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1

Essential role of eIF5A-1 and deoxyhypusine synthase in mouse embryonic development.  

PubMed

The eukaryotic initiation factor 5A (eIF5A) contains a polyamine-derived amino acid, hypusine [N(?)-(4-amino-2-hydroxybutyl)lysine]. Hypusine is formed post-translationally by the addition of the 4-aminobutyl moiety from the polyamine spermidine to a specific lysine residue, catalyzed by deoxyhypusine synthase (DHPS), and subsequent hydroxylation by deoxyhypusine hydroxylase (DOHH). The eIF5A precursor protein and both of its modifying enzymes are highly conserved, suggesting a vital cellular function for eIF5A and its hypusine modification. To address the functions of eIF5A and the first modification enzyme, DHPS, in mammalian development, we knocked out the Eif5a or the Dhps gene in mice. Eif5a heterozygous knockout mice and Dhps heterozygous knockout mice were viable and fertile. However, homozygous Eif5a1 (gt/gt) embryos and Dhps (gt/gt) embryos died early in embryonic development, between E3.5 and E7.5. Upon transfer to in vitro culture, homozygous Eif5a (gt/gt) or Dhps (gt/gt) blastocysts at E3.5 showed growth defects when compared to heterozygous or wild type blastocysts. Thus, the knockout of either the eIF5A-1 gene (Eif5a) or of the deoxyhypusine synthase gene (Dhps) caused early embryonic lethality in mice, indicating the essential nature of both eIF5A-1 and deoxyhypusine synthase in mammalian development. PMID:21850436

Nishimura, Kazuhiro; Lee, Seung Bum; Park, Jong Hwan; Park, Myung Hee

2012-02-01

2

Essential role of eIF5A-1 and deoxyhypusine synthase in mouse embryonic development  

PubMed Central

The eukaryotic initiation factor 5A (eIF5A) contains a polyamine-derived amino acid, hypusine [N?-(4-amino-2-hydroxybutyl)lysine]. Hypusine is formed post-translationally by the addition of the 4-aminobutyl moiety from the polyamine spermidine to a specific lysine residue, catalyzed by deoxyhypusine synthase (DHPS), and by subsequent hydroxylation by deoxyhypusine hydroxylase (DOHH). The eIF5A precursor protein and both of its modifying enzymes are highly conserved, suggesting a vital cellular function for eIF5A and its hypusine modification. To address the functions of eIF5A and the first modification enzyme, DHPS, in mammalian development, we knocked out the Eif5a or the Dhps gene in mice. Eif5a heterozygous knockout mice and Dhps heterozygous knockout mice were viable and fertile. However, homozygous Eif5a1 gt/gt embryos and Dhps gt/gt embryos died early in embryonic development, between E3.5 and E7.5. Upon transfer to in vitro culture, homozygous Eif5a gt/gt or Dhps gt/gt blastocysts at E3.5 showed growth defects when compared to heterozygous or wild type blastocysts. Thus, the knockout of either the eIF5A-1 gene (Eif5a) or of the deoxyhypusine synthase gene (Dhps) caused early embryonic lethality in mice, indicating the essential nature of both eIF5A-1 and deoxyhypusine synthase in mammalian development.

Nishimura, Kazuhiro; Lee, Seung Bum; Park, Jong Hwan; Park, Myung Hee

2011-01-01

3

Essential role of eIF5A-1 and deoxyhypusine synthase in mouse embryonic development  

Microsoft Academic Search

The eukaryotic initiation factor 5A (eIF5A) contains a polyamine-derived amino acid, hypusine [N?-(4-amino-2-hydroxybutyl)lysine]. Hypusine is formed post-translationally by the addition of the 4-aminobutyl moiety from\\u000a the polyamine spermidine to a specific lysine residue, catalyzed by deoxyhypusine synthase (DHPS), and subsequent hydroxylation\\u000a by deoxyhypusine hydroxylase (DOHH). The eIF5A precursor protein and both of its modifying enzymes are highly conserved, suggesting\\u000a a

Kazuhiro Nishimura; Seung Bum Lee; Jong Hwan Park; Myung Hee Park

4

Involvement. Senior citizens' recreational activities.  

PubMed

During the last 18 years, senior citizens in Viborg, Denmark, have participated in study circles based on the theory of impression pedagogy and socially relevant activities. They arrange excursions at home and abroad and make films about the trips. They teach schoolchildren, students at folk high schools, and nurses, as well as occupational therapists and physiotherapists. They publish poems and books, write role plays, stage musicals, sing in choirs, and function as tour guides in town. They set up educational color slide programmes on preventing bone fractures, dealing with the problem of reduced hearing, and the importance of healthy food and exercise. They travel abroad and talk about Denmark and the conditions for senior citizens in our country. With the support of the Danish Ministry for Social Affairs, they produce videos about their activities as a source of inspiration to others. The use of drugs by the participants in the study circles has declined, while the level of activities has increased, and none of the participants has ever had to enter residential care. PMID:1638895

Gregersen, U B

1992-06-01

5

Promoting Active Involvement in Today's Classrooms  

ERIC Educational Resources Information Center

In today's diverse classrooms and age of accountability, teachers need to use efficient, research-based instructional approaches that engage all students, promote interest and variety in learning and teaching, and provide immediate and continuous informal assessment data. This article presents a rationale for using active involvement techniques,…

Conderman, Greg; Bresnahan, Val; Hedin, Laura

2011-01-01

6

Proteomic analysis of SP600125-controlled TrkA-dependent targets in SK-N-MC neuroblastoma cells: inhibition of TrkA activity by SP600125.  

PubMed

The c-Jun N-terminal kinase (JNK) is well known to play an important role in cell death signaling of the p75 neurotrophin receptor. However, little has been studied about a role of JNK in the signaling pathways of the tropomyosin-related kinase A (TrkA) neurotrophin receptor. In this study, we investigated JNK inhibitor SP600125-controlled TrkA-dependent targets by proteomic analysis to better understand an involvement of JNK in TrkA-mediated signaling pathways. PDQuest image analysis and protein identification results showed that hnRNP C1/C2, ?-tubulin, ?-tubulin homolog, actin homolog, and eIF-5A-1 protein spots were upregulated by ectopic expression of TrkA, whereas ?-enolase, peroxiredoxin-6, PROS-27, HSP70, PP1-gamma, and PDH E1-alpha were downregulated by TrkA, and these TrkA-dependent upregulation and downregulation were significantly suppressed by SP600125. Notably, TrkA largely affected certain PTM(s) but not total protein amounts of the SP600125-controlled TrkA-dependent targets. Moreover, SP600125 strongly suppressed TrkA-mediated tyrosine phosphorylation signaling pathways as well as JNK signaling, indicating that SP600125 could function as a TrkA inhibitor. Taken together, our results suggest that TrkA could play an important role in the cytoskeleton, cell death, cellular processing, and glucose metabolism through activation or inactivation of the SP600125-controlled TrkA-dependent targets. PMID:24375967

Jung, Eun Joo; Park, Hyung Chul; Chung, Ky Hyun; Kim, Choong Won

2014-02-01

7

Aminoglycoside neurotoxicity involves NMDA receptor activation.  

PubMed

Previous studies have led to the hypothesis that the ototoxicity produced by aminoglycoside antibiotics involves the excitotoxic activation of cochlear NMDA receptors. If this hypothesis is correct, then these antibiotics should also injure neurons within the brain. Because aminoglycosides do not readily penetrate the blood brain barrier, we examined the effects of the aminoglycoside neomycin following intrastriatal injection. Neomycin (10-250 nmol) produced dose-dependent striatal damage manifested as an increased gliosis as measured by: (1) [3H]PK-11195 binding, (2) staining for the astrocytic marker glial fibrillary acidic protein (GFAP) and (3) staining for OX-6, an MHC class II antigen expressed by microglia and macrophages. Co-injection of subthreshhold doses of NMDA potentiates the striatal damage produced by neomycin (10 nmol). Moreover, neomycin-induced striatal damage is attenuated by a combination of the NMDA antagonists ifenprodil and 5, 7-dichlorokynurenic acid. Intrastriatal administration of compounds structurally related to neomycin, but devoid of modulatory actions at NMDA receptors (paromamine and 2-deoxystreptamine), fail to produce neuronal damage. These data support the hypothesis that aminoglycoside-induced ototoxicity is, in part, an excitotoxic process involving the activation of NMDA receptors. Moreover, aminoglycosides may damage the central nervous system in individuals with compromised blood brain barriers. PMID:9878779

Segal, J A; Harris, B D; Kustova, Y; Basile, A; Skolnick, P

1999-01-01

8

Immigrant Youth Involvement in School-Based Extracurricular Activities  

ERIC Educational Resources Information Center

Extracurricular activity involvement is generally beneficial toward student progress and success. Little is known, however, about immigrant youth involvement in school-based extracurricular activities. The author examined the patterns of Latino and Asian American youth extracurricular involvement by focusing on the pertinent role of immigrant…

Peguero, Anthony A.

2011-01-01

9

Immigrant Youth Involvement in School-Based Extracurricular Activities  

Microsoft Academic Search

Extracurricular activity involvement is generally beneficial toward student progress and success. Little is known, however, about immigrant youth involvement in school-based extracurricular activities. The author examined the patterns of Latino and Asian American youth extracurricular involvement by focusing on the pertinent role of immigrant generational status. Analyses, which draw from the Educational Longitudinal Study of 2002 and logistic regression analyses,

Anthony A. Peguero

2011-01-01

10

The Director of Physical Activity and Staff Involvement  

ERIC Educational Resources Information Center

Faculty and staff involvement in the Comprehensive School Physical Activity Program (CSPAP) begins with the Director of Physical Activity (DPA) motivating them to "buy in" to the need for a CSPAP. The DPA will need to train staff to develop and integrate physical activity throughout the school day, encourage them to be involved in the before- and…

Heidorn, Brent; Centeio, Erin

2012-01-01

11

INVOLVING HISPANIC PARENTS IN EDUCATIONAL ACTIVITIES THROUGH COLLABORATIVE RELATIONSHIPS  

Microsoft Academic Search

This article is based on a literature review of school districts' successful practices in involving Hispanic parents, particularly migrant and immigrant parents, in their children's school activities. It presents a brief overview of the tradition of parental involvement, followed by a force field analysis of factors, which facilitate or hinder the involvement in education of this population. Finally, the author

Alicia Salinas Sosa

12

Neonatal nursing staff time involved with medication-related activities.  

PubMed

A work sampling study involving 1920 observations derived from 48 2-hour observation periods is described. Approximately one-tenth of neonatal nurse time was spent on medication-related activities. just over one-third of this time involved medication preparation. It is suggested that the use of a pharmacy medication preparation service may be more cost-effective. PMID:8708179

Ridge, H E; While, A E

1995-10-01

13

A Profile of Latino School-Based Extracurricular Activity Involvement  

ERIC Educational Resources Information Center

Participation in school-based extracurricular activities influences educational success. Thus, it is important to depict a profile of school-based extracurricular activity involvement for a Latino student population that is marginalized in schools. This research uses the Educational Longitudinal Study of 2002 and logistic regression analyses to…

Peguero, Anthony A.

2010-01-01

14

Empirical Evidence or Intuition? An Activity Involving the Scientific Method  

ERIC Educational Resources Information Center

Students need to have basic understanding of scientific method during their introductory science classes and for this purpose an activity was devised which involved a game based on famous Monty Hall game problem. This particular activity allowed students to banish or confirm their intuition based on empirical evidence.

Overway, Ken

2007-01-01

15

Involvement in 12-step Activities and Treatment Outcomes  

PubMed Central

Background This study addresses the relative importance of specific 12-step activities to recovery, and how treatment affects participation in those activities. Method Data were from a clinical trial testing a 12-step facilitation intervention called MAAEZ. Participants (N=508) were recruited at treatment entry. Analyses examined 8 activities measured at baseline, 7 weeks, 6 months, and 12 months. Results In simultaneous equations, meeting attendance and having a sponsor were the only strong and consistent predictors of abstinence across time points, though other activities (i.e., use of a home group, befriending members, service work, and reading the literature) were significant in some analyses. Treatment involvement had mixed effects on activity participation over time. Conclusions Contradicting research suggesting that meeting attendance contributes little beyond other 12-step activities, results highlight the importance of consistent meeting attendance and sponsorship in recovery. Results suggest a need for enhanced facilitation of key activities even in typical 12-step-oriented treatment.

Zemore, S. E.; Subbaraman, M.; Tonigan, J. S.

2012-01-01

16

Rat preputial sebocyte differentiation involves peroxisome proliferator-activated receptors.  

PubMed

The hallmark of sebaceous epithelial cell (sebocyte) differentiation is the accumulation of fused neutral fat droplets. Very little sebocyte differentiation occurs, however, in primary or organ culture, even upon incubating with androgens, which are required for maturation in vivo. We hypothesized that sebocyte cell culture systems lack activators of the peroxisome proliferator-activated receptors that are involved in adipocyte differentiation. We here report that activation of peroxisome proliferator-activated receptor gamma and alpha by their respective specific ligands, a thiazolidinedione and a fibrate, induced lipid droplet formation in sebocytes but not epidermal cells. Linoleic acid and carbaprostacyclin, both peroxisome proliferator-activated receptor delta and alpha ligand-activators, were more effective but less specific, stimulating lipid formation in both types of cells. Either was more effective than the combination of peroxisome proliferator-activated receptor gamma and alpha activation, suggesting that peroxisome proliferator-activated receptor delta is involved in this lipid formation. Linoleic acid 0.1 mM stimulated significantly more advanced sebocyte maturation than any other treatment, including carbaprostacyclin, which suggests a distinct role of long chain fatty acids in sebocyte differentiation. Peroxisome proliferator-activated receptor gammal mRNA was demonstrated in sebocytes, but not in epidermal cells; it was more strongly expressed in freshly dispersed than in cultured sebocytes. In contrast, peroxisome proliferator-activated receptor delta mRNA was expressed to a similarly high extent before and after culture in both sebocytes and epidermal cells. These findings are compatible with the concepts that peroxisome proliferator-activated receptor gamma1 gene expression plays a unique role in the differentiation of sebocytes, while peroxisome proliferator-activated receptor delta activation and long chain fatty acids finalize sebocyte maturation and are capable of stimulating epidermal lipid formation. These findings have implications for the development of new modalities of treatment for acne vulgaris. PMID:9989800

Rosenfield, R L; Kentsis, A; Deplewski, D; Ciletti, N

1999-02-01

17

Identifying Associations between Student Achievement and Parental Involvement Activities  

ERIC Educational Resources Information Center

The revision and renewal of the Elementary and Secondary Education Act of 1965 will likely expand its parental involvement component to engage educators, parents, and community partners in supporting public education for children. This revisions call for best practices, but current literature fails to identify specific activities associated…

Waddle, Ann R.

2011-01-01

18

The effect of daily-activity patterns on crash involvement.  

PubMed

The main purpose of this study is to analyze the effect of daily-activity and travel patterns on the risk of crash involvement. To this end, we develop a model that integrates daily-activity and travel choices in a single framework, recognizing that these variables affect the risk of crashes. This model can therefore provide predictions of the expected changes in risk levels from the implementation of measures that affect the daily-activity patterns and the socio-economic characteristics of the population. The empirical analysis makes use of data collected during a household survey that includes crash information and trip diaries. The model is applied in a case study of an Arab town in Israel to analyze various transportation policies. The results of this research show that in addition to individuals' demographic and socio-economic characteristics, their daily-activity and travel patterns also have an impact on the risk of being involved in car crashes. The case study showed the potential of this framework for analyzing the effect of various social and transportation policies on road safety. To the best of our knowledge, this is the first time such relationships have been tested by using a disaggregate model and the first time activity-based models have been used to analyze exposure to the risk of road crashes. PMID:20728617

Elias, Wafa; Toledo, Tomer; Shiftan, Yoram

2010-11-01

19

48 CFR 3452.224-72 - Research activities involving human subjects.  

Code of Federal Regulations, 2013 CFR

... true Research activities involving human subjects. 3452.224-72 Section...224-72 Research activities involving human subjects. As prescribed in 3424...that includes research activities involving human subjects covered under 34 CFR part...

2013-10-01

20

Involvement of novel autophosphorylation sites in ATM activation.  

PubMed

ATM kinase plays a central role in signaling DNA double-strand breaks to cell cycle checkpoints and to the DNA repair machinery. Although the exact mechanism of ATM activation remains unknown, efficient activation requires the Mre11 complex, autophosphorylation on S1981 and the involvement of protein phosphatases and acetylases. We report here the identification of several additional phosphorylation sites on ATM in response to DNA damage, including autophosphorylation on pS367 and pS1893. ATM autophosphorylates all these sites in vitro in response to DNA damage. Antibodies against phosphoserine 1893 revealed rapid and persistent phosphorylation at this site after in vivo activation of ATM kinase by ionizing radiation, paralleling that observed for S1981 phosphorylation. Phosphorylation was dependent on functional ATM and on the Mre11 complex. All three autophosphorylation sites are physiologically important parts of the DNA damage response, as phosphorylation site mutants (S367A, S1893A and S1981A) were each defective in ATM signaling in vivo and each failed to correct radiosensitivity, genome instability and cell cycle checkpoint defects in ataxia-telangiectasia cells. We conclude that there are at least three functionally important radiation-induced autophosphorylation events in ATM. PMID:16858402

Kozlov, Sergei V; Graham, Mark E; Peng, Cheng; Chen, Philip; Robinson, Phillip J; Lavin, Martin F

2006-08-01

21

School Involvement Leave: Providing Leave for Parental Involvement in School Activities. Policy Briefing Series. Issue 18  

ERIC Educational Resources Information Center

One of the most important factors in school performance is parental involvement. However, many parents do not have the flexibility in their work schedules or the leave policies necessary to attend school functions. As a result, legislators are creating policies to address this issue. School involvement leave policies provide parents with…

Curlew, Mary; Weber, Julie

2009-01-01

22

40 CFR 13.5 - Claims involving criminal activities or misconduct.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Claims involving criminal activities or misconduct. 13.5...General § 13.5 Claims involving criminal activities or misconduct. (a) The Administrator will refer cases of suspected criminal activity or misconduct to...

2013-07-01

23

Deregulated Cdk5 Activity Is Involved in Inducing Alzheimer's Disease  

PubMed Central

Alzheimer’s disease (AD), the most devastating chronic neurodegenerative disease in adults, causes dementia and eventually, death of the affected individuals. Clinically, AD is characterized as late-onset, age-dependent cognitive decline due to loss of neurons in cortex and hippocampus. The pathologic corollary of these symptoms is the formation of senile plaques and neurofibrillary tangles. Senile plaques are formed due to accumulation of oligomeric amyloid beta (A?) forming fibrillary plaques. This occurs due to the amyloidogenic processing of the amyloid precursor protein (APP) by various secretases. On the other hand, neurofibrillary tangles are formed due to hyperphosphorylation of cytoskeleton proteins like tau and neurofilament. Both are hyperphosphorylated by cyclin-dependent kinase-5 (Cdk5) and are part of the paired helical filament (PHF), an integral part of neurofibrillary tangles. Unlike other cyclin-dependent kinases, Cdk5 plays a very important role in the neuronal development. Cdk5 gets activated by its neuronal activators p35 and p39. Upon stress, p35 and p39 are cleaved by calpain resulting in truncated products as p25 and p29. Association of Cdk5/p25 is longer and uncontrolled causing aberrant hyperphosphorylation of various substrates of Cdk5 like APP, tau and neurofilament, leading to neurodegenerative pathology like AD. Additionally recent evidence has shown increased levels of p25, A?, hyperactivity of Cdk5, phosphorylated tau and neurofilament in human AD brains. This review briefly describes the above-mentioned aspects of involvement of Cdk5 in the pathology of AD and at the end summarizes the advances in Cdk5 as a therapeutic target.

Shukla, Varsha; Skuntz, Susan; Pant, Harish C.

2012-01-01

24

Head Start Parent Involvement Activities: Measuring the Effect of School Based Parent Involvement Activities on Parent Efficacy in Early Childhood Learning  

ERIC Educational Resources Information Center

Purpose: The purpose of this position paper was to examine the impact of school based parent involvement activities on parent efficacy. Methodology: The paper explores research studies into school based activities on long term parent efficacy. Conclusions: Most schools are involving parents in school-based activities in a variety of ways but the…

Quadri, Khadijat O.

2012-01-01

25

The activity involvement of women and men in young and middle adulthood: A panel study  

Microsoft Academic Search

In a secondary analyses of a 36?year panel study of 267 Euro?American women and men, this research examined gender differences in (a) the frequency of individuals’ involvement in discretionary or free?time activity in young and middle adulthood, (b) change in activity involvement between young and middle adulthood, and (c) predictors of activity involvement in young and middle adulthood. Activity involvement

Valeria J. Freysinger; Robert O. Ray

1994-01-01

26

Organized Activity Involvement among Rural Youth: Gender Differences in Associations between Activity Type and Developmental Outcomes  

ERIC Educational Resources Information Center

The current study examined associations between organized activity involvement, academic achievement, and problem behavior in a sample of youth from a non-agricultural based rural community (M[subscript age] = 15.26, Age range = 11-19 years, N = 456). Analyses examined whether associations varied as a function of adolescent gender and age.…

Ferris, Kaitlyn A.; Oosterhoff, Benjamin; Metzger, Aaron

2013-01-01

27

Antithrombin Regulates Matriptase Activity Involved in Plasmin Generation, Syndecan Shedding, and HGF Activation in Keratinocytes  

PubMed Central

Matriptase, a membrane-associated serine protease, plays an essential role in epidermal barrier function through activation of the glycosylphosphatidylinositol (GPI)-anchored serine protease prostasin. The matriptase-prostasin proteolytic cascade is tightly regulated by hepatocyte growth factor activator inhibitor (HAI)-1 such that matriptase autoactivation and prostasin activation occur simultaneously and are followed immediately by the inhibition of both enzymes by HAI-1. However, the mechanisms whereby matriptase acts on extracellular substrates remain elusive. Here we report that some active matriptase can escape HAI-1 inhibition by being rapidly shed from the cell surface. In the pericellular environment, shed active matriptase is able to activate hepatocyte growth factor (HGF), accelerate plasminogen activation, and shed syndecan 1. The amount of active matriptase shed is inversely correlated with the amount of antithrombin (AT) bound to the surface of the keratinocytes. Binding of AT to the surface of keratinocytes is dependent on a functional heparin binding site, Lys-125, and that the N-glycosylation site Asn-135 be unglycosylated. This suggests that ?-AT, and not ?-AT, is responsible for regulation of pericellular matriptase activity in keratinocytes. Keratinocytes appear to rely on AT to regulate the level of pericellular active matriptase much more than breast and prostate epithelial cells in which AT regulation of matriptase activity occurs at much lower levels than keratinocytes. These results suggest that keratinocytes employ two distinct serine protease inhibitors to control the activation and processing of two different sets of matriptase substrates leading to different biological events: 1) HAI-1 for prostasin activation/inhibition, and 2) AT for the pericellular proteolysis involved in HGF activation, accelerating plasminogen activation, and shedding of syndecans.

Chen, Ya-Wen; Xu, Zhenghong; Baksh, Adrienne N. H.; Wang, Jehng-Kang; Chen, Chiu-Yuan; Swanson, Richard; Olson, Steve T.; Kataoka, Hiroaki; Johnson, Michael D.; Lin, Chen-Yong

2013-01-01

28

Extracurricular Activity Involvement and Adolescent Self-Esteem  

ERIC Educational Resources Information Center

Structured extracurricular activity participation has been linked to self-esteem and other indicators of positive youth development. This article describes the theoretical basis for this relationship, centering on extracurricular activities as a location for identity development. A summary of the empirical evidence points to the importance of…

Kort-Butler, Lisa A.

2012-01-01

29

Human tracking studies involving an actively powered, augmented exoskeleton  

Microsoft Academic Search

An actively powered, augmented, exoskeleton system is studied within a speed-accuracy performance task framework with human subjects. This system has a dual use in military applications as well as for the rehabilitation of patients with neuromotor disorders

D. W. Repperger; B. O. Hill; C. Hasser; M. Roark; C. A. Phillips

1996-01-01

30

Involvement of Antilipoarabinomannan Antibodies in Classical Complement Activation in Tuberculosis  

PubMed Central

We examined alternative and classical complement activation induced by whole bacilli of Mycobacterium bovis BCG and Mycobacterium tuberculosis products. After exposure to BCG, there were higher levels of the terminal complement complex in sera from Indian tuberculosis patients than in sera from healthy controls. The addition of BCG with or without EGTA to these sera indicated that approximately 70 to 85% of the total levels of the terminal complement complex was formed by classical activation. Sera from Indian tuberculosis patients contained more antibody to lipoarabinomannan (LAM) than sera from healthy Indians. Levels of anti-LAM immunoglobulin G2 (IgG2), but not anti-LAM IgM, correlated positively with classical activation induced by BCG in the sera. By flow cytometry, deposition of C3 and terminal complement complex on bacilli incubated with normal human serum was demonstrated. The anticomplement staining was significantly reduced in the presence of EGTA and EDTA. Flow cytometry also revealed the binding of complement to BCG incubated with rabbit anti-LAM and then with factor B-depleted serum. This indicates that classical activation plays a major role in complement activation induced by mycobacteria and that anti-LAM IgG on the bacilli can mediate this response. Classical complement activation may be important for the extent of phagocytosis of M. tuberculosis by mononuclear phagocytes, which may influence the course after infection.

Hetland, Geir; Wiker, Harald G.; H?gasen, Kolbj?rn; Hamasur, Beston; Svenson, Stefan B.; Harboe, Morten

1998-01-01

31

Comparison of involvement between traditional and technology-assisted (Wii) physical activities in early childhood education  

Microsoft Academic Search

This study compared the differences of involvement scale between traditional and technology assisted physical activities. Seventeen (12 girls and 5 boys) 5-year-olds participated in both traditional running game (15 minutes) and Wii Fit jogging game (15 minutes). Observation was used to study the child's level of involvement. The study found that technology assisted physical activities involved participants higher than traditional

Gretchen H Geng; Leigh P Disney

2010-01-01

32

Community Representatives' Involvement in Clinical and Translational Science Awardee Activities  

PubMed Central

Objectives:?To understand the formal roles of community representatives (CRs) in Clinical and Translational Science Awardee (CTSA) activities, to evaluate the extent of integration into the organizational and governance structures and to identify barriers to effective integration. Methods:?The inventory tool was distributed to each of the 60 CTSAs using a secure web application. Results:?Forty-seven (78%) completed the inventory. The mean number of CRs per CTSA is 21.4 (SD: 14.8). Most CTSAs had community advisory boards (89%) and 94% included CRs in Community Engagement (CE) cores. Only 11% reported a CR being a member of the CTSA leadership team and 19% reported that CRs advise core programs beyond CE. CRs are compensated by 79% of CTSAs. Mean annual compensation is $753 (median: $400). Compensation directly correlated with the number of hours that CRs worked in CTSA activities (r = 0.64; P = 0.001). Conclusions:?This inventory allows CTSAs to better understand how CRs have engaged in activities and brings attention to the limited representation among cores and in leadership roles. CTSAs should, with substantive input from CRs, develop strategies to provide the resources and compensation necessary to better integrate the community in CTSA activities and fully realize the goals of the CTSA vision.

Wilkins, Consuelo H; Spofford, Mark; Williams, Neely; McKeever, Corliss; Allen, Shauntice; Brown, Jen; Opp, Jennifer; Richmond, Alan; Strelnick, A Hal

2013-01-01

33

BIOLOGICAL ACTIVITY AND POTENTIAL REMEDIATION INVOLVING GEOTEXTILE LANDFILL LEACHATE FILTERS  

EPA Science Inventory

This paper presents the results of a biological growth study in geotextile filters used in landfill leachate collection systems. fter reviewing the first year's activity, a completely new experimental approach has been taken. sing 100 mm diameter columns for the experimental incu...

34

MicroRNA Involvement in Immune Activation During Heart Failure  

Microsoft Academic Search

Heart failure is one of the common end stages of cardiovascular diseases, the leading cause of death in developed countries.\\u000a Molecular mechanisms underlying the development of heart failure remain elusive but there is a consistent observation of chronic\\u000a immune activation and aberrant microRNA (miRNA) expression that is present in failing hearts. This review will focus on the\\u000a interplay between the

Mathijs van de Vrie; Stephane Heymans; Blanche Schroen

2011-01-01

35

Exercise and youth: Physical activity,sport involvement, and development  

Microsoft Academic Search

This article summarizes Plenary Session I, “Exercise and Youth,” at the 6th Annual Congress of the European College of Sport Science (Cologne, 24–28 July 2001). The session provided a broad overview of current knowledge and progress in the field. Using the results of cross-sectional studies, Dietrich Kurz of Germany demonstrated associations between sport activity and personal attributes of psychosocial and

Ulrike Wigger

2001-01-01

36

High glucose levels enhance platelet activation: involvement of multiple mechanisms.  

PubMed

Diabetes mellitus (DM) and hyperglycaemia are associated with platelet activation. The present study was designed to investigate how high glucose levels influence platelet function. Fasting human blood was incubated with different concentrations of D-glucose (5, 15 and 30 mmol/l) and other sugars without or with in vitro stimuli. Platelet activation was monitored by whole blood flow cytometry. High glucose levels enhanced adenosine diphosphate (ADP)- and thrombin receptor-activating peptide (TRAP)-induced platelet P-selectin expression, and TRAP-induced platelet fibrinogen binding. Similar effects were seen with 30 mmol/l L-glucose, sucrose and galactose. Hyperglycaemia also increased TRAP-induced platelet-leucocyte aggregation. Protein kinase C (PKC) blockade did not counteract the enhancement of platelet P-selectin expression, but abolished the enhancement of TRAP-induced platelet fibrinogen binding by hyperglycaemia. Superoxide anion scavenging by superoxide dismutase (SOD) attenuated the hyperglycaemic enhancement of platelet P-selectin expression, but did not counteract the enhancement of TRAP-induced platelet fibrinogen binding. Hyperglycaemia did not alter platelet intracellular calcium responses to agonist stimulation. Blockade of cyclo-oxygenase (COX), phosphotidylinositol-3 (PI3) kinase, or nitric oxide synthase, or the addition of insulin did not influence the effect of hyperglycaemia. In conclusion, high glucose levels enhanced platelet reactivity to agonist stimulation through elevated osmolality. This occurred via superoxide anion production, which enhanced platelet P-selectin expression (secretion), and PKC signalling, which enhanced TRAP-induced fibrinogen binding (aggregablity). PMID:16643434

Sudic, Dzana; Razmara, Masoud; Forslund, Mikael; Ji, Qiushang; Hjemdahl, Paul; Li, Nailin

2006-05-01

37

WRKY Transcription Factors Involved in Activation of SA Biosynthesis Genes  

PubMed Central

Background Increased defense against a variety of pathogens in plants is achieved through activation of a mechanism known as systemic acquired resistance (SAR). The broad-spectrum resistance brought about by SAR is mediated through salicylic acid (SA). An important step in SA biosynthesis in Arabidopsis is the conversion of chorismate to isochorismate through the action of isochorismate synthase, encoded by the ICS1 gene. Also AVRPPHB SUSCEPTIBLE 3 (PBS3) plays an important role in SA metabolism, as pbs3 mutants accumulate drastically reduced levels of SA-glucoside, a putative storage form of SA. Bioinformatics analysis previously performed by us identified WRKY28 and WRKY46 as possible regulators of ICS1 and PBS3. Results Expression studies with ICS1 promoter::?-glucuronidase (GUS) genes in Arabidopsis thaliana protoplasts cotransfected with 35S::WRKY28 showed that over expression of WRKY28 resulted in a strong increase in GUS expression. Moreover, qRT-PCR analyses indicated that the endogenous ICS1 and PBS3 genes were highly expressed in protoplasts overexpressing WRKY28 or WRKY46, respectively. Electrophoretic mobility shift assays indentified potential WRKY28 binding sites in the ICS1 promoter, positioned -445 and -460 base pairs upstream of the transcription start site. Mutation of these sites in protoplast transactivation assays showed that these binding sites are functionally important for activation of the ICS1 promoter. Chromatin immunoprecipitation assays with haemagglutinin-epitope-tagged WRKY28 showed that the region of the ICS1 promoter containing the binding sites at -445 and -460 was highly enriched in the immunoprecipitated DNA. Conclusions The results obtained here confirm results from our multiple microarray co-expression analyses indicating that WRKY28 and WRKY46 are transcriptional activators of ICS1 and PBS3, respectively, and support this in silico screening as a powerful tool for identifying new components of stress signaling pathways.

2011-01-01

38

Dystroglycan receptor is involved in integrin activation in intestinal epithelia  

PubMed Central

The dystroglycans (?-DG and ?-DG), which play important roles in the formation of basement membranes, have been well studied in skeletal muscle and nerve, but their expression and localization in intestinal epithelial cells has not been previously investigated. Here, we demonstrated that the DG complex, composed of ?-DG, ?-DG, and utrophin, is specifically expressed in the basolateral membrane of the Caco-2-BBE monolayer. The DG complex coprecipitated with ?1-integrin, suggesting a possible interaction among these proteins. In addition, we observed that activation of DG receptors by laminin-1 enhanced the interaction between ?1-integrin and laminin-1, whereas activation of DG receptors by laminin-2 reduced the interaction between ?1-integrin and laminin-2. Finally, we demonstrated that the intracellular COOH-terminal tail of ?-DG and its binding to the DG binding domain of utrophin are crucial for the interactions between laminin-1/-2 and ?1-integrin. Collectively, these novel results indicate that dystroglycans play important roles in the regulation of interactions between intestinal epithelial cells and the extracellular matrix.

Driss, Adel; Charrier, Laetitia; Yan, Yutao; Nduati, Vivienne; Sitaraman, Shanthi; Merlin, Didier

2009-01-01

39

[Mammalian lignans: possible involvement in endogenous digitalis activity].  

PubMed

Lignans are natural products, some of which were recently discovered in animal urines, semen and blood plasma. We investigated the actions of animal lignans obtained by total synthesis or extracted from urines of pregnant women on Na+, K+-ATPase in human red cells and human and guinea-pig heart cell membranes. Some of the tested lignans (enterolactone, prestegane B and 3-O-methyl enterolactone) inhibited Na+, K+-pump activity in human red cells with IC50 ranging from 5 to 9 X 10(-4) M. The IC50 for ouabain (7 X 10(-7) M) was not modified by addition of lignans. Enterolactone inhibited Na+, K+-ATPase activity in human and guinea pig heart membranes. It also displaced [3H]-ouabain binding from human heart with IC50 = 1.5 X 10(-4) M. The apparent dissociation rate constants (kd) of [3H]-ouabain were not different in presence of digoxin or enterolactone. Enterolactone exhibited a poor cross reactivity against antidigoxin antibodies. The aglycones of the lignans studied here were slight inhibitors of the Na+, K+-ATPase. However, we cannot exclude that a glycosyl- (and/or butenolide-) derivative of enterolactone could be one "endogenous ouabain-like" factor. PMID:3013381

Braquet, P; Senn, N; Fagoo, M; Garay, R; Robin, J P; Esanu, A; Chabrier, E; Godfrain, T

1986-01-01

40

Anticancer Activity of Metal Complexes: Involvement of Redox Processes  

PubMed Central

Cells require tight regulation of the intracellular redox balance and consequently of reactive oxygen species for proper redox signaling and maintenance of metal (e.g., of iron and copper) homeostasis. In several diseases, including cancer, this balance is disturbed. Therefore, anticancer drugs targeting the redox systems, for example, glutathione and thioredoxin, have entered focus of interest. Anticancer metal complexes (platinum, gold, arsenic, ruthenium, rhodium, copper, vanadium, cobalt, manganese, gadolinium, and molybdenum) have been shown to strongly interact with or even disturb cellular redox homeostasis. In this context, especially the hypothesis of “activation by reduction” as well as the “hard and soft acids and bases” theory with respect to coordination of metal ions to cellular ligands represent important concepts to understand the molecular modes of action of anticancer metal drugs. The aim of this review is to highlight specific interactions of metal-based anticancer drugs with the cellular redox homeostasis and to explain this behavior by considering chemical properties of the respective anticancer metal complexes currently either in (pre)clinical development or in daily clinical routine in oncology.

Jungwirth, Ute; Kowol, Christian R.; Keppler, Bernhard K.; Hartinger, Christian G.; Berger, Walter; Heffeter, Petra

2012-01-01

41

Activation of peroxisome proliferator-activated receptor gamma suppresses mast cell maturation involved in allergic diseases  

PubMed Central

Background Mast cells play a central role in allergic and inflammatory diseases. Several reports indicated role of peroxisome proliferator-activated receptor gamma (PPAR?) on mast cell function. However, there is no report about the role of PPAR? on differentiation of mast cells from the progenitors. In this study, we investigated the role of PPAR? in regulating bone marrow-derived mast cell maturation and the therapeutic implications for mast cell-related diseases such as atopic or contact dermatitis. Methods We used in vitro cell culture system for mast cell differentiation from bone marrow-progenitors using specific ligands and lentiviral-mediated short hairpin RNA of PPAR?, and in vivo murine dermatitis models. Results Activation of PPAR? inhibited the maturation of bone marrow progenitors into connective tissue-type mast cells (CTMCs) through up-regulation of GATA-4 and GATA-6 resulting in a decrease in expression of histidine decarboxylase and mast cell histamine content. In comparison, the differentiation of bone marrow progenitors into CTMCs was significantly accelerated by the knockdown of PPAR? expression by lentiviral-mediated short hairpin RNA. Peroxisome proliferator-activated receptor gamma ligand administration to mice inhibited the maturation of mast cells resulting in attenuation of atopic and contact dermatitis via diminishment of the number of mature mast cells. Conclusion Our results indicate that PPAR? is one of master regulators on mast cell maturation and potentially useful for the therapy in various disorders involving mast cell activation.

Tachibana, M.; Wada, K.; Katayama, K.; Kamisaki, Y.; Maeyama, K.; Kadowaki, T.; Blumberg, R. S.; Nakajima, A.

2014-01-01

42

Behavioral Adaptation of Alpine Skiers to Climate Change: Examining Activity Involvement and Place Loyalty  

Microsoft Academic Search

This study employed a visitor survey to analyze the influence that changing climatic conditions have on the substitution behaviors of alpine skiers (activity, spatial, temporal). It further focuses on the role that activity involvement plays in influencing behavioral adaptations (i.e., substitution) and also the extent to which place loyalty is affected. The Modified Involvement Scale (MIS) was used to segment

Jackie Dawson; Mark Havitz; Daniel Scott

2011-01-01

43

Breadth and Intensity of Youth Activity Involvement as Contexts for Positive Development  

ERIC Educational Resources Information Center

Research has linked youth activity involvement to positive development. However, past studies have confounded at least two separable dimensions of involvement: breadth (number of activities) and intensity (participation frequency). Theory and the limited available evidence suggest that these dimensions may make independent contributions to…

Rose-Krasnor, Linda; Busseri, Michael A.; Willoughby, Teena; Chalmers, Heather

2006-01-01

44

African American Youths with Internalizing Difficulties: Relation to Social Support and Activity Involvement  

ERIC Educational Resources Information Center

Social support and positive activity involvement are considered protective factors that can help offset the risks for youths living in impoverished areas. This study investigated whether insufficient social support and activity involvement are related to internalizing difficulties, such as depression, anxiety, loneliness, and low self-esteem.…

Margolin, Sylvia

2006-01-01

45

Male involvement in child care activities: a review of the literature in Botswana.  

