonist mecamylamine attenuated the cholinergic signals evoked by either compound. Cholinergic signals evoked by ABT-089 were more efficaciously attenuated by the relatively beta2*-selective nAChR antagonist dihydro-beta-erythroidine. The alpha7 antagonist methyllycaconitine did not affect choline signal amplitudes but partly attenuated the relatively slow decay rate of nicotine-evoked cholinergic signals. Furthermore, the AMPA receptor antagonist DNQX as well as the NMDA receptor antagonist APV more potently attenuated cholinergic signals evoked by ABT-089. Using glutamate-sensitive microelectrodes to measure glutamatergic transients, ABT-089 was more potent than nicotine in evoking glutamate release. Glutamatergic signals were highly sensitive to tetrodotoxin-induced blockade of voltage-regulated sodium channels. Together, the present evidence indicates that compared with nicotine, ABT-089 evokes more potent and sharper cholinergic transients in prefrontal cortex. Glutamatergic mechanisms necessarily mediate the cholinergic effects of nAChR agonists in the prefrontal cortex.

  9. Contribution of regional brain melanocortin receptor subtypes to elevated activity energy expenditure in lean, active rats

    PubMed Central

    Shukla, Charu; Koch, Lauren G.; Britton, Steven L.; Cai, Minying; Hruby, Victor J.; Bednarek, Maria; Novak, Colleen M.

    2015-01-01

    Physical activity and non-exercise activity thermogenesis (NEAT) are crucial factors accounting for individual differences in body weight, interacting with genetic predisposition. In the brain, a number of neuroendocrine intermediates regulate food intake and energy expenditure (EE); this includes the brain melanocortin (MC) system, consisting of melanocortin peptides as well as their receptors (MCR). MC3R and MC4R have emerged as critical modulators of EE and food intake. To determine how variance in MC signaling may underlie individual differences in physical activity levels, we examined behavioral response to MC receptor agonists and antagonists in rats that show high and low levels of physical activity and NEAT, that is, high- and low-capacity runners (HCR, LCR), developed by artificial selection for differential intrinsic aerobic running capacity. Focusing on the hypothalamus, we identified brain region-specific elevations in expression of MCR 3, 4, and also MC5R, in the highly active, lean HCR relative to the less active and obesity-prone LCR. Further, the differences in activity and associated EE as a result of MCR activation or suppression using specific agonists and antagonists were similarly region-specific and directly corresponded to the differential MCR expression patterns. The agonists and antagonists investigated here did not significantly impact food intake at the doses used, suggesting that the differential pattern of receptor expression may by more meaningful to physical activity than to other aspects of energy balance regulation. Thus, MCR-mediated physical activity may be a key neural mechanism in distinguishing the lean phenotype and a target for enhancing physical activity and NEAT. PMID:26404873

  10. Vitamin D and stress fracture: the contribution of vitamin D receptor gene polymorphisms.

    PubMed

    McClung, James P; Karl, J Philip

    2010-06-01

    Vitamin D is essential for optimal bone health. Stress fracture is an overuse injury often occurring in active populations. Study results indicate an association exists between vitamin D status and the risk of stress fracture, and one intervention trial demonstrated a reduction in stress fractures in women consuming supplemental vitamin D and calcium. A recent study found that two polymorphisms in the vitamin D receptor (VDR), Fok1 and Bsm1, may increase the risk of stress fracture. Although further study is required, screening for VDR polymorphisms may become a tool for identifying individuals at increased risk of stress fracture during physical training.

  11. The G2A receptor (GPR132) contributes to oxaliplatin-induced mechanical pain hypersensitivity.

    PubMed

    Hohmann, Stephan W; Angioni, Carlo; Tunaru, Sorin; Lee, Seungkyu; Woolf, Clifford J; Offermanns, Stefan; Geisslinger, Gerd; Scholich, Klaus; Sisignano, Marco

    2017-03-27

    Chemotherapy-induced peripheral neuropathic pain (CIPN) is a common and severe debilitating side effect of many widely used cytostatics. However, there is no approved pharmacological treatment for CIPN available. Among other substances, oxaliplatin causes CIPN in up to 80% of treated patients. Here, we report the involvement of the G-protein coupled receptor G2A (GPR132) in oxaliplatin-induced neuropathic pain in mice. We found that mice deficient in the G2A-receptor show decreased mechanical hypersensitivity after oxaliplatin treatment. Lipid ligands of G2A were found in increased concentrations in the sciatic nerve and dorsal root ganglia of oxaliplatin treated mice. Calcium imaging and patch-clamp experiments show that G2A activation sensitizes the ligand-gated ion channel TRPV1 in sensory neurons via activation of PKC. Based on these findings, we conclude that targeting G2A may be a promising approach to reduce oxaliplatin-induced TRPV1-sensitization and the hyperexcitability of sensory neurons and thereby to reduce pain in patients treated with this chemotherapeutic agent.

  12. Peripheral NMDA and non-NMDA receptors contribute to nociception: an electrophysiological study.

    PubMed

    Wang, C; Wang, Y; Zhao, Z

    2000-05-01

    The present study investigated the effects of peripheral administration of N-methy-D-aspartate (NMDA) and non-NMDA receptor antagonists on C-fiber evoked responses of the spinal dorsal horn neurons in the spinalized rats. When DL-2-amino-5-phosphonovaleric acid (AP5) (10 mM, 1 mM, 0.1 mM, 20 microl) or 6, 7-dinitroquinoxaline-2, 3-dione (DNQX) (1 mM, 0.1 mM, 0.01 mM, 20 microl) was subcutaneously injected into the receptive field on the hindplantar region, C-fiber evoked responses of the dorsal horn neurons were profoundly inhibited in a dose-dependent manner. Three hours after subcutaneous injection of carrageenan into the ipsilateral hindpaw, NMDA and non-NMDA antagonist-induced inhibition of C-fiber evoked responses was more potent than that in the normal rat (Student's t-test, p < 0.05). In the carragenan-treated rats, DNQX-induced inhibition was stronger than AP-5-induced one (Student's t-test, p < 0.05). The results suggest that peripheral NMDA and non-NMDA receptors are involved in mediating excitation of nociceptors.

  13. Dopamine D3 receptor antagonism contributes to blonanserin-induced cortical dopamine and acetylcholine efflux and cognitive improvement.

    PubMed

    Huang, Mei; Kwon, Sunoh; Oyamada, Yoshihiro; Rajagopal, Lakshmi; Miyauchi, Masanori; Meltzer, Herbert Y

    2015-11-01

    Blonanserin is a novel atypical antipsychotic drug (APD), which, unlike most atypical APDs, has a slightly higher affinity for dopamine (DA) D2 than serotonin (5-HT)2A receptors, and is an antagonist at both, as well as at D3 receptors. The effects of atypical APDs to enhance rodent cortical, hippocampal, limbic, and dorsal striatal (dSTR) DA and acetylcholine (ACh) release, contribute to their ability to improve novel object recognition (NOR) in rodents treated with sub-chronic (sc) phencyclidine (PCP) and cognitive impairment associated with schizophrenia (CIAS). Here we determined the ability of blonanserin, the D3 antagonist NGB 2904, and the typical APD, haloperidol, a D2 antagonist, to enhance neurotransmitter efflux in the medial prefrontal cortex (mPFC) and dSTR of mice, and to ameliorate the scPCP-induced deficit in NOR in rats. Blonanserin, 10mg/kg, i.p., increased DA, norepinephrine (NE), and ACh efflux in mPFC and dSTR. NGB 2904, 3mg/kg, increased DA and ACh, but not NE, efflux in mPFC, and DA, but not ACh, efflux in dSTR. Haloperidol increased DA and NE efflux in dSTR only. The selective D3 agonist PD 128907 partially blocked the blonanserin-induced cortical ACh, DA, NE and striatal DA efflux. NGB 2904, 3mg/kg, like blonanserin, 1mg/kg, and the combination of sub-effective doses of NGB 2904 and blonanserin (both 0.3mg/kg), ameliorated the scPCP-induced NOR deficit in rats. These results suggest that D3 receptor blockade may contribute to the ability of blonanserin to increase cortical DA and ACh efflux, as well as to restore NOR and improve CIAS.

  14. Contribution of P2X4 receptors to ethanol intake in male C57BL/6 mice

    PubMed Central

    Wyatt, Letisha R.; Finn, Deborah A.; Khoja, Sheraz; Yardley, Megan M; Asatryan, Liana; Alkana, Ronald L.; Davies, Daryl L.

    2014-01-01

    P2X receptors (P2XRs) are a family of cation-permeable ligand-gated ion channels activated by synaptically released extracellular ATP. The P2X4 subtype is abundantly expressed in the CNS and is sensitive to low intoxicating ethanol concentrations. Genetic meta-analyses identified the p2rx4 gene as a candidate gene for innate alcohol intake and/or preference. The current study used mice lacking the p2rx4 gene (knockout, KO) and wildtype (WT) C57BL/6 controls to test the hypothesis that P2X4Rs contribute to ethanol intake. The early acquisition and early maintenance phases of ethanol intake were measured with three different drinking procedures. Further, we tested the effects of ivermectin (IVM), a drug previously shown to reduce ethanol’s effects on P2X4Rs and to reduce ethanol intake and preference, for its ability to differentially alter stable ethanol intake in KO and WT mice. Depending on the procedure and the concentration of the ethanol solution, ethanol intake was transiently increased in P2X4R KO versus WT mice during the acquisition of 24-hr and limited access ethanol intake. IVM significantly reduced ethanol intake in P2X4R KO and WT mice, but the degree of reduction was 50% less in the P2X4R KO mice. Western blot analysis identified significant changes in -γ aminobutyric acidA receptor (GABAAR) α1 subunit expression in brain regions associated with the regulation of ethanol behaviors in P2X4R KO mice. These findings add to evidence that P2X4Rs contribute to ethanol intake and indicate that there is a complex interaction between P2X4Rs, ethanol, and other neurotransmitter receptor systems. PMID:24671605

  15. Contribution of P2X4 receptors to ethanol intake in male C57BL/6 mice.

    PubMed

    Wyatt, Letisha R; Finn, Deborah A; Khoja, Sheraz; Yardley, Megan M; Asatryan, Liana; Alkana, Ronald L; Davies, Daryl L

    2014-06-01

    P2X receptors (P2XRs) are a family of cation-permeable ligand-gated ion channels activated by synaptically released extracellular adenosine 5'-triphosphate. The P2X4 subtype is abundantly expressed in the central nervous system and is sensitive to low intoxicating ethanol concentrations. Genetic meta-analyses identified the p2rx4 gene as a candidate gene for innate alcohol intake and/or preference. The current study used mice lacking the p2rx4 gene (knockout, KO) and wildtype (WT) C57BL/6 controls to test the hypothesis that P2X4Rs contribute to ethanol intake. The early acquisition and early maintenance phases of ethanol intake were measured with three different drinking procedures. Further, we tested the effects of ivermectin (IVM), a drug previously shown to reduce ethanol's effects on P2X4Rs and to reduce ethanol intake and preference, for its ability to differentially alter stable ethanol intake in KO and WT mice. Depending on the procedure and the concentration of the ethanol solution, ethanol intake was transiently increased in P2X4R KO versus WT mice during the acquisition of 24-h and limited access ethanol intake. IVM significantly reduced ethanol intake in P2X4R KO and WT mice, but the degree of reduction was 50 % less in the P2X4R KO mice. Western blot analysis identified significant changes in γ-aminobutyric acidA receptor α1 subunit expression in brain regions associated with the regulation of ethanol behaviors in P2X4R KO mice. These findings add to evidence that P2X4Rs contribute to ethanol intake and indicate that there is a complex interaction between P2X4Rs, ethanol, and other neurotransmitter receptor systems.

  16. Differential Contribution of Kainate Receptors to EPSCs in Superficial Layer Neurons of the Rat Medial Entorhinal Cortex

    PubMed Central

    West, Peter J.; Dalpé-Charron, Alexandre; Wilcox, Karen S.

    2009-01-01

    Although in situ hybridization studies have revealed the presence of kainate receptor (KAR) mRNA in neurons of the rat medial entorhinal cortex (mEC), the functional presence and roles of these receptors are only beginning to be examined. To address this deficiency, whole cell voltage clamp recordings of locally evoked EPSCs were made from mEC layer II and III neurons in combined entorhinal cortex -hippocampal brain slices. Three types of neurons were identified by their electroresponsive membrane properties, locations, and morphologies: stellate-like “Sag” neurons in layer II (S), pyramidal-like “No Sag” neurons in layer III (NS), and “Intermediate Sag” neurons with varied morphologies and locations (IS). Non-NMDA EPSCs in these neurons were composed of two components, and the slow decay component in NS neurons had larger amplitudes and contributed more to the combined EPSC than did those observed in S and IS neurons. This slow component was mediated by KARs and was characterized by its resistance to either GYKI 52466 (100 μM) or NBQX (1 μM), relatively slow decay kinetics, and sensitivity to CNQX (10–50 μM). KAR mediated EPSCs in pyramidal-like NS neurons contributed significantly more to the combined non-NMDA EPSC than did those from S and IS neurons. Layer III neurons of the mEC are selectively susceptible to degeneration in human temporal lobe epilepsy (TLE) and animal models of TLE such as kainate-induced status epilepticus. Characterizing differences in the complement of postsynaptic receptors expressed in injury prone versus injury resistant mEC neurons represents an important step toward understanding the vulnerability of layer III neurons seen in TLE. PMID:17395391

  17. Differential contributions of vasopressin V1A and oxytocin receptors in the amygdala to pain-related behaviors in rats

    PubMed Central

    Cragg, Bryce; Ji, Guangchen

    2016-01-01

    Neuroplastic changes in the amygdala account for emotional-affective aspects of pain and involve neuropeptides such as calcitonin gene-related peptide and corticotropin-releasing factor. Another neuropeptide system, central arginine vasopressin, has been implicated in neuropsychiatric disorders, but its role in pain-related emotional expression and neuroplasticity remains to be determined. Here, we tested the hypothesis that arginine vasopressin in the amygdala contributes to pain-related emotional-affective responses, using stereotaxic applications of arginine vasopressin and antagonists for G-protein coupled vasopressin V1A and oxytocin receptors in adult male Sprague-Dawley rats. In normal animals, arginine vasopressin increased audible and ultrasonic vocalizations and anxiety-like behavior (decreased open-arm preference in the elevated plus maze). The facilitatory effects were blocked by a selective V1A antagonist (SR 49059, Relcovaptan) but not by an oxytocin receptor antagonist (L-371,257). L-371,257 had some facilitatory effects on vocalizations. Arginine vasopressin had no effect in arthritic rats (kaolin/carrageenan knee joint pain model). SR 49059 inhibited vocalizations and anxiety-like behavior (elevated plus maze) in arthritic, but not normal, rats and conveyed anxiolytic properties to arginine vasopressin. Arginine vasopressin, SR 49059, and L-371,257 had no significant effects on spinal reflexes. We interpret the data to suggest that arginine vasopressin through V1A in the amygdala contributes to emotional-affective aspects of pain (arthritis model), whereas oxytocin receptors may mediate some inhibitory effects of the vasopressin system. PMID:27837170

  18. Contribution of different classes of glutamate receptors in the corticostriatal polysynaptic responses from striatal direct and indirect projection neurons

    PubMed Central

    2013-01-01

    responses that contribute to plateau depolarizations. Conclusions As it has been established in previous physiological studies in vivo, synaptic invasion over different latencies, spanning hundreds of milliseconds after a single stimulus strongly indicates convergent polysynaptic activation. Interconnected cortical neurons converging on the same SPNs may explain prolonged corticostriatal responses. Glutamate receptors participation in these responses is described as well as differences and similarities between dSPNs and iSPNs. PMID:23782743

  19. The Receptor for Advanced Glycation End Products (RAGE) Contributes to the Progression of Emphysema in Mice

    PubMed Central

    Sambamurthy, Nisha; Leme, Adriana S.; Oury, Tim D.; Shapiro, Steven D.

    2015-01-01

    Several recent clinical studies have implied a role for the receptor for advanced glycation end products (RAGE) and its variants in chronic obstructive pulmonary disease (COPD). In this study we have defined a role for RAGE in the pathogenesis of emphysema in mice. RAGE deficient mice (RAGE-/-) exposed to chronic cigarette smoke were significantly protected from smoke induced emphysema as determined by airspace enlargement and had no significant reduction in lung tissue elastance when compared to their air exposed controls contrary to their wild type littermates. The progression of emphysema has been largely attributed to an increased inflammatory cell-mediated elastolysis. Acute cigarette smoke exposure in RAGE-/- mice revealed an impaired early recruitment of neutrophils, approximately a 6-fold decrease compared to wild type mice. Hence, impaired neutrophil recruitment with continued cigarette smoke exposure reduces elastolysis and consequent emphysema. PMID:25781626

  20. IKKϵ Phosphorylation of Estrogen Receptor α Ser-167 and Contribution to Tamoxifen Resistance in Breast Cancer*

    PubMed Central

    Guo, Jian-Ping; Shu, Shao-Kun; Esposito, Nicole N.; Coppola, Domenico; Koomen, John M.; Cheng, Jin Q.

    2010-01-01

    IKKϵ has recently been identified as a breast cancer oncogene. Elevated levels of IKKϵ are associated with cell survival and growth. Here, we show that IKKϵ interacts with and phosphorylates estrogen receptor α (ERα) on serine 167 in vitro and in vivo. As a result, IKKϵ induces ERα transactivation activity and enhances ERα binding to DNA. Cyclin D1, a major target of ERα, is transcriptionally up-regulated by IKKϵ in a phospho-ERα-Ser-167-dependent manner. Further, overexpression of IKKϵ induces tamoxifen resistance, whereas knockdown of IKKϵ sensitizes cells to tamoxifen-induced cell death. These data suggest that ERα is a bona fide substrate of IKKϵ and IKKϵ plays an important role in tamoxifen resistance. Thus, IKKϵ represents a critical therapeutic target in breast cancer. PMID:19940156

  1. Dissociation between neural and vascular responses to sympathetic stimulation : contribution of local adrenergic receptor function

    NASA Technical Reports Server (NTRS)

    Jacob, G.; Costa, F.; Shannon, J.; Robertson, D.; Biaggioni, I.

    2000-01-01

    Sympathetic activation produced by various stimuli, eg, mental stress or handgrip, evokes regional vascular responses that are often nonhomogeneous. This phenomenon is believed to be the consequence of the recruitment of differential central neural pathways or of a sympathetically mediated vasodilation. The purpose of this study was to determine whether a similar heterogeneous response occurs with cold pressor stimulation and to test the hypothesis that local differences in adrenergic receptor function could be in part responsible for this diversity. In 8 healthy subjects, local norepinephrine spillover and blood flow were measured in arms and legs at baseline and during sympathetic stimulation induced by baroreflex mechanisms (nitroprusside infusion) or cold pressor stimulation. At baseline, legs had higher vascular resistance (27+/-5 versus 17+/-2 U, P=0.05) despite lower norepinephrine spillover (0.28+/-0.04 versus 0.4+/-0.05 mg. min(-1). dL(-1), P=0.03). Norepinephrine spillover increased similarly in both arms and legs during nitroprusside infusion and cold pressor stimulation. On the other hand, during cold stimulation, vascular resistance increased in arms but not in legs (20+/-9% versus -7+/-4%, P=0.03). Increasing doses of isoproterenol and phenylephrine were infused intra-arterially in arms and legs to estimate beta-mediated vasodilation and alpha-induced vasoconstriction, respectively. beta-Mediated vasodilation was significantly lower in legs compared with arms. Thus, we report a dissociation between norepinephrine spillover and vascular responses to cold stress in lower limbs characterized by a paradoxical decrease in local resistance despite increases in sympathetic activity. The differences observed in adrenergic receptor responses cannot explain this phenomenon.

  2. Insulin Receptor Substrate-1 Associates with Small Nucleolar RNA Which Contributes to Ribosome Biogenesis

    PubMed Central

    Ozoe, Atsufumi; Sone, Meri; Fukushima, Toshiaki; Kataoka, Naoyuki; Chida, Kazuhiro; Asano, Tomoichiro; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

    2014-01-01

    Insulin receptor substrates (IRSs) are well known to play crucial roles in mediating intracellular signals of insulin-like growth factors (IGFs)/insulin. Previously, we showed that IRS-1 forms high molecular mass complexes containing RNAs. To identify RNAs in IRS-1 complexes, we performed ultraviolet (UV) cross-linking and immunoprecipitation analysis using HEK293 cells expressing FLAG–IRS-1 and FLAG–IRS-2. We detected the radioactive signals in the immunoprecipitates of FLAG–IRS-1 proportional to the UV irradiation, but not in the immunoprecipitates of FLAG–IRS-2, suggesting the direct contact of RNAs with IRS-1. RNAs cross-linked to IRS-1 were then amplified by RT-PCR, followed by sequence analysis. We isolated sequence tags attributed to 25 messenger RNAs and 8 non-coding RNAs, including small nucleolar RNAs (snoRNAs). We focused on the interaction of IRS-1 with U96A snoRNA (U96A) and its host Rack1 (receptor for activated C kinase 1) pre-mRNA. We confirmed the interaction of IRS-1 with U96A, and with RACK1 pre-mRNA by immunoprecipitation with IRS-1 followed by Northern blotting or RT-PCR analyses. Mature U96A in IRS-1−/− mouse embryonic fibroblasts was quantitatively less than WT. We also found that a part of nuclear IRS-1 is localized in the Cajal body, a nuclear subcompartment where snoRNA mature. The unanticipated function of IRS-1 in snoRNA biogenesis highlights the potential of RNA-associated IRS-1 complex to open a new line of investigation to dissect the novel mechanisms regulating IGFs/insulin-mediated biological events. PMID:24624118

  3. MHC-Linked Olfactory Receptor Loci Exhibit Polymorphism and Contribute to Extended HLA/OR-Haplotypes

    PubMed Central

    Ehlers, Anke; Beck, Stephan; Forbes, Simon A.; Trowsdale, John; Volz, Armin; Younger, Ruth; Ziegler, Andreas

    2000-01-01

    Clusters of olfactory receptor (OR) genes are found on most human chromosomes. They are one of the largest mammalian multigene families. Here, we report a systematic study of polymorphism of OR genes belonging to the largest fully sequenced OR cluster. The cluster contains 36 OR genes, of which two belong to the vomeronasal 1 (V1-OR) family. The cluster is divided into a major and a minor region at the telomeric end of the HLA complex on chromosome 6. These OR genes could be involved in MHC-related mate preferences. The polymorphism screen was carried out with 13 genes from the HLA-linked OR cluster and three genes from chromosomes 7, 17, and 19 as controls. Ten human cell lines, representing 18 different chromosome 6s, were analyzed. They were from various ethnic origins and exhibited different HLA haplotypes. All OR genes tested, including those not linked to the HLA complex, were polymorphic. These polymorphisms were dispersed along the coding region and resulted in up to seven alleles for a given OR gene. Three polymorphisms resulted either in stop codons (genes hs6M1-4P, hs6M1-17) or in a 16–bp deletion (gene hs6M1-19P), possibly leading to lack of ligand recognition by the respective receptors in the cell line donors. In total, 13 HLA-linked OR haplotypes could be defined. Therefore, allelic variation appears to be a general feature of human OR genes. [The sequence data reported in this paper have been submitted to EMBL under accession nos. AC006137, AC004178, AJ132194, AL022727, AL031983, AL035402, AL035542, Z98744, CAB55431, AL050339, AL035402, AL096770, AL133267, AL121944, Z98745, AL021808, and AL021807.] PMID:11116091

  4. Adenosine A1 receptors contribute to immune regulation after neonatal hypoxic ischemic brain injury.

    PubMed

    Winerdal, Max; Winerdal, Malin E; Wang, Ying-Qing; Fredholm, Bertil B; Winqvist, Ola; Ådén, Ulrika

    2016-03-01

    Neonatal brain hypoxic ischemia (HI) often results in long-term motor and cognitive impairments. Post-ischemic inflammation greatly effects outcome and adenosine receptor signaling modulates both HI and immune cell function. Here, we investigated the influence of adenosine A1 receptor deficiency (A1R(-/-)) on key immune cell populations in a neonatal brain HI model. Ten-day-old mice were subjected to HI. Functional outcome was assessed by open locomotion and beam walking test and infarction size evaluated. Flow cytometry was performed on brain-infiltrating cells, and semi-automated analysis of flow cytometric data was applied. A1R(-/-) mice displayed larger infarctions (+33%, p < 0.05) and performed worse in beam walking tests (44% more mistakes, p < 0.05) than wild-type (WT) mice. Myeloid cell activation after injury was enhanced in A1R(-/-) versus WT brains. Activated B lymphocytes expressing IL-10 infiltrated the brain after HI in WT, but were less activated and did not increase in relative frequency in A1R(-/-). Also, A1R(-/-) B lymphocytes expressed less IL-10 than their WT counterparts, the A1R antagonist DPCPX decreased IL-10 expression whereas the A1R agonist CPA increased it. CD4(+) T lymphocytes including FoxP3(+) T regulatory cells, were unaffected by genotype, whereas CD8(+) T lymphocyte responses were smaller in A1R(-/-) mice. Using PCA to characterize the immune profile, we could discriminate the A1R(-/-) and WT genotypes as well as sham operated from HI-subjected animals. We conclude that A1R signaling modulates IL-10 expression by immune cells, influences the activation of these cells in vivo, and affects outcome after HI.

  5. Racially restricted contribution of immunoglobulin Fcγ and Fcγ receptor genotypes to humoral immunity to human epidermal growth factor receptor 2 in breast cancer.

    PubMed

    Pandey, J P; Namboodiri, A M; Kistner-Griffin, E; Iwasaki, M; Kasuga, Y; Hamada, G S; Tsugane, S

    2013-03-01

    Tumour-associated antigen human epidermal growth factor receptor 2 (HER2) is over-expressed in 25-30% of breast cancer patients and is associated with poor prognosis. Naturally occurring anti-HER2 antibody responses have been described in patients with HER2 over-expressing tumours. There is significant interindividual variability in antibody responsiveness, but the host genetic factors responsible for this variability are poorly understood. The aim of the present investigation was to determine whether immunoglobulin genetic markers [GM (genetic determinants of γ chains)] and Fcγ receptor (FcγR) alleles contribute to the magnitude of natural antibody responsiveness to HER2 in patients with breast cancer. A total of 855 breast cancer patients from Japan and Brazil were genotyped for several GM and FcγR alleles. They were also characterized for immunoglobulin (Ig)G antibodies to HER2. In white subjects (n = 263), GM 23-carriers had higher levels of anti-HER2 antibodies than non-carriers of this allele (p = 0·004). At the GM 5/21 locus, the homozygotes for the GM 5 allele had higher levels of anti-HER2 antibodies than the other two genotypes (P = 0·0067). In black subjects (n = 42), FcγRIIa-histidine/histidine homozygotes and FcγRIIIa-phenylalanine/valine heterozygotes were associated with high antibody responses (P = 0·0071 and 0·0275, respectively). FcγR genotypes in white subjects and GM genotypes in black subjects were not associated with anti-HER2 antibody responses. No significant associations were found in other study groups. These racially restricted contributions of GM and FcγR genotypes to humoral immunity to HER2 have potential implications for immunotherapy of breast cancer.

  6. Distinct Contributions of T1R2 and T1R3 Taste Receptor Subunits to the Detection of Sweet Stimuli

    SciTech Connect

    Nie,Y.; Vigues, S.; Hobbs, J.; Conn, G.; Munger, S.

    2005-01-01

    The molecular mechanisms by which G protein-coupled receptor (GPCR)-type chemosensory receptors of animals selectively interact with their cognate ligands remain poorly understood. There is growing evidence that many chemosensory receptors exist in multimeric complexes, though little is known about the relative contributions of individual subunits to receptor functions. This study showed that each of the two subunits in the mammalian heteromeric T1R2:T1R3 sweet taste receptor binds sweet stimuli, though with distinct affinities and conformational changes. Furthermore, ligand affinities for T1R3 are drastically reduced by the introduction of a single amino acid change associated with decreased sweet taste sensitivity in mice. Thus, individual T1R subunits increase the receptive range of the sweet taste receptor, offering a functional mechanism for phenotypic variations in sweet taste.

  7. Dibutyl phthalate contributes to the thyroid receptor antagonistic activity in drinking water processes.

    PubMed

    Li, Na; Wang, Donghong; Zhou, Yiqi; Ma, Mei; Li, Jian; Wang, Zijian

    2010-09-01

    It has long been recognized that thyroid hormone (TH) is essential for normal brain development in both humans and animals, and there is growing evidence that environmental chemicals can disrupt the thyroid system. In the present work, we used a two-hybrid yeast assay to screen for agonistic or antagonistic thyroid receptor (TR) mediated effects in drinking waters. We found no TR agonistic, but TR antagonistic activities in all samples from the drinking water processes. The TR antagonistic activities in organic extracts of water samples were then calibrated regarding to a known TR-inhibitor, NH3, and were expressed as the NH3 equivalents (TEQbio). The observed TEQbio in waters ranged from 180.8+/-24.8 to 280.2+/-48.2 microg/L NH3. To identify the specific compounds responsible for TR disrupting activities, the concentrations of potentially thyroid-disrupting chemicals including organochlorine pesticides (OCPs), phenols, and phthalates in organic extracts were quantitatively determined and their toxic equivalents with respect to NH3 (TEQcal) were estimated from their concentration-dependent relationships, respectively, using the same set of bioassays. Based on the TEQ approach, it was revealed that dibutyl phthalate (DBP) accounted for 53.7+/-8.2% to 105.5+/-16.7% of TEQbio. There was no effective removal of these potential thyroid disrupting substances throughout drinking water treatment processes.

  8. Metalloproteinase-9 contributes to endothelial dysfunction in atherosclerosis via protease activated receptor-1

    PubMed Central

    Florence, Jon M.; Booshehri, Laela M.; Allen, Timothy C.; Kurdowska, Anna K.

    2017-01-01

    The atherosclerotic process begins when vascular endothelial cells undergo pro-inflammatory changes such as aberrant activation to dysfunctional phenotypes and apoptosis, leading to loss of vascular integrity. Our laboratory has demonstrated that exposure of mice to second hand smoke triggers an increase in expression of metalloproteinase-9. Further, metalloproteinase-9 released by second hand smoke—activated leukocytes may propagate pro-atherogenic alterations in endothelial cells. We have shown that levels of metalloproteinase-9 were increased in the plasma from apolipoprotein E deficient (ApoE-/-) mice exposed to second hand smoke relative to non-exposed controls. Moreover, we have collected data from two different, but complementary, treatments of second hand smoke exposed atherosclerotic mice. Animals received either cell specific metalloproteinase-9 directed siRNA to minimize metalloproteinase-9 expression in neutrophils and endothelial cells, or a pharmacological inhibitor of Bruton’s tyrosine kinase which indirectly limits metalloproteinase-9 production in neutrophils. These treatments reduced atherosclerotic changes in mice and improved overall vascular health. We also demonstrated that metalloproteinase-9 could activate endothelial cells and induce their apoptosis via cleavage of protease activated receptor-1. In summary, better understanding of metalloproteinase-9’s pathogenic capabilities as well as novel signaling pathways involved may lead to development of treatments which may provide additional benefits to atherosclerosis patients with a history of second hand smoke exposure. PMID:28166283

  9. Adiponectin and its receptors: partners contributing to the "vicious circle" leading to the metabolic syndrome?

    PubMed

    Vasseur, Francis

    2006-06-01

    Although already described five years ago, it is only from year 2000, following intensive research in the field of genetics that the adiponectin protein was related with insulin sensitivity, type 2 diabetes and the metabolic syndrome. The story began with a paradox as this protein exclusively secreted by fat tissue was dramatically decreased in patients presenting an excess of fat mass. Later this decrease was reported with insulin resistance and metabolic syndrome associated phenotypes. The search for genetic variants in the adiponectin encoding ACDC gene and epidemio genetic investigations allowed to associate genetic variations of the gene and phenotypic traits of the metabolic syndrome. One of the major points was the correlation of the levels of circulating adiponectin with insulin sensitivity, leading to a better knowledge of the role of adiponectin. Indeed it is now clearly admitted that adiponectin is an insulin sensitizing cytokine. Recently two adiponectin receptors were described and genetic variations in their genes were associated with features of the metabolic syndrome. Interactions of adiponectin with various partners are discussed in view of a better understanding of adiponectin resistance and insulin resistance.

  10. Toll-like receptor 4-dependent contribution of the immune system to anticancer chemotherapy and radiotherapy.

    PubMed

    Apetoh, Lionel; Ghiringhelli, François; Tesniere, Antoine; Obeid, Michel; Ortiz, Carla; Criollo, Alfredo; Mignot, Grégoire; Maiuri, M Chiara; Ullrich, Evelyn; Saulnier, Patrick; Yang, Huan; Amigorena, Sebastian; Ryffel, Bernard; Barrat, Franck J; Saftig, Paul; Levi, Francis; Lidereau, Rosette; Nogues, Catherine; Mira, Jean-Paul; Chompret, Agnès; Joulin, Virginie; Clavel-Chapelon, Françoise; Bourhis, Jean; André, Fabrice; Delaloge, Suzette; Tursz, Thomas; Kroemer, Guido; Zitvogel, Laurence

    2007-09-01

    Conventional cancer treatments rely on radiotherapy and chemotherapy. Such treatments supposedly mediate their effects via the direct elimination of tumor cells. Here we show that the success of some protocols for anticancer therapy depends on innate and adaptive antitumor immune responses. We describe in both mice and humans a previously unrecognized pathway for the activation of tumor antigen-specific T-cell immunity that involves secretion of the high-mobility-group box 1 (HMGB1) alarmin protein by dying tumor cells and the action of HMGB1 on Toll-like receptor 4 (TLR4) expressed by dendritic cells (DCs). During chemotherapy or radiotherapy, DCs require signaling through TLR4 and its adaptor MyD88 for efficient processing and cross-presentation of antigen from dying tumor cells. Patients with breast cancer who carry a TLR4 loss-of-function allele relapse more quickly after radiotherapy and chemotherapy than those carrying the normal TLR4 allele. These results delineate a clinically relevant immunoadjuvant pathway triggered by tumor cell death.

  11. Death receptor 6 contributes to autoimmunity in lupus-prone mice

    PubMed Central

    Fujikura, Daisuke; Ikesue, Masahiro; Endo, Tsutomu; Chiba, Satoko; Higashi, Hideaki; Uede, Toshimitsu

    2017-01-01

    Expansion of autoreactive follicular helper T (Tfh) cells is tightly restricted to prevent induction of autoantibody-dependent immunological diseases, such as systemic lupus erythematosus (SLE). Here we show expression of an orphan immune regulator, death receptor 6 (DR6/TNFRSF21), on a population of Tfh cells that are highly expanded in lupus-like disease progression in mice. Genome-wide screening reveals an interaction between syndecan-1 and DR6 resulting in immunosuppressive functions. Importantly, syndecan-1 is expressed specifically on autoreactive germinal centre (GC) B cells that are critical for maintenance of Tfh cells. Syndecan-1 expression level on GC B cells is associated with Tfh cell expansion and disease progression in lupus-prone mouse strains. In addition, Tfh cell suppression by DR6-specific monoclonal antibody delays disease progression in lupus-prone mice. These findings suggest that the DR6/syndecan-1 axis regulates aberrant GC reactions and could be a therapeutic target for autoimmune diseases such as SLE. PMID:28045014

  12. Contribution of α7 nicotinic receptor to airway epithelium dysfunction under nicotine exposure.

    PubMed

    Maouche, Kamel; Medjber, Kahina; Zahm, Jean-Marie; Delavoie, Franck; Terryn, Christine; Coraux, Christelle; Pons, Stéphanie; Cloëz-Tayarani, Isabelle; Maskos, Uwe; Birembaut, Philippe; Tournier, Jean-Marie

    2013-03-05

    Loss or dysfunction of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) leads to impairment of airway mucus transport and to chronic lung diseases resulting in progressive respiratory failure. Nicotinic acetylcholine receptors (nAChRs) bind nicotine and nicotine-derived nitrosamines and thus mediate many of the tobacco-related deleterious effects in the lung. Here we identify α7 nAChR as a key regulator of CFTR in the airways. The airway epithelium in α7 knockout mice is characterized by a higher transepithelial potential difference, an increase of amiloride-sensitive apical Na(+) absorption, a defective cAMP-dependent Cl(-) conductance, higher concentrations of Na(+), Cl(-), K(+), and Ca(2+) in secretions, and a decreased mucus transport, all relevant to a deficient CFTR activity. Moreover, prolonged nicotine exposure mimics the absence of α7 nAChR in mice or its inactivation in vitro in human airway epithelial cell cultures. The functional coupling of α7 nAChR to CFTR occurs through Ca(2+) entry and activation of adenylyl cyclases, protein kinase A, and PKC. α7 nAChR, CFTR, and adenylyl cyclase-1 are physically and functionally associated in a macromolecular complex within lipid rafts at the apical membrane of surface and glandular airway epithelium. This study establishes the potential role of α7 nAChR in the regulation of CFTR function and in the pathogenesis of smoking-related chronic lung diseases.

  13. The moderating role of an oxytocin receptor gene polymorphism in the relation between unsupportive social interactions and coping profiles: implications for depression

    PubMed Central

    McInnis, Opal A.; McQuaid, Robyn J.; Matheson, Kimberly; Anisman, Hymie

    2015-01-01

    Oxytocin is a hormone that is thought to influence prosocial behaviors and may be important in modulating responses to both positive and negative social interactions. Indeed, a single nucleotide polymorphism, rs53576, of the oxytocin receptor gene (OXTR) has been associated with decreased trust, empathy, optimism, and social support seeking, which are important components of coping with stressors. In the current study, conducted among undergraduate students (N = 225), it was shown that parental and peer social support was related to fewer depressive symptoms through elevated problem-focused coping and lower emotion-focused coping, and these effects were independent of the OXTR polymorphism. Unsupportive social interactions from parents were associated with more severe depressive symptoms through the greater use of emotion-focused coping, and this relation was moderated by the OXTR genotype. Specifically, individuals who carried the polymorphism on one or both of their alleles demonstrated increased emotion-focused coping following unsupportive responses compared to those without the polymorphism. Likewise, lower problem-focused coping mediated the relation between parental and peer unsupportive responses to depressive symptoms, but this mediated relation was only evident among carriers of the polymorphism. These findings suggest that carrying this OXTR polymorphism might favor disadvantageous coping styles in the face of negative social interactions, which in turn are linked to poor mood. Regardless of genotype, parental, and peer social support are fundamental in determining stress-related coping and well-being. PMID:26321972

  14. VOC emissions, evolutions and contributions to SOA formation at a receptor site in eastern China

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Hu, W. W.; Shao, M.; Wang, M.; Chen, W. T.; Lu, S. H.; Zeng, L. M.; Hu, M.

    2013-09-01

    Volatile organic compounds (VOCs) were measured by two online instruments (GC-FID/MS and PTR-MS) at a receptor site on Changdao Island (37.99° N, 120.70° E) in eastern China. Reaction with OH radical dominated chemical losses of most VOC species during the Changdao campaign. A photochemical-age-based parameterization method is used to calculate VOC emission ratios and to quantify the evolution of ambient VOCs. The calculated emission ratios of most hydrocarbons agree well with those obtained from emission inventory data, but determined emission ratios of oxygenated VOCs (OVOCs) are significantly higher than those from emission inventory data. The photochemical-age-based parameterization method is also used to investigate primary emissions and secondary formation of organic aerosol. The primary emission ratio of organic aerosol (OA) to CO is determined to be 14.9 μg m-3 ppm-1, and secondary organic aeorosols (SOA) are produced at an enhancement ratio of 18.8 μg m-3 ppm-1 to CO after 50 h of photochemical processing in the atmosphere. SOA formation is significantly higher than the level determined from VOC oxidation under both high-NOx (2.0 μg m-3 ppm-1 CO) and low-NOx conditions (6.5 μg m-3 ppm-1 CO). Polycyclic aromatic hydrocarbons (PAHs) and higher alkanes (> C10) account for as high as 17.4% of SOA formation, which suggests semi-volatile organic compounds (SVOCs) may be a large contributor to SOA formation during the Changdao campaign. The SOA formation potential of primary VOC emissions determined from field campaigns in Beijing and Pearl River Delta (PRD) is lower than the measured SOA levels reported in the two regions, indicating SOA formation is also beyond explainable by VOC oxidation in the two city clusters.

  15. Activation of Renal (Pro)Renin Receptor Contributes to High Fructose-Induced Salt Sensitivity.

    PubMed

    Xu, Chuanming; Lu, Aihua; Lu, Xiaohan; Zhang, Linlin; Fang, Hui; Zhou, Li; Yang, Tianxin

    2017-02-01

    A high-fructose diet is shown to induce salt-sensitive hypertension, but the underlying mechanism largely remains unknown. The major goal of the present study was to test the role of renal (pro)renin receptor (PRR) in this model. In Sprague-Dawley rats, high-fructose intake increased renal expression of full-length PRR, which were attenuated by allopurinol. High-fructose intake also upregulated renal mRNA and protein expression of sodium/hydrogen exchanger 3 and Na/K/2Cl cotransporter, as well as in vivo Na/K/2Cl cotransporter activity, all of which were nearly completely blocked by a PRR decoy inhibitor PRO20 or allopurinol treatment. Parallel changes were observed for indices of intrarenal renin-angiotensin-system including renal and urinary renin and angiotensin II levels. Radiotelemetry demonstrated that high-fructose or a high-salt diet alone did not affect mean arterial pressure, but the combination of the 2 maneuvers induced a ≈10-mm Hg increase of mean arterial pressure, which was blunted by PRO20 or allopurinol treatment. In cultured human kidney 2 cells, both fructose and uric acid increased protein expression of soluble PRR in a time- and dose-dependent manner; fructose-induced PRR upregulation was inhibited by allopurinol. Taken together, our data suggest that fructose via uric acid stimulates renal expression of PRR/soluble PRR that stimulate sodium/hydrogen exchanger 3 and Na/K/2Cl cotransporter expression and intrarenal renin-angiotensin system to induce salt-sensitive hypertension.

  16. The aryl hydrocarbon receptor contributes to the proliferation of human medulloblastoma cells.

    PubMed

    Dever, Daniel P; Opanashuk, Lisa A

    2012-05-01

    The aryl hydrocarbon receptor (AhR), a ligand-activated member of the basic helix-loop-helix (bHLH)/PER-ARNT-SIM (PAS) transcription superfamily, is known to regulate the toxicity of polyaromatic halogenated hydrocarbon environmental chemicals, most notably dioxin. However, the AhR has also been implicated in multiple stages of tumorigenesis. Medulloblastoma (MB), a primary cerebellar brain tumor arising in infants and children, is thought to originate from abnormally proliferating cerebellar granule neuron precursors (GNPs). GNPs express high levels of the AhR in the external germinal layer of the developing cerebellum. Moreover, our laboratory has previously reported that either abnormal activation or deletion of the AhR leads to dysregulation of GNP cell cycle activity and maturation. These observations led to the hypothesis that the AhR promotes the growth of MB. Therefore, this study evaluated whether the AhR serves a pro-proliferative role in an immortalized MB tumor cell line (DAOY). We produced a stable AhR knockdown DAOY cell line [AhR short hairpin RNA (shRNA)], which exhibited a 70% reduction in AhR protein levels. Compared with wild-type DAOY cells, AhR shRNA DAOY cells displayed an impaired G(1)-to-S cell cycle transition, decreased DNA synthesis, and reduced proliferation. Furthermore, these cell cycle perturbations were correlated with decreased levels of the pro-proliferative gene Hes1 and increased levels of the cell cycle inhibitor p27(kip1). Supplementation experiments with human AhR restored the proliferative activity in AhR shRNA DAOY cells. Taken together, our data show that the AhR promotes proliferation of MB cells, suggesting that this pathway should be considered as a potential therapeutic target for MB treatment.

  17. Investigations of the contribution of a putative glycine hinge to ryanodine receptor channel gating.

    PubMed

    Euden, Joanne; Mason, Sammy A; Viero, Cedric; Thomas, N Lowri; Williams, Alan J

    2013-06-07

    Ryanodine receptor channels (RyR) are key components of striated muscle excitation-contraction coupling, and alterations in their function underlie both inherited and acquired disease. A full understanding of the disease process will require a detailed knowledge of the mechanisms and structures involved in RyR function. Unfortunately, high-resolution structural data, such as exist for K(+)-selective channels, are not available for RyR. In the absence of these data, we have used modeling to identify similarities in the structural elements of K(+) channel pore-forming regions and postulated equivalent regions of RyR. This has identified a sequence of residues in the cytosolic cavity-lining transmembrane helix of RyR (G(4864)LIIDA(4869) in RyR2) analogous to the glycine hinge motif present in many K(+) channels. Gating in these K(+) channels can be disrupted by substitution of residues for the hinge glycine. We investigated the involvement of glycine 4864 in RyR2 gating by monitoring properties of recombinant human RyR2 channels in which this glycine is replaced by residues that alter gating in K(+) channels. Our data demonstrate that introducing alanine at position 4864 produces no significant change in RyR2 function. In contrast, function is altered when glycine 4864 is replaced by either valine or proline, the former preventing channel opening and the latter modifying both ion translocation and gating. Our studies reveal novel information on the structural basis of RyR gating, identifying both similarities with, and differences from, K(+) channels. Glycine 4864 is not absolutely required for channel gating, but some flexibility at this point in the cavity-lining transmembrane helix is necessary for normal RyR function.

  18. The ryanodine receptor is expressed in human pancreatic acinar cells and contributes to acinar cell injury.

    PubMed

    Lewarchik, Christopher M; Orabi, Abrahim I; Jin, Shunqian; Wang, Dong; Muili, Kamaldeen A; Shah, Ahsan U; Eisses, John F; Malik, Adeel; Bottino, Rita; Jayaraman, Thottala; Husain, Sohail Z

    2014-09-01

    Physiological calcium (Ca(2+)) signals within the pancreatic acinar cell regulate enzyme secretion, whereas aberrant Ca(2+) signals are associated with acinar cell injury. We have previously identified the ryanodine receptor (RyR), a Ca(2+) release channel on the endoplasmic reticulum, as a modulator of these pathological signals. In the present study, we establish that the RyR is expressed in human acinar cells and mediates acinar cell injury. We obtained pancreatic tissue from cadaveric donors and identified isoforms of RyR1 and RyR2 by qPCR. Immunofluorescence staining of the pancreas showed that the RyR is localized to the basal region of the acinar cell. Furthermore, the presence of RyR was confirmed from isolated human acinar cells by tritiated ryanodine binding. To determine whether the RyR is functionally active, mouse or human acinar cells were loaded with the high-affinity Ca(2+) dye (Fluo-4 AM) and stimulated with taurolithocholic acid 3-sulfate (TLCS) (500 μM) or carbachol (1 mM). Ryanodine (100 μM) pretreatment reduced the magnitude of the Ca(2+) signal and the area under the curve. To determine the effect of RyR blockade on injury, human acinar cells were stimulated with pathological stimuli, the bile acid TLCS (500 μM) or the muscarinic agonist carbachol (1 mM) in the presence or absence of the RyR inhibitor ryanodine. Ryanodine (100 μM) caused an 81% and 47% reduction in acinar cell injury, respectively, as measured by lactate dehydrogenase leakage (P < 0.05). Taken together, these data establish that the RyR is expressed in human acinar cells and that it modulates acinar Ca(2+) signals and cell injury.