PubMed

Engaging men as partners in childrearing is critical because of the positive aspects on the child's development and reduction of childhood illnesses. The paper presents findings from a literature review whose aim was to assess the extent to which males are involved in child care activities. Findings revealed a limited number of studies conducted in the area of male involvement. Sociocultural factors have a negative influence on men's participation on child care activities. In addition, some laws were prohibitive to male involvement. It was difficult to assess the extent to which males were involved due to inadequate data collection tools. Recommendations include a study on male involvement, review of the existing Sexual and Reproductive Health data collection tools, development of a policy on paternity leave, strengthening training on male involvement; community sensitization on cultural stereotypes and harmonization of customary and common laws. PMID:24558780

Jorosi-Tshiamo, Wananani B; Mogobe, Keitshokile D; Mokotedi, Mosidi T

2013-12-01

46

Factors involved in the expression of gene activity in polytene chromosomes  

Microsoft Academic Search

In order to separate some of the factors involved in the formation of puffs the antibiotic actinomycin D was applied at different stages of puff activity. Puffs were induced by temperature shocks or eodysone.

H. D. Berendes

1968-01-01

47

Molecular genetic analysis of activation-tagged transcription factors thought to be involved in photomorphogenesis  

SciTech Connect

This is a final report for Department of Energy Grant No. DE-FG02-08ER15927 entitled “Molecular Genetic Analysis of Activation-Tagged Transcription Factors Thought to be Involved in Photomorphogenesis”. Based on our preliminary photobiological and genetic analysis of the sob1-D mutant, we hypothesized that OBP3 is a transcription factor involved in both phytochrome and cryptochrome-mediated signal transduction. In addition, we hypothesized that OBP3 is involved in auxin signaling and root development. Based on our preliminary photobiological and genetic analysis of the sob2-D mutant, we also hypothesized that a related gene, LEP, is involved in hormone signaling and seedling development.

Neff, Michael M.

2011-06-23

48

TNF-induced beta2 integrin activation involves Src kinases and a redox-regulated activation of p38 MAPK.  

PubMed

We previously demonstrated that the TNF-alpha-induced inside-out signaling leading to beta(2) integrin activation is redox regulated. To identify kinases involved in this pathway, the effects of kinase inhibitors on the expression of beta(2) integrin activation neoepitope (clone 24) were investigated. We show that both p38 MAPK (inhibited by SB203580) and Src kinases (inhibited by PP2) are involved in beta(2) integrin activation by TNF and oxidants in human neutrophils. Src kinases appeared constitutively active in resting neutrophils and not further activated by TNF or oxidants in nonadherent conditions. However, PP2 blocked both TNF-induced expression of the 24 epitope and cell adhesion promoted by the integrin activating anti-CD18 KIM185 mAb, showing that both the inside-out and the outside-in signaling involve Src kinases. p38 MAPK was activated by TNF and oxidants in nonadherent conditions i.e., with 10 mM EDTA. This activation in EDTA resulted in CD11b, CD35 and CD66 up-regulation and in an oxidative response, all blocked by SB203580 and PP2. p38 MAPK was not activated upon direct integrin activation by KIM185 mAb. Thus, p38 activation allows the study to distinguish the initial transduction pathway leading to beta(2) integrin activation from the signaling resulting from integrin engagement. Finally, p38 MAPK activation by TNF was blocked by diphenylene iodonium, an inhibitor of flavoprotein oxidoreductase, and by the free radical scavenger N-acetylcystein. Taken together, these results demonstrate, for the first time, that constitutively activated Src tyrosine kinases and a redox-regulated activation of p38 MAPK are involved in TNF inside-out signaling leading to beta(2) integrin activation. PMID:15240725

Bouaouina, Mohamed; Blouin, Eric; Halbwachs-Mecarelli, Lise; Lesavre, Philippe; Rieu, Philippe

2004-07-15

49

Predicting involvement in prison gang activity: Street gang membership, social and psychological factors.  

PubMed

The aim of this study was to examine whether street gang membership, psychological factors, and social factors such as preprison experiences could predict young offenders' involvement in prison gang activity. Data were collected via individual interviews with 188 young offenders held in a Young Offenders Institution in the United Kingdom. Results showed that psychological factors such as the value individuals attached to social status, a social dominance orientation, and antiauthority attitudes were important in predicting young offenders' involvement in prison gang activity. Further important predictors included preimprisonment events such as levels of threat, levels of individual delinquency, and levels of involvement in group crime. Longer current sentences also predicted involvement in prison gang activity. However, street gang membership was not an important predictor of involvement in prison gang activity. These findings have implications for identifying prisoners involved in prison gang activity and for considering the role of psychological factors and group processes in gang research. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24127897

Wood, Jane L; Alleyne, Emma; Mozova, Katarina; James, Mark

2014-06-01

50

Premature aging in mice activates a systemic metabolic response involving autophagy induction  

Microsoft Academic Search

Autophagy is a highly regulated intracellular process involved in the turnover of most cellular constituents and in the maintenance of cellular homeostasis. It is well-established that the basal autophagic activity of living cells decreases with age, thus contributing to the accumulation of damaged macromolecules during aging. Conversely, the activity of this catabolic pathway is required for lifespan extension in animal

G. Mariño; Alejandro P. Ugalde; Natalia Salvador-Montoliu; Ignacio Varela; P. M. Quirós; J. Cadiñanos; Pluijm van der I; J. M. P. Freije; C. López-Otín

2008-01-01

51

Longitudinal modeling of adolescents' activity involvement, problem peer associations, and youth smoking  

Microsoft Academic Search

Longitudinal associations among different types of organized activity involvement, problem peer associations, and cigarette smoking were examined in a sample of 1040 adolescents (mean age = 15.62 at baseline, 16.89 at 15-month assessment, 17.59 at 24months) enriched for smoking experimentation (83% had tried smoking). A structural equation model tested longitudinal paths between three categories of involvement (team sports, school clubs

Aaron Metzger; Nickki Dawes; Robin Mermelstein; Lauren Wakschlag

2011-01-01

52

Involvement of cAMP Response Element-Binding Protein Activation in Salivary Secretion  

Microsoft Academic Search

Objective: Saliva secretion is mediated by cAMP and the calcium signaling pathway in salivary acinar cells. The PKA signaling pathway plays an important role in protein secretion through the activation of cAMP, in fluid secretion through the elevation of intracellular calcium and in the activation of cAMP response element-binding protein (CREB), which is involved in these signaling cascades. In this

Koichi Yamada; Hiroko Inoue; Satoshi Kida; Shoichi Masushige; Tatsuaki Nishiyama; Kenji Mishima; Ichiro Saito

2006-01-01

53

Carbohydrate in the mouth enhances activation of brain circuitry involved in motor performance and sensory perception.  

PubMed

The presence of carbohydrate in the human mouth has been associated with the facilitation of motor output and improvements in physical performance. Oral receptors have been identified as a potential mode of afferent transduction for this novel form of nutrient signalling that is distinct from taste. In the current study oral exposure to carbohydrate was combined with a motor task in a neuroimaging environment to identify areas of the brain involved in this phenomenon. A mouth-rinsing protocol was conducted whilst carbohydrate (CHO) and taste-matched placebo (PLA) solutions were delivered and recovered from the mouths of 10 healthy volunteers within a double-blind, counterbalanced design. This protocol eliminates post-oral factors and controls for the perceptual qualities of solutions. Functional magnetic resonance imaging of the brain was used to identify cortical areas responsive to oral carbohydrate during rest and activity phases of a hand-grip motor task. Mean blood-oxygen-level dependent signal change experienced in the contralateral primary sensorimotor cortex was larger for CHO compared with PLA during the motor task when contrasted with a control condition. Areas of activation associated with CHO exclusively were observed over the primary taste cortex and regions involved in visual perception. Regions in the limbic system associated with reward were also significantly more active with CHO. This is the first demonstration that oral carbohydrate signalling can increase activation within the primary sensorimotor cortex during physical activity and enhance activation of neural networks involved in sensory perception. PMID:24858834

Turner, Clare E; Byblow, Winston D; Stinear, Cathy M; Gant, Nicholas

2014-09-01

54

IEX-1: a new ERK substrate involved in both ERK survival activity and ERK activation.  

PubMed

IEX-1 is an early response and NF-kappaB target gene implicated in the regulation of cellular viability. We show here that IEX-1 is a substrate for ERKs and that IEX-1 and ERK regulate each other's activities. IEX-1 was isolated by phosphorylation screening with active ERK2 and found subsequently phosphorylated in vivo upon ERK activation. IEX-1 interacts with phosphorylated ERKs but not with c-jun N-terminal kinase (JNK) or p38. Upon phosphorylation by ERKs, IEX-1 acquires the ability to inhibit cell death induced by various stimuli. In turn, IEX-1 potentiates ERK activation in response to various growth factors. By using various IEX-1 mutants in which the ERK phosphoacceptor and/or ERK docking sites were mutated, we show that the IEX-1 pro-survival effect is dependent on its phosphorylation state but not on its ability to potentiate ERK activation. Conversely, IEX-1-induced modulation of ERK activation requires ERK-IEX-1 association but is independent of IEX-1 phosphorylation. Thus, IEX-1 is a new type of ERK substrate that has a dual role in ERK signaling by acting both as an ERK downstream effector mediating survival and as a regulator of ERK activation. PMID:12356731

Garcia, Josefina; Ye, Yunbin; Arranz, Valérie; Letourneux, Claire; Pezeron, Guillaume; Porteu, Françoise

2002-10-01

55

Streptokinase-induced platelet activation involves antistreptokinase antibodies and cleavage of protease-activated receptor-1.  

PubMed

Streptokinase activates platelets, limiting its effectiveness as a thrombolytic agent. The role of antistreptokinase antibodies and proteases in streptokinase-induced platelet activation was investigated. Streptokinase induced localization of human IgG to the platelet surface, platelet aggregation, and thromboxane A(2) production. These effects were inhibited by a monoclonal antibody to the platelet Fc receptor, IV.3. The platelet response to streptokinase was also blocked by an antibody directed against the cleavage site of the platelet thrombin receptor, protease-activated receptor-1 (PAR-1), but not by hirudin or an active site thrombin inhibitor, Ro46-6240. In plasma depleted of plasminogen, exogenous wild-type plasminogen, but not an inactive mutant protein, S(741)A plasminogen, supported platelet aggregation, suggesting that the protease cleaving PAR-1 was streptokinase-plasminogen. Streptokinase-plasminogen cleaved a synthetic peptide corresponding to PAR-1, resulting in generation of PAR-1 tethered ligand sequence and selectively reduced binding of a cleavage-sensitive PAR-1 antibody in intact cells. A combination of streptokinase, plasminogen, and antistreptokinase antibodies activated human erythroleukemic cells and was inhibited by pretreatment with IV.3 or pretreating the cells with the PAR-1 agonist SFLLRN, suggesting Fc receptor and PAR-1 interactions are necessary for cell activation in this system also. Streptokinase-induced platelet activation is dependent on both antistreptokinase-Fc receptor interactions and cleavage of PAR-1. (Blood. 2000;95:1301-1308) PMID:10666203

McRedmond, J P; Harriott, P; Walker, B; Fitzgerald, D J

2000-02-15

56

Structural Model of Employee Involvement in Skill Development Activity: The Role of Individual Differences  

ERIC Educational Resources Information Center

We extend prior research on involvement in employee development activity by including prominent individual difference constructs that have been previously ignored in this area of research. These include two important personality characteristics (conscientiousness and openness to experience), mental ability and goal orientation constructs. We…

Maurer, Todd J.; Lippstreu, Michael; Judge, Timothy A.

2008-01-01

57

Longitudinal Modeling of Adolescents' Activity Involvement, Problem Peer Associations, and Youth Smoking  

ERIC Educational Resources Information Center

Longitudinal associations among different types of organized activity involvement, problem peer associations, and cigarette smoking were examined in a sample of 1040 adolescents (mean age = 15.62 at baseline, 16.89 at 15-month assessment, 17.59 at 24 months) enriched for smoking experimentation (83% had tried smoking). A structural equation model…

Metzger, Aaron; Dawes, Nickki; Mermelstein, Robin; Wakschlag, Lauren

2011-01-01

58

Perceived community environment and physical activity involvement in a northern-rural Aboriginal community  

Microsoft Academic Search

BACKGROUND: Type 2 diabetes disproportionately affects Aboriginal peoples in Canada. Ample evidence shows that regular physical activity (PA) plays an important role in the prevention and treatment of type 2 diabetes. Evidence is beginning to emerge linking PA to the physical environment but little is known about the relationship between remote rural environments and PA involvement in Aboriginal peoples. This

Allison M. Kirby; Lucie Lévesque; Virginia Wabano; Jennifer Robertson-Wilson

2007-01-01

59

Adult Work Motivation for Involvement in Shared Governance Activities among Faculty Senate Leaders.  

ERIC Educational Resources Information Center

Higher education institutions rely increasingly on their faculty to create, implement, and validate administrative decisions. As a result, the position of faculty governance body leader provides a meaningful example of the type of faculty member who becomes involved in campus activities outside the normal workload. This study examined the work…

Miller, Michael T.

60

An Emergent Language Program Framework: Actively Involving Learners in Needs Analysis.  

ERIC Educational Resources Information Center

Relates the experience of the staff of an aquaculture outreach program in Northeast Thailand in implementing an English for special purposes program. By actively involving learners in both the needs analysis and program design, teachers were able to adapt the program content to the requirements of the students. (15 references) (JL)

Savage, William; Storer, Graeme

1992-01-01

61

A Longitudinal Examination of Breadth and Intensity of Youth Activity Involvement and Successful Development  

ERIC Educational Resources Information Center

Connections between youth activity involvement and indicators of successful development were examined in a longitudinal high school sample. Drawing on theories of expertise skill development (e.g., J. Cote, 1999); the selection, optimization, and compensation framework (P. B. Baltes, 1997); and theories of positive youth development (e.g., R. M.…

Busseri, Michael A.; Rose-Krasnor, Linda; Willoughby, Teena; Chalmers, Heather

2006-01-01

62

Involving Your Child or Teen with ASD in Integrated Community Activities  

ERIC Educational Resources Information Center

Participating in outside activities and community-based endeavors can be tricky for people with special needs, like Autism Spectrum Disorder (ASD). Families meet more than a few obstacles attempting to integrate their children or teens who have special needs like ASD. Most typical children are highly involved in sports, clubs and camps. If a…

McKee, Rebecca

2011-01-01

63

Calanquinone A induces anti-glioblastoma activity through glutathione-involved DNA damage and AMPK activation.  

PubMed

Glioblastoma, a highly malignant glioma, is resistant to both radiation and chemotherapy and is an intractable problem in clinical treatment. New therapeutic approaches are in urgent need. Calanquinone A, an herbal constituent, displayed anti-proliferative activity against glioblastoma cells, including A172, T98 and U87. Flow cytometric analysis showed an S phase arrest and a subsequent apoptosis to calanquinone A action. Further identification demonstrated a rapid increase of ?H2A.X formation at S phase. The data together with comet tail formation and Chk1 activation indicated DNA damage response. N-acetyl cysteine (an antioxidant and a glutathione precursor) and exogenously applied glutathione, but not trolox (an antioxidant), completely abolished calanquinone A-induced effects. Immunofluorescence assay revealed that calanquinone A decreased the intracellular glutathione levels in both A172 and T98 cells. However, calanquinone A, by itself, did not conjugate glutathione. The data suggested that the decrease of cellular glutathione predominantly contributed to the anticancer mechanism. Furthermore, calanquinone A induced the activation of AMP-activated protein kinase (AMPK) and the inhibition of p70S6K activity. Rhodamine efflux assay showed that calanquinone A did not block efflux activity, indicating that calanquinone A was not a P-glycoprotein substrate. In summary, the data suggest that calanquinone A displays anti-glioblastoma activity through a decrease of cellular glutathione levels that subsequently induces DNA damage stress and AMPK activation, leading to cell cycle arrest at S-phase and apoptotic cell death. Furthermore, calanquinone A does not serve as a P-glycoprotein substrate, suggesting a potential for further development in anti-glioblastoma therapy. PMID:24607408

Liu, Fan-Lun; Hsu, Jui-Ling; Lee, Yean-Jang; Dong, Yu-Shun; Kung, Fan-Lu; Chen, Ching-Shih; Guh, Jih-Hwa

2014-05-01

64

Nitric oxide is involved in abscisic acid-induced antioxidant activities in Stylosanthes guianensis.  

PubMed

Previous studies suggest that abscisic acid (ABA) stimulates the activities of antioxidant enzymes under normal and chilling temperature and enhanced chilling resistance in Stylosanthes guianensis. The objective of this study was to test whether nitric oxide (NO) is involved in the ABA-induced activities of the antioxidant enzymes in Stylosanthes guianensis due to its nature as a second messenger in stress responses. Plants were treated with NO donors, ABA, ABA in combination with NO scavengers or the nitric oxide synthase (NOS) inhibitor and their effects on the activity of antioxidant enzymes and NO production were compared. The results showed that ABA increased the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The effect of ABA on antioxidant enzyme activities was suppressed by the NOS inhibitor, N(omega)-nitro-L-arginine (L-NNA), and the NO scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl3-oxide (PTIO). NO content increased after 5 h of ABA treatment. The NO-scavenger, PTIO, and the NOS-inhibitor, L-NNA, inhibited the accumulation of NO in ABA-treated Stylosanthes guianensis. NO donor treatment enhanced the activities of SOD, CAT, and APX. The results suggested that NO was involved in the ABA-induced activities of SOD, CAT, and APX in Stylosanthes guianensis. ABA triggered NO production that may lead to the stimulation of antioxidant enzyme activities. PMID:16263901

Zhou, Biyan; Guo, Zhenfei; Xing, Jinpeng; Huang, Bingru

2005-12-01

65

Activation of Human Neutrophil Procollagenase by Nitrogen Dioxide and Peroxynitrite: A Novel Mechanism for Procollagenase Activation Involving Nitric Oxide  

Microsoft Academic Search

The involvement of nitric oxide (NO) and its reactive intermediates such as nitrogen dioxide (NO2) and peroxynitrite (ONOO?) in the activation of matrix metalloproteinase was investigated. The human neutrophil procollagenase (matrix metalloproteinase-8) (Mr, 85 kDa) was purified to homogeneity from human neutrophils by using column chromatography. After incubation of human neutrophil procollagenase with various nitrogen oxide-generating systems, collagenolytic activity in

Tatsuya Okamoto; Takaaki Akaike; Tetsuo Nagano; Seiya Miyajima; Moritaka Suga; Masayuki Ando; Koji Ichimori; Hiroshi Maeda

1997-01-01

66

Active demethylation in mouse zygotes involves cytosine deamination and base excision repair  

PubMed Central

Background DNA methylation in mammals is an epigenetic mark necessary for normal embryogenesis. During development active loss of methylation occurs in the male pronucleus during the first cell cycle after fertilisation. This is accompanied by major chromatin remodelling and generates a marked asymmetry between the paternal and maternal genomes. The mechanism(s) by which this is achieved implicate, among others, base excision repair (BER) components and more recently a major role for TET3 hydroxylase. To investigate these methylation dynamics further we have analysed DNA methylation and hydroxymethylation in fertilised mouse oocytes by indirect immunofluorescence (IF) and evaluated the relative contribution of different candidate factors for active demethylation in knock-out zygotes by three-dimensional imaging and IF semi-quantification. Results We find two distinct phases of loss of paternal methylation in the zygote, one prior to and another coincident with, but not dependent on, DNA replication. TET3-mediated hydroxymethylation is limited to the replication associated second phase of demethylation. Analysis of cytosine deaminase (AID) null fertilised oocytes revealed a role for this enzyme in the second phase of loss of paternal methylation, which is independent from hydroxymethylation. Investigation into the possible repair pathways involved supports a role for AID-mediated cytosine deamination with subsequent U-G mismatch long-patch BER by UNG2 while no evidence could be found for an involvement of TDG. Conclusions There are two observable phases of DNA demethylation in the mouse zygote, before and coincident with DNA replication. TET3 is only involved in the second phase of loss of methylation. Cytosine deamination and long-patch BER mediated by UNG2 appear to independently contribute to this second phase of active demethylation. Further work will be necessary to elucidate the mechanism(s) involved in the first phase of active demethylation that will potentially involve activities required for early sperm chromatin remodelling.

2013-01-01

67

Involvement of prostaglandins in LPS-mediated regulation of plasminogen activator synthesis by inflammatory macrophages.  

PubMed

We have previously shown that production of plasminogen activator by inflammatory macrophages can be inhibited by immunomodulators of bacterial origin, especially LPS. In these experiments, the contribution of prostaglandins to this control was investigated. We examined the effect of two prostaglandin synthetase blockers, indomethacin and diclofenac. These drugs do not modify per se the production of plasminogen activator but they can partially prevent the inhibitory effect of LPS. Since restoration was not complete when plasminogen activator production was strongly inhibited, it is suggested that the immunomodulator acts through a mechanism involving more than one pathway only one of which would be mediated by prostaglandins. PMID:6434442

Drapier, J C; Petit, J F

1984-01-01

68

Prohibitin is involved in the activated internalization and degradation of protease-activated receptor 1.  

PubMed

The protease-activated receptor 1 (PAR1) is a G-protein-coupled receptor that is irreversibly activated by either thrombin or metalloprotease 1. Due this irrevocable activation, activated internalization and degradation are critical for PAR1 signaling termination. Prohibitin (PHB) is an evolutionarily conserved, ubiquitously expressed, pleiotropic protein and belongs to the stomatin/prohibitin/flotillin/HflK/C (SPFH) domain family. In a previous study, we found that PHB localized on the platelet membrane and participated in PAR1-mediated human platelet aggregation, suggesting that PHB likely regulates the signaling of PAR1. Unfortunately, PHB's exact function in PAR1 internalization and degradation is unclear. In the current study, flow cytometry revealed that PHB expressed on the surface of endothelial cells (HUVECs) but not cancer cells (MDA-MB-231). Further confocal microscopy revealed that PHB dynamically associates with PAR1 in a time-dependent manner following induction with PAR1-activated peptide (PAR1-AP), though differently between HUVECs and MDA-MB-231 cells. Depletion of PHB by RNA interference significantly inhibited PAR1 activated internalization and led to sustained Erk1/2 phosphorylation in the HUVECs; however, a similar effect was not observed in MDA-MB-231 cells. For both the endothelial and cancel cells, PHB repressed PAR1 degradation, while knockdown of PHB led to increased PAR1 degradation, and PHB overexpression inhibited PAR1 degradation. These results suggest that persistent PAR1 signaling due to the absence of membrane PHB and decreased PAR1 degradation caused by the upregulation of intracellular PHB in cancer cells (such as MDA-MB-231 cells) may render cells highly invasive. As such, PHB may be a novel target in future anti-cancer therapeutics, or in more refined cancer malignancy diagnostics. PMID:24732013

Wang, Yan-Jie; Guo, Xiao-Long; Li, Sheng-An; Zhao, Yu-Qi; Liu, Zi-Chao; Lee, Wen-Hui; Xiang, Yang; Zhang, Yun

2014-07-01

69

Oclacitinib (APOQUEL(®) ) is a novel Janus kinase inhibitor with activity against cytokines involved in allergy.  

PubMed

Janus kinase (JAK) enzymes are involved in cell signaling pathways activated by various cytokines dysregulated in allergy. The objective of this study was to determine whether the novel JAK inhibitor oclacitinib could reduce the activity of cytokines implicated in canine allergic skin disease. Using isolated enzyme systems and in vitro human or canine cell models, potency and selectivity of oclacitinib was determined against JAK family members and cytokines that trigger JAK activation in cells. Oclacitinib inhibited JAK family members by 50% at concentrations (IC50 's) ranging from 10 to 99 nm and did not inhibit a panel of 38 non-JAK kinases (IC50 's > 1000 nm). Oclacitinib was most potent at inhibiting JAK1 (IC50  = 10 nm). Oclacitinib also inhibited the function of JAK1-dependent cytokines involved in allergy and inflammation (IL-2, IL-4, IL-6, and IL-13) as well as pruritus (IL-31) at IC50 's ranging from 36 to 249 nm. Oclacitinib had minimal effects on cytokines that did not activate the JAK1 enzyme in cells (erythropoietin, granulocyte/macrophage colony-stimulating factor, IL-12, IL-23; IC50 's > 1000 nm). These results demonstrate that oclacitinib is a targeted therapy that selectively inhibits JAK1-dependent cytokines involved in allergy, inflammation, and pruritus and suggests these are the mechanisms by which oclacitinib effectively controls clinical signs associated with allergic skin disease in dogs. PMID:24495176

Gonzales, A J; Bowman, J W; Fici, G J; Zhang, M; Mann, D W; Mitton-Fry, M

2014-08-01

70

Mechanism of IL-1? modulation of intestinal epithelial barrier involves p38 kinase and activating transcription factor-2 activation.  

PubMed

The defective intestinal epithelial tight junction (TJ) barrier has been postulated to be an important pathogenic factor contributing to intestinal inflammation. It has been shown that the proinflammatory cytokine IL-1? causes an increase in intestinal permeability; however, the signaling pathways and the molecular mechanisms involved remain unclear. The major purpose of this study was to investigate the role of the p38 kinase pathway and the molecular processes involved. In these studies, the in vitro intestinal epithelial model system (Caco-2 monolayers) was used to delineate the cellular and molecular mechanisms, and a complementary in vivo mouse model system (intestinal perfusion) was used to assess the in vivo relevance of the in vitro findings. Our data indicated that the IL-1? increase in Caco-2 TJ permeability correlated with an activation of p38 kinase. The activation of p38 kinase caused phosphorylation and activation of p38 kinase substrate, activating transcription factor (ATF)-2. The activated ATF-2 translocated to the nucleus where it attached to its binding motif on the myosin L chain kinase (MLCK) promoter region, leading to the activation of MLCK promoter activity and gene transcription. Small interfering RNA induced silencing of ATF-2, or mutation of the ATF-2 binding motif prevented the activation of MLCK promoter and MLCK mRNA transcription. Additionally, in vivo intestinal perfusion studies also indicated that the IL-1? increase in mouse intestinal permeability required p38 kinase-dependent activation of ATF-2. In conclusion, these studies show that the IL-1?-induced increase in intestinal TJ permeability in vitro and in vivo was regulated by p38 kinase activation of ATF-2 and by ATF-2 regulation of MLCK gene activity. PMID:23656735

Al-Sadi, Rana; Guo, Shuhong; Ye, Dongmei; Dokladny, Karol; Alhmoud, Tarik; Ereifej, Lisa; Said, Hamid M; Ma, Thomas Y

2013-06-15

71

EMERGING ADULTS' TREATMENT OUTCOMES IN RELATION TO 12-STEP MUTUAL-HELP ATTENDANCE AND ACTIVE INVOLVEMENT  

PubMed Central

Background Participation in Alcoholics Anonymous (AA) and Narcotics Anonymous (NA) during and following treatment has been found to confer recovery-related benefit among adults and adolescents, but little is known about emerging adults (18–24yrs). This transitional life-stage is distinctive for greater distress, higher density of psychopathology, and poorer treatment and continuing care compliance. Greater knowledge would inform the utility of treatment referrals to 12-step organizations for this age-group. Methods Emerging adults (N=303; 18–24yrs; 26% female; 95% White; 51% comorbid [SCID-derived] axis I disorders) enrolled in a naturalistic study of residential treatment effectiveness assessed at intake, 3, 6, and 12 months on 12-step attendance and involvement and treatment outcomes (Percent Days Abstinent [PDA]; Percent Days Heavy Drinking [PDHD]). Lagged hierarchical linear models (HLMs) tested whether attendance and involvement conferred recovery benefits, controlling for a variety of confounds. Results The percentage attending 12-step meetings prior to treatment (36%) rose sharply at 3months (89%), was maintained at 6 months (82%), but declined at 12 months (76%). Average attendance peaked at about 3 times per week at 3 months dropping to just over once per week at 12 months. Initially high, but similarly diminishing, levels of active 12-step involvement were also observed. Lagged HLMs found beneficial effects for attendance, but stronger effects, which increased over time, for active involvement. Several active 12-step involvement indices were associated individually with outcome benefits. Conclusions Ubiquitous 12-step organizations may provide a supportive recovery context for this high-risk population at a developmental stage where non-using/sober peers are at a premium.

Kelly, John F.; Stout, Robert L.; Slaymaker, Valerie

2012-01-01

72

Involvement of mitogen-activated protein kinase signalling in pearl millet-downy mildew interaction.  

PubMed

Mitogen-activated protein kinase (MAPK) cascade-mediated signalling is essential in the establishment of resistance towards pathogens. The present study compared MAPK activities in a compatible and incompatible interaction between pearl millet [Pennisetum glaucum (L.) R. Br.] and downy mildew pathogen Sclerospora graminicola. Differential expression was observed with rapid and increased activation of MAPKs, PgMPK1 (48kDa) and PgMPK2 (44kDa), in the incompatible interaction; with a weak activity of only PgMPK1 in the compatible interaction. Immunoblot analysis showed PgMPK1 and PgMPK2 to be orthologs of salicylic acid-induced protein kinase and wound-induced protein kinase, respectively. Immunocytochemical analysis revealed pathogen-induced accumulation and nuclear localisation of PgMPKs only in the incompatible interaction with highest signals in the vascular tissues. Maximum PgMPKs activation correlated with the activation of several defence-related enzymes. In addition, inhibition of MAPK-activation by kinase cascade inhibitors correlated with the suppression of defence-related enzyme activities and pathogen-induced H2O2 accumulation. Treatment of pearl millet seedlings with abiotic and biotic elicitors led to a strong early induction of only PgMPK1. ?-Amino butyric acid and H2O2 were found to be best activators of PgMPK1. These results suggest that in pearl millet MAPK signalling is involved in mediating several defence mechanisms in response to pathogen infection. PMID:24268161

Melvin, Prasad; Prabhu, Sreedhara Ashok; Anup, Chandra Pal; Shailasree, Sekhar; Shetty, Huntrike Shekar; Kini, Kukkundoor Ramachandra

2014-01-01

73

Factors Involved in Iranian Women Heads of Household's Health Promotion Activities: A Grounded Theory Study.  

PubMed

We aimed to explore and describe the factors involved in Iranian women heads of household's health promotion activities. Grounded theory was used as the method. Sixteen women heads of household were recruited. Data were generated by semi structured interviews. Our findings indicated that remainder of resources (money, time and energy) alongside perceived severity of health risk were two main factors whereas women's personal and socio-economic characteristics were two contextual factors involved in these women's health promotion activities. To help these women improve their health status, we recommended that the government, non-governmental organizations and health care professionals provide them with required resources and increase their knowledge by holding training sessions. PMID:24039645

Rafii, Forough; Seyedfatemi, Naima; Rezaei, Mahboubeh

2013-01-01

74

Luteinizing Hormone Signaling in Preovulatory Follicles Involves Early Activation of the Epidermal Growth Factor Receptor Pathway  

PubMed Central

LH activates a cascade of signaling events that are propagated throughout the ovarian preovulatory follicle to promote ovulation of a mature egg. Critical to LH-induced ovulation is the induction of epidermal growth factor (EGF)-like growth factors and transactivation of EGF receptor (EGFR) signaling. Because the timing of this transactivation has not been well characterized, we investigated the dynamics of LH regulation of the EGF network in cultured follicles. Preovulatory follicles were cultured with or without recombinant LH and/or specific inhibitors. EGFR and MAPK phosphorylation were examined by immunoprecipitation and Western blot analyses. By semiquantitative RT-PCR, increases in amphiregulin and epiregulin mRNAs were detected 30 min after recombinant LH stimulation of follicles and were maximal after 2 h. LH-induced EGFR phosphorylation also increased after 30 min and reached a maximum at 2 h. EGFR activation precedes oocyte maturation and is cAMP dependent, because forskolin similarly activated EGFR. LH-induced EGFR phosphorylation was sensitive to AG1478, an EGFR kinase inhibitor, and to inhibitors of matrix metalloproteases GM6001 and TNF? protease inhibitor-1 (TAPI-1), suggesting the involvement of EGF-like growth factor shedding. LH- but not amphiregulin-induced oocyte maturation and EGFR phosphorylation were sensitive to protein synthesis inhibition. When granulosa cells were cultured with a combination of neutralizing antibodies against amphiregulin, epiregulin, and betacellulin, EGFR phosphorylation and MAPK activation were inhibited. In cultured follicles, LH-induced MAPK activation was partially inhibited by AG1478 and GM6001, indicating that this pathway is regulated in part by the EGF network but also involves additional pathways. Thus, complex mechanisms are involved in the rapid amplification and propagation of the LH signal within preovulatory follicles and include the early activation of the EGF network.

Panigone, Sara; Hsieh, Minnie; Fu, Maoyong; Persani, Luca; Conti, Marco

2008-01-01

75

Labdane diterpenes protect against anoxia\\/reperfusion injury in cardiomyocytes: involvement of AKT activation  

Microsoft Academic Search

Several labdane diterpenes exert anti-inflammatory and cytoprotective actions; therefore, we have investigated whether these molecules protect cardiomyocytes in an anoxia\\/reperfusion (A\\/R) model, establishing the molecular mechanisms involved in the process. The cardioprotective activity of three diterpenes (T1, T2 and T3) was studied in the H9c2 cell line and in isolated rat cardiomyocyte subjected to A\\/R injury. In both cases, treatment

I Cuadrado; M Fernández-Velasco; L Boscá; B de las Heras

2011-01-01

76

Activity and recovery cycles of National Rugby League matches involving higher and lower ranked teams.  

PubMed

This study investigated the influence of ladder position on ball-in-play and recovery periods in elite National Rugby League (NRL) competitive matches. Video recordings of 192 NRL matches and 18 NRL finals matches played over 2 competitive seasons were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, whereas any stoppages during the match (e.g., for scrums, penalties, line drop outs, tries, and video referee decisions) were considered recovery. In comparison to matches involving lower standard teams, there was a greater proportion (effect size [ES] = 0.37-0.67) of long duration (>91 seconds) and a smaller proportion (ES = 0.49-0.68) of short duration (<45 seconds) ball-in-play periods when Top 4 teams were competing against other Top 4 teams. No meaningful differences were found between teams of different ladder positions for the proportion of short (ES = 0.04-0.16) and long (ES = 0.06-0.28) recovery periods. In comparison to fixture matches involving the top 4 teams, finals matches had a smaller proportion (ES = 0.56) of long duration activity periods, and a greater proportion (ES = 0.54) of short duration activity periods. Only small differences were found between finals matches and matches involving the Top 4 teams for the proportion of short (ES = 0.42) and long (ES = 0.41) recovery periods. These findings suggest that the competitive advantage of the best NRL teams is closely linked to their ability to maintain a higher playing intensity than less successful teams. Furthermore, long ball-in-play periods in high-standard fixture matches (i.e., involving the top 4 teams) ensure that players are adequately prepared for the ball-in-play demands of finals matches. PMID:23037615

Gabbett, Tim J

2013-06-01

77

Fatty acid transport and activation and the expression patterns of genes involved in fatty acid trafficking  

Microsoft Academic Search

These studies defined the expression patterns of genes involved in fatty acid transport, activation and trafficking using quantitative PCR (qPCR) and established the kinetic constants of fatty acid transport in an effort to define whether vectorial acylation represents a common mechanism in different cell types (3T3-L1 fibroblasts and adipocytes, Caco-2 and HepG2 cells and three endothelial cell lines (b-END3, HAEC,

Angel Sandoval; Peter Fraisl; Elsa Arias-Barrau; Concetta C. DiRusso; Diane Singer; Whitney Sealls; Paul N. Black

2008-01-01

78

UV-induced activation of AP-1 involves obligatory extranuclear steps including Raf-1 kinase.  

PubMed Central

Irradiation of cells with ultraviolet light (UV) leads to modifications of c-Jun resembling those elicited by phorbol esters or oncogenes, and to enhanced transcription of AP-1-dependent genes. The UV-induced signal also triggers activation of Raf-1 and MAP-2 kinases. A dominant-negative Raf-1 kinase mutant strongly interferes with both phorbol ester and UV-induced AP-1 activation, indicating obligatory involvement of identical components in cytoplasmic signal transduction. Thus, from a presumably nuclear site of energy absorption, a signal needs to be transmitted to the cytoplasm in order to achieve activation of a nuclear transcription factor. Further, signals elicited from different primary sites merge prior to or at the level of activation of Raf-1 kinase. Images

Radler-Pohl, A; Sachsenmaier, C; Gebel, S; Auer, H P; Bruder, J T; Rapp, U; Angel, P; Rahmsdorf, H J; Herrlich, P

1993-01-01

79

UV-induced activation of AP-1 involves obligatory extranuclear steps including Raf-1 kinase.  

PubMed

Irradiation of cells with ultraviolet light (UV) leads to modifications of c-Jun resembling those elicited by phorbol esters or oncogenes, and to enhanced transcription of AP-1-dependent genes. The UV-induced signal also triggers activation of Raf-1 and MAP-2 kinases. A dominant-negative Raf-1 kinase mutant strongly interferes with both phorbol ester and UV-induced AP-1 activation, indicating obligatory involvement of identical components in cytoplasmic signal transduction. Thus, from a presumably nuclear site of energy absorption, a signal needs to be transmitted to the cytoplasm in order to achieve activation of a nuclear transcription factor. Further, signals elicited from different primary sites merge prior to or at the level of activation of Raf-1 kinase. PMID:8384549

Radler-Pohl, A; Sachsenmaier, C; Gebel, S; Auer, H P; Bruder, J T; Rapp, U; Angel, P; Rahmsdorf, H J; Herrlich, P

1993-03-01

80

Insulin and dexamethasone stimulation of cardiac lipoprotein lipase activity involves the actin-based cytoskeleton.  

PubMed Central

Lipoprotein lipase (LPL) activity in cultured ventricular cardiomyocytes from adult rat hearts was stimulated by the combination of insulin (100 nM) and dexamethasone (100 nM) during an overnight (16 h) incubation. Wortmannin (100 nM), rapamycin (30 ng/ml) or PD98059 (50 microM) did not prevent this stimulation, suggesting that phosphatidylinositol 3-kinase, p70 S6 kinase and the mitogen-activated protein kinase cascade are not involved in transducing the hormonal signal. In contrast, cytochalasin D (2 microM) completely abolished the stimulatory effect of insulin and dexamethasone on both heparin-releasable LPL and total cellular LPL activities. The potential role of the actin cytoskeleton in the stimulation of LPL activity by insulin and dexamethasone appears to be distal to the initial signalling events since cytochalasin D is still effective in preventing the stimulation when added 2 h after the hormones.

Ewart, H S; Severson, D L

1999-01-01

81

Determination of catalase activity using chromogenic probe involving iso-nicotinicacidhydrazide and pyrocatechol.  

PubMed

A biocatalatic pathway involving chromogenic probe has been proposed for the determination of catalase activity by means of iso-nicotinicacidhydrazide (INH) and pyrocatechol (PC). The assay is based on the enzymatic consumption of hydrogen peroxide using INH-PC system. The response of the catalase activity was ascertained by the rate of the reaction involving 14.10mM H(2)O(2). On addition of H(2)O(2), INH-PC indicator system formed a chromogenic product with absorbance maxima at 490 nm. Hence the activity of catalase was directly measured by the chromogenic response in the formation of the coupled product. The catalase assay was elaborated by the kinetic response of the INH-PC system. The linearity of the catalase activity and H(2)O(2) was in the range 0.2-7.0 units and 1.76-7.0mM, respectively in 3 ml solution. The catalytic efficiency and catalytic power were calculated. The Michaelis-Menten constant of INH, PC and H(2)O(2) were found to be 0.344, 0.176 and 8.82 mM, respectively. The indicator reaction was applied in the determination of catalase activity in mycelia mats and culture media. PMID:21839122

Shivakumar, Anantharaman; Nagaraja, Padmarajaiah; Chamaraja, Nelligere Arkeshwaraiah; Krishna, Honnur; Avinash, Krishnegowda

2011-10-10

82

Aluminum Hydroxide Adjuvant Differentially Activates the Three Complement Pathways with Major Involvement of the Alternative Pathway  

PubMed Central

Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg2+. We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance.

Guven, Esin; Duus, Karen; Laursen, Inga; H?jrup, Peter; Houen, Gunnar

2013-01-01

83

Enterobacter-Activated Mosquito Immune Responses to Plasmodium Involve Activation of SRPN6 in Anopheles stephensi  

PubMed Central

Successful development of Plasmodium in the mosquito is essential for the transmission of malaria. A major bottleneck in parasite numbers occurs during midgut invasion, partly as a consequence of the complex interactions between the endogenous microbiota and the mosquito immune response. We previously identified SRPN6 as an immune component which restricts Plasmodium berghei development in the mosquito. Here we demonstrate that SRPN6 is differentially activated by bacteria in Anopheles stephensi, but only when bacteria exposure occurs on the lumenal surface of the midgut epithelium. Our data indicate that AsSRPN6 is strongly induced following exposure to Enterobacter cloacae, a common component of the mosquito midgut microbiota. We conclude that AsSRPN6 is a vital component of the E. cloacae-mediated immune response that restricts Plasmodium development in the mosquito An. stephensi.

Jacobs-Lorena, Marcelo

2013-01-01

84

Enterobacter-activated mosquito immune responses to Plasmodium involve activation of SRPN6 in Anopheles stephensi.  

PubMed

Successful development of Plasmodium in the mosquito is essential for the transmission of malaria. A major bottleneck in parasite numbers occurs during midgut invasion, partly as a consequence of the complex interactions between the endogenous microbiota and the mosquito immune response. We previously identified SRPN6 as an immune component which restricts Plasmodium berghei development in the mosquito. Here we demonstrate that SRPN6 is differentially activated by bacteria in Anopheles stephensi, but only when bacteria exposure occurs on the lumenal surface of the midgut epithelium. Our data indicate that AsSRPN6 is strongly induced following exposure to Enterobacter cloacae, a common component of the mosquito midgut microbiota. We conclude that AsSRPN6 is a vital component of the E. cloacae-mediated immune response that restricts Plasmodium development in the mosquito An. stephensi. PMID:23658788

Eappen, Abraham G; Smith, Ryan C; Jacobs-Lorena, Marcelo

2013-01-01

85

SPECT assessment of brain activation induced by caffeine: no effect on areas involved in dependence  

PubMed Central

Caffeine is not considered addictive, and in animals it does not trigger metabolic increases or dopamine release in brain areas involved in reinforcement and reward. Our objective was to measure caffeine effects on cerebral perfusion in humans using single photon emission computed tomography, with a specific focus on areas of reinforcement and reward. Two groups of nonsmoking subjects were studied, one with a low (8 subjects) and one with a high (6 subjects) daily coffee consumption. The subjects ingested 3 mg/kg caffeine or placebo in a raspberry-tasting drink, and scans were performed 45 min after ingestion. A control group of 12 healthy volunteers receiving no drink was also studied. Caffeine consumption led to a generalized, statistically nonsignificant perfusion decrease of 6% to 8%, comparable in low and high consumers. Compared with controls, low consumers displayed neuronal activation bilaterally in inferior frontal gyrusanterior insular cortex and uncus, left internal parietal cortex, right lingual gyrus, and cerebellum. In high consumers, brain activation occurred bilaterally only in hypothalamus. Thus, on a background of widespread low-amplitude perfusion decrease, caffeine activates a few regions mainly involved in the control of vigilance, anxiety, and cardiovascular regulation, but does not affect areas involved in reinforcing and reward.

Nehlig, Astrid; Armspach, Jean-Paul; Namer, Izzie J.

2010-01-01

86

HTLV-1 Tax-mediated TAK1 activation involves TAB2 adapter protein  

SciTech Connect

Human T cell leukemia virus type 1 (HTLV-1) Tax is an oncoprotein that plays a crucial role in the proliferation and transformation of HTLV-1-infected T lymphocytes. It has recently been reported that Tax activates a MAPKKK family, TAK1. However, the molecular mechanism of Tax-mediated TAK1 activation is not well understood. In this report, we investigated the role of TAK1-binding protein 2 (TAB2) in Tax-mediated TAK1 activation. We found that TAB2 physically interacts with Tax and augments Tax-induced NF-{kappa}B activity. Tax and TAB2 cooperatively activate TAK1 when they are coexpressed. Furthermore, TAK1 activation by Tax requires TAB2 binding as well as ubiquitination of Tax. We also found that the overexpression of TRAF2, 5, or 6 strongly induces Tax ubiquitination. These results suggest that TAB2 may be critically involved in Tax-mediated activation of TAK1 and that NF-{kappa}B-activating TRAF family proteins are potential cellular E3 ubiquitin ligases toward Tax.

Yu Qingsheng; Minoda, Yasumasa; Yoshida, Ryoko; Yoshida, Hideyuki [Division of Molecular and Cellular Immunology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582 (Japan); Iha, Hidekatsu [Department of Infectious Diseases, Faculty of Medicine, Oita University, Yufu, Oita 879-5593 (Japan); Kobayashi, Takashi; Yoshimura, Akihiko [Division of Molecular and Cellular Immunology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582 (Japan); Takaesu, Giichi [Division of Molecular and Cellular Immunology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582 (Japan)], E-mail: takaesug@bioreg.kyushu-u.ac.jp

2008-01-04

87

Involvement of cannabinoid receptor-1 activation in mitochondrial depolarizing effect of lipopolysaccharide in human spermatozoa.  

PubMed

Gram-negative bacteria frequently involved in urogenital tract infections release the endotoxin lipopolysaccharide (LPS); its receptor, toll-like receptor-4 (TLR4), has been recently identified in human spermatozoa, and its direct activation has been suggested in mediating adverse effects of LPS on human spermatozoa. However, the underlying signal transduction remains to be clarified. In other cell types, LPS induces the generation of endocannabinoids, which are involved in mediating endotoxin effects. In human spermatozoa, which exhibit a completely functional endocannabinoid system, the activation of cannabinoid receptor-1 (CB1) inhibited sperm mitochondrial membrane potential (??m). In this study, we tested the hypothesis of a contribution of CB1 activation by sperm-generated endocannabinoids in the adverse effects exerted by LPS on human spermatozoa. The exposure of motile sperm suspensions to E. coli LPS produced a significant decrease in sperm ??m, assessed at flow cytometry with JC-1, similar to that induced by Metanandamide (Met-AEA), a non-hydrolyzable analogue of the endocannabinoid AEA. The LPS-induced inhibition of ??m was prevented by the selective CB1 cannabinoid receptor antagonist, SR141716. However, the inhibition of ??m induced by either LPS or Met-AEA did not affect sperm motility. Consistent with this finding, the CB1-mediated inhibition of ??m was neither associated to mitochondrial generation of reactive oxygen species as evaluated by flow cytometry with MytoSox Red nor to apoptosis pathway activation as evaluated with cytoflorimetric assay for activated caspase-9 and caspase-3. Any oxidative genomic damage was also ruled out with the cytoflorimetric quantification of the oxidized base adduct 8-hydroxy-2'-deoxyguanosine. In conclusion, E. coli LPS inhibited sperm ??m through the activation of CB1, but this effect was not accompanied to the activation of mitochondrial dysfunction-related apoptotic/oxidative mechanisms, which could affect sperm motility and genomic integrity. PMID:24692267

Barbonetti, A; Vassallo, M R C; Costanzo, M; Battista, N; Maccarrone, M; Francavilla, S; Francavilla, F

2014-07-01

88

Antinociceptive Activity of Methanol Extract of Muntingia calabura Leaves and the Mechanisms of Action Involved.  

PubMed

Muntingia calabura L. (family Elaeocarpaceae) has been traditionally used to relieve various pain-related ailments. The present study aimed to determine the antinociceptive activity of methanol extract of M. calabura leaves (MEMC) and to elucidate the possible mechanism of antinociception involved. The in vivo chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-, serotonin-induced paw licking test) and thermal (hot plate test) models of nociception were used to evaluate the extract antinociceptive activity. The extract (100, 250, and 500?mg/kg) was administered orally 60?min prior to subjection to the respective test. The results obtained demonstrated that MEMC produced significant (P < 0.05) antinociceptive response in all the chemical- and thermal-induced nociception models, which was reversed after pretreatment with 5?mg/kg naloxone, a non-selective opioid antagonist. Furthermore, pretreatment with L-arginine (a nitric oxide (NO) donor), N(G)-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase (NOS)), methylene blue (MB; an inhibitor of cyclic-guanosine monophosphate (cGMP) pathway), or their combination also caused significant (P < 0.05) change in the intensity of the MEMC antinociception. In conclusion, the MEMC antinociceptive activity involves activation of the peripheral and central mechanisms, and modulation via, partly, the opioid receptors and NO/cGMP pathway. PMID:22611437

Sani, M H Mohd; Zakaria, Z A; Balan, T; Teh, L K; Salleh, M Z

2012-01-01

89

Involvement of the glycoproteic Ib-V-IX complex in nickel-induced platelet activation.  

PubMed Central

We studied the effect of nickel ions on platelet function because hypernickelemia has been found in patients with acute myocardial infarction. We previously demonstrated that nickel can activate an intracellular pathway leading to cytoskeleton reorganization consequent to tyrosine phosphorylation of p60(src) in human platelets independently of integrin alpha-IIb-beta(3). Moreover, in von Willebrand factor-stimulated platelets, the tyrosine phosphorylation of pp60(c-src) is closely associated with the activation of phosphatidylinositol 3-kinase (PIK), and two adhesion receptors, glycoprotein (Gp)Ib and GpIIb/IIIa(alpha-IIb-beta(3)), are involved. In our study, 1 and 5 mM nickel in the presence of fibrinogen induced platelet aggregation (independently of protein kinase C activation) and secretion. The pretreatment with a PIK inhibitor, wortmannin, strongly decreased nickel-induced platelet aggregation. Platelet treatment with mocarhagin, a cobra venom metalloproteinase that cleaves GpIba, significantly reduced aggregation induced by 5 mM without affecting the response to other agonists such as adenosine diphosphate (ADP). Moreover, nickel caused PIK translocation to the cytoskeleton. Taken together, these observations suggest a partial involvement of both integrins alpha-IIb-beta(3) and GpIb-V-IX complex in Ni(2+)-induced platelet activation.

Riondino, S; Pulcinelli, F M; Pignatelli, P; Gazzaniga, P P

2001-01-01

90

Involvement of the SATB1/F-actin complex in chromatin reorganization during active cell death  

PubMed Central

Over the past years, confirmations on the presence of actin and/or its polymerized form, F-actin, in the cell nucleus are progressively accumulating. Nevertheless, the function and localization of F-actin in the nucleus is still not fully characterized. Thus, the aim of the present study was to evaluate the association between F-actin and sequence-binding protein 1 (SATB1) and their involvement in chromatin remodeling associated with active cell death. Both SATB1 and F-actin were colocalized in the transcriptional active regions of the cell nucleus and a functional interaction was observed between SATB1 and higher-organized nuclear F-actin structures at the border between condensed and decondensed chromatin. These results extend the knowledge on the role of SATB1 and nuclear F-actin in three-dimensional chromatin organization and their functions during active cell death. Additionally, this study opens the discussion on the involvement of the SATB1/F-actin functional complex in active cell death; further studies are required to fully elucidate these issues.

GRZANKA, DARIUSZ; GAGAT, MACIEJ; IZDEBSKA, MAGDALENA

2014-01-01

91

Antinociceptive Activity of Methanol Extract of Muntingia calabura Leaves and the Mechanisms of Action Involved  

PubMed Central

Muntingia calabura L. (family Elaeocarpaceae) has been traditionally used to relieve various pain-related ailments. The present study aimed to determine the antinociceptive activity of methanol extract of M. calabura leaves (MEMC) and to elucidate the possible mechanism of antinociception involved. The in vivo chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-, serotonin-induced paw licking test) and thermal (hot plate test) models of nociception were used to evaluate the extract antinociceptive activity. The extract (100, 250, and 500?mg/kg) was administered orally 60?min prior to subjection to the respective test. The results obtained demonstrated that MEMC produced significant (P < 0.05) antinociceptive response in all the chemical- and thermal-induced nociception models, which was reversed after pretreatment with 5?mg/kg naloxone, a non-selective opioid antagonist. Furthermore, pretreatment with L-arginine (a nitric oxide (NO) donor), NG-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase (NOS)), methylene blue (MB; an inhibitor of cyclic-guanosine monophosphate (cGMP) pathway), or their combination also caused significant (P < 0.05) change in the intensity of the MEMC antinociception. In conclusion, the MEMC antinociceptive activity involves activation of the peripheral and central mechanisms, and modulation via, partly, the opioid receptors and NO/cGMP pathway.

Sani, M. H. Mohd.; Zakaria, Z. A.; Balan, T.; Teh, L. K.; Salleh, M. Z.

2012-01-01

92

DFT study of quercetin activated forms involved in antiradical, antioxidant, and prooxidant biological processes.  

PubMed

Quercetin, one of the most representative flavonoid compounds, is involved in antiradical, antioxidant, and prooxidant biological processes. Despite a constant increase of knowledge on both positive and negative activities of quercetin, it is unclear which activated form (quinone, semiquinone, or deprotonated) actually plays a role in each of these processes. Structural, electronic, and energetic characteristics of quercetin, as well as the influence of a copper ion on all of these parameters, are studied by means of quantum chemical electronic structure calculations. Introduction of thermodynamic cycles together with the role of coreactive compounds, such as reactive oxygen species, gives a glimpse of the most probable reaction schemes. Such a theoretical approach provides another hint to clarify which reaction is likely to occur within the broad range of quercetin biological activities. PMID:17263492

Fiorucci, Sébastien; Golebiowski, Jérôme; Cabrol-Bass, Daniel; Antonczak, Serge

2007-02-01

93

An Initial Investigation of Sexual Minority Youth Involvement in School-Based Extracurricular Activities  

PubMed Central

Sexual minority youth are at risk for negative school-based experiences and poor academic outcomes. Yet, little is known about their experiences in positive school-based contexts. Using the National Longitudinal Study of Adolescent Health (1,214 sexual minority and 11,427 heterosexual participants), this study compared participation rates in, predictors of, and outcomes associated with three types of school-based extracurricular activities - sports, arts, and school clubs - by sexual orientation and gender. Findings revealed several significant sexual orientation and gender differences in participation rates in school-based sports, clubs, and arts activities. Further, findings suggested that the outcomes associated with extracurricular activity involvement do not differ by sexual orientation and gender; however, predictors of participation in these domains varied across groups.

Russell, Stephen T.

2012-01-01

94

Activated alveolar macrophage and lymphocyte alveolitis in extrathoracic sarcoidosis without radiological mediastinopulmonary involvement  

SciTech Connect

Cellular characteristics of BAL were investigated in 18 patients with proved extrathoracic sarcoidosis (that is, sarcoidosis that affected the skin, eyes, parotid glands, stomach, nose, kidneys, or meninges) without clinical or radiological mediastinopulmonary involvement. Computed tomography of the thorax was performed on five patients: four patients were normal, and one had enlarged lymph nodes (these enlargements were not detectable on the patient's chest roentgenogram). The results of pulmonary function tests were normal in all patients. The total BAL cell count did not differ significantly between controls and patients. Abnormal percentages of alveolar lymphocytes (from 18 to 87%) were noted in 15 out of 18 patients. SACE levels were normal in 15 patients. No pulmonary gallium uptake was detected. The chemiluminescence of AM's, whether spontaneous or PMA induced, was increased in five out of seven patients. The percentages of T3+ lymphocytes in sarcoidosis patients did not significantly differ from those in controls. The T4+:T8+ ratio was normal in four patients and slightly increased in one. Follow-up of patients showed that alveolar lymphocytosis is as lasting as extrathoracic involvement. Our data demonstrate increased percentages of lymphocytes and activated AM's in the BAL of patients with extrathoracic sarcoidosis. This may be due to the initial involvement of the respiratory tract in extrathoracic sarcoidosis or to the diffusion of activated macrophages and lymphocytes from an extrathoracic site into the lung.

Wallaert, B.; Ramon, P.; Fournier, E.C.; Prin, L.; Tonnel, A.B.; Voisin, C.

1986-01-01

95

Involvement of Rac1 in Activation of Multicomponent Nox1- and Nox3-Based NADPH Oxidases  

PubMed Central

Several Nox family NADPH oxidases function as multicomponent enzyme systems. We explored determinants of assembly of the multicomponent oxidases Nox1 and Nox3 and examined the involvement of Rac1 in their regulation. Both enzymes are supported by p47phox and p67phox or homologous regulators called Noxo1 and Noxa1, although Nox3 is less dependent on these cofactors for activity. Plasma membrane targeting of Noxa1 depends on Noxo1, through tail-to-tail interactions between these proteins. Noxa1 can support Nox1 without Noxo1, when targeted to the plasma membrane by fusing membrane-binding sequences from Rac1 (amino acids 183 to 192) to the C terminus of Noxa1. However, membrane targeting of Noxa1 is not sufficient for activation of Nox1. Both the Noxo1-independent and -dependent Nox1 systems involve Rac1, since they are affected by Rac1 mutants or Noxa1 mutants defective in Rac binding or short interfering RNA-mediated Rac1 silencing. Nox1 or Nox3 expression promotes p22phox transport to the plasma membrane, and both oxidases are inhibited by mutations in the p22phox binding sites (SH3 domains) of the Nox organizers (p47phox or Noxo1). Regulation of Nox3 by Rac1 was also evident from the effects of mutant Rac1 or mutant Nox3 activators (p67phox or Noxa1) or Rac1 silencing. In the absence of Nox organizers, the Nox activators (p67phox or Noxa1) colocalize with Rac1 within ruffling membranes, independently of their ability to bind Rac1. Thus, Rac1 regulates both oxidases through the Nox activators, although it does not appear to direct the subcellular localization of these activators.

Ueyama, Takehiko; Geiszt, Miklos; Leto, Thomas L.

2006-01-01

96

Alternative activation of human plasmacytoid DCs in vitro and in melanoma lesions: involvement of LAG-3.  

PubMed

Plasmacytoid dendritic cells (pDCs) at tumor sites are often tolerogenic. Although pDCs initiate innate and adaptive immunity upon Toll-like receptor (TLR) triggering by pathogens, TLR-independent signals may be responsible for pDC activation and immune suppression in the tumor inflammatory environment. To identify molecules that are potentially involved in alternative pDC activation, we explored the expression and function of lymphocyte activation gene 3 (LAG-3) in human pDCs. In this report, we showed the expression of LAG-3 on the cell surface of a subset of circulating human pDCs. LAG-3+ pDCs exhibited a partially mature phenotype and were enriched at tumor sites in samples from melanoma patients. We found that LAG-3 interacted with major histocompatibility complex class II (MHC-II) to induce TLR-independent activation of pDCs with limited IFN? and enhanced IL-6 production. This in vitro cytokine profile of LAG-3-activated pDCs paralleled that of tumor-associated pDCs analyzed ex vivo. By confocal microscopy, LAG-3+ pDCs detected in melanoma-invaded lymph nodes (LNs) stained positive for IL-6 and preferentially localized near melanoma cells. These results suggest that LAG-3-mediated activation of pDCs takes place in vivo at tumor sites, and it is in part responsible for directing an immune-suppressive environment. PMID:24441096

Camisaschi, Chiara; De Filippo, Annamaria; Beretta, Valeria; Vergani, Barbara; Villa, Antonello; Vergani, Elisabetta; Santinami, Mario; Cabras, Antonello Domenico; Arienti, Flavio; Triebel, Frédéric; Rodolfo, Monica; Rivoltini, Licia; Castelli, Chiara

2014-07-01

97

The prevalence of, and factors associated with, serious crashes involving a distracting activity.  

PubMed

The study's objectives were to determine the prevalence and types of distracting activities involved in serious crashes, and to explore the factors associated with such crashes. We interviewed 1367 drivers who attended hospital in Perth, Western Australia between April 2002 and July 2004 following a crash. A structured questionnaire was administered to each driver and supplementary data were collected from ambulance and medical records. Over 30% of drivers (433, 31.7%) cited at least one distracting activity at the time of crashing and driver distraction was reported to have contributed to 13.6% of all crashes. The major distracting activities were conversing with passengers (155, 11.3%), lack of concentration (148, 10.8%) and outside factors (121, 8.9%). Using logistic regression, a distracting activity at the time of a crash was significantly more likely among drivers with shorter driving experience (0-9 years, 38.3% versus >or=30 years, 21.0%, p<0.001). Distracting activities at the time of serious crashes are common and can cause crashes, and the types of activities reported are varied. Increased driver awareness of the adverse consequences of distracted driving with a focus on novice drivers, enforcement of existing laws (e.g. those requiring a driver to maintain proper control of a vehicle), and progress on engineering initiatives (such as collision warning systems) are needed to reduce injury. PMID:17034748

McEvoy, Suzanne P; Stevenson, Mark R; Woodward, Mark

2007-05-01

98

Activated Hair Follicle Stem Cells and Wnt/?-catenin Signaling Involve in Pathnogenesis of Sebaceous Neoplasms  

PubMed Central

Sebaceous glands (SGs) undergo cyclic renewal independent of hair follicle stem cells (HFSCs) activation while HFSCs have the potential to differentiate into sebaceous gland cells, hair follicle and epidermal keratinocytes. Abnormalities of sebaceous gland progenitor cells contribute to the development of sebaceous neoplasms, but little is known about the role of HFSCs during sebaceous neoplasm development. Here, using dimethylbenzanthracene (DMBA) plus 12-o-tetradecanoyl phorbol-13-acetate (TPA) treatment developing sebaceous neoplasms (SNs) were identified with H&E and Oil red O staining. And then the molecular expression and activation of HFSCs and was characterized by immunostaining. Wnt10b/?-catenin signaling molecular which is important for activation of HFSCs were detected by immunostaining. We found hair follicle and epidermal cell markers were expressed in sebaceous neoplasms. Furthermore, SOX-9 and CD34-positive HFSCs were located in the basal layer of sebaceous lobules within the sebaceous neoplasms. Many appear to be in an active state. Finally, Wnt10b/?-catenin signaling was activated within the basal cells of sebaceous lobules in the sebaceous neoplasms. Collectively, our findings suggest that the abnormal activation of both HFSCs and Wnt10b/?-catenin signaling involves in the development of sebaceous neoplasms.

Qiu, Weiming; Lei, Mingxing; Li, Jin; Wang, Ning; Lian, Xiaohua

2014-01-01

99

Blockade of T-cell activation by dithiocarbamates involves novel mechanisms of inhibition of nuclear factor of activated T cells.  

PubMed Central

Dithiocarbamates (DTCs) have recently been reported as powerful inhibitors of NF-kappaB activation in a number of cell types. Given the role of this transcription factor in the regulation of gene expression in the inflammatory response, NF-kappaB inhibitors have been suggested as potential therapeutic drugs for inflammatory diseases. We show here that DTCs inhibited both interleukin 2 (IL-2) synthesis and membrane expression of antigens which are induced during T-cell activation. This inhibition, which occurred with a parallel activation of c-Jun transactivating functions and expression, was reflected by transfection experiments at the IL-2 promoter level, and involved not only the inhibition of NF-kappaB-driven reporter activation but also that of nuclear factor of activated T cells (NFAT). Accordingly, electrophoretic mobility shift assays (EMSAs) indicated that pyrrolidine DTC (PDTC) prevented NF-kappaB, and NFAT DNA-binding activity in T cells stimulated with either phorbol myristate acetate plus ionophore or antibodies against the CD3-T-cell receptor complex and simultaneously activated the binding of AP-1. Furthermore, PDTC differentially targeted both NFATp and NFATc family members, inhibiting the transactivation functions of NFATp and mRNA induction of NFATc. Strikingly, Western blotting and immunocytochemical experiments indicated that PDTC promoted a transient and rapid shuttling of NFATp and NFATc, leading to their accelerated export from the nucleus of activated T cells. We propose that the activation of an NFAT kinase by PDTC could be responsible for the rapid shuttling of the NFAT, therefore transiently converting the sustained transactivation of this transcription factor that occurs during lymphocyte activation, and show that c-Jun NH2-terminal kinase (JNK) can act by directly phosphorylating NFATp. In addition, the combined inhibitory effects on NFAT and NF-KB support a potential use of DTCs as immunosuppressants.

Martinez-Martinez, S; Gomez del Arco, P; Armesilla, A L; Aramburu, J; Luo, C; Rao, A; Redondo, J M

1997-01-01

100

HLA-G gene activation in tumor cells involves cis-acting epigenetic changes.  

PubMed

The tissue distribution of HLA-G molecules is broader than originally reported in trophoblastic cells. On the basis of numerous studies, HLA-G is also expressed in malignant tumors and involved in tumor immune escape. The mechanisms of HLA-G gene regulation differ from those of classical HLA class I genes and involve epigenetic processes. Here, we provide additional evidence on the influence of DNA demethylation on HLA-G activation. We also analyze the 5' regulatory region of HLA-G in 2 cellular models, melanoma (FON, M8) and choriocarcinoma (JEG-3, JAR), either expressing HLA-G transcripts or not. The data strongly suggest that HLA-G is silenced as a result of CpG site hypermethylation within a 5' regulatory region encompassing 450 bp upstream of the start codon, whereas it is activated upon demethylation. This result correlates with the acetylation status of histones within this region and the putative locus control region located at -1.2 kb. cis-acting epigenetic changes and the fact that demethylating agents activate HLA-G expression at least 5 days following treatment should be taken into account in epigenetic cancer therapies. PMID:15514928

Mouillot, Gaël; Marcou, Céline; Rousseau, Philippe; Rouas-Freiss, Nathalie; Carosella, Edgardo D; Moreau, Philippe

2005-03-01

101

Analyses of isoamylase gene activity in wild-type barley indicate its involvement in starch synthesis.  

PubMed

The notion of debranching enzyme activity as a participant in starch synthesis is gaining acceptance. Inconsistent reports from mutant analyses implicate either isoamylase or pullulanase as a determinant in amylopectin formation and whether wild-type plants utilize one or the other, or both, of these debranching enzymes in starch synthesis is unclear. Recent results on the sul mutant in maize suggest that both forms of debranching enzymes might be involved in amylopectin formation. We wished to find out if isoamylase takes part in starch synthesis by comparing isoamylase gene activity under three conditions: (1) during starch accumulation in developing sink tissues; (2) during starch degradation in germinating seeds; (3) in ectopic expression after applying sucrose, a starch precursor. We isolated the gene for barley isoamylase, isol, and analysed its expression and regulation in germinating seeds, developing endosperm and vegetative tissues, and compared the isoamylase gene expression in sink tissues from three different species. Our results indicate that isoamylase gene activity is involved in starch synthesis in wild-type plants and is modulated by sucrose. PMID:10437827

Sun, C; Sathish, P; Ahlandsberg, S; Jansson, C

1999-06-01

102

The benefits of in-group contact through physical activity involvement for health and well-being among Korean immigrants  

PubMed Central

This qualitative study is designed to examine the benefits of physical activity involvement with members of the same ethnic group. For this study, Korean immigrants who were members of Korean physical activity clubs such as badminton and tennis were selected as participants. Using a constructive grounded theory methodology, three themes were identified as benefits of physical activity involvement: (1) the experience of psychological well-being, (2) the creation of a unique cultural world, and (3) the facilitation of physical activity involvement. The findings of this study suggest that Korean immigrant participants gained various social, cultural, and psychological benefits by engaging in activities with other Korean immigrants.

Kim, Junhyoung; Heo, Jinmoo; Kim, Jun

2014-01-01

103

Rho-dependent kinase is involved in agonist-activated calcium entry in rat arteries.  

PubMed

The present study was aimed at investigating whether, besides its pivotal role in Ca(2+)-independent contraction of smooth muscle, Rho-kinase is involved in the mechanisms underlying the Ca2+ signal activated by noradrenaline in arteries. In rat aorta and mesenteric artery, the Rho-kinase inhibitor Y-27632 (10 microM) completely relaxed the contraction evoked by noradrenaline (1 microM) and simultaneously inhibited the Ca2+ signal by 54 +/- 1 % (mesenteric artery) and 71 +/- 15 % (aorta), and the cell membrane depolarisation by 56 +/- 11 % (mesenteric artery). A similar effect was observed in arteries contracted by AlF4-, while in KCl-contracted arteries, Y-27632 decreased tension without changing cytosolic Ca2+. The same effects were observed with another inhibitor of Rho-kinase (HA1077) but not with an inhibitor of protein kinase C (Ro-31-8220). Effects of Y-27632 were not prevented by incubating the artery in 25 mM KCl, with K+ channel blockers or with the Ca2+ channel blocker nimodipine. Y-27632 did not affect either the increase in the production of inositol phosphates activated by noradrenaline, or the release of Ca2+ from non-mitochondrial stores evoked by InsP3 in permeabilised aortic cells, or the Ca2+ signals evoked by thapsigargin or caffeine. The capacitative Ca2+ entry activated by thapsigargin was not impaired by Y-27632, but the entry of Ba2+ activated by noradrenaline in the presence of nimodipine was blocked by 10 microM Y-27632. These results indicate that Rho-kinase is involved in noradrenaline activation of a Ca2+ entry distinct from voltage- or store-operated channels in rat arteries. PMID:12853654

Ghisdal, Philippe; Vandenberg, Greet; Morel, Nicole

2003-09-15

104

Zebrafish reporter lines reveal in vivo signaling pathway activities involved in pancreatic cancer  

PubMed Central

Pancreatic adenocarcinoma, one of the worst malignancies of the exocrine pancreas, is a solid tumor with increasing incidence and mortality in industrialized countries. This condition is usually driven by oncogenic KRAS point mutations and evolves into a highly aggressive metastatic carcinoma due to secondary gene mutations and unbalanced expression of genes involved in the specific signaling pathways. To examine in vivo the effects of KRASG12D during pancreatic cancer progression and time correlation with cancer signaling pathway activities, we have generated a zebrafish model of pancreatic adenocarcinoma in which eGFP-KRASG12D expression was specifically driven to the pancreatic tissue by using the GAL4/UAS conditional expression system. Outcrossing the inducible oncogenic KRASG12D line with transgenic zebrafish reporters, harboring specific signaling responsive elements of transcriptional effectors, we were able to follow TGF?, Notch, Bmp and Shh activities during tumor development. Zebrafish transgenic lines expressing eGFP-KRASG12D showed normal exocrine pancreas development until 3 weeks post fertilization (wpf). From 4 to 24 wpf we observed several degrees of acinar lesions, characterized by an increase in mesenchymal cells and mixed acinar/ductal features, followed by progressive bowel and liver infiltrations and, finally, highly aggressive carcinoma. Moreover, live imaging analysis of the exocrine pancreatic tissue revealed an increasing number of KRAS-positive cells and progressive activation of TGF? and Notch pathways. Increase in TGF?, following KRASG12D activation, was confirmed in a concomitant model of medulloblastoma (MDB). Notch and Shh signaling activities during tumor onset were different between MDB and pancreatic adenocarcinoma, indicating a tissue-specific regulation of cell signaling pathways. Moreover, our results show that a living model of pancreatic adenocarcinoma joined with cell signaling reporters is a suitable tool for describing in vivo the signaling cascades and molecular mechanisms involved in tumor development and a potential platform to screen for novel oncostatic drugs.

Schiavone, Marco; Rampazzo, Elena; Casari, Alessandro; Battilana, Giusy; Persano, Luca; Moro, Enrico; Liu, Shu; Leach, Steve D.; Tiso, Natascia; Argenton, Francesco

2014-01-01

105

Involvement of TACE in colon inflammation: a novel mechanism of regulation via SIRT-1 activation.  

PubMed

TNF-? converting enzyme (TACE) processes the membrane TNF-? to release the bioactive soluble TNF-?. Several evidences suggest the involvement of TNF-? and TACE in inflammatory bowel disease (IBD). Tissue inhibitor of metalloproteinase (TIMP)-3, an endogenous inhibitor of TACE, is positively associated with silent information regulator (SIRT)-1. We aimed to study the expression of TACE, TIMP-3 and SIRT-1 at different stages of colitis and how TACE is regulated in response to SIRT-1 activation. Acute colitis was induced by 3.5% dextran sulfate sodium (DSS) in drinking water for 5days and levels of cytokines and mRNA expression of TACE, TIMP-3 and SIRT-1 were measured in colon at different time intervals. Next, the effect of SIRT-1 activator (resveratrol) or a selective TACE inhibitor (compound 11p) treatment was evaluated. Elevated levels of TNF-?, interleukin (IL)-6, IL-1?, interferon (IFN)-? and IL-17 were observed during DSS exposure phase which restored to the normal level after DSS removal. A significant increase in TACE and suppression in TIMP-3 and SIRT-1 mRNA level was observed during DSS exposure phase which reverts back to normal towards the remission phase. Treatment with resveratrol significantly elevated SIRT-1 and TIMP-3 and suppressed TACE mRNA expression and was associated with amelioration of disease. Furthermore, treatment with selective TACE inhibitor significantly suppressed body weight loss, disease activity index, colonic myeloperoxidase activity and the elevated levels of cytokines after DSS challenge. These results strongly emphasize the involvement of TACE in colon inflammation and inhibition of TACE directly or indirectly via SIRT-1 activation ameliorates colitis. PMID:24548422

Sharma, Manoranjan; Mohapatra, Jogeswar; Wagh, Akshaya; Patel, Hiren M; Pandey, Dheerendra; Kadam, Shekhar; Argade, Anil; Deshpande, Shrikalp S; Shah, Gourang B; Chatterjee, Abhijit; Jain, Mukul R

2014-03-01

106

Zebrafish reporter lines reveal in vivo signaling pathway activities involved in pancreatic cancer.  

PubMed

Pancreatic adenocarcinoma, one of the worst malignancies of the exocrine pancreas, is a solid tumor with increasing incidence and mortality in industrialized countries. This condition is usually driven by oncogenic KRAS point mutations and evolves into a highly aggressive metastatic carcinoma due to secondary gene mutations and unbalanced expression of genes involved in the specific signaling pathways. To examine in vivo the effects of KRAS(G12D) during pancreatic cancer progression and time correlation with cancer signaling pathway activities, we have generated a zebrafish model of pancreatic adenocarcinoma in which eGFP-KRAS(G12D) expression was specifically driven to the pancreatic tissue by using the GAL4/UAS conditional expression system. Outcrossing the inducible oncogenic KRAS(G12D) line with transgenic zebrafish reporters, harboring specific signaling responsive elements of transcriptional effectors, we were able to follow TGF?, Notch, Bmp and Shh activities during tumor development. Zebrafish transgenic lines expressing eGFP-KRAS(G12D) showed normal exocrine pancreas development until 3 weeks post fertilization (wpf). From 4 to 24 wpf we observed several degrees of acinar lesions, characterized by an increase in mesenchymal cells and mixed acinar/ductal features, followed by progressive bowel and liver infiltrations and, finally, highly aggressive carcinoma. Moreover, live imaging analysis of the exocrine pancreatic tissue revealed an increasing number of KRAS-positive cells and progressive activation of TGF? and Notch pathways. Increase in TGF?, following KRAS(G12D) activation, was confirmed in a concomitant model of medulloblastoma (MDB). Notch and Shh signaling activities during tumor onset were different between MDB and pancreatic adenocarcinoma, indicating a tissue-specific regulation of cell signaling pathways. Moreover, our results show that a living model of pancreatic adenocarcinoma joined with cell signaling reporters is a suitable tool for describing in vivo the signaling cascades and molecular mechanisms involved in tumor development and a potential platform to screen for novel oncostatic drugs. PMID:24878567

Schiavone, Marco; Rampazzo, Elena; Casari, Alessandro; Battilana, Giusy; Persano, Luca; Moro, Enrico; Liu, Shu; Leach, Steve D; Tiso, Natascia; Argenton, Francesco

2014-07-01

107

Ovulation involves the luteinizing hormone-dependent activation of G(q/11) in granulosa cells.  

PubMed

The LH receptor (LHR) activates several families of heterotrimeric G proteins, but only the activation of Gs and subsequent generation of cAMP are universally accepted as important mediators of LH actions. To examine the involvement of the Gq/11 family on the actions of LH, we crossed Cyp19Cre and G?q(f/f);G?11(-/-) mice to generate mice with a granulosa cell-specific deletion of G?q in the context of a global deletion of G?11. Granulosa cells from G?q(f/f);G?11(-/-);Cre(+) mice have barely detectable levels of G?q/11, have a normal complement of LHR, and respond to LHR activation with a transient increase in cAMP accumulation, but they fail to respond with increased inositol phosphate accumulation, an index of the activation of G?q/11. The LHR-provoked resumption of meiosis, cumulus expansion, and luteinization are normal. However, the G?q(f/f);G?11(-/-);Cre(+) mice display severe subfertility because many of the oocytes destined for ovulation become entrapped in preovulatory follicles or corpora lutea. Because follicular rupture is known to be dependent on the expression of the progesterone receptor (Pgr), we examined the LHR-induced expression of Pgr and 4 of its target genes (Adamts-1, Ctsl1, Edn2, and Prkg2). These actions of the LHR were impaired in the ovaries of the G?q(f/f);G?11(-/-);Cre(+) mice. We conclude that the defect in follicular rupture is secondary to the failure of the LHR to fully induce the expression of the Pgr. This is the first conclusive evidence for the physiological importance of the activation of Gq/11 by the LHR and for the involvement of G?q/11 in ovulation. PMID:23836924

Breen, Shawn M; Andric, Nebojsa; Ping, Tai; Xie, Fang; Offermans, Stefan; Gossen, Jan A; Ascoli, Mario

2013-09-01

108

Involvement of multiple elements in FXR-mediated transcriptional activation of FGF19.  