  19. Reciprocal androgen receptor/interleukin-6 crosstalk drives oesophageal carcinoma progression and contributes to patient prognosis.

    PubMed

    Dong, Hongmei; Xu, Jinjin; Li, Weiwei; Gan, Jinfeng; Lin, Wan; Ke, Jierong; Jiang, Jiali; Du, Liang; Chen, Yuping; Zhong, Xueyun; Zhang, Dianzheng; Yeung, Sai-Ching Jim; Li, Xiaotao; Zhang, Hao

    2017-03-01

    Oesophageal squamous cell carcinoma (ESCC), a leading lethal malignancy of the digestive tract, is characterized by marked gender disparity. Clarifying the roles of the function and regulatory pathway of the androgen receptor (AR) will improve our understanding of oesophageal cancer progression, thereby facilitating the personalized management of ESCC. Here we report evidence to show that AR is a key mediator of inflammatory signals in ESCC cancer progression. High AR expression was associated with poor overall survival in tobacco-using ESCC patients but not in ESCC patients not using tobacco. A gain and loss of AR function enhanced and repressed ESCC cell growth, respectively, by altering cell cycle progression. In mice bearing human ESCC xenografts, silencing AR expression attenuated tumour growth, whereas AR overexpression promoted tumour growth in mice of different androgen statuses (male, female, and castrated male). Array assays revealed that the inflammatory cytokine interleukin-6 (IL6) is a prominent AR target gene in ESCC. By directly binding to the IL6 promoter, AR enhances IL6 transcription, and IL6 can in turn activate AR expression, thus forming a reciprocal regulatory circuit to sustain STAT3 oncogenic signalling in ESCC. Moreover, high expression levels of both AR and IL6 in human ESCC predict poor clinical outcome in tobacco users. Together, these data establish that AR promotes ESCC growth and is associated with poor patient prognosis. The discovery of a positive feedback loop between IL6 and AR bridges the knowledge gaps among lifestyle factor-associated inflammation, gender disparity, and oesophageal carcinoma. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  20. Exercise intensity-dependent contribution of beta-adrenergic receptor-mediated vasodilatation in hypoxic humans.

    PubMed

    Wilkins, Brad W; Pike, Tasha L; Martin, Elizabeth A; Curry, Timothy B; Ceridon, Maile L; Joyner, Michael J

    2008-02-15

    We previously reported that hypoxia-mediated reductions in alpha-adrenoceptor sensitivity do not explain the augmented vasodilatation during hypoxic exercise, suggesting an enhanced vasodilator signal. We hypothesized that beta-adrenoceptor activation contributes to augmented hypoxic exercise vasodilatation. Fourteen subjects (age: 29 +/- 2 years) breathed hypoxic gas to titrate arterial O(2) saturation (pulse oximetry) to 80%, while remaining normocapnic via a rebreath system. Brachial artery and antecubital vein catheters were placed in the exercising arm. Under normoxic and hypoxic conditions, baseline and incremental forearm exercise (10% and 20% of maximum) was performed during control (saline), alpha-adrenoceptor inhibition (phentolamine), and combined alpha- and beta-adrenoceptor inhibition (phentolomine/propranolol). Forearm blood flow (FBF), heart rate, blood pressure, minute ventilation, and end-tidal CO(2) were determined. Hypoxia increased heart rate (P < 0.05) and minute ventilation (P < 0.05) at rest and exercise under all drug infusions, whereas mean arterial pressure was unchanged. Arterial adrenaline (P < 0.05) and venous noradrenaline (P < 0.05) were higher with hypoxia during all drug infusions. The change (Delta) in FBF during 10% hypoxic exercise was greater with phentolamine (Delta306 +/- 43 ml min(-1)) vs. saline (Delta169 +/- 30 ml min(-1)) or combined phentolamine/propranolol (Delta213 +/- 25 ml min(-1); P < 0.05 for both). During 20% hypoxic exercise, DeltaFBF was greater with phentalomine (Delta466 +/- 57 ml min(-1); P < 0.05) vs. saline (Delta346 +/- 40 ml min(-1)) but was similar to combined phentolamine/propranolol (Delta450 +/- 43 ml min(-1)). Thus, in the absence of overlying vasoconstriction, the contribution of beta-adrenergic mechanisms to the augmented hypoxic vasodilatation is dependent on exercise intensity.

  1. The Natural Cytotoxicity Receptor 1 Contribution to Early Clearance of Streptococcus pneumoniae and to Natural Killer-Macrophage Cross Talk

    PubMed Central

    Yossef, Rami; Hadad, Uzi; Elkabets, Moshe; Vallon-Eberhard, Alexandra; Hulihel, Luai; Jung, Steffen; Ghadially, Hormas; Braiman, Alex; Apte, Ron N.; Mandelboim, Ofer; Dagan, Ron; Mizrachi-Nebenzahl, Yaffa; Porgador, Angel

    2011-01-01

    Natural killer (NK) cells serve as a crucial first line of defense against tumors, viral and bacterial infections. We studied the involvement of a principal activating natural killer cell receptor, natural cytotoxicity receptor 1 (NCR1), in the innate immune response to S. pneumoniae infection. Our results demonstrate that the presence of the NCR1 receptor is imperative for the early clearance of S. pneumoniae. We tied the ends in vivo by showing that deficiency in NCR1 resulted in reduced lung NK cell activation and lung IFNγ production at the early stages of S. pneumoniae infection. NCR1 did not mediate direct recognition of S. pneumoniae. Therefore, we studied the involvement of lung macrophages and dendritic cells (DC) as the mediators of NK-expressed NCR1 involvement in response to S. pneumoniae. In vitro, wild type BM-derived macrophages and DC expressed ligands to NCR1 and co-incubation of S. pneumoniae-infected macrophages/DC with NCR1-deficient NK cells resulted in significantly lesser IFNγ levels compared to NCR1-expressing NK cells. In vivo, ablation of lung macrophages and DC was detrimental to the early clearance of S. pneumoniae. NCR1-expressing mice had more potent alveolar macrophages as compared to NCR1-deficient mice. This result correlated with the higher fraction of NCR1-ligandhigh lung macrophages, in NCR1-expressing mice, that had better phagocytic activity compared to NCR1-liganddull macrophages. Overall, our results point to the essential contribution of NK-expressed NCR1 in early response to S. pneumoniae infection and to NCR1-mediated interaction of NK and S. pneumoniae infected-macrophages and -DC. PMID:21887255

  2. Receptor subtypes and signal transduction mechanisms contributing to the estrogenic attenuation of cannabinoid-induced changes in energy homeostasis

    PubMed Central

    Washburn, Neal; Borgquist, Amanda; Wang, Kate; Jeffery, Garrett S.; Kelly, Martin J.; Wagner, Edward J.

    2013-01-01

    We examined the receptor subtypes and signal transduction mechanisms contributing to the estrogenic modulation of cannabinoid-induced changes in energy balance. Food intake and, in some cases, O2 consumption, CO2 production and the respiratory exchange ratio, were evaluated in ovariectomized female guinea pigs treated s.c. with the cannabinoid receptor agonist WIN 55,212-2 or its cremephor/ethanol/0.9% saline vehicle, and either with estradiol benzoate (EB), the estrogen receptor (ER)α agonist PPT, the ERβ agonist DPN, the Gq-coupled membrane ER agonist STX, the GPR30 agonist G-1 or their respective vehicles. Patch-clamp recordings were performed in hypothalamic slices. EB, STX, PPT and G-1 decreased daily food intake. Of these, EB, STX and PPT blocked the WIN 55,212-2-induced increase in food intake within 1-4 hr. The estrogenic diminution of cannabinoid-induced hyperphagia correlated with a rapid (within 15 min) attenuation of cannabinoid-mediated decreases in glutamatergic synaptic input onto arcuate neurons, which was completely blocked by inhibition of protein kinase C (PKC) and attenuated by inhibition of protein kinase A (PKA). STX, but not PPT, mimicked this rapid estrogenic effect. However, PPT abolished the cannabinoid-induced inhibition of glutamatergic neurotransmission in cells from animals treated 24 hr prior. The estrogenic antagonism of this presynaptic inhibition was observed in anorexigenic POMC neurons. These data reveal that estrogens negatively modulate cannabinoid-induced changes in energy balance via Gq-coupled membrane ER- and ERα-mediated mechanisms involving activation of PKC and PKA. As such, they further our understanding of the pathways through which estrogens act to temper cannabinoid sensitivity in regulating energy homeostasis in females. PMID:22538462

  3. The natural cytotoxicity receptor 1 contribution to early clearance of Streptococcus pneumoniae and to natural killer-macrophage cross talk.

    PubMed

    Elhaik-Goldman, Shirin; Kafka, Daniel; Yossef, Rami; Hadad, Uzi; Elkabets, Moshe; Vallon-Eberhard, Alexandra; Hulihel, Luai; Jung, Steffen; Ghadially, Hormas; Braiman, Alex; Apte, Ron N; Mandelboim, Ofer; Dagan, Ron; Mizrachi-Nebenzahl, Yaffa; Porgador, Angel

    2011-01-01

    Natural killer (NK) cells serve as a crucial first line of defense against tumors, viral and bacterial infections. We studied the involvement of a principal activating natural killer cell receptor, natural cytotoxicity receptor 1 (NCR1), in the innate immune response to S. pneumoniae infection. Our results demonstrate that the presence of the NCR1 receptor is imperative for the early clearance of S. pneumoniae. We tied the ends in vivo by showing that deficiency in NCR1 resulted in reduced lung NK cell activation and lung IFNγ production at the early stages of S. pneumoniae infection. NCR1 did not mediate direct recognition of S. pneumoniae. Therefore, we studied the involvement of lung macrophages and dendritic cells (DC) as the mediators of NK-expressed NCR1 involvement in response to S. pneumoniae. In vitro, wild type BM-derived macrophages and DC expressed ligands to NCR1 and co-incubation of S. pneumoniae-infected macrophages/DC with NCR1-deficient NK cells resulted in significantly lesser IFNγ levels compared to NCR1-expressing NK cells. In vivo, ablation of lung macrophages and DC was detrimental to the early clearance of S. pneumoniae. NCR1-expressing mice had more potent alveolar macrophages as compared to NCR1-deficient mice. This result correlated with the higher fraction of NCR1-ligand(high) lung macrophages, in NCR1-expressing mice, that had better phagocytic activity compared to NCR1-ligand(dull) macrophages. Overall, our results point to the essential contribution of NK-expressed NCR1 in early response to S. pneumoniae infection and to NCR1-mediated interaction of NK and S. pneumoniae infected-macrophages and -DC.

  4. Identification and elucidation of anthropogenic source contribution in PM10 pollutant: Insight gain from dispersion and receptor models.

    PubMed

    Roy, Debananda; Singh, Gurdeep; Yadav, Pankaj

    2016-10-01

    Source apportionment study of PM10 (Particulate Matter) in a critically polluted area of Jharia coalfield, India has been carried out using Dispersion model, Principle Component Analysis (PCA) and Chemical Mass Balance (CMB) techniques. Dispersion model Atmospheric Dispersion Model (AERMOD) was introduced to simplify the complexity of sources in Jharia coalfield. PCA and CMB analysis indicates that monitoring stations near the mining area were mainly affected by the emission from open coal mining and its associated activities such as coal transportation, loading and unloading of coal. Mine fire emission also contributed a considerable amount of particulate matters in monitoring stations. Locations in the city area were mostly affected by vehicular, Liquid Petroleum Gas (LPG) & Diesel Generator (DG) set emissions, residential, and commercial activities. The experimental data sampling and their analysis could aid understanding how dispersion based model technique along with receptor model based concept can be strategically used for quantitative analysis of Natural and Anthropogenic sources of PM10.

  5. Parsing ERK Activation Reveals Quantitatively Equivalent Contributions From Epidermal Growth Factor Receptor and HER2 In Human Mammary Epithelial Cells

    SciTech Connect

    Hendriks, Bart S.; Orr, Galya; Wells, Alan H.; Wiley, H. S.; Lauffenburger, Douglas A.

    2005-02-18

    HER2, a member of the EGFR tyrosine kinase family, functions as an accessory EGFR signaling component and alters EGFR trafficking by heterodimerization. HER2 overexpression leads to aberrant cell behavior including enhanced proliferation and motility. Here we apply a combination of computational modeling and quantitative experimental studies of the dynamic interactions between EGFR and HER2, and their downstream activation of extracellular signal-related kinase (ERK) to understand this complex signaling system. Using cells expressing different levels of HER2 relative to the EGFR, we can separate relative contributions of EGFR and HER2 to signaling amplitude and duration. Based on our model calculations, we demonstrate that, in contrast with previous suggestions in the literature, the intrinsic capabilities of EGFR and HER2 to activated ERK are quantitatively equivalent . We find that HER2-mediated effects on EGFR dimerization and trafficking are sufficient to explain the detected HER2-mediated amplification of EGF-induced ERK signaling. Our model suggests that transient amplification of ERK activity by HER2 arises predominantly from the 2-to-1 stoichiometry of receptor kinase to bound ligand in EGFR/HER2 heterodimers compared to the 1-to-1 stoichiometry of the EGFR homodimer, but alterations in receptor trafficking, with resultant EGFR sparing, cause the sustained HER2-mediated enhancement of ERK signaling.

  6. The chemokine receptor CXCR6 contributes to recruitment of bone marrow-derived fibroblast precursors in renal fibrosis.

    PubMed

    Xia, Yunfeng; Yan, Jingyin; Jin, Xiaogao; Entman, Mark L; Wang, Yanlin

    2014-08-01

    Bone marrow-derived fibroblasts in circulation are of hematopoietic origin, and they proliferate, differentiate into myofibroblasts, and express the chemokine receptor CXCR6. As chemokines mediate the trafficking of circulating cells to sites of injury, we studied the role of CXCR6 in mouse models of renal injury. Significantly, the kidney of CXCR6 knockout mice accumulated fewer bone marrow-derived fibroblasts in response to injury, expressed less profibrotic chemokines and cytokines, displayed fewer myofibroblasts, and expressed less α-smooth muscle actin in the obstructed kidneys compared with wild-type (WT) mice. CXCR6 deficiency inhibited total collagen deposition and suppressed the expression of collagen I and fibronectin in the obstructed kidneys. Furthermore, WT mice engrafted with CXCR6(-/-) bone marrow cells displayed fewer bone marrow-derived fibroblasts in the kidneys with obstructive injury and showed less severe renal fibrosis compared with WT mice engrafted with CXCR6(+/+) bone marrow cells. Transplant of WT bone marrow into CXCR6(-/-) recipients restored recruitment of myeloid fibroblasts and susceptibility to fibrosis. Hematopoietic fibroblasts migrate into injured kidney and proliferate and differentiate into myofibroblasts. Thus, CXCR6, together with other chemokines and their receptors, may have important roles in the recruitment of bone marrow-derived fibroblast precursors into the kidney and contribute to the pathogenesis of renal fibrosis.

  7. The insulin-like growth factor 1 receptor (IGF1R) contributes to reduced size in dogs.

    PubMed

    Hoopes, Barbara C; Rimbault, Maud; Liebers, David; Ostrander, Elaine A; Sutter, Nathan B

    2012-12-01

    Domestic dog breeds have undergone intense selection for a variety of morphologic features, including size. Among small-dog breeds, defined as those averaging less than ~15 in. at the withers, there remains still considerable variation in body size. Yet essentially all such dogs are fixed for the same allele at the insulin-like growth factor 1 gene, which we and others previously found to be a size locus of large effect. In this study we sought to identify additional genes that contribute to tiny size in dogs using an association scan with the single nucleotide polymorphism (SNP) dataset CanMap, in which 915 purebred dogs were genotyped at 60,968 SNP markers. Our strongest association for tiny size (defined as breed-average height not more than 10 in. at the withers) was on canine chromosome 3 (p = 1.9 × 10(-70)). Fine mapping revealed a nonsynonymous SNP at chr3:44,706,389 that changes a highly conserved arginine at amino acid 204 to histidine in the insulin-like growth factor 1 receptor (IGF1R). This mutation is predicted to prevent formation of several hydrogen bonds within the cysteine-rich domain of the receptor's ligand-binding extracellular subunit. Nine of 13 tiny dog breeds carry the mutation and many dogs are homozygous for it. This work underscores the central importance of the IGF1 pathway in controlling the tremendous size diversity of dogs.

  8. Heightened cleavage of Axl receptor tyrosine kinase by ADAM metalloproteases may contribute to disease pathogenesis in SLE

    PubMed Central

    Orme, Jacob J.; Du, Yong; Vanarsa, Kamala; Mayeux, Jessica; Li, Li; Mutwally, Azza; Arriens, Cristina; Min, Soyoun; Hutcheson, Jack; Davis, Laurie S.; Chong, Benjamin F.; Satterthwaite, Anne B.; Wu, Tianfu; Mohan, Chandra

    2016-01-01

    Systemic lupus erythematosus (SLE) is characterized by antibody-mediated chronic inflammation in the kidney, lung, skin, and other organs to cause inflammation and damage. Several inflammatory pathways are dysregulated in SLE, and understanding these pathways may improve diagnosis and treatment. In one such pathway, Axl tyrosine kinase receptor responds to Gas6 ligand to block inflammation in leukocytes. A soluble form of the Axl receptor ectodomain (sAxl) is elevated in serum from patients with SLE and lupus-prone mice. We hypothesized that sAxl in SLE serum originates from the surface of leukocytes and that the loss of leukocyte Axl contributes to the disease. We determined that macrophages and B cells are a source of sAxl in SLE and in lupus-prone mice. Shedding of the Axl ectodomain from the leukocytes of lupus-prone mice is mediated by the matrix metalloproteases ADAM10 and TACE (ADAM17). Loss of Axl from lupus-prone macrophages renders them unresponsive to Gas6-induced anti-inflammatory signaling in vitro. This phenotype is rescued by combined ADAM10/TACE inhibition. Mice with Axl-deficient macrophages develop worse disease than controls when challenged with anti-glomerular basement membrane (anti-GBM) sera in an induced model of nephritis. ADAM10 and TACE also mediate human SLE PBMC Axl cleavage. Collectively, these studies indicate that increased metalloprotease-mediated cleavage of leukocyte Axl may contribute to end organ disease in lupus. They further suggest dual ADAM10/TACE inhibition as a potential therapeutic modality in SLE. PMID:27237127

  9. Inverse agonism at the P2Y12 receptor and ENT1 transporter blockade contribute to platelet inhibition by ticagrelor

    PubMed Central

    Aungraheeta, Riyaad; Conibear, Alexandra; Butler, Mark; Kelly, Eamonn; Nylander, Sven; Mumford, Andrew

    2016-01-01

    Ticagrelor is a potent antagonist of the P2Y12 receptor (P2Y12R) and consequently an inhibitor of platelet activity effective in the treatment of atherothrombosis. Here, we sought to further characterize its molecular mechanism of action. Initial studies showed that ticagrelor promoted a greater inhibition of adenosine 5′-diphosphate (ADP)–induced Ca2+ release in washed platelets vs other P2Y12R antagonists. This additional effect of ticagrelor beyond P2Y12R antagonism was in part as a consequence of ticagrelor inhibiting the equilibrative nucleoside transporter 1 (ENT1) on platelets, leading to accumulation of extracellular adenosine and activation of Gs-coupled adenosine A2A receptors. This contributed to an increase in basal cyclic adenosine monophosphate (cAMP) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P). In addition, ticagrelor increased platelet cAMP and VASP-P in the absence of ADP in an adenosine receptor–independent manner. We hypothesized that this increase originated from a direct effect on basal agonist-independent P2Y12R signaling, and this was validated in 1321N1 cells stably transfected with human P2Y12R. In these cells, ticagrelor blocked the constitutive agonist-independent activity of the P2Y12R, limiting basal Gi-coupled signaling and thereby increasing cAMP levels. These data suggest that ticagrelor has the pharmacological profile of an inverse agonist. Based on our results showing insurmountable inhibition of ADP-induced Ca2+ release and forskolin-induced cAMP, the mode of antagonism of ticagrelor also appears noncompetitive, at least functionally. In summary, our studies describe 2 novel modes of action of ticagrelor, inhibition of platelet ENT1 and inverse agonism at the P2Y12R that contribute to its effective inhibition of platelet activation. PMID:27694321

  10. New contributions to the study of common double mutants in the human LDL receptor gene

    NASA Astrophysics Data System (ADS)

    Tejedor, M. Teresa; Cenarro, Ana; Tejedor, Diego; Stef, Marianne; Palacios, Lourdes; de Castro, Isabel; García-Otín, Ángel L.; Monteagudo, Luis V.; Civeira, Fernando; Pocovi, Miguel

    2011-11-01

    Variations in the gene encoding the low-density lipoprotein receptor ( LDLR) can cause familial hypercholesterolemia (FH), one of the most common inherited metabolic disorders in humans. The functional effects of the p.Gln92Glu and p.Asn564His alterations are predicted as benign, but the c.313 + 1G>C and p.Lys799_Phe801del changes are believed to cause disease. Although p.Gln92Glu and c.313 + 1G>C have been observed only in Spain, p.Asn564His and p.Lys799_Phe801del are widespread in Western Europe. In order to estimate the ages ( t generations) of these four variants of the gene, to determine their possible origin and to consider the influence of age and selective pressure on their spread, we analyzed 86 healthy individuals and 126 FH patients in Spain. Most of the FH patients investigated carried two of these four LDLR variants simultaneously, while only one patient carried three of them simultaneously. Haplotype analyses were based on five LDLR SNPs: c.81T>C, c.1413G>A, c.1725C>T, c.1959T>C and c.2232G>A. The results suggest that p.Gln92Glu and c.313 + 1G>C arose at about the same time (99 and 103 generations ago, respectively) in the CACTG haplotype and that p.Asn564His and p.Lys799_Phe801del appeared in the CGCCG haplotype and might be slightly more recent variations (92 and 95 generations ago, respectively). Low selective pressures could explain the maintenance of these variants in spite of their ages. The origin of p.Gln92Glu and c.313 + 1G>C appears to be in Spain whereas p.Asn564His and p.Lys799_Phe801del could have been introduced in Spain by Celtic migrations in the seventh to fifth centuries BC.

  11. β-Cell Glucagon-Like Peptide-1 Receptor Contributes to Improved Glucose Tolerance After Vertical Sleeve Gastrectomy.

    PubMed

    Garibay, Darline; McGavigan, Anne K; Lee, Seon A; Ficorilli, James V; Cox, Amy L; Michael, M Dodson; Sloop, Kyle W; Cummings, Bethany P

    2016-09-01

    Vertical sleeve gastrectomy (VSG) produces high rates of type 2 diabetes remission; however, the mechanisms responsible for this remain incompletely defined. Glucagon-like peptide-1 (GLP-1) is a gut hormone that contributes to the maintenance of glucose homeostasis and is elevated after VSG. VSG-induced increases in postprandial GLP-1 secretion have been proposed to contribute to the glucoregulatory benefits of VSG; however, previous work has been equivocal. In order to test the contribution of enhanced β-cell GLP-1 receptor (GLP-1R) signaling we used a β-cell-specific tamoxifen-inducible GLP-1R knockout mouse model. Male β-cell-specific Glp-1r(β-cell+/+) wild type (WT) and Glp-1r(β-cell-/-) knockout (KO) littermates were placed on a high-fat diet for 6 weeks and then switched to high-fat diet supplemented with tamoxifen for the rest of the study. Mice underwent sham or VSG surgery after 2 weeks of tamoxifen diet and were fed ad libitum postoperatively. Mice underwent oral glucose tolerance testing at 3 weeks and were euthanized at 6 weeks after surgery. VSG reduced body weight and food intake independent of genotype. However, glucose tolerance was only improved in VSG WT compared with sham WT, whereas VSG KO had impaired glucose tolerance relative to VSG WT. Augmentation of glucose-stimulated insulin secretion during the oral glucose tolerance test was blunted in VSG KO compared with VSG WT. Therefore, our data suggest that enhanced β-cell GLP-1R signaling contributes to improved glucose regulation after VSG by promoting increased glucose-stimulated insulin secretion.

  12. Targeted Elimination of G Proteins and Arrestins Defines Their Specific Contributions to Both Intensity and Duration of G Protein-coupled Receptor Signaling.

    PubMed

    Alvarez-Curto, Elisa; Inoue, Asuka; Jenkins, Laura; Raihan, Sheikh Zahir; Prihandoko, Rudi; Tobin, Andrew B; Milligan, Graeme

    2016-12-30

    G protein-coupled receptors (GPCRs) can initiate intracellular signaling cascades by coupling to an array of heterotrimeric G proteins and arrestin adaptor proteins. Understanding the contribution of each of these coupling options to GPCR signaling has been hampered by a paucity of tools to selectively perturb receptor function. Here we employ CRISPR/Cas9 genome editing to eliminate selected G proteins (Gαq and Gα11) or arrestin2 and arrestin3 from HEK293 cells together with the elimination of receptor phosphorylation sites to define the relative contribution of G proteins, arrestins, and receptor phosphorylation to the signaling outcomes of the free fatty acid receptor 4 (FFA4). A lack of FFA4-mediated elevation of intracellular Ca(2+) in Gαq/Gα11-null cells and agonist-mediated receptor internalization in arrestin2/3-null cells confirmed previously reported canonical signaling features of this receptor, thereby validating the genome-edited HEK293 cells. FFA4-mediated ERK1/2 activation was totally dependent on Gq/11 but intriguingly was substantially enhanced for FFA4 receptors lacking sites of regulated phosphorylation. This was not due to a simple lack of desensitization of Gq/11 signaling because the Gq/11-dependent calcium response was desensitized by both receptor phosphorylation and arrestin-dependent mechanisms, whereas a substantially enhanced ERK1/2 response was only observed for receptors lacking phosphorylation sites and not in arrestin2/3-null cells. In conclusion, we validate CRISPR/Cas9 engineered HEK293 cells lacking Gq/11 or arrestin2/3 as systems for GPCR signaling research and employ these cells to reveal a previously unappreciated interplay of signaling pathways where receptor phosphorylation can impact on ERK1/2 signaling through a mechanism that is likely independent of arrestins.

  13. Targeted Elimination of G Proteins and Arrestins Defines Their Specific Contributions to Both Intensity and Duration of G Protein-coupled Receptor Signaling*

    PubMed Central

    Alvarez-Curto, Elisa; Inoue, Asuka; Jenkins, Laura; Raihan, Sheikh Zahir; Prihandoko, Rudi; Tobin, Andrew B.

    2016-01-01

    G protein-coupled receptors (GPCRs) can initiate intracellular signaling cascades by coupling to an array of heterotrimeric G proteins and arrestin adaptor proteins. Understanding the contribution of each of these coupling options to GPCR signaling has been hampered by a paucity of tools to selectively perturb receptor function. Here we employ CRISPR/Cas9 genome editing to eliminate selected G proteins (Gαq and Gα11) or arrestin2 and arrestin3 from HEK293 cells together with the elimination of receptor phosphorylation sites to define the relative contribution of G proteins, arrestins, and receptor phosphorylation to the signaling outcomes of the free fatty acid receptor 4 (FFA4). A lack of FFA4-mediated elevation of intracellular Ca2+ in Gαq/Gα11-null cells and agonist-mediated receptor internalization in arrestin2/3-null cells confirmed previously reported canonical signaling features of this receptor, thereby validating the genome-edited HEK293 cells. FFA4-mediated ERK1/2 activation was totally dependent on Gq/11 but intriguingly was substantially enhanced for FFA4 receptors lacking sites of regulated phosphorylation. This was not due to a simple lack of desensitization of Gq/11 signaling because the Gq/11-dependent calcium response was desensitized by both receptor phosphorylation and arrestin-dependent mechanisms, whereas a substantially enhanced ERK1/2 response was only observed for receptors lacking phosphorylation sites and not in arrestin2/3-null cells. In conclusion, we validate CRISPR/Cas9 engineered HEK293 cells lacking Gq/11 or arrestin2/3 as systems for GPCR signaling research and employ these cells to reveal a previously unappreciated interplay of signaling pathways where receptor phosphorylation can impact on ERK1/2 signaling through a mechanism that is likely independent of arrestins. PMID:27852822

  14. NMDA receptor mediated phosphorylation of GluR1 subunits contributes to the appearance of calcium-permeable AMPA receptors after mechanical stretch injury

    PubMed Central

    Spaethling, Jennifer; Le, Linda; Meaney, David F

    2016-01-01

    Alterations in neuronal cytosolic calcium is a key mediator of the traumatic brain injury (TBI) pathobiology, but less is known of the role and source of calcium in shaping early changes in synaptic receptors and neural circuits after TBI. In this study, we examined the calcium source and potential phosphorylation events leading to insertion of calcium-permeable AMPARs (CP-AMPARs) after in vitro traumatic brain injury, a receptor subtype that influences neural circuit dynamics for hours to days following injury. We found that both synaptic and NR2B-containing NMDARs contribute significantly to the calcium influx following stretch injury. Moreover, an early and sustained phosphorylation of the S-831 site of the GluR1 subunit appeared after mechanical injury, and this phosphorylation was blocked with the inhibition of either synaptic NMDARs or NR2B-containing NMDARs. In comparison, mechanical injury led to no significant change in the S-845 phosphorylation of the GluR1 subunit. Although no change in S-845 phosphorylation appeared in injured cultures, we observed that inhibition of NR2B-containing NMDARs significantly increased S-845 phosphorylation one hour after injury while blockade of synaptic NMDARs did not change S-845 phosphorylation at any time point following injury. These findings show that a broad class of NMDARs are activated in parallel and that targeting either subpopulation will reverse some of the consequences of mechanical injury, providing distinct paths to treat the effects of mechanical injury on neural circuits after TBI. PMID:22426393

  15. Bioassays for TSH Receptor Autoantibodies, from FRTL-5 Cells to TSH Receptor–LH/CG Receptor Chimeras: The Contribution of Leonard D. Kohn

    PubMed Central

    Giuliani, Cesidio; Saji, Motoyasu; Bucci, Ines; Napolitano, Giorgio

    2016-01-01

    Since the discovery 60 years ago of the “long-acting thyroid stimulator” by Adams and Purves, great progress has been made in the detection of thyroid-stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAbs) in Graves’ disease. Today, commercial assays are available that can detect TRAbs with high accuracy and provide diagnostic and prognostic evaluation of patients with Graves’ disease. The present review focuses on the development of TRAbs bioassays, and particularly on the role that Leonard D. Kohn had in this. Indeed, 30 years ago, the Kohn group developed a bioassay based on the use of FRTL-5 cells that was characterized by high reproducibility, feasibility, and diagnostic accuracy. Using this FRTL-5 bioassay, Kohn and his colleagues were the first to develop monoclonal antibodies (moAbs) against the TSHR. Furthermore, they demonstrated the multifaceted functional nature of TRAbs in patients with Graves’ disease, with the identification of stimulating and blocking TRAbs, and even antibodies that activated pathways other than cAMP. After the cloning of the TSHR, the Kohn laboratory constructed human TSHR–rat luteinizing hormone/chorionic gonadotropin receptor chimeras. This paved the way to a new bioassay based on the use of non-thyroid cells transfected with the Mc4 chimera. The new Mc4 bioassay is characterized by high diagnostic and prognostic accuracy, greater than for other assays. The availability of a commercial kit based on the Mc4 chimera is spreading the use of this assay worldwide, indicating its benefits for these patients with Graves’ disease. This review also describes the main contributions made by other researchers in TSHR molecular biology and TRAbs assay, especially with the development of highly potent moAbs. A comparison of the diagnostic accuracies of the main TRAbs assays, as both immunoassays and bioassays, is also provided. PMID:27504107

  16. Loss of the EPH receptor B6 contributes to colorectal cancer metastasis

    PubMed Central

    Mateo-Lozano, Silvia; Bazzocco, Sarah; Rodrigues, Paulo; Mazzolini, Rocco; Andretta, Elena; Dopeso, Higinio; Fernández, Yolanda; del Llano, Edgar; Bilic, Josipa; Suárez-López, Lucía; Macaya, Irati; Cartón-García, Fernando; Nieto, Rocio; Jimenez-Flores, Lizbeth M.; de Marcondes, Priscila Guimarães; Nuñez, Yaiza; Afonso, Elsa; Cacci, Karina; Hernández-Losa, Javier; Landolfi, Stefania; Abasolo, Ibane; Ramón y Cajal, Santiago; Mariadason, John M.; Schwartz, Simo; Matsui, Toshimitsu; Arango, Diego

    2017-01-01

    Although deregulation of EPHB signaling has been shown to be an important step in colorectal tumorigenesis, the role of EPHB6 in this process has not been investigated. We found here that manipulation of EPHB6 levels in colon cancer cell lines has no effect on their motility and growth on a solid substrate, soft agar or in a xenograft mouse model. We then used an EphB6 knockout mouse model to show that EphB6 inactivation does not efficiently initiate tumorigenesis in the intestinal tract. In addition, when intestinal tumors are initiated genetically or pharmacologically in EphB6+/+ and EphB6−/− mice, no differences were observed in animal survival, tumor multiplicity, size or histology, and proliferation of intestinal epithelial cells or tumor cells. However, reintroduction of EPHB6 into colon cancer cells significantly reduced the number of lung metastasis after tail-vein injection in immunodeficient mice, while EPHB6 knockdown in EPHB6-expressing cells increased their metastatic spread. Consistently, although EPHB6 protein expression in a series of 130 primary colorectal tumors was not associated with patient survival, EPHB6 expression was significantly lower in lymph node metastases compared to primary tumors. Our results indicate that the loss of EPHB6 contributes to the metastatic process of colorectal cancer. PMID:28262839

  17. Loss of the EPH receptor B6 contributes to colorectal cancer metastasis.

    PubMed

    Mateo-Lozano, Silvia; Bazzocco, Sarah; Rodrigues, Paulo; Mazzolini, Rocco; Andretta, Elena; Dopeso, Higinio; Fernández, Yolanda; Del Llano, Edgar; Bilic, Josipa; Suárez-López, Lucía; Macaya, Irati; Cartón-García, Fernando; Nieto, Rocio; Jimenez-Flores, Lizbeth M; de Marcondes, Priscila Guimarães; Nuñez, Yaiza; Afonso, Elsa; Cacci, Karina; Hernández-Losa, Javier; Landolfi, Stefania; Abasolo, Ibane; Ramón Y Cajal, Santiago; Mariadason, John M; Schwartz, Simo; Matsui, Toshimitsu; Arango, Diego

    2017-03-06

    Although deregulation of EPHB signaling has been shown to be an important step in colorectal tumorigenesis, the role of EPHB6 in this process has not been investigated. We found here that manipulation of EPHB6 levels in colon cancer cell lines has no effect on their motility and growth on a solid substrate, soft agar or in a xenograft mouse model. We then used an EphB6 knockout mouse model to show that EphB6 inactivation does not efficiently initiate tumorigenesis in the intestinal tract. In addition, when intestinal tumors are initiated genetically or pharmacologically in EphB6(+/+) and EphB6(-/-) mice, no differences were observed in animal survival, tumor multiplicity, size or histology, and proliferation of intestinal epithelial cells or tumor cells. However, reintroduction of EPHB6 into colon cancer cells significantly reduced the number of lung metastasis after tail-vein injection in immunodeficient mice, while EPHB6 knockdown in EPHB6-expressing cells increased their metastatic spread. Consistently, although EPHB6 protein expression in a series of 130 primary colorectal tumors was not associated with patient survival, EPHB6 expression was significantly lower in lymph node metastases compared to primary tumors. Our results indicate that the loss of EPHB6 contributes to the metastatic process of colorectal cancer.

  18. Contribution of NMDA and non-NMDA receptors to in vivo glutamate-induced calpain activation in the rat striatum. Relation to neuronal damage.

    PubMed

    Del Río, Perla; Montiel, Teresa; Massieu, Lourdes

    2008-08-01

    Glutamate, the major excitatory neurotransmitter, can cause the death of neurons by a mechanism known as excitotoxicity. This is a calcium-dependent process and activation of the NMDA receptor subtype contributes mainly to neuronal damage, due to its high permeability to calcium. Activation of calpain, a calcium-dependent cysteine protease, has been implicated in necrotic excitotoxic neuronal death. We have investigated the contribution of NMDA and non-NMDA ionotropic receptors to calpain activation and neuronal death induced by the acute administration of glutamate into the rat striatum. Calpain activity was assessed by the cleavage of the cytoskeletal protein, alpha-spectrin. Caspase-3 activity was also studied because glutamate can also lead to apoptosis. Results show no caspase-3 activity, but a strong calpain activation involving both NMDA and non-NMDA receptors. Although neuronal damage is mediated mainly by the NMDA receptor subtype, it can not be attributed solely to calpain activity.

  19. Receptor modeling of source apportionment of Hong Kong aerosols and the implication of urban and regional contribution

    NASA Astrophysics Data System (ADS)

    Guo, H.; Ding, A. J.; So, K. L.; Ayoko, G.; Li, Y. S.; Hung, W. T.

    Understanding the spatial-temporal variations of source apportionment of PM 2.5 is critical to the effective control of particulate pollution. In this study, two one-year studies of PM 2.5 composition were conducted at three contrasting sites in Hong Kong from November 2000 to October 2001, and from November 2004 to October 2005, respectively. A receptor model, principal component analysis (PCA) with absolute principal component scores (APCS) technique, was applied to the PM 2.5 data for the identification and quantification of pollution sources at the rural, urban and roadside sites. The receptor modeling results identified that the major sources of PM 2.5 in Hong Kong were vehicular emissions/road erosion, secondary sulfate, residual oil combustion, soil suspension and sea salt regardless of sampling sites and sampling periods. The secondary sulfate aerosols made the most significant contribution to the PM 2.5 composition at the rural (HT) (44 ± 3%, mean ± 1 σ standard error) and urban (TW) (28 ± 2%) sites, followed by vehicular emission (20 ± 3% for HT and 23 ± 4% for TW) and residual oil combustion (17 ± 2% for HT and 19 ± 1% for TW). However, at the roadside site (MK), vehicular emissions especially diesel vehicle emissions were the major source of PM 2.5 composition (33 ± 1% for diesel vehicle plus 18 ± 2% for other vehicles), followed by secondary sulfate aerosols (24 ± 1%). We found that the contribution of residual oil combustion at both urban and rural sites was much higher than that at the roadside site (2 ± 0.4%), perhaps due to the marine vessel activities of the container terminal near the urban site and close distance of pathway for the marine vessels to the rural site. The large contribution of secondary sulfate aerosols at all the three sites reflected the wide influence of regional pollution. With regard to the temporal trend, the contributions of vehicular emission and secondary sulfate to PM 2.5 showed higher autumn and winter values

  20. Associations between oxytocin receptor genotypes and social cognitive performance in individuals with schizophrenia.

    PubMed

    Davis, Michael C; Horan, William P; Nurmi, Erika L; Rizzo, Shemra; Li, Wendy; Sugar, Catherine A; Green, Michael F

    2014-11-01

    Individuals with schizophrenia often show substantial deficits in social cognitive abilities, which are strongly associated with social functioning. To advance our understanding of the genetic variation that is associated with social cognitive deficits in schizophrenia, we genotyped 74 schizophrenia outpatients who completed social cognitive performance measures assessing mentalizing, social perception, and emotional intelligence, as well as clinical symptoms. We assessed seven single nucleotide polymorphisms (SNPs) of the oxytocin receptor (OXTR) previously found to show replicable associations with socio-emotional processes. For one of the seven SNPs, rs2268493, the 'T' allele was significantly associated with poorer performance on a composite social cognition index, as well as specific tests of mentalizing and social perception. None of the SNPs were associated with clinical symptoms. Though the sample size is small, these findings provide initial support for the involvement of genetic variants of the OXTR in social cognitive impairments in schizophrenia.

  1. Peroxisome proliferator activated receptor-γ-Rho-kinase interactions contribute to vascular remodeling after chronic intrauterine pulmonary hypertension

    PubMed Central

    Tseng, Nancy; Seedorf, Gregory; Roe, Gates; Abman, Steven H.

    2013-01-01

    Peroxisome proliferator-activated receptor-γ (PPARγ) and Rho-kinase (ROCK) regulate smooth muscle cell (SMC) proliferation and contribute to vascular remodeling in adult pulmonary hypertension. Whether these pathways interact to contribute to the development of vascular remodeling in persistent pulmonary hypertension of the newborn (PPHN) remains unknown. We hypothesized that ROCK-PPARγ interactions increase SMC proliferation resulting in vascular remodeling in experimental PPHN. Pulmonary artery SMCs (PASMCs) were harvested from fetal sheep after partial ligation of the ductus arteriosus in utero (PPHN) and controls. Cell counts were performed daily for 5 days with or without PPARγ agonists and ROCK inhibition. PPARγ and ROCK protein expression/activity were measured by Western blot in normal and PPHN PASMCs. We assessed PPARγ-ROCK interactions by studying the effect of ROCK activation on PPARγ activity and PPARγ inhibition (siRNA) on ROCK activity and PASMC proliferation. At baseline, PPHN PASMC cell number was increased by 38% above controls on day 5. ROCK protein expression/activity were increased by 25 and 34% and PPARγ protein/activity decreased by 40 and 50% in PPHN PASMC. ROCK inhibition and PPARγ activation restored PPHN PASMC growth to normal values. ROCK inhibition increased PPARγ activity by 50% in PPHN PASMC, restoring PPARγ activity to normal. In normal PASMCs, ROCK activation decreased PPARγ activity and PPARγ inhibition increased ROCK activity and cell proliferation, resulting in a PPHN hyperproliferative PASMC phenotype. PPARγ-ROCK interactions regulate SMC proliferation and contribute to increased PPHN PASMC proliferation and vascular remodeling in PPHN. Restoring normal PPARγ-ROCK signaling may prevent vascular remodeling and improve outcomes in PPHN. PMID:24375792

  2. Oxytocin and arginine vasopressin receptor evolution: implications for adaptive novelties in placental mammals

    PubMed Central

    Paré, Pamela; Paixão-Côrtes, Vanessa R.; Tovo-Rodrigues, Luciana; Vargas-Pinilla, Pedro; Viscardi, Lucas Henriques; Salzano, Francisco Mauro; Henkes, Luiz E.; Bortolini, Maria Catira

    2016-01-01

    Abstract Oxytocin receptor (OXTR) and arginine vasopressin receptors (AVPR1a, AVPR1b, and AVPR2) are paralogous genes that emerged through duplication events; along the evolutionary timeline, owing to speciation, numerous orthologues emerged as well. In order to elucidate the evolutionary forces that shaped these four genes in placental mammals and to reveal specific aspects of their protein structures, 35 species were selected. Specifically, we investigated their molecular evolutionary history and intrinsic protein disorder content, and identified the presence of short linear interaction motifs. OXTR seems to be under evolutionary constraint in placental mammals, whereas AVPR1a, AVPR1b, and AVPR2 exhibit higher evolutionary rates, suggesting that they have been under relaxed or experienced positive selection. In addition, we describe here, for the first time, that the OXTR, AVPR1a, AVPR1b, and AVPR2 mammalian orthologues preserve their disorder content, while this condition varies among the paralogues. Finally, our results reveal the presence of short linear interaction motifs, indicating possible functional adaptations related to physiological and/or behavioral taxa-specific traits. PMID:27505307

  3. Contribution of NMDA receptor-mediated component to the EPSP in mouse Schaffer collateral synapses under single pulse stimulation protocol.

    PubMed

    Neagu, Bogdan; Strominger, Norman L; Carpenter, David O

    2008-11-13

    The degree to which NMDA receptors contribute to hippocampal CA(1) stratum radiatum excitatory postsynaptic potentials (EPSP) is a matter of debate. This experiment was designed to resolve the issue by documenting and positively identifying the elements of the NMDA dependent component in the extracellularly recorded stratum radiatum CA(1) field potential under low stimulation conditions and in the presence of physiologic levels of Mg(2+). We show that EPSP generation consists of activation of both AMPA and NMDA receptor channels, which mediate distinct components of the recorded field potential. We propose that the EPSP is a combination of two waves rather than one, which sometimes has been attributed to the exclusive activation of AMPA channels. Our data suggest that the three recorded peaks signify different events. The first peak reflects the presynaptic volley while the other two represent the actual EPSP. The first peak of the EPSP is determined mainly by flow of ions through AMPA channels. The second peak most likely is determined by the concurrence of two phenomena: ionic flow through NMDA channels and the source corresponding to the sink generated at the cell bodies in the pyramidal layer. The NMDA dependent component was recorded when Mg(2+) was present in physiological concentrations. The presynaptic volley and second peak do not saturate over a 10-fold increase of the stimulation charge and their amplitudes are highly correlated. The first peak amplitude rapidly saturates. The sensitivity of the recorded signals is different, the first peak being the most sensitive (1.25-0.26 mV/nC). Isolation of NMDA dependent components under physiological conditions when using a single pulse low stimulation protocol would allow more precise investigations of the NMDA dependent forms of synaptic plasticity.

  4. Diverse activation states of RhoA in human lung cancer cells: contribution of G protein coupled receptors.

    PubMed

    Touge, Hirokazu; Chikumi, Hiroki; Igishi, Tadashi; Kurai, Jun; Makino, Haruhiko; Tamura, Yoshisato; Takata, Miyako; Yoneda, Kazuhiko; Nakamoto, Masaki; Suyama, Hisashi; Gutkind, J Silvio; Shimizu, Eiji

    2007-03-01

    Rho GTPases play an essential role in the control of various cellular functions. Accumulating evidence suggests that RhoA overexpression contributes to human cancer development. However, the activation states of RhoA are poorly defined in cancer cells. In this study, we examined both the expression levels and the activation states of RhoA in various lung cancer cells by quantitative real-time reverse transcriptase-polymerase chain reaction and in vivo Rho guanine nucleotide exchange assay, respectively. Moreover, we dissected the signaling pathway from the cell surface receptors to RhoA using a broad-spectrum G protein coupled receptor (GPCR) antagonist, [D-Arg1,D-Trp5,7,9,Leu11]Substance P (SP), and a recently reported Galphaq/11-selective inhibitor, YM-254890. We found that RhoA was expressed highly in large cell carcinoma cells but only weakly in adenocarcinoma cells. The activation states of RhoA are considerably different from its expression profiles. We found that four of six small cell lung carcinoma (SCLC) cell lines exhibited a moderate to high activation rate of RhoA. The addition of [D-Arg1,D-Trp5,7,9,Leu11]SP reduced RhoA activity by almost 60% in H69 SCLC cells. The addition of YM-254890 had no effect on RhoA activity in H69 cells. Our results suggest that RhoA is activated in various lung cancer cells independent of its expression levels, and the high activation state of RhoA in SCLC cells mainly depends on a neuroendocrine peptide autocrine system which signals through Galpha12 coupled GPCR to RhoA. This study provides new insights into RhoA signaling in lung cancer cells and may help in developing novel therapeutic strategies against lung cancer.