PubMed

The intestinal endocrine hormone human fibroblast growth factor 19 (FGF19) is involved in the regulation of not only hepatic bile acid metabolism but also carbohydrate and lipid metabolism. In the present study, bile acid/farnesoid X receptor (FXR) responsiveness in the FGF19 promoter region was investigated by a reporter assay using the human colon carcinoma cell line LS174T. The assay revealed the presence of bile acid/FXR-responsive elements in the 5'-flanking region up to 8.8 kb of FGF19. Deletion analysis indicated that regions from -1866 to -1833, from -1427 to -1353, and from -75 to +262 were involved in FXR responsiveness. Four, four, and two consecutive half-sites of nuclear receptors were observed in the three regions, respectively. An electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay revealed FXR/retinoid X receptor ? (RXR?) heterodimer binding in these three regions. EMSA and reporter assays using mutated constructs indicated that the nuclear receptor IR1, ER2, and DR8 motifs in the 5'-flanking region were involved in FXR responsiveness of FGF19. Lithocholic acid (LCA) (10 ?M), chenodeoxycholic acid (CDCA) (10 ?M), or GW4064 (0.1 ?M) treatment increased reporter activity in a construct including the three motifs under FXR-expressing conditions whereas LCA and not CDCA or GW4064 treatment increased the reporter activity under pregnane X receptor (PXR)-expressing conditions. These results suggest that FGF19 is transcriptionally activated through multiple FXR-responsive elements in the promoter region. PMID:22561792

Miyata, Masaaki; Hata, Tatsuya; Yamakawa, Hiroki; Kagawa, Tatehiro; Yoshinari, Kouichi; Yamazoe, Yasushi

2012-10-01

109

Perceived community environment and physical activity involvement in a northern-rural Aboriginal community  

PubMed Central

Background Type 2 diabetes disproportionately affects Aboriginal peoples in Canada. Ample evidence shows that regular physical activity (PA) plays an important role in the prevention and treatment of type 2 diabetes. Evidence is beginning to emerge linking PA to the physical environment but little is known about the relationship between remote rural environments and PA involvement in Aboriginal peoples. This study's purpose was to investigate the relationship between perceptions of the environment and PA and walking patterns in Aboriginal adults in order to inform the planning and implementation of community-relevant PA interventions. Methods Two hundred and sixty three residents (133 women, mean age = 35.6 years, SD = 12.3 and 130 men, mean age = 37.2 years, SD = 13.1) from Moose Factory, Ontario were asked about environmental factors related to walking and PA involvement. Survey items were drawn from standardized, validated questionnaires. Descriptive statistics (means, standard deviations, percentages) were calculated. A series of hierarchical multiple regressions were performed to determine associations between walking and overall PA with perceived environmental variables. Results Hierarchical multiple regression to predict walking revealed significant associations between walking and perceived safety and aesthetics. Owning home exercise equipment predicted strenuous PA. Different aspects of the physical environment appear to influence different types of physical activities. The significant amount of variance in behaviour accounted for by perceived environmental variables (5.3% walking) included safety, aesthetics, convenience, owning home exercise equipment and comfortable shoes for walking. Conclusion Results suggest that a supportive physical environment is important for PA involvement and that walking and activities of different intensity appear to be mediated by different perceived environmental variables. Implications for PA promotion in rural environments where Aboriginal people face many unique environmental features (e.g., bears, mosquitoes, extreme cold) are discussed.

Kirby, Allison M; Levesque, Lucie; Wabano, Virgina; Robertson-Wilson, Jennifer

2007-01-01

110

Involvement of microglia activation in the lead induced long-term potentiation impairment.  

PubMed

Exposure of Lead (Pb), a known neurotoxicant, can impair spatial learning and memory probably via impairing the hippocampal long-term potentiation (LTP) as well as hippocampal neuronal injury. Activation of hippocampal microglia also impairs spatial learning and memory. Thus, we raised the hypothesis that activation of microglia is involved in the Pb exposure induced hippocampal LTP impairment and neuronal injury. To test this hypothesis and clarify its underlying mechanisms, we investigated the Pb-exposure on the microglia activation, cytokine release, hippocampal LTP level as well as neuronal injury in in vivo or in vitro model. The changes of these parameters were also observed after pretreatment with minocycline, a microglia activation inhibitor. Long-term low dose Pb exposure (100 ppm for 8 weeks) caused significant reduction of LTP in acute slice preparations, meanwhile, such treatment also significantly increased hippocampal microglia activation as well as neuronal injury. In vitro Pb-exposure also induced significantly increase of microglia activation, up-regulate the release of cytokines including tumor necrosis factor-alpha (TNF-?), interleukin-1? (IL-1?) and inducible nitric oxide synthase (iNOS) in microglia culture alone as well as neuronal injury in the co-culture with hippocampal neurons. Inhibiting the microglia activation with minocycline significantly reversed the above-mentioned Pb-exposure induced changes. Our results showed that Pb can cause microglia activation, which can up-regulate the level of IL-1?, TNF-? and iNOS, these proinflammatory factors may cause hippocampal neuronal injury as well as LTP deficits. PMID:22952811

Liu, Ming-Chao; Liu, Xin-Qin; Wang, Wen; Shen, Xue-Feng; Che, Hong-Lei; Guo, Yan-Yan; Zhao, Ming-Gao; Chen, Jing-Yuan; Luo, Wen-Jing

2012-01-01

111

VASP is involved in cAMP-mediated Rac 1 activation in microvascular endothelial cells.  

PubMed

Accumulating evidence points to a significant role of vasodilator-stimulated phosphoprotein (VASP) in the maintenance of endothelial barrier functions. We have recently shown that impaired barrier functions in VASP-deficient microvascular myocardial endothelial cells (MyEnd VASP(-/-)) correlated with decreased Rac 1 activity. To further test the hypothesis that VASP is involved in regulation of Rac 1 activity, we studied cAMP-dependent Rac 1 activation. Both inhibition of Rac 1 activation by NSC-23766 and inhibition of PKA by PKI completely blunted the efficacy of forskolin/rolipram (F/R)-mediated cAMP increase to stabilize barrier functions as revealed by measurements of transendothelial resistance (TER). Because these results indicate that PKA/Rac 1 activation is important for barrier stabilization, we tested this signaling pathway in VASP(-/-) cells. We found that F/R and isoproterenol reduced permeability measured as FITC-dextran flux across VASP(-/-) monolayers, but not below baseline levels of wild-type cells (WT). Moreover, cAMP-mediated Rac 1 activation was reduced to approximately 50% of WT levels, and both PKA inhibition by PKI and PKA anchoring via A kinase anchoring peptides (AKAPs) by HT31 almost completely abolished Rac 1 activation in VASP(-/-) and WT endothelium. Accordingly, HT31 significantly reduced F/R-mediated TER increase in WT cells and completely blocked the protective effect of cAMP on endothelial barrier properties. Together, our data underline the significant role of cAMP-mediated Rac 1 activation for endothelial barrier stabilization and demonstrate that both AKAP-mediated PKA anchoring and VASP are required for this process. PMID:19118163

Schlegel, Nicolas; Waschke, Jens

2009-03-01

112

Involvement of Autonomic Nervous Activity Changes in Gastroesophageal Reflux in Neonates during Sleep and Wakefulness  

PubMed Central

Background It has been suggested that disturbed activity of the autonomic nervous system is one of the factors involved in gastroesophageal reflux (GER) in adults. We sought to establish whether transient ANS dysfunction (as assessed by heart rate variability) is associated with the occurrence of GER events in neonates during sleep and wakefulness. Methods Nineteen neonates with suspected GER underwent simultaneous, synchronized 12-hour polysomnography and esophageal multichannel impedance-pH monitoring. We compared changes in HRV parameters during three types of periods (control and prior to and during reflux) with respect to the vigilance state. Results The vigilance state influenced the distribution of GER events (P<0.001), with 53.4% observed during wakefulness, 37.6% observed during active sleep and only 9% observed during quiet sleep. A significant increase in the sympathovagal ratio (+32%, P=0.013) was observed in the period immediately prior to reflux (due to a 15% reduction in parasympathetic activity (P=0.017)), relative to the control period. This phenomenon was observed during both wakefulness and active sleep. Conclusion Our results showed that GER events were preceded by a vigilance-state-independent decrease in parasympathetic tone. This suggests that a pre-reflux change in ANS activity is one of the factors contributing to the mechanism of reflux in neonates.

Djeddi, Djamal-Dine; Kongolo, Guy; Stephan-Blanchard, Erwan; Ammari, Mohamed; Leke, Andre; Delanaud, Stephane; Bach, Veronique; Telliez, Frederic

2013-01-01

113

Inhibition of Fast Axonal Transport by Pathogenic SOD1 Involves Activation of p38 MAP Kinase  

PubMed Central

Dying-back degeneration of motor neuron axons represents an established feature of familial amyotrophic lateral sclerosis (FALS) associated with superoxide dismutase 1 (SOD1) mutations, but axon-autonomous effects of pathogenic SOD1 remained undefined. Characteristics of motor neurons affected in FALS include abnormal kinase activation, aberrant neurofilament phosphorylation, and fast axonal transport (FAT) deficits, but functional relationships among these pathogenic events were unclear. Experiments in isolated squid axoplasm reveal that FALS-related SOD1 mutant polypeptides inhibit FAT through a mechanism involving a p38 mitogen activated protein kinase pathway. Mutant SOD1 activated neuronal p38 in mouse spinal cord, neuroblastoma cells and squid axoplasm. Active p38 MAP kinase phosphorylated kinesin-1, and this phosphorylation event inhibited kinesin-1. Finally, vesicle motility assays revealed previously unrecognized, isoform-specific effects of p38 on FAT. Axon-autonomous activation of the p38 pathway represents a novel gain of toxic function for FALS-linked SOD1 proteins consistent with the dying-back pattern of neurodegeneration characteristic of ALS.

Morfini, Gerardo A.; Bosco, Daryl A.; Brown, Hannah; Gatto, Rodolfo; Kaminska, Agnieszka; Song, Yuyu; Molla, Linda; Baker, Lisa; Marangoni, M. Natalia; Berth, Sarah; Tavassoli, Ehsan; Bagnato, Carolina; Tiwari, Ashutosh; Hayward, Lawrence J.; Pigino, Gustavo F.; Watterson, D. Martin; Huang, Chun-Fang; Banker, Gary; Brown, Robert H.; Brady, Scott T.

2013-01-01

114

22 CFR 40.25 - Certain aliens involved in serious criminal activity who have asserted immunity from prosecution...  

Code of Federal Regulations, 2013 CFR

...Relations 1 2013-04-01 2013-04-01 false Certain aliens involved in serious criminal activity who have asserted immunity...Grounds-Conviction of Certain Crimes § 40.25 Certain aliens involved in serious criminal activity who have asserted...

2013-04-01

115

Direct involvement of the TEN domain at the active site of human telomerase  

PubMed Central

Telomerase is a ribonucleoprotein that adds DNA to the ends of chromosomes. The catalytic protein subunit of telomerase (TERT) contains an N-terminal domain (TEN) that is important for activity and processivity. Here we describe a mutation in the TEN domain of human TERT that results in a greatly increased primer Kd, supporting a role for the TEN domain in DNA affinity. Measurement of enzyme kinetic parameters has revealed that this mutant enzyme is also defective in dNTP polymerization, particularly while copying position 51 of the RNA template. The catalytic defect is independent of the presence of binding interactions at the 5?-region of the DNA primer, and is not a defect in translocation rate. These data suggest that the TEN domain is involved in conformational changes required to position the 3?-end of the primer in the active site during nucleotide addition, a function which is distinct from the role of the TEN domain in providing DNA binding affinity.

Jurczyluk, Julie; Nouwens, Amanda S.; Holien, Jessica K.; Adams, Timothy E.; Lovrecz, George O.; Parker, Michael W.; Cohen, Scott B.; Bryan, Tracy M.

2011-01-01

116

Involvement of glucocorticoid receptor activation on anti-inflammatory effect induced by peroxisome proliferator-activated receptor ? agonist in mice.  

PubMed

Glucocorticoids are effective anti-inflammatory agents widely used for the treatment of acute and chronic inflammatory diseases. Recent in vitro studies have proposed that glucocorticoid receptor (GR) activation is involved in peroxisome proliferator-activated receptor ? (PPAR?) agonist-induced effects. In this study, to examine the involvement of the GR in PPAR? agonist- and retinoid X receptor (RXR) agonist-mediated anti-inflammatory effects in vivo, we tested the anti-inflammatory effects of dexamethasone (a GR agonist) with pioglitazone (a PPAR? agonist) or 6-[N-ethyl-N-(3-isopropoxy-4-isopropylphenyl)-amino] nicotinic acid (NEt-3IP; an RXR agonist) by using an experimental model of carrageenan-induced inflammation. We also evaluated the effects of a GR antagonist on PPAR? agonist- or RXR agonist-induced anti-inflammatory effects. Results showed that the GR antagonist RU486 reduced the anti-inflammatory effects of GR or PPAR? agonists but not those of the RXR agonist. In addition, combinations of GR and PPAR? agonists or GR and RXR agonists had no effect on carrageenan-induced paw edema. Moreover, the PPAR? antagonist GW9662 and RXR antagonist 6-[N-4-(trifluoromethyl)-benzenesulfonyl-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)-amino] nicotinic acid (NS-4TF) had no effect on the anti-inflammatory effect of the GR agonist dexamethasone. Therefore, it is suggested that GR activation in vivo does not play a direct role in PPAR?/RXR heterodimer signaling. In contrast, pioglitazone showed a partial anti-inflammatory effect via GR activation. These data provide evidence for the pro-inflammatory activity of pioglitazone. PMID:24975659

Yamamoto, Atsuki; Kakuta, Hiroki; Sugimoto, Yukio

2014-09-01

117

Trabecular bone remodelling under pathological conditions based on biochemical and mechanical processes involved in BMU activity.  

PubMed

In adulthood, bone tissue is continuously renewed by processes governed by basic multicellular units composed of osteocytes, osteoclasts and osteoblasts, which are subjected to local mechanical loads. Osteocytes are known to be integrated mechanosensors that regulate the activation of the osteoclasts and osteoblasts involved in bone resorption and apposition processes, respectively. After collagen tissue apposition, a process of collagen mineralisation takes place, gradually increasing the effective stiffness of bone. This study presents a new model based on physicochemical parameters involved in spongy bone remodelling under pathological conditions. Our model simulates the transient evolution of both geometry and effective Young's modulus of the trabeculae, also taking turnover into account. Various loads were applied on a trabecula in order to determine the evolution of bone volume fraction under pathological conditions. A parametric study performed on the model showed that one key parameter here is the kinetic constant of hydroxyapatite crystallisation. We subsequently tested our model on a pathological case approaching osteoporosis, involving a decrease in the number of viable osteocytes present in bone. The model converges to a lower value (- 5%) for bone volume fraction than with a normal quantity of osteocytes. This useful tool offers new perspectives for predicting bone remodelling deficits on a local scale in patients with pathological conditions such as osteoporosis and in bedridden patients, as well as for astronauts subjected to weightlessness in space. PMID:22289038

Liotier, P J; Rossi, J M; Wendling-Mansuy, S; Chabrand, P

2013-01-01

118

RP105 involved in activation of mouse macrophages via TLR2 and TLR4 signaling.  

PubMed

RP105 is a member of the toll-like receptor family of proteins that transmits an activation signal in B cells, playing a role in regulation of B cell growth and death; in macrophages and dendritic cells, RP105 is a specific inhibitor of TLR4 signaling. RP105 is uniquely important for regulating TLR4-dependent signaling. It also proved that RP105 is closely related to TLR2 in macrophage activation by Mycobacterium tuberculosis lipoproteins. The aim of our study is to investigate the role of RP105 in mouse macrophages activation of TLR4 and TLR2 signaling by lipopolysaccharides (LPS) and Pam3CysSerLys4 (Pam3CSK4) alone or in combination, and the interaction between TLR2 and TLR4 signaling through RP105. Our results indicate that besides exhibiting negative regulation of TNF-? and IL12-p40 secretion in macrophage activated by LPS, RP105 is also involved in macrophages activation by Pam3CSK4 through TLR2 signaling and exhibited regulation to IL-10 and RANTES production by mouse peritoneal macrophage activated by Pam3CSK4. In macrophages activation by LPS and Pam3CSK4 in combination, TLR2 signaling can overcome RP105-mediated regulation of TLR4 signaling. Thus, our data demonstrate that not only TLR4 signaling, but also RP105 appears to be an essential accessory for immune responses through TLR2 signaling. The function of TLR2 and TLR4 in response to TLR ligands could be associated with each other by RP105. These results can help us understanding the unique role of RP105 in macrophages response to TLR ligands. PMID:23483427

Liu, Bo; Zhang, Naisheng; Liu, Zhicheng; Fu, Yunhe; Feng, Shuang; Wang, Shan; Cao, Yongguo; Li, Depeng; Liang, Dejie; Li, Fengyang; Song, Xiaojing; Yang, Zhengtao

2013-06-01

119

Pitx factors are involved in basal and hormone-regulated activity of the human prolactin promoter.  

PubMed

The pituitary-specific POU homeodomain factor Pit-1 likely interacts with other factors for cell-specific expression of prolactin. Here we identify the paired-like homeobox transcription factors Pitx1 and Pitx2 as factors functionally activating the proximal human prolactin promoter (hPRL-164luc). Using in vitro binding assays and a series of site-specific mutations of the proximal hPRL promoter, we mapped the B1 and B2 bicoid sites involved in Pitx-mediated transactivation of the hPRL-164luc construct. In somatolactotroph GH4C1 cells, basal proximal hPRL promoter activity was inhibited by a Pitx2 dominant-negative form in a dose-dependent manner, whereas binding disruptive mutations in the Pitx sites significantly reduced basal activity of the promoter. We also show that synergistic activation of hPRL-164luc by Pitx2 and Pit-1 requires the integrity of the B2 Pitx binding site, and at least one of the P1 and P2 Pit-1 response elements. In addition, mutation in the B2 Pitx site results in attenuation of the promoter's responsiveness to forskolin, thyrotropin-releasing hormone, and epidermal growth factor. Conversely, Pitx1 or Pitx2 overexpression in GH4C1 cells leads to an enhancement of the drugs stimulatory effects. Altogether, these results suggest that full responsiveness to several signaling pathways regulating the hPRL promoter requires the B2 Pitx binding site and that Pitx factors may be part of the proteic complex involved in these regulations. Finally, in situ hybridization analysis showing coexpression of the PRL and Pitx2 genes in rat and human lactotroph cells corroborates the physiological relevance of these results. PMID:12223489

Quentien, Marie-Hélène; Manfroid, Isabelle; Moncet, Daniel; Gunz, Ginette; Muller, Marc; Grino, Michel; Enjalbert, Alain; Pellegrini, Isabelle

2002-11-15

120

NRF2 activation is involved in ozonated human serum upregulation of HO-1 in endothelial cells.  

PubMed

During the last decade, it has been shown that the activation of NRF2 and the binding to electrophile-responsive element (EpREs), stimulates the expression of a great number of genes responsible for the synthesis of phase I and phase II proteins, including antioxidants enzymes and heme oxygenase-1 (HO-1). This critical cell response occurs in cardiovascular, degenerative and chronic infective diseases aggravated by a chronic oxidative stress. In our previous reports we have shown that ozonated plasma is able to up-regulate HO-1 expression in endothelial cells. In the present work we investigated a candidate mechanism involved in this process. After treatment with increasing doses of ozonated serum (20, 40 and 80 ?g/mL O(3) per mL of serum), a clear dose dependent activation of NRF2 and the subsequent induction of HO-1 and NAD(P)H quinone oxidoreductase 1(NQO1) was observed. This effect was also present when cells were treated with serum and hydrogen peroxide (H(2)O(2)) or serum and 4-hydroxynonenal (4HNE). Moreover, the treatment with ozonated serum was associated with a dose-dependent activation of extracellular-signal-regulated kinases (ERK1/2) and p38 MAP kinases (p38), not directly involved in NRF2 activation. These data, provide a new insight on the mechanism responsible for the induction of HO-1 expression by ozonated serum in the endothelium, and have a practical importance as an expedient approach to the treatment of patients with both effective orthodox drugs and ozonated autohemotherapy, targeted to the restoration of redox homeostasis. PMID:23253326

Pecorelli, Alessandra; Bocci, Velio; Acquaviva, Alessandra; Belmonte, Giuseppe; Gardi, Concetta; Virgili, Fabio; Ciccoli, Lucia; Valacchi, Giuseppe

2013-02-15

121

Transcriptional activation by TLX1/HOX11 involves Gro/TLE corepressors  

PubMed Central

The role of Groucho/transducin-like Enhancer of split (Gro/TLE) family members as corepressors of transcription is well documented. TLX1 is a homeodomain transcription factor involved in splenogenesis and neuron formation, and its aberrant expression gives rise to T-cell acute lymphoblastic leukemia. We demonstrate by glutathione-S-transferase pull-down assays, in vivo biotinylation tagging and confocal laser microscopy that TLX1 interacts with TLE1 via an Eh1-like motif. Paradoxically, we found that this motif is essential for optimal transcriptional activation of two TLX1 target genes, Aldh1a1 and Fhl1. Using a well characterized target of the Hairy/Enhancer of split 1 (HES1)·TLE1 repressor complex, the ASCL1 gene, we show that TLX1 counteraction of ASCL1 repression by HES1 in SK-N-BE(2) neuroblastoma cells is associated with dismissal of TLE1 from the ASCL1 promoter and requires the Eh1-like motif for maximal effect. Collectively, these results indicate that TLX1-mediated target gene activation can occur in part via derepression strategies involving Gro/TLE corepressors.

Riz, Irene; Lee, Hyo Jung; Baxter, Kristin K.; Behnam, Reza; Hawley, Teresa S.; Hawley, Robert G.

2009-01-01

122

Internalization of Clostridium perfringens ?-toxin leads to ERK activation and is involved on its cytotoxic effect.  

PubMed

Clostridium perfringens phospholipase C (CpPLC), also called ?-toxin, plays a key role in the pathogenesis of gas gangrene. CpPLC may lead to cell lysis at concentrations that cause extensive degradation of plasma membrane phospholipids. However, at sublytic concentrations it induces cytotoxicity without inducing evident membrane damage. The results of this work demonstrate that CpPLC becomes internalized in cells by a dynamin-dependent mechanism and in a time progressive process: first, CpPLC colocalizes with caveolin both at the plasma membrane and in vesicles, and later it colocalizes with early and late endosomes and lysosomes. Lysosomal damage in the target cells is evident 9?h after CpPLC exposure. Our previous work demonstrated that CpPLCinduces ERK1/2 activation, which is involved in its cytotoxic effect. In this work we found that cholesterol sequestration, dynamin inhibition, as well as inhibition of actin polymerization, prevent CpPLC internalization and ERK1/2 activation, involving endocytosis in the signalling events required for CpPLC cytotoxic effect at sublytic concentrations. These results provide new insights about the mode of action of this bacterial phospholipase C, previously considered to act only locally on cell membrane. PMID:24245664

Monturiol-Gross, Laura; Flores-Díaz, Marietta; Campos-Rodríguez, Diana; Mora, Rodrigo; Rodríguez-Vega, Mariela; Marks, David L; Alape-Girón, Alberto

2014-04-01

123

Involvement of a phospholipase C in the hemolytic activity of a clinical strain of Pseudomonas fluorescens  

PubMed Central

Background Pseudomonas fluorescens is a ubiquitous Gram-negative bacterium frequently encountered in hospitals as a contaminant of injectable material and surfaces. This psychrotrophic bacterium, commonly described as unable to grow at temperatures above 32°C, is now considered non pathogenic. We studied a recently identified clinical strain of P. fluorescens biovar I, MFN1032, which is considered to cause human lung infection and can grow at 37°C in laboratory conditions. Results We found that MFN1032 secreted extracellular factors with a lytic potential at least as high as that of MF37, a psychrotrophic strain of P. fluorescens or the mesophilic opportunistic pathogen, Pseudomonas aeruginosa PAO1. We demonstrated the direct, and indirect – through increases in biosurfactant release – involvement of a phospholipase C in the hemolytic activity of this bacterium. Sequence analysis assigned this phospholipase C to a new group of phospholipases C different from those produced by P. aeruginosa. We show that changes in PlcC production have pleiotropic effects and that plcC overexpression and plcC extinction increase MFN1032 toxicity and colonization, respectively. Conclusion This study provides the first demonstration that a PLC is involved in the secreted hemolytic activity of a clinical strain of Pseudomonas fluorescens. Moreover, this phospholipase C seems to belong to a complex biological network associated with the biosurfactant production.

Rossignol, Gaelle; Merieau, Annabelle; Guerillon, Josette; Veron, Wilfried; Lesouhaitier, Olivier; Feuilloley, Marc GJ; Orange, Nicole

2008-01-01

124

Study of possible mechanisms involved in the inhibitory effects of coumarin derivatives on neutrophil activity.  

PubMed

To specify the site of action of the synthetic coumarin derivatives 7-hydroxy-3-(4'-hydroxyphenyl) coumarin (HHC) and 7-hydroxy-3-(4'-hydroxyphenyl) dihydrocoumarin (HHDC), we evaluated their effects on extra- and intracellular reactive oxygen species (ROS) formation in phorbol-myristate-13-acetate (PMA) stimulated human neutrophils. We studied also the effects of HHC and HHDC on possible molecular mechanisms which participate in the activation of NADPH oxidase, that is, on PKC activity, on phosphorylation of some PKC isoforms (?, ?II, and ?), and on phosphorylation of the NADPH oxidase subunit p40(phox). Without affecting cytotoxicity, both coumarines tested were effective inhibitors/scavengers of ROS produced by neutrophils on extracellular level. HHC markedly diminished oxidant production and also, intracellularly, decreased PKC activity and partly phosphorylation of PKC?, ?II. On the other hand, we did not observe any effect of coumarin derivatives on phosphorylation of PKC ? and on phosphorylation of the NADPH oxidase subunit p40(phox), which were suggested to be involved in the PMA-dependent intracellular activation process. In agreement with our previous findings, we assume that the different molecular structures of HHC and HHDC with their different physicochemical and free radical scavenging characteristics are responsible for their diverse effects on the parameters tested. PMID:24349608

Drábiková, Katarína; Pere?ko, Tomáš; Nosál', Radomír; Harmatha, Juraj; Smidrkal, Jan; Jan?inová, Viera

2013-01-01

125

Study of Possible Mechanisms Involved in the Inhibitory Effects of Coumarin Derivatives on Neutrophil Activity  

PubMed Central

To specify the site of action of the synthetic coumarin derivatives 7-hydroxy-3-(4?-hydroxyphenyl) coumarin (HHC) and 7-hydroxy-3-(4?-hydroxyphenyl) dihydrocoumarin (HHDC), we evaluated their effects on extra- and intracellular reactive oxygen species (ROS) formation in phorbol-myristate-13-acetate (PMA) stimulated human neutrophils. We studied also the effects of HHC and HHDC on possible molecular mechanisms which participate in the activation of NADPH oxidase, that is, on PKC activity, on phosphorylation of some PKC isoforms (?, ?II, and ?), and on phosphorylation of the NADPH oxidase subunit p40phox. Without affecting cytotoxicity, both coumarines tested were effective inhibitors/scavengers of ROS produced by neutrophils on extracellular level. HHC markedly diminished oxidant production and also, intracellularly, decreased PKC activity and partly phosphorylation of PKC?, ?II. On the other hand, we did not observe any effect of coumarin derivatives on phosphorylation of PKC? and on phosphorylation of the NADPH oxidase subunit p40phox, which were suggested to be involved in the PMA-dependent intracellular activation process. In agreement with our previous findings, we assume that the different molecular structures of HHC and HHDC with their different physicochemical and free radical scavenging characteristics are responsible for their diverse effects on the parameters tested.

Drabikova, Katarina; Perecko, Tomas; Nosal', Radomir; Harmatha, Juraj; Smidrkal, Jan; Jancinova, Viera

2013-01-01

126

Involvement of caspase 3-activated DNase in internucleosomal DNA cleavage induced by diverse apoptotic stimuli.  

PubMed

Degradation of chromosomal DNA into nucleosome-sized fragments is one of the characteristics of apoptotic cell death. Here, we examined whether caspase-activated DNase (CAD) is responsible for the DNA fragmentation that occurs upon exposure to various apoptotic stimuli. When human Jurkat cells were exposed to etoposide, or UV or gamma radiation, a caspase-3-like protease was activated, and nuclear DNA was fragmented. Human TF-1 cells, which are dependent on granulocyte-macrophage colony-stimulating factor (GM-CSF), also underwent apoptosis accompanied by the activation of caspase-3-like protease and DNA fragmentation, when cultured without the cytokine. Both Jurkat and TF-1 cells expressed two forms of ICAD, ICAD-L and ICAD-S, which were cleaved upon exposure to these apoptotic stimuli. Among eight different caspases examined, recombinant caspases 3 and 7 specifically cleaved ICAD synthesized in a cell-free system. An expression plasmid containing mouse ICAD-L mutated at the caspase-3-recognition sites was then introduced into Jurkat and TF-1 cells. When the transformants were induced to undergo apoptosis (by treatment with etoposide, UV or gamma radiation for Jurkat cells, or factor withdrawal for TF-1 cells) they did not show DNA fragmentation, although they still died as a result of these stimuli. These results indicated that CAD, released from ICAD by caspase activation, is involved in the nuclear DNA fragmentation induced by these apoptotic stimuli. PMID:10442630

McIlroy, D; Sakahira, H; Talanian, R V; Nagata, S

1999-08-01

127

A novel enzyme activity involving the demethylation of specific partially methylated oligogalacturonides.  

PubMed Central

Studies of the enzymic digestion of pectic substrates using different polygalacturonase (PG) preparations have revealed evidence for a previously unreported enzyme activity carried out by a contaminating enzyme in one of the preparations. This observed activity involves the demethylation of specific oligogalacturonides, namely 2-methyltrigalacturonic acid and 2,3-dimethyltetragalacturonic acid. However, no large-scale demethylation of highly methylated polymeric substrates is found, demonstrating that the enzyme responsible is not a conventional pectin methylesterase (PME). Furthermore, it has been shown that a commercial sample of fungal PME from Aspergillus niger demethylates all of the oligogalacturonides present as primary products of endo-PG digestion, in contrast with the activity observed here. On the basis of the known methyl ester distribution of the endo-PG-generated fragments and knowledge of which of these oligogalacturonides are demethylated, it is concluded that the observed activity can be explained by the existence of an exo-acting methylesterase that attacks the non-reducing end of the oligogalacturonide molecules.

Williams, Martin A K; Benen, Jacques A E

2002-01-01

128

Transformation of immortalized colorectal crypt cells by microcystin involving constitutive activation of Akt and MAPK cascade.  

PubMed

It has been shown by epidemiological and animal studies that microcystin is an important exogenous factor involved in the carcinogenesis of colorectal cancer (CRC). However, details of the mechanism remain unclear. Transformation of colorectal cells is an important initial step in carcinogenesis. Whether microcystin is capable of transforming immortalized colorectal crypt cells, and what the mechanism might be, was investigated. In the present study, we demonstrated that immortalized colorectal crypt cells could be transformed by microcystin. Transformed colorectal crypt cells showed an anchorage-independent growth phenotype, and the proliferation activities of microcystin-transformed cells were also greater than that of immortalized colorectal crypt cells. The Akt and the p38, JNK of mitogen-activated protein kinase (MAPK) pathways in microcystin-transformed cells were found to be constitutively activated. In microcystin-transformed cells, PI3K, MAPKAPK2, Akt, cyclin D1 and cyclin D3 in the Akt pathway; IQGAP-2, RabGTPase, Rap1GAP, RasGAP, R-Ras, Krev-1 and TC21 of the Ras GTP/GDP protein family; and A-Raf, B-Raf and PAK in the Ras/MAPK pathway were all markedly upregulated. However, in positive control cells, dimethylhydrazine-transformed cells, only the Akt pathway was activated by PI3K, and no evidence of alteration of any molecules of the Ras superfamily was observed. Inhibition of Akt, p38 and JNK activation led to a reduced proliferation of microcystin-transformed cells. This implies that the constitutive activation of Akt and the p38, JNK of MAPK pathways in microcystin-transformed cells may be the mechanism by which this important external factor acts in the carcinogenesis of CRC. PMID:15774489

Zhu, Yongliang; Zhong, Xian; Zheng, Shu; Ge, Zhen; Du, Qin; Zhang, Suzhang

2005-07-01

129

Vimentin Is Involved in Peptidylarginine Deiminase 2-Induced Apoptosis of Activated Jurkat Cells  

PubMed Central

Peptidylarginine deiminase type 2 (PADI2) deiminates (or citrullinates) arginine residues in protein to citrulline residues in a Ca2+-dependent manner, and is found in lymphocytes and macrophages. Vimentin is an intermediate filament protein and a well-known substrate of PADI2. Citrullinated vimentin is found in ionomycin-induced macrophage apoptosis. Citrullinated vimentin is the target of anti-Sa antibodies, which are specific to rheumatoid arthritis, and play a critical role in the pathogenesis of the disease. To investigate the role of PADI2 in apoptosis, we generated a Jurkat cell line that overexpressed the PADI2 transgene from a tetracycline-inducible promoter, and used a combination of 12-O-tetradecanoylphorbol-13-acetate and ionomycin to activate Jurkat cells. We found that PADI2 overexpression reduced the cell viability of activated Jurkat cells in a dose- and time-dependent manner. The PADI2-overexpressed and -activated Jurkat cells presented typical manifestations of apoptosis, and exhibited greater levels of citrullinated proteins, including citrullinated vimentin. Vimentin overexpression rescued a portion of the cells from apoptosis. In conclusion, PADI2 overexpression induces apoptosis in activated Jurkat cells. Vimentin is involved in PADI2-induced apoptosis. Moreover, PADI2-overexpressed Jurkat cells secreted greater levels of vimentin after activation, and expressed more vimentin on their cell surfaces when undergoing apoptosis. Through artificially highlighting PADI2 and vimentin, we demonstrated that PADI2 and vimentin participate in the apoptotic mechanisms of activated T lymphocytes. The secretion and surface expression of vimentin are possible ways of autoantigen presentation to the immune system.

Hsu, Pei-Chen; Liao, Ya-Fan; Lin, Chin-Li; Lin, Wen-Hao; Liu, Guang-Yaw; Hung, Hui-Chih

2014-01-01

130

Vimentin is involved in peptidylarginine deiminase 2-induced apoptosis of activated jurkat cells.  

PubMed

Peptidylarginine deiminase type 2 (PADI2) deiminates (or citrullinates) arginine residues in protein to citrulline residues in a Ca2+-dependent manner, and is found in lymphocytes and macrophages. Vimentin is an intermediate filament protein and a well-known substrate of PADI2. Citrullinated vimentin is found in ionomycin-induced macrophage apoptosis. Citrullinated vimentin is the target of anti-Sa antibodies, which are specific to rheumatoid arthritis, and play a critical role in the pathogenesis of the disease. To investigate the role of PADI2 in apoptosis, we generated a Jurkat cell line that overexpressed the PADI2 transgene from a tetracycline-inducible promoter, and used a combination of 12-O-tetradecanoylphorbol-13-acetate and ionomycin to activate Jurkat cells. We found that PADI2 overexpression reduced the cell viability of activated Jurkat cells in1a dose- and time-dependent manner. The PADI2-overexpressed and -activated Jurkat cells presented typical manifestations of apoptosis, and exhibited greater levels of citrullinated proteins, including citrullinated vimentin. Vimentin overexpression rescued a portion of the cells from apoptosis. In conclusion, PADI2 overexpression induces apoptosis in activated Jurkat cells. Vimentin is involved in PADI2-induced apoptosis. Moreover, PADI2-overexpressed Jurkat cells secreted greater levels of vimentin after activation, and expressed more vimentin on their cell surfaces when undergoing apoptosis. Through artificially highlighting PADI2 and vimentin, we demonstrated that PADI2 and vimentin participate in the apoptotic mechanisms of activated T lymphocytes. The secretion and surface expression of vimentin are possible ways of autoantigen presentation to the immune system. PMID:24850148

Hsu, Pei-Chen; Liao, Ya-Fan; Lin, Chin-Li; Lin, Wen-Hao; Liu, Guang-Yaw; Hung, Hui-Chih

2014-05-31

131

Improving the active involvement of stakeholders and the public in flood risk management - tools of an involvement strategy and case study results from Austria, Germany and Italy  

NASA Astrophysics Data System (ADS)

The EU Flood Risk Management Directive 2007/60/EC aims at an active involvement of interested parties in the setting up of flood risk management plans and thus calls for more governance-related decision-making. This requirement has two perspectives. On the one hand, there is (1) the question of how decision-makers can improve the quality of their governance process. On the other hand, there is (2) the question of how the public shall be appropriately informed and involved. These questions were the centre of the ERA-Net CRUE-funded project IMRA (integrative flood risk governance approach for improvement of risk awareness) that aimed at an optimisation of the flood risk management process by increasing procedural efficiency with an explicit involvement strategy. To reach this goal, the IMRA project partners developed two new approaches that were implemented in three case study areas for the first time in flood risk management: 1. risk governance assessment tool: An indicator-based benchmarking and monitoring tool was used to evaluate the performance of a flood risk management system in regard to ideal risk governance principles; 2. social milieu approach: The concept of social milieus was used to gain a picture of the people living in the case study regions to learn more about their lifestyles, attitudes and values and to use this knowledge to plan custom-made information and participation activities for the broad public. This paper presents basic elements and the application of two innovative approaches as a part of an "involvement strategy" that aims at the active involvement of all interested parties (stakeholders) for assessing, reviewing and updating flood risk management plans, as formulated in the EU Flood Risk Management Directive 2007/60/EC.

Fleischhauer, M.; Greiving, S.; Flex, F.; Scheibel, M.; Stickler, T.; Sereinig, N.; Koboltschnig, G.; Malvati, P.; Vitale, V.; Grifoni, P.; Firus, K.

2012-09-01

132

Bacillus subtilis polynucleotide phosphorylase 3?-to-5? DNase activity is involved in DNA repair  

PubMed Central

In the presence of Mn2+, an activity in a preparation of purified Bacillus subtilis RecN degrades single-stranded (ss) DNA with a 3? ? 5? polarity. This activity is not associated with RecN itself, because RecN purified from cells lacking polynucleotide phosphorylase (PNPase) does not show the exonuclease activity. We show here that, in the presence of Mn2+ and low-level inorganic phosphate (Pi), PNPase degrades ssDNA. The limited end-processing of DNA is regulated by ATP and is inactive in the presence of Mg2+ or high-level Pi. In contrast, the RNase activity of PNPase requires Mg2+ and Pi, suggesting that PNPase degradation of RNA and ssDNA occur by mutually exclusive mechanisms. A null pnpA mutation (?pnpA) is not epistatic with ?recA, but is epistatic with ?recN and ?ku, which by themselves are non-epistatic. The addA5, ?recO, ?recQ (?recJ), ?recU and ?recG mutations (representative of different epistatic groups), in the context of ?pnpA, demonstrate gain- or loss-of-function by inactivation of repair-by-recombination, depending on acute or chronic exposure to the damaging agent and the nature of the DNA lesion. Our data suggest that PNPase is involved in various nucleic acid metabolic pathways, and its limited ssDNA exonuclease activity plays an important role in RecA-dependent and RecA-independent repair pathways.

Cardenas, Paula P.; Carrasco, Begona; Sanchez, Humberto; Deikus, Gintaras; Bechhofer, David H; Alonso, Juan C

2009-01-01

133

Possible involvement of dihydrofructosazine in the DNA breaking activity of D-glucosamine.  

PubMed

Dehydrochlorination of D-glucosamine (2-amino-2-deoxy-D-glucose) hydrochloride with an anion exchange resin made its DNA breaking activity in plasmid pBR322 much higher, especially in the presence of Cu2+. The sample of anion exchanger-treated D-glucosamine hydrochloride, i.e., HCL-free D-glucosamine sample, showed an absorption maximum at 274 nm on the UV absorption spectrum in water as seen in the case of fructosazine [2,5-bis(D-arabino-tetrahydroxybutyl)pyrazine] one of the dimers of D-glucosamine. On a positive-ion fast atom bombardment (FAB) mass spectrum, the sample showed an ion peak at m/z 323 as a base peak, corresponding to dihydrofructosazine [2,5-bis(D-arabino-tetrahydroxybutyl) dihydropyrazine], which was a precursor of fructosazine, as well as those of D-glucosamine itself (m/z 180) and fructosazine (m/z 321). The DNA strand breaking activity of HCL-free D-glucosamine sample was directly proportional to the peak intensity of m/z 323 ion, while the DNA breaking activity of fructosazine was much weaker than that of HCL-free D-glucosamine sample. 2,5-Dihydro-3,6-dimethylprazine and 2,3-dihydro-5,6-dimethylpyrazine having a dihydropyrazine skeleton the same as dihydrofructosazine showed the same extent of DNA strand breaking activity as did the HCL-free D-glucosamine sample. These results indicated that dihydrofructosazine produced during the dehydrochlorination is closely involved in the DNA breaking activity of HCL-free D-glucosamine sample. PMID:7492977

Kashige, N; Yamaguchi, T; Mishiro, N; Hanazono, H; Miake, F; Watanabe, K

1995-05-01

134

atRA-induced apoptosis of mouse embryonic palate mesenchymal cells involves activation of MAPK pathway  

SciTech Connect

Our previous studies have shown that atRA treatment resulted in cell-cycle block and growth inhibition in mouse embryonic palatal mesenchymal (MEPM). In the current study, gestation day (GD) 13 MEPM cells were used to test the hypothesis that the growth inhibition by atRA is due to apoptosis. The effects of atRA on apoptosis were assessed by performing MTT assay, Cell Death Detection ELISA and flow cytometry, respectively. Data analysis confirmed that atRA treatment induced apoptosis-like cell death, as shown by decreased cell viability and increased fragmented DNA and sub-G1 fraction. atRA-induced apoptosis was associated with upregulation of bcl-2, translocation of bax protein to the mitochondria from the cytosol, activation of caspase-3 and cytochrome c release into cytosol. atRA-induced apoptosis was abrogated by z-DEVD-fmk, a caspase-3 specific inhibitor, and z-VAD-fmk, a general caspase inhibitor, suggesting that the atRA-induced cell death of MEPM cells occurs through the cytochrome c- and caspase-3-dependent pathways. In addition, atRA treatment caused a strong and sustained activation of c-Jun N-terminal kinase (JNK) and p38 kinase (p38), as well as an early but transient activation of extracellular signal-regulated kinase (ERK). Importantly, atRA-induced DNA fragmentation and capase-3 activation were prevented by pretreatment with the JNK inhibitor (SP600125) and the p38 MAPK inhibitor (SB202190), but not by pretreatment with MEK inhibitor (U0126). From these results, we suggest that mitogen-activated protein kinase-dependent pathways is involved in the atRA-induced apoptosis of MEPM cells.

Yu Zengli [Department of Nutrition and Food Hygiene, School of Public Health, Zhengzhou University, No. 40 Daxue Road, Zhengzhou 450052 (China)]. E-mail: yuzengli@263.net; Xing Ying [Stem Cell Research Center, Zhengzhou University, 40 Daxue Road, Zhengzhou 450052 (China)]. E-mail: xingy@zzu.edu.cn

2006-08-15

135

Hepatic microsomal thiol methyltransferase is involved in stereoselective methylation of pharmacologically active metabolite of prasugrel.  

PubMed

Prasugrel, a thienopyridine antiplatelet drug, is converted in animals and humans to the pharmacologically active metabolite R-138727 [(2Z)-{1-[(1RS)-2-cyclopropyl-1-(2-fluorophenyl)-2-oxoethyl]-4-sulfanylpiperidin-3-ylidene}ethanoic acid], which has two chiral centers, occurring as a mixture of four isomers. The RS and RR isomers are more active than the SS and SR isomers (RS > RR > > SR = SS). The pharmacologically active metabolite is further metabolized to an S-methylated metabolite that is the major identified inactive metabolite in humans. In rat, dog, and human liver microsomes supplemented with S-adenosyl methione, the SS and SR isomers of the active metabolite were extensively S-methylated while the RS and RR isomers were not. Addition of 2,3-dichloromethyl benzylamine (50 µM) completely inhibited the S-methylation reaction, indicating that the microsomal and cytosolic thiol methyltransferase but not the cytosolic thiopurine S-methyltransferase is involved in the methylation. The hepatic intrinsic clearance values for methylation of the RS, RR, SS, and SR isomers (ml/min/kg) were 0, 0, 40.4, and 37.6, respectively, in rat liver microsomes, 0, 0, 11.6, and 2.5, respectively, in dog liver microsomes, and 0, 0, 17.3, and 17.7, respectively, in human liver microsomes, indicating that the RS and RR isomers are not methylated in vitro and that the methylation of SS and SR isomers is high with rat > human > dog. This finding in vitro agreed well with the in vivo observation in rats and dogs, where the S-methylated SS and SR isomers were the major metabolites in the plasma whereas negligible amounts of S-methylated RS and RR isomers were detected after intravenous administration of the pharmacologically active metabolites. PMID:24733788

Kazui, Miho; Hagihara, Katsunobu; Izumi, Takashi; Ikeda, Toshihiko; Kurihara, Atsushi

2014-07-01

136

Activation of PPAR{gamma} is not involved in butyrate-induced epithelial cell differentiation  

SciTech Connect

Histone deacetylase-inhibitors affect growth and differentiation of intestinal epithelial cells by inducing expression of several transcription factors, e.g. Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) or vitamin D receptor (VDR). While activation of VDR by butyrate mainly seems to be responsible for cellular differentiation, the activation of PPAR{gamma} in intestinal cells remains to be elucidated. The aim of this study was to determine the role of PPAR{gamma} in butyrate-induced cell growth inhibition and differentiation induction in Caco-2 cells. Treatment with PPAR{gamma} ligands ciglitazone and BADGE (bisphenol A diglycidyl) enhanced butyrate-induced cell growth inhibition in a dose- and time-dependent manner, whereas cell differentiation was unaffected after treatment with PPAR{gamma} ligands rosiglitazone and MCC-555. Experiments were further performed in dominant-negative PPAR{gamma} mutant cells leading to an increase in cell growth whereas butyrate-induced cell differentiation was again unaffected. The present study clearly demonstrated that PPAR{gamma} is involved in butyrate-induced inhibition of cell growth, but seems not to play an essential role in butyrate-induced cell differentiation.

Ulrich, S. [1st Department of Medicine-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Waechtershaeuser, A. [1st Department of Medicine-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Loitsch, S. [1st Department of Medicine-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Knethen, A. von [1st Department of Biochemistry-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Bruene, B. [1st Department of Biochemistry-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Stein, J. [1st Department of Medicine-ZAFES, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany)]. E-mail: j.stein@em.uni-frankfurt.de

2005-10-15

137

Porcine CD3 epsilon: its characterization, expression and involvement in activation of porcine T lymphocytes.  

PubMed Central

The cloning, characterization and expression of porcine CD3 epsilon and establishment of its role in T-cell activation using an anti-porcine CD3 epsilon monoclonal antibody, as described here, provides a first step towards a greater understanding of the porcine immune response. Porcine CD3 epsilon was cloned from a porcine T-cell cDNA library by polymerase chain reaction and found to have up to 72% identity with other CD3 epsilon chains, retaining all the necessary primary structural motifs for correct functioning of porcine CD3 epsilon. When expressed in COS7 cells porcine CD3 epsilon was an intracellularly localized, monomeric 23,000 MW protein exhibiting no evidence of N-glycosylation. A monoclonal antibody, PPT3, recognized expressed porcine CD3 epsilon and activated porcine T cells as demonstrated by stimulation of calcium mobilization, an increase in protein tyrosine phosphorylation and proliferation. These results further reaffirm and identify CD3 epsilon as an important cell surface protein involved in signal transduction of activation signals in porcine T cells. Images Figure 2 Figure 3 Figure 4 Figure 7

Kirkham, P A; Takamatsu, H; Yang, H; Parkhouse, R M

1996-01-01

138

Hormonal signals involved in the regulation of cambial activity, xylogenesis and vessel patterning in trees.  

PubMed

The radial growth of plant stem is based on the development of cribro-vascular cambium tissues. It affects the transport efficiency of water, mineral nutrients and photoassimilates and, ultimately, also plant height. The rate of cambial cell divisions for the assembly of new xylem and phloem tissue primordia and the rate of differentiation of the primordia into mature tissues determine the amount of biomass produced and, in the case of woody species, the wood quality. These complex physiological processes proceed at a rate which depends on several factors, acting at various levels: growth regulators, resource availability and environmental factors. Several hormonal signals and, more recently, further regulatory molecules, have been shown to be involved in the induction and maintenance of cambium and the formation of secondary vascular tissues. The control of xylem cell patterning is of particular interest, because it determines the diameter of xylem vessels, which is central to the efficiency of water and nutrient transport from roots to leaves through the stem and may strongly influence the growth in height of the tree. Increasing scientific evidence have proved the role of other hormones in cambial cell activities and the study of the hormonal signals and their crosstalking in cambial cells may foster our understanding of the dynamics of xylogenesis and of the mechanism of vessel size control along the stem. In this article, the role of the hormonal signals involved in the control of cambium and xylem development in trees and their crosstalking are reviewed. PMID:23553557

Sorce, Carlo; Giovannelli, Alessio; Sebastiani, Luca; Anfodillo, Tommaso

2013-06-01

139

Molecular Mechanisms Involved in the Antitumor Activity of Cannabinoids on Gliomas: Role for Oxidative Stress  

PubMed Central

Cannabinoids, the active components of Cannabis sativa, have been shown to exert antiproliferative and proapoptotic effects on a wide spectrum of tumor cells and tissues. Of interest, cannabinoids have displayed great potency in reducing the growth of glioma tumors, one of the most aggressive CNS tumors, either in vitro or in animal experimental models curbing the growth of xenografts generated by subcutaneous or intrathecal injection of glioma cells in immune-deficient mice. Cannabinoids appear to be selective antitumoral agents as they kill glioma cells without affecting the viability of non-transformed cells. This review will summarize the anti-cancer properties that cannabinoids exert on gliomas and discuss their potential action mechanisms that appear complex, involving modulation of multiple key cell signaling pathways and induction of oxidative stress in glioma cells.

Massi, Paola; Valenti, Marta; Solinas, Marta; Parolaro, Daniela

2010-01-01

140

A novel carotenoid cleavage activity involved in the biosynthesis of Citrus fruit-specific apocarotenoid pigments.  

PubMed

Citrus is the first tree crop in terms of fruit production. The colour of Citrus fruit is one of the main quality attributes, caused by the accumulation of carotenoids and their derivative C30 apocarotenoids, mainly ?-citraurin (3-hydroxy-?-apo-8'-carotenal), which provide an attractive orange-reddish tint to the peel of oranges and Mandarins. Though carotenoid biosynthesis and its regulation have been extensively studied in Citrus fruits, little is known about the formation of C30 apocarotenoids. The aim of this study was to the identify carotenoid cleavage enzyme(s) [CCD(s)] involved in the peel-specific C30 apocarotenoids. In silico data mining revealed a new family of five CCD4-type genes in Citrus. One gene of this family, CCD4b1, was expressed in reproductive and vegetative tissues of different Citrus species in a pattern correlating with the accumulation of C30 apocarotenoids. Moreover, developmental processes and treatments which alter Citrus fruit peel pigmentation led to changes of ?-citraurin content and CCD4b1 transcript levels. These results point to the involvement of CCD4b1 in ?-citraurin formation and indicate that the accumulation of this compound is determined by the availability of the presumed precursors zeaxanthin and ?-cryptoxanthin. Functional analysis of CCD4b1 by in vitro assays unequivocally demonstrated the asymmetric cleavage activity at the 7',8' double bond in zeaxanthin and ?-cryptoxanthin, confirming its role in C30 apocarotenoid biosynthesis. Thus, a novel plant carotenoid cleavage activity targeting the 7',8' double bond of cyclic C40 carotenoids has been identified. These results suggest that the presented enzyme is responsible for the biosynthesis of C30 apocarotenoids in Citrus which are key pigments in fruit coloration. PMID:24006419

Rodrigo, María J; Alquézar, Berta; Alós, Enriqueta; Medina, Víctor; Carmona, Lourdes; Bruno, Mark; Al-Babili, Salim; Zacarías, Lorenzo

2013-11-01

141

Developmental changes in brain activation involved in the production of novel speech sounds in children.  

PubMed

Older children are more successful at producing unfamiliar, non-native speech sounds than younger children during the initial stages of learning. To reveal the neuronal underpinning of the age-related increase in the accuracy of non-native speech production, we examined the developmental changes in activation involved in the production of novel speech sounds using functional magnetic resonance imaging. Healthy right-handed children (aged 6-18 years) were scanned while performing an overt repetition task and a perceptual task involving aurally presented non-native and native syllables. Productions of non-native speech sounds were recorded and evaluated by native speakers. The mouth regions in the bilateral primary sensorimotor areas were activated more significantly during the repetition task relative to the perceptual task. The hemodynamic response in the left inferior frontal gyrus pars opercularis (IFG pOp) specific to non-native speech sound production (defined by prior hypothesis) increased with age. Additionally, the accuracy of non-native speech sound production increased with age. These results provide the first evidence of developmental changes in the neural processes underlying the production of novel speech sounds. Our data further suggest that the recruitment of the left IFG pOp during the production of novel speech sounds was possibly enhanced due to the maturation of the neuronal circuits needed for speech motor planning. This, in turn, would lead to improvement in the ability to immediately imitate non-native speech. Hum Brain Mapp 35:4079-4089, 2014. © 2014 Wiley Periodicals, Inc. PMID:24585739

Hashizume, Hiroshi; Taki, Yasuyuki; Sassa, Yuko; Thyreau, Benjamin; Asano, Michiko; Asano, Kohei; Takeuchi, Hikaru; Nouchi, Rui; Kotozaki, Yuka; Jeong, Hyeonjeong; Sugiura, Motoaki; Kawashima, Ryuta

2014-08-01

142

Functional responses and molecular mechanisms involved in histone-mediated platelet activation.  

PubMed

Histones are highly alkaline proteins found in cell nuclei and they can be released by either dying or inflammatory cells. The recent observations that histones are major components of neutrophil extracellular traps and promote platelet aggregation and platelet-dependent thrombin generation have shown that these proteins are potent prothrombotic molecules. Because the mechanism(s) of platelet activation by histones are not completely understood, we explored the ability of individual recombinant human histones H1, H2A, H2B, H3 and H4 to induce platelet activation as well as the possible molecular mechanisms involved. All histones were substrates for platelet adhesion and spreading and triggered fibrinogen binding, aggregation, von Willebrand factor release, P-selectin and phosphatidylserine (PS) exposure and the formation of platelet-leukocyte aggregates; however, H4 was the most potent. Histone-mediated fibrinogen binding, P-selectin and PS exposure and the formation of mixed aggregates were potentiated by thrombin. Histones induced the activation of ERK, Akt, p38 and NF?B. Accordingly, histone-induced platelet activation was significantly impaired by pretreatment of platelets with inhibitors of ERK (U 0126), PI3K/Akt (Ly 294002), p38 (SB 203580) and NF?B (BAY 11-7082 and Ro 106-9920). Preincubation of platelets with either aspirin or dexamethasone markedly decreased fibrinogen binding and the adhesion mediated by histones without affecting P-selectin exposure. Functional platelet responses induced by H3 and H4, but not H1, H2A and H2B, were partially mediated through interaction with Toll-like receptors -2 and -4. Our data identify histones as important triggers of haemostatic and proinflammatory platelet responses, and only haemostatic responses are partially inhibited by anti-inflammatory drugs. PMID:23965842

Carestia, A; Rivadeneyra, L; Romaniuk, M A; Fondevila, C; Negrotto, S; Schattner, M

2013-10-31

143

Decreased activity of neutrophils in the presence of diferuloylmethane (curcumin) involves protein kinase C inhibition.  

PubMed

Diferuloylmethane (curcumin) has been shown to act beneficially in arthritis, particularly through downregulated expression of proinflammatory cytokines and collagenase as well as through the modulated activities of T lymphocytes and macrophages. In this study its impact on activated neutrophils was investigated both in vitro and in experimental arthritis. Formation of reactive oxygen species in neutrophils was recorded on the basis of luminol- or isoluminol-enhanced chemiluminescence. Phosphorylation of neutrophil protein kinases C alpha and beta II was assessed by Western blotting, using phosphospecific antibodies. Adjuvant arthritis was induced in Lewis rats by heat-killed Mycobacterium butyricum. Diferuloylmethane or methotrexate was administered over a period of 28 days after arthritis induction. Under in vitro conditions, diferuloylmethane (1-100 microM) reduced dose-dependently oxidant formation both at extra- and intracellular level and it effectively reduced protein kinase C activation. Adjuvant arthritis was accompanied by an increased number of neutrophils in blood and by a more pronounced spontaneous as well as PMA (phorbol myristate acetate) stimulated chemiluminescence. Whereas the arthritis-related alterations in neutrophil count and in spontaneous chemiluminescence were not modified by diferuloylmethane, the increased reactivity of neutrophils to PMA was less evident in diferuloylmethane-treated animals. The effects of diferuloylmethane were comparable with those of methotrexate. Diferuloylmethane was found to be a potent inhibitor of neutrophil functions both in vitro and in experimental arthritis. As neutrophils are considered to be cells with the greatest capacity to inflict damage within diseased joints, the observed effects could represent a further mechanism involved in the antirheumatic activity of diferuloylmethane. PMID:19371737

Jancinová, Viera; Perecko, Tomás; Nosál, Radomír; Kostálová, Daniela; Bauerová, Katarína; Drábiková, Katarína

2009-06-10

144

Tryptophan 110, a residue involved in the toxic activity but not in the enzymatic activity of notexin.  

PubMed

We prepared two derivatives of notexin, a phospholipase A2 from Notechis scutatus scutatus venom, by modifying the protein with 2-nitrophenylsulfenylchloride, a tryptophan-specific reagent. One derivative was modified at both tryptophans 20 and 110 whereas the other was modified at tryptophan 20. Evidence based on circular dichroic analysis and antigenicity towards a notexin-specific monoclonal antibody indicated that derivatization at both tryptophans did not affect the tertiary structure of notexin. Concomitant modification of tryptophans 20 and 110 induced a marked decrease in the capacity of notexin to kill mice and to block neuromuscular transmission in the chick biventer cervicis preparation, whereas selective modification at tryptophan 20 had no effect on the lethal properties of notexin. This implies that the decrease in the lethal properties of notexin after derivatization was due to modification at tryptophan 110. However, the diderivatized notexin retained full enzymatic activity, implying that neither tryptophan 20 and tryptophan 110 are involved in the catalytic function of the molecule. We conclude that notexin harbours two functional sites. One of them corresponds to the enzymatic site, whereas the other, which includes tryptophan 110, provides specific toxic characteristics to notexin. By reference to previous crystallographic studies, the relative spatial positions of elements involved in toxicity and the catalytic site, we propose a possible orientation of notexin with respect to its putative membrane-bound target. PMID:2583182

Mollier, P; Chwetzoff, S; Bouet, F; Harvey, A L; Ménez, A

1989-11-01

145

CaMKK? Is Involved in AMP-Activated Protein Kinase Activation by Baicalin in LKB1 Deficient Cell Lines  

PubMed Central

AMP-activated protein kinase (AMPK) plays an important role in mediating energy metabolism and is controlled mainly by two upstream kinases, LKB1 or Ca2+/calmodulin-dependent protein kinase kinase-? (CaMKK?). Previously, we found that baicalin, one of the major flavonoids in a traditional Chinese herb medicine, Scutellaria baicalensis, protects against the development of hepatic steatosis in rats feeding with a high-fat diet by the activation of AMPK, but, the underlying mechanism for AMPK activation is unknown. Here we show that in two LKB1-deficient cells, HeLa and A549 cells, baicalin activates AMPK by ? Thr-172 phosphorylation and subsequent phosphorylation of its downstream target, acetyl CoA carboxylase, at Ser-79, to a similar degree as does in HepG2 cells (that express LKB1). Pharmacologic inhibition of CaMKK? by its selective inhibitor STO-609 markedly inhibits baicalin-induced AMPK activation in both HeLa and HepG2 cells, indicating that CaMKK? is the responsible AMPK kinase. We also show that treatment of baicalin causes a larger increase in intracellular Ca2+ concentration ([Ca2+]i), although the maximal level of [Ca2+]i is lower in HepG2 cells compared to HeLa cells. Chelation of intracellular free Ca2+ by EDTA and EGTA, or depletion of intracellular Ca2+ stores by the endoplasmic reticulum Ca2+-ATPase inhibitor thapsigargin abrogates baicalin-induced activation of AMPK in HeLa cells. Neither cellular ATP nor the production of reactive oxygen species is altered by baicalin. Finally, in HeLa cells, baicalin treatment no longer decreases intracellular lipid accumulation caused by oleic acid after inhibition of CaMKK? by STO-609. These results demonstrate that a potential Ca2+/CaMKK? dependent pathway is involved in the activation of AMPK by baicalin and suggest that CaMKK? likely acts as an upstream kinase of AMPK in response to baicalin.

Wang, Ying; Du, Zhiyan; Liu, Daihua; Guo, Hongxia; Shen, Jingkang; Peng, Hongli

2012-01-01

146

Active involvement of patients in drug research, evaluation, and commercialization: European perspective.  

PubMed

Patients' organizations intervene more and more often in clinical research and the evaluation of medicinal products. Examples of patients' involvement in the initiation, design, recruitment, conduct, and information of clinical trials were only anecdotal until the late 80s. Prior to this date, some rare experiences were reported. At the beginning of the 80s, the AIDS epidemic certainly changed the relation between clinical research and patients, and mechanisms that drove these changes are explained. AIDS activism focused its medical activities to the following domains: (1) to accelerate access to promising new drugs and (2) to contribute to ethical clinical research. The European Medicinal Evaluation Agency (EMEA) created in 1995 offered the opportunity to simplify discussions between European Union regulatory authorities and patients' representatives: a single interlocutor now exists. Interactions between EMEA and patients' representatives vary: they can be more or less structured. Whether intrusion of patients and their representatives in clinical research and pharmaceutical product development had an impact was explored by social sciences researchers. Conclusions are mitigated. PMID:15069992

Houyez, François

2004-01-01

147

Trichoderma Mitogen-Activated Protein Kinase Signaling Is Involved in Induction of Plant Systemic Resistance  

PubMed Central

The role of a mitogen-activated protein kinase (MAPK) TmkA in inducing systemic resistance in cucumber against the bacterial pathogen Pseudomonas syringae pv. lacrymans was investigated by using tmkA loss-of-function mutants of Trichoderma virens. In an assay where Trichoderma spores were germinated in proximity to cucumber roots, the mutants were able to colonize the plant roots as effectively as the wild-type strain but failed to induce full systemic resistance against the leaf pathogen. Interactions with the plant roots enhanced the level of tmkA transcript in T. virens and its homologue in Trichoderma asperellum. At the protein level, we could detect the activation of two forms reacting to the phospho-p44/42 MAPK antibody. Biocontrol experiments demonstrated that the tmkA mutants retain their biocontrol potential against Rhizoctonia solani in soil but are not effective against Sclerotium rolfsii in reducing disease incidence. Our results show that, unlike in many plant-pathogen interactions, Trichoderma TmkA MAPK is not involved in limited root colonization. Trichoderma, however, needs MAPK signaling in order to induce full systemic resistance in the plant.

Viterbo, Ada; Harel, Michal; Horwitz, Benjamin A.; Chet, Ilan; Mukherjee, Prasun K.

2005-01-01

148

Calmodulin-dependent phosphatase, kinases, and transcriptional corepressors involved in T-cell activation  

PubMed Central

Summary The second messenger calcium plays an essential role in mediating the TCR signaling pathway leading to cytokine production and T cell clonal expansion. The immunosuppressive drugs cyclosproin A (CsA) and FK506 have served both as therapeutic agents and as molecular probes for unraveling the protein phosphatase calcineurin as a rate-limiting enzyme involved in the transmission of calcium signal from the cytosol into the nucleus to reprogram gene expression. The use of mouse knockout models has helped to verify and further elucidate the functions of different isoforms of calcineurin in both helper T cell activation and thymocyte development. In addition to calcineurin, three other classes of calmodulin-binding proteins have also been shown to play important roles in calcium signaling in T cells. Thus, Cabin1 and class II HDACs have been found to constitute a novel calcium-signaling module in conjunction with the transcription factor myocyte enhance factor family and the transcriptional coactivator p300 to suppress and activate cytokine gene transcription in a calcium-dependent manner. The calmodulin-dependent protein kinases (CaMK) II and IV were also shown to play negative and positive regulatory functions, respectively, in TCR-mediated cytokine production. The crosstalks among these and other signal transducers in T cells form an extensive non-linear signaling network that dictates the final outcome of the TCR signaling pathway.

Liu, Jun O.

2009-01-01

149

Involvement of an activation protein in the methanol:2-mercaptoethanesulfonic acid methyltransferase reaction in Methanosarcina barkeri.  

PubMed Central

Methanol:5-hydroxybenzimidazolylcobamide methyltransferase (MT1) is the first of two enzymes required for transfer of the methyl group of methanol to 2-mercaptoethanesulfonic acid in Methanosarcina barkeri. MT1 binds the methyl group of methanol to its corrinoid prosthetic group only when the central cobalt atom of the corrinoid is present in the highly reduced Co(I) state. However, upon manipulation of MT1 and even during catalysis, the enzyme becomes inactivated as the result of Co(I) oxidation. Reactivation requires H2, hydrogenase, and ATP. Ferredoxin stimulated the apparent reaction rate of methyl group transfer. Here we report that one more protein fraction was found essential for the overall reaction and, more specifically, for formation of the methylated MT1 intermediate. The more of the protein that was present, the shorter the delay of the start of methyl group transfer. The maximum velocity of methyl transfer was not substantially affected by these varying amounts of protein. This demonstrated that the protein was involved in the activation of MT1. Therefore, it was called methyltransferase activation protein.

Daas, P J; Gerrits, K A; Keltjens, J T; van der Drift, C; Vogels, G D

1993-01-01

150

Brine shrimp larval photoresponses involved in diel vertical migration: Activation by fish mucus and modified amino sugars  

Microsoft Academic Search

Photoresponses involved in the descent phase of nocturnal diel vertical migration of brine shrimp ( Artemia franciscana) naupliar larvae were measured in a laboratory system that mimicked the underwater angular light distribution. The test hypothesis was that kairomones from fish that activate photoresponses involved in DVM include degradation products of polysaccharides in their external mucus. Studies focused on the glycosaminoglycans

Richard B. Forward; Dan Rittschof

1999-01-01

151

78 FR 66970 - In the Matter of Michael J. Buhrman; Order Prohibiting Involvement in NRC-Licensed Activities...  

Federal Register 2010, 2011, 2012, 2013

...IA-13-025] In the Matter of Michael J. Buhrman; Order Prohibiting Involvement...Activities (Effective Immediately) I. Michael J. Buhrman was formerly employed as a senior...effective immediately, that: 1. Michael J. Buhrman is prohibited from engaging...

2013-11-07

152

Modulation of NCC activity by low and high K+ intake: insights into the signaling pathways involved.  

PubMed

Modulation of Na(+)-Cl(-) cotransporter (NCC) activity is essential to adjust K(+) excretion in the face of changes in dietary K(+) intake. We used previously characterized genetic mouse models to assess the role of Ste20-related proline-alanine-rich kinase (SPAK) and with-no-lysine kinase (WNK)4 in the modulation of NCC by K(+) diets. SPAK knockin and WNK4 knockout mice were placed on normal-, low-, or high-K(+)-citrate diets for 4 days. The low-K(+) diet decreased and high-K(+) diet increased plasma aldosterone levels, but both diets were associated with increased phosphorylation of NCC (phospho-NCC, Thr(44)/Thr(48)/Thr(53)) and phosphorylation of SPAK/oxidative stress responsive kinase 1 (phospho-SPAK/OSR1, Ser(383)/Ser(325)). The effect of the low-K(+) diet on SPAK phosphorylation persisted in WNK4 knockout and SPAK knockin mice, whereas the effects of ANG II on NCC and SPAK were lost in both mouse colonies. This suggests that for NCC activation by ANG II, integrity of the WNK4/SPAK pathway is required, whereas for the low-K(+) diet, SPAK phosphorylation occurred despite the absence of WNK4, suggesting the involvement of another WNK (WNK1 or WNK3). Additionally, because NCC activation also occurred in SPAK knockin mice, it is possible that loss of SPAK was compensated by OSR1. The positive effect of the high-K(+) diet was observed when the accompanying anion was citrate, whereas the high-KCl diet reduced NCC phosphorylation. However, the effect of the high-K(+)-citrate diet was aldosterone dependent, and neither metabolic alkalosis induced by bicarbonate, nor citrate administration in the absence of K(+) increased NCC phosphorylation, suggesting that it was not due to citrate-induced metabolic alkalosis. Thus, the accompanying anion might modulate the NCC response to the high-K(+) diet. PMID:24761002

Castañeda-Bueno, María; Cervantes-Perez, Luz Graciela; Rojas-Vega, Lorena; Arroyo-Garza, Isidora; Vázquez, Norma; Moreno, Erika; Gamba, Gerardo

2014-06-15

153

Contrasting early visual cortical activation states causally involved in visual imagery and short-term memory.  

PubMed

Whether visual imagery and visual short-term memory (STM) share the same neural resources, and the extent to which the early visual cortex (V1/V2) is involved in these processes, has been the subject of much debate. Here, we used transcranial magnetic stimulation (TMS) in two separate experiments to contrast the neural states associated with visual imagery and visual STM in the early visual cortex. In Experiment 1, we investigated V1/V2 activation states at the end of the retention phase in a visual imagery and a visual STM task. V1/V2 TMS facilitated performance in both tasks; the finding that imagery and STM interacted with TMS in the same way suggests that the two processes have similar effects on early visual cortical excitability. In Experiment 2, we investigated V1/V2 activation states at the beginning of the retention phase. V1/V2 TMS impaired performance in the visual STM task, whereas it had no effect on the imagery task. Taken together, our findings show that the late phases of the early visual cortical activation state associated with visual imagery and visual STM are similar; differences between the two processes are apparent in the early phases of the tasks. Our results also suggest that the causal role of the early visual cortex in visual STM includes both the initial translation of the visual input into working memory and the subsequent maintenance of the mental representation. Finally, our findings indicate that visual STM sensory recruitment in working memory might act via excitability modulation of V1/V2 neurons. PMID:19788574

Cattaneo, Zaira; Vecchi, Tomaso; Pascual-Leone, Alvaro; Silvanto, Juha

2009-10-01

154

Clock genes outside the suprachiasmatic nucleus involved in manifestation of locomotor activity rhythm in rats.  

PubMed

Chronic treatment of methamphetamine (MAP) in rats desynchronized the locomotor activity rhythm from the light-dark cycle. When the activity rhythm was completely phase-reversed with respect to a light dark-cycle, 24 h profiles were examined for the clock gene (rPer1, rPer2, rBMAL1, rClock) expressions in several brain structures by in situ hybridization, and for the pineal as well as plasma melatonin levels. In the MAP-treated rats, the rPer1 expression in the suprachiasmatic nucleus (SCN) showed a robust circadian rhythm which was essentially identical to that in the control rats. Circadian rhythms in pineal as well as plasma melatonin were not changed significantly in the MAP-treated rats. However, robust circadian rhythms in the rPer1, rPer2 and rBMAL1 expressions detected in the caudate-putamen (CPU) and parietal cortex were completely phase-reversed in the MAP-treated rats, compared with those in the control rats, indicating desynchronization from the SCN rhythm. Such desynchronization was not observed in the circadian rhythms of clock gene expression in the nucleus accumbens and cingulate cortex. The circadian rClock expression rhythm in the MAP-treated rats was not phase-reversed in the CPU and parietal cortex. These findings indicate that the locomotor activity rhythm in rats is directly driven by the pacemaker outside the SCN, in which rPer1, rPer2 and rBMAL1 in the CPU and parietal cortex are involved. PMID:11122332

Masubuchi, S; Honma, S; Abe, H; Ishizaki, K; Namihira, M; Ikeda, M; Honma, K

2000-12-01

155

GSE Is a Maternal Factor Involved in Active DNA Demethylation in Zygotes  

PubMed Central

After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. The dynamic epigenetic changes during early embryo development primarily involve DNA methylation and demethylation. We have previously identified Gse (gonad-specific expression gene) to be expressed specifically in germ cells and early embryos. Its encoded protein GSE is predominantly localized in the nuclei of cells from the zygote to blastocyst stages, suggesting possible roles in the epigenetic changes occurring during early embryo development. Here, we report the involvement of GSE in epigenetic reprogramming of the paternal genome during mouse zygote development. Preferential binding of GSE to the paternal chromatin was observed from pronuclear stage 2 (PN2) onward. A knockdown of GSE by antisense RNA in oocytes produced no apparent effect on the first and second cell cycles in preimplantation embryos, but caused a significant reduction in the loss of 5-methylcytosine (5mC) and the accumulation of 5-hydroxymethylcytosine (5hmC) in the paternal pronucleus. Furthermore, DNA methylation levels in CpG sites of LINE1 transposable elements, Lemd1, Nanog and the upstream regulatory region of the Oct4 (also known as Pou5f1) gene were clearly increased in GSE-knockdown zygotes at mid-pronuclear stages (PN3-4), but the imprinted H19-differential methylated region was not affected. Importantly, DNA immunoprecipitation of 5mC and 5hmC also indicates that knockdown of GSE in zygotes resulted in a significant reduction of the conversion of 5mC to 5hmC on LINE1. Therefore, our results suggest an important role of maternal GSE for mediating active DNA demethylation in the zygote.

Hatanaka, Yuki; Shimizu, Natsumi; Nishikawa, Satoshi; Tokoro, Mikiko; Shin, Seung-Wook; Nishihara, Takuji; Amano, Tomoko; Anzai, Masayuki; Kato, Hiromi; Mitani, Tasuku; Hosoi, Yoshihiko; Kishigami, Satoshi; Matsumoto, Kazuya

2013-01-01

156

DNA Damage Caused by Metal Nanoparticles: the Involvement of Oxidative Stress and Activation of ATM  

PubMed Central

Nanotechnology is a fast growing emerging field, the benefits of which are widely publicized. Our current knowledge of the health effects of metal nanoparticles such as nano-sized cobalt (Nano-Co) and titanium dioxide (Nano-TiO2) is limited but suggests that metal nanoparticles may exert more adverse pulmonary effects as compared with standard-sized particles. To investigate metal nanoparticle-induced genotoxic effects and the potential underlying mechanisms, human lung epithelial cell lines A549 cells were exposed to Nano-Co and Nano-TiO2. Our results showed that exposure of A549 cells to Nano-Co caused reactive oxygen species (ROS) generation that was abolished by pretreatment of cells with ROS inhibitors or scavengers, such as catalase and N-acetyl-L(+)-cysteine (NAC). However, exposure of A549 cells to Nano-TiO2 did not cause ROS generation. Nano-Co caused DNA damage in A549 cells which was reflected by an increase in length, width, and DNA content of the comet tail by Comet assay. Exposure of A549 cells to Nano-Co also caused a dose-and a time- response increased expression of phosphorylated histone H2AX (?-H2AX), Rad51 and phosphorylated p53. These effects were significantly attenuated when A549 cells were pre-treated with catalase or NAC. Nano-TiO2 did not show these effects. These results suggest that oxidative stress may be involved in Nano-Co-induced DNA damage. To further investigate the pathways involved in the Nano-Co-induced DNA damage, we measured the phosphorylation of ataxia telangiectasia mutant (ATM). Our results showed that phosphorylation of ATM was increased when A549 cells were exposed to Nano-Co, and this effect was attenuated when cells were pretreated with catalase or NAC. Pre-treatment of A549 cells with an ATM specific inhibitor, KU55933, significantly abolished Nano-Co-induced DNA damage. Furthermore, pre-treatment of A549 cells with ROS scavengers, such as catalase and NAC, significantly abolished Nano-Co-induced increased expression of phosphorylated ATM. Taken together, oxidative stress and ATM activation are involved in Nano-Co-induced DNA damage. These findings have important implications for understanding the potential health effects of metal nanoparticle exposure.

Wan, Rong; Mo, Yiqun; Feng, Lingfang; Chien, Sufan; Tollerud, David J.; Zhang, Qunwei

2012-01-01

157

DNA damage caused by metal nanoparticles: involvement of oxidative stress and activation of ATM.  

PubMed

Nanotechnology is a fast growing emerging field, the benefits of which are widely publicized. Our current knowledge of the health effects of metal nanoparticles such as nanosized cobalt (Nano-Co) and titanium dioxide (Nano-TiO(2)) is limited but suggests that metal nanoparticles may exert more adverse pulmonary effects as compared with standard-sized particles. To investigate metal nanoparticle-induced genotoxic effects and the potential underlying mechanisms, human lung epithelial A549 cells were exposed to Nano-Co and Nano-TiO(2). Our results showed that exposure of A549 cells to Nano-Co caused reactive oxygen species (ROS) generation that was abolished by pretreatment of cells with ROS inhibitors or scavengers, such as catalase and N-acetyl-L(+)-cysteine (NAC). However, exposure of A549 cells to Nano-TiO(2) did not cause ROS generation. Nano-Co caused DNA damage in A549 cells, which was reflected by an increase in length, width, and DNA content of the comet tail by the Comet assay. Exposure of A549 cells to Nano-Co also caused a dose- and a time-response increased expression of phosphorylated histone H2AX (?-H2AX), Rad51, and phosphorylated p53. These effects were significantly attenuated when A549 cells were pretreated with catalase or NAC. Nano-TiO(2) did not show these effects. These results suggest that oxidative stress may be involved in Nano-Co-induced DNA damage. To further investigate the pathways involved in the Nano-Co-induced DNA damage, we measured the phosphorylation of ataxia telangiectasia mutant (ATM). Our results showed that phosphorylation of ATM was increased when A549 cells were exposed to Nano-Co, and this effect was attenuated when cells were pretreated with catalase or NAC. Pretreatment of A549 cells with an ATM specific inhibitor, KU55933, significantly abolished Nano-Co-induced DNA damage. Furthermore, pretreatment of A549 cells with ROS scavengers, such as catalase and NAC, significantly abolished Nano-Co-induced increased expression of phosphorylated ATM. Taken together, oxidative stress and ATM activation are involved in Nano-Co-induced DNA damage. These findings have important implications for understanding the potential health effects of metal nanoparticle exposure. PMID:22559321

Wan, Rong; Mo, Yiqun; Feng, Lingfang; Chien, Sufan; Tollerud, David J; Zhang, Qunwei

2012-07-16

158

The Effects of Adolescent Activities on Delinquency: A Differential Involvement Approach  

ERIC Educational Resources Information Center

T. Hirschi's (1969, "Causes of Delinquency." University of California Press, Berkeley, CA) control theory proposes that involvement, as an element of the social bond, should reduce delinquency. But, research studies have found that the effect of involvement is rather weak. This study reformulates Hirschi's involvement hypothesis by posing…

Wong, Siu Kwong

2005-01-01

159

EBV reactivation serological profile in primary Sjögren's syndrome: an underlying trigger of active articular involvement?  