  5. Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality.

    PubMed

    Armeni, Anastasia K; Assimakopoulos, Konstantinos; Marioli, Dimitra; Koika, Vassiliki; Michaelidou, Euthychia; Mourtzi, Niki; Iconomou, Gregoris; Georgopoulos, Neoklis A

    2017-01-01

    Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA) gene polymorphism (rs2234693-PvuII) (T→C substitution) and oxytocin receptor gene polymorphism (rs53576) (G→A substitution) with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20-25 years of age, sexually active, with normal menstrual cycles (28-35 days), were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs), polycystic ovary syndrome (PCOS), thyroid diseases as well as drugs that are implicated in hypothalamus-pituitary-gonadal axis. T allele (wildtype) of rs2234693 (PvuII) polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic) of rs53576 (OXTR) polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII) and A allele of rs53576 (OXTR) polymorphisms (T + A group) was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences.

  6. Impact of estrogen receptor α gene and oxytocin receptor gene polymorphisms on female sexuality

    PubMed Central

    Armeni, Anastasia K; Assimakopoulos, Konstantinos; Marioli, Dimitra; Koika, Vassiliki; Michaelidou, Euthychia; Mourtzi, Niki; Iconomou, Gregoris

    2017-01-01

    Over the past decades, research attention has increasingly been paid to the neurobiological component of sexual behavior. The aim of the present study was to investigate the correlation of estrogen receptor α (ERA) gene polymorphism (rs2234693-PvuII) (T→C substitution) and oxytocin receptor gene polymorphism (rs53576) (G→A substitution) with sexuality parameters of young, healthy women. One hundred thirty-three Greek heterosexual women, students in higher education institutions, 20–25 years of age, sexually active, with normal menstrual cycles (28–35 days), were recruited in the study. Exclusion criteria were chronic and/or major psychiatric diseases, use of oral contraceptive pills (OCs), polycystic ovary syndrome (PCOS), thyroid diseases as well as drugs that are implicated in hypothalamus–pituitary–gonadal axis. T allele (wildtype) of rs2234693 (PvuII) polymorphism of ERA gene was correlated with increased levels of arousal and lubrication, whereas A allele (polymorphic) of rs53576 (OXTR) polymorphism was correlated with increased arousal levels. The simultaneous presence of both T allele of rs2234693 (PvuII) and A allele of rs53576 (OXTR) polymorphisms (T + A group) was correlated with increased arousal, orgasm levels as well as female sexual function index full score. To our knowledge, this is the first study to investigate the interaction between ERA and OXTR with regard to sexual function in women. Female sexuality is a complex behavioral trait that encompasses both biological and psychological components. It seems that variability in female sexual response stems from genetic variability that characterizes endocrine, neurotransmitter and central nervous system influences. PMID:28069897

  7. Association between Genetic Variation in the Oxytocin Receptor Gene and Emotional Withdrawal, but not between Oxytocin Pathway Genes and Diagnosis in Psychotic Disorders

    PubMed Central

    Haram, Marit; Tesli, Martin; Bettella, Francesco; Djurovic, Srdjan; Andreassen, Ole Andreas; Melle, Ingrid

    2015-01-01

    Social dysfunction is common in patients with psychotic disorders. Oxytocin is a neuropeptide with a central role in social behavior. This study aims to explore the relationship between oxytocin pathway genes and symptoms related to social dysfunction in patients with psychotic disorders. We performed association analyses between four oxytocin pathway genes (OXT, OXTR, AVP, and CD38) and four areas of social behavior-related psychopathology as measured by Positive and Negative Syndrome Scale. For this purpose, we used both a polygenic risk score (PGRS) and single OXTR candidate single nucleotide polymorphism previously reported in the literature (rs53576, rs237902, and rs2254298). A total of 734 subjects with DSM-IV psychotic spectrum disorders and 420 healthy controls were included. Oxytocin pathway PGRSs were calculated based on the independent Psychiatric Genomics Consortium study sample. There was a significant association between symptom of Emotional Withdrawal and the previously reported OXTR risk allele A in rs53576. No significant associations between oxytocin pathway gene variants and a diagnosis of psychotic disorder were found. Our findings indicate that while oxytocin pathway genes do not appear to contribute to the susceptibility to psychotic disorders, variations in the OXTR gene might play a role in the development of impaired social behavior. PMID:25667571

  8. The Contribution of Peroxisome Proliferator-Activated Receptor Alpha to the Relationship Between Toxicokinetics and Toxicodynamics of Trichloroethylene.

    PubMed

    Yoo, Hong Sik; Cichocki, Joseph A; Kim, Sungkyoon; Venkatratnam, Abhishek; Iwata, Yasuhiro; Kosyk, Oksana; Bodnar, Wanda; Sweet, Stephen; Knap, Anthony; Wade, Terry; Campbell, Jerry; Clewell, Harvey J; Melnyk, Stepan B; Chiu, Weihsueh A; Rusyn, Ivan

    2015-10-01

    Exposure to the ubiquitous environmental contaminant trichloroethylene (TCE) is associated with cancer and non-cancer toxicity in both humans and rodents. Peroxisome proliferator-activated receptor-alpha (PPARα) is thought to be playing a role in liver toxicity in rodents through activation of the receptor by the TCE metabolite trichloroacetic acid (TCA). However, most studies using genetically altered mice have not assessed the potential for PPARα to alter TCE toxicokinetics, which may lead to differences in TCA internal doses and hence confound inferences as to the role of PPARα in TCE toxicity. To address this gap, male and female wild type (129S1/SvImJ), Pparα-null, and humanized PPARα (hPPARα) mice were exposed intragastrically to 400 mg/kg TCE in single-dose (2, 5 and 12 h) and repeat-dose (5 days/week, 4 weeks) studies. Interestingly, following either a single- or repeat-dose exposure to TCE, levels of TCA in liver and kidney were lower in Pparα-null and hPPARα mice as compared with those in wild type mice. Levels of trichloroethanol (TCOH) were similar in all strains. TCE-exposed male mice consistently had higher levels of TCA and TCOH in all tissues compared with females. Additionally, in both single- and repeat-dose studies, a similar degree of induction of PPARα-responsive genes was observed in liver and kidney of hPPARα and wild type mice, despite the difference in hepatic and renal TCA levels. Additional sex- and strain-dependent effects were observed in the liver, including hepatocyte proliferation and oxidative stress, which were not dependent on TCA or TCOH levels. These data demonstrate that PPARα status affects the levels of the putative PPARα agonist TCA following TCE exposure. Therefore, interpretations of studies using Pparα-null and hPPARα mice need to consider the potential contribution of genotype-dependent toxicokinetics to observed differences in toxicity, rather than attributing such differences only to receptor

  9. Oxytocin receptor signalling.

    PubMed

    Devost, Dominic; Wrzal, Paulina; Zingg, Hans H

    2008-01-01

    The great diversity of the expression sites and proposed function of the oxytocin (OXT) receptor (OXTR) is paralleled by a diversity of its signalling pathways, many of which have still remained unexplored. We have used different approaches to discover novel pathways. By means of a phosphoproteomics approach, we have detected several distinct OXT-induced changes in tyrosine as well as threonine phosphorylation states of intracellular protein in myometrial cells. The most prominent change involved dephosphorylation of a 95-kDa phosphothreonine moiety. By N-terminal amino acid microsequence analysis, this moiety was shown to correspond to eukaryotic translation factor eEF2. This protein is a key regulator of protein synthesis and mediates, upon dephosphorylation, the translocation step of peptide chain elongation. These findings define a novel mechanism by which OXT assumes a so far unrecognized trophic function. We next elucidated the intracellular pathway(s) involved. We found that this effect is not mediated by any of the known pathways known to induce eEF2 dephosphorylation (mTOR, ERK1/2 or p38) but by protein kinase C. Consistent with this idea, we also found that direct stimulation of protein kinase C with a phorbol ester induced eEF2 dephosphorylation in myometrial cells. Using phosphoERK antibodies, we discovered by Western blotting that OXT induced phosphorylation of a higher molecular weight ERK-related protein. We were able to show that this band corresponded to "big MAP kinase1" or ERK5. ERK5 is part of a distinct MAPK cascade and promotes expression of the myosin light chain gene and plays an obligatory role in muscle cell development and differentiation. The role of ERK5 in myometrium has remained unexplored, but it is likely to represent an important novel pathway mediating OXT's effects on smooth muscle function. Further elucidation of these novel signalling pathways will have significant relevance for the development of novel pathway-specific OXTR

  10. Progesterone-induced activation of membrane-bound progesterone receptors in murine macrophage cells.

    PubMed

    Lu, Jing; Reese, Joshua; Zhou, Ying; Hirsch, Emmet

    2015-02-01

    Parturition is an inflammatory process mediated to a significant extent by macrophages. Progesterone (P4) maintains uterine quiescence in pregnancy, and a proposed functional withdrawal of P4 classically regulated by nuclear progesterone receptors (nPRs) leads to labor. P4 can affect the functions of macrophages despite the reported lack of expression of nPRs in these immune cells. Therefore, in this study we investigated the effects of the activation of the putative membrane-associated PR on the function of macrophages (a key cell for parturition) and discuss the implications of these findings for pregnancy and parturition. In murine macrophage cells (RAW 264.7), activation of mPRs by P4 modified to be active only extracellularly by conjugation to BSA (P4BSA, 1.0×10(-7) mol/l) caused a pro-inflammatory shift in the mRNA expression profile, with significant upregulation of the expression of cyclooxygenase 2 (COX2 (Ptgs2)), Il1B, and Tnf and downregulation of membrane progesterone receptor alpha (Paqr7) and oxytocin receptor (Oxtr). Pretreatment with PD98059, a MEK1/2 inhibitor, significantly reduced P4BSA-induced expression of mRNA of Il1B, Tnf, and Ptgs2. Inhibition of protein kinase A (PKA) by H89 blocked P4BSA-induced expression of Il1B and Tnf mRNA. P4BSA induced rapid phosphorylation of MEK1/2 and CREB (a downstream target of PKA). This phosphorylation was inhibited by pretreatment with PD98059 and H89, respectively, revealing that MEK1/2 and PKA are two of the components involved in mPR signaling. Taken together, these results indicate that changes in membrane progesterone receptor alpha expression and signaling in macrophages are associated with the inflammatory responses; and that these changes might contribute to the functional withdrawal of P4 related to labor.

  11. Plasticity in the contribution of T cell receptor variable region residues to binding of peptide-HLA-A2 complexes

    PubMed Central

    Smith, Sheena N.; Sommermeyer, Daniel; Piepenbrink, Kurt H.; Blevins, Sydney J.; Bernhard, Helga; Uckert, Wolfgang; Baker, Brian M.; Kranz, David M.

    2013-01-01

    One hypothesis to account for MHC-restriction by T cell receptors (TCRs) holds that there are several evolutionary-conserved residues in TCR variable regions that contact MHC. While this ‘germline-codon’ hypothesis is supported by various lines of evidence, it has been difficult to test. The difficulty stems in part from the fact that TCRs exhibit low affinities for pep/MHC, thus limiting the range of binding energies that can be assigned to these key interactions using mutational analyses. To measure the magnitude of binding energies involved, here we used high-affinity TCRs engineered by mutagenesis of CDR3. The TCRs included a high-affinity, MART-1/HLA-A2-specific single-chain TCR and two other high-affinity TCRs that all contain the same Vα (HLA-A2), with different peptides and Vβ regions. Mutational analysis of residues in CDR1 and CDR2 of the three Vα2 regions showed the importance of the key ‘germline codon” residue Y51. However, two other proposed key residues showed significant differences among the TCRs in their relative contributions to binding. Using single-position, yeast-display libraries in two of the key residues, MART-1/HLA-A2 selections also revealed strong preferences for wild-type ‘germline codon’ residues, but several alternative residues could also accommodate binding and hence, MHC-restriction. Thus, although a single residue (Y51) could account for a proportion of the energy associated with positive selection (i.e. MHC-restriction), there is significant plasticity in requirements for particular side-chains in CDR1 and CDR2 and in their relative binding contributions among different TCRs. PMID:23954306

  12. Contributions of aryl hydrocarbon receptor genetic variants to the risk of glioma and PAH-DNA adducts.

    PubMed

    Gu, Aihua; Ji, Guixiang; Jiang, Tao; Lu, Ailin; You, Yongping; Liu, Ning; Luo, Chengzhang; Yan, Wei; Zhao, Peng

    2012-08-01

    The aryl hydrocarbon receptor (AHR) gene is involved in the response to polycyclic aromatic hydrocarbon (PAH) exposure. To investigate the hypothesis that the genetic variants in the AHR gene might be a causal genetic susceptibility to PAH-DNA adduct formation and glioma risk, we conducted a case-control study of 384 glioma cases and 384 cancer-free controls to explore the association between six common single-nucleotide polymorphisms of the AHR gene and glioma risk. Using PAH-DNA adducts as biomarkers, we then evaluated the association between PAH-DNA adduct levels and glioma risk based on a tissue microarray including 11 controls and 77 glioma patients. We further explored the contributions of the glioma risk-associated AHR polymorphisms to the levels of PAH-DNA adducts in glioma tissues based on 77 glioma patients. We found that PAH-DNA adduct staining existed in normal brain tissues and grades I-IV gliomas, and the staining intensity was significantly associated with the glioma grade. Two AHR polymorphisms (rs2066853 and rs2158041) demonstrated significant association with glioma risk. Intriguingly, we also found statistically significant associations between these two variants and PAH-DNA adduct levels in glioma tissue. These data suggest the contributions of AHR rs2066853 and rs2158041 to glioma risk and the PAH-DNA adduct levels, which shed new light on gene-environment interactions in the etiology of glioma. Further studies with a larger sample size and ethnically diverse populations are required to elucidate the potential biological mechanism for, as well as the impact of, the susceptibility to glioma due to genetic variants of AHR.

  13. Contribution of the toxic advanced glycation end-products-receptor axis in nonalcoholic steatohepatitis-related hepatocellular carcinoma

    PubMed Central

    Takino, Jun-ichi; Nagamine, Kentaro; Hori, Takamitsu; Sakasai-Sakai, Akiko; Takeuchi, Masayoshi

    2015-01-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. The main etiologies of HCC are hepatitis B virus and hepatitis C virus (HCV), and non-hepatitis B/non-hepatitis C HCC (NBNC-HCC) has also been identified as an etiological factor. Although the incidence of HCV-related HCC in Japan has decreased slightly in recent years, that of NBNC-HCC has increased. The onset mechanism of NBNC-HCC, which has various etiologies, remains unclear; however, nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease, is known to be an important risk factor for NBNC-HCC. Among the different advanced glycation end-products (AGEs) formed by the Maillard reaction, glyceraldehyde-derived AGEs, the predominant components of toxic AGEs (TAGE), have been associated with NASH and NBNC-HCC, including NASH-related HCC. Furthermore, the expression of the receptor for AGEs (RAGE) has been correlated with the malignant progression of HCC. Therefore, TAGE induce oxidative stress by binding with RAGE may, in turn, lead to adverse effects, such as fibrosis and malignant transformation, in hepatic stellate cells and tumor cells during NASH or NASH-related HCC progression. The aim of this review was to examine the contribution of the TAGE-RAGE axis in NASH-related HCC. PMID:26483867

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

    PubMed Central

    Hernanz, R; Martínez-Revelles, S; Palacios, R; Martín, A; Cachofeiro, V; Aguado, A; García-Redondo, L; Barrús, M T; de Batista, P R; Briones, A M; Salaices, M; Alonso, M J

    2015-01-01

    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. PMID:25712370

  15. Amygdala responses to salient social cues vary with oxytocin receptor genotype in youth

    PubMed Central

    Marusak, Hilary A.; Furman, Daniella J.; Kuruvadi, Nisha; Shattuck, David W.; Joshi, Shantanu H.; Joshi, Anand A.; Etkin, Amit; Thomason, Moriah E.

    2015-01-01

    Depression, anxiety, and posttraumatic stress disorder are linked to altered limbic morphology, dysregulated neuroendocrine function, and heightened amygdala responses to salient social cues. Oxytocin appears to be a potent modulator of amygdala reactivity and neuroendocrine responses to psychosocial stress. Given these stress regulatory effects, there is increasing interest in understanding the role of oxytocin in vulnerability to stress-related clinical disorders. The present study examines the impact of a common functional variant within the oxytocin receptor (OXTR) gene (rs2254298) on structure and function of the amygdala in a high-risk sample of urban, low-income, minority youth with a high incidence of early life stress (ELS). Compared to G/G homozygotes, youth carrying the OXTR A-allele showed increased amygdala volume, reduced behavioral performance, and heightened amygdala response during two functional magnetic resonance imaging (fMRI) tasks that involved viewing socially-relevant face stimuli. Higher amygdala response was related to ELS in A-alleles carriers but not G/G homozygotes. These findings underscore a series of relationships among a common oxytocin system gene variant, ELS exposure, and structure and function of the amygdala in early life. Heightened amygdala response to salient social cues in OXTR A-allele carriers may elevate risk for emotional psychopathology by increasing amygdala involvement in disambiguating environmental cues, particularly for individuals with ELS. PMID:26477647

  16. Neural correlate of autistic-like traits and a common allele in the oxytocin receptor gene

    PubMed Central

    Saito, Yuki; Suga, Motomu; Tochigi, Mamoru; Abe, Osamu; Yahata, Noriaki; Kawakubo, Yuki; Liu, Xiaoxi; Kawamura, Yoshiya; Sasaki, Tsukasa; Kasai, Kiyoto

    2014-01-01

    Sub-clinical autistic-like traits (ALTs) are continuously distributed in the general population and genetically linked to autism. Although identifying the neurogenetic backgrounds of ALTs might enhance our ability to identify those of autism, they are largely unstudied. Here, we have examined the neuroanatomical basis of ALTs and their association with the oxytocin receptor gene (OXTR) rs2254298A, a known risk allele for autism in Asian populations which has also been implicated in limbic–paralimbic brain structures. First, we extracted a four-factor structure of ALTs, as measured using the Autism-Spectrum Quotient, including ‘prosociality’, ‘communication’, ‘details/patterns’ and ‘imagination’ in 135 neurotypical adults (79 men, 56 women) to reduce the genetic heterogeneity of ALTs. Then, in the same population, voxel-based morphometry revealed that lower ‘prosociality’, which indicates strong ALTs, was significantly correlated to smaller regional grey matter volume in the right insula in males. Males with lower ‘prosociality’ also had less interregional structural coupling between the right insula and the ventral anterior cingulate cortex. Furthermore, males with OXTR rs2254298A had significantly smaller grey matter volume in the right insula. These results show that decreased volume of the insula is a neuroanatomical correlate of ALTs and a potential intermediate phenotype linking ALTs with OXTR in male subjects. PMID:23946005

  17. Social cognition, face processing, and oxytocin receptor single nucleotide polymorphisms in typically developing children.

    PubMed

    Slane, Mylissa M; Lusk, Laina G; Boomer, K B; Hare, Abby E; King, Margaret K; Evans, David W

    2014-07-01

    Recent research has provided evidence of a link between behavioral measures of social cognition (SC) and neural and genetic correlates. Differences in face processing and variations in the oxytocin receptor (OXTR) gene have been associated with SC deficits and autism spectrum disorder (ASD) traits. Much work has examined the qualitative differences between those with ASD and typically developing (TD) individuals, but very little has been done to quantify the natural variation in ASD-like traits in the typical population. The present study examines this variation in TD children using a multidimensional perspective involving behavior assessment, neural electroencephalogram (EEG) testing, and OXTR genotyping. Children completed a series of neurocognitive assessments, provided saliva samples for sequencing, and completed a face processing task while connected to an EEG. No clear pattern emerged for EEG covariates or genotypes for individual OXTR single nucleotide polymorphisms (SNPs). However, SNPs rs2254298 and rs53576 consistently interacted such that the AG/GG allele combination of these SNPs was associated with poorer performance on neurocognitive measures. These results suggest that neither SNP in isolation is risk-conferring, but rather that the combination of rs2254298(A/G) and rs53576(G/G) confers a deleterious effect on SC across several neurocognitive measures.

  18. Polymorphism of the Oxytocin Receptor Gene Modulates Behavioral and Attitudinal Trust among Men but Not Women.

    PubMed

    Nishina, Kuniyuki; Takagishi, Haruto; Inoue-Murayama, Miho; Takahashi, Hidehiko; Yamagishi, Toshio

    2015-01-01

    A relationship between the oxytocin receptor gene (OXTR) and behavioral and attitudinal trust has been suggested, but the nature of this relationship has not yet been established. We obtained behavioral trust data from 470 Japanese participants (242 women) aged 20-59 years, together with their levels of general trust and personality traits (NEO-FFI). Saliva buccal swabs were collected from 411 of these 470 participants and used for genotyping of OXTR rs53576. Our participants were found to have more AA alleles (40%) than GG alleles (12%). The GG men were more trusting and also rated higher on attitudinal trust than AA men, and this difference did not diminish when personality traits were controlled for. However, this pattern was not observed among women. In addition, controlling for attitudinal trust reduced the difference in behavioral trust among men to a non-significant level, but the difference in attitudinal trust remained significant when behavioral trust was controlled. These results indicate that the OXTR genotype affects attitudinal trust as part of an individual's relatively stable disposition, and further affects behavioral trust through changes in attitudinal trust.

  19. Impaired toll like receptor-7 and 9 induced immune activation in chronic spinal cord injured patients contributes to immune dysfunction

    PubMed Central

    Gungor, Bilgi; Kahraman, Tamer; Gursel, Mayda; Yilmaz, Bilge

    2017-01-01

    Reduced immune activation or immunosuppression is seen in patients withneurological diseases. Urinary and respiratory infections mainly manifested as septicemia and pneumonia are the most frequent complications following spinal cord injuries and they account for the majority of deaths. The underlying reason of these losses is believed to arise due to impaired immune responses to pathogens. Here, we hypothesized that susceptibility to infections of chronic spinal cord injured (SCI) patients might be due to impairment in recognition of pathogen associated molecular patterns and subsequently declining innate and adaptive immune responses that lead to immune dysfunction. We tested our hypothesis on healthy and chronic SCI patients with a level of injury above T-6. Donor PBMCs were isolated and stimulated with different toll like receptor ligands and T-cell inducers aiming to investigate whether chronic SCI patients display differential immune activation to multiple innate and adaptive immune cell stimulants. We demonstrate that SCI patients' B-cell and plasmacytoid dendritic cells retain their functionality in response to TLR7 and TLR9 ligand stimulation as they secreted similar levels of IL6 and IFNα. The immune dysfunction is not probably due to impaired T-cell function, since neither CD4+ T-cell dependent IFNγ producing cell number nor IL10 producing regulatory T-cells resulted different outcomes in response to PMA-Ionomycin and PHA-LPS stimulation, respectively. We showed that TLR7 dependent IFNγ and IP10 levels and TLR9 mediated APC function reduced substantially in SCI patients compared to healthy subjects. More importantly, IP10 producing monocytes were significantly fewer compared to healthy subjects in response to TLR7 and TLR9 stimulation of SCI PBMCs. When taken together this work implicated that these defects could contribute to persistent complications due to increased susceptibility to infections of chronic SCI patients. PMID:28170444

  20. CRF receptor type 2 neurons in the posterior bed nucleus of the stria terminalis critically contribute to stress recovery.

    PubMed

    Henckens, M J A G; Printz, Y; Shamgar, U; Dine, J; Lebow, M; Drori, Y; Kuehne, C; Kolarz, A; Eder, M; Deussing, J M; Justice, N J; Yizhar, O; Chen, A

    2016-08-23

    The bed nucleus of the stria terminalis (BNST) is critical in mediating states of anxiety, and its dysfunction has been linked to stress-related mental disease. Although the anxiety-related role of distinct subregions of the anterior BNST was recently reported, little is known about the contribution of the posterior BNST (pBNST) to the behavioral and neuroendocrine responses to stress. Previously, we observed abnormal expression of corticotropin-releasing factor receptor type 2 (CRFR2) to be associated with post-traumatic stress disorder (PTSD)-like symptoms. Here, we found that CRFR2-expressing neurons within the pBNST send dense inhibitory projections to other stress-related brain regions (for example, the locus coeruleus, medial amygdala and paraventricular nucleus), implicating a prominent role of these neurons in orchestrating the neuroendocrine, autonomic and behavioral response to stressful situations. Local CRFR2 activation by urocortin 3 depolarized the cells, increased the neuronal input resistance and increased firing of action potentials, indicating an enhanced excitability. Furthermore, we showed that CRFR2-expressing neurons within the pBNST are critically involved in the modulation of the behavioral and neuroendocrine response to stress. Optogenetic activation of CRFR2 neurons in the pBNST decreased anxiety, attenuated the neuroendocrine stress response, ameliorated stress-induced anxiety and impaired the fear memory for the stressful event. Moreover, activation following trauma exposure reduced the susceptibility for PTSD-like symptoms. Optogenetic inhibition of pBNST CRFR2 neurons yielded opposite effects. These data indicate the relevance of pBNST activity for adaptive stress recovery.Molecular Psychiatry advance online publication, 23 August 2016; doi:10.1038/mp.2016.133.

  1. Fosb gene products contribute to excitotoxic microglial activation by regulating the expression of complement C5a receptors in microglia

    PubMed Central

    Nomaru, Hiroko; Sakumi, Kunihiko; Katogi, Atsuhisa; Ohnishi, Yoshinori N; Kajitani, Kosuke; Tsuchimoto, Daisuke; Nestler, Eric J.; Nakabeppu, Yusaku

    2014-01-01

    The Fosb gene encodes subunits of the activator protein-1 transcription factor complex. Two mature mRNAs, Fosb and ΔFosb, encoding full-length FOSB and ΔFOSB proteins respectively, are formed by alternative splicing of Fosb mRNA. Fosb products are expressed in several brain regions. Moreover, Fosb-null mice exhibit depressive-like behaviors and adult-onset spontaneous epilepsy, demonstrating important roles in neurological and psychiatric disorders. Study of Fosb products has focused almost exclusively on neurons; their function in glial cells remains to be explored. In this study, we found that microglia express equivalent levels of Fosb and ΔFosb mRNAs to hippocampal neurons and, using microarray analysis, we identified six microglial genes whose expression is dependent on Fosb products. Of these genes, we focused on C5ar1 and C5ar2, which encode receptors for complement C5a. In isolated Fosb-null microglia, chemotactic responsiveness toward the truncated form of C5a was significantly lower than that in wild-type cells. Fosb-null mice were significantly resistant to kainate-induced seizures compared with wild-type mice. C5ar1 mRNA levels and C5aR1 immunoreactivity were increased in wild-type hippocampus 24 hours after kainate administration; however, such induction was significantly reduced in Fosb-null hippocampus. Furthermore, microglial activation after kainate administration was significantly diminished in Fosb-null hippocampus, as shown by significant reductions in CD68 immunoreactivity, morphological change and reduced levels of Il6 and Tnf mRNAs, although no change in the number of Iba-1-positive cells was observed. These findings demonstrate that, under excitotoxicity, Fosb products contribute to a neuroinflammatory response in the hippocampus through regulation of microglial C5ar1 and C5ar2 expression. PMID:24771617

  2. Pharmacological evidence that a failure to recruit NMDA receptors contributes to impaired fear extinction retention in adolescent rats.

    PubMed

    Baker, Kathryn D; Richardson, Rick

    2016-11-01

    Adolescents, both humans and rodents, exhibit a marked impairment in extinction of fear relative to younger and older groups which could be caused by a failure to efficiently recruit NMDA receptors (NMDARs) in adolescence. It is well-established that systemic administration of NMDAR antagonists (e.g., MK801) before extinction training impairs the retention of extinction in adult and juvenile rodents, but it is unknown whether this is also the case for adolescents. Therefore, in the present study we investigated the effect of pharmacologically manipulating the NMDAR on extinction retention in adolescent rats. When extinction retention is typically impaired (i.e., after one session of extinction training) adolescent male rats given d-cycloserine (a partial NMDAR agonist) showed enhanced extinction retention relative to saline-treated animals while animals given MK801 (a non-competitive antagonist) did not exhibit any further impairment of extinction retention relative to the controls. In a further two experiments we demonstrated that when two sessions of extinction training separated by either 4 or 24h intervals were given to adolescent rats, saline-treated animals exhibited good extinction retention and the animals given MK801 before the second session exhibited impaired extinction retention. These findings suggest that extinction in adolescence does not initially involve NMDARs and this is a likely mechanism that contributes to the impaired fear inhibition observed at this age. However, NMDARs appear to be recruited with extended extinction training or after administration of a partial agonist, both of which lead to effective extinction retention.

  3. A rice lectin receptor-like kinase that is involved in innate immune responses also contributes to seed germination.

    PubMed

    Cheng, Xiaoyan; Wu, Yan; Guo, Jianping; Du, Bo; Chen, Rongzhi; Zhu, Lili; He, Guangcun

    2013-11-01

    Seed germination and innate immunity both have significant effects on plant life spans because they control the plant's entry into the ecosystem and provide defenses against various external stresses, respectively. Much ecological evidence has shown that seeds with high vigor are generally more tolerant of various environmental stimuli in the field than those with low vigor. However, there is little genetic evidence linking germination and immunity in plants. Here, we show that the rice lectin receptor-like kinase OslecRK contributes to both seed germination and plant innate immunity. We demonstrate that knocking down the OslecRK gene depresses the expression of α-amylase genes, reducing seed viability and thereby decreasing the rate of seed germination. Moreover, it also inhibits the expression of defense genes, and so reduces the resistance of rice plants to fungal and bacterial pathogens as well as herbivorous insects. Yeast two-hybrid and co-immunoprecipitation experiments revealed that OslecRK interacts with an actin-depolymerizing factor (ADF) in vivo via its kinase domain. Moreover, the rice adf mutant exhibited a reduced seed germination rate due to the suppression of α-amylase gene expression. This mutant also exhibited depressed immune responses and reduced resistance to biotic stresses. Our results thus provide direct genetic evidence for a common physiological pathway connecting germination and immunity in plants. They also partially explain the common observation that high-vigor seeds often perform well in the field. The dual effects of OslecRK may be indicative of progressive adaptive evolution in rice.

  4. Chronic pain after lower abdominal surgery: do catechol-O-methyl transferase/opioid receptor μ-1 polymorphisms contribute?

    PubMed Central

    2013-01-01

    Background Preoperative pain, type of operation and anesthesia, severity of acute postoperative pain, and psychosocial factors have been identified as risk factors for chronic postsurgical pain (CPP). Recently, it has been suggested that genetic factors also contribute to CPP. In this study, we aimed to determine whether the catechol-O-methyl transferase (COMT) and opioid receptor μ-1 (OPRM1) common functional polymorphisms rs4680 and rs1799971 were associated with the incidence, intensity, or duration of CPP in patients after lower abdominal surgery. Methods One hundred and two patients with American Society of Anesthesiologists (ASA) physical status I/II underwent either abdominal radical prostatectomy (n = 45) or hysterectomy (n = 57). The incidences of CPP in the pelvic and scar areas were evaluated in all patients three months after surgery. Results Thirty-five (34.3%) patients experienced CPP after lower abdominal surgery. Within this group, six (17.1%) patients demonstrated symptoms of neuropathic pain. For COMT rs4680, 22 (21.6%) patients had Met158Met, 55 (53.9%) patients had Val158Met, and 25 (24.5%) patients had Val158Val. No association was found between CPP phenotypes (incidence, intensity, and duration) and different rs4680 genotypes. For OPRM1 rs1799971, only CPP patients carrying at least one copy of the G allele had higher pain intensity than A118A carriers (p=0.02). No associations with other phenotypes were found. No combined effect of COMT/OPRM1 polymorphisms on CPP phenotypes was observed. Conclusions OPRM1 genotype influences CPP following lower abdominal surgery. COMT didn’t affect CPP, suggesting its potential modality-specific effects on human pain. PMID:23566343

  5. The vitamin D receptor inhibits the respiratory chain, contributing to the metabolic switch that is essential for cancer cell proliferation.

    PubMed

    Consiglio, Marco; Destefanis, Michele; Morena, Deborah; Foglizzo, Valentina; Forneris, Mattia; Pescarmona, Gianpiero; Silvagno, Francesca

    2014-01-01

    We recently described the mitochondrial localization and import of the vitamin D receptor (VDR) in actively proliferating HaCaT cells for the first time, but its role in the organelle remains unknown. Many metabolic intermediates that support cell growth are provided by the mitochondria; consequently, the identification of proteins that regulate mitochondrial metabolic pathways is of great interest, and we sought to understand whether VDR may modulate these pathways. We genetically silenced VDR in HaCaT cells and studied the effects on cell growth, mitochondrial metabolism and biosynthetic pathways. VDR knockdown resulted in robust growth inhibition, with accumulation in the G0G1 phase of the cell cycle and decreased accumulation in the M phase. The effects of VDR silencing on proliferation were confirmed in several human cancer cell lines. Decreased VDR expression was consistently observed in two different models of cell differentiation. The impairment of silenced HaCaT cell growth was accompanied by sharp increases in the mitochondrial membrane potential, which sensitized the cells to oxidative stress. We found that transcription of the subunits II and IV of cytochrome c oxidase was significantly increased upon VDR silencing. Accordingly, treatment of HaCaT cells with vitamin D downregulated both subunits, suggesting that VDR may inhibit the respiratory chain and redirect TCA intermediates toward biosynthesis, thus contributing to the metabolic switch that is typical of cancer cells. In order to explore this hypothesis, we examined various acetyl-CoA-dependent biosynthetic pathways, such as the mevalonate pathway (measured as cholesterol biosynthesis and prenylation of small GTPases), and histone acetylation levels; all of these pathways were inhibited by VDR silencing. These data provide evidence of the role of VDR as a gatekeeper of mitochondrial respiratory chain activity and a facilitator of the diversion of acetyl-CoA from the energy-producing TCA cycle

  6. Toll-like receptor 4 contributes to chronic itch, alloknesis and spinal astrocyte activation in male mice

    PubMed Central

    Liu, Tong; Han, Qingjian; Chen, Gang; Huang, Ya; Zhao, Lin-Xia; Berta, Temugin; Gao, Yong-Jing; Ji, Ru-Rong

    2016-01-01

    Increasing evidence suggests that Toll-like receptor 4 (TLR4) contributes importantly to spinal cord glial activation and chronic pain sensitization; however, its unique role in acute and chronic itch is unclear. In this study, we investigated the involvement of TLR4 in acute and chronic itch models in male mice using both transgenic and pharmacological approaches. Tlr4−/− mice exhibited normal acute itch induced by compound 48/80 and chloroquine, but these mice showed substantial reductions in scratching in chronic itch models of dry skin, induced by acetone and diethyether followed by water (AEW), contact dermatitis, and allergic contact dermatitis on the neck. Intrathecal (spinal) inhibition of TLR4 with lipopolysaccharide Rhodobacter sphaeroides (LPS-RS) did not affect acute itch but suppressed AEW-induced chronic itch. Compound 48/80 and AEW also produced robust alloknesis, a touch-elicited itch in wild-type mice, which was suppressed by intrathecal LPS-RS and Tlr4−/− deletion. AEW induced persistent upregulation of Tlr4 mRNA and increased TLR4 expression in GFAP-expressing astrocytes in spinal cord dorsal horn. AEW also induced TLR4-dependent astrogliosis (GFAP upregulation) in spinal cord. Intrathecal injection of astroglial inhibitor L-α-aminoadipate reduced AEW-induced chronic itch and alloknesis without affecting acute itch. Spinal TLR4 was also necessary for AEW-induced chronic itch in the cheek model. Interestingly, scratching plays an essential role in spinal astrogliosis, since AEW-induced astrogliosis was abrogated by putting Elizabethan Collars on the neck to prevent scratching the itchy skin. Our findings suggest that spinal TLR4 signaling is important for spinal astrocyte activation and astrogliosis that may underlie alloknesis and chronic itch. PMID:26645545

  7. Toll-like receptor 4 contributes to chronic itch, alloknesis, and spinal astrocyte activation in male mice.

    PubMed

    Liu, Tong; Han, Qingjian; Chen, Gang; Huang, Ya; Zhao, Lin-Xia; Berta, Temugin; Gao, Yong-Jing; Ji, Ru-Rong

    2016-04-01

    Increasing evidence suggests that Toll-like receptor 4 (TLR4) contributes importantly to spinal cord glial activation and chronic pain sensitization; however, its unique role in acute and chronic itch is unclear. In this study, we investigated the involvement of TLR4 in acute and chronic itch models in male mice using both transgenic and pharmacological approaches. Tlr4 mice exhibited normal acute itch induced by compound 48/80 and chloroquine, but these mice showed substantial reductions in scratching in chronic itch models of dry skin, induced by acetone and diethylether followed by water (AEW), contact dermatitis, and allergic contact dermatitis on the neck. Intrathecal (spinal) inhibition of TLR4 with lipopolysaccharide Rhodobacter sphaeroides did not affect acute itch but suppressed AEW-induced chronic itch. Compound 48/80 and AEW also produced robust alloknesis, a touch-elicited itch in wild-type mice, which was suppressed by intrathecal lipopolysaccharide R sphaeroides and Tlr4 deletion. Acetone and diethylether followed by water induced persistent upregulation of Tlr4 mRNA and increased TLR4 expression in GFAP-expressing astrocytes in spinal cord dorsal horn. Acetone and diethylether followed by water also induced TLR4-dependent astrogliosis (GFAP upregulation) in spinal cord. Intrathecal injection of astroglial inhibitor L-α-aminoadipate reduced AEW-induced chronic itch and alloknesis without affecting acute itch. Spinal TLR4 was also necessary for AEW-induced chronic itch in the cheek model. Interestingly, scratching plays an essential role in spinal astrogliosis because AEW-induced astrogliosis was abrogated by putting Elizabethan collars on the neck to prevent scratching the itchy skin. Our findings suggest that spinal TLR4 signaling is important for spinal astrocyte activation and astrogliosis that may underlie alloknesis and chronic itch.

  8. Peroxisome proliferator-activated receptor α (PPARα) contributes to control of melanogenesis in B16 F10 melanoma cells.

    PubMed

    Grabacka, Maja; Wieczorek, Justyna; Michalczyk-Wetula, Dominika; Malinowski, Michel; Wolan, Norbert; Wojcik, Katarzyna; Plonka, Przemyslaw M

    2017-04-01

    Recent studies revealed the cooperation between peroxisome proliferator-activated receptor gamma (PPARγ) and α-MSH signaling, which results in enhanced melanogenesis in melanocytes and melanoma cells. However, the agonists of PPARα, such as fenofibrate, exert depigmenting effect. Therefore, we aimed to check how the PPARα expression level affects the antimelanogenic activity of fenofibrate and whether PPARα modulates melanogenesis independently of its agonist. To answer these questions, we used three B16 F10-derived cell lines, which varied in the PPARα expression level and were developed by stable transfection with plasmids driving shRNA-based PPARα silencing or overexpression of PPARα-emerald GFP fusion protein. Melanin contents were assessed with electron paramagnetic resonance spectroscopy along with color component image analysis-a novel approach to pigment content characteristics in melanoma cells. B16 F10 wt and Ctrl shRNA lines showed intermediate pigmentation, whereas the pigmentation of the B16 F10-derived cell lines was inversely correlated with the PPARα expression level. We observed that cells overexpressing PPARα were almost amelanotic and cells with reduced PPARα protein level were heavily melanized. Furthermore, fenofibrate down-regulated the melanogenic apparatus (MITF, tyrosinase, and tyrosinase-related proteins) in the cells with the regular PPARα expression level resulting in their visibly lower total melanin content in all the cell lines. From these observations, we conclude that fenofibrate works as a strong depigmenting agent, which acts independently of PPARα, but in an additive fashion. Our results also indicate that alterations in PGC-1a acetylation and expression level might contribute to the regulation of melanogenesis by PPARα and fenofibrate.

  9. Decreased expression of vitamin D receptor may contribute to the hyperimmune status of patients with acquired aplastic anemia.

    PubMed

    Yu, Wei; Ge, Meili; Lu, Shihong; Shi, Jun; Feng, Sizhou; Li, Xingxin; Zhang, Jizhou; Wang, Min; Huang, Jinbo; Shao, Yingqi; Huang, Zhendong; Zhang, Jing; Nie, Neng; Zheng, Yizhou

    2016-05-01

    Acquired aplastic anemia (AA) is an immune-mediated bone marrow failure syndrome. 1α,25-Dihydroxyvitamin D3 [1,25(OH)2 D3 ], the biologically active metabolite of vitamin D, is a critical modulator of immune response via binding with vitamin D receptor (VDR). Previous studies have established that 1,25(OH)2 D3 and VDR were involved in the pathogenesis of some autoimmune diseases. In this study, we evaluated the involvement of 1,25(OH)2 D3 and VDR on T-cell responses in AA. Plasma 25(OH)D3 levels were comparable between patients with AA and healthy controls. Surprisingly, VDR mRNA was significantly lower in untreated patients with AA than in healthy controls. Subsequent in vitro experiments revealed that 1,25(OH)2 D3 treatment suppressed the proliferation of lymphocytes and inhibited the secretion of interferon-γ, tumor necrosis factor-α, and interleukin-17A, meanwhile promoting the production of transforming growth factor-β1 in patients with AA. Moreover, 1,25(OH)2 D3 inhibited the differentiation of type 1 and Th17 cells but induced the differentiation of type 2 and regulatory T cells. Interestingly, VDR mRNA was elevated in healthy controls after 1,25(OH)2 D3 treatment, but not in patients with AA. In conclusion, decreased expression of VDR might contribute to the hyperimmune status of AA and appropriate vitamin D supplementation could partly correct the immune dysfunction by strengthening signal transduction through VDR in patients with AA.

  10. Initial reduction of oxidative stress by angiotensin receptor blocker contributes long term outcomes after percutaneous coronary intervention

    PubMed Central

    Noro, Tadanori; Takehara, Naofumi; Sumitomo, Kazuhiro; Takeuchi, Toshiharu; Ishii, Yoshinao; Kato, Jun-ichi; Kawabe, Jun-ichi; Hasebe, Naoyuki

    2014-01-01

    Background: It remains unclear whether administration of ARB with reactive oxygen species (ROS) scavenging effects improves the prognosis of patients undergoing PCI. Objectives: This study investigated whether the pre-intervention antioxidant effect of angiotensin receptor blocker (ARB) affects long-term outcomes in patients after successful percutaneous coronary intervention (PCI) without early adverse events. Methods: Fifty-two patients who underwent elective PCI were randomly assigned for treatment with or without ARB, which was administered within 48 hours before PCI. ROS levels in mononuclear cells (MNCs) and serum superoxide dismutase (SOD) activity were measured pre-PCI and 6 months post-PCI. After exclusion of unexpected early adverse events during angiographic follow-up period, the long-term outcome (major adverse cerebro-cardiovascular event; MACCE) was assessed in eligible patients. Results: Forty-three patients (non-ARB n = 22, ARB n = 21) were followed up in this study. During angiographic follow-up period, ROS formation in MNCs was significantly increased in the non-ARB group (from 29.4 [21.6-35.2] to 37.2 [30.7-45.1] arbitrary units; p = 0.031) compared to that in the ARB group. Meanwhile, SOD activity was significantly impaired in the non-ARB group alone (from 24.0 ± 17.0 to 16.3 ± 13.8%, p = 0.004). During the follow-up period (median, 63.3 months), MACCEs were observed in 6 patients. The cumulative event ratio of MACCE was significantly higher in the non-ARB group than in the ARB group (p = 0.018). Conclusions: Concomitant administration of ARB effectively reduced ROS production of PCI patients during angiographic follow-up period. Initial ROS inhibition following ARB administration may contribute to improvement of worse outcomes in patients who have undergone successful PCI. PMID:25628957

  11. The Vitamin D Receptor Inhibits the Respiratory Chain, Contributing to the Metabolic Switch that Is Essential for Cancer Cell Proliferation

    PubMed Central

    Morena, Deborah; Foglizzo, Valentina; Forneris, Mattia; Pescarmona, Gianpiero; Silvagno, Francesca

    2014-01-01

    We recently described the mitochondrial localization and import of the vitamin D receptor (VDR) in actively proliferating HaCaT cells for the first time, but its role in the organelle remains unknown. Many metabolic intermediates that support cell growth are provided by the mitochondria; consequently, the identification of proteins that regulate mitochondrial metabolic pathways is of great interest, and we sought to understand whether VDR may modulate these pathways. We genetically silenced VDR in HaCaT cells and studied the effects on cell growth, mitochondrial metabolism and biosynthetic pathways. VDR knockdown resulted in robust growth inhibition, with accumulation in the G0G1 phase of the cell cycle and decreased accumulation in the M phase. The effects of VDR silencing on proliferation were confirmed in several human cancer cell lines. Decreased VDR expression was consistently observed in two different models of cell differentiation. The impairment of silenced HaCaT cell growth was accompanied by sharp increases in the mitochondrial membrane potential, which sensitized the cells to oxidative stress. We found that transcription of the subunits II and IV of cytochrome c oxidase was significantly increased upon VDR silencing. Accordingly, treatment of HaCaT cells with vitamin D downregulated both subunits, suggesting that VDR may inhibit the respiratory chain and redirect TCA intermediates toward biosynthesis, thus contributing to the metabolic switch that is typical of cancer cells. In order to explore this hypothesis, we examined various acetyl-CoA-dependent biosynthetic pathways, such as the mevalonate pathway (measured as cholesterol biosynthesis and prenylation of small GTPases), and histone acetylation levels; all of these pathways were inhibited by VDR silencing. These data provide evidence of the role of VDR as a gatekeeper of mitochondrial respiratory chain activity and a facilitator of the diversion of acetyl-CoA from the energy-producing TCA cycle

  12. Protease-Activated Receptor-2 Activation Contributes to House Dust Mite-Induced IgE Responses in Mice

    PubMed Central

    Post, Sijranke; Heijink, Irene H.; Petersen, Arjen H.; de Bruin, Harold G.; van Oosterhout, Antoon J. M.; Nawijn, Martijn C.

    2014-01-01

    Aeroallergens such as house dust mite (HDM), cockroach, and grass or tree pollen are innocuous substances that can induce allergic sensitization upon inhalation. The serine proteases present in these allergens are thought to activate the protease-activated receptor (PAR)-2, on the airway epithelium, thereby potentially inducing allergic sensitization at the expense of inhalation tolerance. We hypothesized that the proteolytic activity of allergens may play an important factor in the allergenicity to house dust mite and is essential to overcome airway tolerance. Here, we aimed to investigate the role of PAR-2 activation in allergic sensitization and HDM-induced allergic airway inflammation. In our study, Par-2 deficient mice were treated with two different HDM extracts containing high and low serine protease activities twice a week for a period of 5 weeks. We determined airway inflammation through quantification of percentages of mononuclear cells, eosinophils and neutrophils in the bronchial alveolar lavage fluid and measured total IgE and HDM-specific IgE and IgG1 levels in serum. Furthermore, Th2 and pro-inflammatory cytokines including IL-5, IL-13, Eotaxin-1, IL-17, KC, Chemokine (C-C motif) ligand 17 (CCL17) and thymic stromal lymphopoietin (TSLP), were measured in lung tissue homogenates. We observed that independent of the serine protease content, HDM was able to induce elevated levels of eosinophils and neutrophils in the airways of both wild-type (WT) and Par-2 deficient mice. Furthermore, we show that induction of pro-inflammatory cytokines by HDM exposure is independent of Par-2 activation. In contrast, serine protease activity of HDM does contribute to enhanced levels of total IgE, but not HDM-specific IgE. We conclude that, while Par-2 activation contributes to the development of IgE responses, it is largely dispensable for the HDM-induced induction of pro-inflammatory cytokines and airway inflammation in an experimental mouse model of HDM

  13. Endogenous activation of nAChRs and NMDA receptors contributes to the excitability of CA1 stratum radiatum interneurons in rat hippocampal slices: effects of kynurenic acid.

    PubMed

    Alkondon, Manickavasagom; Pereira, Edna F R; Albuquerque, Edson X

    2011-10-15

    CA1 stratum radiatum interneurons (SRIs) express α7 nicotinic receptors (nAChRs) and receive inputs from glutamatergic neurons/axons that express α3β4β2 nAChRs. To test the hypothesis that endogenously active α7 and/or α3β4β2 nAChRs control the excitability of CA1 SRIs in the rat hippocampus, we examined the effects of selective receptor antagonists on spontaneous fast current transients (CTs) recorded from these interneurons under cell-attached configuration. The frequency of CTs, which represent action potentials, increased in the absence of extracellular Mg(2+) and decreased in the presence of the α3β4β2 nAChR antagonist mecamylamine (3 μM) or the NMDA receptor antagonist APV (50 μM). However, it was unaffected by the α7 nAChR antagonist MLA (10 nM) or the AMPA receptor antagonist CNQX (10 μM). Thus, in addition to synaptically and tonically activated NMDA receptors, α3β4β2 nAChRs that are present on glutamatergic axons/neurons synapsing onto SRIs and are activated by basal levels of acetylcholine contribute to the maintenance of the excitability of these interneurons. Kynurenic acid (KYNA), an astrocyte-derived kynurenine metabolite whose levels are increased in the brains of patients with schizophrenia, also controls the excitability of SRIs. At high micromolar concentrations, KYNA, acting primarily as an NMDA receptor antagonist, decreased the CT frequency recorded from the interneurons. At 2 μM, KYNA reduced the CA1 SRI excitability via mechanisms independent of NMDA receptor block. KYNA-induced reduction of excitability of SRIs may contribute to sensory gating deficits that have been attributed to deficient hippocampal GABAergic transmission and high levels of KYNA in the brain of patients with schizophrenia.

  14. Spinal prostaglandin E receptors of the EP2 subtype and the glycine receptor alpha3 subunit, which mediate central inflammatory hyperalgesia, do not contribute to pain after peripheral nerve injury or formalin injection.

    PubMed

    Hösl, Katharina; Reinold, Heiko; Harvey, Robert J; Müller, Ulrike; Narumiya, Shuh; Zeilhofer, Hanns Ulrich

    2006-12-15

    Inflammation, peripheral nerve injury and chemical irritants can cause central sensitization in pain pathways. Prostaglandins produced in the CNS induce central sensitization during inflammation mainly by relieving nociceptive neurons from glycinergic inhibition. We have recently identified spinal prostaglandin E receptors of the EP2 subtype (EP2 receptors) and the glycine receptor alpha3 subunit (GlyR alpha3) as signal transduction elements involved in the generation of central inflammatory hyperalgesia. It is however still unknown to what extent inhibition of glycine receptors by PGE2 contributes to neuropathic or chemically induced pain. To address this question, we have analyzed mice deficient in the EP2 receptor (EP2-/- mice) or in the GlyR alpha3 subunit (GlyR alpha3-/- mice) using the chronic constriction injury (CCI) model of neuropathic pain and the formalin test. We found that EP2-/- mice and GlyR alpha3-/- mice develop thermal and mechanical hyperalgesia in the CCI model indistinguishable from that seen in wild-type mice. In the formalin test, EP2-/- mice, but not GlyR alpha3-/- mice, exhibited reduced nocifensive behavior. The lack of a phenotype in GlyR alpha3-/- mice together with the absence of a facilitating effect of intrathecal PGE2 on formalin-induced nociception in wild-type mice suggests that peripheral rather than spinal EP2 receptors are involved. These results indicate that inhibition of glycinergic neurotransmission by EP2 receptor activation does not contribute to pain following peripheral nerve injury or chemical irritation with formalin. Our results thus provide further evidence that inflammatory hyperalgesia and neuropathic pain involve different mechanisms of central sensitization.

  15. Endothelin-1 contributes to endothelial dysfunction and enhanced vasoconstriction through augmented superoxide production in penile arteries from insulin-resistant obese rats: role of ETA and ETB receptors

    PubMed Central

    Sánchez, A; Martínez, P; Muñoz, M; Benedito, S; García-Sacristán, A; Hernández, M; Prieto, D

    2014-01-01

    Background and Purpose We assessed whether endothelin-1 (ET-1) inhibits NO and contributes to endothelial dysfunction in penile arteries in a model of insulin resistance-associated erectile dysfunction (ED). Experimental Approach Vascular function was assessed in penile arteries, from obese (OZR) and lean (LZR) Zucker rats, mounted in microvascular myographs. Changes in basal and stimulated levels of superoxide (O2−) were detected by lucigenin-enhanced chemiluminescence and ET receptor expression was determined by immunohistochemistry. Key Results ET-1 stimulated acute O2− production that was blunted by tempol and the NADPH oxidase inhibitor, apocynin, but markedly enhanced in obese animals. ET-1 inhibited the vasorelaxant effects of ACh and of the NO donor S-nitroso-N-acetyl-DL-penicillamine in arteries from both LZR and OZR. Selective ETA (BQ123) or ETB receptor (BQ788) antagonists reduced both basal and ET-1-stimulated superoxide generation and reversed ET-1-induced inhibition of NO-mediated relaxations in OZR, while only BQ-123 antagonized ET-1 actions in LZR. ET-1-induced vasoconstriction was markedly enhanced by NO synthase blockade and reduced by endothelium removal and apocynin. In endothelium-denuded penile arteries, apocynin blunted augmented ET-1-induced contractions in OZR. Both ETA and ETB receptors were expressed in smooth muscle and the endothelial layer and up-regulated in arteries from OZR. Conclusions and Implications ET-1 stimulates ETA-mediated NADPH oxidase-dependent ROS generation, which inhibits endothelial NO bioavailability and contributes to ET-1-induced contraction in healthy penile arteries. Enhanced vascular expression of ETB receptors contributes to augmented ROS production, endothelial dysfunction and increased vasoconstriction in erectile tissue from insulin-resistant obese rats. Hence, antagonism of ETB receptors might improve the ED associated with insulin-resistant states. PMID:25091502

  16. The G protein-coupled receptor GPRC5B contributes to neurogenesis in the developing mouse neocortex.

    PubMed

    Kurabayashi, Nobuhiro; Nguyen, Minh Dang; Sanada, Kamon

    2013-11-01

    Neural progenitor cells in the developing brain give rise to neurons and glia. Multiple extrinsic signalling molecules and their cognate membrane receptors have been identified to control neural progenitor fate. However, a role for G protein-coupled receptors in cell fate decisions in the brain remains largely putative. Here we show that GPRC5B, which encodes an orphan G protein-coupled receptor, is present in the ventricular surface of cortical progenitors in the mouse developing neocortex and is required for their neuronal differentiation. GPRC5B-depleted progenitors fail to adopt a neuronal fate and ultimately become astrocytes. Furthermore, GPRC5B-mediated signalling is associated with the proper regulation of β-catenin signalling, a pathway crucial for progenitor fate decision. Our study uncovers G protein-coupled receptor signalling in the neuronal fate determination of cortical progenitors.

  17. Contribution of the Purinergic Receptor P2X7 to Development of Lung Immunopathology during Influenza Virus Infection

    PubMed Central

    Ermler, Megan E.; Schotsaert, Michael; Gonzalez, Ma G.; Gillespie, Virginia; Lim, Jean K.; García-Sastre, Adolfo

    2017-01-01

    ABSTRACT An exacerbated immune response is one of the main causes of influenza-induced lung damage during infection. The molecular mechanisms regulating the fate of the initial immune response to infection, either as a protective response or as detrimental immunopathology, are not well understood. The purinergic receptor P2X7 is an ionotropic nucleotide-gated ion channel receptor expressed on immune cells that has been implicated in induction and maintenance of excessive inflammation. Here, we analyze the role of this receptor in a mouse model of influenza virus infection using a receptor knockout (KO) mouse strain. Our results demonstrate that the absence of the P2X7 receptor results in a better outcome to influenza virus infection characterized by reduced weight loss and increased survival upon experimental influenza challenge compared to wild-type mice. This effect was not virus strain specific. Overall lung pathology and apoptosis were reduced in virus-infected KO mice. Production of proinflammatory cytokines and chemokines such as interleukin-10 (IL-10), gamma interferon (IFN-γ), and CC chemokine ligand 2 (CCL2) was also reduced in the lungs of the infected KO mice. Infiltration of neutrophils and depletion of CD11b+ macrophages, characteristic of severe influenza virus infection in mice, were lower in the KO animals. Together, these results demonstrate that activation of the P2X7 receptor is involved in the exacerbated immune response observed during influenza virus infection. PMID:28351919

  18. Spinal 5-HT3 receptors mediate descending facilitation and contribute to behavioral hypersensitivity via a reciprocal neuron-glial signaling cascade

    PubMed Central

    2014-01-01

    Background It has been recently recognized that the descending serotonin (5-HT) system from the rostral ventromedial medulla (RVM) in the brainstem and the 5-HT3 receptor subtype in the spinal dorsal horn are involved in enhanced descending pain facilitation after tissue and nerve injury. However, the mechanisms underlying the activation of the 5-HT3 receptor and its contribution to facilitation of pain remain unclear. Results In the present study, activation of spinal 5-HT3 receptors by intrathecal injection of a selective 5-HT3 receptor agonist SR 57227 induced spinal glial hyperactivity, neuronal hyperexcitability and pain hypersensitivity in rats. We found that there was neuron-to-microglia signaling via the chemokine fractalkine, microglia to astrocyte signaling via cytokine IL-18, astrocyte to neuronal signaling by IL-1β, and enhanced activation of NMDA receptors in the spinal dorsal horn. Glial hyperactivation in spinal dorsal horn after hindpaw inflammation was also attenuated by molecular depletion of the descending 5-HT system by intra-RVM Tph-2 shRNA interference. Conclusions These findings offer new insights into the cellular and molecular mechanisms at the spinal level responsible for descending 5-HT-mediated pain facilitation during the development of persistent pain after tissue and nerve injury. New pain therapies should focus on prime targets of descending facilitation-induced glial involvement, and in particular the blocking of intercellular signaling transduction between neurons and glia. PMID:24913307

  19. EphrinB-EphB receptor signaling contributes to neuropathic pain by regulating neural excitability and spinal synaptic plasticity in rats.

    PubMed

    Song, Xue-Jun; Zheng, Ji-Hong; Cao, Jun-Li; Liu, Wen-Tao; Song, Xue-Song; Huang, Zhi-Jiang

    2008-09-30

    Bidirectional signaling between ephrins and Eph receptor tyrosine kinases was first found to play important roles during development, but recently has been implicated in synaptic plasticity and pain processing in the matured nervous system. We show that ephrinB-EphB receptor signaling plays a critical role is induction and maintenance of neuropathic pain by regulating neural excitability and synaptic plasticity in the dorsal root ganglion (DRG) and the spinal dorsal horn (DH). Intrathecal application of blocking reagents for EphB-receptors, EphB1-Fc and EphB2-Fc chimeras inhibits the induction and maintenance of nerve injury-induced thermal hyperalgesia and mechanical allodynia. These blockers also prevent and suppress the nerve injury-induced hyperexcitability of nociceptive small DRG neurons, sensitization of DH neurons and long-term potentiation (LTP) of synapses between C fibers and DH neurons. In naïve, uninjured animals intrathecal administration of EphB-receptor activators ephrinB1-Fc and ephrinB2-Fc, respectively, induces thermal hypersensitivity and lowers the threshold for LTP, while EphB1-Fc prevents induction of the LTP. Western Blot analysis shows that nerve injury triggers an upregulation of the ephrinB1 and EphB1 receptor proteins in DRG and the spinal cord. These results indicate that, by regulating excitability of nociceptive-related neurons in DRG and DH and the synaptic plasticity at the spinal level, ephrinB-EphB receptor signaling contributes to neuropathic pain. This novel role for ephrinB-EphB receptor signaling suggests that these molecules may be useful therapeutic targets for treating pain after nerve injury.

  20. Muscarinic acetylcholine receptors in the nucleus accumbens core and shell contribute to cocaine priming-induced reinstatement of drug seeking

    PubMed Central

    Yee, Judy; Famous, Katie R.; Hopkins, Thomas J.; McMullen, Michael C.; Pierce, R. Christopher; Schmidt, Heath D.

    2011-01-01

    Muscarinic acetylcholine receptors in the nucleus accumbens play an important role in mediating the reinforcing effects of cocaine. However, there is a paucity of data regarding the role of accumbal muscarinic acetylcholine receptors in the reinstatement of cocaine-seeking behavior. The goal of these experiments was to assess the role of muscarinic acetylcholine receptors in the nucleus accumbens core and shell in cocaine and sucrose priming-induced reinstatement. Rats were initially trained to self-administer cocaine or sucrose on a fixed-ratio schedule of reinforcement. Lever-pressing behavior was then extinguished and followed by a subsequent reinstatement phase during which operant responding was induced by either a systemic injection of cocaine in cocaine-experienced rats or non-contingent delivery of sucrose pellets in subjects with a history of sucrose self-administration. Results indicated that systemic administration of the muscarinic acetylcholine receptor antagonist scopolamine (5.0 mg/kg, i.p.) dose-dependently attenuated cocaine, but not sucrose, reinstatement. Furthermore, administration of scopolamine (36.0 μg) directly into the nucleus accumbens shell or core attenuated cocaine-priming induced reinstatement. In contrast, infusion of scopolamine (36.0 μg) directly into the accumbens core, but not shell, attenuated sucrose reinstatement, which suggests that muscarinic acetylcholine receptors in these two subregions of the nucleus accumbens have differential roles in sucrose seeking. Taken together, these results indicate that cocaine-priming induced reinstatement is mediated, in part, by increased signaling through muscarinic acetylcholine receptors in the shell subregion of the nucleus accumbens. Muscarinic acetylcholine receptors in the core of the accumbens, in contrast, appear to play a more general (i.e. not cocaine specific) role in motivated behaviors. PMID:21034738

  1. Application of PMF and CMB receptor models for the evaluation of the contribution of a large coal-fired power plant to PM10 concentrations.

    PubMed

    Contini, Daniele; Cesari, Daniela; Conte, Marianna; Donateo, Antonio

    2016-08-01

    The evaluation of the contribution of coal-fired thermo-electrical power plants to particulate matter (PM) is important for environmental management, for evaluation of health risks, and for its potential influence on climate. The application of receptor models, based on chemical composition of PM, is not straightforward because the chemical profile of this source is loaded with Si and Al and it is collinear with the profile of crustal particles. In this work, a new methodology, based on Positive Matrix Factorization (PMF) receptor model and Si/Al diagnostic ratio, specifically developed to discriminate the coal-fired power plant contribution from the crustal contribution is discussed. The methodology was applied to daily PM10 samples collected in central Italy in proximity of a large coal-fired power plant. Samples were simultaneously collected at three sites between 2.8 and 5.8km from the power plant: an urban site, an urban background site, and a rural site. Chemical characterization included OC/EC concentrations, by thermo-optical method, ions concentrations (NH4(+), Ca(2+), Mg(2+), Na(+), K(+), Mg(2+), SO4(2-), NO3(-), Cl(-)), by high performances ion chromatography, and metals concentrations (Si, Al, Ti, V, Mn, Fe, Ni, Cu, Zn, Br), by Energy dispersive X-ray Fluorescence (ED-XRF). Results showed an average primary contribution of the power plant of 2% (±1%) in the area studied, with limited differences between the sites. Robustness of the methodology was tested inter-comparing the results with two independent evaluations: the first obtained using the Chemical Mass Balance (CMB) receptor model and the second correlating the Si-Al factor/source contribution of PMF with wind directions and Calpuff/Calmet dispersion model results. The contribution of the power plant to secondary ammonium sulphate was investigated using an approach that integrates dispersion model results and the receptor models (PMF and CMB), a sulphate contribution of 1.5% of PM10 (±0.3%) as

  2. Scavenger receptor function of mouse FcγRIII contributes to progression of atherosclerosis in apoE hyperlipidemic mice1

    PubMed Central

    Zhu, Xinmei; Ng, Hang Pong; Lai, Yen-Chun; Craigo, Jodi K.; Nagilla, Pruthvi S.; Raghani, Pooja; Nagarajan, Shanmugam

    2014-01-01

    Recent studies showed loss of CD36 or scavenger receptor-AI/II (SR-A) does not ameliorate atherosclerosis in hyperlipidemic mouse model, suggesting receptors other than CD36 and SR-A may also contribute to atherosclerosis. In this report, we show that apoE-CD16 double knockout mice (apoE-CD16 DKO) have reduced atherosclerotic lesions compared with apoE KO mice. In vivo and in vitro foam cells analyses showed apoE-CD16 DKO macrophages accumulated less neutral lipids. Reduced foam cell formation in apoE-CD16 DKO mice is not due to change in expression of CD36, SR-A and LOX-1. This led to a hypothesis that CD16 may have scavenger receptor activity. We presented evidence that a soluble form of recombinant mouse CD16 (sCD16) bound to malondialdehyde-modified low-density lipoprotein (MDALDL), and this binding is blocked by molar excess of MDA-BSA and anti-MDA mAbs, suggesting CD16 specifically recognizes MDA epitopes. Interestingly, sCD16 inhibited MDALDL binding to macrophage cell line as well as sCD36, sSR-A and sLOX-1, indicating CD16 can cross-block MDALDL binding to other scavenger receptors. Anti-CD16 mAb inhibited IC binding to sCD16, while partially inhibited MDALDL binding to sCD16, suggesting MDALDL binding site may be in close proximity to the IC binding site in CD16. Loss of CD16 expression resulted in reduced levels of MDALDL induced pro-inflammatory cytokine expression. Finally, CD16 deficient macrophages showed reduced MDALDL-induced Syk phosphorylation. Collectively our findings suggest scavenger receptor activity of CD16 may in part contribute to the progression of atherosclerosis. PMID:25038257

  3. Function and structure in social brain regions can link oxytocin-receptor genes with autistic social behavior.

    PubMed

    Yamasue, Hidenori

    2013-02-01

    Difficulties in appropriate social and communicative behaviors are the most prevalent and core symptoms of autism spectrum disorders (ASDs). Although recent intensive research has focused on the neurobiological background of these difficulties, many aspects of them were not yet elucidated. Recent studies have employed multimodal magnetic resonance imaging (MRI) indices as intermediate phenotypes of this behavioral phenotype to link candidate genes with the autistic social difficulty. As MRI indices, functional MRI (fMRI), structural MRI, and MR-spectroscopy have been examined in subjects with autism spectrum disorders. As candidate genes, this mini-review has much interest in oxytocin-receptor genes (OXTR), since recent studies have repeatedly reported their associations with normal variations in social cognition and behavior as well as with their extremes, autistic social dysfunction. Through previous increasing studies, medial prefrontal cortex, hypothalamus and amygdala have repeatedly been revealed as neural correlates of autistic social behavior by MRI multimodalities and their relationship to OXTR. For further development of this research area, this mini-review integrates recent accumulating evidence about human behavioral and neural correlates of OXTR.

  4. Association Between Oxytocin Receptor Genotype, Maternal Care, and Eating Disorder Behaviours in a Community Sample of Women.

    PubMed

    Micali, Nadia; Crous-Bou, Marta; Treasure, Janet; Lawson, Elizabeth A

    2017-01-01

    This study aimed to investigate associations between oxytocin receptor gene (OXT-R) polymorphisms (rs53576 and rs2254298), their interaction with maternal care (GxE), and ED behaviours in a community sample. We studied 3698 women from the Avon Longitudinal Study of Parents and Children (ALSPAC) who participated in a two-phase prevalence study of lifetime ED and had genotype data. The GG rs53576 genotype was associated with binge eating and purging, and the rs2254298 AG/AA genotype with restrictive eating lifetime. In addition, the rs2254298 AG/AA genotype interacted with poor maternal care to increase the odds of binge eating and purging (odds ratio = 4.40 (95% confidence intervals: 1.11-17.4)). This study replicates previous findings of an association between OXT-R polymorphisms and ED, and it is the first to show an interaction between OXT-R genotype and poor maternal care. As such, these findings highlight the important role of oxytocin in understanding the pathophysiology of ED. © 2016 The Authors European Eating Disorders Review published by Eating Disorders Association and John Wiley & Sons Ltd.

  5. Ca2+ imaging of mouse neocortical interneurone dendrites: Contribution of Ca2+-permeable AMPA and NMDA receptors to subthreshold Ca2+dynamics

    PubMed Central

    Goldberg, Jesse H; Yuste, Rafael; Tamas, Gabor

    2003-01-01

    In this second study, we have combined two-photon calcium imaging with whole-cell recording and anatomic reconstructions to directly characterize synaptically evoked calcium signals in three types of mouse V1 supragranular interneurones: parvalbumin-positive fast spikers (FS), calretinin-positive irregular spikers (IS), and adapting cells (AD). We observed that subthreshold synaptic activation evoked calcium signals locally restricted to individual dendritic compartments. These signals were mediated by NMDA receptors (NMDARs) in AD and IS cells, whereas in FS cells, calcium-permeable AMPA receptors (CP-AMPARs) provided an additional and kinetically distinct influx. Furthermore, even a single, subthreshold synaptic activation evoked a larger dendritic calcium influx than backpropagating action potentials. Our results demonstrate that NMDARs dominate subthreshold calcium dynamics in interneurones and reveal the functional contribution of CP-AMPARs to a specific subclass of cortical interneurone. These data highlight different strategies in dendritic signal processing by distinct classes of interneurones. PMID:12844507

  6. Oxidative stress contributes to the enhanced expression of Gqα/PLCβ1 proteins and hypertrophy of VSMC from SHR: role of growth factor receptor transactivation.

    PubMed

    Atef, Mohammed Emehdi; Anand-Srivastava, Madhu B

    2016-03-01

    We showed previously that vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHRs) exhibit overexpression of Gqα/PLCβ1 proteins, which contribute to increased protein synthesis through the activation of MAP kinase signaling. Because oxidative stress has been shown to be increased in hypertension, the present study was undertaken to examine the role of oxidative stress and underlying mechanisms in enhanced expression of Gqα/PLCβ1 proteins and VSMC hypertrophy. Protein expression was determined by Western blotting, whereas protein synthesis and cell volume, markers for VSMC hypertrophy, were determined by [(3)H]-leucine incorporation and three-dimensional confocal imaging, respectively. The increased expression of Gqα/PLCβ1 proteins, increased protein synthesis, and augmented cell volume exhibited by VSMCs from SHRs were significantly attenuated by antioxidants N-acetyl-cysteine (NAC), a scavenger of superoxide anion, DPI, an inhibitor of NAD(P)H oxidase. In addition, PP2, AG1024, AG1478, and AG1295, inhibitors of c-Src, insulin-like growth factor receptor (IGFR), epidermal growth factor receptor (EGFR), and platelet-derived growth factor receptor (PDGFR), respectively, also attenuated the enhanced expression of Gqα/PLCβ1 proteins and enhanced protein synthesis in VSMCs from SHRs toward control levels. Furthermore, the levels of IGF-1R and EGFR proteins and not of PDGFR were also enhanced in VSMCs from SHRs, which were attenuated significantly by NAC, DPI, and PP2. In addition, NAC, DPI, and PP2 also attenuated the enhanced phosphorylation of IGF-1R, PDGFR, EGFR, c-Src, and EKR1/2 in VSMCs from SHRs. These data suggest that enhanced oxidative stress in VSMCs from SHRs activates c-Src, which through the transactivation of growth factor receptors and MAPK signaling contributes to enhanced expression of Gqα/PLCβ1 proteins and resultant VSMC hypertrophy.

  7. PYR/RCAR receptors contribute to ozone-, reduced air humidity-, darkness-, and CO2-induced stomatal regulation.

    PubMed

    Merilo, Ebe; Laanemets, Kristiina; Hu, Honghong; Xue, Shaowu; Jakobson, Liina; Tulva, Ingmar; Gonzalez-Guzman, Miguel; Rodriguez, Pedro L; Schroeder, Julian I; Broschè, Mikael; Kollist, Hannes

    2013-07-01

    Rapid stomatal closure induced by changes in the environment, such as elevation of CO2, reduction of air humidity, darkness, and pulses of the air pollutant ozone (O3), involves the SLOW ANION CHANNEL1 (SLAC1). SLAC1 is activated by OPEN STOMATA1 (OST1) and Ca(2+)-dependent protein kinases. OST1 activation is controlled through abscisic acid (ABA)-induced inhibition of type 2 protein phosphatases (PP2C) by PYRABACTIN RESISTANCE/REGULATORY COMPONENTS OF ABA RECEPTOR (PYR/RCAR) receptor proteins. To address the role of signaling through PYR/RCARs for whole-plant steady-state stomatal conductance and stomatal closure induced by environmental factors, we used a set of Arabidopsis (Arabidopsis thaliana) mutants defective in ABA metabolism/signaling. The stomatal conductance values varied severalfold among the studied mutants, indicating that basal ABA signaling through PYR/RCAR receptors plays a fundamental role in controlling whole-plant water loss through stomata. PYR/RCAR-dependent inhibition of PP2Cs was clearly required for rapid stomatal regulation in response to darkness, reduced air humidity, and O3. Furthermore, PYR/RCAR proteins seem to function in a dose-dependent manner, and there is a functional diversity among them. Although a rapid stomatal response to elevated CO2 was evident in all but slac1 and ost1 mutants, the bicarbonate-induced activation of S-type anion channels was reduced in the dominant active PP2C mutants abi1-1 and abi2-1. Further experiments with a wider range of CO2 concentrations and analyses of stomatal response kinetics suggested that the ABA signalosome partially affects the CO2-induced stomatal response. Thus, we show that PYR/RCAR receptors play an important role for the whole-plant stomatal adjustments and responses to low humidity, darkness, and O3 and are involved in responses to elevated CO2.

  8. Differential Contribution of the Aryl-Hydrocarbon Receptor and Toll-Like Receptor Pathways to IL-8 Expression in Normal and Cystic Fibrosis Airway Epithelial Cells Exposed to Pseudomonas aeruginosa

    PubMed Central

    Roussel, Lucie; LaFayette, Shantelle; Nguyen, Dao; Baglole, Carolyn J.; Rousseau, Simon

    2016-01-01

    Pseudomonas aeruginosa are gram-negative bacteria that frequently infect the lungs of cystic fibrosis (CF) patients. This bacterium is highly responsive to changes in its environment, resulting in the expression of a diverse array of genes that may contribute to the host inflammatory response. P. aeruginosa is well-known to induce neutrophilic inflammation via the activation of Toll-Like Receptors (TLRs). Recently, it was shown that pyocyanin, a phenazine produced by P. aeruginosa, binds to the aryl hydrocarbon receptor (AhR), leading to neutrophilic inflammation as part of the host defense response. In this study, we have investigated the contribution of the TLR and AhR signaling pathways to the expression of the neutrophil chemoattractant IL-8 in response to P. aeruginosa diffusible material. Although both pathways are involved in IL-8 synthesis, the AhR played a greater role when planktonic P. aeruginosa was grown in a media favoring phenazine synthesis. However, when P. aeruginosa was grown in a media that mimics the nutritional composition of CF sputa, both pathways contributed similarly to IL-8 synthesis. Finally, when P. aeruginosa was grown as a biofilm, the TLR pathway did not contribute to biofilm-driven IL-8 synthesis and AhR was found to only partially contribute to IL-8 synthesis, suggesting the contribution of another unknown signaling pathway. Therefore, the interaction between P. aeruginosa and airway epithelial cells is very dynamic, and sensor engagement is variable according to the adaptation of P. aeruginosa to the CF lung environment. PMID:28066767

  9. Differential Contribution of the Aryl-Hydrocarbon Receptor and Toll-Like Receptor Pathways to IL-8 Expression in Normal and Cystic Fibrosis Airway Epithelial Cells Exposed to Pseudomonas aeruginosa.

    PubMed

    Roussel, Lucie; LaFayette, Shantelle; Nguyen, Dao; Baglole, Carolyn J; Rousseau, Simon

    2016-01-01

    Pseudomonas aeruginosa are gram-negative bacteria that frequently infect the lungs of cystic fibrosis (CF) patients. This bacterium is highly responsive to changes in its environment, resulting in the expression of a diverse array of genes that may contribute to the host inflammatory response. P. aeruginosa is well-known to induce neutrophilic inflammation via the activation of Toll-Like Receptors (TLRs). Recently, it was shown that pyocyanin, a phenazine produced by P. aeruginosa, binds to the aryl hydrocarbon receptor (AhR), leading to neutrophilic inflammation as part of the host defense response. In this study, we have investigated the contribution of the TLR and AhR signaling pathways to the expression of the neutrophil chemoattractant IL-8 in response to P. aeruginosa diffusible material. Although both pathways are involved in IL-8 synthesis, the AhR played a greater role when planktonic P. aeruginosa was grown in a media favoring phenazine synthesis. However, when P. aeruginosa was grown in a media that mimics the nutritional composition of CF sputa, both pathways contributed similarly to IL-8 synthesis. Finally, when P. aeruginosa was grown as a biofilm, the TLR pathway did not contribute to biofilm-driven IL-8 synthesis and AhR was found to only partially contribute to IL-8 synthesis, suggesting the contribution of another unknown signaling pathway. Therefore, the interaction between P. aeruginosa and airway epithelial cells is very dynamic, and sensor engagement is variable according to the adaptation of P. aeruginosa to the CF lung environment.

  10. Signal regulatory protein-α interacts with the insulin receptor contributing to muscle wasting in chronic kidney disease.

    PubMed

    Thomas, Sandhya S; Dong, Yanjun; Zhang, Liping; Mitch, William E

    2013-08-01

    Insulin resistance from chronic kidney disease (CKD) stimulates muscle protein wasting but mechanisms causing this resistance are controversial. To help resolve this, we used microarray analyses to identify initiators of insulin resistance in the muscles of mice with CKD, glucose intolerance, and insulin resistance. CKD raised mRNAs of inflammatory cytokines in muscles and there was a 5.2-fold increase in signal regulatory protein-α (SIRP-α), a transmembrane glycoprotein principally present in muscle membranes. By immunoprecipitation we found it interacts with the insulin receptor and insulin receptor substrate-1 (IRS-1). Treatment of myotubes with a mixture of inflammatory cytokines showed that SIRP-α expression was increased by a NF-κB-dependent pathway. Blockade of NF-κB using a small-molecule chemical inhibitor or a dominant-negative IKKβ reduced cytokine-induced SIRP-α expression. The overexpression of SIRP-α in myotubes impaired insulin signaling and raised proteolysis while SIRP-α knockdown with siRNAs in skeletal muscle cells increased tyrosine phosphorylation of the insulin receptor and IRS-1 despite inclusion of cytokines. This led to increased p-Akt and suppression of protein degradation. Thus, SIRP-α is part of a novel mechanism for inflammation-mediated insulin resistance in muscle. In catabolic conditions with impaired insulin signaling, targeting SIRP-α may improve insulin sensitivity and prevent muscle atrophy.

  11. Estrogen receptor alpha gene ( ESR1) polymorphism can contribute to clinical findings in systemic lupus erythematosus patients.

    PubMed

    Drehmer, M N; Andrade, D; Pereira, I A; Marrero, A R; Muniz, Y C N; de Souza, I R; Löfgren, S E

    2017-03-01

    Background Estrogens have a modulatory effect on several immune responses, many of which are correlated to autoimmune diseases. Estrogens act through binding to their receptors, and an overexpression of these receptors has been identified in patients with different autoimmune diseases. Here we analyzed the association of a putative functional genetic variant in the main estrogen receptor (ERα) gene ( ESR1), and the susceptibility to clinical findings and severity of SLE. Methods A total of 426 individuals (266 healthy controls and 160 SLE patients) were genotyped for the polymorphism rs2234693 in the ESR1 gene. Allele and genotype frequencies were calculated and analyzed between cases and controls using Unphased software. Results The SNP rs2234693 was not associated with SLE per se but the minor allele rs2234693-C was correlated with the presence of nephritis and discoid skin rash. On the other hand, the rs2234693-CC genotype was correlated with the absence of arthritis as well as anti-ANA and anti-RNP autoantibodies. The comprehensive clinical analysis of these patients revealed a more severe status of the disease, characterized by a younger age of onset and higher number of organs involved when compared to European populations. Conclusions Minor allele rs2234693-C was associated with renal and cutaneous involvement, as well as the absence of arthritis, anti-ANA and anti-RNP autoantibodies.

  12. Spinal astrocytic activation contributes to both induction and maintenance of pituitary adenylate cyclase-activating polypeptide type 1 receptor-induced long-lasting mechanical allodynia in mice

    PubMed Central

    Yokai, Masafumi; Miyata, Atsuro

    2016-01-01

    Background Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors are present in the spinal dorsal horn and dorsal root ganglia, suggesting an important role of PACAP–PACAP receptors signaling system in the modulation of spinal nociceptive transmission. We have previously reported that a single intrathecal injection of PACAP or a PACAP specific (PAC1) receptor selective agonist, maxadilan, in mice induced dose-dependent aversive behaviors, which lasted more than 30 min, and suggested that the maintenance of the nociceptive behaviors was associated with the spinal astrocytic activation. Results We found that a single intrathecal administration of PACAP or maxadilan also produced long-lasting hind paw mechanical allodynia, which persisted at least 84 days without affecting thermal nociceptive threshold. In contrast, intrathecal application of vasoactive intestinal polypeptide did not change mechanical threshold, and substance P, calcitonin gene-related peptide, or N-methyl-D-aspartate induced only transient mechanical allodynia, which disappeared within 21 days. Western blot and immunohistochemical analyses with an astrocytic marker, glial fibrillary acidic protein, revealed that the spinal PAC1 receptor stimulation caused sustained astrocytic activation, which also lasted more than 84 days. Intrathecal co-administration of L-α-aminoadipate, an astroglial toxin, with PACAP or maxadilan almost completely prevented the induction of the mechanical allodynia. Furthermore, intrathecal treatment of L-α-aminoadipate at 84 days after the PAC1 stimulation transiently reversed the mechanical allodynia accompanied by the reduction of glial fibrillary acidic protein expression level. Conclusion Our data suggest that spinal astrocytic activation triggered by the PAC1 receptor stimulation contributes to both induction and maintenance of the long-term mechanical allodynia. PMID:27175011

  13. Activation of cannabinoid CB1 receptor contributes to suppression of spinal nociceptive transmission and inhibition of mechanical hypersensitivity by Aβ-fiber stimulation.

    PubMed

    Yang, Fei; Xu, Qian; Shu, Bin; Tiwari, Vinod; He, Shao-Qiu; Vera-Portocarrero, Louis P; Dong, Xinzhong; Linderoth, Bengt; Raja, Srinivasa N; Wang, Yun; Guan, Yun

    2016-11-01

    Activation of Aβ-fibers is an intrinsic feature of spinal cord stimulation (SCS) pain therapy. Cannabinoid receptor type 1 (CB1) is important to neuronal plasticity and pain modulation, but its role in SCS-induced pain inhibition remains unclear. In this study, we showed that CB1 receptors are expressed in both excitatory and inhibitory interneurons in substantia gelatinosa (SG). Patch-clamp recording of the evoked excitatory postsynaptic currents (eEPSCs) in mice after spinal nerve ligation (SNL) showed that electrical stimulation of Aβ-fibers (Aβ-ES) using clinical SCS-like parameters (50 Hz, 0.2 millisecond, 10 μA) induced prolonged depression of eEPSCs to C-fiber inputs in SG neurons. Pretreatment with CB1 receptor antagonist AM251 (2 μM) reduced the inhibition of C-eEPSCs by Aβ-ES in both excitatory and inhibitory SG neurons. We further determined the net effect of Aβ-ES on spinal nociceptive transmission in vivo by recording spinal local field potential in SNL rats. Epidural SCS (50 Hz, Aβ-plateau, 5 minutes) attenuated C-fiber-evoked local field potential. This effect of SCS was partially reduced by spinal topical application of AM251 (25 μg, 50 μL), but not CB2 receptor antagonist AM630 (100 μg). Finally, intrathecal pretreatment with AM251 (50 μg, 15 μL) in SNL rats blocked the inhibition of behavioral mechanical hypersensitivity by SCS (50 Hz, 0.2 millisecond; 80% of motor threshold, 60 minutes). Our findings suggest that activation of spinal CB1 receptors may contribute to synaptic depression to high-threshold afferent inputs in SG neurons after Aβ-ES and may be involved in SCS-induced inhibition of spinal nociceptive transmission after nerve injury.

  14. Renal (pro)renin receptor contributes to development of diabetic kidney disease through transforming growth factor-β1-connective tissue growth factor signalling cascade.

    PubMed

    Huang, Jiqian; Matavelli, Luis C; Siragy, Helmy M

    2011-04-01

    1. Transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) are expressed in renal glomeruli, and contribute to the development of diabetic nephropathy. Recently, we showed that (pro)renin receptor (PRR) is upregulated in the kidneys of the streptozocin (STZ)-induced diabetes rat model. We hypothesized that in the presence of hyperglycaemia, increased renal PRR expression contributes to enhanced TGF-β1-CTGF signalling activity, leading to the development of diabetic kidney disease. 2. In vivo and in vitro studies were carried out in Sprague-Dawley rats and rat mesangial cells (RMC). PRR blockade was achieved in vivo by treating STZ induced diabetes rats with the handle region peptide (HRP) of prorenin and in vitro by HRP or PRR siRNA in RMC. Angiotensin AT1 receptor blockade was achieved by valsartan treatment. 3. Results showed that expression of PRR, TGF-β1 and CTGF were upregulated in diabetic kidneys and RMC exposed to high glucose. Glucose exposure also induced PRR phosphorylation, a process that was inhibited by HRP, valsartan or PRR siRNA. HRP and valsartan significantly attenuated renal TGF-β1 and CTGF expression in diabetic animals and high glucose treated RMC. Similar results were observed in high glucose exposed RMC in response to PRR siRNA. TGF-β receptor blockade decreased CTGF expression in RMC. Combined administration of valsartan and PRR siRNA showed further reduction of TGF-β1 and CTGF expression in RMC. 4. In conclusion, PRR contributes to kidney disease in diabetes through an enhanced TGF-β1-CTGF signalling cascade.

  15. Contribution of nicotinic receptors to the function of synapses in the central nervous system: the action of choline as a selective agonist of alpha 7 receptors.

    PubMed

    Albuquerque, E X; Pereira, E F; Braga, M F; Alkondon, M

    1998-01-01

    The alpha 7-nicotinic receptor (nAChR)-selective agonist choline and nAChR-subtype-selective antagonists led to the discovery that activation of both alpha 7 and alpha 4 beta 2 nAChRs located in CA1 interneurons in slices taken from the rat hippocampus facilitates the tetrodotoxin (TTX)-sensitive release of gamma-aminobutyric acid (GABA). Experiments carried out in cultured hippocampal neurons not only confirmed that preterminal alpha 7 and alpha 4 beta 2 nAChRs modulate the TTX-sensitive release of GABA, but also demonstrated that evoked release of GABA is reduced by rapid exposure of the neurons to acetylcholine (ACh, 10 microM-1 mM) in the presence of the muscarinic receptor antagonist atropine (1 microM). This effect of ACh, which is fully reversible and concentration-dependent, is partially blocked by superfusion of the cultured neurons with external solution containing either the alpha 7-nAChR-selective antagonist methyllycaconitine (MLA, 1 nM) or the alpha 4 beta 2-nAChR-selective antagonist dihydro-beta-erythroidine (DH beta E, 100 nM). A complete blockade of ACh-induced reduction of evoked release of GABA was achieved only when the neurons were perfused with external solution containing both MLA and DH beta E, suggesting that activation of both alpha 7 and alpha 4 beta 2 nAChRs modulates the evoked release of GABA from hippocampal neurons. Such mechanisms may account for the apparent involvement of nAChRs in the psychological effects of tobacco smoking, in brain disorders (e.g., schizophrenia and epilepsy), and in physiological processes, including cognition and nociception.

  16. Structural characteristics of anabolic androgenic steroids contributing to binding to the androgen receptor and to their anabolic and androgenic activities. Applied modifications in the steroidal structure.

    PubMed

    Fragkaki, A G; Angelis, Y S; Koupparis, M; Tsantili-Kakoulidou, A; Kokotos, G; Georgakopoulos, C

    2009-02-01

    Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone introduced for therapeutic purposes providing enhanced anabolic potency with reduced androgenic effects. Androgens mediate their action through their binding to the androgen receptor (AR) which is mainly expressed in androgen target tissues, such as the prostate, skeletal muscle, liver and central nervous system. This paper reviews some of the wide spectrum of testosterone and synthetic AAS structure modifications related to the intended enhancement in anabolic activity. The structural features of steroids necessary for effective binding to the AR and those which contribute to the stipulation of the androgenic and anabolic activities are also presented.

  17. Kinin B(1) and B(2) receptors contribute to orofacial heat hyperalgesia induced by infraorbital nerve constriction injury in mice and rats.

    PubMed

    Luiz, Ana Paula; Schroeder, Samilla Driessen; Chichorro, Juliana Geremias; Calixto, João Batista; Zampronio, Aleksander Roberto; Rae, Giles Alexander

    2010-04-01

    Mechanisms coupled to kinin B(1) and B(2) receptors have been implicated in sensory changes associated to various models of neuropathy. The current study aimed to investigate if kinins also participate in orofacial thermal hyperalgesia induced by constriction of the infraorbital nerve (CION), a model of trigeminal neuropathic pain which displays persistent hypersensitivity to orofacial sensory stimulation, in rats and mice. Male Swiss mice (30-35g) or Wistar rats (200-250g; n=6-10 per group in both cases) underwent CION or sham surgery and were submitted repeatedly to application of heat ( approximately 50 degrees C) to the ipsilateral or contralateral snout, delivered by a heat source placed 1cm from the vibrissal pad. Decreases in latency to display head withdrawal or vigorous snout flicking were considered indicative of heat hyperalgesia. CION caused long-lasting heat hyperalgesia which started on Day 2 after surgery in both species and lasted up to Day 17 in mice and Day 10 in rats. Administration of DALBK or HOE-140 (peptidic B(1) and B(2) receptor antagonists, respectively; each at 3nmol in 10microl) onto the exposed infraorbital nerve of mice at the moment of surgery delayed the development of the thermal hyperalgesia. Systemic treatment on Day 5 (mice) or Day 4 (rats) with Des-Arg(9), Leu(8)-Bradykinin (DALBK, B(1) receptor antagonist, 0.1-1micromol/kg, i.p.) or HOE-140 (B(2) receptor antagonist, 0.001-1micromol/kg, i.p.) transiently reduced heat hyperalgesia in both species. Due to the peptidic nature of DALBK and HOE-140, it is likely that their effects reported herein resulted from blockade of peripheral kinin receptors. Thus, mechanisms operated by kinin B(1) and B(2) receptors, contribute to orofacial heat hyperalgesia induced by CION in both mice and rats. Perhaps kinin B(1) and B(2) receptor antagonists might constitute effective preventive and curative treatments for orofacial thermal hyperalgesia induced by nerve injury.

  18. Anticancer immunotherapy by CTLA-4 blockade: obligatory contribution of IL-2 receptors and negative prognostic impact of soluble CD25

    PubMed Central

    Hannani, Dalil; Vétizou, Marie; Enot, David; Rusakiewicz, Sylvie; Chaput, Nathalie; Klatzmann, David; Desbois, Melanie; Jacquelot, Nicolas; Vimond, Nadège; Chouaib, Salem; Mateus, Christine; Allison, James P; Ribas, Antoni; Wolchok, Jedd D; Yuan, Jianda; Wong, Philip; Postow, Michael; Mackiewicz, Andrzej; Mackiewicz, Jacek; Schadendorff, Dirk; Jaeger, Dirk; Korman, Alan J; Bahjat, Keith; Maio, Michele; Calabro, Luana; Teng, Michele WL; Smyth, Mark J; Eggermont, Alexander; Robert, Caroline; Kroemer, Guido; Zitvogel, Laurence

    2015-01-01

    The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab induces immune-mediated long-term control of metastatic melanoma in a fraction of patients. Although ipilimumab undoubtedly exerts its therapeutic effects via immunostimulation, thus far clinically useful, immunologically relevant biomarkers that predict treatment efficiency have been elusive. Here, we show that neutralization of IL-2 or blocking the α and β subunits of the IL-2 receptor (CD25 and CD122, respectively) abolished the antitumor effects and the accompanying improvement of the ratio of intratumoral T effector versus regulatory cells (Tregs), which were otherwise induced by CTLA-4 blockade in preclinical mouse models. CTLA-4 blockade led to the reduction of a suppressive CD4+ T cell subset expressing Lag3, ICOS, IL-10 and Egr2 with a concomitant rise in IL-2-producing effector cells that lost FoxP3 expression and accumulated in regressing tumors. While recombinant IL-2 improved the therapeutic efficacy of CTLA-4 blockade, the decoy IL-2 receptor α (IL-2Rα, sCD25) inhibited the anticancer effects of CTLA-4 blockade. In 262 metastatic melanoma patients receiving ipilimumab, baseline serum concentrations of sCD25 represented an independent indicator of overall survival, with high levels predicting resistance to therapy. Altogether, these results unravel a role for IL-2 and IL-2 receptors in the anticancer activity of CTLA-4 blockade. Importantly, our study provides the first immunologically relevant biomarker, namely elevated serum sCD25, that predicts resistance to CTLA-4 blockade in patients with melanoma. PMID:25582080

  19. TAK1 contributes to the enhanced responsiveness of LTB(4)-treated neutrophils to Toll-like receptor ligands.

    PubMed

    Gaudreault, Éric; Paquet-Bouchard, Carine; Fiola, Stéphanie; Le Bel, Manon; Lacerte, Patricia; Shio, Marina Tiemi; Olivier, Martin; Gosselin, Jean

    2012-11-01

    Pattern-recognition receptors such as Toll-like receptors (TLRs) are essential sensors implicated in the early and efficient innate immune response against pathogens. We have previously demonstrated that leukotriene B(4)(LTB(4)) has the capacity to enhance leukocyte responses to TLR9 ligands and to control viral infection. In this report, we provide evidence that LTB(4) treatment of human neutrophils leads to a potentiation in proinflammatory cytokine secretion induced by various myeloid differentiation factor 88-dependent TLR agonists. LTB(4) failed to enhance TLR mRNA levels as well as expression of TLR2 and TLR4 receptors, suggesting that LTB(4) acts through intracellular mechanism(s) to potentiate neutrophil responses to TLR ligands. We found that while IRAK can be activated by LTB(4), this process is dispensable to LTB(4) to potentiate neutrophil responses to TLR ligands since pretreatment of neutrophils with IRAK1/4 inhibitor did not affect its potentiating effects. However, our data clearly show that LTB(4) treatment of neutrophils led to the phosphorylation of downstream signaling molecules, TAK1 and p38, a process found essential to observe an increased secretion of cytokines by neutrophils activated with TLR ligands. Pretreatment of neutrophils with TAK1 or p38 kinase inhibitors strongly repressed the effect of LTB(4) on cytokine synthesis by neutrophils stimulated with LTA, LPS or CpG. The same pattern was observed in agonist-treated human embryonic kidney 293 cells transfected with TAK1-targeting siRNA where secretion of IL-8 was significantly reduced to basal levels. These results indicate that TAK1 and p38 kinases appear to be central in the 'priming effect' of LTB(4) on neutrophils to enhance response to TLR ligands.