PubMed

Antibody to Epstein-Barr virus (EBV) early antigen diffuse (anti-EA-D) is associated with viral replication. However, their possible associations with clinical/therapeutic features in primary Sjögren's syndrome (pSS) were not established. We evaluated 100 pSS patients (American-European Criteria) and 89 age/gender/ethnicity-matched healthy controls. Disease activity was measured by EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI). Antibodies to EBV (anti-VCA IgG/IgM, anti-EBNA-1 IgG, anti-EA-D IgG) were determined by ELISA. Patients and controls had comparable frequencies and mean levels of anti-VCA IgG (90 vs. 86.5 %, p = 0.501; 2.6 ± 1.1 vs. 2.5 ± 1.1 AU/mL, p = 0.737) and anti-EBNA-1 IgG (92 vs. 94.4 %, p = 0.576; 141.3 ± 69.8 vs. 135.6 ± 67.5 RU/mL, p = 0.464). Anti-VCA IgM was negative in all cases. Noteworthy, higher frequency and increased mean levels of anti-EA-D were observed in patients than controls (36 vs. 4.5 %, p < 0.0001; 38.6 ± 57.4 vs. 7.9 ± 26.3 RU/mL, p < 0.0001). Further analysis of patients with (n = 36) and without (n = 64) anti-EA-D revealed comparable age/gender/ethnicity (p ? 0.551), current prednisone dose (4.8 ± 6.9 vs. 5.1 ± 10.4 mg/day, p = 0.319), and current uses of prednisone (52.8 vs. 37.5 %, p = 0.148) and immunosuppressants (44.4 vs. 31.3 %, p = 0.201). ESSDAI values were comparable (p = 0.102), but joint activity was more frequent (25 vs. 9.4 %, p = 0.045) in anti-EA-D positive patients. Anti-EA-D antibodies were not associated with anti-Ro/SSA (p = 1.000), anti-La/SSB (p = 0.652), rheumatoid factor (p = 1.000), anti-?-fodrin (p = 0.390) or antiphospholipid antibodies (p = 0.573), not suggesting cross-reactivity. The higher anti-EA-D frequency associated with joint activity raises the possibility that a subclinical EBV reactivation may trigger or perpetuate the articular involvement in pSS. PMID:22955798

Pasoto, Sandra Gofinet; Natalino, Renato Romera; Chakkour, Henrique Pires; Viana, Vilma Dos Santos Trindade; Bueno, Cleonice; Leon, Elaine Pires; Vendramini, Margarete Borges Gualhardo; Neto, Mauricio Levy; Bonfa, Eloisa

2013-05-01

160

Involvement of TRPA1 activation in acute pain induced by cadmium in mice  

PubMed Central

Background Cadmium (Cd) is an environmental pollutant and acute exposure to it causes symptoms related to pain and inflammation in the airway and gastrointestinal tract, but the underlying mechanisms are still unclear. TRPA1 is a nonselective cation channel expressed in sensory neurons and acts as a nociceptive receptor. Some metal ions such as Ca, Mg, Ba and Zn are reported to modulate TRPA1 channel activity. In the present study, we investigated the effect of Cd on cultured mouse dorsal root ganglion neurons and a heterologous expression system to analyze the effect of Cd at the molecular level. In addition, we examined whether Cd caused acute pain in vivo. Results In wild-type mouse sensory neurons, Cd evoked an elevation of the intracellular Ca concentration ([Ca2+]i) that was inhibited by external Ca removal and TRPA1 blockers. Most of the Cd-sensitive neurons were also sensitive to cinnamaldehyde (a TRPA1 agonist) and [Ca2+]i responses to Cd were absent in TRPA1(?/?) mouse neurons. Heterologous expression of TRPA1 mutant channels that were less sensitive to Zn showed attenuation of Cd sensitivity. Intracellular Cd imaging revealed that Cd entered sensory neurons through TRPA1. The stimulatory effects of Cd were confirmed in TRPA1-expressing rat pancreatic cancer cells (RIN-14B). Intraplantar injection of Cd induced pain-related behaviors that were largely attenuated in TRPA1(?/?) mice. Conclusions Cd excites sensory neurons via activation of TRPA1 and causes acute pain, the mechanism of which may be similar to that of Zn. The present results indicate that TRPA1 is involved in the nociceptive or inflammatory effects of Cd.

2013-01-01

161

Activation of neutral sphingomyelinase is involved in acute hypoxic pulmonary vasoconstriction  

PubMed Central

Aims The mechanisms involved in hypoxic pulmonary vasoconstriction (HPV) are not yet fully defined. The aim of the study was to determine the role of protein kinase C ? (PKC?) and neutral sphingomyelinase (nSMase) in HPV. Methods and results Ceramide content was measured by immunocytochemistry and voltage-gated potassium channel (KV) currents were recorded by the patch clamp technique in isolated rat pulmonary artery smooth muscle cells (PASMC). Contractile responses were analysed in rat pulmonary arteries mounted in a wire myograph. Pulmonary pressure was recorded in anesthetized open-chest rats. Protein and mRNA expression were measured by western blot and RT–PCR, respectively. We found that hypoxia increased ceramide content in PASMC which was abrogated by inhibition of nSMase, but not acid sphingomyelinase (aSMase). The hypoxia-induced vasoconstrictor response in isolated pulmonary arteries and the inhibition of KV currents were strongly reduced by inhibition of PKC? or nSMase but not aSMase. The nSMase inhibitor GW4869 prevented HPV in vivo. The vasoconstrictor response to hypoxia was mimicked by exogenous addition of bacterial Smase and ceramide. nSMase2 mRNA expression was ?10-fold higher in pulmonary compared with mesenteric arteries. In mesenteric arteries, hypoxia failed to increase ceramide but exogenous SMase induced a contractile response. Conclusion nSMase-derived ceramide production and the activation of PKC? are early and necessary events in the signalling cascade of acute HPV.

Cogolludo, Angel; Moreno, Laura; Frazziano, Giovanna; Moral-Sanz, Javier; Menendez, Carmen; Castaneda, Javier; Gonzalez, Constancio; Villamor, Eduardo; Perez-Vizcaino, Francisco

2009-01-01

162

Beta-catenin activation is not involved in sporadic parathyroid carcinomas and adenomas.  

PubMed

Aberrant accumulation of beta-catenin has been found in various types of human tumors. The aim of this study was to evaluate whether Wnt/beta-catenin signaling is activated in parathyroid carcinomas and adenomas. We studied 154 parathyroid tumors (18 carcinomas (13 with distant metastases), six atypical adenomas, and 130 adenomas). Three normal parathyroid tissues were used as control. Direct sequencing of exon 3 of the CTNNB1 gene showed absence of stabilizing mutations in all the tumors. Immunostaining of beta-catenin was performed in all carcinomas and in 66 adenomas (including three atypical). Normal parathyroid showed a homogeneous distinct outer cell membrane staining in the majority of cells and no nuclear staining. A weak cytoplasmic staining was observed in one case. All tumors showed negative nuclear staining. With the exception of one carcinoma, which had a negative membrane staining, all other samples showed a membrane staining which was similar to that of the normal parathyroid. beta-Catenin expression was heterogeneous with a range of positive cells between 5 and 80%, independently of tumor type. Our results suggest that the Wnt/beta-catenin signaling pathway is not involved in the development of parathyroid carcinomas and adenomas. PMID:19755524

Cetani, F; Pardi, E; Banti, C; Collecchi, P; Viacava, P; Borsari, S; Fanelli, G; Naccarato, A G; Saponaro, F; Berti, P; Miccoli, P; Pinchera, A; Marcocci, C

2010-03-01

163

CD36 is involved in astrocyte activation and astroglial scar formation.  

PubMed

Inflammation is an essential component for glial scar formation. However, the upstream mediator(s) that triggers the process has not been identified. Previously, we showed that the expression of CD36, an inflammatory mediator, occurs in a subset of astcotyes in the peri-infarct area where the glial scar forms. This study investigates a role for CD36 in astrocyte activation and glial scar formation in stroke. We observed that the expression of CD36 and glial fibrillary acidic protein (GFAP) coincided in control and injured astrocytes and in the brain. Furthermore, GFAP expression was attenuated in CD36 small interfering RNA transfected astrocytes or in the brain of CD36 knockout (KO) mice, suggesting its involvement in GFAP expression. Using an in-vitro model of wound healing, we found that CD36 deficiency attenuated the proliferation of astrocytes and delayed closure of the wound gap. Furthermore, stroke-induced GFAP expression and scar formation were significantly attenuated in the CD36 KO mice compared with wild type. These findings identify CD36 as a novel mediator for injury-induced astrogliosis and scar formation. Targeting CD36 may serve as a potential strategy to reduce glial scar formation in stroke. PMID:22510603

Bao, Yi; Qin, Luye; Kim, Eunhee; Bhosle, Sangram; Guo, Hengchang; Febbraio, Maria; Haskew-Layton, Renee E; Ratan, Rajiv; Cho, Sunghee

2012-08-01

164

Nanometer Scale Titanium Surface Texturing Are Detected by Signaling Pathways Involving Transient FAK and Src Activations  

PubMed Central

Background It is known that physico/chemical alterations on biomaterial surfaces have the capability to modulate cellular behavior, affecting early tissue repair. Such surface modifications are aimed to improve early healing response and, clinically, offer the possibility to shorten the time from implant placement to functional loading. Since FAK and Src are intracellular proteins able to predict the quality of osteoblast adhesion, this study evaluated the osteoblast behavior in response to nanometer scale titanium surface texturing by monitoring FAK and Src phosphorylations. Methodology Four engineered titanium surfaces were used for the study: machined (M), dual acid-etched (DAA), resorbable media microblasted and acid-etched (MBAA), and acid-etch microblasted (AAMB). Surfaces were characterized by scanning electron microscopy, interferometry, atomic force microscopy, x-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. Thereafter, those 4 samples were used to evaluate their cytotoxicity and interference on FAK and Src phosphorylations. Both Src and FAK were investigated by using specific antibody against specific phosphorylation sites. Principal Findings The results showed that both FAK and Src activations were differently modulated as a function of titanium surfaces physico/chemical configuration and protein adsorption. Conclusions It can be suggested that signaling pathways involving both FAK and Src could provide biomarkers to predict osteoblast adhesion onto different surfaces.

Zambuzzi, Willian F.; Bonfante, Estevam A.; Jimbo, Ryo; Hayashi, Mariko; Andersson, Martin; Alves, Gutemberg; Takamori, Esther R.; Beltrao, Paulo J.; Coelho, Paulo G.; Granjeiro, Jose M.

2014-01-01

165

Involvement of Platelet-Activating Factor in Ultraviolet B-Induced Hyperalgesia  

PubMed Central

Ultraviolet B (UVB) radiation causes cutaneous inflammation. One important clinical consequence of UVB-induced inflammation is increased pain or hyperalgesia, which is likely mediated by enhanced sensitivity of cutaneous sensory neurons. Previous studies have demonstrated that UVB radiation generates the lipid mediator, platelet-activating factor (PAF), as well as oxidized phospholipids that act as PAF-mimetics. These substances exert effects through the PAF receptor (PAF-R). This study was designed to assess whether PAF-R is involved in UVB-induced hyperalgesia. Intradermal injection of carbamoyl PAF (CPAF; 1-hexadecyl-2-N-methylcarbamoyl glycerophosphocholine) resulted in an enhanced response to mechanical stimuli in wild-type mice but not in PAF-R knockout (KO) mice. There was no significant change in paw withdrawal to noxious thermal stimuli in either genotype after intradermal injection of CPAF. Exposure of the hind paw to 1,500 J m?2 UVB radiation caused an increased sensitivity to both mechanical and thermal stimulation in wild-type mice but not in PAF-R KO mice. The thermal hyperalgesia caused by UVB irradiation was inhibited in mice that lacked PAF-R in bone marrow-derived cells. These data demonstrate that the PAF-R is important for UVB-induced hyperalgesia. Further investigation of the role of PAF-R signaling in UVB-induced hyperalgesia could provide better understanding of the pathological processes initiated by UVB-induced skin damage.

Zhang, Qiwei; Sitzman, Leslie A.; Al-Hassani, Mohammad; Cai, Shanbao; Pollok, Karen E.; Travers, Jeffrey B.; Hingtgen, Cynthia M.

2009-01-01

166

High hydrostatic pressure activates transcription factors involved in Saccharomyces cerevisiae stress tolerance.  

PubMed

A number of transcriptional control elements are activated when Saccharomyces cerevisiae cells are submitted to various stress conditions, including high hydrostatic pressure (HHP). Exposure of Saccharomyces cerevisiae cells to HHP results in global transcriptional reprogramming, similar to that observed under other industrial stresses, such as temperature, ethanol and oxidative stresses. Moreover, treatment with a mild hydrostatic pressure renders yeast cells multistress tolerant. In order to identify transcriptional factors involved in coordinating response to high hydrostatic pressure, we performed a time series microarray expression analysis on a wild S. cerevisiae strain exposed to 50 MPa for 30 min followed by recovery at atmospheric pressure (0.1 MPa) for 5, 10 and 15 min. We identified transcription factors and corresponding DNA and RNA motifs targeted in response to hydrostatic pressure. Moreover, we observed that different motif elements are present in the promoters of induced or repressed genes during HHP treatment. Overall, as we have already published, mild HHP treatment to wild yeast cells provides multiple protection mechanisms, and this study suggests that the TFs and motifs identified as responding to HHP may be informative for a wide range of other biotechnological and industrial applications, such as fermentation, that may utilize HHP treatment. PMID:23072392

Bravim, Fernanda; da Silva, Lucas F; Souza, Diego T; Lippman, Soyeon I; Broach, James R; Fernandes, A Alberto R; Fernandes, Patricia M B

2012-12-01

167

Involvement of Trichoderma trichothecenes in the biocontrol activity and induction of plant defense-related genes.  

PubMed

Trichoderma species produce trichothecenes, most notably trichodermin and harzianum A (HA), by a biosynthetic pathway in which several of the involved proteins have significant differences in functionality compared to their Fusarium orthologues. In addition, the genes encoding these proteins show a genomic organization differing from that of the Fusarium tri clusters. Here we describe the isolation of Trichoderma arundinaceum IBT 40837 transformants which have a disrupted or silenced tri4 gene, a gene encoding a cytochrome P450 monooxygenase that oxygenates trichodiene to give rise to isotrichodiol, and the effect of tri4 gene disruption and silencing on the expression of other tri genes. Our results indicate that the tri4 gene disruption resulted in a reduced antifungal activity against Botrytis cinerea and Rhizoctonia solani and also in a reduced ability to induce the expression of tomato plant defense-related genes belonging to the salicylic acid (SA) and jasmonate (JA) pathways against B. cinerea, in comparison to the wild-type strain, indicating that HA plays an important function in the sensitization of Trichoderma-pretreated plants against this fungal pathogen. Additionally, the effect of the interaction of T. arundinaceum with B. cinerea or R. solani and with tomato seedlings on the expressions of the tri genes was studied. PMID:22562989

Malmierca, M G; Cardoza, R E; Alexander, N J; McCormick, S P; Hermosa, R; Monte, E; Gutiérrez, S

2012-07-01

168

Study of the possible mechanisms involved in the mucosal immune system activation by lactic acid bacteria.  

PubMed

The induction of a mucosal immune response is not easy due to the development of oral tolerance, but under some conditions, bacteria can activate this immune system. Antigens administered orally can interact with M cells of Peyer's patches or bind to the epithelial cells. We have demonstrated that certain lactic acid bacteria are able to induce specific secretory immunity, and others will enhance the gut inflammatory immune response. The aim of this work was to establish the reason for these different behaviors and to define possible mechanisms involved in the interaction of lactic acid bacteria at the intestinal level. We studied IgA+ and IgM+ B cells comparatively in bronchus and intestine and CD4+ T cells and IgA anti-lactic acid bacteria antibodies in the intestinal fluid, induced by oral administration of Lactobacillus casei, Lb. delbrueckii ssp. bulgaricus, Lb. acidophilus, Lb. plantarum, Lb. rhamnosus, Lactococcus lactis, and Streptococcus salivarius ssp. thermophilus. The increase in the IgA+ B cells in the bronchus means that these lactic acid bacteria were able to induce the IgA cycle by interaction with M cells from Peyer's patches or intestinal epithelial cells. The IgM+ cells increased when the stimulus did not induce the switch from IgM+ to IgA+. The increase in the CD4+ cells suggests interaction of Peyer's patches and enhancement of the B- and T-cell migration. The anti-lactic acid bacteria antibody is related to the processing and presentation of the microorganisms to the immune cells. We demonstrated that Lb. casei and Lb. plantarum were able to interact with Peyer's patch cells and showed an increase in IgA-, CD4+ cells, and antibodies specific for the stimulating strain. Lactobacillus acidophilus induced gut mucosal activation by interaction with the epithelial cells without increase in the immune cells associated with the bronchus. Although Lb. rhamnosus and Strep. salivarius ssp. thermophilus interact with epithelial cells, they also induced an immune response against their epitopes. Lactococcus lactis and Lb. delbrueckii ssp. bulgaricus induced an increase of IgA+ cells entering the IgA cycle but not CD4+ cells; thus, these bacteria would have been bound to epithelial cells that activated B lymphocytes without processing and presenting of their epitopes. We did not determine specific antibodies against Lc. lactis or Lb. bulgaricus. PMID:10386296

Perdigón, G; Vintiñi, E; Alvarez, S; Medina, M; Medici, M

1999-06-01

169

Rural Schooling in Georgia: The Experiences of a Minority Community Service Organization Involved in Local School Decision-Making Activities  

ERIC Educational Resources Information Center

This dissertation study was a descriptive case study of a minority community service organization whose members were actively involved in local school decision-making and activities in a rural Northeast Georgia community. Rural schools face unique challenges in light of current educational trends. To address the challenges, rural schools must…

Lowe, Cynthia Louise Altman

2010-01-01

170

Possible Involvement of Ca2+ Activated K+ Channels, SK Channel, in the Quercetin-Induced Vasodilatation  

PubMed Central

Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the Ca2+ activated K+ (KCa) channel was examined. Pretreatment with NE (5 µM) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring strips (3 mm) at 36.5?. Quercetin (0.1 to 100 µM) relaxed the NE-induced vasoconstrictions in a concentration-dependent manner. NO synthesis (NOS) inhibitor, NG-monomethyl-L-arginine acetate (L-NMMA), at 100 µM reduced the quercetin (100 µM)-induced vasodilatation from 97.8±3.7% (n=10) to 78.0±11.6% (n=5, p<0.05). Another NOS inhibitor, L-NG-nitro arginine methyl ester (L-NAME), at 100 µM also had the similar effect. In the presence of both 100 µM L-NMMA and 10 µM indomethacin, the quercetin-induced vasodilatation was further attenuated by 100 µM tetraethylammonium (TEA, a KCa channel inhibitor). Also TEA decreased the quercetin-induced vasodilatation in endothelium-denuded rat aorta. Used other KCa channel inhibitors, the quercetin-induced vasodilatation was attenuated by 0.3 µM apamin (a SK channel inhibitor), but not by 30 nM charybdotoxin (a BK and IK channel inhibitor). Quercetin caused a concentration-dependent vasodilatation, due to the endothelium-dependent and -independent actions. Also quercetin contributes to the vasodilatation selectively with SK channel on smooth muscle.

Nishida, Seiichiro

2009-01-01

171

Massive calcium-activated endocytosis without involvement of classical endocytic proteins  

PubMed Central

We describe rapid massive endocytosis (MEND) of >50% of the plasmalemma in baby hamster kidney (BHK) and HEK293 cells in response to large Ca transients. Constitutively expressed Na/Ca exchangers (NCX1) are used to generate Ca transients, whereas capacitance recording and a membrane tracer dye, FM 4–64, are used to monitor endocytosis. With high cytoplasmic adenosine triphosphate (ATP; >5 mM), Ca influx causes exocytosis followed by MEND. Without ATP, Ca transients cause only exocytosis. MEND can then be initiated by pipette perfusion of ATP, and multiple results indicate that ATP acts via phosphatidylinositol-bis 4,5-phosphate (PIP2) synthesis: PIP2 substitutes for ATP to induce MEND. ATP-activated MEND is blocked by an inositol 5-phosphatase and by guanosine 5?-[?-thio]triphosphate (GTP?S). Block by GTP?S is overcome by the phospholipase C inhibitor, U73122, and PIP2 induces MEND in the presence of GTP?S. MEND can occur in the absence of ATP and PIP2 when cytoplasmic free Ca is clamped to 10 µM or more by Ca-buffered solutions. ATP-independent MEND occurs within seconds during Ca transients when cytoplasmic solutions contain polyamines (e.g., spermidine) or the membrane is enriched in cholesterol. Although PIP2 and cholesterol can induce MEND minutes after Ca transients have subsided, polyamines must be present during Ca transients. MEND can reverse over minutes in an ATP-dependent fashion. It is blocked by brief ?-methylcyclodextrin treatments, and tests for involvement of clathrin, dynamins, calcineurin, and actin cytoskeleton were negative. Therefore, we turned to the roles of lipids. Bacterial sphingomyelinases (SMases) cause similar MEND responses within seconds, suggesting that ceramide may be important. However, Ca-activated MEND is not blocked by reagents that inhibit SMases. MEND is abolished by the alkylating phospholipase A2 inhibitor, bromoenol lactone, whereas exocytosis remains robust, and Ca influx causes MEND in cardiac myocytes without preceding exocytosis. Thus, exocytosis is not prerequisite for MEND. From these results and two companion studies, we suggest that Ca promotes the formation of membrane domains that spontaneously vesiculate to the cytoplasmic side.

Lariccia, Vincenzo; Fine, Michael; Magi, Simona; Yaradanakul, Alp; Llaguno, Marc C.

2011-01-01

172

Spontaneous activity in the developing gerbil auditory cortex in vivo involves GABAergic transmission  

PubMed Central

A salient feature of the developing brain is that spontaneous oscillations (SOs) and waves may influence the emergence of synaptic connections. Whilst gamma-amino butyric acid (GABA) produces depolarization and may support SOs in the neurons of developing rodents, it elicits hyperpolarization and diminishes SOs in developing gerbil auditory cortex (ACx). Therefore, we asked whether SOs exist in developing gerbil ACx in vivo and if GABAergic involvement can be manipulated. In vivo extracellular recordings in P3-5 ACx revealed SOs with longer burst durations and shorter inter-event intervals compared to ACx SOs in slices. ACx was then validated by gross anatomical features and lesions created at the in vivo recording site that corresponded with the electrophysiological coordinates of thalamorecipient ACx in slices. Further, NeuroVue Red, a lipophilic dye loaded at the in vivo recording sites, stained anatomically identifiable fiber tracks between the ACx and the auditory thalamus, medial geniculate body (MG). Separately, to chronically perturb GABAergic role in SOs, P2-5 pups were administered daily with GABAA receptor blocker, bicuculline (BIC). We then recorded from P14-17 ACx neurons in slices generated after hearing onset. ACx neurons from BIC-administered pups exhibited spontaneous action potentials in contrast to subthreshold synaptic potentials in neurons from sham-injected animals. Finally, to elucidate whether the gap junction blocker mefloquine (MFQ) previously shown to dampen ACx SOs in slices affected GABAergic transmission, MFQ was acutely applied in P3-5 slices while spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded. Whereas MFQ increased the amplitude and frequency of sIPSCs in ACx neurons, the broad-spectrum gap junction blocker carbenoxolone decreased sIPSC amplitudes only. Together, we show that P2-5 gerbil ACx can endogenously generate SOs in vivo. Persistence of activity in ACx in P14-17 slices from pups administered with BIC at P2-5 implies that inhibitory GABAergic activity linked with gap-junction participates in the maturation of ACx.

Kotak, Vibhakar C.; Pendola, L. Martin; Rodriguez-Contreras, Adrian

2012-01-01

173

The Association between Students' Research Involvement in Medical School and Their Postgraduate Medical Activities.  

ERIC Educational Resources Information Center

A survey of 567 graduates of 3 medical schools (Pennsylvania State University, University of Connecticut, and University of Massachusetts) showed medical school research involvement to be strongly associated with postgraduate research involvement. In residency specialty training, fellowship training, academic appointments, career practice choices,…

Segal, Scott; And Others

1990-01-01

174

Self-definitions of Gang Membership and Involvement in Delinquent Activities  

Microsoft Academic Search

There is significant disagreement among researchers as to the appropriate concep- tual and operational definitions of gang membership. One of the key issues involves the validity of allowing respondents to identify themselves as gang members. This re- search examines the construct validity of gang membership by examining the relation- ship between various methods of operationalizing gang membership and delinquent involvement.

BETH BJERREGAARD

2002-01-01

175

Involving Parents of Young Children in Science, Math and Literacy Activities.  

ERIC Educational Resources Information Center

A summer parent involvement project was set up in a Chicago inner city public school in a Hispanic neighborhood. The eight-session program was intended to help parents: (1) become involved with the school program by becoming comfortable with the school setting; (2) enjoy reading and writing and replicate these experiences with their children; (3)…

Landerholm, Elizabeth; And Others

176

Involvement of Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) and its Receptors in the Mechanism of Antidepressant Action  

Microsoft Academic Search

Recent studies have suggested antidepressant involvement in synaptic plasticity, possibly mediated by neurotrophins and neuropeptides.\\u000a Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide and neuromodulator. Since its discovery, PACAP\\u000a has been extensively investigated with regard to its neurotrophic properties including regulation of brain-derived neurotrophic\\u000a factor (BDNF) expression, a neurotrophin postulated to be involved in the mechanism of antidepressant action

Michal Reichenstein; Moshe Rehavi; Albert Pinhasov

2008-01-01

177

Effect of reserpine on the activity of adrenal enzymes involved in the synthesis of adrenaline  

PubMed Central

1. After administration of reserpine to rats, the tyrosine hydroxylase (TH) and phenylethanolamine-N-methyl transferase (PNMT) activity in their adrenal glands was found to be increased under in vitro conditions. 2. The increase in TH activity occurred at 12-18 h after reserpine whereas the PNMT activity increased at 30 hours. Unlike the TH, the increase in PNMT activity did not appear to be neuronally mediated since ganglion blockade by chlorisondamine failed to antagonize the reserpine-induced increase in PNMT activity. The increase in PNMT activity may be a response to increased utilization of catecholamines. 3. Hypophysectomy resulted in a diminution of the activities of both enzymes; the activity of TH, but not of PNMT, could be partially restored by reserpine. ACTH restored the activities of both enzymes almost to normal. 4. The differential effect of reserpine suggests that the activities of these two enzymes are controlled by different mechanisms.

Bhagat, B.; Burke, W. J.; Davis, J. W.

1971-01-01

178

Epileptiform Activity Induction With Electrolyte Imbalance in Brain Slices: Mechanisms Involved in Control.  

National Technical Information Service (NTIS)

Epilepsy is a disorder of recurrent seizure activity caused by rhythmic firing of neurons. Epileptiform activity can be generated by incubating brain slices in magnesium-free artificial cerebrospinal fluid (ACSF). In the present study, epileptiform discha...

H. Saybasili R. B. Arslan

2001-01-01

179

Video Games and Children: Effects on Leisure Activities, Schoolwork, and Peer Involvement.  

ERIC Educational Resources Information Center

Measures the indirect effect a home video system has on children's leisure activities, school work, and peer contacts. Concludes that owning a video game does not greatly alter a child's activities. (HOD)

Creasey, Gary L; Myers, Barbara J

1986-01-01

180

Lack of involvement of mitochondrial factors in caspase activation in a Drosophila cell-free system  

Microsoft Academic Search

Although mitochondrial proteins play well-defined roles in caspase activation in mammalian cells, the role of mitochondrial factors in caspase activation in Drosophila is unclear. Using cell-free extracts, we demonstrate that mitochondrial factors play no apparent role in Drosophila caspase activation. Cytosolic extract from apoptotic S2 cells, in which caspases were inhibited, induced caspase activation in cytosolic extract from normal S2

J C Means; I Muro; R J Clem

2006-01-01

181

Parental Involvement in Active Transport to School Initiatives: A Multi-Site Case Study  

ERIC Educational Resources Information Center

Background: Increasing physical activity in youth is a recommended approach to curbing the childhood obesity epidemic. One way to help increase children's daily activity is to promote active transportation to and from school (ATS). Purpose: The purpose of this case study was to explore parental perception of, and participation in, ATS initiatives.…

Eyler, Amy; Baldwin, Julie; Carnoske, Cheryl; Nickelson, Jan; Troped, Philip; Steinman, Lesley; Pluto, Delores; Litt, Jill; Evenson, Kelly; Terpstra, Jennifer; Brownson, Ross; Schmid, Thomas

2008-01-01

182

Unique Residues Involved in Activation of the Multitasking Protease/Chaperone HtrA from Chlamydia trachomatis  

PubMed Central

DegP, a member of the HtrA family of proteins, conducts critical bacterial protein quality control by both chaperone and proteolysis activities. The regulatory mechanisms controlling these two distinct activities, however, are unknown. DegP activation is known to involve a unique mechanism of allosteric binding, conformational changes and oligomer formation. We have uncovered a novel role for the residues at the PDZ1:protease interface in oligomer formation specifically for chaperone substrates of Chlamydia trachomatis HtrA (DegP homolog). We have demonstrated that CtHtrA proteolysis could be activated by allosteric binding and oligomer formation. The PDZ1 activator cleft was required for the activation and oligomer formation. However, unique to CtHtrA was the critical role for residues at the PDZ1:protease interface in oligomer formation when the activator was an in vitro chaperone substrate. Furthermore, a potential in vivo chaperone substrate, the major outer membrane protein (MOMP) from Chlamydia, was able to activate CtHtrA and induce oligomer formation. Therefore, we have revealed novel residues involved in the activation of CtHtrA which are likely to have important in vivo implications for outer membrane protein assembly.

Huston, Wilhelmina M.; Tyndall, Joel D. A.; Lott, William B.; Stansfield, Scott H.; Timms, Peter

2011-01-01

183

77 FR 49835 - Order Prohibiting Involvement in NRC-Licensed Activities; In the Matter of Mr. Joseph Quintanilla  

Federal Register 2010, 2011, 2012, 2013

...Prohibiting Involvement in NRC-Licensed Activities; In the Matter of Mr. Joseph Quintanilla I Mr. Joseph Quintanilla is a radiographer...Quintanilla indicated that he was aware the camera was outside of the dark room and did not contest that apparent violation. Mr....

2012-08-17

184

Predicting Adolescents' Organized Activity Involvement: The Role of Maternal Depression History, Family Relationship Quality, and Adolescent Cognitions  

ERIC Educational Resources Information Center

Although the potential benefits of organized activity involvement during high school have been documented, little is known about what familial and individual characteristics are associated with higher levels of participation. Using structural equation modeling, this longitudinal study examined the extent to which maternal depression history (i.e.,…

Bohnert, Amy M.; Martin, Nina C.; Garber, Judy

2007-01-01

185

Lipopolysaccharide stimulates adrenal steroidogenesis in rodent cells by a NF?B-dependent mechanism involving COX2 activation  

Microsoft Academic Search

Stimulation of adrenal steroidogenesis is involved in the HPA response to exogenous noxa. Although inflammatory cytokines can mediate the LPS-triggered activation of the HPA, direct effects of LPS on glucocorticoid release have been described. Present studies were undertaken to characterize the molecular mechanisms underlying the effect of LPS on steroid secretion in isolated rodent adrenal cells, assessing the participation of

C. Martinez Calejman; F. Astort; J. M. Di Gruccio; E. M. Repetto; M. Mercau; E. Giordanino; R. Sanchez; O. Pignataro; P. Arias; C. B. Cymeryng

2011-01-01

186

Primary somatosensory cortex is actively involved in pain processing in human  

Microsoft Academic Search

We recorded somatosensory evoked magnetic fields (SEFs) by a whole head magnetometer to elucidate cortical receptive areas involved in pain processing, focusing on the primary somatosensory cortex (SI), following painful CO2 laser stimulation of the dorsum of the left hand in 12 healthy human subjects. In seven subjects, three spatially segregated cortical areas (contralateral SI and bilateral second (SII) somatosensory

Masutaro Kanda; Takashi Nagamine; Akio Ikeda; Shinji Ohara; Takeharu Kunieda; Naohito Fujiwara; Shogo Yazawa; Nobukatsu Sawamoto; Riki Matsumoto; Waro Taki; Hiroshi Shibasaki

2000-01-01

187

Undergraduate Involvement in Extracurricular Activities and Leadership Development in College of Agriculture and Life Sciences Students  

ERIC Educational Resources Information Center

The purpose of this study was to identify and describe experiences of undergraduate extracurricular involvement that result in increased leadership development. Senior students in the College of Agriculture and Life Sciences at Iowa State University completed an online questionnaire about their extracurricular experiences. Leadership development…

Foreman, Elizabeth A.; Retallick, Michael S.

2012-01-01

188

Belinostat-induced apoptosis and growth inhibition in pancreatic cancer cells involve activation of TAK1-AMPK signaling axis  

SciTech Connect

Highlights: •Belinostat activates AMPK in cultured pancreatic cancer cells. •Activation of AMPK is important for belinostat-induced cytotoxic effects. •ROS and TAK1 are involved in belinostat-induced AMPK activation. •AMPK activation mediates mTOR inhibition by belinostat. -- Abstract: Pancreatic cancer accounts for more than 250,000 deaths worldwide each year. Recent studies have shown that belinostat, a novel pan histone deacetylases inhibitor (HDACi) induces apoptosis and growth inhibition in pancreatic cancer cells. However, the underlying mechanisms are not fully understood. In the current study, we found that AMP-activated protein kinase (AMPK) activation was required for belinostat-induced apoptosis and anti-proliferation in PANC-1 pancreatic cancer cells. A significant AMPK activation was induced by belinostat in PANC-1 cells. Inhibition of AMPK by RNAi knockdown or dominant negative (DN) mutation significantly inhibited belinostat-induced apoptosis in PANC-1 cells. Reversely, AMPK activator AICAR and A-769662 exerted strong cytotoxicity in PANC-1 cells. Belinostat promoted reactive oxygen species (ROS) production in PANC-1 cells, increased ROS induced transforming growth factor-?-activating kinase 1 (TAK1)/AMPK association to activate AMPK. Meanwhile, anti-oxidants N-Acetyl-Cysteine (NAC) and MnTBAP as well as TAK1 shRNA knockdown suppressed belinostat-induced AMPK activation and PANC-1 cell apoptosis. In conclusion, we propose that belinostat-induced apoptosis and growth inhibition require the activation of ROS-TAK1-AMPK signaling axis in cultured pancreatic cancer cells.

Wang, Bing, E-mail: wangbin69@yahoo.com; Wang, Xin-bao; Chen, Li-yu; Huang, Ling; Dong, Rui-zen

2013-07-19

189

A qualitative study of the activities performed by people involved in clinical decision support: recommended practices for success  

PubMed Central

Objective To describe the activities performed by people involved in clinical decision support (CDS) at leading sites. Materials and methods We conducted ethnographic observations at seven diverse sites with a history of excellence in CDS using the Rapid Assessment Process and analyzed the data using a series of card sorts, informed by Linstone's Multiple Perspectives Model. Results We identified 18 activities and grouped them into four areas. Area 1: Fostering relationships across the organization, with activities (a) training and support, (b) visibility/presence on the floor, (c) liaising between people, (d) administration and leadership, (e) project management, (f) cheerleading/buy-in/sponsorship, (g) preparing for CDS implementation. Area 2: Assembling the system with activities (a) providing technical support, (b) CDS content development, (c) purchasing products from vendors (d) knowledge management, (e) system integration. Area 3: Using CDS to achieve the organization's goals with activities (a) reporting, (b) requirements-gathering/specifications, (c) monitoring CDS, (d) linking CDS to goals, (e) managing data. Area 4: Participation in external policy and standards activities (this area consists of only a single activity). We also identified a set of recommendations associated with these 18 activities. Discussion All 18 activities we identified were performed at all sites, although the way they were organized into roles differed substantially. We consider these activities critical to the success of a CDS program. Conclusions A series of activities are performed by sites strong in CDS, and sites adopting CDS should ensure they incorporate these activities into their efforts.

Wright, Adam; Ash, Joan S; Erickson, Jessica L; Wasserman, Joe; Bunce, Arwen; Stanescu, Ana; St Hilaire, Daniel; Panzenhagen, Morgan; Gebhardt, Eric; McMullen, Carmit; Middleton, Blackford; Sittig, Dean F

2014-01-01

190

Bacillus subtilis polynucleotide phosphorylase 3'-to-5' DNase activity is involved in DNA repair  

Microsoft Academic Search

In the presence of Mn2Y, an activity in a preparation of purified Bacillus subtilis RecN degrades single- stranded (ss) DNA with a 3' ! 5' polarity. This activ- ity is not associated with RecN itself, because RecN purified from cells lacking polynucleotide phosphorylase (PNPase) does not show the exonu- clease activity. We show here that, in the presence of Mn2Y

Paula P. Cardenas; Begona Carrasco; Humberto Sanchez; Gintaras Deikus; David H. Bechhofer; Juan C. Alonso

2009-01-01

191

Activation of AMPK by Bitter Melon Triterpenoids Involves CaMKK?  

PubMed Central

We recently showed that bitter melon-derived triterpenoids (BMTs) activate AMPK and increase GLUT4 translocation to the plasma membrane in vitro, and improve glucose disposal in insulin resistant models in vivo. Here we interrogated the mechanism by which these novel compounds activate AMPK, a leading anti-diabetic drug target. BMTs did not activate AMPK directly in an allosteric manner as AMP or the Abbott compound (A-769662) does, nor did they activate AMPK by inhibiting cellular respiration like many commonly used anti-diabetic medications. BMTs increased AMPK activity in both L6 myotubes and LKB1-deficient HeLa cells by 20–35%. Incubation with the CaMKK? inhibitor, STO-609, completely attenuated this effect suggesting a key role for CaMKK? in this activation. Incubation of L6 myotubes with the calcium chelator EGTA-AM did not alter this activation suggesting that the BMT-dependent activation was Ca2+-independent. We therefore propose that CaMKK? is a key upstream kinase for BMT-induced activation of AMPK.

Iseli, Tristan J.; Turner, Nigel; Zeng, Xiao-Yi; Cooney, Gregory J.; Kraegen, Edward W.; Yao, Sheng; Ye, Yang; James, David E.; Ye, Ji-Ming

2013-01-01

192

Activated spinal astrocytes are involved in the maintenance of chronic widespread mechanical hyperalgesia after cast immobilization  

PubMed Central

Background In the present study, we examined spinal glial cell activation as a central nervous system mechanism of widespread mechanical hyperalgesia in rats that experienced chronic post-cast pain (CPCP) 2 weeks after cast immobilization. Activated spinal microglia and astrocytes were investigated immunohistologically in lumbar and coccygeal spinal cord segments 1 day, 5 weeks, and 13 weeks following cast removal. Results In the lumbar cord, astrocytes were activated after microglia. Astrocytes also were activated after microglia in the coccygeal cord, but with a delay that was longer than that observed in the lumbar cord. This activation pattern paralleled the observation that mechanical hyperalgesia occurred in the hindleg or the hindpaw before the tail. The activating transcription factor 3 (ATF3) immune response in dorsal root ganglia (DRG) on the last day of cast immobilization suggested that nerve damage might not occur in CPCP rats. The neural activation assessed by the phosphorylated extracellular signal-regulated kinase (pERK) immune response in DRG arose 1 day after cast removal. In addition, L-?-aminoadipate (L-?-AA), an inhibitor of astrocyte activation administered intrathecally 5 weeks after cast removal, inhibited mechanical hyperalgesia in several body parts including the lower leg skin and muscles bilaterally, hindpaws, and tail. Conclusions These findings suggest that activation of lumbar cord astrocytes is an important factor in widespread mechanical hyperalgesia in CPCP.