  20. Contribution of melanin-concentrating hormone (MCH1) receptor to thermoregulation and sleep stabilization: evidence from MCH1 (-/-) mice.

    PubMed

    Ahnaou, A; Dautzenberg, F M; Huysmans, H; Steckler, T; Drinkenburg, W H I M

    2011-03-17

    Recent studies have explored the implication of melanin-concentrating hormone (MCH) in the process of vigilance states. The current experiments were carried out in mice lacking the MCH(1) receptor (-/-) and wild-type (WT) littermates, to assess the role of MCH(1) receptor in the regulation of sleep architecture, body temperature (BT) and locomotor activity (LMA) under normal condition and following a 1h restraint stress at lights onset. Under baseline conditions, MCH(1) (-/-) mice exhibited consistent changes in waking and sleeping time across the 24-h recording period. We found an increase in the amount of wakefulness (MCH(1) (-/-) 680.1 ± 15.3 min vs. WT, 601.9 ± 18.1, p<0.05) at the expense of total duration of non rapid eye movement (NREM) sleep (MCH(1) (-/-) 664.1 ± 13.9 min vs. WT 750.1 ± 18.5, p<0.05). Additionally, MCH(1) (-/-) mice had a higher mean basal body temperature (MCH(1) (-/-), 36.6 ± 0.1°C vs. WT, 36.0 ± 0.1°C, p<0.05), particularly during the light-resting period. Restraint stress resulted in an immediate increase in wakefulness with a concomitant reduction in NREM sleep and REM sleep in both genotypes, followed by a homeostatic rebound sleep. A concomitant long lasting increase in BT, independently of the behavioural state accompanied those changes in both genotypes. The elevated basal body temperature and reduction in NREM sleep time resulting from shorter NREM episode durations observed in MCH(1) (-/-) suggests that central MCH(1) receptor has a role in thermoregulation and presumably stabilization of NREM sleep.

  1. Lineage-Specific Expansion of Vomeronasal Type 2 Receptor-Like (OlfC) Genes in Cichlids May Contribute to Diversification of Amino Acid Detection Systems

    PubMed Central

    Nikaido, Masato; Suzuki, Hikoyu; Toyoda, Atsushi; Fujiyama, Asao; Hagino-Yamagishi, Kimiko; Kocher, Thomas D.; Carleton, Karen; Okada, Norihiro

    2013-01-01

    Fish use olfaction to sense a variety of nonvolatile chemical signals in water. However, the evolutionary importance of olfaction in species-rich cichlids is controversial. Here, we determined an almost complete sequence of the vomeronasal type 2 receptor-like (OlfC: putative amino acids receptor in teleosts) gene cluster using the bacterial artificial chromosome library of the Lake Victoria cichlid, Haplochromis chilotes. In the cluster region, we found 61 intact OlfC genes, which is the largest number of OlfC genes identified among the seven teleost fish investigated to date. Data mining of the Oreochromis niloticus (Nile tilapia) draft genome sequence, and genomic Southern hybridization analysis revealed that the ancestor of all modern cichlids had already developed almost the same OlfC gene repertoire, which was accomplished by lineage-specific gene expansions. Furthermore, comparison of receptor sequences showed that recently duplicated paralogs are more variable than orthologs of different species at particular sites that were predicted to be involved in amino acid selectivity. Thus, the increase of paralogs through gene expansion may lead to functional diversification in detection of amino acids. This study implies that cichlids have developed a potent capacity to detect a variety of amino acids (and their derivatives) through OlfCs, which may have contributed to the extraordinary diversity of their feeding habitats. PMID:23501830

  2. Expression of 5-HT3 receptors by extrinsic duodenal afferents contribute to intestinal inhibition of gastric emptying.

    PubMed

    Raybould, Helen E; Glatzle, Jorg; Robin, Carla; Meyer, James H; Phan, Thomas; Wong, Helen; Sternini, Catia

    2003-03-01

    Intestinal perfusion with carbohydrates inhibits gastric emptying via vagal and spinal capsaicin-sensitive afferent pathways. The aim of the present study was to determine the role of 1) 5-hydroxytryptamine (5-HT)(3) receptors (5-HT(3)R) in mediating glucose-induced inhibition of gastric emptying and 2) 5-HT(3)R expression in vagal and spinal afferents in innervating the duodenum. In awake rats fitted with gastric and duodenal cannulas, perfusion of the duodenum with glucose (50 and 100 mg) inhibited gastric emptying. Intestinal perfusion of mannitol inhibited gastric emptying only at the highest concentration (990 mosm/kgH(2)O). Pretreatment with the 5-HT(3)R antagonist tropisetron abolished both glucose- and mannitol-induced inhibition of gastric emptying. Retrograde labeling of visceral afferents by injection of dextran-conjugated Texas Red into the duodenal wall was used to identify extrinsic primary afferents. Immunoreactivity for 5-HT(3)R, visualized with an antibody directed to the COOH terminus of the rat 5-HT(3)R, was found in >80% of duodenal vagal and spinal afferents. These results show that duodenal extrinsic afferents express 5-HT(3)R and that the receptor mediates specific glucose-induced inhibition of gastric emptying. These findings support the hypothesis that enterochromaffin cells in the intestinal mucosa release 5-HT in response to glucose, which activates 5-HT(3)R on afferent nerve terminals to evoke reflex changes in gastric motility. The primary glucose sensors of the intestine may be mucosal enterochromaffin cells.

  3. Adenosine through the A2A adenosine receptor increases IL-1β in the brain contributing to anxiety

    PubMed Central

    Chiu, Gabriel S.; Darmody, Patrick T.; Walsh, John P.; Moon, Morgan L.; Kwakwa, Kristin A.; Bray, Julie K.; McCusker, Robert H.; Freund, Gregory G.

    2014-01-01

    Anxiety is one of the most commonly reported psychiatric conditions, but its pathogenesis is poorly understood. Ailments associated with activation of the innate immune system, however, are increasingly linked to anxiety disorders. In adult male mice, we found that adenosine doubled caspase-1 activity in brain by a pathway reliant on ATP-sensitive potassium (KATP) channels, protein kinase A (PKA) and the A2A adenosine receptor (AR). In addition, adenosine-dependent activation of caspase-1 increased interleukin (IL)-1β in the brain by two-fold. Peripheral administration of adenosine in wild-type (WT) mice led to a 2.3-fold increase in caspase-1 activity in the amygdala and to a 33% and 42% reduction in spontaneous locomotor activity and food intake, respectively, that were not observed in caspase-1 knockout (KO), IL-1 receptor type 1 (IL-1R1) KO and A2A AR KO mice or in mice administered a caspase-1 inhibitor centrally. Finally, adenosine administration increased anxiety-like behaviors in WT mice by 28% in the open field test and by 55% in the elevated zero-maze. Caspase-1 KO mice, IL-1R1 KO mice, A2A AR KO mice and WT mice treated with the KATP channel blocker, glyburide, were resistant to adenosine-induced anxiety-like behaviors. Thus, our results indicate that adenosine can act as an anxiogenic by activating caspase-1 and increasing IL-1β in the brain. PMID:24907587

  4. Loss of sorting nexin 27 contributes to excitatory synaptic dysfunction via modulation of glutamate receptor recycling in Down syndrome

    PubMed Central

    Wang, Xin; Zhao, Yingjun; Zhang, Xiaofei; Badie, Hedieh; Zhou, Ying; Mu, Yangling; Loo, Li Shen; Cai, Lei; Thompson, Robert C.; Yang, Bo; Chen, Yaomin; Johnson, Peter F.; Wu, Chengbiao; Bu, Guojun; Mobley, William C.; Zhang, Dongxian; Gage, Fred H.; Ranscht, Barbara; Zhang, Yun-wu; Lipton, Stuart A.; Hong, Wanjin; Xu, Huaxi

    2014-01-01

    Sorting nexin 27 (SNX27), a brain-enriched PDZ domain protein, regulates endocytic sorting and trafficking. Here, we show that Snx27−/− mice exhibit severe neuronal deficits in the hippocampus and cortex. While Snx27+/− mice exhibit grossly normal neuroanatomy, we find defects in synaptic function, learning and memory, and a reduction in ionotropic glutamate receptors (NMDARs and AMPARs). SNX27 interacts with these receptors through its PDZ domain, regulating their recycling to the plasma membrane. We demonstrate a concomitant reduction of SNX27 and C/EBPβ in Down syndrome brains and identify C/EBPβ as a transcription factor for SNX27. Down syndrome causes over-expression of miR-155, a chromosome 21-encoded microRNA that negatively regulates C/EBPβ, thereby reducing SNX27 and resulting in synaptic dysfunction. Up-regulating SNX27 in the hippocampus of Down syndrome mice rescues synaptic and cognitive deficits. Our identification of the role of SNX27 in synaptic function establishes a novel molecular mechanism of Down syndrome pathogenesis. PMID:23524343

  5. Association of a Common Oxytocin Receptor Gene Polymorphism with Self-Reported ‘Empathic Concern’ in a Large Population of Healthy Volunteers

    PubMed Central

    Reinders, Anette; Siffert, Doris; Stelmach, Patrick; Knop, Dietmar; Horn, Peter Alexander; Siffert, Winfried

    2016-01-01

    Background Previous research has linked genomic variations of the oxytocin receptor (OXTR) gene with individual differences in empathy. The impact of these variations on specific cognitive and emotional aspects of empathy, however, remains to be clarified. Methods We analysed associations of a common OXTR polymorphism (rs53576) with trait empathy in a sample of 421 blood donors (231 M, 190 F; age 18–74) using the Interpersonal Reactivity Index (IRI) as an established multidimensional self-report measure of empathy. Results Female sex was significantly associated with higher empathy scores in all IRI scales (p<0.001) with the exception of the cognitive perspective taking scale (p = 0.09). The overall trait empathy score was significantly associated with rs53576 (p = 0.01), with mean scores increasing from AA to GG genotypes. An analysis of the IRI subscores revealed that the polymorphism was especially associated with the emotional empathic concern scale (p = 0.02). Separate analysis of the male and female subgroup revealed a significant association of the polymorphism with female (p = 0.04), but not with male (p = 0.20) empathic concern. A comparison of effect sizes between the groups showed greater effects for women compared to men although effect size differences did not become significant in our sample. Conclusions Our findings suggest a significant association of the rs53576 OXTR gene polymorphism with trait empathy and especially with emotional aspects of empathy. This association is possibly weaker or absent in men compared to women. PMID:27467763

  6. GluN2B-Containg NMDA Receptors on Adult-Born Granule Cells Contribute to the Antidepressant Action of Fluoxetine

    PubMed Central

    Tannenholz, Lindsay; Hen, René; Kheirbek, Mazen A.

    2016-01-01

    Ablation of adult neurogenesis in mice has revealed that young adult-born granule cells (abGCs) are required for some of the behavioral responses to antidepressants (ADs), yet the mechanism by which abGCs contribute to AD action remains unknown. During their maturation process, these immature neurons exhibit unique properties that could underlie their ability to influence behavioral output. In particular, abGCs in the DG exhibit a period of heightened plasticity 4–6 weeks after birth that is mediated by GluN2B-expressing NMDA receptors. The functional contribution of this critical window to AD responsiveness is unclear. Here, we determined the behavioral and neurogenic responses to the AD fluoxetine (FLX) in mice lacking GluN2B-containing NMDA receptors in abGCs. We found that these mice exhibited an attenuated response to FLX in a neurogenesis-dependent behavioral assay of FLX action, while neurogenesis-independent behaviors were unaffected by GluN2B deletion. In addition, deletion of GluN2B attenuated FLX-induced increases in dendritic complexity of abGCs suggesting that the blunted behavioral efficacy of FLX may be caused by impaired differentiation of young abGCs. PMID:27303260

  7. Tyrosine phosphorylation of the N-Methyl-D-Aspartate receptor 2B subunit in spinal cord contributes to remifentanil-induced postoperative hyperalgesia: the preventive effect of ketamine

    PubMed Central

    2009-01-01

    Background Experimental and clinical studies showed that intraoperative infusionof remifentanil has been associated with postoperative hyperalgesia. Previous reports suggested that spinal N-methyl-D-aspartate (NMDA) receptors may contribute to the development and maintenance of opioid-induced hyperalgesia. In the present study, we used a rat model of postoperative pain to investigate the role of tyrosine phosphorylation of NMDA receptor 2B (NR2B) subunit in spinal cord in the postoperative hyperalgesia induced by remifentanil and the intervention of pretreatment with ketamine. Results Intraoperative infusion of remifentanil (0.04 mg/kg, subcutaneous) significantly enhanced mechanical allodynia and thermal hyperalgesia induced by the plantar incision during the postoperative period (each lasting between 2 h and 48 h), which was attenuated by pretreatment with ketamine (10 mg/kg, subcutaneous). Correlated with the pain behavior changes, immunocytochemical and western blotting experiments in our study revealed that there was a marked increase in NR2B phosphorylation at Tyr1472 in the superficial dorsal horn after intraoperative infusion of remifentanil, which was attenuated by pretreatment with ketamine. Conclusions This study provides direct evidence that tyrosine phosphorylation of the NR2B at Tyr1472 in spinal dosal horn contributes to postoperative hyperalgesia induced by remifentanil and supports the potential therapeutic value of ketamine for improving postoperative hyperalgesia induced by remifentanil. PMID:20042082

  8. Source Contribution Analysis of Surface Particulate Polycyclic Aromatic Hydrocarbon Concentrations in Northeastern Asia by Source-receptor Relationships

    SciTech Connect

    Inomata, Yayoi; Kajino, Mizuo; Sato, Keiichi; Ohara, Toshimasa; Kurokawa, Jun-Ichi; Ueda, Hiromasa; Tang, Ning; Hayakawa, Kazuichi; Ohizumi, Tsuyoshi; Akimoto, Hajime

    2013-11-01

    We analyzed the sourceereceptor relationships for particulate polycyclic aromatic hydrocarbon (PAH) concentrations in northeastern Asia using an aerosol chemical transport model. The model successfully simulated the observed concentrations. In Beijing (China) benzo[a]pyren (BaP) concentrations are due to emissions from its own domain. In Noto, Oki and Tsushima (Japan), transboundary transport from northern China (>40°N, 40-60%) and central China (30-40°N, 10-40%) largely influences BaP concentrations from winter to spring, whereas the relative contribution from central China is dominant (90%) in Hedo. In the summer, the contribution from Japanese domestic sources increases (40-80%) at the 4 sites. Contributions from Japan and Russia are additional source of BaP over the northwestern Pacific Ocean in summer. The contribution rates for the concentrations from each domain are different among PAH species depending on their particulate phase oxidation rates. Reaction with O3 on particulate surfaces may be an important component of the PAH oxidation processes.

  9. Macrophages and Fc-receptor interactions contribute to the antitumour activities of the anti-CD40 antibody SGN-40.

    PubMed

    Oflazoglu, E; Stone, I J; Brown, L; Gordon, K A; van Rooijen, N; Jonas, M; Law, C-L; Grewal, I S; Gerber, H-P

    2009-01-13

    SGN-40 is a therapeutic antibody targeting CD40, which induces potent anti-lymphoma activities via direct apoptotic signalling cells and by cell-mediated cytotoxicity. Here we show antibody-dependent cellular phagocytosis (ADCP) by macrophages to contribute significantly to the therapeutic activities and that the antitumour effects of SGN-40 depend on Fc interactions.

  10. Overexpression of farnesoid X receptor in small airways contributes to epithelial to mesenchymal transition and COX-2 expression in chronic obstructive pulmonary disease

    PubMed Central

    Chen, Bi; You, Wen-Jie; Xue, Shan; Qin, Hui; Zhao, Xu-Ji; Zhang, Miao; Liu, Xue-Qing; Zhu, Shu-Yang

    2016-01-01

    Background Epithelial-mesenchymal transition (EMT) and cyclooxygenase-2 (COX-2) contribute to airway remodelling and inflammation in chronic obstructive pulmonary disease (COPD). Recent data suggest that the farnesoid X receptor (FXR), a nuclear receptor traditionally considered as bile acid-activated receptor, is also expressed in non-classical bile acids target tissues with novel functions beyond regulating bile acid homeostasis. This study aimed to investigate the potential role of FXR in the development of COPD, as well as factors that affect FXR expression. Methods Expression of FXR, EMT biomarkers and COX-2 was examined by immunohistochemistry in lung tissues from non-smokers, smokers, and smokers with COPD. The role of FXR in TGF-β1-induced EMT and COX-2 expression in human bronchial epithelial (HBE) cells was evaluated in vitro. Factors regulating FXR expression were assessed in cultured HBE cells and a cigarette smoke-induced rat model of COPD. Results Expression of FXR, EMT markers and COX-2 was significantly elevated in small airway epithelium of COPD patients compared with controls. The staining scores of FXR in small airway epithelium were negatively related with FEV1% of predicted of smokers without and with COPD. FXR agonist GW4064 remarkably enhanced and FXR antagonist Z-Guggulsterone significantly inhibited EMT changes in TGF-β1-treated HBE cells. Both chenodeoxycholic acid (CDCA) and GW4064 increased COX-2 expression in HBE cells, whereas Z-Guggulsterone dramatically restrained CDCA-induced COX-2 expression. Finally, FXR expression is induced by IL-4 and IL-13 in HBE cells, as well as by cigarette smoke exposure in a rat model of COPD. Conclusions Overexpression of FXR in small airway may contribute to airway remodelling and inflammation in COPD by regulating EMT and COX-2 expression. PMID:28066584

  11. Contribution of conserved polar glutamine, asparagine and threonine residues and glycosylation to agonist action at human P2X1 receptors for ATP.

    PubMed

    Roberts, Jonathan A; Evans, Richard J

    2006-02-01

    The role of conserved polar glutamine, asparagine and threonine residues in the large extracellular loop, and glycosylation, to agonist action at human P2X1 receptors was tested by generating alanine substitution mutants. For the majority of mutants (Q56A, Q95A, T104A, T109A, Q112A, Q114A, T146A, N153A, T158A, N184A, N191A, N242A, N300A) alanine substitution had no effect on ATP potency. The mutants Q95A, Q112A, Q114A and T158A showed changes in efficacy for the partial agonists BzATP and Ap5A, suggesting that these polar residues may contribute to the gating of the channel. The mutants T186A, N204A and N290A had six-, three- and 60-fold decreases in ATP potency, respectively. For T186A and N290A, the partial agonists BzATP and Ap5A were no longer agonists but still bind to the receptor as shown by the ability to modulate the response to co-applied ATP. N153, N184 and N242 are glycosylated in the endoplasmic reticulum and N300 acquires complex glycosylation in the golgi. These results aid in refining a model for ATP binding at the P2X1 receptor where the residues F185T186, and the conserved triplet N290F291R292, are likely to play a role in ATP action at the receptor.

  12. The GABAB receptor agonist, baclofen, contributes to three distinct varieties of amnesia in the human brain - A detailed case report.

    PubMed

    Zeman, Adam; Hoefeijzers, Serge; Milton, Fraser; Dewar, Michaela; Carr, Melanie; Streatfield, Claire

    2016-01-01

    We describe a patient in whom long-term, therapeutic infusion of the selective gamma-amino-butyric acid type B (GABAB) receptor agonist, baclofen, into the cerebrospinal fluid (CSF) gave rise to three distinct varieties of memory impairment: i) repeated, short periods of severe global amnesia, ii) accelerated long-term forgetting (ALF), evident over intervals of days and iii) a loss of established autobiographical memories. This pattern of impairment has been reported in patients with temporal lobe epilepsy (TLE), in particular the subtype of Transient Epileptic Amnesia (TEA). The amnesic episodes and accelerated forgetting remitted on withdrawal of baclofen, while the autobiographical amnesia (AbA) persisted. This exceptional case highlights the occurrence of 'non-standard' forms of human amnesia, reflecting the biological complexity of memory processes. It suggests a role for GABAB signalling in the modulation of human memory over multiple time-scales and hints at its involvement in 'epileptic amnesia'.

  13. Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors

    PubMed Central

    Dannemann, Michael; Andrés, Aida M.; Kelso, Janet

    2016-01-01

    Pathogens and the diseases they cause have been among the most important selective forces experienced by humans during their evolutionary history. Although adaptive alleles generally arise by mutation, introgression can also be a valuable source of beneficial alleles. Archaic humans, who lived in Europe and Western Asia for more than 200,000 years, were probably well adapted to this environment and its local pathogens. It is therefore conceivable that modern humans entering Europe and Western Asia who admixed with them obtained a substantial immune advantage from the introgression of archaic alleles. Here we document a cluster of three Toll-like receptors (TLR6-TLR1-TLR10) in modern humans that carries three distinct archaic haplotypes, indicating repeated introgression from archaic humans. Two of these haplotypes are most similar to the Neandertal genome, and the third haplotype is most similar to the Denisovan genome. The Toll-like receptors are key components of innate immunity and provide an important first line of immune defense against bacteria, fungi, and parasites. The unusually high allele frequencies and unexpected levels of population differentiation indicate that there has been local positive selection on multiple haplotypes at this locus. We show that the introgressed alleles have clear functional effects in modern humans; archaic-like alleles underlie differences in the expression of the TLR genes and are associated with reduced microbial resistance and increased allergic disease in large cohorts. This provides strong evidence for recurrent adaptive introgression at the TLR6-TLR1-TLR10 locus, resulting in differences in disease phenotypes in modern humans. PMID:26748514

  14. Receptor for advanced glycation end products contributes to postnatal pulmonary development and adult lung maintenance program in mice.

    PubMed

    Fineschi, Silvia; De Cunto, Giovanna; Facchinetti, Fabrizio; Civelli, Maurizio; Imbimbo, Bruno P; Carnini, Chiara; Villetti, Gino; Lunghi, Benedetta; Stochino, Stefania; Gibbons, Deena L; Hayday, Adrian; Lungarella, Giuseppe; Cavarra, Eleonora

    2013-02-01

    The role of the receptor for advanced glycation end products (RAGE) in promoting the inflammatory response through activation of NF-κB pathway is well established. Recent findings indicate that RAGE may also have a regulative function in apoptosis, as well as in cellular proliferation, differentiation, and adhesion. Unlike other organs, lung tissue in adulthood and during organ development shows relatively high levels of RAGE expression. Thus a role for the receptor in lung organogenesis and homeostasis may be proposed. To evaluate the role of RAGE in lung development and adult lung homeostasis, we generated hemizygous and homozygous transgenic mice overexpressing human RAGE, and analyzed their lungs from the fourth postnatal day to adulthood. Moderate RAGE hyperexpression during lung development influenced secondary septation, resulting in an impairment of alveolar morphogenesis and leading to significant changes in morphometric parameters such as airspace number and the size of alveolar ducts. An increase in alveolar cell apoptosis and a decrease in cell proliferation were demonstrated by the terminal deoxy-nucleotidyltransferase-mediated dUTP nick end labeling reaction, active caspase-3, and Ki-67 immunohistochemistry. Alterations in elastin organization and deposition and in TGF-β expression were observed. In homozygous mice, the hyperexpression of RAGE resulted in histological changes resembling those changes characterizing human bronchopulmonary dysplasia (BPD). RAGE hyperexpression in the adult lung is associated with an increase of the alveolar destructive index and persistent inflammatory status leading to "destructive" emphysema. These results suggest an important role for RAGE in both alveolar development and lung homeostasis, and open new doors to working hypotheses on the pathogenesis of BPD and chronic obstructive pulmonary disease.

  15. Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors.

    PubMed

    Dannemann, Michael; Andrés, Aida M; Kelso, Janet

    2016-01-07

    Pathogens and the diseases they cause have been among the most important selective forces experienced by humans during their evolutionary history. Although adaptive alleles generally arise by mutation, introgression can also be a valuable source of beneficial alleles. Archaic humans, who lived in Europe and Western Asia for more than 200,000 years, were probably well adapted to this environment and its local pathogens. It is therefore conceivable that modern humans entering Europe and Western Asia who admixed with them obtained a substantial immune advantage from the introgression of archaic alleles. Here we document a cluster of three Toll-like receptors (TLR6-TLR1-TLR10) in modern humans that carries three distinct archaic haplotypes, indicating repeated introgression from archaic humans. Two of these haplotypes are most similar to the Neandertal genome, and the third haplotype is most similar to the Denisovan genome. The Toll-like receptors are key components of innate immunity and provide an important first line of immune defense against bacteria, fungi, and parasites. The unusually high allele frequencies and unexpected levels of population differentiation indicate that there has been local positive selection on multiple haplotypes at this locus. We show that the introgressed alleles have clear functional effects in modern humans; archaic-like alleles underlie differences in the expression of the TLR genes and are associated with increased [corrected] microbial resistance and increased allergic disease in large cohorts. This provides strong evidence for recurrent adaptive introgression at the TLR6-TLR1-TLR10 locus, resulting in differences in disease phenotypes in modern humans.

  16. X-Chromosome complement and estrogen receptor signaling independently contribute to the enhanced TLR7-mediated IFN-α production of plasmacytoid dendritic cells from women.

    PubMed

    Laffont, Sophie; Rouquié, Nelly; Azar, Pascal; Seillet, Cyril; Plumas, Joël; Aspord, Caroline; Guéry, Jean-Charles

    2014-12-01

    Human plasmacytoid dendritic cells (pDCs) play a major role in innate immunity through the production of type I IFNs after TLR engagement by pathogens. Sex-based differences in the innate function of human pDCs have been established, with pDCs from women exhibiting enhanced TLR7-mediated IFN-α production as compared with pDCs from males. In mice, we recently provided evidence for a role of estrogens as a positive regulator of pDC innate functions through cell-intrinsic estrogen receptor α signaling, but did not exclude a role for other X-linked factors, particularly in human pDCs. In this study, we investigated the respective contribution of X chromosome dosage and sex hormones using a humanized mouse model in which male or female NOD-SCID-β2m(-/-) were transplanted with human progenitor cells purified from either male or female cord blood cells. We showed that, in response to TLR7 ligands, the frequency of IFN-α- and TNF-α-producing pDCs from either sex was greater in female than in male host mice, suggesting a positive role for estrogens. Indeed, blockade of estrogen receptor signaling during pDC development in vitro inhibited TLR7-mediated IFN-α production by human pDCs, which expressed both ESR1 and ESR2 genes. Interestingly, we also found that X chromosome dosage contributed to this sex bias as female pDCs have an enhanced TLR7-mediated IFN-α response as compared with male ones, irrespective of the sex of the recipient mice. Together, these results indicate that female sex hormones, estrogens, and X chromosome complement independently contribute to the enhanced TLR7-mediated IFN-α response of pDCs in women.

  17. Calcium-sensing receptor activation contributed to apoptosis stimulates TRPC6 channel in rat neonatal ventricular myocytes

    SciTech Connect

    Sun, Yi-hua; Li, Yong-quan; Feng, Shan-li; Li, Bao-xin; Pan, Zhen-wei; Xu, Chang-qing; Li, Ting-ting; Yang, Bao-feng

    2010-04-16

    Capacitative calcium entry (CCE) refers to the influx of calcium through plasma membrane channels activated on depletion of endoplasmic sarcoplasmic/reticulum (ER/SR) Ca{sup 2+} stores, which is performed mainly by the transient receptor potential (TRP) channels. TRP channels are expressed in cardiomyocytes. Calcium-sensing receptor (CaR) is also expressed in rat cardiac tissue and plays an important role in mediating cardiomyocyte apoptosis. However, there are no data regarding the link between CaR and TRP channels in rat heart. In this study, in rat neonatal myocytes, by Ca{sup 2+} imaging, we found that the depletion of ER/SR Ca{sup 2+} stores by thapsigargin (TG) elicited a transient rise in cytoplasmic Ca{sup 2+} ([Ca{sup 2+}]{sub i}), followed by sustained increase depending on extracellular Ca{sup 2+}. But, TRP channels inhibitor (SKF96365), not L-type channels or the Na{sup +}/Ca{sup 2+} exchanger inhibitors, inhibited [Ca{sup 2+}]{sub i} relatively high. Then, we found that the stimulation of CaR with its activator gadolinium chloride (GdCl{sub 3}) or by an increased extracellular Ca{sup 2+}([Ca{sup 2+}]{sub o}) increased the concentration of intracelluar Ca{sup 2+}, whereas, the sustained elevation of [Ca{sup 2+}]{sub i} was reduced in the presence of SKF96365. Similarly, the duration of [Ca{sup 2+}]{sub i} increase was also shortened in the absence of extracellular Ca{sup 2+}. Western blot analysis showed that GdCl{sub 3} increased the expression of TRPC6, which was reversed by SKF96365. Additionally, SKF96365 reduced cardiomyocyte apoptosis induced by GdCl{sub 3}. Our results suggested that CCE exhibited in rat neonatal myocytes and CaR activation induced Ca{sup 2+}-permeable cationic channels TRPCs to gate the CCE, for which TRPC6 was one of the most likely candidates. TRPC6 channel was functionally coupled with CaR to enhance the cardiomyocyte apoptosis.

  18. Contribution of a helix 5 locus to selectivity of hallucinogenic and nonhallucinogenic ligands for the human 5-hydroxytryptamine2A and 5-hydroxytryptamine2C receptors: direct and indirect effects on ligand affinity mediated by the same locus.

    PubMed

    Almaula, N; Ebersole, B J; Ballesteros, J A; Weinstein, H; Sealfon, S C

    1996-07-01

    An important determinant of the neurobehavioral responses induced by a drug is its relative receptor selectivity. The molecular basis of ligand selectivity of hallucinogenic and nonhallucinogenic compounds of varying structural classes for the human 5-hydroxytryptamine (5-HT)2A and 5-HT2C receptors was investigated with the use of reciprocal site-directed mutagenesis. Because these two closely related receptor subtypes differ in the amino acid present at position 5.46 (residues 242 and 222 in the sequences, respectively), the effects of corresponding substitutions in the 5-HT2A[S5.46(242)-->A] and 5-HT2C[A5.46(222)-->S] receptors were studied in tandem. By studying both receptors, the direct and indirect effects of mutations on affinity and selectivity can be distinguished. The ergolines studied, mesulergine (selective for the 5-HT2C receptor) and d-lysergic acid diethylamide (selective for the 5-HT2A receptor), reversed their relative affinity with mutations in each receptor, supporting a direct role of this locus in the selectivity of these ligands. However, interchange mutations in either receptor led to decreased or unchanged affinity for (+/-)-1-)(2,5-dimethoxy-4-iodophenyl)-2-aminopropane and ketanserin, which have higher affinity for the 5-HT2A receptor, consistent with little contribution of this locus to the selectivity of these ligands. The indoleamines studied were affected differently by mutations in each receptor, suggesting that they bind differently to the two receptor subtypes. Mutation of this locus in the 5-HT2A receptor decreased the affinity of all indoleamines, whereas the interchange mutation of the 5-HT2C receptor did not affect indoleamine affinity. These results are consistent with a direct interaction between this side chain and indoleamines for the 5-HT2A receptor but not for the 5-HT2C receptor. Furthermore, this analysis shows that the higher affinity of 5-HT and tryptamine for the 5-HT2C receptor than for the 5-HT2A receptors is not

  19. Oxytocin and vasopressin receptor polymorphisms interact with circulating neuropeptides to predict human emotional reactions to stress

    PubMed Central

    Moons, Wesley G.; Way, Baldwin M.; Taylor, Shelley E.

    2014-01-01

    Oxytocin (OT) and a polymorphism (rs53576) in the oxytocin receptor gene (OXTR) have been independently associated with stress reactivity, whereas oxytocin’s sister peptide, arginine vasopressin (AVP), and polymorphisms in the vasopressin receptor gene (AVPR1A) have been independently associated with aggressive behavior. In this study, 68 men and 98 women were genotyped for the OXTR rs53576 polymorphism and the AVPR1A RS1 polymorphism. Baseline and post-stressor levels of plasma OT, plasma AVP, positive affect, and anger were assessed. Women, but not men, with high levels of post-stressor OT and the GG genotype of rs53576 felt the most positive affect after the stressor. Men, but not women, with high levels of post-stressor AVP and with the 320allele of the RS1 polymorphism reported more post-stressor anger than non-carriers. These data constitute the first evidence that oxytocin and vasopressin receptor genes interact with levels of OT and AVP to predict sex-specific emotional stress responses. PMID:24660771

  20. A highly pleiotropic amino acid polymorphism in the Drosophila insulin receptor contributes to life-history adaptation

    PubMed Central

    Paaby, Annalise B.; Bergland, Alan O.; Behrman, Emily L.; Schmidt, Paul S.

    2016-01-01

    Finding the specific nucleotides that underlie adaptive variation is a major goal in evolutionary biology, but polygenic traits pose a challenge because the complex genotype–phenotype relationship can obscure the effects of individual alleles. However, natural selection working in large wild populations can shift allele frequencies and indicate functional regions of the genome. Previously, we showed that the two most common alleles of a complex amino acid insertion–deletion polymorphism in the Drosophila insulin receptor show independent, parallel clines in frequency across the North American and Australian continents. Here, we report that the cline is stable over at least a five-year period and that the polymorphism also demonstrates temporal shifts in allele frequency concurrent with seasonal change. We tested the alleles for effects on levels of insulin signaling, fecundity, development time, body size, stress tolerance, and life span. We find that the alleles are associated with predictable differences in these traits, consistent with patterns of Drosophila life-history variation across geography that likely reflect adaptation to the heterogeneous climatic environment. These results implicate insulin signaling as a major mediator of life-history adaptation in Drosophila, and suggest that life-history trade-offs can be explained by extensive pleiotropy at a single locus. PMID:25319083

  1. Angiotensin Type 1a Receptors on Corticotropin-Releasing Factor Neurons Contribute to the Expression of Conditioned Fear

    PubMed Central

    Hurt, Robert C.; Garrett, Jacob C.; Keifer, Orion P.; Linares, Andrea; Couling, Leena; Speth, Robert C.; Ressler, Kerry J.; Marvar, Paul J.

    2015-01-01

    Although generally associated with cardiovascular regulation, angiotensin II receptor type 1 (AT1aR) blockade in mouse models and humans has also been associated with enhanced fear extinction and decreased post-traumatic stress disorder (PTSD) symptom severity, respectively. The mechanisms mediating these effects remain unknown, but may involve alterations in the activities of corticotropin-releasing factor (CRF)-expressing cells, which are known to be involved in fear regulation. To test the hypothesis that AT1aR signaling in CRFergic neurons is involved in conditioned fear expression, we generated and characterized a conditional knockout mouse strain with a deletion of the AT1aR gene from its CRF-releasing cells (CRF-AT1aR(−/−)). These mice exhibit normal baseline heart rate, blood pressure, anxiety, and locomotion, and freeze at normal levels during acquisition of auditory fear conditioning. However, CRF-AT1aR(−/−) mice exhibit less freezing than wild type mice during tests of conditioned fear expression—an effect that may be caused by a decrease in the consolidation of fear memory. These results suggest that central AT1R activity in CRF-expressing cells plays a role in the expression of conditioned fear, and identify CRFergic cells as a population on which AT1R antagonists may act to modulate fear extinction. PMID:26257395

  2. Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine

    PubMed Central

    Virsolvy, Anne; Farah, Charlotte; Pertuit, Nolwenn; Kong, Lingyan; Lacampagne, Alain; Reboul, Cyril; Aimond, Franck; Richard, Sylvain

    2015-01-01

    Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na+ current (INa), and is known to reduce the Na+-dependent Ca2+ overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na+ channels (Nav) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote INa. We observed that in the presence of the Nav channel agonist veratridine, ranolazine inhibited INa and intracellular Ca2+ calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Nav channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α1-adrenergic receptor. Combined α1-adrenergic antagonization and inhibition of SMCs Nav channels could be involved in the vascular effects of ranolazine. PMID:26655634

  3. Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine.

    PubMed

    Virsolvy, Anne; Farah, Charlotte; Pertuit, Nolwenn; Kong, Lingyan; Lacampagne, Alain; Reboul, Cyril; Aimond, Franck; Richard, Sylvain

    2015-12-10

    Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na(+) current (INa), and is known to reduce the Na(+)-dependent Ca(2+) overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na(+) channels (Nav) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote INa. We observed that in the presence of the Nav channel agonist veratridine, ranolazine inhibited INa and intracellular Ca(2+) calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Nav channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α1-adrenergic receptor. Combined α1-adrenergic antagonization and inhibition of SMCs Nav channels could be involved in the vascular effects of ranolazine.

  4. Expression of the aryl hydrocarbon receptor contributes to the establishment of intestinal microbial community structure in mice

    PubMed Central

    Murray, Iain A.; Nichols, Robert G.; Zhang, Limin; Patterson, Andrew D.; Perdew, Gary H.

    2016-01-01

    Environmental and genetic factors represent key components in the establishment/maintenance of the intestinal microbiota. The aryl hydrocarbon receptor (AHR) is emerging as a pleiotropic factor, modulating pathways beyond its established role as a xenobiotic sensor. The AHR is known to regulate immune surveillance within the intestine through retention of intraepithelial lymphocytes, functional redistribution of Th17/Treg balance. Consequently, environmental/genetic manipulation of AHR activity likely influences host-microbe homeostasis. Utilizing C57BL6/J Ahr−/+ and Ahr−/− co-housed littermates followed by 18 days of genotypic segregation, we examined the influence of AHR expression upon intestinal microbe composition/functionality and host physiology. 16S sequencing/quantitative PCR (qPCR) revealed significant changes in phyla abundance, particularly Verrucomicrobia together with segmented filamentous bacteria, and an increase in species diversity in Ahr−/− mice following genotypic segregation. Metagenomics/metabolomics indicate microbial composition is associated with functional shifts in bacterial metabolism. Analysis identified Ahr−/−-dependent increases in ileal gene expression, indicating increased inflammatory tone. Transfer of Ahr−/− microbiota to wild-type germ-free mice recapitulated the increase Verrucomicrobia and inflammatory tone, indicating Ahr−/−-microbial dependence. These data suggest a role for the AHR in influencing the community structure of the intestinal microbiota. PMID:27659481

  5. Annexin A1 contributes to pancreatic cancer cell phenotype, behaviour and metastatic potential independently of Formyl Peptide Receptor pathway

    PubMed Central

    Belvedere, Raffaella; Bizzarro, Valentina; Forte, Giovanni; Dal Piaz, Fabrizio; Parente, Luca; Petrella, Antonello

    2016-01-01

    Annexin A1 (ANXA1) is a Ca2+-binding protein over-expressed in pancreatic cancer (PC). We recently reported that extracellular ANXA1 mediates PC cell motility acting on Formyl Peptide Receptors (FPRs). Here, we describe other mechanisms by which intracellular ANXA1 could mediate PC progression. We obtained ANXA1 Knock-Out (KO) MIA PaCa-2 cells using the CRISPR/Cas9 genome editing technology. LC-MS/MS analysis showed altered expression of several proteins involved in cytoskeletal organization. As a result, ANXA1 KO MIA PaCa-2 partially lost their migratory and invasive capabilities with a mechanism that appeared independent of FPRs. The acquisition of a less aggressive phenotype has been further investigated in vivo. Wild type (WT), PGS (scrambled) and ANXA1 KO MIA PaCa-2 cells were engrafted orthotopically in SCID mice. No differences were found about PC primary mass, conversely liver metastatization appeared particularly reduced in ANXA1 KO MIA PaCa-2 engrafted mice. In summary, we show that intracellular ANXA1 is able to preserve the cytoskeleton integrity and to maintain a malignant phenotype in vitro. The protein has a relevant role in the metastatization process in vivo, as such it appears attractive and suitable as prognostic and therapeutic marker in PC progression. PMID:27412958

  6. Toll-like receptor 4-induced endoplasmic reticulum stress contributes to impairment of vasodilator action of insulin

    PubMed Central

    Jang, Hyun-Ju; Hwang, Daniel H.

    2015-01-01

    Impairment of vasodilator action of insulin is associated with endothelial dysfunction and insulin resistance. Activation of Toll-like receptor 4 (TLR4) induces proinflammatory response and endoplasmic reticulum (ER) stress. Saturated fatty acids (SFA) activate TLR4, which induces ER stress and endothelial dysfunction. Therefore, we determined whether TLR4-mediated ER stress is an obligatory step mediating SFA-induced endothelial dysfunction. Palmitate stimulated proinflammatory responses and ER stress, and this was suppressed by knockdown of TLR4 in primary human aortic endothelial cells (HAEC). Next, we examined the role of TLR4 in vasodilatory responses in intact vessels isolated from wild-type (WT, C57BL/6) and TLR4-KO mice after feeding high-fat (HFD) or normal chow diet (NCD) for 12 wk. Arterioles isolated from HFD WT mice exhibited impaired insulin-stimulated vasodilation compared with arterioles isolated from NCD WT mice. Deficiency of TLR4 was protective from HFD-induced impairment of insulin-stimulated vasodilation. There were no differences in acetylcholine (Ach)- or sodium nitroprusside (SNP)-stimulated vasodilation between the two groups. Furthermore, we examined whether ER stress is involved in SFA-induced impairment of vasodilator actions of insulin. Infusion of palmitate showed the impairment of vasodilatory response to insulin, which was ameliorated by coinfusion with tauroursodeoxycholic acid (TUDCA), an ER stress suppressor. Taken together, the results suggest that TLR4-induced ER stress may be an obligatory step mediating the SFA-mediated endothelial dysfunction. PMID:26522062

  7. Angiotensin type 1a receptors on corticotropin-releasing factor neurons contribute to the expression of conditioned fear.

    PubMed

    Hurt, R C; Garrett, J C; Keifer, O P; Linares, A; Couling, L; Speth, R C; Ressler, K J; Marvar, P J

    2015-09-01

    Although generally associated with cardiovascular regulation, angiotensin II receptor type 1a (AT1a R) blockade in mouse models and humans has also been associated with enhanced fear extinction and decreased post-traumatic stress disorder (PTSD) symptom severity, respectively. The mechanisms mediating these effects remain unknown, but may involve alterations in the activities of corticotropin-releasing factor (CRF)-expressing cells, which are known to be involved in fear regulation. To test the hypothesis that AT1a R signaling in CRFergic neurons is involved in conditioned fear expression, we generated and characterized a conditional knockout mouse strain with a deletion of the AT1a R gene from its CRF-releasing cells (CRF-AT1a R((-/-)) ). These mice exhibit normal baseline heart rate, blood pressure, anxiety and locomotion, and freeze at normal levels during acquisition of auditory fear conditioning. However, CRF-AT1a R((-/-)) mice exhibit less freezing than wild-type mice during tests of conditioned fear expression-an effect that may be caused by a decrease in the consolidation of fear memory. These results suggest that central AT1a R activity in CRF-expressing cells plays a role in the expression of conditioned fear, and identify CRFergic cells as a population on which AT1 R antagonists may act to modulate fear extinction.

  8. Glucocorticoid receptor signaling contributes to constitutive activation of the noncanonical NF-κB pathway in term human placenta.

    PubMed

    Wang, Bingbing; Palomares, Kristy; Parobchak, Nataliya; Cece, John; Rosen, Max; Nguyen, Anh; Rosen, Todd

    2013-02-01

    Our recent study demonstrated that constitutively activated RelB/NF-κB2 positively regulates the CRH in the human placenta. In the current study, we explored the role of the glucocorticoid receptor (GR) signaling in constitutive activation of the noncanonical NF-κB pathway. A glucocorticoid response element (GRE) motif search suggests that both NF-κB inducing kinase (NIK) and RelB genes, which are key regulators of the noncanonical NF-κB pathway, have a putative GRE within their promoter, approximately 1 kb upstream from the transcription start site. By using chromatin immunoprecipitation assay we identified that the GR and phosphorylated GR at Ser211 were associated with the GREs of both NIK and RelB. Dexamethasone stimulated expression of NIK, RelB, NF-κB2 as well as CRH and cyclooxygenase-2 (COX-2). Repression of GR by short interfering RNA resulted in inhibition of NIK, RelB, NF-κB2, CRH, and COX-2. In addition, depletion of GR attenuated glucocorticoid-mediated up-regulation of NIK, RelB, NF-κB2, CRH, and COX-2. Furthermore, siRNA specifically targeting NIK down-regulated CRH and COX-2. Taken together, these results suggest that constitutive activation of the noncanonical NF-κB pathway in term human placenta is driven by the GR signaling, which in turn up-regulates placental CRH and other NF-κB-responsive genes.

  9. The toll-like receptor signaling molecule Myd88 contributes to pancreatic beta-cell homeostasis in response to injury.

    PubMed

    Bollyky, Paul L; Bice, Jeffrey B; Sweet, Ian R; Falk, Ben A; Gebe, John A; Clark, April E; Gersuk, Vivian H; Aderem, Alan; Hawn, Thomas R; Nepom, Gerald T

    2009-01-01

    Commensal flora and pathogenic microbes influence the incidence of diabetes in animal models yet little is known about the mechanistic basis of these interactions. We hypothesized that Myd88, an adaptor molecule in the Toll-like-receptor (TLR) pathway, regulates pancreatic beta-cell function and homeostasis. We first examined beta-cells histologically and found that Myd88-/- mice have smaller islets in comparison to C57Bl/6 controls. Myd88-/- mice were nonetheless normoglycemic both at rest and after an intra-peritoneal glucose tolerance test (IPGTT). In contrast, after low-dose streptozotocin (STZ) challenge, Myd88-/-mice had an abnormal IPGTT relative to WT controls. Furthermore, Myd88-/- mice suffer enhanced beta-cell apoptosis and have enhanced hepatic damage with delayed recovery upon low-dose STZ treatment. Finally, we treated WT mice with broad-spectrum oral antibiotics to deplete their commensal flora. In WT mice, low dose oral lipopolysaccharide, but not lipotichoic acid or antibiotics alone, strongly promoted enhanced glycemic control. These data suggest that Myd88 signaling and certain TLR ligands mediate a homeostatic effect on beta-cells primarily in the setting of injury.

  10. The Toll-Like Receptor Signaling Molecule Myd88 Contributes to Pancreatic Beta-Cell Homeostasis in Response to Injury

    PubMed Central

    Bollyky, Paul L.; Bice, Jeffrey B.; Sweet, Ian R.; Falk, Ben A.; Gebe, John A.; Clark, April E.; Gersuk, Vivian H.; Aderem, Alan; Hawn, Thomas R.; Nepom, Gerald T.

    2009-01-01

    Commensal flora and pathogenic microbes influence the incidence of diabetes in animal models yet little is known about the mechanistic basis of these interactions. We hypothesized that Myd88, an adaptor molecule in the Toll-like-receptor (TLR) pathway, regulates pancreatic β-cell function and homeostasis. We first examined β-cells histologically and found that Myd88−/− mice have smaller islets in comparison to C57Bl/6 controls. Myd88−/− mice were nonetheless normoglycemic both at rest and after an intra-peritoneal glucose tolerance test (IPGTT). In contrast, after low-dose streptozotocin (STZ) challenge, Myd88−/−mice had an abnormal IPGTT relative to WT controls. Furthermore, Myd88−/− mice suffer enhanced β-cell apoptosis and have enhanced hepatic damage with delayed recovery upon low-dose STZ treatment. Finally, we treated WT mice with broad-spectrum oral antibiotics to deplete their commensal flora. In WT mice, low dose oral lipopolysaccharide, but not lipotichoic acid or antibiotics alone, strongly promoted enhanced glycemic control. These data suggest that Myd88 signaling and certain TLR ligands mediate a homeostatic effect on β-cells primarily in the setting of injury. PMID:19357791

  11. Toll-like receptor 4 signaling in neurons of trigeminal ganglion contributes to nociception induced by acute pulpitis in rats

    PubMed Central

    Lin, Jia-Ji; Du, Yi; Cai, Wen-Ke; Kuang, Rong; Chang, Ting; Zhang, Zhuo; Yang, Yong-Xiang; Sun, Chao; Li, Zhu-Yi; Kuang, Fang

    2015-01-01

    Pain caused by acute pulpitis (AP) is a common symptom in clinical settings. However, its underlying mechanisms have largely remained unknown. Using AP model, we demonstrated that dental injury caused severe pulp inflammation with up-regulated serum IL-1β. Assessment from head-withdrawal reflex thresholds (HWTs) and open-field test demonstrated nociceptive response at 1 day post injury. A consistent up-regulation of Toll-like receptor 4 (TLR4) in the trigeminal ganglion (TG) ipsilateral to the injured pulp was found; and downstream signaling components of TLR4, including MyD88, TRIF and NF-κB, and cytokines such as TNF-α and IL-1β, were also increased. Retrograde labeling indicated that most TLR4 positve neuron in the TG innnervated the pulp and TLR4 immunoreactivity was mainly in the medium and small neurons. Double labeling showed that the TLR4 expressing neurons in the ipsilateral TG were TRPV1 and CGRP positive, but IB4 negative. Furthermore, blocking TLR4 by eritoran (TLR4 antagonist) in TGs of the AP model significantly down-regulated MyD88, TRIF, NF-κB, TNF-α and IL-1β production and behavior of nociceptive response. Our findings suggest that TLR4 signaling in TG cells, particularly the peptidergic TRPV1 neurons, plays a key role in AP-induced nociception, and indicate that TLR4 signaling could be a potential therapeutic target for orofacial pain. PMID:26224622

  12. Oxytocin and Vasopressin Receptor Gene Variation as a Proximate Base for Inter- and Intraspecific Behavioral Differences in Bonobos and Chimpanzees

    PubMed Central

    Staes, Nicky; Stevens, Jeroen M. G.; Helsen, Philippe; Hillyer, Mia; Korody, Marisa; Eens, Marcel

    2014-01-01

    Recent literature has revealed the importance of variation in neuropeptide receptor gene sequences in the regulation of behavioral phenotypic variation. Here we focus on polymorphisms in the oxytocin receptor gene (OXTR) and vasopressin receptor gene 1a (Avpr1a) in chimpanzees and bonobos. In humans, a single nucleotide polymorphism (SNP) in the third intron of OXTR (rs53576 SNP (A/G)) is linked with social behavior, with the risk allele (A) carriers showing reduced levels of empathy and prosociality. Bonobos and chimpanzees differ in these same traits, therefore we hypothesized that these differences might be reflected in variation at the rs53576 position. We sequenced a 320 bp region surrounding rs53576 but found no indications of this SNP in the genus Pan. However, we identified previously unreported SNP variation in the chimpanzee OXTR sequence that differs from both humans and bonobos. Humans and bonobos have previously been shown to have a more similar 5′ promoter region of Avpr1a when compared to chimpanzees, who are polymorphic for the deletion of ∼360 bp in this region (+/− DupB) which includes a microsatellite (RS3). RS3 has been linked with variation in levels of social bonding, potentially explaining part of the interspecies behavioral differences found in bonobos, chimpanzees and humans. To date, results for bonobos have been based on small sample sizes. Our results confirmed that there is no DupB deletion in bonobos with a sample size comprising approximately 90% of the captive founder population, whereas in chimpanzees the deletion of DupB had the highest frequency. Because of the higher frequency of DupB alleles in our bonobo population, we suggest that the presence of this microsatellite may partly reflect documented differences in levels of sociability found in bonobos and chimpanzees. PMID:25405348

  13. Toll-like receptors 2 and 4 contribute to sepsis-induced depletion of spleen dendritic cells.

    PubMed

    Pène, Frédéric; Courtine, Emilie; Ouaaz, Fatah; Zuber, Benjamin; Sauneuf, Bertrand; Sirgo, Gonzalo; Rousseau, Christophe; Toubiana, Julie; Balloy, Viviane; Chignard, Michel; Mira, Jean-Paul; Chiche, Jean-Daniel

    2009-12-01

    Depletion of dendritic cells (DC) in secondary lymphoid organs is a hallmark of sepsis-induced immune dysfunction. In this setting, we investigated if Toll-like receptor (TLR)-dependent signaling might modulate the maturation process and the survival of DC. Using a model of sublethal polymicrobial sepsis induced by cecal ligation and puncture, we investigated the quantitative and functional features of spleen DC in wild-type, TLR2(-/-), TLR4(-/-), and TLR2(-/-) TLR4(-/-) mice. By 24 h, a decrease in the relative percentage of CD11c(high) spleen DC occurred in wild-type mice but was prevented in TLR2(-/-), TLR4(-/-), and TLR2(-/-) TLR4(-/-) mice. In wild-type mice, sepsis dramatically affected both CD11c(+) CD8alpha(+) and CD11c(+) CD8alpha(-) subsets. In all three types of knockout mice studied, the CD11c(+) CD8alpha(+) subset followed a depletion pattern similar to that for wild-type mice. In contrast, the loss of CD11c(+) CD8alpha(-) cells was attenuated in TLR2(-/-) and TLR4(-/-) mice and completely prevented in TLR2(-/-) TLR4(-/-) mice. Accordingly, apoptosis of spleen DC was increased in septic wild-type mice and inhibited in knockout mice. In addition we characterized the functional features of spleen DC obtained from septic mice. As shown by increased expression of major histocompatibility complex class II and CD86, polymicrobial sepsis induced maturation of DC, with subsequent increased capacity to prime T lymphocytes, similarly in wild-type and knockout mice. In response to CpG DNA stimulation, production of interleukin-12 was equally impaired in DC obtained from wild-type and knockout septic mice. In conclusion, although dispensable for the DC maturation process, TLR2 and TLR4 are involved in the mechanisms leading to depletion of spleen DC following polymicrobial sepsis.

  14. Spinal interleukin-33 and its receptor ST2 contribute to bone cancer-induced pain in mice.

    PubMed

    Zhao, J; Zhang, H; Liu, S-B; Han, P; Hu, S; Li, Q; Wang, Z-F; Mao-Ying, Q-L; Chen, H-M; Jiang, J-W; Wu, G-C; Mi, W-L; Wang, Y-Q

    2013-12-03

    Cancer pain, particularly bone cancer pain, affects the quality of life of cancer patients, and current treatments are limited. Interleukin (IL)-33, a new member of the IL-1 super family, has been reported to be involved in the modulation of inflammatory pain. However, studies focused on its role in the modulation of cancer pain have been rare. The present study was designed to investigate whether spinal IL-33/ST2 signaling was involved in bone cancer-induced pain in mice. Bone cancer was induced via intra-femoral inoculation of 4T1 mammary carcinoma cells. The mice inoculated with carcinoma cells showed mechanical allodynia, heat hyperalgesia and a reduction in limb use, whereas phosphate-buffered saline or heat-killed cells-injected mice showed no significant difference compared to non-treated mice. The pain hypersensitive behaviors worsened over time and with bone destruction. Both the mRNA and the protein levels of IL-33 and relative cytokines (IL-1β, IL-6, TNF-a) were significantly increased in the spinal cord after the inoculation of carcinoma cells. Intrathecal administration of ST2 antibody to block IL-33/ST2 signaling alleviated pain behaviors in a dose-dependent manner in bone cancer pain mice compared with vehicle-injected mice. Moreover, the ST2(-/-) mice showed a significant amelioration of limb use and heat hyperalgesia compared to wild-type mice. Meanwhile, concentrations of spinal IL-1β, IL-6 and TNF-a in the cancer-bearing ST2(-/-) mice had no significant changes. These data further suggested that IL-33/ST2 signaling played a vital role in cancer pain. Our results provided evidence that IL-33 and its receptor ST2 may be a potential therapeutic target for the treatment of pain in bone cancer patients.

  15. Molecular mechanisms contributing to TARP regulation of channel conductance and polyamine block of calcium-permeable AMPA receptors.

    PubMed

    Soto, David; Coombs, Ian D; Gratacòs-Batlle, Esther; Farrant, Mark; Cull-Candy, Stuart G

    2014-08-27

    Many properties of fast synaptic transmission in the brain are influenced by transmembrane AMPAR regulatory proteins (TARPs) that modulate the pharmacology and gating of AMPA-type glutamate receptors (AMPARs). Although much is known about TARP influence on AMPAR pharmacology and kinetics through their modulation of the extracellular ligand-binding domain (LBD), less is known about their regulation of the ion channel region. TARP-induced modifications in AMPAR channel behavior include increased single-channel conductance and weakened block of calcium-permeable AMPARs (CP-AMPARs) by endogenous intracellular polyamines. To investigate how TARPs modify ion flux and channel block, we examined the action of γ-2 (stargazin) on GluA1 and GluA4 CP-AMPARs. First, we compared the permeation of organic cations of different sizes. We found that γ-2 increased the permeability of several cations but not the estimated AMPAR pore size, suggesting that TARP-induced relief of polyamine block does not reflect altered pore diameter. Second, to determine whether residues in the TARP intracellular C-tail regulate polyamine block and channel conductance, we examined various γ-2 C-tail mutants. We identified the membrane proximal region of the C terminus as crucial for full TARP-attenuation of polyamine block, whereas complete deletion of the C-tail markedly enhanced the TARP-induced increase in channel conductance; thus, the TARP C-tail influences ion permeation. Third, we identified a site in the pore-lining region of the AMPAR, close to its Q/R site, that is crucial in determining the TARP-induced changes in single-channel conductance. This conserved residue represents a site of TARP action, independent of the AMPAR LBD.

  16. Oestrogen receptorcontributes to the regulation of the hedgehog signalling pathway in ERα-positive gastric cancer

    PubMed Central

    Kameda, C; Nakamura, M; Tanaka, H; Yamasaki, A; Kubo, M; Tanaka, M; Onishi, H; Katano, M

    2010-01-01

    Background: Oestrogen receptor-alpha (ERα) is highly expressed in diffuse-type gastric cancer and oestrogen increases the proliferation of ERα-positive gastric cancer. However, a detailed mechanism by which oestrogen increases the proliferation of these cells is still unclear. Methods: We used 17-β-oestradiol (E2) as a stimulator against the ERα pathway. Pure anti-oestrogen drug ICI 182 780 (ICI) and small interfering RNA against ERα (ERα siRNA) were used as inhibitors. Cyclopamine (Cyc) was used as the hedgehog (Hh) pathway inhibitor. Two human ERα-positive gastric cancer cells were used as target cells. Effects of the stimulator and inhibitor on E2-induced cell proliferation were also examined. Results: In ERα-positive cells, E2 increased not only cell proliferation but also one of the ligands of the Hh pathway, Shh expression. 17-β-Oestradiol-induced cell proliferation was suppressed by ICI, ERα siRNA or Cyc. The increased expression of Shh induced by E2 was suppressed by ICI and ERα siRNA but not by Cyc. Furthermore, recombinant Shh activated the Hh pathway and increased cell proliferation, whereas anti-Shh antibody suppressed E2-induced cell proliferation. When a relationship between ERα and Shh expressions was analysed using surgically resected gastric cancer specimens, a positive correlation was found, suggesting a linkage between the ERα and Hh pathways. Conclusion: Our data indicate that activation of the ERα pathway promotes cell proliferation by activating the Hh pathway in a ligand-dependent manner through Shh induction of ERα-positive gastric cancer. PMID:20087349

  17. Molecular Mechanisms Contributing to TARP Regulation of Channel Conductance and Polyamine Block of Calcium-Permeable AMPA Receptors

    PubMed Central

    Coombs, Ian D.; Gratacòs-Batlle, Esther

    2014-01-01

    Many properties of fast synaptic transmission in the brain are influenced by transmembrane AMPAR regulatory proteins (TARPs) that modulate the pharmacology and gating of AMPA-type glutamate receptors (AMPARs). Although much is known about TARP influence on AMPAR pharmacology and kinetics through their modulation of the extracellular ligand-binding domain (LBD), less is known about their regulation of the ion channel region. TARP-induced modifications in AMPAR channel behavior include increased single-channel conductance and weakened block of calcium-permeable AMPARs (CP-AMPARs) by endogenous intracellular polyamines. To investigate how TARPs modify ion flux and channel block, we examined the action of γ-2 (stargazin) on GluA1 and GluA4 CP-AMPARs. First, we compared the permeation of organic cations of different sizes. We found that γ-2 increased the permeability of several cations but not the estimated AMPAR pore size, suggesting that TARP-induced relief of polyamine block does not reflect altered pore diameter. Second, to determine whether residues in the TARP intracellular C-tail regulate polyamine block and channel conductance, we examined various γ-2 C-tail mutants. We identified the membrane proximal region of the C terminus as crucial for full TARP-attenuation of polyamine block, whereas complete deletion of the C-tail markedly enhanced the TARP-induced increase in channel conductance; thus, the TARP C-tail influences ion permeation. Third, we identified a site in the pore-lining region of the AMPAR, close to its Q/R site, that is crucial in determining the TARP-induced changes in single-channel conductance. This conserved residue represents a site of TARP action, independent of the AMPAR LBD. PMID:25164663

  18. AMPA/kainate glutamate receptors contribute to inflammation, degeneration and pain related behaviour in inflammatory stages of arthritis

    PubMed Central

    Bonnet, Cleo S; Williams, Anwen S; Gilbert, Sophie J; Harvey, Ann K; Evans, Bronwen A; Mason, Deborah J

    2015-01-01

    Objectives Synovial fluid glutamate concentrations increase in arthritis. Activation of kainate (KA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors (GluRs) increase interleukin-6 (IL-6) release and cause arthritic pain, respectively. We hypothesised that AMPA and KA GluRs are expressed in human arthritis, and that intra-articular NBQX (AMPA/KA GluR antagonist) prevents pain and pathology in antigen-induced arthritis (AIA). Methods GluR immunohistochemistry was related to synovial inflammation and degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). A single intra-articular NBQX injection was given at induction, and knee swelling and gait of AIA and AIA+NBQX rats compared over 21 days, before imaging, RT-qPCR, histology and immunohistochemistry of joints. Effects of NBQX on human primary osteoblast (HOB) activity were determined. Results AMPAR2 and KA1 immunolocalised to remodelling bone, cartilage and synovial cells in human OA and RA, and rat AIA. All arthritic tissues showed degradation and synovial inflammation. NBQX reduced GluR abundance, knee swelling (p<0.001, days 1–21), gait abnormalities (days 1–2), end-stage joint destruction (p<0.001), synovial inflammation (p<0.001), and messenger RNA expression of meniscal IL-6 (p<0.05) and whole joint cathepsin K (p<0.01). X-ray and MRI revealed fewer cartilage and bone erosions, and less inflammation after NBQX treatment. NBQX reduced HOB number and prevented mineralisation. Conclusions AMPA/KA GluRs are expressed in human OA and RA, and in AIA, where a single intra-articular injection of NBQX reduced swelling by 33%, and inflammation and degeneration scores by 34% and 27%, respectively, exceeding the efficacy of approved drugs in the same model. AMPA/KA GluR antagonists represent a potential treatment for arthritis. PMID:24130267

  19. Multiscale Mechanical Model of the Pacinian Corpuscle Shows Depth and Anisotropy Contribute to the Receptor's Characteristic Response to Indentation.

    PubMed

    Quindlen, Julia C; Lai, Victor K; Barocas, Victor H

    2015-09-01

    Cutaneous mechanoreceptors transduce different tactile stimuli into neural signals that produce distinct sensations of touch. The Pacinian corpuscle (PC), a cutaneous mechanoreceptor located deep within the dermis of the skin, detects high frequency vibrations that occur within its large receptive field. The PC is comprised of lamellae that surround the nerve fiber at its core. We hypothesized that a layered, anisotropic structure, embedded deep within the skin, would produce the nonlinear strain transmission and low spatial sensitivity characteristic of the PC. A multiscale finite-element model was used to model the equilibrium response of the PC to indentation. The first simulation considered an isolated PC with fiber networks aligned with the PC's surface. The PC was subjected to a 10 μm indentation by a 250 μm diameter indenter. The multiscale model captured the nonlinear strain transmission through the PC, predicting decreased compressive strain with proximity to the receptor's core, as seen experimentally by others. The second set of simulations considered a single PC embedded epidermally (shallow) or dermally (deep) to model the PC's location within the skin. The embedded models were subjected to 10 μm indentations at a series of locations on the surface of the skin. Strain along the long axis of the PC was calculated after indentation to simulate stretch along the nerve fiber at the center of the PC. Receptive fields for the epidermis and dermis models were constructed by mapping the long-axis strain after indentation at each point on the surface of the skin mesh. The dermis model resulted in a larger receptive field, as the calculated strain showed less indenter location dependence than in the epidermis model.

  20. BDNF contributes to both rapid and homeostatic alterations in AMPA receptor surface expression in nucleus accumbens medium spiny neurons

    PubMed Central

    Reimers, Jeremy M.; Loweth, Jessica A.; Wolf, Marina E.

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) plays a critical role in plasticity at glutamate synapses and the effects of repeated cocaine exposure. We recently showed that intracranial injection of BDNF into the rat nucleus accumbens (NAc), a key region for cocaine addiction, rapidly increases AMPA receptor (AMPAR) surface expression. To further characterize BDNF’s role in both rapid AMPAR trafficking and slower, homeostatic changes in AMPAR surface expression, we investigated the effects of acute (30 min) and long-term (24 h) treatment with BDNF on AMPAR distribution in NAc medium spiny neurons from postnatal rats co-cultured with mouse prefrontal cortex (PFC) neurons to restore excitatory inputs. Immunocytochemical studies showed that acute BDNF treatment increased cell surface GluA1 and GluA2 levels, as well as their co-localization, on NAc neurons. This effect of BDNF, confirmed using a protein crosslinking assay, was dependent on ERK but not AKT signaling. In contrast, long-term BDNF treatment decreased AMPAR surface expression on NAc neurons. Based on this latter result, we tested the hypothesis that BDNF plays a role in AMPAR “scaling down” in response to a prolonged increase in neuronal activity produced by bicuculline (24 h). Supporting this hypothesis, decreasing BDNF signaling with the extracellular BDNF scavenger TrkB-Fc prevented the scaling down of GluA1 and GluA2 surface levels in NAc neurons normally produced by bicuculline. In conclusion, BDNF exerts bidirectional effects on NAc AMPAR surface expression, depending on duration of exposure. Furthermore, BDNF’s involvement in synaptic scaling in the NAc differs from its previously described role in the visual cortex. PMID:24712995

  1. Redundant signaling mechanisms contribute to the vasodilatory response of the afferent arteriole to proteinase-activated receptor-2.

    PubMed

    Wang, Xuemei; Hollenberg, Morley D; Loutzenhiser, Rodger

    2005-01-01

    We previously demonstrated that stimulation of proteinase-activated receptor-2 (PAR-2) by SLIGRL-NH(2) elicits afferent arteriolar vasodilation, in part, by elaborating nitric oxide (NO), suggesting an endothelium-dependent mechanism (Trottier G, Hollenberg M, Wang X, Gui Y, Loutzenhiser K, and Loutzenhiser R. Am J Physiol Renal Physiol 282: F891-F897, 2002). In the present study, we characterized the NO-independent component of this response, using the in vitro perfused hydronephrotic rat kidney. SLIGRL-NH(2) (10 mumol/l) dilated afferent arterioles preconstricted with ANG II, and the initial transient component of this response was resistant to NO synthase (NOS) and cyclooxygenase inhibition. This NO-independent response was not prevented by treatment with 10 nmol/l charybdotoxin and 1 mumol/l apamin, a manipulation that prevents the endothelium-derived hyperpolarizing factor (EDHF)-like response of the afferent arteriole to acetylcholine, nor was it blocked by the addition of 1 mmol/l tetraethylammonium (TEA) or 50 mumol/l 17-octadecynoic acid, treatments that block the EDHF-like response to bradykinin. To determine whether the PAR-2 response additionally involves the electrogenic Na(+)-K(+)-ATPase, responses were evaluated in the presence of 3 mmol/l ouabain. In this setting, SLIGRL-NH(2) induced a biphasic dilation in control and a transient response after NOS inhibition. The latter was not prevented by charybdotoxin plus apamin or by TEA alone but was abolished by combined treatment with charybdotoxin, apamin, and TEA. This treatment did not prevent the NO-dependent dilation evoked in the absence of NOS inhibition. Our findings indicate a remarkable redundancy in the signaling cascade mediating PAR-2 -induced afferent arteriolar vasodilation, suggesting an importance in settings such as inflamation or ischemia, in which vascular mechanisms might be impaired and the PAR system is thought to be activated.

  2. Toll-like receptor 4 upregulation by angiotensin II contributes to hypertension and vascular dysfunction through reactive oxygen species production.

    PubMed

    De Batista, Priscila R; Palacios, Roberto; Martín, Angela; Hernanz, Raquel; Médici, Cindy T; Silva, Marito A S C; Rossi, Emilly M; Aguado, Andrea; Vassallo, Dalton V; Salaices, Mercedes; Alonso, María J

    2014-01-01

    Hypertension is considered as a low-grade inflammatory disease, with adaptive immunity being an important mediator of this pathology. TLR4 may have a role in the development of several cardiovascular diseases; however, little is known about its participation in hypertension. We aimed to investigate whether TLR4 activation due to increased activity of the renin-angiotensin system (RAS) contributes to hypertension and its associated endothelial dysfunction. For this, we used aortic segments from Wistar rats treated with a non-specific IgG (1 µg/day) and SHRs treated with losartan (15 mg/kg·day), the non-specific IgG or the neutralizing antibody anti-TLR4 (1 µg/day), as well as cultured vascular smooth muscle cells (VSMC) from Wistar and SHRs. TLR4 mRNA levels were greater in the VSMC and aortas from SHRs compared with Wistar rats; losartan treatment reduced those levels in the SHRs. Treatment of the SHRs with the anti-TLR4 antibody: 1) reduced the increased blood pressure, heart rate and phenylephrine-induced contraction while it improved the impaired acetylcholine-induced relaxation; 2) increased the potentiation of phenylephrine contraction after endothelium removal; and 3) abolished the inhibitory effects of tiron, apocynin and catalase on the phenylephrine-induced response as well as its enhancing effect of acetylcholine-induced relaxation. In SHR VSMCs, angiotensin II increased TLR4 mRNA levels, and losartan reduced that increase. CLI-095, a TLR4 inhibitor, mitigated the increases in NAD(P)H oxidase activity, superoxide anion production, migration and proliferation that were induced by angiotensin II. In conclusion, TLR4 pathway activation due to increased RAS activity is involved in hypertension, and by inducing oxidative stress, this pathway contributes to the endothelial dysfunction associated with this pathology. These results suggest that TLR4 and innate immunity may play a role in hypertension and its associated end-organ damage.

  3. NMDA receptor dysfunction contributes to impaired brain-derived neurotrophic factor-induced facilitation of hippocampal synaptic transmission in a Tau transgenic model.

    PubMed

    Burnouf, Sylvie; Martire, Alberto; Derisbourg, Maxime; Laurent, Cyril; Belarbi, Karim; Leboucher, Antoine; Fernandez-Gomez, Francisco J; Troquier, Laetitia; Eddarkaoui, Sabiha; Grosjean, Marie-Eve; Demeyer, Dominique; Muhr-Tailleux, Anne; Buisson, Alain; Sergeant, Nicolas; Hamdane, Malika; Humez, Sandrine; Popoli, Patrizia; Buée, Luc; Blum, David

    2013-02-01

    While the spatiotemporal development of Tau pathology has been correlated with occurrence of cognitive deficits in Alzheimer's patients, mechanisms underlying these deficits remain unclear. Both brain-derived neurotrophic factor (BDNF) and its tyrosine kinase receptor TrkB play a critical role in hippocampus-dependent synaptic plasticity and memory. When applied on hippocampal slices, BDNF is able to enhance AMPA receptor-dependent hippocampal basal synaptic transmission through a mechanism involving TrkB and N-methyl-d-Aspartate receptors (NMDAR). Using THY-Tau22 transgenic mice, we demonstrated that hippocampal Tau pathology is associated with loss of synaptic enhancement normally induced by exogenous BDNF. This defective response was concomitant to significant memory impairments. We show here that loss of BDNF response was due to impaired NMDAR function. Indeed, we observed a significant reduction of NMDA-induced field excitatory postsynaptic potential depression in the hippocampus of Tau mice together with a reduced phosphorylation of NR2B at the Y1472, known to be critical for NMDAR function. Interestingly, we found that both NR2B and Src, one of the NR2B main kinases, interact with Tau and are mislocalized to the insoluble protein fraction rich in pathological Tau species. Defective response to BDNF was thus likely related to abnormal interaction of Src and NR2B with Tau in THY-Tau22 animals. These are the first data demonstrating a relationship between Tau pathology and synaptic effects of BDNF and supporting a contribution of defective BDNF response and impaired NMDAR function to the cognitive deficits associated with Tauopathies.

  4. Tumor necrosis factor-alpha and its receptors contribute to apoptosis of oligodendrocytes in the spinal cord of spinal hyperostotic mouse (twy/twy) sustaining chronic mechanical compression.

    PubMed

    Inukai, Tomoo; Uchida, Kenzo; Nakajima, Hideaki; Yayama, Takafumi; Kobayashi, Shigeru; Mwaka, Erisa S; Guerrero, Alexander Rodriguez; Baba, Hisatoshi

    2009-12-15

    STUDY DESIGN.: To examine the distribution of apoptotic cells and expression of tumor necrosis factor (TNF)-alpha and its receptors in the spinal hyperostotic mouse (twy/twy) with chronic cord compression using immunohistochemical methods. OBJECTIVE.: To study the mechanisms of apoptosis, particularly in oligodendrocytes, which could contribute to degenerative change and demyelination in chronic mechanical cord compression. SUMMARY OF BACKGROUND DATA.: TNF-alpha acts as an external signal initiating apoptosis in neurons and oligodendrocytes after spinal cord injury. Chronic spinal cord compression caused neuronal loss, myelin destruction, and axonal degeneration. However, the biologic mechanisms of apoptosis in chronically compressed spinal cord remain unclear. METHODS.: The cervical spinal cord of 34 twy mice aged 20 to 24 weeks and 11 control animals were examined. The apoptotic cells were detected by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) staining. The expression and the localization of TNF-alpha, TNF receptor 1 (TNFR1), and TNF receptor 2 (TNFR2) were examined using immunoblot and immnohistochemical analysis. RESULTS.: The number of TUNEL-positive cells in the white matter increased with the severity of compression, which was further increased bilaterally in the white matter of twy/twy mice. Double immunofluorescence staining showed that the number of cells positive for TUNEL and RIP, a marker of oligodendrocytes, increased in the white matter with increased severity of cord compression. Immunoblot analysis demonstrated overexpression of TNF-alpha, TNFR1, and TNFR2 in severe compression. The expression of TNF-alpha appeared in local cells including microglia while that of TNFR1 and TNFR2 was noted in apoptotic oligodendrocytes. CONCLUSION.: Our results suggested that the proportion of apoptotic oligodendrocytes, causing spongy axonal degeneration and demyelination, correlated with the magnitude of cord

  5. Astrocyte-derived Adenosine and A1 Receptor Activity Contribute to Sleep Loss-Induced Deficits in Hippocampal Synaptic Plasticity and Memory in Mice

    PubMed Central

    Florian, Cédrick; Vecsey, Christopher G.; Halassa, Michael M.; Haydon, Philip G.; Abel, Ted

    2011-01-01

    Sleep deprivation (SD) can have a negative impact on cognitive function, but the mechanism(s) by which SD modulates memory remain unclear. We have previously shown that astrocyte-derived adenosine is a candidate molecule involved in the cognitive deficits following a brief period of SD (Halassa et al., 2009). In this study, we examined whether genetic disruption of SNARE-dependent exocytosis in astrocytes (dnSNARE mice) or pharmacological blockade of A1 receptor signaling using an adenosine A1 receptor (A1R) antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) could prevent the negative effects of 6 hours of SD on hippocampal late-phase long-term potentiation (L-LTP) and hippocampus-dependent spatial object recognition memory. We found that SD impaired L-LTP in wild-type mice but not in dnSNARE mice. Similarly, this deficit in L-LTP resulting from SD was prevented by a chronic infusion of CPT. Consistent with these results, we found that hippocampus-dependent memory deficits produced by SD were rescued in dnSNARE mice and CPT-treated mice. These data provide the first evidence that astrocytic ATP and adenosine A1R activity contribute to the effects of SD on hippocampal synaptic plasticity and hippocampus-dependent memory, and suggest a new therapeutic target to reverse the hippocampus-related cognitive deficits induced by sleep loss. PMID:21562257

  6. Glutamate receptor antagonist infusions into the basolateral and medial amygdala reveal differential contributions to olfactory vs. context fear conditioning and expression

    PubMed Central

    Walker, David L.; Paschall, Gayla Y.; Davis, Michael

    2005-01-01

    The basolateral amygdala's involvement in fear acquisition and expression to visual and auditory stimuli is well known. The involvement of the basolateral and other amygdala areas in fear acquisition and expression to stimuli of other modalities is less certain. We evaluated the contribution of the basolateral and medial amygdala to olfactory and to context fear and fear conditioning by infusing into these areas the NMDA receptor antagonist AP5, the AMPA/kainate receptor antagonist NBQX, or vehicle prior to either odor-shock pairings or fear-potentiated startle testing. Pre-training AP5 infusions into the basolateral amygdala disrupted fear conditioning to the odor but not the context conditioned stimulus (CS). Pre-test NBQX infusions disrupted fear-potentiated startle to the odor but not context CS. Neither compound blocked fear conditioning when infused into the medial amygdala prior to training, but pre-test NBQX infusions did block fear-potentiated startle. The results confirm and extend recent findings suggesting a role for the basolateral amygdala in olfactory fear and fear conditioning, reveal an unexpected dissociation of the basolateral amygdala's involvement in discrete cue versus context fear and fear conditioning, and implicate for the first time the medial amygdala in fear-potentiated startle. PMID:15774945

  7. The neurogenetics of nice: receptor genes for oxytocin and vasopressin interact with threat to predict prosocial behavior.

    PubMed

    Poulin, Michael J; Holman, E Alison; Buffone, Anneke

    2012-05-01

    Oxytocin, vasopressin, and their receptor genes influence prosocial behavior in the laboratory and in the context of close relationships. These peptides may also promote social engagement following threat. However, the scope of their prosocial effects is unknown. We examined oxytocin receptor (OXTR) polymorphism rs53576, as well as vasopressin receptor 1a (AVPR1a) polymorphisms rs1 and rs3 in a national sample of U.S. residents (n = 348). These polymorphisms interacted with perceived threat to predict engagement in volunteer work or charitable activities and commitment to civic duty. Specifically, greater perceived threat predicted engagement in fewer charitable activities for individuals with A/A and A/G genotypes of OXTR rs53576, but not for G/G individuals. Similarly, greater perceived threat predicted lower commitment to civic duty for individuals with one or two short alleles for AVPR1a rs1, but not for individuals with only long alleles. Oxytocin, vasopressin, and their receptor genes may significantly influence prosocial behavior and may lie at the core of the caregiving behavioral system.

  8. The Presence of Two Receptor-Binding Proteins Contributes to the Wide Host Range of Staphylococcal Twort-Like Phages

    PubMed Central

    Takeuchi, Ippei; Osada, Keita; Azam, Aa Haeruman; Asakawa, Hiroaki; Miyanaga, Kazuhiko

    2016-01-01

    ABSTRACT Thanks to their wide host range and virulence, staphylococcal bacteriophages (phages) belonging to the genus Twortlikevirus (staphylococcal Twort-like phages) are regarded as ideal candidates for clinical application for Staphylococcus aureus infections due to the emergence of antibiotic-resistant bacteria of this species. To increase the usability of these phages, it is necessary to understand the mechanism underlying host recognition, especially the receptor-binding proteins (RBPs) that determine host range. In this study, we found that the staphylococcal Twort-like phage ΦSA012 possesses at least two RBPs. Genomic analysis of five mutant phages of ΦSA012 revealed point mutations in orf103, in a region unique to staphylococcal Twort-like phages. Phages harboring mutated ORF103 could not infect S. aureus strains in which wall teichoic acids (WTAs) are glycosylated with α-N-acetylglucosamine (α-GlcNAc). A polyclonal antibody against ORF103 also inhibited infection by ΦSA012 in the presence of α-GlcNAc, suggesting that ORF103 binds to α-GlcNAc. In contrast, a polyclonal antibody against ORF105, a short tail fiber component previously shown to be an RBP, inhibited phage infection irrespective of the presence of α-GlcNAc. Immunoelectron microscopy indicated that ORF103 is a tail fiber component localized at the bottom of the baseplate. From these results, we conclude that ORF103 binds α-GlcNAc in WTAs, whereas ORF105, the primary RBP, is likely to bind the WTA backbone. These findings provide insight into the infection mechanism of staphylococcal Twort-like phages. IMPORTANCE Staphylococcus phages belonging to the genus Twortlikevirus (called staphylococcal Twort-like phages) are considered promising agents for control of Staphylococcus aureus due to their wide host range and highly lytic capabilities. Although staphylococcal Twort-like phages have been studied widely for therapeutic purposes, the host recognition process of staphylococcal Twort

  9. Different Contribution of Redox-Sensitive Transient Receptor Potential Channels to Acetaminophen-Induced Death of Human Hepatoma Cell Line

    PubMed Central

    Badr, Heba; Kozai, Daisuke; Sakaguchi, Reiko; Numata, Tomohiro; Mori, Yasuo

    2016-01-01

    Acetaminophen (APAP) is a safe analgesic antipyretic drug at prescribed doses. Its overdose, however, can cause life-threatening liver damage. Though, involvement of oxidative stress is widely acknowledged in APAP-induced hepatocellular death, the mechanism of this increased oxidative stress and the associated alterations in Ca2+ homeostasis are still unclear. Among members of transient receptor potential (TRP) channels activated in response to oxidative stress, we here identify that redox-sensitive TRPV1, TRPC1, TRPM2, and TRPM7 channels underlie Ca2+ entry and downstream cellular damages induced by APAP in human hepatoma (HepG2) cells. Our data indicate that APAP treatment of HepG2 cells resulted in increased reactive oxygen species (ROS) production, glutathione (GSH) depletion, and Ca2+ entry leading to increased apoptotic cell death. These responses were significantly suppressed by pretreatment with the ROS scavengers N-acetyl-L-cysteine (NAC) and 4,5-dihydroxy-1,3-benzene disulfonic acid disodium salt monohydrate (Tiron), and also by preincubation of cells with the glutathione inducer Dimethylfumarate (DMF). TRP subtype-targeted pharmacological blockers and siRNAs strategy revealed that suppression of either TRPV1, TRPC1, TRPM2, or TRPM7 reduced APAP-induced ROS formation, Ca2+ influx, and cell death; the effects of suppression of TRPV1 or TRPC1, known to be activated by oxidative cysteine modifications, were stronger than those of TRPM2 or TRPM7. Interestingly, TRPV1 and TRPC1 were labeled by the cysteine-selective modification reagent, 5,5′-dithiobis (2-nitrobenzoic acid)-2biotin (DTNB-2Bio), and this was attenuated by pretreatment with APAP, suggesting that APAP and/or its oxidized metabolites act directly on the modification target cysteine residues of TRPV1 and TRPC1 proteins. In human liver tissue, TRPV1, TRPC1, TRPM2, and TRPM7 channels transcripts were localized mainly to hepatocytes and Kupffer cells. Our findings strongly suggest that APAP

  10. Contribution of the Striatum to the Effects of 5-HT1A Receptor Stimulation in L-DOPA-treated Hemiparkinsonian Rats

    PubMed Central

    Bishop, Christopher; Krolewski, David M.; Eskow, Karen L.; Barnum, Christopher J.; Dupre, Kristin B.; Deak, Terrence; Walker, Paul D.

    2009-01-01

    Clinical and experimental studies implicate the use of serotonin (5-HT)1A receptor agonists for the reduction of l-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID). Although raphe nuclei likely play a role in these antidyskinetic effects, an unexplored population of striatal 5-HT1A receptors (5-HT1AR) may also contribute. To better characterize this mechanism, L-DOPA-primed hemiparkinsonian rats received the 5-HT1AR agonist ±8-OH-DPAT (0, 0.1, 1.0 mg/kg, i.p.) with or without cotreatment with the 5-HT1AR antagonist WAY100635 (0.5 mg/kg, i.p.) 5 min after L-DOPA, after which abnormal involuntary movements (AIMs), rotations, and forelimb akinesia were quantified. To establish the effects of 5-HT1AR stimulation on L-DOPA-induced c-fos and preprodynorphin (PPD) mRNA within the dopamine-depleted striatum, immunohistochemistry and real-time reverse transcription polymerase chain reaction, respectively, were used. Finally, to determine the contribution of striatal 5-HT1AR to these effects, L-DOPA-primed hemiparkinsonian rats received bilateral intrastriatal microinfusions of ±8-OH-DPAT (0, 5, or 10 μg/side), WAY100635 (5 μg/side), or both (10 μg + 5 μg/side) 5 min after L-DOPA, after which AIMs and rotations were examined. Systemic ±8-OH-DPAT dose- and receptor-dependently attenuated L-DOPA-mediated AIMs and improved forelimb akinesia. Striatal c-fos immuno-reactivity and PPD mRNA ipsilateral to the lesion were strongly induced by L-DOPA, while ±8-OH-DPAT suppressed these effects. Finally, intrastriatal infusions of ±8-OH-DPAT reduced AIMs while coinfusion of WAY100635 reversed its antidyskinetic effect. Collectively, these results support the hypothesis that the cellular and behavioral properties of 5-HT1AR agonists are conveyed in part via a population of functional 5-HT1AR within the striatum. PMID:19115412

  11. P2Y1 Receptor Signaling Contributes to High Salt-Induced Priming of the NLRP3 Inflammasome in Retinal Pigment Epithelial Cells

    PubMed Central

    Prager, Philipp; Hollborn, Margrit; Steffen, Anja; Wiedemann, Peter; Kohen, Leon; Bringmann, Andreas

    2016-01-01

    Background Systemic hypertension is a risk factor of age-related macular degeneration (AMD), a chronic inflammatory disease. Acute hypertension is caused by increased extracellular osmolarity after intake of dietary salt (NaCl). We determined in cultured human retinal pigment epithelial (RPE) cells whether high extracellular NaCl alters the gene expression of inflammasome-associated proteins, and whether autocrine/paracrine purinergic (P2) receptor signaling contributes to the NaCl-induced NLRP3 gene expression. Methodology/Principal Findings Hyperosmolarity was induced by the addition of 100 mM NaCl or sucrose to the culture medium. Gene and protein expression levels were determined with real-time RT-PCR and Western blot analysis, respectively. IL-1β and IL-18 levels were evaluated with ELISA. Nuclear factor of activated T cell 5 (NFAT5) expression was knocked down with siRNA. High extracellular NaCl induced NLRP3 and pro-IL-1β gene expression, while the gene expression of further inflammasome-associated proteins (NLRP1, NLRP2, NLRP6, NLRP7, NLRP12, NLRC4, AIM2, ASC, procaspase-1, pro-IL-18) was not altered or below the detection threshold. The NaCl-induced NLRP3 gene expression was partially dependent on the activities of phospholipase C, IP3 receptors, protein kinase C, the serum and glucocorticoid-regulated kinase, p38 MAPK, ERK1/2, JNK, PI3K, and the transcription factors HIF-1 and NFAT5. Pannexin-dependent ATP release and P2Y1 receptor activation is required for the full induction of NLRP3 gene expression. High NaCl induced a transient increase of the NLRP3 protein level and a moderate NLRP3 inflammasome activation, as indicated by the transient increase of the cytosolic level of mature IL-1β. High NaCl also induced secretion of IL-18. Conclusion High extracellular NaCl induces priming of the NLRP3 inflammasome in RPE cells, in part via P2Y1 receptor signaling. The inflammasome priming effect of NaCl suggests that high intake of dietary salt may promote

  12. Bovine Immunoinhibitory Receptors Contribute to Suppression of Mycobacterium avium subsp. paratuberculosis-Specific T-Cell Responses.

    PubMed

    Okagawa, Tomohiro; Konnai, Satoru; Nishimori, Asami; Ikebuchi, Ryoyo; Mizorogi, Seiko; Nagata, Reiko; Kawaji, Satoko; Tanaka, Shogo; Kagawa, Yumiko; Murata, Shiro; Mori, Yasuyuki; Ohashi, Kazuhiko

    2015-10-19

    Johne's disease (paratuberculosis) is a chronic enteritis in cattle that is caused by intracellular infection with Mycobacterium avium subsp. paratuberculosis. This infection is characterized by the functional exhaustion of T-cell responses to M. avium subsp. paratuberculosis antigens during late subclinical and clinical stages, presumably facilitating the persistence of this bacterium and the formation of clinical lesions. However, the mechanisms underlying T-cell exhaustion in Johne's disease are poorly understood. Thus, we performed expression and functional analyses of the immunoinhibitory molecules programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) and lymphocyte activation gene 3 (LAG-3)/major histocompatibility complex class II (MHC-II) in M. avium subsp. paratuberculosis-infected cattle during the late subclinical stage. Flow cytometric analyses revealed the upregulation of PD-1 and LAG-3 in T cells in infected animals, which suffered progressive suppression of interferon gamma (IFN-γ) responses to the M. avium subsp. paratuberculosis antigen. In addition, PD-L1 and MHC-II were expressed on macrophages from infected animals, consistent with PD-1 and LAG-3 pathways contributing to the suppression of IFN-γ responses during the subclinical stages of M. avium subsp. paratuberculosis infection. Furthermore, dual blockade of PD-L1 and LAG-3 enhanced M. avium subsp. paratuberculosis-specific IFN-γ responses in blood from infected animals, and in vitro LAG-3 blockade enhanced IFN-γ production from M. avium subsp. paratuberculosis-specific CD4(+) and CD8(+) T cells. Taken together, the present data indicate that M. avium subsp. paratuberculosis-specific T-cell exhaustion is in part mediated by PD-1/PD-L1 and LAG-3/MHC-II interactions and that LAG-3 is a molecular target for the control of M. avium subsp. paratuberculosis-specific T-cell responses.