2014-01-01

193

Activity-Dependent Dendritic Spine Shrinkage and Growth Involve Downregulation of Cofilin via Distinct Mechanisms  

PubMed Central

A current model posits that cofilin-dependent actin severing negatively impacts dendritic spine volume. Studies suggested that increased cofilin activity underlies activity-dependent spine shrinkage, and that reduced cofilin activity induces activity-dependent spine growth. We suggest instead that both types of structural plasticity correlate with decreased cofilin activity. However, the mechanism of inhibition determines the outcome for spine morphology. RNAi in rat hippocampal cultures demonstrates that cofilin is essential for normal spine maintenance. Cofilin-F-actin binding and filament barbed-end production decrease during the early phase of activity-dependent spine shrinkage; cofilin concentration also decreases. Inhibition of the cathepsin B/L family of proteases prevents both cofilin loss and spine shrinkage. Conversely, during activity-dependent spine growth, LIM kinase stimulates cofilin phosphorylation, which activates phospholipase D-1 to promote actin polymerization. These results implicate novel molecular mechanisms and prompt a revision of the current model for how cofilin functions in activity-dependent structural plasticity.

Calabrese, Barbara; Saffin, Jean-Michel; Halpain, Shelley

2014-01-01

194

High Inorganic Triphosphatase Activities in Bacteria and Mammalian Cells: Identification of the Enzymes Involved  

PubMed Central

Background We recently characterized a specific inorganic triphosphatase (PPPase) from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this family are annotated as predicted adenylate cyclases, because one of the founding members is CyaB adenylate cyclase from A. hydrophila. The aim of the present study is to determine whether other members of the CYTH protein family also have a PPPase activity, if there are PPPase activities in animal tissues and what enzymes are responsible for these activities. Methodology/Principal Findings Recombinant enzymes were expressed and purified as GST- or His-tagged fusion proteins and the enzyme activities were determined by measuring the release of inorganic phosphate. We show that the hitherto uncharacterized E. coli CYTH protein ygiF is a specific PPPase, but it contributes only marginally to the total PPPase activity in this organism, where the main enzyme responsible for hydrolysis of inorganic triphosphate (PPPi) is inorganic pyrophosphatase. We further show that CyaB hydrolyzes PPPi but this activity is low compared to its adenylate cyclase activity. Finally we demonstrate a high PPPase activity in mammalian and quail tissue, particularly in the brain. We show that this activity is mainly due to Prune, an exopolyphosphatase overexpressed in metastatic tumors where it promotes cell motility. Conclusions and General Significance We show for the first time that PPPase activities are widespread in bacteria and animals. We identified the enzymes responsible for these activities but we were unable to detect significant amounts of PPPi in E. coli or brain extracts using ion chromatography and capillary electrophoresis. The role of these enzymes may be to hydrolyze PPPi, which could be cytotoxic because of its high affinity for Ca2+, thereby interfering with Ca2+ signaling.

Lakaye, Bernard; Servais, Anne-Catherine; Scholer, Georges; Fillet, Marianne; Elias, Benjamin; Derochette, Jean-Michel; Crommen, Jacques; Wins, Pierre; Bettendorff, Lucien

2012-01-01

195

Lipopolysaccharide stimulates adrenal steroidogenesis in rodent cells by a NF?B-dependent mechanism involving COX-2 activation.  

PubMed

Stimulation of adrenal steroidogenesis is involved in the HPA response to exogenous noxa. Although inflammatory cytokines can mediate the LPS-triggered activation of the HPA, direct effects of LPS on glucocorticoid release have been described. Present studies were undertaken to characterize the molecular mechanisms underlying the effect of LPS on steroid secretion in isolated rodent adrenal cells, assessing the participation of NF?B and COX-2 activities in this response. Our results show that LPS treatment stimulates steroidogenesis in murine and rat adrenocortical cells, and that Y1 cells express the binding-transducing complex TLR-4/CD14/MD-2, as demonstrated by RT-PCR. NF?B activity and COX-2 protein levels are increased in this cell line by LPS treatment, and pharmacologic and molecular manipulation of the NF?B pathway significantly affected both COX-2 protein levels and steroid production. Finally, pharmacological inhibition of COX-2 activity significantly impairs steroid production. Thus, our results strongly suggest that the mechanism involved in the stimulation of steroidogenesis by LPS in rodent adrenal cells involves the activation of the NF?B signaling pathway and the induction of COX-2. PMID:21300135

Martinez Calejman, C; Astort, F; Di Gruccio, J M; Repetto, E M; Mercau, M; Giordanino, E; Sanchez, R; Pignataro, O; Arias, P; Cymeryng, C B

2011-04-30

196

Teacher-Involved Conversations with Young Children during Small Group Activity  

ERIC Educational Resources Information Center

This qualitative study examines the conversations of two preschool teachers with two- and three-year-old children during small-group activity settings in two high-quality child development centers. Using interviews, observations and videotaping of small-group activities, the conversations are characterized in terms of the kind and function of…

Durden, Tonia; Dangel, Julie Rainer

2008-01-01

197

75 FR 69630 - Impact of Implementation of the Chemical Weapons Convention on Commercial Activities Involving...  

Federal Register 2010, 2011, 2012, 2013

...seeking public comments on the impact that implementation of the...CWCIA, or CWCR have potential impacts on commercial activities whenever...qualitative assessment of the impact of the CWC on such activities...public comments on the BIS Freedom of Information Act...

2010-11-15

198

How does conformational flexibility influence key structural features involved in activation of anaplastic lymphoma kinase?  

PubMed

Anaplastic Lymphoma Kinase (ALK) plays a major role in developing tumor processes and therefore has emerged as a validated therapeutic target. Applying atomistic molecular dynamics simulations on the wild type enzyme and the nine most frequently occurring and clinically important activation mutants we revealed important conformational effects on key interactions responsible for the activation of the enzyme. PMID:24675991

Karabencheva, Tatyana G; Lee, Christian C; Black, Gary W; Donev, Rossen; Christov, Christo Z

2014-06-01

199

Involvement of Cot activity in the proliferation of ALCL lymphoma cells  

SciTech Connect

Highlights: {yields} We show here that ALCL lymphoma cell lines present high levels of Cot (MAP3K8). {yields} We show that Cot mediates the constitutive Erk1/2 activation in SUDHL-1 cells. {yields} Inhibition of Cot activity reduces the number of cell divisions in SUDHL-1 cells. {yields} Cot controls the activation state of p70 S6K and JunB expression in SUDHL-1 cells. -- Abstract: Anaplastic large-cell lymphoma (ALCL) cells overexpress CD30 on their cell surface, show increased levels of activated Erk1/2 and of JunB; participating JunB in the proliferative capacity of these lymphomas. Here, we show that ALCL lymphoma cells also present high expression levels of the proto-oncogenic Cot (MAP3K8). Using pharmacological drugs as well as the RNA interference technique we show that Cot protein is responsible for the constitutive Erk1/2 activation in the ALCL lymphoma cells, SUDHL-1. Besides, inhibition of Cot activity reduces the number of cell divisions which is achieved, at least in part, by the control that Cot exercises on the activation state of p70 S6K and on the expression levels of JunB. Since Cot represents an alternative mode, independently of RAF, to activate Erk1/2, all these data strongly suggest that molecular targeting of Cot may be a potential new specific strategy for ALCL lymphomas therapy, without the fully disturbance of the Erk1/2 function.

Fernandez, Margarita, E-mail: mfernandez@iib.uam.es [Instituto de Investigaciones Biomedicas 'Alberto Sols', CSIC-UAM, Madrid and Departamento de Bioquimica, Facultad de Medicina de la Universidad Autonoma de Madrid (Spain)] [Instituto de Investigaciones Biomedicas 'Alberto Sols', CSIC-UAM, Madrid and Departamento de Bioquimica, Facultad de Medicina de la Universidad Autonoma de Madrid (Spain); Manso, Rebeca; Bernaldez, Flavia; Lopez, Pilar; Martin-Duce, Antonio; Alemany, Susana [Instituto de Investigaciones Biomedicas 'Alberto Sols', CSIC-UAM, Madrid and Departamento de Bioquimica, Facultad de Medicina de la Universidad Autonoma de Madrid (Spain)] [Instituto de Investigaciones Biomedicas 'Alberto Sols', CSIC-UAM, Madrid and Departamento de Bioquimica, Facultad de Medicina de la Universidad Autonoma de Madrid (Spain)

2011-08-12

200

Activation of legumain involves proteolytic and conformational events, resulting in a context- and substrate-dependent activity profile  

PubMed Central

Localized mainly to endo/lysosomes, legumain plays an important role in exogenous antigen processing and presentation. The cysteine protease legumain, also known as asparaginyl endopepetidase AEP, is synthesized as a zymogen and is known to undergo pH-dependent autoproteolytic activation whereby N-terminal and C-terminal propeptides are released. However, important mechanistic details of this pH-dependent activation as well as the characteristic pH activity profile remain unclear. Here, it is shown that all but one of the autocatalytic cleavage events occur in trans, with only the release of the C-terminal propeptide being relevant to enzymatic activity. An intriguing super-activation event that appears to be exclusively conformational in nature and enhances the enzymatic activity of proteolytically fully processed legumain by about twofold was also found. Accepting asparagines and, to lesser extent, aspartic acid in P1, super-activated legumain exhibits a marked pH dependence that is governed by the P1 residue of its substrate and conformationally stabilizing factors such as temperature or ligands. The crystallization and preliminary diffraction data analysis of active legumain are presented, which form an important basis for further studies that should clarify fundamental aspects of activation, activity and inactivation of legumain, which is a key target in (auto-)immunity and cancer.

Dall, Elfriede; Brandstetter, Hans

2012-01-01

201

Control of 5-aminolaevulinate synthetase activity in Rhodopseudomonas spheroides. The involvement of sulphur metabolism  

PubMed Central

1. The `initial' 5-aminolaevulinate synthetase activity, that is the activity observed immediately after cell disruption, in extracts prepared from unharvested semianaerobically grown Rhodopseudomonas spheroides, was twice that observed under the same assay conditions in extracts prepared from harvested cells. 2. The effect of oxygenation of a culture on the `maximum' aminolaevulinate synthetase activity, that is the activity observed 1h after disruption of harvested cells, is markedly influenced by the contents of the growth medium. Oxygenation of organisms for 1h in the medium in which they have grown produces an 80–90% decrease in maximum activity, whereas similar treatment of organisms resuspended in fresh medium produces less than a 40% decrease. 3. This protective effect of fresh medium is absolutely dependent on the presence of sulphate. When cells are suspended in sulphate-deficient fresh medium, the maximum activity falls by 65–75% even without oxygenation. A high maximum activity is regenerated when sulphate is resupplied. 4. When organisms are oxygenated in the medium in which they have grown, the cellular contents of GSH+GSSG and cysteine+cystine fall very markedly and homolanthionine is formed. Both the fall in aminolaevulinate synthetase activity and the changes in sulphur metabolism are largely prevented by the addition of compounds which stimulate synthesis of cysteine de novo or inhibit the conversion of cysteine S into homocysteine S. 5. The maximum aminolaevulinate synthetase activity was directly proportional to the GSH+GSSG content of all cell preparations. In glutathione-depleted extracts the `low'-activity enzyme could be re-activated in vitro by the addition of GSH, GSSG, cysteine or cystine, whereas in extracts with a high glutathione content the `high'-activity enzyme was unaffected by these sulphur compounds. 6. The activation of low-activity enzyme with exogenous sulphur compounds was prevented by excluding air or by adding NADH. Studies with purified enzyme indicate that sulphur compounds do not interact directly with the enzyme, but that their effect is mediated by a number of other endogenous factors.

Neuberger, Albert; Sandy, John D.; Tait, George H.

1973-01-01

202

Interrogating signaling nodes involved in cellular transformations using kinase activity probes  

PubMed Central

Summary Protein kinases catalyze protein phosphorylation and thereby control the flow of information through signaling cascades. Currently available methods for concomitant assessment of the enzymatic activities of multiple kinases in complex biological samples rely upon indirect proxies for enzymatic activity, such as posttranslational modifications to protein kinases. Our laboratories have recently described a method for directly quantifying the enzymatic activity of kinases in unfractionated cell lysates using substrates containing a phosphorylation-sensitive unnatural amino acid termed CSox, which can be monitored using fluorescence. Herein, we demonstrate the utility of this methodology using a probe set encompassing p38?, MK2, ERK1/2, Akt, and PKA. This panel of chemosensors provides activity measurements of individual kinases in a model of skeletal muscle differentiation and can be readily used to generate individualized kinase activity profiles for tissue samples from clinical cancer patients.

Stains, Cliff I.; Tedford, Nathan C.; Walkup, Traci C.; Lukovic, Elvedin; Goguen, Brenda N.; Griffith, Linda G.; Lauffenburger, Douglas A.; Imperiali, Barbara

2012-01-01

203

Inflammatory genes and neural activity: involvement of immune genes in synaptic function and behavior.  

PubMed

The function of pro-inflammatory cytokines and chemokines in brain injury and autoimmune diseases has been long recognized. There is however, a significant lack of information regarding the role of constitutively expressed immune genes in the normal brain. The current evidence points to the involvement of certain cytokines and major histocompatibility complex (MHC) molecules in synaptic function and plasticity. Furthermore, constitutively expressed chemokines in neurons provide an additional indication of a role for these molecules in neural function. In addition, clinical data suggests a dysregulation of immune genes in the cerebrospinal fluid of psychiatric patients who have neither brain injury nor autoimmune diseases. This review will discuss recent data indicating a role for immune genes in synaptic stability and will also discuss the implications for specific brain functions involving mood and cognition. PMID:15569608

Tonelli, Leonardo H; Postolache, Teodor T; Sternberg, Esther M

2005-01-01

204

Purinergic receptors are involved in tooth-pulp evoked nocifensive behavior and brainstem neuronal activity  

Microsoft Academic Search

BACKGROUND: To evaluate whether P2X receptors are involved in responses to noxious pulp stimulation, the P2X3 and P2X2\\/3 receptor agonist ?,?-methyleneATP (?,?-meATP) was applied to the molar tooth pulp and nocifensive behavior and extracellular-signal regulated kinase (ERK) phosphorylation in trigeminal spinal subnucleus caudalis (Vc), trigeminal spinal subnucleus interpolaris (Vi), upper cervical spinal cord (C1\\/C2) and paratrigeminal nucleus (Pa5) neurons were

Kazunori Adachi; Kohei Shimizu; James W Hu; Ikuko Suzuki; Hiroshi Sakagami; Noriaki Koshikawa; Barry J Sessle; Masamichi Shinoda; Makiko Miyamoto; Kuniya Honda; Koichi Iwata

2010-01-01

205

Involvement of lipid rafts in adhesion-induced activation of Met and EGFR  

PubMed Central

Background Cell adhesion has been shown to induce activation of certain growth factor receptors in a ligand-independent manner. However, the mechanism for such activation remains obscure. Methods Human epidermal carcinoma A431 cells were used as a model to examine the mechanism for adhesion-induced activation of hepatocyte growth factor receptor Met and epidermal growth factor receptor (EGFR). The cells were suspended and replated on culture dishes under various conditions. The phosphorylation of Met at Y1234/1235 and EGFR at Y1173 were used as indicators for their activation. The distribution of the receptors and lipid rafts on the plasma membrane were visualized by confocal fluorescent microscopy and total internal reflection microscopy. Results We demonstrate that Met and EGFR are constitutively activated in A431 cells, which confers proliferative and invasive potentials to the cells. The ligand-independent activation of Met and EGFR in A431 cells relies on cell adhesion to a substratum, but is independent of cell spreading, extracellular matrix proteins, and substratum stiffness. This adhesion-induced activation of Met and EGFR cannot be attributed to Src activation, production of reactive oxygen species, and the integrity of the cytoskeleton. In addition, we demonstrate that Met and EGFR are independently activated upon cell adhesion. However, partial depletion of Met and EGFR prevents their activation upon cell adhesion, suggesting that overexpression of the receptors is a prerequisite for their self-activation upon cell adhesion. Although Met and EGFR are largely distributed in 0.04% Triton-insoluble fractions (i.e. raft fraction), their activated forms are detected mainly in 0.04% Triton-soluble fractions (i.e. non-raft fraction). Upon cell adhesion, lipid rafts are accumulated at the cell surface close to the cell-substratum interface, while Met and EGFR are mostly excluded from the membrane enriched by lipid rafts. Conclusions Our results suggest for the first time that cell adhesion to a substratum may induce a polarized distribution of lipid rafts to the cell-substratum interface, which may allow Met and EGFR to be released from lipid rafts, thus leading to their activation in a ligand-independent manner.

2011-01-01

206

B cell activation involves nanoscale receptor reorganizations and inside-out signaling by Syk  

PubMed Central

Binding of antigen to the B cell antigen receptor (BCR) initiates a multitude of events resulting in B cell activation. How the BCR becomes signaling-competent upon antigen binding is still a matter of controversy. Using a high-resolution proximity ligation assay (PLA) to monitor the conformation of the BCR and its interactions with co-receptors at a 10–20 nm resolution, we provide direct evidence for the opening of BCR dimers during B cell activation. We also show that upon binding Syk opens the receptor by an inside-out signaling mechanism that amplifies BCR signaling. Furthermore, we found that on resting B cells, the coreceptor CD19 is in close proximity with the IgD-BCR and on activated B cells with the IgM-BCR, indicating nanoscale reorganization of receptor clusters during B cell activation. DOI: http://dx.doi.org/10.7554/eLife.02069.001

Klasener, Kathrin; Maity, Palash C; Hobeika, Elias; Yang, Jianying; Reth, Michael

2014-01-01

207

B cell activation involves nanoscale receptor reorganizations and inside-out signaling by Syk.  

PubMed

Binding of antigen to the B cell antigen receptor (BCR) initiates a multitude of events resulting in B cell activation. How the BCR becomes signaling-competent upon antigen binding is still a matter of controversy. Using a high-resolution proximity ligation assay (PLA) to monitor the conformation of the BCR and its interactions with co-receptors at a 10-20 nm resolution, we provide direct evidence for the opening of BCR dimers during B cell activation. We also show that upon binding Syk opens the receptor by an inside-out signaling mechanism that amplifies BCR signaling. Furthermore, we found that on resting B cells, the coreceptor CD19 is in close proximity with the IgD-BCR and on activated B cells with the IgM-BCR, indicating nanoscale reorganization of receptor clusters during B cell activation.DOI: http://dx.doi.org/10.7554/eLife.02069.001. PMID:24963139

Kläsener, Kathrin; Maity, Palash C; Hobeika, Elias; Yang, Jianying; Reth, Michael

2014-01-01

208

Mechanism of activation of methyltransferases involved in translation by the Trm112 'hub' protein  

PubMed Central

Methylation is a common modification encountered in DNA, RNA and proteins. It plays a central role in gene expression, protein function and mRNA translation. Prokaryotic and eukaryotic class I translation termination factors are methylated on the glutamine of the essential and universally conserved GGQ motif, in line with an important cellular role. In eukaryotes, this modification is performed by the Mtq2-Trm112 holoenzyme. Trm112 activates not only the Mtq2 catalytic subunit but also two other tRNA methyltransferases (Trm9 and Trm11). To understand the molecular mechanisms underlying methyltransferase activation by Trm112, we have determined the 3D structure of the Mtq2-Trm112 complex and mapped its active site. Using site-directed mutagenesis and in vivo functional experiments, we show that this structure can also serve as a model for the Trm9-Trm112 complex, supporting our hypothesis that Trm112 uses a common strategy to activate these three methyltransferases.

Liger, Dominique; Mora, Liliana; Lazar, Noureddine; Figaro, Sabine; Henri, Julien; Scrima, Nathalie; Buckingham, Richard H.; van Tilbeurgh, Herman; Heurgue-Hamard, Valerie; Graille, Marc

2011-01-01

209

ERK6, a Mitogen-Activated Protein Kinase Involved in C2C12 Myoblast Differentiation  

Microsoft Academic Search

ERK6, a mitogen-activated protein (MAP) kinase-related serine\\/threonine kinase, is highly expressed in human skeletal muscle and appears to function as a signal transducer during differentiation of myoblasts to myotubes. In transfected 293 cells, activation of the 45-kDa enzyme results in tyrosine-phosphorylated 46- and 56-kDa forms, which phosphorylate myelin basic protein. Overexpression of wild-type ERK6 or the inactive mutant Y185F has

Cornelia Lechner; Muayad A. Zahalka; Jean-Francois Giot; Niels Peter H. Moller; Axel Ullrich

1996-01-01

210

Anticancer activity of thymoquinone in breast cancer cells: possible involvement of PPAR-? pathway.  

PubMed

Thymoquinone (TQ), an active ingredient of Nigella sativa, has been reported to exhibit anti-oxidant, anti-inflammatory and anti-tumor activities through mechanism(s) that is not fully understood. In this study, we report the anticancer effects of TQ on breast cancer cells, and its potential effect on the PPAR-? activation pathway. We found that TQ exerted strong anti-proliferative effect in breast cancer cells and, when combined with doxorubicin and 5-fluorouracil, increased cytotoxicity. TQ was found to increase sub-G1 accumulation and annexin-V positive staining, indicating apoptotic induction. In addition, TQ activated caspases 8, 9 and 7 in a dose-dependent manner. Migration and invasive properties of MDA-MB-231 cells were also reduced in the presence of TQ. Interestingly, we report for the first time that TQ was able to increase PPAR-? activity and down-regulate the expression of the genes for Bcl-2, Bcl-xL and survivin in breast cancer cells. More importantly, the increase in PPAR-? activity was prevented in the presence of PPAR-? specific inhibitor and PPAR-? dominant negative plasmid, suggesting that TQ may act as a ligand of PPAR-?. Also, we observed using molecular docking analysis that TQ indeed formed interactions with 7 polar residues and 6 non-polar residues within the ligand-binding pocket of PPAR-? that are reported to be critical for its activity. Taken together, our novel observations suggest that TQ may have potential implication in breast cancer prevention and treatment, and show for the first time that the anti-tumor effect of TQ may also be mediated through modulation of the PPAR-? activation pathway. PMID:21679698

Woo, Chern Chiuh; Loo, Ser Yue; Gee, Veronica; Yap, Chun Wei; Sethi, Gautam; Kumar, Alan Prem; Tan, Kwong Huat Benny

2011-09-01

211

Activities of enzymes involved in starch synthesis in wheat grains differing in starch content  

Microsoft Academic Search

This work was carried out to characterize starch accumulation and activities of key enzymes during grain filling in two wheat\\u000a cultivars differing in starch content. The results showed that the starch accumulation rate (SAR) and activities of sucrose\\u000a synthase, ADP-glucose pyrophosphorylase, soluble starch synthase, granule-bound starch synthase, and starch branching enzyme\\u000a in the cultivar with a high starch content were

Zhongmin Dai

2010-01-01

212

Enzyme activities of marine bacteria involved in Laminaria thallus decomposition and the resulting sugar release  

Microsoft Academic Search

The extracellular decomposing enzyme activities of marine bacteria, including 60 and 16 strains of Laminaria-thallus decomposing bacteria (LDB) and non-LDB, respectively, were determined against several algal polysaccharides. A number of LDB decomposed alginate, fucoidan, and cellulose, but not laminarin. Clear decomposing activity was not observed in the culture supernatant from nutrient broth, but was detected in that from a Laminaria-thallus

M. Uchida

1995-01-01

213

Protease-Activated Receptor2 Involvement in Hypotension in Normal and Endotoxemic Rats In Vivo  

Microsoft Academic Search

Background—The protease-activated receptor-2 (PAR-2) is expressed by vascular endothelial cells and upregulated by lipopolysaccharide (LPS) in vitro. PAR-2 is activated by a tethered ligand created after proteolytic cleavage by trypsin or experimentally by a synthetic agonist peptide (PAR-2AP) corresponding to the new amino terminus of the tethered ligand. Methods and Results—Intravenous administration of PAR-2AP (0.1, 0.3, and 1 mg\\/kg) to

Carla Cicala; Aldo Pinto; Mariarosaria Bucci; Raffaella Sorrentino; Brian Walker; Patrick Harriot; Alan Cruchley; Supriya Kapas; Gareth L. Howells; Giuseppe Cirino

214

Involvement of Tissue Plasminogen Activator in Onset and Effector Phases of Experimental Allergic Encephalomyelitis  

PubMed Central

Inflammation, demyelination, and neurodegeneration are pathological features of multiple sclerosis (MS). In the brains of MS patients, tissue plasminogen activator (tPA) mRNA and protein are upregulated, and changes in the levels of tPA correlate with progression of the disease. However, the role of tPA in MS is as yet unknown. tPA functions in the CNS in neuronal plasticity and cell death. tPA also mediates the activation of microglia, the CNS “immune cells.” In this study, we establish that tPA activity increases during major oligodendrocyte glycoprotein-induced experimental allergic encephalomyelitis (EAE) in normal mice. To explore the role of tPA in this disease as a model for MS, we have examined the EAE course and expression of histopathological markers in mice lacking tPA (tPA ?/?). We find that tPA ?/? mice have a delayed onset of EAE but then exhibit increased severity and delayed recovery from the neurological dysfunction. Demyelination and axon degeneration are delayed, microglial activation is attenuated, and the production of chemokines is decreased. Our results suggest that tPA and activated microglia have complex roles in MS/EAE, and that these roles are harmful during the onset of the disease but beneficial in the recovery phase. A temporally restricted attenuation of tPA activity could have therapeutic potential in the management of MS.

Lu, Weiquan; Bhasin, Madhuri; Tsirka, Stella E.

2014-01-01

215

Involvement of Endoplasmic Reticulum Stress in Albuminuria Induced Inflammasome Activation in Renal Proximal Tubular Cells  

PubMed Central

Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA) could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E). Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA) which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria.

Fang, Li; Xie, Da; Wu, Xian; Cao, Hongdi; Su, Weifang; Yang, Junwei

2013-01-01

216

Involvement of endoplasmic reticulum stress in albuminuria induced inflammasome activation in renal proximal tubular cells.  

PubMed

Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA) could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E). Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA) which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria. PMID:23977286

Fang, Li; Xie, Da; Wu, Xian; Cao, Hongdi; Su, Weifang; Yang, Junwei

2013-01-01

217

NIK is involved in constitutive activation of the alternative NF-{kappa}B pathway and proliferation of pancreatic cancer cells  

SciTech Connect

Pancreatic cancer has one of the poorest prognoses among human neoplasms. Constitutive activation of NF-{kappa}B is frequently observed in pancreatic cancer cells and is involved in their malignancy. However, little is known about the molecular mechanism of this constitutive NF-{kappa}B activation. Here, we show that the alternative pathway is constitutively activated and NF-{kappa}B-inducing kinase (NIK), a mediator of the alternative pathway, is significantly expressed in pancreatic cancer cells. siRNA-mediated silencing of NIK expression followed by subcellular fractionation revealed that NIK is constitutively involved in the processing of p100 and nuclear transport of p52 and RelB in pancreatic cancer cells. In addition, NIK silencing significantly suppressed proliferation of pancreatic cancer cells. These results clearly indicate that NIK is involved in the constitutive activation of the alternative pathway and controls cell proliferation in pancreatic cancer cells. Therefore, NIK might be a novel target for the treatment of pancreatic cancer.

Nishina, Takashi [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)] [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Yamaguchi, Noritaka [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan) [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo 162-0041 (Japan); Gohda, Jin [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)] [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Semba, Kentaro [Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo 162-0041 (Japan) [Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo 162-0041 (Japan); Department of Life Science and Medical Bio-science, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 (Japan); Inoue, Jun-ichiro, E-mail: jun-i@ims.u-tokyo.ac.jp [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)] [Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)

2009-10-09

218

Phospholipase A{sub 2} is involved in the mechanism of activation of neutrophils by polychlorinated biphenyls  

SciTech Connect

Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), activates neutrophils to produce superoxide anion (O{sub 2}{sup {minus}}) by a mechanism that involves phospholipase C-dependent hydrolysis of membrane phosphoinositides; however, subsequent signal transduction mechanisms are unknown. This study determines whether phospholipase A{sub 2}-dependent release of arachidonic acid is involved in PCB-induced O{sub 2}{sup {minus}} production. O{sub 2}{sup {minus}} production was measured in vitro in glycogen-elicited, rat neutrophils in the presence and absence of the inhibitors of phospholipase A{sub 2}: quinacrine, 4-bromophenacyl bromide (BPB), and manoalide. All three agents significantly decreased the amount of O{sub 2}{sup {minus}} detected during stimulation of neutrophils with Aroclor 1242. Similar inhibition occurred when neutrophils were activated with the classical stimuli, formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol myristate acetate. The effects of BPB and manoalide were not a result of cytotoxicity or other nonspecific effects. Significant release of {sup 3}H-arachidonic acid preceded O{sub 2}{sup {minus}} production in neutrophils stimulated with Aroclor 1242 or fMLP. Manoalide, at a concentration that abolished O{sub 2}{sup {minus}} production, also inhibited the release of {sup 3}H-arachidonate. Aspirin, zileuton, or WEB 2086 did not affect Aroclor 1242-induced O{sub 2}{sup {minus}} production, suggesting that eicosanoids and platelet-activating factor are not needed for neutrophil activation by PCBs. Activation of phos-pholipase A{sub 2} and O{sub 2}{sup {minus}} production do not appear to involve the Ah receptor. These data suggest that Aroclor 1242 stimulates neutrophils to produce O{sub 2}{sup {minus}} by a mechanism that involves phospholipase A{sub 2}-dependent release of arachiodonic acid. 49 refs., 6 figs., 2 tabs.

Tithof, P.K.; Schiamberg, E.; Ganey, P.E. [Univ. of Michigan, Ann Arbor, MI (United States); Peters-Golden, M. [Michigan State Univ., East Lansing, MI (United States)

1996-01-01

219

Involvement of Protein Kinase C in Rickettsia rickettsii-Induced Transcriptional Activation of the Host Endothelial Cell  

PubMed Central

Our laboratory has reported on a biphasic pattern of nuclear factor ?B (NF-?B) activation in cultured human umbilical vein endothelial cells during infection with Rickettsia rickettsii, an obligate, intracellular bacterium, and the etiologic agent of Rocky Mountain spotted fever. Transcriptional activation of the tissue factor (TF) gene during this infection has been shown to involve NF-?B. To further understand the signal transduction events underlying these phenomena, we studied the role of protein kinase C (PKC), a ubiquitous family of phospholipid-dependent enzymes implicated in the regulation of a variety of cell signaling pathways. Two inhibitors of PKC, namely, bisindolylmaleimide I hydrochloride (BM-1) and calphostin C, which exhibit different inhibitory properties towards various isozymes of PKC, were used. Infection of cells with R. rickettsii in the presence of BM-1 (50 nM) did not significantly affect NF-?B, whereas calphostin C (2.5 ?M) completely blocked the early phase of NF-?B activation. The late, sustained phase also was not affected by treatment with BM-1. Downregulation of phorbol ester-sensitive PKCs by long-term treatment with phorbol 12-myristate 13-acetate (PMA) did not inhibit NF-?B activation. Likewise, this downregulation had no effect on induction of TF activity. The activity of TF was, however, sensitive to BM-1 and calphostin C, whereas expression of TF mRNA was inhibited only by calphostin C. Overall, these results suggest the lack of involvement of classical PKC pathways in R. rickettsii-induced NF-?B activation but the possible involvement of a non-PMA-responsive PKC isoform in the posttranscriptional control of TF expression.

Sahni, Sanjeev K.; Turpin, Loel C.; Brown, Tracy L.; Sporn, Lee Ann

1999-01-01

220

A mechanistic study of the proapoptotic effect of tolfenamic acid: involvement of NF-?B activation.  

PubMed

Recent studies demonstrate that tolfenamic acid (TA) induces apoptosis and suppresses the development and progression of several types of cancers. However, the underlying mechanisms are complex and remain to be fully elucidated. Nuclear factor-kappaB (NF-?B) plays a critical role in inflammation, cancer development and progression. Although non-steroidal anti-inflammatory drugs modulate NF-?B signaling pathway in different ways, the link between NF-?B and TA-induced apoptosis of colorectal cancer cells has yet to be thoroughly investigated. In this study, we examined the effects of TA on the NF-?B pathway and apoptosis. TA activated NF-?B transcriptional activity and binding affinity of NF-?B to DNA. TA-induced NF-?B activation was mediated by an increased phosphorylation and proteosomal degradation of I?B-? and subsequent p65 nuclear translocation. We also observed that TA stabilized p65 and increased nuclear accumulation via an increase of p65 phosphorylation at Ser276 residue, which was mediated by p38 mitogen-activated protein kinase and extracellular signal-regulated kinase. The knockout of p53 blocked TA-induced transcriptional activation of NF-?B, but not the p65 nuclear accumulation. TA increased transcriptional activity of p53 and the binding affinity of p53 with p65, which are mediated by p38 mitogen-activated protein kinase and extracellular signal-regulated kinase-stimulated Ser276 phosphorylation. TA-induced apoptosis was ameliorated by the knockout of p65 and p53 and the point mutation of p65 at Ser276 residue. We demonstrate a novel molecular mechanism by which TA induced the NF-?B and apoptosis in human colorectal cancer cells. PMID:23784084

Jeong, Jin Boo; Yang, Xuyu; Clark, Ruth; Choi, Jieun; Baek, Seung Joon; Lee, Seong-Ho

2013-10-01

221

Identification of MAPKs and their possible MAPK kinase activators involved in the Pto-mediated defense response of tomato.  

PubMed

The Pto kinase mediates resistance to bacterial speck disease in tomato by activating host defenses upon recognition of Pseudomonas syringae pv. tomato strains expressing the AvrPto or AvrPtoB proteins. Previous gene-silencing experiments have indicated that mitogen activated protein kinase (MAPK) cascades play a key role downstream of the Pto kinase to activate host defense responses. Here we use biochemical methods to demonstrate that two tomato MAPKs, LeMPK2 and LeMPK3, are activated in leaves in a Pto-specific manner upon expression of AvrPto and AvrPtoB. We show that these same MAPKs are activated upon overexpression of LeMAPKKKalpha, a protein previously demonstrated to be involved in Pto-mediated immunity. We identified two phylogenetically unrelated MAPK kinases (LeMKK2 and LeMKK4) that when overexpressed in leaves elicit cell death and activate LeMPK2 and LeMPK3. In vitro analysis demonstrated that LeMKK2 and LeMKK4 each phosphorylate the same subset of three MAPKs. Together these data provide biochemical evidence for the involvement of MAPK cascades in Pto-mediated resistance. PMID:15371431

Pedley, Kerry F; Martin, Gregory B

2004-11-19

222

The relationship between active ghrelin levels and human obesity involves alterations in resting energy expenditure.  

PubMed

Ghrelin is a gastric hormone that exerts a stimulatory effect on appetite and fat accumulation. Ser(3) octanoylation is regarded as a prerequisite for ghrelin biological activity, although des-octanoylated forms may retain biological functions in vitro. Circulating ghrelin levels are usually low in obesity and in states of positive energy balance. Hence, the aim of our study was to analyze plasma active and serum total ghrelin levels in 20 obese (ages, 22-42 yr; body mass index, 41.3 +/- 1.1 kg/m(2)) and 20 lean subjects (ages, 22-43 yr; body mass index, 22.4 +/- 0.6 kg/m(2)) as well as their relationship to measures of glucose homeostasis, body fat, and resting energy expenditure (REE). The measured/predicted REE percentage ratio was calculated to subdivide groups into those with positive (> or = 100% ) and negative (<100%) ratio values. In obese patients, plasma active (180 +/- 18 vs. 411 +/- 57 pg/ml; P < 0.001) and serum total ghrelin levels (3650 +/- 408 vs. 5263 +/- 643 pg/ml; P < 0.05) were significantly lower when compared with lean subjects. Hence, ghrelin activity, defined as the proportion of active over total ghrelin levels, was similarly reduced in the obese state (6.1 +/- 0.9% vs. 8.4 +/- 1%; P < 0.05). There was a significant correlation between active and total ghrelin (r = 0.62; P < 0.001), and between total ghrelin and insulin (r = -0.53; P < 0.001) or insulin resistance using the homeostatis model of assessment-insulin resistance (r = -0.49; P < 0.001) approach. Significantly higher active ghrelin levels (214 +/- 22 vs. 159 +/- 30 pg/ml; P < 0.05) and ghrelin activity (8 +/- 1.7% vs. 4.9 +/- 0.9%; P < 0.05) were observed in patients with positive compared with negative measured/predicted REE ratio values. Our study shows that obesity is associated with an impairment of the entire ghrelin system. The observation that ghrelin is further decreased in cases of abnormal energy profit adds new evidence to the relationship between ghrelin activity and energy balance in obesity. PMID:14764817

Marzullo, Paolo; Verti, Barbara; Savia, Giulio; Walker, Gillian E; Guzzaloni, Gabriele; Tagliaferri, Mariantonella; Di Blasio, Annamaria; Liuzzi, Antonio

2004-02-01

223

Involvement of human internal globus pallidus in the early modulation of cortical error-related activity.  

PubMed

The detection and assessment of errors are a prerequisite to adapt behavior and improve future performance. Error monitoring is afforded by the interplay between cortical and subcortical neural systems. Ample evidence has pointed to a specific cortical error-related evoked potential, the error-related negativity (ERN), during the detection and evaluation of response errors. Recent models of reinforcement learning implicate the basal ganglia (BG) in early error detection following the learning of stimulus-response associations and in the modulation of the cortical ERN. To investigate the influence of the human BG motor output activity on the cortical ERN during response errors, we recorded local field potentials from the sensorimotor area of the internal globus pallidus and scalp electroencephalogram representing activity from the posterior medial frontal cortex in patients with idiopathic dystonia (hands not affected) during a flanker task. In error trials, a specific pallidal error-related potential arose 60 ms prior to the cortical ERN. The error-related changes in pallidal activity-characterized by theta oscillations-were predictive of the cortical error-related activity as assessed by Granger causality analysis. Our findings show an early modulation of error-related activity in the human pallidum, suggesting that pallidal output influences the cortex at an early stage of error detection. PMID:23349222

Herrojo Ruiz, María; Huebl, Julius; Schönecker, Thomas; Kupsch, Andreas; Yarrow, Kielan; Krauss, Joachim K; Schneider, Gerd-Helge; Kühn, Andrea A

2014-06-01

224

Spinal Astrocytic Activation Is Involved in a Virally-Induced Rat Model of Neuropathic Pain  

PubMed Central

Postherpetic neuralgia (PHN), the most common complication of herpes zoster (HZ), plays a major role in decreased life quality of HZ patients. However, the neural mechanisms underlying PHN remain unclear. Here, using a PHN rat model at 2 weeks after varicella zoster virus infection, we found that spinal astrocytes were dramatically activated. The mechanical allodynia and spinal central sensitization were significantly attenuated by intrathecally injected L-?-aminoadipate (astrocytic specific inhibitor) whereas minocycline (microglial specific inhibitor) had no effect, which indicated that spinal astrocyte but not microglia contributed to the chronic pain in PHN rat. Further study was taken to investigate the molecular mechanism of astrocyte-incudced allodynia in PHN rat at post-infection 2 weeks. Results showed that nitric oxide (NO) produced by inducible nitric oxide synthase mediated the development of spinal astrocytic activation, and activated astrocytes dramatically increased interleukin-1? expression which induced N-methyl-D-aspartic acid receptor (NMDAR) phosphorylation in spinal dorsal horn neurons to strengthen pain transmission. Taken together, these results suggest that spinal activated astrocytes may be one of the most important factors in the pathophysiology of PHN and “NO-Astrocyte-Cytokine-NMDAR-Neuron” pathway may be the detailed neural mechanisms underlying PHN. Thus, inhibiting spinal astrocytic activation may represent a novel therapeutic strategy for clinical management of PHN.