  13. Bovine Immunoinhibitory Receptors Contribute to Suppression of Mycobacterium avium subsp. paratuberculosis-Specific T-Cell Responses

    PubMed Central

    Okagawa, Tomohiro; Konnai, Satoru; Nishimori, Asami; Ikebuchi, Ryoyo; Mizorogi, Seiko; Nagata, Reiko; Kawaji, Satoko; Tanaka, Shogo; Kagawa, Yumiko; Murata, Shiro; Mori, Yasuyuki

    2015-01-01

    Johne's disease (paratuberculosis) is a chronic enteritis in cattle that is caused by intracellular infection with Mycobacterium avium subsp. paratuberculosis. This infection is characterized by the functional exhaustion of T-cell responses to M. avium subsp. paratuberculosis antigens during late subclinical and clinical stages, presumably facilitating the persistence of this bacterium and the formation of clinical lesions. However, the mechanisms underlying T-cell exhaustion in Johne's disease are poorly understood. Thus, we performed expression and functional analyses of the immunoinhibitory molecules programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) and lymphocyte activation gene 3 (LAG-3)/major histocompatibility complex class II (MHC-II) in M. avium subsp. paratuberculosis-infected cattle during the late subclinical stage. Flow cytometric analyses revealed the upregulation of PD-1 and LAG-3 in T cells in infected animals, which suffered progressive suppression of interferon gamma (IFN-γ) responses to the M. avium subsp. paratuberculosis antigen. In addition, PD-L1 and MHC-II were expressed on macrophages from infected animals, consistent with PD-1 and LAG-3 pathways contributing to the suppression of IFN-γ responses during the subclinical stages of M. avium subsp. paratuberculosis infection. Furthermore, dual blockade of PD-L1 and LAG-3 enhanced M. avium subsp. paratuberculosis-specific IFN-γ responses in blood from infected animals, and in vitro LAG-3 blockade enhanced IFN-γ production from M. avium subsp. paratuberculosis-specific CD4+ and CD8+ T cells. Taken together, the present data indicate that M. avium subsp. paratuberculosis-specific T-cell exhaustion is in part mediated by PD-1/PD-L1 and LAG-3/MHC-II interactions and that LAG-3 is a molecular target for the control of M. avium subsp. paratuberculosis-specific T-cell responses. PMID:26483406

  14. An excessive increase in glutamate contributes to glucose-toxicity in β-cells via activation of pancreatic NMDA receptors in rodent diabetes

    PubMed Central

    Huang, Xiao-Ting; Li, Chen; Peng, Xiang-Ping; Guo, Jia; Yue, Shao-Jie; Liu, Wei; Zhao, Fei-Yan; Han, Jian-Zhong; Huang, Yan-Hong; Yang-Li, Y -L; Cheng, Qing-Mei; Zhou, Zhi-Guang; Chen, Chen; Feng, Dan-Dan; Luo, Zi-Qiang

    2017-01-01

    In the nervous system, excessive activation of NMDA receptors causes neuronal injury. Although activation of NMDARs has been proposed to contribute to the progress of diabetes, little is known about the effect of excessive long-term activation of NMDARs on β-cells, especially under the challenge of hyperglycemia. Here we thoroughly investigated whether endogenous glutamate aggravated β-cell dysfunction under chronic exposure to high-glucose via activation of NMDARs. The glutamate level was increased in plasma of diabetic mice or patients and in the supernatant of β-cell lines after treatment with high-glucose for 72 h. Decomposing the released glutamate improved GSIS of β-cells under chronic high-glucose exposure. Long-term treatment of β-cells with NMDA inhibited cell viability and decreased GSIS. These effects were eliminated by GluN1 knockout. The NMDAR antagonist MK-801 or GluN1 knockout prevented high-glucose-induced dysfunction in β-cells. MK-801 also decreased the expression of pro-inflammatory cytokines, and inhibited I-κB degradation, ROS generation and NLRP3 inflammasome expression in β-cells exposed to high-glucose. Furthermore, another NMDAR antagonist, Memantine, improved β-cells function in diabetic mice. Taken together, these findings indicate that an increase of glutamate may contribute to the development of diabetes through excessive activation of NMDARs in β-cells, accelerating β-cells dysfunction and apoptosis induced by hyperglycemia. PMID:28303894

  15. Fcγ and Complement Receptors and Complement Proteins in Neutrophil Activation in Rheumatoid Arthritis: Contribution to Pathogenesis and Progression and Modulation by Natural Products

    PubMed Central

    Paoliello-Paschoalato, Adriana Balbina; Marchi, Larissa Fávaro; de Andrade, Micássio Fernandes; Kabeya, Luciana Mariko; Donadi, Eduardo Antônio; Lucisano-Valim, Yara Maria

    2015-01-01

    Rheumatoid arthritis (RA) is a highly disabling disease that affects all structures of the joint and significantly impacts on morbidity and mortality in RA patients. RA is characterized by persistent inflammation of the synovial membrane lining the joint associated with infiltration of immune cells. Eighty to 90% of the leukocytes infiltrating the synovia are neutrophils. The specific role that neutrophils play in the onset of RA is not clear, but recent studies have evidenced that they have an important participation in joint damage and disease progression through the release of proteolytic enzymes, reactive oxygen species (ROS), cytokines, and neutrophil extracellular traps, in particular during frustrated phagocytosis of immune complexes (ICs). In addition, the local and systemic activation of the complement system contributes to the pathogenesis of RA and other IC-mediated diseases. This review discusses (i) the participation of Fcγ and complement receptors in mediating the effector functions of neutrophils in RA; (ii) the contribution of the complement system and ROS-dependent and ROS-independent mechanisms to joint damage in RA; and (iii) the use of plant extracts, dietary compounds, and isolated natural compounds in the treatment of RA, focusing on modulation of the effector functions of neutrophils and the complement system activity and/or activation. PMID:26346244

  16. Contribution of Toll-like receptors to the control of hepatitis B virus infection by initiating antiviral innate responses and promoting specific adaptive immune responses

    PubMed Central

    Ma, Zhiyong; Zhang, Ejuan; Yang, Dongliang; Lu, Mengji

    2015-01-01

    It is well accepted that adaptive immunity plays a key role in the control of hepatitis B virus (HBV) infection. In contrast, the contribution of innate immunity has only received attention in recent years. Toll-like receptors (TLRs) sense pathogen-associated molecule patterns and activate antiviral mechanisms, including intracellular antiviral pathways and the production of antiviral effector interferons (IFNs) and pro-inflammatory cytokines. Experimental results from in vitro and in vivo models have demonstrated that TLRs mediate the activation of cellular signaling pathways and the production of antiviral cytokines, resulting in a suppression of HBV replication. However, HBV infection is associated with downregulation of TLR expression on host cells and blockade of the activation of downstream signaling pathways. In primary HBV infection, TLRs may slow down HBV infection, but contribute only indirectly to viral clearance. Importantly, TLRs may modulate HBV-specific T- and B-cell responses in vivo, which are essential for the termination of HBV infection. Thus, TLR agonists are promising candidates to act as immunomodulators for the treatment of chronic HBV infection. Antiviral treatment may recover TLR expression and function in chronic HBV infection and may increase the efficacy of therapeutic approaches based on TLR activation. A combined therapeutic strategy with antiviral treatment and TLR activation could facilitate the restoration of HBV-specific immune responses and thereby, achieve viral clearance in chronically infected HBV patients. PMID:25418467

  17. Design, Synthesis, and Structure–Activity Relationship Studies of a Series of [4-(4-Carboxamidobutyl)]-1-arylpiperazines: Insights into Structural Features Contributing to Dopamine D3 versus D2 Receptor Subtype Selectivity

    PubMed Central

    2015-01-01

    Antagonist and partial agonist modulators of the dopamine D3 receptor (D3R) have emerged as promising therapeutics for the treatment of substance abuse and neuropsychiatric disorders. However, development of druglike lead compounds with selectivity for the D3 receptor has been challenging because of the high sequence homology between the D3R and the dopamine D2 receptor (D2R). In this effort, we synthesized a series of acylaminobutylpiperazines incorporating aza-aromatic units and evaluated their binding and functional activities at the D3 and D2 receptors. Docking studies and results from evaluations against a set of chimeric and mutant receptors suggest that interactions at the extracellular end of TM7 contribute to the D3R versus D2R selectivity of these ligands. Molecular insights from this study could potentially enable rational design of potent and selective D3R ligands. PMID:25126833

  18. Prolactin regulates TRPV1, TRPA1, and TRPM8 in sensory neurons in a sex-dependent manner: Contribution of prolactin receptor to inflammatory pain.

    PubMed

    Patil, Mayur J; Ruparel, Shivani B; Henry, Michael A; Akopian, Armen N

    2013-11-01

    Prolactin (PRL) is a hormone produced in the anterior pituitary but also synthesized extrapituitary where it can influence diverse cellular processes, including inflammatory responses. Females experience greater pain in certain inflammatory conditions, but the contribution of the PRL system to sex-dependent inflammatory pain is unknown. We found that PRL regulates transient receptor potential (TRP) channels in a sex-dependent manner in sensory neurons. At >20 ng/ml, PRL sensitizes TRPV1 in female, but not male, neurons. This effect is mediated by PRL receptor (PRL-R). Likewise, TRPA1 and TRPM8 were sensitized by 100 ng/ml PRL only in female neurons. We showed that complete Freund adjuvant (CFA) upregulated PRL levels in the inflamed paw of both male and female rats, but levels were higher in females. In contrast, CFA did not change mRNA levels of long and short PRL-R in the dorsal root ganglion or spinal cord. Analysis of PRL and PRL-R knockout (KO) mice demonstrated that basal responses to cold stimuli were only altered in females, and with no significant effects on heat and mechanical responses in both sexes. CFA-induced heat and cold hyperalgesia were not changed in PRL and PRL-R KO compared with wild-type (WT) males, whereas significant reduction of heat and cold post-CFA hyperalgesia was detected in PRL and PRL-R KO females. Attenuation of CFA-induced mechanical allodynia was observed in both PRL and PRL-R KO females and males. Thermal hyperalgesia in PRL KO females was restored by administration of PRL into hindpaws. Overall, we demonstrate a sex-dependent regulation of peripheral inflammatory hyperalgesia by the PRL system.

  19. At Immature Mossy Fibers-CA3 Connections, Activation of Presynaptic GABAB Receptors by Endogenously Released GABA Contributes to Synapses Silencing

    PubMed Central

    Safiulina, Victoria F.; Cherubini, Enrico

    2008-01-01

    Early in postnatal life correlated GABAergic activity in the hippocampus is thought to play a crucial role in synaptogenesis and in the development of adult neuronal networks. Unlike adulthood, at this developmental stage, mossy fibers (MF) which are the axons of granule cells, release GABA into CA3 principal cells and interneurons. Here, we tested the hypothesis that at MF-CA3 connections, tonic activation of GABAB autoreceptors by GABA is responsible for the low probability of release and synapse silencing. Blocking GABAB receptors with CGP55845 enhanced the probability of GABA release and switched on silent synapses while the opposite was observed with baclofen. Both these effects were presynaptic and were associated with changes in paired-pulse ratio and coefficient of variation. In addition, enhancing the extracellular GABA concentration by repetitive stimulation of MF or by blocking the GABA transporter GAT-1, switched off active synapses, an effect that was prevented by CGP55845. In the presence of CGP55845, stimulation of MF-induced synaptic potentiation. The shift of EGABA from the depolarizing to the hyperpolarizing direction with bumetanide, a blocker of the cation-chloride co-transporter NKCC1, prevented synaptic potentiation and caused synaptic depression, suggesting that the depolarizing action of GABA observed in the presence of CGP55845 is responsible for the potentiating effect. It is proposed that, activation of GABAB receptors by spillover of GABA from MF terminals reduces the probability of release and contributes to synapses silencing. This would act as a filter to prevent excessive activation of the auto-associative CA3 network and the emergence of seizures. PMID:19277216

  20. Contribution of Fcγ receptors to human respiratory syncytial virus pathogenesis and the impairment of T-cell activation by dendritic cells.

    PubMed

    Gómez, Roberto S; Ramirez, Bruno A; Céspedes, Pablo F; Cautivo, Kelly M; Riquelme, Sebastián A; Prado, Carolina E; González, Pablo A; Kalergis, Alexis M

    2016-01-01

    Human respiratory syncytial virus (hRSV) is the leading cause of infant hospitalization related to respiratory disease. Infection with hRSV produces abundant infiltration of immune cells into the airways, which combined with an exacerbated pro-inflammatory immune response can lead to significant damage to the lungs. Human RSV re-infection is extremely frequent, suggesting that this virus may have evolved molecular mechanisms that interfere with host adaptive immunity. Infection with hRSV can be reduced by administering a humanized neutralizing antibody against the virus fusion protein in high-risk infants. Although neutralizing antibodies against hRSV effectively block the infection of airway epithelial cells, here we show that both, bone marrow-derived dendritic cells (DCs) and lung DCs undergo infection with IgG-coated virus (hRSV-IC), albeit abortive. Yet, this is enough to negatively modulate DC function. We observed that such a process is mediated by Fcγ receptors (FcγRs) expressed on the surface of DCs. Remarkably, we also observed that in the absence of hRSV-specific antibodies FcγRIII knockout mice displayed significantly less cellular infiltration in the lungs after hRSV infection, compared with wild-type mice, suggesting a potentially harmful, IgG-independent role for this receptor in hRSV disease. Our findings support the notion that FcγRs can contribute significantly to the modulation of DC function by hRSV and hRSV-IC. Further, we provide evidence for an involvement of FcγRIII in the development of hRSV pathogenesis.

  1. Coexpression of platelet-derived growth factor (PDGF) and PDGF-receptor genes by primary human astrocytomas may contribute to their development and maintenance.

    PubMed Central

    Maxwell, M; Naber, S P; Wolfe, H J; Galanopoulos, T; Hedley-Whyte, E T; Black, P M; Antoniades, H N

    1990-01-01

    The present studies investigated the expression of the two PDGF genes (c-sis/PDGF-2 and PDGF-1) and the PDGF-receptor b gene (PDGF-R) in 34 primary human astrocytomas. Northern blot analysis demonstrated the coexpression of the c-sis/PDGF-2 protooncogene and the PDGF-R gene in all astrocytomas examined. The majority of the tumors also expressed the PDGF-1 gene. There was no correlation between the expression of the two PDGF genes. Nonmalignant human brain tissue expressed the PDGF-R and PDGF-1 genes but not the c-sis/PDGF-2 protooncogene. In situ hybridization of astrocytoma tissue localized the expression of the c-sis and PDGF-R mRNA's in tumor cells. Capillary endothelial cells also expressed c-sis mRNA. In contrast, nonmalignant human brain tissue expressed only PDGF-R mRNA but not c-sis/PDGF-2 mRNA. The coexpression of a potent mitogenic growth factor protooncogene (c-sis) and its receptor gene in astrocytoma tumor cells suggests the presence of an autocrine mechanism that may contribute to the development and maintenance of astrocytomas. The expression of c-sis mRNA in tumor cells but not in nonmalignant brain cells may serve as an additional diagnostic criterion for the detection of astrocytomas in small tissue specimen using in situ hybridization for the detection of c-sis mRNA and/or immunostaining for the recognition of its protein product. Images PMID:2164040

  2. At immature mossy fibers-CA3 connections, activation of presynaptic GABA(B) receptors by endogenously released GABA contributes to synapses silencing.

    PubMed

    Safiulina, Victoria F; Cherubini, Enrico

    2009-01-01

    Early in postnatal life correlated GABAergic activity in the hippocampus is thought to play a crucial role in synaptogenesis and in the development of adult neuronal networks. Unlike adulthood, at this developmental stage, mossy fibers (MF) which are the axons of granule cells, release GABA into CA3 principal cells and interneurons. Here, we tested the hypothesis that at MF-CA3 connections, tonic activation of GABA(B) autoreceptors by GABA is responsible for the low probability of release and synapse silencing. Blocking GABA(B) receptors with CGP55845 enhanced the probability of GABA release and switched on silent synapses while the opposite was observed with baclofen. Both these effects were presynaptic and were associated with changes in paired-pulse ratio and coefficient of variation. In addition, enhancing the extracellular GABA concentration by repetitive stimulation of MF or by blocking the GABA transporter GAT-1, switched off active synapses, an effect that was prevented by CGP55845. In the presence of CGP55845, stimulation of MF-induced synaptic potentiation. The shift of E(GABA) from the depolarizing to the hyperpolarizing direction with bumetanide, a blocker of the cation-chloride co-transporter NKCC1, prevented synaptic potentiation and caused synaptic depression, suggesting that the depolarizing action of GABA observed in the presence of CGP55845 is responsible for the potentiating effect. It is proposed that, activation of GABA(B) receptors by spillover of GABA from MF terminals reduces the probability of release and contributes to synapses silencing. This would act as a filter to prevent excessive activation of the auto-associative CA3 network and the emergence of seizures.

  3. Differential contribution of the NR1- and NR2A-subunits to the selectivity filter of recombinant NMDA receptor channels.

    PubMed Central

    Wollmuth, L P; Kuner, T; Seeburg, P H; Sakmann, B

    1996-01-01

    pore size. 7. The cross-sectional diameter of the narrow constriction in wild-type NMDA receptor channels was estimated to be 0.55 nm. The pore sizes of the NR1(N598G)-NR2A and NR1-NR2A(N596G) mutant channels increased to approximately 0.75 and 0.67 nm, respectively. The double mutation, NR1(N598G)-NR2A(596G), increased the pore size to approximately 0.87 nm, essentially the sum of the increase produced by the individual mutations. 8. It is concluded that both the NR1- and NR2A-subunits contribute to the narrow constriction of NMDA receptor channels with asparagines located at non-homologous positions. The major determinants of the narrow constriction in NMDA receptor channels are the NR1 N-site asparagine and an asparagine adjacent to the NR2A N-site. Images Figure 2 PMID:8815211

  4. Biotransformation of a novel positive allosteric modulator of metabotropic glutamate receptor subtype 5 contributes to seizure-like adverse events in rats involving a receptor agonism-dependent mechanism.

    PubMed

    Bridges, Thomas M; Rook, Jerri M; Noetzel, Meredith J; Morrison, Ryan D; Zhou, Ya; Gogliotti, Rocco D; Vinson, Paige N; Xiang, Zixiu; Jones, Carrie K; Niswender, Colleen M; Lindsley, Craig W; Stauffer, Shaun R; Conn, P Jeffrey; Daniels, J Scott

    2013-09-01

    Activation of metabotropic glutamate receptor subtype 5 (mGlu5) represents a novel strategy for therapeutic intervention into multiple central nervous system disorders, including schizophrenia. Recently, a number of positive allosteric modulators (PAMs) of mGlu5 were discovered to exhibit in vivo efficacy in rodent models of psychosis, including PAMs possessing varying degrees of agonist activity (ago-PAMs), as well as PAMs devoid of agonist activity. However, previous studies revealed that ago-PAMs can induce seizure activity and behavioral convulsions, whereas pure mGlu5 PAMs do not induce these adverse effects. We recently identified a potent and selective mGlu5 PAM, VU0403602, that was efficacious in reversing amphetamine-induced hyperlocomotion in rats. The compound also induced time-dependent seizure activity that was blocked by coadministration of the mGlu5 antagonist, 2-methyl-6-(phenylethynyl) pyridine. Consistent with potential adverse effects induced by ago-PAMs, we found that VU0403602 had significant allosteric agonist activity. Interestingly, inhibition of VU0403602 metabolism in vivo by a pan cytochrome P450 (P450) inactivator completely protected rats from induction of seizures. P450-mediated biotransformation of VU0403602 was discovered to produce another potent ago-PAM metabolite-ligand (M1) of mGlu5. Electrophysiological studies in rat hippocampal slices confirmed agonist activity of both M1 and VU0403602 and revealed that M1 can induce epileptiform activity in a manner consistent with its proconvulsant behavioral effects. Furthermore, unbound brain exposure of M1 was similar to that of the parent compound, VU0403602. These findings indicate that biotransformation of mGlu5 PAMs to active metabolite-ligands may contribute to the epileptogenesis observed after in vivo administration of this class of allosteric receptor modulators.

  5. Colon OCTN2 Gene Expression Is Up-regulated by Peroxisome Proliferator-activated Receptor γ in Humans and Mice and Contributes to Local and Systemic Carnitine Homeostasis

    PubMed Central

    D'Argenio, Giuseppe; Petillo, Orsolina; Margarucci, Sabrina; Torpedine, Angela; Calarco, Anna; Koverech, Angela; Boccia, Angelo; Paolella, Giovanni; Peluso, Gianfranco

    2010-01-01

    In the large intestine organic cation transporter type-2 (OCTN2) is recognized as a transporter of compounds such as carnitine and colony sporulation factor, promoting health of the colon intestinal epithelium. Recent reports suggest that OCTN2 expression in small intestine is under control of peroxisome proliferator-activated receptor-α (PPARα). However, PPARα contribution to colonic OCTN2 expression remains controversial. Here we examined the transcriptional regulation of colon OCTN2 gene by PPARγ. To exclude any additional modulation of other PPAR to OCTN2 expression, we used both in vivo and in vitro PPAR-null models and specific PPAR inhibitors. The PPARγ agonists thiazolidinediones increased both OCTN2 mRNA and protein expression in colonic epithelial cell lines independently by PPARα expression. The induction was blocked only by PPARγ antagonists or by γORF4, a PPARγ isoform with dominant negative activity, suggesting a PPARγ-dependent mechanism. A conserved noncanonical PPAR-responsive element was found by computational analysis in the first intron of human OCTN2 gene and validated by EMSA assay. Promoter-reporter assays further confirmed transcriptional functionality of the putative PPAR response element, whereas selective mutation caused complete loss of responsiveness to PPARγ activation. Finally, adenovirus-mediated overexpression of constitutively active PPARγ mutant increased colon OCTN2 expression in PPARα−/− mice. Interestingly, animals overexpressing colon PPARγ showed a significant increase in plasma carnitine, thus demonstrating the functional contribution of large intestine to systemic carnitine homeostasis. This study reveals a PPARγ-dependent absorption machinery in colon that is likely involved in the health of colon epithelium, in the microbiota-host interactions and in the absorption of nutraceuticals and drugs. PMID:20558736

  6. Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan area, Hanoi-Vietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment.

    PubMed

    Tuyen, Le Huu; Tue, Nguyen Minh; Suzuki, Go; Misaki, Kentaro; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke

    2014-09-01

    Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (Σ24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 μg/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 μg/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed <0.1% to CALUX-TEQs for both rural and urban sites. These results suggest TEQ contribution of other aryl hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach.

  7. The Subcellular Dynamics of the Gs-Linked Receptor GPR3 Contribute to the Local Activation of PKA in Cerebellar Granular Neurons

    PubMed Central

    Miyagi, Tatsuhiro; Tanaka, Shigeru; Hide, Izumi; Shirafuji, Toshihiko; Sakai, Norio

    2016-01-01

    G-protein-coupled receptor (GPR) 3 is a member of the GPR family that constitutively activates adenylate cyclase. We have reported that the expression of GPR3 in cerebellar granular neurons (CGNs) contributes to neurite outgrowth and modulates neuronal proliferation and survival. To further identify its role, we have analyzed the precise distribution and local functions of GPR3 in neurons. The fluorescently tagged GPR3 protein was distributed in the plasma membrane, the Golgi body, and the endosomes. In addition, we have revealed that the plasma membrane expression of GPR3 functionally up-regulated the levels of PKA, as measured by a PKA FRET indicator. Next, we asked if the PKA activity was modulated by the expression of GPR3 in CGNs. PKA activity was highly modulated at the neurite tips compared to the soma. In addition, the PKA activity at the neurite tips was up-regulated when GPR3 was transfected into the cells. However, local PKA activity was decreased when endogenous GPR3 was suppressed by a GPR3 siRNA. Finally, we determined the local dynamics of GPR3 in CGNs using time-lapse analysis. Surprisingly, the fluorescent GPR3 puncta were transported along the neurite in both directions over time. In addition, the anterograde movements of the GPR3 puncta in the neurite were significantly inhibited by actin or microtubule polymerization inhibitors and were also disturbed by the Myosin II inhibitor blebbistatin. Moreover, the PKA activity at the tips of the neurites was decreased when blebbistatin was administered. These results suggested that GPR3 was transported along the neurite and contributed to the local activation of PKA in CGN development. The local dynamics of GPR3 in CGNs may affect local neuronal functions, including neuronal differentiation and maturation. PMID:26800526

  8. Evaluation of the ecotoxicity of sediments from Yangtze river estuary and contribution of priority PAHs to ah receptor--mediated activities.

    PubMed

    Liu, Li; Chen, Ling; Shao, Ying; Zhang, Lili; Floehr, Tilman; Xiao, Hongxia; Yan, Yan; Eichbaum, Kathrin; Hollert, Henner; Wu, Lingling

    2014-01-01

    In this study, in vitro bioassays were performed to assess the ecotoxicological potential of sediments from Yangtze River estuary. The cytotoxicity and aryl hydrocarbon receptor (AhR)-mediated toxicity of sediment extracts with rainbow trout (Oncorhynchus mykiss) liver cells were determined by neutral red retention and 7-ethoxyresorufin-O-deethylase assays. The cytotoxicity and AhR-mediated activity of sediments from the Yangtze River estuary ranged from low level to moderate level compared with the ecotoxicity of sediments from other river systems. However, Yangtze River releases approximately 14 times greater water discharge compared with Rhine, a major river in Europe. Thus, the absolute pollution mass transfer of Yangtze River may be detrimental to the environmental quality of estuary and East China Sea. Effect-directed analysis was applied to identify substances causing high dioxin-like activities. To identify unknown substances contributing to dioxin-like potencies of whole extracts, we fractionated crude extracts by open column chromatography. Non-polar paraffinic components (F1), weakly and moderately polar components (F2), and highly polar substances (F3) were separated from each crude extract of sediments. F2 showed the highest dioxin-like activities. Based on the results of mass balance calculation of chemical toxic equivalent concentrations (TEQs), our conclusion is that priority polycyclic aromatic hydrocarbons indicated a low portion of bio-TEQs ranging from 1% to 10% of crude extracts. Further studies should be conducted to identify unknown pollutants.

  9. A1 adenosine receptor-mediated GIRK channels contribute to the resting conductance of CA1 neurons in the dorsal hippocampus

    PubMed Central

    Kim, Chung Sub

    2015-01-01

    The dorsal and ventral hippocampi are functionally and anatomically distinct. Recently, we reported that dorsal Cornu Ammonis area 1 (CA1) neurons have a more hyperpolarized resting membrane potential and a lower input resistance and fire fewer action potentials for a given current injection than ventral CA1 neurons. Differences in the hyperpolarization-activated cyclic nucleotide-gated cation conductance between dorsal and ventral neurons have been reported, but these differences cannot fully account for the different resting properties of these neurons. Here, we show that coupling of A1 adenosine receptors (A1ARs) to G-protein-coupled inwardly rectifying potassium (GIRK) conductance contributes to the intrinsic membrane properties of dorsal CA1 neurons but not ventral CA1 neurons. The block of GIRKs with either barium or the more specific blocker Tertiapin-Q revealed that there is more resting GIRK conductance in dorsal CA1 neurons compared with ventral CA1 neurons. We found that the higher resting GIRK conductance in dorsal CA1 neurons was mediated by tonic A1AR activation. These results demonstrate that the different resting membrane properties between dorsal and ventral CA1 neurons are due, in part, to higher A1AR-mediated GIRK activity in dorsal CA1 neurons. PMID:25652929

  10. ATP6AP2/(Pro)renin Receptor Contributes to Glucose Metabolism via Stabilizing the Pyruvate Dehydrogenase E1 β Subunit*

    PubMed Central

    Kanda, Atsuhiro; Noda, Kousuke; Ishida, Susumu

    2015-01-01

    Aerobic glucose metabolism is indispensable for metabolically active cells; however, the regulatory mechanism of efficient energy generation in the highly evolved mammalian retina remains incompletely understood. Here, we revealed an unsuspected role for (pro)renin receptor, also known as ATP6AP2, in energy metabolism. Immunoprecipitation and mass spectrometry analyses identified the pyruvate dehydrogenase (PDH) complex as Atp6ap2-interacting proteins in the mouse retina. Yeast two-hybrid assays demonstrated direct molecular binding between ATP6AP2 and the PDH E1 β subunit (PDHB). Pdhb immunoreactivity co-localized with Atp6ap2 in multiple retinal layers including the retinal pigment epithelium (RPE). ATP6AP2 knockdown in RPE cells reduced PDH activity, showing a predilection to anaerobic glycolysis. ATP6AP2 protected PDHB from phosphorylation, thus controlling its protein stability. Down-regulated PDH activity due to ATP6AP2 knockdown inhibited glucose-stimulated oxidative stress in RPE cells. Our present data unraveled the novel function of ATP6AP2/(P)RR as a PDHB stabilizer, contributing to aerobic glucose metabolism together with oxidative stress. PMID:25720494

  11. Increased toll-like receptor 4 in cerebral endothelial cells contributes to the astrocyte swelling and brain edema in acute hepatic encephalopathy.

    PubMed

    Jayakumar, Arumugam R; Tong, Xiao Y; Curtis, Kevin M; Ruiz-Cordero, Roberto; Abreu, Maria T; Norenberg, Michael D

    2014-03-01

    Astrocyte swelling and the subsequent increase in intracranial pressure and brain herniation are major clinical consequences in patients with acute hepatic encephalopathy. We recently reported that conditioned media from brain endothelial cells (ECs) exposed to ammonia, a mixture of cytokines (CKs) or lipopolysaccharide (LPS), when added to astrocytes caused cell swelling. In this study, we investigated the possibility that ammonia and inflammatory agents activate the toll-like receptor 4 (TLR4) in ECs, resulting in the release of factors that ultimately cause astrocyte swelling. We found a significant increase in TLR4 protein expression when ECs were exposed to ammonia, CKs or LPS alone, while exposure of ECs to a combination of these agents potentiate such effects. In addition, astrocytes exposed to conditioned media from TLR4-silenced ECs that were treated with ammonia, CKs or LPS, resulted in a significant reduction in astrocyte swelling. TLR4 protein up-regulation was also detected in rat brain ECs after treatment with the liver toxin thioacetamide, and that thioacetamide-treated TLR4 knock-out mice exhibited a reduction in brain edema. These studies strongly suggest that ECs significantly contribute to the astrocyte swelling/brain edema in acute hepatic encephalopathy, likely as a consequence of increased TLR4 protein expression by blood-borne noxious agents.

  12. Molecular characterization of oxytocin receptor gene in water buffalo (Bubalus bubalis).

    PubMed

    Arunmozhi, N; Singh, S K; Sarath, T; Agarwal, S K; Doiphode, A; Shankar, U

    2014-10-01

    Buffaloes are known for their productivity as compared to average yielding cows due to higher fat percentage, better feed conversion ability and disease resistance. On the other hand, the reproductive performances of buffaloes are often considered as poor owing to late sexual maturity, weak/silent oestrus, repeat breeder and prolonged intercalving interval. The study of cascade of events during oestrus and oestrous cycle can be useful for the improvement of reproductive efficiency of buffaloes. More precisely, the hormonal changes initiated at the molecular level within the animal determine the reproductive nature of the species. Nucleotide/protein sequence analysis serves as a vital tool in analysing the binding of the hormones for their effect or functions. In this study, we have reported cloning and characterization of the complete coding (cDNA) sequence of oxytocin receptor gene (OXTR) in buffaloes. Buffalo OXTR gene contains an uninterrupted ORF of 1176 nucleotides corresponding to an inferred polypeptide length of 391 amino acids (aa). The molecular weight of the deduced aa sequence was found to be 43 kDa with an isoelectric point of 9.253 and 16.328 charge at pH 7.0. The deduced protein sequence consists of 38 strongly basic (+) (K,R), 22 strongly acidic (-) (D,E), 186 hydrophobic (A, I, L, F, W, V) and 95 Polar (N, C, Q, S, T, Y) aa. Results indicated that aspartate (D) at aa position 85 and D, R and C at aa positions 136, 137 and 138, respectively, are conserved in buffaloes. The buffalo OXTR gene shared a per cent similarity ranging from 84.7 to 98.1 and 88.5 to 97.7 at nucleotide and deduced aa sequence levels, respectively, with that of other species. Phylogram constructed on the basis of either nucleotide or deduced aa sequences of buffalo OXTR gene showed that buffalo, cattle and sheep have diverged from human and swine and formed a separate clad. The buffalo sequence has shown maximum similarity and closeness with cattle followed by sheep both at

  13. Activation of NOX2 by the stimulation of ionotropic and metabotropic glutamate receptors contributes to glutamate neurotoxicity in vivo through the production of reactive oxygen species and calpain activation.

    PubMed

    Guemez-Gamboa, Alicia; Estrada-Sánchez, Ana María; Montiel, Teresa; Páramo, Blanca; Massieu, Lourdes; Morán, Julio

    2011-11-01

    Prolonged activation of glutamate receptors leads to excitotoxicity. Several processes such as reactive oxygen species (ROS) production and activation of the calcium-dependent protease, calpain, contribute to glutamate-induced damage. It has been suggested that the ROS-producing enzyme, NADPH oxidase (NOX), plays a role in excitotoxicity. Studies have reported NOX activation after NMDA receptor stimulation during excitotoxic damage, but the role of non-NMDA and metabotropic receptors is unknown. We evaluated the roles of different glutamate receptor subtypes on NOX activation and neuronal death induced by the intrastriatal administration of glutamate in mice. In wild-type mice, NOX2 immunoreactivity in neurons and microglia was stimulated by glutamate administration, and it progressively increased as microglia became activated; calpain activity was also induced. By contrast, mice lacking NOX2 were less vulnerable to excitotoxicity, and there was reduced ROS production and protein nitrosylation, microglial reactivity, and calpain activation. These results suggest that NOX2 is stimulated by glutamate in neurons and reactive microglia through the activation of ionotropic and metabotropic receptors. Neuronal damage involves ROS production by NOX2, which, in turn, contributes to calpain activation.

  14. Contribution of Dopamine D1/5 Receptor Modulation of Post-Spike/Burst Afterhyperpolarization to Enhance Neuronal Excitability of Layer V Pyramidal Neurons in Prepubertal Rat Prefrontal Cortex

    PubMed Central

    Yi, Feng; Zhang, Xue-Han; Yang, Charles R.; Li, Bao-ming

    2013-01-01

    Dopamine (DA) receptors in the prefrontal cortex (PFC) modulate both synaptic and intrinsic plasticity that may contribute to cognitive processing. However, the ionic basis underlying DA actions to enhance neuronal plasticity in PFC remains ill-defined. Using whole-cell patch-clamp recordings in layer V-VI pyramidal cells in prepubertal rat PFC, we showed that DA, via activation of D1/5, but not D2/3/4, receptors suppress a Ca2+-dependent, apamin-sensitive K+ channel that mediates post-spike/burst afterhyperpolarization (AHP) to enhance neuronal excitability of PFC neurons. This inhibition is not dependent on HCN channels. The D1/5 receptor activation also enhanced an afterdepolarizing potential (ADP) that follows the AHP. Additional single-spike analyses revealed that DA or D1/5 receptor activation suppressed the apamin-sensitive post-spike mAHP, further contributing to the increase in evoked spike firing to enhance the neuronal excitability. Taken together, the D1/5 receptor modulates intrinsic mechanisms that amplify a long depolarizing input to sustain spike firing outputs in pyramidal PFC neurons. PMID:23977170

  15. Oxytocin Receptor Gene Variant Interacts with Intervention Delivery Format in Predicting Intervention Outcomes for Youth with Conduct Problems.

    PubMed

    Glenn, Andrea L; Lochman, John E; Dishion, Thomas; Powell, Nicole P; Boxmeyer, Caroline; Qu, Lixin

    2017-03-16

    Coping Power is an evidence-based preventive intervention program for youth with aggressive behavior problems that has traditionally been delivered in small group formats. Because of concerns about iatrogenic effects secondary to aggregation of high risk youth, the current study examined whether genetic risk may moderate intervention outcome when youth were randomly assigned to group versus individual formats of an intervention. The oxytocin receptor gene (OXTR) has been associated with social behavior and may influence susceptibility to social reinforcement in general and deviant peer influence in particular. One variant of OXTR (rs2268493) was examined in 197 fourth-grade African-American children (64% male) who were randomly assigned to Group Coping Power or Individual Coping Power (Lochman et al. 2015). Longitudinal assessments of teacher- and parent-reported behavior were collected through a 1-year follow-up. Growth curve analyses revealed a genotype by delivery format interaction. Youth with the A/A genotype demonstrated reductions in externalizing problems over the course of the intervention regardless of intervention format. In contrast, carriers of the G allele receiving the group-based intervention showed little improvement during the intervention and a worsening of symptoms during the follow-up year, while those receiving the individual format demonstrated reductions in externalizing problems. Given the associations between this OXTR variant and social bonding, carriers of the G allele may be more sensitive to social rewards from deviant peers in the group setting. This study suggests that genetic factors may be useful in predicting which type of intervention will be most effective for a particular individual.

  16. Angiotensin II type 1a receptors in subfornical organ contribute towards chronic intermittent hypoxia-associated sustained increase in mean arterial pressure.

    PubMed

    Saxena, Ashwini; Little, Joel T; Nedungadi, T Prashant; Cunningham, J Thomas

    2015-03-01

    Sleep apnea is associated with hypertension. The mechanisms contributing to a sustained increase in mean arterial pressure (MAP) even during normoxic awake-state remain unknown. Rats exposed to chronic intermittent hypoxia for 7 days, a model of the hypoxemia associated with sleep apnea, exhibit sustained increases in MAP even during the normoxic dark phase. Activation of the renin-angiotensin system (RAS) has been implicated in chronic intermittent hypoxia (CIH) hypertension. Since the subfornical organ (SFO) serves as a primary target for the central actions of circulating ANG II, we tested the effects of ANG II type 1a receptor (AT1aR) knockdown in the SFO on the sustained increase in MAP in this CIH model. Adeno-associated virus carrying green fluorescent protein (GFP) and small-hairpin RNA against either AT1aR or a scrambled control sequence (SCM) was stereotaxically injected in the SFO of rats. After recovery, MAP, heart rate, respiratory rate, and activity were continuously recorded using radiotelemetry. In the normoxic groups, the recorded variables did not deviate from the baseline values. Both CIH groups exhibited significant increases in MAP during CIH exposures (P < 0.05). During the normoxic dark phase in the CIH groups, only the SCM-injected group exhibited a sustained increase in MAP (P < 0.05). The AT1aR-CIH group showed significant decreases in FosB/ΔFosB staining in the median preoptic nucleus and the paraventricular nuclei of the hypothalamus compared with the SCM-CIH group. Our data indicate that AT1aRs in the SFO are critical for the sustained elevation in MAP and increased FosB/ΔFosB expression in forebrain autonomic nuclei associated with CIH.

  17. H2O2 generated by NADPH oxidase 4 contributes to transient receptor potential vanilloid 1 channel-mediated mechanosensation in the rat kidney.

    PubMed

    Lin, Chian-Shiung; Lee, Shang-Hsing; Huang, Ho-Shiang; Chen, Yih-Sharng; Ma, Ming-Chieh

    2015-08-15

    The presence of NADPH oxidase (Nox) in the kidney, especially Nox4, results in H2O2 production, which regulates Na(+) excretion and urine formation. Redox-sensitive transient receptor potential vanilloid 1 channels (TRPV1s) are distributed in mechanosensory fibers of the renal pelvis and monitor changes in intrapelvic pressure (IPP) during urine formation. The present study tested whether H2O2 derived from Nox4 affects TRPV1 function in renal sensory responses. Perfusion of H2O2 into the renal pelvis dose dependently increased afferent renal nerve activity and substance P (SP) release. These responses were attenuated by cotreatment with catalase or TRPV1 blockers. In single unit recordings, H2O2 activated afferent renal nerve activity in response to rising IPP but not high salt. Western blots revealed that Nox2 (gp91(phox)) and Nox4 are both present in the rat kidney, but Nox4 is abundant in the renal pelvis and originates from dorsal root ganglia. This distribution was associated with expression of the Nox4 regulators p22(phox) and polymerase δ-interacting protein 2. Coimmunoprecipitation experiments showed that IPP increases polymerase δ-interacting protein 2 association with Nox4 or p22(phox) in the renal pelvis. Interestingly, immunofluorescence labeling demonstrated that Nox4 colocalizes with TRPV1 in sensory fibers of the renal pelvis, indicating that H2O2 generated from Nox4 may affect TRPV1 activity. Stepwise increases in IPP and saline loading resulted in H2O2 and SP release, sensory activation, diuresis, and natriuresis. These effects, however, were remarkably attenuated by Nox inhibition. Overall, these results suggest that Nox4-positive fibers liberate H2O2 after mechanostimulation, thereby contributing to a renal sensory nerve-mediated diuretic/natriuretic response.

  18. Enhanced binding capability of nuclear factor-κB with demethylated P2X3 receptor gene contributes to cancer pain in rats.

    PubMed

    Zhou, You-Lang; Jiang, Guo-Qin; Wei, Jinrong; Zhang, Hong-Hong; Chen, Wei; Zhu, Hongyan; Hu, Shufen; Jiang, Xinghong; Xu, Guang-Yin

    2015-10-01

    Nuclear factor-kappa B (NF-κB) signaling is implicated in both cancer development and inflammation processes. However, the roles and mechanisms of NF-κB signaling in the development of cancer-induced pain (CIP) remain unknown. This study was designed to investigate the roles of the p65 subunit of NF-κB in regulation of the purinergic receptor (P2X3R) plasticity in dorsal root ganglion (DRG) of CIP rats. We showed here that tumor cell injection produced mechanical and thermal hyperalgesia, and an enhanced body weight-bearing difference, which was correlated with an upregulation of p65 and P2X3R expression in lumber DRGs and a potentiation of ATP-evoked responses of tibia-innervating DRG neurons. Inhibition of NF-κB signaling using p65 inhibitor pyrrolidine dithiocarbamate, BAY-11-7082, or lentiviral-p65 short-hairpin RNA significantly attenuated CIP and reversed the activities of P2X3R. Interestingly, tumor cell injection led to a significant demethylation of CpG island in p2x3r gene promoter and enhanced ability of p65 to bind the promoter of p2x3r gene. Our findings suggest that upregulation of P2X3R expression was mediated by the enhanced binding capability of p65 with demethylated promoter of p2x3r gene, thus contributing to CIP. NF-κBp65 might be a potential target for treating CIP, a neuropathic pain generated by tumor cell-induced injury to nerves that innervate the skin.

  19. Delayed activation of spinal microglia contributes to the maintenance of bone cancer pain in female Wistar rats via P2X7 receptor and IL-18.

    PubMed

    Yang, Yan; Li, Hui; Li, Ting-Ting; Luo, Hao; Gu, Xi-Yao; Lü, Ning; Ji, Ru-Rong; Zhang, Yu-Qiu

    2015-05-20

    Accumulating evidence suggests that activation of spinal microglia contributes to the development of inflammatory and neuropathic pain. However, the role of spinal microglia in the maintenance of chronic pain remains controversial. Bone cancer pain shares features of inflammatory and neuropathic pain, but the temporal activation of microglia and astrocytes in this model is not well defined. Here, we report an unconventional role of spinal microglia in the maintenance of advanced-phase bone cancer pain in a female rat model. Bone cancer elicited delayed and persistent microglial activation in the spinal dorsal horn on days 14 and 21, but not on day 7. In contrast, bone cancer induced rapid and persistent astrocytic activation on days 7-21. Spinal inhibition of microglia by minocycline at 14 d effectively reduced bone cancer-induced allodynia and hyperalgesia. However, pretreatment of minocycline in the first week did not affect the development of cancer pain. Bone cancer increased ATP levels in CSF, and upregulated P2X7 receptor, phosphorylated p38, and IL-18 in spinal microglia. Spinal inhibition of P2X7/p-38/IL-18 pathway reduced advanced-phase bone cancer pain and suppressed hyperactivity of spinal wide dynamic range (WDR) neurons. IL-18 induced allodynia and hyperalgesia after intrathecal injection, elicited mechanical hyperactivity of WDR neurons in vivo, and increased the frequency of mEPSCs in spinal lamina IIo nociceptive synapses in spinal cord slices. Together, our findings demonstrate a novel role of microglia in maintaining advanced phase cancer pain in females via producing the proinflammatory cytokine IL-18 to enhance synaptic transmission of spinal cord nociceptive neurons.

  20. Enhanced binding capability of nuclear factor-κB with demethylated P2X3 receptor gene contributes to cancer pain in rats

    PubMed Central

    Zhou, You-Lang; Jiang, Guo-Qin; Wei, Jinrong; Zhang, Hong-Hong; Chen, Wei; Zhu, Hongyan; Hu, Shufen; Jiang, Xinghong; Xu, Guang-Yin

    2015-01-01

    Abstract Nuclear factor-kappa B (NF-κB) signaling is implicated in both cancer development and inflammation processes. However, the roles and mechanisms of NF-κB signaling in the development of cancer-induced pain (CIP) remain unknown. This study was designed to investigate the roles of the p65 subunit of NF-κB in regulation of the purinergic receptor (P2X3R) plasticity in dorsal root ganglion (DRG) of CIP rats. We showed here that tumor cell injection produced mechanical and thermal hyperalgesia, and an enhanced body weight–bearing difference, which was correlated with an upregulation of p65 and P2X3R expression in lumber DRGs and a potentiation of ATP-evoked responses of tibia-innervating DRG neurons. Inhibition of NF-κB signaling using p65 inhibitor pyrrolidine dithiocarbamate, BAY-11-7082, or lentiviral-p65 short-hairpin RNA significantly attenuated CIP and reversed the activities of P2X3R. Interestingly, tumor cell injection led to a significant demethylation of CpG island in p2x3r gene promoter and enhanced ability of p65 to bind the promoter of p2x3r gene. Our findings suggest that upregulation of P2X3R expression was mediated by the enhanced binding capability of p65 with demethylated promoter of p2x3r gene, thus contributing to CIP. NF-κBp65 might be a potential target for treating CIP, a neuropathic pain generated by tumor cell–induced injury to nerves that innervate the skin. PMID:26049406

  1. Surface expression of hippocampal NMDA GluN2B receptors regulated by fear conditioning determines its contribution to memory consolidation in adult rats

    PubMed Central

    Sun, Yan-Yan; Cai, Wei; Yu, Jie; Liu, Shu-Su; Zhuo, Min; Li, Bao-Ming; Zhang, Xue-Han

    2016-01-01

    The number and subtype composition of N-methyl-d-aspartate receptor (NMDAR) at synapses determines their functional properties and role in learning and memory. Genetically increased or decreased amount of GluN2B affects hippocampus-dependent memory in the adult brain. But in some experimental conditions (e.g., memory elicited by a single conditioning trial (1 CS-US)), GluN2B is not a necessary factor, which indicates that the precise role of GluN2B in memory formation requires further exploration. Here, we examined the role of GluN2B in the consolidation of fear memory using two training paradigms. We found that GluN2B was only required for the consolidation of memory elicited by five conditioning trials (5 CS-US), not by 1 CS-US. Strikingly, the expression of membrane GluN2B in CA1was training-strength-dependently increased after conditioning, and that the amount of membrane GluN2B determined its involvement in memory consolidation. Additionally, we demonstrated the increases in the activities of cAMP, ERK, and CREB in the CA1 after conditioning, as well as the enhanced intrinsic excitability and synaptic efficacy in CA1 neurons. Up-regulation of membrane GluN2B contributed to these enhancements. These studies uncover a novel mechanism for the involvement of GluN2B in memory consolidation by its accumulation at the cell surface in response to behavioral training. PMID:27487820

  2. Contribution of position alpha4S336 on functional expression and up-regulation of alpha4beta2 neuronal nicotinic receptors.

    PubMed

    López-Hernández, Gretchen Y; Biaggi-Labiosa, Nilza M; Torres-Cintrón, Alexis; Ortiz-Acevedo, Alejandro; Lasalde-Dominicci, José A

    2009-02-01

    Phosphorylation of the nicotinic acetylcholine receptor (nAChR) is believed to play a critical role in its nicotine-induced desensitization and up-regulation. We examined the contribution of a consensus PKC site in the alpha4 M3/M4 intracellular loop (alpha4S336) on the desensitization and up-regulation of alpha4beta2 nAChRs expressed in oocytes. Position alpha4S336 was replaced with either alanine to abolish potential phosphorylation at this site or with aspartic acid to mimic phosphorylation at this same site. Mutations alpha4S336A and alpha4S336D displayed a threefold increase in the ACh-induced response and an increase in ACh EC(50). Epibatidine binding revealed a three and sevenfold increase in surface expression for the alpha4S336A and alpha4S336D mutations, respectively, relative to wild-type, therefore, both mutations enhanced expression of the alpha4beta2 nAChR. Interestingly, the EC(50)'s and peak currents for nicotine activation remained unaffected in both mutants. Both mutations abolished the nicotine-induced up-regulation that is normally observed in the wild-type. The present data suggest that adding or removing a negative charge at this phosphorylation site cannot be explained by a simple straightforward on-and-off mechanism; rather a more complex mechanism(s) may govern the functional expression of the alpha4beta2 nAChR. Along the same line, our data support the idea that phosphorylation at multiple consensus sites in the alpha4 subunit could play a remarkable role on the regulation of the functional expression of the alpha4beta2 nAChR.

  3. P2Y12 receptor-mediated activation of spinal microglia and p38MAPK pathway contribute to cancer-induced bone pain

    PubMed Central

    Liu, Mingjuan; Yao, Ming; Wang, Hanqi; Xu, Longsheng; Zheng, Ying; Huang, Bing; Ni, Huadong; Xu, Shijie; Zhou, Xuyan; Lian, Qingquan

    2017-01-01

    Background Cancer-induced bone pain (CIBP) is one of the most challenging clinical problems due to a lack of understanding the mechanisms. Recent evidence has demonstrated that activation of microglial G-protein-coupled P2Y12 receptor (P2Y12R) and proinflammatory cytokine production play an important role in neuropathic pain generation and maintenance. However, whether P2Y12R is involved in CIBP remains unknown. Methods The purpose of this study was to investigate the role of P2Y12R in CIBP and its molecular mechanisms. Using the bone cancer model inoculated with Walker 256 tumor cells into the left tibia of Sprague Dawley rat, we blocked spinal P2Y12R through intrathecal administration of its selective antagonist MRS2395 (400 pmol/µL, 15 µL). Results We found that not only the ionized calcium-binding adapter molecule 1 (Iba-1)-positive microglia in the ipsilateral spinal cord but also mechanical allodynia was significantly inhibited. Furthermore, it decreased the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and the production of proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6), whereas it increased tumor necrosis factor-α (TNF-α). Conclusion Taken together, our present results suggest that microglial P2Y12R in the spinal cord may contribute to CIBP by the activation of spinal microglia and p38MAPK pathway, thus identifying a potential therapeutic target for the treatment of CIBP. PMID:28243146

  4. Alterations of androgen receptor-regulated enhancer RNAs (eRNAs) contribute to enzalutamide resistance in castration-resistant prostate cancer

    PubMed Central

    Zhao, Jingwen; Zhao, Yu; Wang, Liguo; Zhang, Jun; Karnes, R. Jeffrey; Kohli, Manish; Wang, Guixia; Huang, Haojie

    2016-01-01

    Enzalutamide is a second-generation anti-androgen for treatment of castration-resistant prostate cancer (CPRC). It prolongs survival of CRPC patients, but its overall survival benefit is relatively modest (4.8 months) and by 24 months most patients progress on enzalutamide. To date, however, the molecular mechanisms underlying enzalutamide resistance remain elusive. Herein, we report enzalutamide treatment-induced alterations of androgen receptor (AR)-regulated enhancer RNAs (AR-eRNAs) and their roles in enzalutamide-resistant growth and survival of CRPC cells. AR chromatin immunoprecipitation and high throughput sequencing (ChIP-seq) and RNA-seq analyses revealed that 188 and 227 AR-eRNAs were differentially expressed in enzalutamide-resistant LNCaP and C4-2 cells, respectively. The AR-eRNAs upregulated in C4-2 cells and downregulated in LNCaP cells were selected through meta-analysis. Expression of AR-eRNAs and related mRNAs in the loci of FTO, LUZP2, MARC1 and NCAM2 were further verified by real-time RT-PCR. Silencing of LUZP2 inhibited, but silencing of MARC1 increased the growth of enzalutamide-resistant C4-2 cells. Intriguingly, meta-analysis showed that expression of LUZP2 mRNA increased in primary tumors compared to normal prostate tissues, but decreased again in metastatic CRPC. Our findings suggest that eRNA alteration profiling is a viable new approach to identify functional gene loci that may not only contribute to enzalutamide-resistant growth of CRPC, but also serve as new targets for CRPC therapy. PMID:27221037

  5. PI3K/Akt contributes to increased expression of Toll-like receptor 4 in macrophages exposed to hypoxic stress

    SciTech Connect

    Kim, So Young; Jeong, Eunshil; Joung, Sun Myung; Lee, Joo Young

    2012-03-16

    Highlights: Black-Right-Pointing-Pointer Hypoxic stress-induced TLR4 expression is mediated by PI3K/Akt in macrophages. Black-Right-Pointing-Pointer PI3K/Akt regulated HIF-1 activation leading to TLR4 expression. Black-Right-Pointing-Pointer p38 mitogen-activated protein kinase was not involved in TLR4 expression by hypoxic stress. Black-Right-Pointing-Pointer Sulforaphane suppressed hypoxia-mediated TLR4 expression by inhibiting PI3K/Akt. -- Abstract: Toll-like receptors (TLRs) play critical roles in triggering immune and inflammatory responses by detecting invading microbial pathogens and endogenous danger signals. Increased expression of TLR4 is implicated in aggravated inflammatory symptoms in ischemic tissue injury and chronic diseases. Results from our previous study showed that TLR4 expression was upregulated by hypoxic stress mediated by hypoxia-inducible factor-1 (HIF-1) at a transcriptional level in macrophages. In this study, we further investigated the upstream signaling pathway that contributed to the increase of TLR4 expression by hypoxic stress. Either treatment with pharmacological inhibitors of PI3K and Akt or knockdown of Akt expression by siRNA blocked the increase of TLR4 mRNA and protein levels in macrophages exposed to hypoxia and CoCl{sub 2}. Phosphorylation of Akt by hypoxic stress preceded nuclear accumulation of HIF-1{alpha}. A PI3K inhibitor (LY294002) attenuated CoCl{sub 2}-induced nuclear accumulation and transcriptional activation of HIF-1{alpha}. In addition, HIF-1{alpha}-mediated upregulation of TLR4 expression was blocked by LY294002. Furthermore, sulforaphane suppressed hypoxia- and CoCl{sub 2}-induced upregulation of TLR4 mRNA and protein by inhibiting PI3K/Akt activation and the subsequent nuclear accumulation and transcriptional activation of HIF-1{alpha}. However, p38 was not involved in HIF-1{alpha} activation and TLR4 expression induced by hypoxic stress in macrophages. Collectively, our results demonstrate that PI3K

  6. Differential α4(+)/(−)β2 Agonist-binding Site Contributions to α4β2 Nicotinic Acetylcholine Receptor Function within and between Isoforms*

    PubMed Central

    Lucero, Linda M.; Weltzin, Maegan M.; Eaton, J. Brek; Cooper, John F.; Lindstrom, Jon M.; Lukas, Ronald J.; Whiteaker, Paul

    2016-01-01

    Two α4β2 nicotinic acetylcholine receptor (α4β2-nAChR) isoforms exist with (α4)2(β2)3 and (α4)3(β2)2 subunit stoichiometries and high versus low agonist sensitivities (HS and LS), respectively. Both isoforms contain a pair of α4(+)/(−)β2 agonist-binding sites. The LS isoform also contains a unique α4(+)/(−)α4 site with lower agonist affinity than the α4(+)/(−)β2 sites. However, the relative roles of the conserved α4(+)/(−)β2 agonist-binding sites in and between the isoforms have not been studied. We used a fully linked subunit concatemeric nAChR approach to express pure populations of HS or LS isoform α4β2*-nAChR. This approach also allowed us to mutate individual subunit interfaces, or combinations thereof, on each isoform background. We used this approach to systematically mutate a triplet of β2 subunit (−)-face E-loop residues to their non-conserved α4 subunit counterparts or vice versa (β2HQT and α4VFL, respectively). Mutant-nAChR constructs (and unmodified controls) were expressed in Xenopus oocytes. Acetylcholine concentration-response curves and maximum function were measured using two-electrode voltage clamp electrophysiology. Surface expression was measured with 125I-mAb 295 binding and was used to define function/nAChR. If the α4(+)/(−)β2 sites contribute equally to function, making identical β2HQT substitutions at either site should produce similar functional outcomes. Instead, highly differential outcomes within the HS isoform, and between the two isoforms, were observed. In contrast, α4VFL mutation effects were very similar in all positions of both isoforms. Our results indicate that the identity of subunits neighboring the otherwise equivalent α4(+)/(−)β2 agonist sites modifies their contributions to nAChR activation and that E-loop residues are an important contributor to this neighbor effect. PMID:26644472

  7. Differential α4(+)/(-)β2 Agonist-binding Site Contributions to α4β2 Nicotinic Acetylcholine Receptor Function within and between Isoforms.

    PubMed

    Lucero, Linda M; Weltzin, Maegan M; Eaton, J Brek; Cooper, John F; Lindstrom, Jon M; Lukas, Ronald J; Whiteaker, Paul

    2016-01-29

    Two α4β2 nicotinic acetylcholine receptor (α4β2-nAChR) isoforms exist with (α4)2(β2)3 and (α4)3(β2)2 subunit stoichiometries and high versus low agonist sensitivities (HS and LS), respectively. Both isoforms contain a pair of α4(+)/(-)β2 agonist-binding sites. The LS isoform also contains a unique α4(+)/(-)α4 site with lower agonist affinity than the α4(+)/(-)β2 sites. However, the relative roles of the conserved α4(+)/(-)β2 agonist-binding sites in and between the isoforms have not been studied. We used a fully linked subunit concatemeric nAChR approach to express pure populations of HS or LS isoform α4β2*-nAChR. This approach also allowed us to mutate individual subunit interfaces, or combinations thereof, on each isoform background. We used this approach to systematically mutate a triplet of β2 subunit (-)-face E-loop residues to their non-conserved α4 subunit counterparts or vice versa (β2HQT and α4VFL, respectively). Mutant-nAChR constructs (and unmodified controls) were expressed in Xenopus oocytes. Acetylcholine concentration-response curves and maximum function were measured using two-electrode voltage clamp electrophysiology. Surface expression was measured with (125)I-mAb 295 binding and was used to define function/nAChR. If the α4(+)/(-)β2 sites contribute equally to function, making identical β2HQT substitutions at either site should produce similar functional outcomes. Instead, highly differential outcomes within the HS isoform, and between the two isoforms, were observed. In contrast, α4VFL mutation effects were very similar in all positions of both isoforms. Our results indicate that the identity of subunits neighboring the otherwise equivalent α4(+)/(-)β2 agonist sites modifies their contributions to nAChR activation and that E-loop residues are an important contributor to this neighbor effect.

  8. Oxytocin receptor gene and racial ingroup bias in empathy-related brain activity.

    PubMed

    Luo, Siyang; Li, Bingfeng; Ma, Yina; Zhang, Wenxia; Rao, Yi; Han, Shihui

    2015-04-15

    The human brain responds more strongly to racial ingroup than outgroup individuals' pain. This racial ingroup bias varies across individuals and has been attributed to social experiences. What remains unknown is whether the racial ingroup bias in brain activity is associated with a genetic polymorphism. We investigated genetic associations of racial ingroup bias in the brain activity to racial ingroup and outgroup faces that received painful or non-painful stimulations by scanning A/A and G/G homozygous of the oxytocin receptor gene polymorphism (OXTR rs53576) using functional MRI. We found that G/G compared to A/A individuals showed stronger activity in the anterior cingulate and supplementary motor area (ACC/SMA) in response to racial ingroup members' pain, whereas A/A relative to G/G individuals exhibited greater activity in the nucleus accumbens (NAcc) in response to racial outgroup members' pain. Moreover, the racial ingroup bias in ACC/SMA activity positively predicted participants' racial ingroup bias in implicit attitudes and NAcc activity to racial outgroup individuals' pain negatively predicted participants' motivations to reduce racial outgroup members' pain. Our results suggest that the two variants of OXTR rs53576 are associated with racial ingroup bias in brain activities that are linked to implicit attitude and altruistic motivation, respectively.

  9. A Constructive Replication of the Association between the Oxytocin Receptor Genotype and Parenting

    PubMed Central

    Klahr, Ashlea M.; Klump, Kelly L.; Burt, S. Alexandra

    2015-01-01

    Behavioral genetic studies have robustly indicated that parenting behaviors are heritable – that is, individual differences in parenting are at least partially a function of genetic differences between persons. Few studies, however, have sought to identify the specific genetic variants that are associated with individual differences in parenting. Genes that influence the oxytocin system are of particular interest, given the growing body of evidence that points to the role of oxytocin for social behaviors, including parenting. The current study conducted examinations of associations between a variant in the oxytocin receptor gene (OXTR rs53576) and parental warmth, control, and negativity in a sample of 1,000 twin children and their parents (N=500 families) from the Michigan State University Twin Registry to constructively replicate and extend prior work (Bakermans-Kranenburg & van IJzendoorn, 2008; Michalska et al., 2014). Analyses were conducted both at the level of the child and the level of the parent, allowing us to examine both child-driven (via evocative gene-environment correlation) and parent-driven genetic effects on parenting. Mothers’ OXTR genotype predicted her warmth towards her children, even after controlling for child genotype. This association was not found for fathers. These findings add to the growing body of evidence linking oxytocin functioning to parental behavior and also highlight potential etiological differences in parenting across mothers and fathers. PMID:25419912

  10. Dimerization of the Vacuolar Receptors AtRMR1 and -2 from Arabidopsis thaliana Contributes to Their Localization in the trans-Golgi Network

    PubMed Central

    Occhialini, Alessandro; Gouzerh, Guillaume; Di Sansebastiano, Gian-Pietro; Neuhaus, Jean-Marc

    2016-01-01

    In Arabidopsis thaliana, different types of vacuolar receptors were discovered. The AtVSR (Vacuolar Sorting Receptor) receptors are well known to be involved in the traffic to lytic vacuole (LV), while few evidences demonstrate the involvement of the receptors from AtRMR family (Receptor Membrane RING-H2) in the traffic to the protein storage vacuole (PSV). In this study we focused on the localization of two members of AtRMR family, AtRMR1 and -2, and on the possible interaction between these two receptors in the plant secretory pathway. Our experiments with agroinfiltrated Nicotiana benthamiana leaves demonstrated that AtRMR1 was localized in the endoplasmic reticulum (ER), while AtRMR2 was targeted to the trans-Golgi network (TGN) due to the presence of a cytosolic 23-amino acid sequence linker. The fusion of this linker to an equivalent position in AtRMR1 targeted this receptor to the TGN, instead of the ER. By using a Bimolecular Fluorescent Complementation (BiFC) technique and experiments of co-localization, we demonstrated that AtRMR2 can make homodimers, and can also interact with AtRMR1 forming heterodimers that locate to the TGN. Such interaction studies strongly suggest that the transmembrane domain and the few amino acids surrounding it, including the sequence linker, are essential for dimerization. These results suggest a new model of AtRMR trafficking and dimerization in the plant secretory pathway. PMID:27706038

  11. Contribution of Priority PAHs and POPs to Ah Receptor-Mediated Activities in Sediment Samples from the River Elbe Estuary, Germany

    PubMed Central

    Otte, Jens C.; Keiter, Steffen; Faßbender, Christopher; Higley, Eric B.; Rocha, Paula Suares; Brinkmann, Markus; Wahrendorf, Dierk-Steffen; Manz, Werner; Wetzel, Markus A.; Braunbeck, Thomas; Giesy, John P.; Hecker, Markus; Hollert, Henner

    2013-01-01

    The estuary of the River Elbe between Hamburg and the North Sea (Germany) is a sink for contaminated sediment and suspended particulate matter (SPM). One major concern is the effect of human activities on the hydrodynamics, particularly the intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priority PAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (<0.02–0.906 µg/g dw). Sediments contained relatively small concentrations of dioxin equivalents (Bio-TEQ) with concentrations ranging from 15.5 to 322 pg/g dw, which were significantly correlated with dioxin equivalents calculated based on toxicity reference values and concentrations of PAH. The concentration of Bio-TEQ at the reference site exceeded 200,000 pg/g dw. In a potency balance the 16 PAHs explained between 47 and 118% of the Bio-TEQ in the luciferase assay, which can be explained by the constant input of PAHs bound to SPM from the upper course of the Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such as sediments has rarely been reported. PMID:24146763

  12. Identification of transmembrane domain 1 & 2 residues that contribute to the formation of the ligand-binding pocket of the urotensin-II receptor.

    PubMed

    Sainsily, Xavier; Cabana, Jérôme; Holleran, Brian J; Escher, Emanuel; Lavigne, Pierre; Leduc, Richard

    2014-11-15

    The vasoactive urotensin-II (UII), a cyclic undecapeptide widely distributed in cardiovascular, renal and endocrine systems, specifically binds the UII receptor (UT receptor), a G protein-coupled receptor (GPCR). The involvement of this receptor in numerous pathophysiological conditions including atherosclerosis, heart failure, hypertension, renal impairment and diabetes potentially makes it an interesting therapeutic target. To elucidate how UII binds the UT receptor through the identification of specific residues in transmembrane domains (TM) one (TM1) and two (TM2) that are involved in the formation of the receptor's binding pocket, we used the substituted-cysteine accessibility method (SCAM). Each residue of TM1 (V49((1.30)) to M76((1.57))) and TM2 (V88((2.41)) to H117((2.70))) was mutated, one by one, to a cysteine. The resulting mutants were then expressed in COS-7 cells and subsequently treated with the sulfhydryl-specific alkylating agent methanethiosulfonate-ethylammonium (MTSEA). MTSEA treatment resulted in a significant binding inhibition of (125)I-UII to mutant I54C((1.35)) in TM1 and mutants Y100C((2.53)), S103C((2.56)), F106C((2.59)), I107C((2.60)), T110C((2.63)) and Y111C((2.64)) in TM2. These results identify key structural residues in TM1 and TM2 that participate in the formation of the UT receptor binding pocket. Together with previous SCAM analysis of TM3, TM4, TM5, TM6 and TM7, these results have led us to identify residues within all 7 TMs that participate in UT's binding pocket and have enabled us to propose a model of this receptor's orthosteric binding site.

  13. Reduced insulin-receptor mediated modulation of striatal dopamine release by basal insulin as a possible contributing factor to hyperdopaminergia in schizophrenia

    PubMed Central

    Caravaggio, Fernando; Hahn, Margaret; Nakajima, Shinichiro; Gerretsen, Philip; Remington, Gary; Graff-Guerrero, Ariel

    2017-01-01

    Schizophrenia is a severe and chronic neuropsychiatric disorder which affects 1% of the world population. Using the brain imaging technique positron emission tomography (PET) it has been demonstrated that persons with schizophrenia have greater dopamine transmission in the striatum compared to healthy controls. However, little progress has been made as to elucidating other biological mechanisms which may account for this hyperdopaminergic state in this disease. Studies in animals have demonstrated that insulin receptors are expressed on midbrain dopamine neurons, and that insulin from the periphery acts on these receptors to modify dopamine transmission in the striatum. This is pertinent given that several lines of evidence suggest that insulin receptor functioning may be abnormal in the brains of persons with schizophrenia. Post-mortem studies have shown that persons with schizophrenia have less than half the number of cortical insulin receptors compared to healthy persons. Moreover, these post-mortem findings are unlikely due to the effects of antipsychotic treatment; studies in cell lines and animals suggest antipsychotics enhance insulin receptor functioning. Further, hyperinsulinemia – even prior to antipsychotic use – seems to be related to less psychotic symptoms in patients with schizophrenia. Collectively, these data suggest that midbrain insulin receptor functioning may be abnormal in persons with schizophrenia, resulting in reduced insulin-mediated regulation of dopamine transmission in the striatum. Such a deficit may account for the hyperdopaminergic state observed in these patients and would help guide the development of novel treatment strategies. We hypothesize that, (i) insulin receptor expression and/or function is reduced in midbrain dopamine neurons in persons with schizophrenia, (ii) basal insulin should reduce dopaminergic transmission in the striatum via these receptors, and (iii) this modulation of dopaminergic transmission by basal

  14. Ion Fluxes through KCa2 (SK) and Cav1 (L-type) Channels Contribute to Chronoselectivity of Adenosine A1 Receptor-Mediated Actions in Spontaneously Beating Rat Atria

    PubMed Central

    Bragança, Bruno; Oliveira-Monteiro, Nádia; Ferreirinha, Fátima; Lima, Pedro A.; Faria, Miguel; Fontes-Sousa, Ana P.; Correia-de-Sá, Paulo

    2016-01-01

    Impulse generation in supraventricular tissue is inhibited by adenosine and acetylcholine via the activation of A1 and M2 receptors coupled to inwardly rectifying GIRK/KIR3.1/3.4 channels, respectively. Unlike M2 receptors, bradycardia produced by A1 receptors activation predominates over negative inotropy. Such difference suggests that other ion currents may contribute to adenosine chronoselectivity. In isolated spontaneously beating rat atria, blockade of KCa2/SK channels with apamin and Cav1 (L-type) channels with nifedipine or verapamil, sensitized atria to the negative inotropic action of the A1 agonist, R-PIA, without affecting the nucleoside negative chronotropy. Patch-clamp experiments in the whole-cell configuration mode demonstrate that adenosine, via A1 receptors, activates the inwardly-rectifying GIRK/KIR3.1/KIR3.4 current resulting in hyperpolarization of atrial cardiomyocytes, which may slow down heart rate. Conversely, the nucleoside inactivates a small conductance Ca2+-activated KCa2/SK outward current, which eventually reduces the repolarizing force and thereby prolong action potentials duration and Ca2+ influx into cardiomyocytes. Immunolocalization studies showed that differences in A1 receptors distribution between the sinoatrial node and surrounding cardiomyocytes do not afford a rationale for adenosine chronoselectivity. Immunolabelling of KIR3.1, KCa2.2, KCa2.3, and Cav1 was also observed throughout the right atrium. Functional data indicate that while both A1 and M2 receptors favor the opening of GIRK/KIR3.1/3.4 channels modulating atrial chronotropy, A1 receptors may additionally restrain KCa2/SK activation thereby compensating atrial inotropic depression by increasing the time available for Ca2+ influx through Cav1 (L-type) channels. PMID:27014060

  15. Identification of transmembrane domain 3, 4 & 5 residues that contribute to the formation of the ligand-binding pocket of the urotensin-II receptor.

    PubMed

    Sainsily, Xavier; Cabana, Jérôme; Boulais, Philip E; Holleran, Brian J; Escher, Emanuel; Lavigne, Pierre; Leduc, Richard

    2013-12-01

    Urotensin-II (UII), a cyclic undecapeptide, selectively binds the urotensin-II receptor (UT receptor), a G protein-coupled receptor (GPCR) involved in cardiovascular effects and associated with numerous pathophysiological conditions including hypertension, atherosclerosis, heart failure, pulmonary hypertension and others. In order to identify specific residues in transmembrane domains (TM) three (TM3), four (TM4) and five (TM5) that are involved in the formation of the UT receptor binding pocket, we used the substituted-cysteine accessibility method (SCAM). Each residue in the F118((3.20)) to S146((3.48)) fragment of TM3, the L168((4.44)) to G194((4.70)) fragment of TM4 and the W203((5.30)) to V232((5.59)) fragment of TM5, was mutated, individually, to a cysteine. The resulting mutants were then expressed in COS-7 cells and subsequently treated with the positively charged sulfhydryl-specific alkylating agent methanethiosulfonate-ethylammonium (MTSEA). MTSEA treatment resulted in a significant reduction in the binding of (125)I-UII to TM3 mutants L126C((3.28)), F127C((3.29)), F131C((3.33)) and M134C((3.36)) and TM4 mutants M184C((4.60)) and I188C((4.64)). No loss of binding was detected following treatment by MTSEA for all TM5 mutants tested. In absence of a crystal structure of UT receptor, these results identify key determinants in TM3, TM4 and TM5 that participate in the formation of the UT receptor binding pocket and has led us to propose a homology model of the UT receptor.

  16. Mu opioid receptors on primary afferent nav1.8 neurons contribute to opiate-induced analgesia: insight from conditional knockout mice.

    PubMed

    Weibel, Raphaël; Reiss, David; Karchewski, Laurie; Gardon, Olivier; Matifas, Audrey; Filliol, Dominique; Becker, Jérôme A J; Wood, John N; Kieffer, Brigitte L; Gaveriaux-Ruff, Claire

    2013-01-01

    Opiates are powerful drugs to treat severe pain, and act via mu opioid receptors distributed throughout the nervous system. Their clinical use is hampered by centrally-mediated adverse effects, including nausea or respiratory depression. Here we used a genetic approach to investigate the potential of peripheral mu opioid receptors as targets for pain treatment. We generated conditional knockout (cKO) mice in which mu opioid receptors are deleted specifically in primary afferent Nav1.8-positive neurons. Mutant animals were compared to controls for acute nociception, inflammatory pain, opiate-induced analgesia and constipation. There was a 76% decrease of mu receptor-positive neurons and a 60% reduction of mu-receptor mRNA in dorsal root ganglia of cKO mice. Mutant mice showed normal responses to heat, mechanical, visceral and chemical stimuli, as well as unchanged morphine antinociception and tolerance to antinociception in models of acute pain. Inflammatory pain developed similarly in cKO and controls mice after Complete Freund's Adjuvant. In the inflammation model, however, opiate-induced (morphine, fentanyl and loperamide) analgesia was reduced in mutant mice as compared to controls, and abolished at low doses. Morphine-induced constipation remained intact in cKO mice. We therefore genetically demonstrate for the first time that mu opioid receptors partly mediate opiate analgesia at the level of Nav1.8-positive sensory neurons. In our study, this mechanism operates under conditions of inflammatory pain, but not nociception. Previous pharmacology suggests that peripheral opiates may be clinically useful, and our data further demonstrate that Nav1.8 neuron-associated mu opioid receptors are feasible targets to alleviate some forms of persistent pain.

  17. Identification of residues in transmembrane regions III and VI that contribute to the ligand binding site of the serotonin 5-HT6 receptor.

    PubMed

    Boess, F G; Monsma, F J; Sleight, A J

    1998-11-01

    We have examined the ligand binding site of the serotonin 5-HT6 receptor using site-directed mutagenesis. Replacing the highly conserved Asp106 in transmembrane region III by asparagine eliminated D-[3H]-lysergic acid diethylamide ([3H]LSD) binding to the mutant receptor transiently expressed in HEK293 cells. The potency of 5-HT and LSD to stimulate adenylyl cyclase was reduced by 3,600- and 500-fold, respectively, suggesting that an ionic interaction between the positively charged amino group of 5-HT and D106 is essential for high-affinity binding and important for receptor activation. In addition, basal cyclic AMP levels in cells expressing this mutant were increased. Mutation of a tryptophan residue one helix turn toward the extracellular side of transmembrane region III (Trp102) to phenylalanine produced significant changes in the binding affinity and potency of several ligands, consistent with a role of this residue in the formation of the ligand binding site. The exchange of two neighboring residues in the carboxy-terminal half of transmembrane region VI (Ala287 and Asn288) for leucine and serine resulted in a mutant receptor with increased affinities (seven- to 30-fold) for sumatriptan and several ergopeptine ligands. The identification of these interactions will help to improve models of the 5-HT6 receptor ligand binding site.

  18. Allosteric signaling through an mGlu2 and 5-HT2A heteromeric receptor complex and its potential contribution to schizophrenia

    PubMed Central

    Moreno, José L.; Miranda-Azpiazu, Patricia; García-Bea, Aintzane; Younkin, Jason; Cui, Meng; Kozlenkov, Alexey; Ben-Ezra, Ariel; Voloudakis, Georgios; Fakira, Amanda K.; Baki, Lia; Ge, Yongchao; Georgakopoulos, Anastasios; Morón, José A.; Milligan, Graeme; López-Giménez, Juan F.; Robakis, Nikolaos K.; Logothetis, Diomedes E.; Meana, J. Javier; González-Maeso, Javier

    2016-01-01

    Heterotrimeric guanine nucleotide–binding protein (G protein)–coupled receptors (GPCRs) can form multiprotein complexes (heteromers), which can alter the pharmacology and functions of the constituent receptors. Previous findings demonstrated that the Gq/11-coupled serotonin 5-HT2A receptor and the Gi/o-coupled metabotropic glutamate 2 (mGlu2) receptor—GPCRs that are involved in signaling alterations associated with psychosis—assemble into a heteromeric complex in the mammalian brain. In single-cell experiments with various mutant versions of the mGlu2 receptor, we showed that stimulation of cells expressing mGlu2–5-HT2A heteromers with an mGlu2 agonist led to activation of Gq/11 proteins by the 5-HT2A receptors. For this crosstalk to occur, one of the mGlu2 subunits had to couple to Gi/o proteins, and we determined the relative location of the Gi/o-contacting subunit within the mGlu2 homodimer of the heteromeric complex. Additionally, mGlu2-dependent activation of Gq/11, but not Gi/o, was reduced in the frontal cortex of 5-HT2A knockout mice and was reduced in the frontal cortex of postmortem brains from schizophrenic patients. These findings offer structural insights into this important target in molecular psychiatry. PMID:26758213

  19. Distinct Functional Domains Contribute to Degradation of the Low Density Lipoprotein Receptor (LDLR) by the E3 Ubiquitin Ligase Inducible Degrader of the LDLR (IDOL)

    PubMed Central

    Sorrentino, Vincenzo; Scheer, Lilith; Santos, Ana; Reits, Eric; Bleijlevens, Boris; Zelcer, Noam

    2011-01-01

    We recently identified the liver X receptor-regulated E3 ubiquitin ligase inducible degrader of the LDL receptor (IDOL) as a modulator of lipoprotein metabolism. Acting as an E3 ubiquitin ligase, IDOL triggers ubiquitination and subsequent degradation of the low density lipoprotein receptor (LDLR). We demonstrate here that this outcome requires the conserved FERM and RING domains present in IDOL. The RING domain promotes ubiquitination in vitro and Lys-63-specific ubiquitination of the LDLR in vivo in response to IDOL or liver X receptor activation. We further identify RING residues that differentially influence ubiquitination of the LDLR or stability of IDOL. The FERM domain interacts with the LDLR and in living cells co-localizes with the receptor at the plasma membrane. Homology modeling revealed a phosphotyrosine-binding element embedded in the FERM domain. Mutating residues within this region or residues in the LDLR preceding the NPVY endocytosis motif abrogate LDLR degradation by IDOL. Collectively, our results indicate that both the FERM and RING domains are required for promoting lysosomal degradation of the LDLR by IDOL. Our findings may facilitate development of structure-based IDOL inhibitors aimed at increasing LDLR abundance in therapeutic strategies to treat cardiovascular disease. PMID:21734303

  20. 5-Hydroxytryptamine2C receptor contribution to m-chlorophenylpiperazine and N-methyl-beta-carboline-3-carboxamide-induced anxiety-like behavior and limbic brain activation.

    PubMed

    Hackler, Elizabeth A; Turner, Greg H; Gresch, Paul J; Sengupta, Saikat; Deutch, Ariel Y; Avison, Malcolm J; Gore, John C; Sanders-Bush, Elaine

    2007-03-01

    Activation of 5-hydroxytryptamine2C (5-HT(2C)) receptors by the 5-HT(2) receptor agonist m-chlorophenylpiperazine (m-CPP) elicits anxiety in humans and anxiety-like behavior in animals. We compared the effects of m-CPP with the anxiogenic GABA(A) receptor inverse agonist N-methyl-beta-carboline-3-carboxamide (FG-7142) on both anxiety-like behavior and regional brain activation using functional magnetic resonance imaging (fMRI) in the rat. We also determined whether the selective 5-HT(2C) receptor antagonist SB 242084 [6-chloro-2,3-dihydro-5-methyl-N-[6-[(2-methyl-3-pyridinyl)oxy]-3-pyridinyl]-1H-indole-1-carboxyamide dihydrochloride] would blunt m-CPP or FG-7142-induced neuronal activation. Both m-CPP (3 mg/kg i.p.) and FG-7142 (10 mg/kg i.p.) elicited anxiety-like behavior when measured in the social interaction test, and pretreatment with SB 242084 (1 mg/kg i.p.) completely blocked the behavioral effects of both anxiogenic drugs. Regional brain activation in vivo in response to anxiogenic drug challenge was determined by blood oxygen level-dependent (BOLD) fMRI using a powerful 9.4T magnet. Region of interest analyses revealed that m-CPP and FG-7142 significantly increased BOLD signals in brain regions that have been linked to anxiety, including the amygdala, dorsal hippocampus, and medial hypothalamus. These BOLD signal increases were blocked by pretreatment with SB 242084. In contrast, injection of m-CPP and FG-7142 resulted in BOLD signal decreases in the medial prefrontal cortex that were not blocked by SB 242084. In conclusion, the brain activation signals produced by anxiogenic doses of both m-CPP and FG-7142 are mediated at least partially by the 5-HT(2C) receptor, indicating that this receptor is a key component in anxiogenic neural circuitry.

  1. Non-charged amino acids from three different domains contribute to link agonist binding to channel gating in alpha7 nicotinic acetylcholine receptors.

    PubMed

    Aldea, Marcos; Mulet, José; Sala, Salvador; Sala, Francisco; Criado, Manuel

    2007-10-01

    Binding of agonists to nicotinic acetylcholine receptors results in channel opening. Previously, we have shown that several charged residues at three different domains of the alpha7 nicotinic receptor are involved in coupling binding and gating, probably through a network of electrostatic interactions. This network, however, could also be integrated by other residues. To test this hypothesis, non-charged amino acids were mutated and expression levels and electrophysiological responses of mutant receptors were determined. Mutants at positions Asn47 and Gln48 (loop 2), Ile130, Trp134, and Gln140 (loop 7), and Thr264 (M2-M3 linker) showed poor or null functional responses, despite significant membrane expression. By contrast, mutants F137A and S265A exhibited a gain of function effect. In all cases, changes in dose-response relationships were small, EC(50) values being between threefold smaller and fivefold larger, arguing against large modifications of agonist binding. Peak currents decayed at the same rate in all receptors except two, excluding large effects on desensitization. Thus, the observed changes could be mostly caused by alterations of the gating characteristics. Moreover, analysis of double mutants showed an interconnection between some residues in these domains, especially Gln48 with Ile130, suggesting a potential coupling between agonist binding and channel gating through these amino acids.

  2. Contribution of the 37-kDa laminin receptor precursor in the anti-metastatic PSP94-derived peptide PCK3145 cell surface binding

    SciTech Connect

    Annabi, Borhane; Currie, Jean-Christophe; Bouzeghrane, Mounia; Dulude, Helene; Daigneault, Luc; Garde, Seema; Rabbani, Shafaat A.; Panchal, Chandra; Wu, Jinzi J.; Beliveau, Richard . E-mail: oncomol@nobel.si.uqam.ca

    2006-07-21

    Purpose: PCK3145 is an anti-metastatic synthetic peptide with promising therapeutic efficacy against hormone-refractory prostate cancer. The characterization of the PCK3145 peptide cell surface binding/internalization mechanisms and of the receptors involved remained to be explored. Results: [{sup 14}C]PCK3145 cell surface binding assays showed rapid and transient kinetic profile, that was inhibited by RGD peptides, laminin, hyaluronan, and type-I collagen. RGD peptides were however unable to inhibit PCK3145 intracellular uptake. Far-Western ligand binding studies enabled the identification of the 37-kDa laminin receptor precursor (37LRP) as a potential ligand for PCK3145. Overexpression of the recombinant 37LRP indeed led to an increase in PCK3145 binding but unexpectedly not to its uptake. Conclusions: Our data support the implication of laminin receptors in cell surface binding and in transducing PCK3145 anti-metastatic effects, and provide a rational for targeting cancers that express high levels of such laminin receptors.

  3. A comparison of four receptor models used to quantify the boreal wildfire smoke contribution to surface PM2.5 in Halifax, Nova Scotia during the BORTAS-B experiment

    NASA Astrophysics Data System (ADS)

    Gibson, M. D.; Haelssig, J.; Pierce, J. R.; Parrington, M.; Franklin, J. E.; Hopper, J. T.; Li, Z.; Ward, T. J.

    2014-09-01

    This paper presents a quantitative comparison of the four most commonly used receptor models, namely Absolute Principal Component Scores (APCS), Pragmatic Mass Closure (PMC), Chemical Mass Balance (CMB), and Positive Matrix Factorization (PMF). The models were used to predict the contributions of a wide variety of sources to PM2.5 mass in Halifax, Nova Scotia during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) experiment. However, particular emphasis was placed on the capacity of the models to predict the boreal wild fire smoke contributions during the BORTAS experiment. Using PMF, a new woodsmoke enrichment factor of 52 was estimated for use in the PMC receptor model. The results indicate that the APCS and PMC receptor models were not able to accurately resolve total PM2.5 mass concentrations below 2.0 μg m-3. CMB was better able to resolve these low PM2.5 concentrations, but it could not be run on 9 of the 45 days of PM2.5 samples. PMF was found to be the most robust of the four models since it was able to resolve PM2.5 mass below 2.0 μg m-3, predict PM2.5 mass on all 45 days, and utilized an unambiguous woodsmoke chemical marker. The median woodsmoke relative contribution to PM2.5 estimated using PMC, APCS, CMB and PMF were found to be 0.08, 0.09, 3.59 and 0.14 μg m-3, respectively. The contribution predicted by the CMB model seems to be clearly too high based on other observations. The use of levoglucosan as a tracer for woodsmoke was found to be vital for identifying this source.

  4. Investigation into the Antigenic Properties and Contributions to Growth in Blood of the Meningococcal Haemoglobin Receptors, HpuAB and HmbR

    PubMed Central

    Bidmos, Fadil A.; Chan, Hannah; Praekelt, Uta; Tauseef, Isfahan; Ali, Youssif M.; Kaczmarski, Edward B.; Feavers, Ian; Bayliss, Christopher D.

    2015-01-01

    Acquisition of iron from host complexes is mediated by four surface-located receptors of Neisseria meningitidis. The HmbR protein and heterodimeric HpuAB complex bind to haemoglobin whilst TbpBA and LbpBA bind iron-loaded transferrin and lactoferrin complexes, respectively. The haemoglobin receptors are unevenly distributed; disease-causing meningococcal isolates encode HmbR or both receptors while strains with only HpuAB are rarely-associated with disease. Both these receptors are subject to phase variation and 70–90% of disease isolates have one or both of these receptors in an ON expression state. The surface-expression, ubiquity and association with disease indicate that these receptors could be potential virulence factors and vaccine targets. To test for a requirement during disease, an hmbR deletion mutant was constructed in a strain (MC58) lacking HpuAB and in both a wild-type and TbpBA deletion background. The hmbR mutant exhibited an identical growth pattern to wild-type in whole blood from healthy human donors whereas growth of the tbpBA mutant was impaired. These results suggest that transferrin is the major source of iron for N. meningitidis during replication in healthy human blood. To examine immune responses, polyclonal antisera were raised against His-tagged purified-recombinant variants of HmbR, HpuA and HpuB in mice using monolipopolysaccharide as an adjuvant. Additionally, monoclonal antibodies were raised against outer membrane loops of HmbR presented on the surface of EspA, an E. coli fimbrial protein. All antisera exhibited specific reactivity in Western blots but HmbR and HpuA polyclonal sera were reactive against intact meningococcal cells. None of the sera exhibited bactericidal activity against iron-induced wild-type meningococci. These findings suggest that the HmbR protein is not required during the early stages of disease and that immune responses against these receptors may not be protective. PMID:26208277

  5. Frequency Facilitation at Mossy Fiber–CA3 Synapses of Freely Behaving Rats Contributes to the Induction of Persistent LTD via an Adenosine-A1 Receptor-Regulated Mechanism

    PubMed Central

    Hagena, Hardy

    2010-01-01

    Frequency facilitation (FF), comprising a rapid and multiple-fold increase in the magnitude of evoked field potentials, is elicited by low-frequency stimulation (LFS) at mossy fiber–CA3 synapses. Here, we show that in freely behaving rats, FF reliably occurs in response to 1 and 2Hz but not in response to 0.25-, 0.3-, or 0.5-Hz LFS. Strikingly, prolonged (∼600 s) FF was tightly correlated to the induction of long-term depression (LTD) in freely moving animals. Although LFS at 2 Hz elicited unstable FF and unstable LTD, application of LFS at 1 Hz elicited pronounced FF, as well as robust LTD that persisted for over 24 h. This correlation of prolonged FF with LTD was absent at stimulation frequencies that did not induce FF. The adenosine-A1 receptor appears to participate in these effects: Application of adenosine-A1, but not adenosine-A3, receptor antagonists enhanced mossy fiber synaptic transmission and occluded FF. Furthermore, adenosine-A1 receptor antagonism resulted in more stable FF at 1 or 2 Hz and elicited more potent LTD. These data support the fact that FF contributes to the enablement of long-term information storage at mossy fiber–CA3 synapses and that the adenosine-A1 receptor may regulate the thresholds for this process. PMID:19903765

  6. Distinct effects of mGlu4 receptor positive allosteric modulators at corticostriatal vs. striatopallidal synapses may differentially contribute to their antiparkinsonian action.

    PubMed

    Gubellini, Paolo; Melon, Christophe; Dale, Elena; Doller, Dario; Kerkerian-Le Goff, Lydia

    2014-10-01

    Metabotropic glutamate 4 (mGlu4) receptor is a promising target for the treatment of motor deficits in Parkinson's disease (PD). This is due in part to its localization at key basal ganglia (BG) synapses that become hyperactive in this pathology, particularly striatopallidal synapses. In this context, mGlu4 receptor activation using either orthosteric agonists or positive allosteric modulators (PAMs) improves motor symptoms in rodent PD models in certain conditions. However, literature data show that mGlu4 receptor PAMs have no effect at striatopallidal GABAergic synapses (unless combined with an orthosteric agonist) and on the firing activity of pallidal neurons, and fail to provide significant motor improvement in relevant PD models. This questions the mechanistic hypothesis that mGlu4 receptor PAMs should act at striatopallidal synapses to alleviate PD motor symptoms. To shed light on this issue, we performed brain slice electrophysiology experiments. We show that Lu AF21934, an mGlu4 PAM small-molecule probe-compound, was ineffective at striatopallidal synapses at all concentrations tested, while it significantly inhibited corticostriatal synaptic transmission. Similarly, Lu AF21934 did not affect electrophysiology readouts at striatopallidal synapses in the presence of haloperidol or in 6-hydroxydopamine-lesioned rats. Interestingly, co-application of Lu AF21934 with a glutamate transporter inhibitor revealed a significant inhibitory action at striatopallidal synapses. Possibly, this effect could rely on increased level/permanence of glutamate in the synaptic cleft. Such differential efficacy of mGlu4 receptor PAMs at corticostriatal vs. striatopallidal synapses raises several issues regarding the synaptic target(s) of these drugs in the BG, and challenges the mechanisms by which they alleviate motor deficits in experimental PD models.

  7. Dorsal versus ventral hippocampal contributions to trace and contextual conditioning: differential effects of regionally selective NMDA receptor antagonism on acquisition and expression.

    PubMed

    Czerniawski, Jennifer; Ree, Fredrick; Chia, Chester; Otto, Tim

    2012-07-01

    The dorsal and ventral subregions of the hippocampus likely play dissociable roles in some forms of learning. For example, we have previously demonstrated that temporary inactivation of ventral, but not dorsal, hippocampus dramatically impaired the acquisition of trace fear conditioning, while temporary inactivation of dorsal, but not ventral, hippocampus impaired spatially guided reinforced alternation (Czerniawski et al. (2009) Hippocampus 19:20-32). Importantly, emerging data suggest that lesions, temporary inactivation, and NMDA receptor antagonism within these subregions can produce quite different patterns of behavioral effects when administered into the same region. Specifically, while neither lesions nor temporary inactivation of dorsal hippocampus impair the acquisition of trace fear conditioning, learning in this paradigm is severely impaired by pre-training administration of the NMDA receptor antagonist dl-2-phosphonovaleric acid (APV) in dorsal hippocampus; the effect of NMDA receptor antagonism within ventral hippocampus on the acquisition and expression of trace conditioning, or on learning in general, has not yet been systematically explored. The present study extends our previous work examining the differential effect of lesions or inactivation of the dorsal and ventral hippocampal subregions by systematically examining the effect of regionally selective pre-training or pre-testing administration of APV on the acquisition and expression of trace and contextual fear conditioning. The results of these studies demonstrate that while pre-training NMDA receptor antagonism within either the dorsal or ventral subregion of the hippocampus impaired the acquisition of both trace and contextual conditioning, pre-testing NMDA receptor antagonism within ventral, but not dorsal, hippocampus impaired the expression of previously-acquired trace and contextual fear conditioning. These data suggest that selectively manipulating the integrity of individual subregions

  8. Contribution of Hippocampal 5-HT3 Receptors in Hippocampal Autophagy and Extinction of Conditioned Fear Responses after a Single Prolonged Stress Exposure in Rats.

    PubMed

    Wu, Zhong-Min; Yang, Li-Hua; Cui, Rong; Ni, Gui-Lian; Wu, Feng-Tian; Liang, Yong

    2017-05-01

    One of the hypotheses about the pathogenesis of posttraumatic stress disorder (PTSD) is the dysfunction of serotonin (5-HT) neurotransmission. While certain 5-HT receptor subtypes are likely critical for the symptoms of PTSD, few studies have examined the role of 5-HT3 receptor in the development of PTSD, even though 5-HT3 receptor is critical for contextual fear extinction and anxiety-like behavior. Therefore, we hypothesized that stimulation of 5-HT3 receptor in the dorsal hippocampus (DH) could prevent hippocampal autophagy and the development of PTSD-like behavior in animals. To this end, we infused SR57227, selective 5-HT3 agonist, into the DH after a single prolonged stress (SPS) treatment in rats. Three weeks later, we evaluated the effects of this pharmacological treatment on anxiety-related behaviors and extinction of contextual fear memory. We also accessed hippocampal autophagy and the expression of 5-HT3A subunit, Beclin-1, LC3-I, and LC3-II in the DH. We found that SPS treatment did not alter anxiety-related behaviors but prolonged the extinction of contextual fear memory, and such a behavioral phenomenon was correlated with increased hippocampal autophagy, decreased 5-HT3A expression, and increased expression of Beclin-1 and LC3-II/LC3-I ratio in the DH. Furthermore, intraDH infusions of SR57227 dose-dependently promoted the extinction of contextual fear memory, prevented hippocampal autophagy, and decreased expression of Beclin-1 and LC3-II/LC3-I ratio in the DH. These results indicated that 5-HT3 receptor in the hippocampus may play a critical role in the pathogenesis of hippocampal autophagy, and is likely involved in the pathophysiology of PTSD.

  9. H1 but not H2 histamine receptor activation contributes to the rise in skin blood flow during whole body heating in humans.

    PubMed

    Wong, Brett J; Wilkins, Brad W; Minson, Christopher T

    2004-11-01

    Recent evidence suggests a role for vasoactive intestinal polypeptide (VIP) in active vasodilatation and it has been shown that VIP-mediated vasodilatation includes a nitric oxide (NO) and histamine component. Thus, the purpose of this study was to determine the role of H1 and H2 histamine receptors and to examine a potential interaction between NO and histamine receptors in cutaneous active vasodilatation. Eleven subjects were instrumented with four microdialysis fibres. Site 1 served as a control and site 2 was perfused with l-NAME to inhibit nitric oxide synthase. Site 3 was perfused with either the H1 antagonist pyrilamine maleate or the H2 antagonist cimetidine. Site 4 was perfused with l-NAME plus pyrilamine maleate or l-NAME plus cimetidine. Laser-Doppler flowmetry (LDF) was used as an index of skin blood flow and cutaneous vascular conductance (CVC) was calculated as LDF/mean arterial pressure and normalized to maximal vasodilatation achieved via 28 mm sodium nitroprusside infusion. During whole body heating, subjects' sublingual temperature increased a minimum of 0.8 degrees C. In the H1 antagonist studies, CVC in l-NAME, pyrilamine, and combined l-NAME plus pyrilamine sites was significantly reduced compared with control (P < 0.001). The l-NAME and combined l-NAME plus pyrilamine sites were significantly reduced compared with pyrilamine only sites (P < 0.05) but no significant differences were observed between sites. In the H2 receptor antagonist studies, CVC in control sites was not significantly different from cimetidine sites. There was no difference between the l-NAME and combined l-NAME plus cimetidine sites but these sites were significantly attenuated compared with control and cimetidine only sites (P < 0.05). These data suggest the rise in skin blood flow during whole body heating contains an H1 histamine receptor component but do not support an H2 histamine receptor component. Furthermore, part of the NO-dependent component of active

  10. Triggering of toll-like receptor signaling pathways in T cells contributes to the anti-tumor efficacy of T cell responses.

    PubMed

    Salem, Mohamed Labib

    2011-06-30