Tang, Yu; Zhang, Xu-Dong; Ren, Peng-Cheng; Gao, Chang-Jun; Sun, Xu-De; Xu, Li-Xian

2011-01-01

225

Phosphatidylcholine-derived phosphatidic acid and diacylglycerol are involved in the signaling pathways activated by docetaxel.  

PubMed

Taxanes are known to activate several cellular signals including mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-kappa B), tyrosine phosphorylation of Shc, and serine phosphorylation of Bcl-2. However, the mediators of these signaling pathways are unknown. Using U937 leukemic cells, we evaluated the effect of docetaxel on phosphatidylcholine (PC) and its metabolites, phosphatidic acid (PA) and diacylglycerol (DAG), and their impact on MAPK and NF-kappa B activation, as well as on Raf-1 and Bcl-2 phosphorylation. Metabolic labeling studies showed that docetaxel (10 nM) induced two waves of PA production (130-140%), which were detected at 1 and 10 min. Docetaxel also stimulated DAG production (130%), which followed the first PA wave. The initial PA burst was due to phospholipase D (PLD)-mediated PC hydrolysis. Subsequent DAG production was inhibited by the phosphatidate phosphohydrolase (PAP) inhibitor, propranolol. R59949, a DAG kinase inhibitor, increased DAG accumulation and blocked the second PA wave. These results suggest that docetaxel triggers a metabolic cascade consisting in PLD-mediated PC hydrolysis, PA release, PAP-dependent DAG production, and DAG kinase stimulation, leading to DAG conversion back to PA. Neither R59949 nor propranolol influenced docetaxel-induced Raf-1/ERK activation. However, R59949 abrogated both NF-kappa B activation and Bcl-2 phosphorylation, suggesting that DAG and/or DAG-derived PA contribute in regulating these events. PMID:12724857

Maestre, Nicolas; Bezombes, Christine; Plo, Isabelle; Levade, Thierry; Lavelle, François; Laurent, Guy; Jaffrézou, Jean-Pierre

2003-01-01

226

Involvement of dopaminergic neuronal cystatin C in neuronal injury-induced microglial activation and neurotoxicity.  

PubMed

Factors released from injured dopaminergic (DA) neurons may trigger microglial activation and set in motion a vicious cycle of neuronal injury and inflammation that fuels progressive DA neurodegeneration in Parkinson's disease. In this study, using proteomic and immunoblotting analysis, we detected elevated levels of cystatin C in conditioned media (CM) from 1-methyl-4-phenylpyridinium and dieldrin-injured rat DA neuronal cells. Immunodepletion of cystatin C significantly reduced the ability of DA neuronal CM to induce activation of rat microglial cells as determined by up-regulation of inducible nitric oxide synthase, production of free radicals and release of proinflammatory cytokines as well as activated microglia-mediated DA neurotoxicity. Treatment of the cystatin C-containing CM with enzymes that remove O- and sialic acid-, but not N-linked carbohydrate moieties markedly reduced the ability of the DA neuronal CM to activate microglia. Taken together, these results suggest that DA neuronal cystatin C plays a role in the neuronal injury-induced microglial activation and neurotoxicity. These findings from the rat DA neuron-microglia in vitro model may help guide continued investigation to define the precise role of cystatin C in the complex interplay among neurons and glia in the pathogenesis of Parkinson's disease. PMID:22679891

Dutta, Garima; Barber, David S; Zhang, Ping; Doperalski, Nicholas J; Liu, Bin

2012-08-01

227

Activity involvement as an ecological asset: profiles of participation and youth outcomes.  

PubMed

Prior research has demonstrated that participation in out-of-school time activities is associated with positive and healthy development among adolescents. However, fewer studies have examined how trajectories of participation across multiple activities can impact developmental outcomes. Using data from Wave 3 (approximately Grade 7) through Wave 8 (approximately Grade 12) of the 4-H Study of Positive Youth Development, this study examined patterns of breadth in out-of-school time participation in activities and associated outcomes in positive youth development (PYD), Contribution to self and community, risk behaviors, and depressive symptoms. We assessed 927 students (on average across waves, 65.4% female) from a relatively racially and ethnically homogeneous sample (about 74% European American, across waves) with a mean age in Wave 3 of 12.98 years (SD = 0.52). The results indicated that high likelihood of participation in activities was consistently associated with fewer negative outcomes and higher scores on PYD and Contribution, as compared to low likelihood of participation in activities. Changes in the breadth of participation (in particular, moving from a high to a low likelihood of participation) were associated with increased substance use, depressive symptoms, and risk behaviors. Limitations of the current study, implications for future research, and applications to youth programs are discussed. PMID:24510166

Agans, Jennifer P; Champine, Robey B; DeSouza, Lisette M; Mueller, Megan Kiely; Johnson, Sara Kassie; Lerner, Richard M

2014-06-01

228

Evidence of active transport involvement in morphine transport via MDCKII and MDCK-PGP cell lines  

PubMed Central

Several transporters appear to be important in transporting various drugs. Many patients, who receive morphine as analgesic medication, also receive other medications with potency of changing morphine transport by affecting P-glycoprotein (P-GP) and oatp2 transport system. This could influence morphine pharmacokinetics and pharmacodynamics. The aim of present study was to elucidate the transport mechanisms involved in transporting morphine via MDCKII and MDCK-PGP cells. Morphine permeability was examined in the presence of various compounds with ability in inhibiting different transport systems including: digoxin, probenecid and d- glucose. The effect of morphine concentration changes on its transport was also examined. Morphine concentration was measured using HPLC with electrochemical detector. Morphine permeability via a MDCK II cells was greater than sucrose permeability, and reduced when a P-GP expressed cell line was used. Its permeability was increased significantly in the presence of a strong P-GP inhibitor. Morphine permeability decreased significantly in the presence of digoxin but not in the presence of d-glucose or probenecid. These results showed that morphine was a P-GP substrate, and digoxin related transporters such as oatp2 were involved in its transport. Morphine was not substrate for glucose or probenecid-sensitive transporters.

Mashayekhi, S.O.; Sattari, M.R.; Routledge, P.A.

2010-01-01

229

ERK6, a mitogen-activated protein kinase involved in C2C12 myoblast differentiation.  

PubMed

ERK6, a mitogen-activated protein (MAP) kinase-related serine/threonine kinase, is highly expressed in human skeletal muscle and appears to function as a signal transducer during differentiation of myoblasts to myotubes. In transfected 293 cells, activation of the 45-kDa enzyme results in tyrosine-phosphorylated 46- and 56-kDa forms, which phosphorylate myelin basic protein. Overexpression of wild-type ERK6 or the inactive mutant Y185F has no effect on fibroblast and myoblast proliferation, but it enhances or inhibits C2C12 cell differentiation to myotubes, respectively. Our findings suggest ERK6 to be a tissue-specific, differentiation signal-transducing factor that is connected to phosphotyrosine-mediated signaling pathways distinct from those activating other members of the MAP kinase family such as LRK1 and ERK2. PMID:8633070

Lechner, C; Zahalka, M A; Giot, J F; Møller, N P; Ullrich, A

1996-04-30

230

Blue light irradiation affects anthocyanin content and enzyme activities involved in postharvest strawberry fruit.  

PubMed

Blue light irradiation was applied to postharvest strawberry fruit to explore its influence on anthocyanin content and anthocyanin biosynthetic enzyme activities. Strawberry fruit was irradiated with blue light at 40 ?mol m(-2) s(-1) for 12 days at 5 °C. The results indicated that blue light treatment improved total anthocyanin content in strawberry fruit during storage. Meanwhile, the treatment increased the activities of glucose-6-phosphate, shikimate dehydrogenase, tyrosine ammonia-lyase, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate/coenzyme A ligase, dihydroflavonol-4-reductase, chalcone synthase, flavanone-3-?-hydroxylase, anthocyanin synthase, and UDP-glycose flavonoid-3-O-glycosyltranferase, which suggested that the enhancement of anthocyanin concentration by blue light might result from the activation of its related enzymes. Blue light might be proposed as a supplemental light source in the storage of strawberry fruit to improve its anthocyanin content. PMID:24783962

Xu, Feng; Cao, Shifeng; Shi, Liyu; Chen, Wei; Su, Xinguo; Yang, Zhenfeng

2014-05-21

231

Predominant involvement of CD8+CD28- lymphocytes in human immunodeficiency virus-specific cytotoxic activity.  

PubMed Central

Distinct functional CD8+ T-cell populations have been observed during human immunodeficiency virus (HIV) infection. One of these functions is the inhibition of viral replication by a noncytotoxic mechanism, which was shown to be mediated by the CD8+CD28+ subpopulation. On the other hand, CD8+ T cells exert an HIV-specific cytotoxic activity. The present study shows that CD8+CD28- lymphocytes display this HIV-specific cytotoxic activity, which is detectable immediately after the cells are purified from peripheral blood. The CD28- population is also able to proliferate and to retain its cytotoxic activity after in vitro restimulation with autologous blast cells. Finally, HIV-specific cytotoxic T cells can be obtained in vitro from the CD8+CD28+ population.

Fiorentino, S; Dalod, M; Olive, D; Guillet, J G; Gomard, E

1996-01-01

232

Involvement of Activating NK Cell Receptors and Their Modulation in Pathogen Immunity  

PubMed Central

Natural Killer (NK) cells are endowed with cell-structure-sensing receptors providing inhibitory protection from self-destruction (inhibitory NK receptors, iNKRs, including killer inhibitory receptors and other molecules) and rapid triggering potential leading to functional cell activation by Toll-like receptors (TLRs), cytokine receptors, and activating NK cell receptors including natural cytotoxicity receptors (NCRs, i.e., NKp46, NKp46, and NKp44). NCR and NKG2D recognize ligands on infected cells which may be endogenous or may directly bind to some structures derived from invading pathogens. In this paper, we address the known direct or indirect interactions between activating receptors and pathogens and their expression during chronic HIV and HCV infections.

Marras, Francesco; Bozzano, Federica; De Maria, Andrea

2011-01-01

233

Possible pathogenetic role of activated platelets in the primary antiphospholipid syndrome involving the central nervous system.  

PubMed

Neurological disorders occurring in the primary antiphospholipid syndrome (neuro-PAPS) have not yet been completely understood. Platelet activation has been suggested to play a crucial role in the pathogenesis of hemostatic disorders in the antiphospholipid syndrome, but no association with neuro-PAPS has been investigated so far. Therefore, we investigated 16 patients with PAPS by flow cytometry in the presence of circulating activated platelets as defined by the surface expression of activation-dependent glycoprotein CD62. In addition, the relationship among activated platelets and anticardiolipin antibodies (aCL) was evaluated. Compared to normal subjects CD62 was found significantly increased in these patients. Furthermore, a significantly increased percentage of CD62-positive platelets was found in the neuro-PAPS group (nine patients) compared to the non-neuro-PAPS patients (seven subjects). On the contrary, no significant difference was found between the two groups with regard to aCL IgG and platelet number. Furthermore, within the neuro-PAPS group, no difference was evidenced, in the CD62-positive platelet percentage, between the four subjects with thrombocytopenia and the five with the normal blood platelet count. Similarly, neuro-PAPS subjects with previous peripheral arterial and/or venous thrombosis did not show a significantly more elevated level of CD62-positive platelets. Finally, a linear correlation was found between the aCL IgG level and the CD62-positive platelet percentage in all the patients and, more significantly, in the neuro-PAPS group, but not within the non-neuro-PAPS patients. Our data demonstrate that circulating activated platelets are detectable by flow cytometry in the majority of PAPS patients and suggest the existence of a relationship among activated platelets, aCL, and neurological disease that patients affected by PAPS might undergo. PMID:9292045

Emmi, L; Bergamini, C; Spinelli, A; Liotta, F; Marchione, T; Caldini, A; Fanelli, A; De Cristofaro, M T; Dal Pozzo, G

1997-08-14

234

Peripheral neuropathy in the Twitcher mouse involves the activation of axonal caspase 3.  

PubMed

Infantile Krabbe disease results in the accumulation of lipid-raft-associated galactosylsphingosine (psychosine), demyelination, neurodegeneration and premature death. Recently, axonopathy has been depicted as a contributing factor in the progression of neurodegeneration in the Twitcher mouse, a bona fide mouse model of Krabbe disease. Analysis of the temporal-expression profile of MBP (myelin basic protein) isoforms showed unexpected increases of the 14, 17 and 18.5 kDa isoforms in the sciatic nerve of 1-week-old Twitcher mice, suggesting an abnormal regulation of the myelination process during early postnatal life in this mutant. Our studies showed an elevated activation of the pro-apoptotic protease caspase 3 in sciatic nerves of 15- and 30-day-old Twitcher mice, in parallel with increasing demyelination. Interestingly, while active caspase 3 was clearly contained in peripheral axons at all ages, we found no evidence of caspase accumulation in the soma of corresponding mutant spinal cord motor neurons. Furthermore, active caspase 3 was found not only in unmyelinated axons, but also in myelinated axons of the mutant sciatic nerve. These results suggest that axonal caspase activation occurs before demyelination and following a dying-back pattern. Finally, we showed that psychosine was sufficient to activate caspase 3 in motor neuronal cells in vitro in the absence of myelinating glia. Taken together, these findings indicate that degenerating mechanisms actively and specifically mediate axonal dysfunction in Krabbe disease and support the idea that psychosine is a pathogenic sphingolipid sufficient to cause axonal defects independently of demyelination. PMID:21929508

Smith, Benjamin; Galbiati, Francesca; Castelvetri, Ludovico Cantuti; Givogri, Maria I; Lopez-Rosas, Aurora; Bongarzone, Ernesto R

2011-01-01

235

Altered Renal FGF23-Mediated Activity Involving MAPK and Wnt: Effects of the Hyp Mutation  

PubMed Central

Fibroblast growth factor-23 (FGF23), a hormone central to renal phosphate handling, is elevated in multiple hypophosphatemic disorders. Initial FGF23-dependent Erk1/2 activity in the kidney localizes to the distal convoluted tubule (DCT) with the co-receptor ?-Klotho (KL), distinct from Npt2a in proximal tubules (PT). The Hyp mouse model of XLH is characterized by hypophosphatemia with increased Fgf23, and patients with XLH elevate FGF23 following combination therapy of phosphate and calcitriol. The molecular signaling underlying renal FGF23 activity, and whether these pathways are altered in hypophosphatemic disorders, is unknown. To examine Npt2a in vivo, mice were injected with FGF23. Initial p-Erk1/2 activity in the DCT occurred within 10 min, however Npt2a protein was latently reduced in the PT at 30–60 min, and was independent of Npt2a mRNA changes. KL-null mice had no DCT p-Erk1/2 staining following FGF23 delivery. Under basal conditions in Hyp mice, c-Fos and Egr1, markers of renal Fgf23 activity, were increased, however KL mRNA was reduced 60% (P<0.05). Despite the prevailing hypophosphatemia and elevated Fgf23, FGF23 injections into Hyp mice activated p-Erk1/2 in the DCT. FGF23 injection also resulted in phospho-?-catenin (p-?-cat) co-localization with KL in WT mice, and Hyp demonstrated strong p-?-cat staining under basal conditions, indicating potential cross-talk between Mapk and Wnt signaling. Collectively, these studies refine the mechanisms for FGF23 bioactivity, and demonstrate novel suppression of Wnt signaling in a KL-dependent DCT-PT axis, which is likely altered in XLH. Finally, the current treatment of phosphate and calcitriol for hypophosphatemic disorders may increase FGF23 activity.

Farrow, Emily G.; Summers, Lelia J.; Schiavi, Susan C.; McCormick, James A.; Ellison, David H.; White, Kenneth E.

2011-01-01

236

Involvement of absent in melanoma 2 in inflammasome activation in macrophages infected with Listeria monocytogenes.  

PubMed

Listeria monocytogenes invades the cytoplasm of macrophages and induces the activation of caspase-1 and the subsequent maturation of IL-1beta and IL-18. Although apoptosis-associated speck-like protein containing a caspase-activating and recruitment domain (ASC), an adaptor protein of nucleotide-binding oligomerization domain (Nod)-like receptors, has been shown to play an essential role in inducing this cellular response to L. monocytogenes, the mechanism has not been fully elucidated. In this study, we demonstrate the role of absent in melanoma 2 (AIM2), a recently described receptor of cytosolic DNA, in the activation of caspase-1 upon infection with L. monocytogenes. Secretion of IL-1beta and IL-18 from Nod-like receptor family, pyrin domain containing 3 (NLRP3) and Nod-like receptor family, caspase-activating and recruitment domain containing 4 (NLRC4) knockout macrophages in response to L. monocytogenes was only slightly decreased compared with the levels secreted from wild-type macrophages, whereas secretion from ASC knockout macrophages was completely impaired, suggesting that receptors other than NLRP3 and NLRC4 also take part in inflammasome activation in an ASC-dependent manner. To identify such receptors, the abilities of several receptor candidates (NLRP2, NLRP6, NLRP12, and AIM2) to induce the secretion of IL-1beta in response to L. monocytogenes were compared using the inflammasome system reconstructed in HEK293 cells. Among these receptor candidates, AIM2 conferred the highest responsiveness to the bacterium on HEK293 cells. Knockdown of AIM2 significantly decreased the secretion of IL-1beta and IL-18 from L. monocytogenes-infected macrophages. These results suggest that AIM2, in cooperation with NLRP3 and NLRC4, plays an important role in the activation of caspase-1 during L. monocytogenes infection. PMID:20566831

Tsuchiya, Kohsuke; Hara, Hideki; Kawamura, Ikuo; Nomura, Takamasa; Yamamoto, Takeshi; Daim, Sylvia; Dewamitta, Sita R; Shen, Yanna; Fang, Rendong; Mitsuyama, Masao

2010-07-15

237

Tumor cell alpha-N-acetylgalactosaminidase activity and its involvement in GcMAF-related macrophage activation.  

PubMed

Alpha-N-acetyl galactosaminidase (alpha-NaGalase) has been reported to accumulate in serum of cancer patients and be responsible for deglycosylation of Gc protein, which is a precursor of GcMAF-mediated macrophage activation cascade, finally leading to immunosuppression in advanced cancer patients. We studied the biochemical characterization of alpha-NaGalase from several human tumor cell lines. We also examined its effect on the potency of GcMAF to activate mouse peritoneal macrophage to produce superoxide in GcMAF-mediated macrophage activation cascade. The specific activity of alpha-NaGalases from human colon tumor cell line HCT116, human hepatoma cell line HepG2, and normal human liver cells (Chang liver cell line) were evaluated using two types of substrates; GalNAc-alpha-PNP (exo-type substrate) and Gal-beta-GalNAc-alpha-PNP (endo-type substrate). Tumor-derived alpha-NaGalase having higher activity than normal alpha-NaGalase, had higher substrate specificity to the exo-type substrate than to the endo-type substrate, and still maintained its activity at pH 7. GcMAF enhance superoxide production in mouse macrophage, and pre-treatment of GcMAF with tumor cell lysate reduce the activity. We conclude that tumor-derived alpha-NaGalase is different in biochemical characterization compared to normal alpha-NaGalase from normal Chang liver cells. In addition, tumor cell-derived alpha-NaGalase decreases the potency of GcMAF on macrophage activation. PMID:12062184

Mohamad, Saharuddin B; Nagasawa, Hideko; Uto, Yoshihiro; Hori, Hitoshi

2002-05-01

238

Sodium tungstate activates glycogen synthesis through a non-canonical mechanism involving G-proteins.  

PubMed

Tungstate treatment ameliorates experimental diabetes by increasing liver glycogen deposition through an as yet unidentified mechanism. The signalling mechanism of tungstate was studied in CHOIR cells and primary cultured hepatocytes. This compound exerted its pro-glycogenic effects through a new G-protein-dependent and Tyr-Kinase Receptor-independent mechanism. Chemical or genetic disruption of G-protein signalling prevented the activation of the Ras/ERK cascade and the downstream induction of glycogen synthesis caused by tungstate. Thus, these findings unveil a novel non-canonical signalling pathway that leads to the activation of glycogen synthesis and that could be exploited as an approach to treat diabetes. PMID:23260418

Zafra, Delia; Nocito, Laura; Domínguez, Jorge; Guinovart, Joan J

2013-01-31

239

Facilitation handlings induce increase in electromyographic activity of muscles involved in head control of Cerebral Palsy children.  

PubMed

This study aimed to investigate the electromyographic (EMG) activation of the main cervical muscles involved in the head control during two postures widely used for the facilitation of head control in children with Cerebral Palsy (CP). A crossover trial involving 31 children with clinical diagnosis of CP and spastic quadriplegia was conducted. Electromyography was used to measure muscular activity in randomized postures. Three positions were at rest: (a) lateral decubitus, (b) ventral decubitus on the floor and (c) ventral decubitus on the wedge. Handlings for facilitating the head control were performed using the hip joint as key point of control in two postures: (a) lateral decubitus and (b) ventral decubitus on wedge. All children underwent standardized handlings, performed by the same researcher with experience in the neurodevelopmental treatment. EMG signal was recorded from muscles involved in the head control (paraspinal and sternocleidomastoid muscles) in sagittal, frontal and transverse planes, at the fourth cervical vertebra (C4), tenth thoracic vertebra (T10) and sternocleidomastoid muscle (SCM) levels. The results showed a significant increase in muscle activation when handling was performed in the lateral decubitus at C4 (P<0.001), T10 (P<0.001) and SCM (P=0.02) levels. A significant higher muscle activation was observed when handling was performed in lateral decubitus when compared to ventral decubitus at C4 level (P<0.001). Handling in ventral decubitus also induced an increase in EMG activation at T10 (P=0.018) and SCM (P=0.004) levels but not at C4 level (P=0.38). In conclusion, handlings performed in both positions may induce the facilitation of head control, as evaluated by the activity of cervical and upper trunk muscles. Handling performed in lateral decubitus may induce a slightly better facilitation of head control. These findings contribute to evidence-based physiotherapy practice for the rehabilitation of severely spastic quadriplegic CP children. PMID:25010566

Simon, Anelise de Saldanha; Pinho, Alexandre Severo do; Grazziotin Dos Santos, Camila; Pagnussat, Aline de Souza

2014-10-01

240

Fungicidal Activity of Phosphinic Analogues of Amino Acids Involved in Methionine Metabolism  

Microsoft Academic Search

In medicine and agriculture, the necessity of rationally planning attempts to find for new biologically active chemical compounds because of a tendency towards a reduction in the rate of the introduction of new products [1]. The conventional approach, based on accidental discovery of new preparations with their subsequent chemical optimization, has proven to be inefficient. With respect to pesticides, it

Yu. N. Zhukov; N. A. Vavilova; T. I. Osipova; T. M. Voinova; E. N. Khurs; V. G. Dzhavakhia; R. M. Khomutov

2004-01-01

241

Regrouping: Organized Activity Involvement and Social Adjustment across the Transition to High School  

ERIC Educational Resources Information Center

Although organized activities (OAs) have been established as important contexts of development, limited work has examined the role of OAs across the high school transition in buffering adolescents' social adjustment by providing opportunities for visibility and peer affiliation. The transition to high school is characterized by numerous…

Bohnert, Amy M.; Aikins, Julie Wargo; Arola, Nicole T.

2013-01-01

242

Rap1 promotes VEGFR2 activation and angiogenesis by a mechanism involving integrin ?v?3  

PubMed Central

Vascular endothelial growth factor (VEGF) acting through VEGF receptor 2 (VEGFR2) on endothelial cells (ECs) is a key regulator of angiogenesis, a process essential for wound healing and tumor metastasis. Rap1a and Rap1b, 2 highly homologous small G proteins, are both required for angiogenesis in vivo and for normal EC responses to VEGF. Here we sought to determine the mechanism through which Rap1 promotes VEGF-mediated angiogenesis. Using lineage-restricted Rap1-knockout mice we show that Rap1-deficiency in endothelium leads to defective angiogenesis in vivo, in a dose-dependent manner. Using ECs obtained from Rap1-deficient mice we demonstrate that Rap1b promotes VEGF-VEGFR2 kinase activation and regulates integrin activation. Importantly, the Rap1b-dependent VEGF-VEGFR2 activation is in part mediated via integrin ?v?3. Furthermore, in an in vivo model of zebrafish angiogenesis, we demonstrate that Rap1b is essential for the sprouting of intersomitic vessels, a process known to be dependent on VEGF signaling. Using 2 distinct pharmacologic VEGFR2 inhibitors we show that Rap1b and VEGFR2 act additively to control angiogenesis in vivo. We conclude that Rap1b promotes VEGF-mediated angiogenesis by promoting VEGFR2 activation in ECs via integrin ?v?3. These results provide a novel insight into the role of Rap1 in VEGF signaling in ECs.

Lakshmikanthan, Sribalaji; Sobczak, Magdalena; Chun, Changzoon; Henschel, Angela; Dargatz, Jillian; Ramchandran, Ramani

2011-01-01

243

Involvement of Mitogen-Activated Protein Kinase Pathways in Staphylococcus aureus Invasion of Normal Osteoblasts  

PubMed Central

Staphylococcus aureus invades osteoblasts and can persist in the intracellular environment. The present study examined the role of osteoblast mitogen-activated protein kinase (MAPK) pathways in bacterial invasion. S. aureus infection of normal human and mouse osteoblasts resulted in an increase in the phosphorylation of the extracellular signal-regulated protein kinases (ERK 1 and 2). This stimulation of ERK 1 and 2 correlated with the time course of S. aureus invasion, and bacterial adherence induced the MAPK pathway. ERK 1 and 2 phosphorylation was time and dose dependent and required active S. aureus gene expression for maximal induction. The nonpathogenic Staphylococcus carnosus was also able to induce ERK 1 and 2 phosphorylation, albeit at lower levels than S. aureus. Phosphorylation of the stress-activated protein kinases was increased in both infected human and mouse osteoblasts; however, the p38 MAPK pathway was not activated in response to S. aureus. Finally, the transcription factor c-Jun, but not Elk-1 or ATF-2, was phosphorylated in response to S. aureus infection.

Ellington, John K.; Elhofy, Adam; Bost, Kenneth L.; Hudson, Michael C.

2001-01-01

244

Oxidative stress-mediated iNKT-cell activation is involved in COPD pathogenesis  

PubMed Central

Chronic obstructive pulmonary disease (COPD) is a major clinical challenge mostly due to cigarette smoke (CS) exposure. Invariant natural killer T (iNKT) cells are potent immunoregulatory cells that have a crucial role in inflammation. In the current study, we investigate the role of iNKT cells in COPD pathogenesis. The frequency of activated NKT cells was found to be increased in peripheral blood of COPD patients relative to controls. In mice chronically exposed to CS, activated iNKT cells accumulated in the lungs and strongly contributed to the pathogenesis. The detrimental role of iNKT cells was confirmed in an acute model of oxidative stress, an effect that depended on interleukin (IL)-17. CS extracts directly activated mouse and human dendritic cells (DC) and airway epithelial cells (AECs) to trigger interferon? and/or IL-17 production by iNKT cells, an effect ablated by the anti-oxidant N-acetylcystein. In mice, this treatment abrogates iNKT-cell accumulation in the lung and abolished the development of COPD. Together, activation of iNKT cells by oxidative stress in DC and AECs participates in the development of experimental COPD, a finding that might be exploited at a therapeutic level.

Pichavant, M; Remy, G; Bekaert, S; Le Rouzic, O; Kervoaze, G; Vilain, E; Just, N; Tillie-Leblond, I; Trottein, F; Cataldo, D; Gosset, P

2014-01-01

245

Erucylphosphocholine-induced apoptosis in glioma cells: involvement of death receptor signalling and caspase activation.  

PubMed

Erucylphosphocholine (ErPC) is a promising anti-neoplastic drug for the treatment of malignant brain tumours. It exerts strong anti-cancer activity in vivo and in vitro and induces apoptosis even in chemoresistant glioma cell lines. The purpose of this study was to expand on our previous observations on the potential mechanisms of ErPC-mediated apoptosis with a focus on death receptor activation and the caspase network. A172 and T98G glioma cells were treated with ErPC for up to 48 h. ErPC effects on the expression of the tumour necrosis factor (TNF) and TNF-related apoptosis-inducing ligand (TRAIL) receptor system, and on caspase activation were determined. ErPC had no effect on the expression of TNFalpha or TRAIL. Inhibition of the TNF or TRAIL signalling pathway with antagonistic antibodies or fusion proteins did not affect apoptosis induced by ErPC, and a dominant-negative FADD construct did not abolish ErPC-induced effects. Western blot analysis indicated that ErPC-triggered apoptosis resulted in a time-dependent processing of caspases-3, -7, -8 and -9 into their respective active subunits. Co-treatment of A172 cells with different caspase inhibitors prevented apoptosis but did not abrogate cell death. These data suggest that A172 cells might have an additional caspase-independent pathway that insures cell death and guarantees killing of those tumour cells whose caspase pathway is incomplete. PMID:12358763

Kugler, Wilfried; Erdlenbruch, Bernhard; Jünemann, Anja; Heinemann, Dagmar; Eibl, Hansjörg; Lakomek, Max

2002-09-01

246

School-based extracurricular activity involvement and adolescent self-esteem: a growth-curve analysis.  

PubMed

Research on adolescent self-esteem indicates that adolescence is a time in which individuals experience important changes in their physical, cognitive, and social identities. Prior research suggests that there is a positive relationship between an adolescent's participation in structured extracurricular activities and well-being in a variety of domains, and some research indicates that these relationships may be dependent on the type of activities in which adolescents participate. Building on previous research, a growth-curve analysis was utilized to examine self-esteem trajectories from adolescence (age 14) to young adulthood (age 26). Using 3 waves of data from National Longitudinal Study of Adolescent Health (n = 5,399; 47.8% male), the analysis estimated a hierarchical growth-curve model emphasizing the effects of age and type of school-based extracurricular activity portfolio, including sports and school clubs, on self-esteem. The results indicated that age had a linear relationship with self-esteem over time. Changes in both the initial level of self-esteem and the growth of self-esteem over time were significantly influenced by the type of extracurricular activity portfolio. The findings were consistent across race and sex. The results support the utility of examining the longitudinal impact of portfolio type on well-being outcomes. PMID:20495855

Kort-Butler, Lisa A; Hagewen, Kellie J

2011-05-01

247

School-Based Extracurricular Activity Involvement and Adolescent Self-Esteem: A Growth-Curve Analysis  

ERIC Educational Resources Information Center

Research on adolescent self-esteem indicates that adolescence is a time in which individuals experience important changes in their physical, cognitive, and social identities. Prior research suggests that there is a positive relationship between an adolescent's participation in structured extracurricular activities and well-being in a variety of…

Kort-Butler, Lisa A.; Hagewen, Kellie J.

2011-01-01

248

Hypnosis Modulates Activity in Brain Structures Involved in the Regulation of Consciousness  

Microsoft Academic Search

The notion of consciousness is at the core of an ongoing debate on the existence and nature of hypnotic states. Previously, we have described changes in brain activity associated with hypnosis (Rainville, Hofbauer, Paus, Duncan, Bushnell, & Price, 1999). Here, we replicate and extend those findings using positron emission tomography (PET) in 10 normal volunteers. Immediately after each of 8

Pierre Rainville; Robert K. Hofbauer; M. Catherine Bushnell; Gary H. Duncan; Donald D. Price

2002-01-01

249

76 FR 76935 - Impact of Implementing the Chemical Weapons Convention (CWC) on Commercial Activities Involving...  

Federal Register 2010, 2011, 2012, 2013

...for Comments Concerning the Impact of Adding Salts of Certain...would become subject to any impact that implementation of the...Annex on Chemicals, this could impact commercial activities in the...public comments on the BIS Freedom of Information Act...

2011-12-09

250

Families and School Personnel Involved in a Literacy and Physical Activity Partnership  

ERIC Educational Resources Information Center

A traditional part of American education has been to include the families in the educational process of their children. The needs and complexities of today's families and classrooms have never been greater. Programs and activities used with families, and school interactions 10 to 15 years ago are not effective for today's complex families and…

Richardson, James A.; Richardson, Maurine V.; Sacks, Mary Kathleen

2006-01-01

251

Endocrine regulation of mitochondrial activity: involvement of truncated RXRalpha and c-Erb Aalpha1 proteins  

Microsoft Academic Search

The importance of mitochondrial activ- ity has recently been extended to the regulation of developmental processes. Numerous pathologies asso- ciated with organelle's dysfunctions emphasize their physiological importance. However, regulation of mito- chondrial genome transcription, a key element for organelle's function, remains poorly understood. After characterization in the organelle of a truncated form of the triiodothyronine nuclear receptor (p43), a T3-

FRANCOIS CASAS; LAETITIA DAURY; STEPHANIE GRANDEMANGE; MURIEL BUSSON; PASCAL SEYER; RENEE HATIER; ANGEL CARAZO; GERARD CABELLO; CHANTAL WRUTNIAK-CABELLO

2003-01-01

252

Differential regulation of enzyme activities involved in aldehyde metabolism in the luminescent bacterium Vibrio harveyi.  

PubMed Central

The effects of catabolite repression and nutrient abundance on the activities of Vibrio harveyi enzymes known to be related to aldehyde metabolism were investigated. The growth of cells in complex medium containing glucose, which decreases in vivo luminescence and luciferase synthesis, also resulted in decreases in the specific activities of V. harveyi aldehyde dehydrogenase and acyl carrier protein acyltransferase as well as in the degree of fatty acylation of three bioluminescence-specific polypeptides (32, 42, and 57 kilodaltons), as monitored by sodium dodecyl sulfatepolyacrylamide gel electrophoresis. This repression was partially alleviated in glucose medium containing cyclic AMP. The acylation of the above-mentioned proteins, in addition to light emission and luciferase and acyltransferase activities, was also repressed when cells were grown in minimal medium, with partial recovery of these functions upon the addition of arginine. In contrast, aldehyde dehydrogenase activity was increased in minimal medium. These results suggest that the 42-, 57-, and 32-kilodalton proteins, which are responsible for the supply and reduction of fatty acids to form aldehydes for the luciferase reaction, are regulated in the same way as luciferase under the above-described conditions. However, aldehyde dehydrogenase, whose role in V. harveyi aldehyde metabolism is not yet known, is regulated in a different way with respect to nutrient composition. Images

Byers, D M; Bognar, A; Meighen, E A

1988-01-01

253

Fantasy Activity and the Televiewing Event: Considerations for an Information Processing Construct of Involvement.  

ERIC Educational Resources Information Center

The similarities between television viewing and fantasy activity (daydreaming, reverie, mind-wandering, internal dialogue) more than warrant the building of a theoretical construct, especially in the context of recent empirical research on television viewing consequences. A construct of the television viewing process, based on cognitive theories…

Lindlof, Thomas R.

254

Activity Involvement among Suicidal and Nonsuicidal High-Risk and Typical Adolescents.  

ERIC Educational Resources Information Center

Compared weekly activities among four groups of high risk and typical high school students: potential dropouts at suicide risk; typical youth at suicide risk; potential dropouts not at suicide risk; and typical youth not at suicide risk. Of the 1,286 participants, 39.4% of high risk and 30.1% of typical high school students screened in at suicide…

Mazza, James J.; Eggert, Leona L.

2001-01-01

255

Oxidative stress-mediated iNKT-cell activation is involved in COPD pathogenesis.  

PubMed

Chronic obstructive pulmonary disease (COPD) is a major clinical challenge mostly due to cigarette smoke (CS) exposure. Invariant natural killer T (iNKT) cells are potent immunoregulatory cells that have a crucial role in inflammation. In the current study, we investigate the role of iNKT cells in COPD pathogenesis. The frequency of activated NKT cells was found to be increased in peripheral blood of COPD patients relative to controls. In mice chronically exposed to CS, activated iNKT cells accumulated in the lungs and strongly contributed to the pathogenesis. The detrimental role of iNKT cells was confirmed in an acute model of oxidative stress, an effect that depended on interleukin (IL)-17. CS extracts directly activated mouse and human dendritic cells (DC) and airway epithelial cells (AECs) to trigger interferon? and/or IL-17 production by iNKT cells, an effect ablated by the anti-oxidant N-acetylcystein. In mice, this treatment abrogates iNKT-cell accumulation in the lung and abolished the development of COPD. Together, activation of iNKT cells by oxidative stress in DC and AECs participates in the development of experimental COPD, a finding that might be exploited at a therapeutic level. PMID:24172846

Pichavant, M; Rémy, G; Bekaert, S; Le Rouzic, O; Kervoaze, G; Vilain, E; Just, N; Tillie-Leblond, I; Trottein, F; Cataldo, D; Gosset, P

2014-05-01

256

Mechanism of activation of methyltransferases involved in translation by the Trm112 'hub' protein.  

PubMed

Methylation is a common modification encountered in DNA, RNA and proteins. It plays a central role in gene expression, protein function and mRNA translation. Prokaryotic and eukaryotic class I translation termination factors are methylated on the glutamine of the essential and universally conserved GGQ motif, in line with an important cellular role. In eukaryotes, this modification is performed by the Mtq2-Trm112 holoenzyme. Trm112 activates not only the Mtq2 catalytic subunit but also two other tRNA methyltransferases (Trm9 and Trm11). To understand the molecular mechanisms underlying methyltransferase activation by Trm112, we have determined the 3D structure of the Mtq2-Trm112 complex and mapped its active site. Using site-directed mutagenesis and in vivo functional experiments, we show that this structure can also serve as a model for the Trm9-Trm112 complex, supporting our hypothesis that Trm112 uses a common strategy to activate these three methyltransferases. PMID:21478168

Liger, Dominique; Mora, Liliana; Lazar, Noureddine; Figaro, Sabine; Henri, Julien; Scrima, Nathalie; Buckingham, Richard H; van Tilbeurgh, Herman; Heurgué-Hamard, Valérie; Graille, Marc

2011-08-01

257

5?-AMP Activated Protein Kinase is Involved in the Regulation of Myocardial ?-Oxidative Capacity in Mice  

PubMed Central

5?-adenosine monophosphate-activated protein kinase (AMPK) is considered central in regulation of energy status and substrate utilization within cells. In heart failure the energetic state is compromised and substrate metabolism is altered. We hypothesized that this could be linked to changes in AMPK activity and we therefore investigated mitochondrial oxidative phosphorylation capacity from the oxidation of long- and medium-chain fatty acids (LCFA and MCFA) in cardiomyocytes from young and old mice expressing a dominant negative AMPK?2 (AMPK?2-KD) construct and their wildtype (WT) littermates. We found a 35–45% (P?activity (14/21%, P?activity or progressing age. Expression of regulatory proteins of glycolysis and glycogen breakdown showed equivocal effects of age and genotype. These results illustrate that AMPK is necessary for normal mitochondrial function in the heart and that decreased AMPK activity may lead to an altered energetic state as a consequence of reduced capacity to oxidize MCFA. We did not identify any clear aging effects on mitochondrial function.

Stride, Nis; Larsen, Steen; Treebak, Jonas Thue; Hansen, Christina Neigaard; Hey-Mogensen, Martin; Speerschneider, Tobias; Jensen, Thomas E.; Jeppesen, Jacob; Wojtaszewski, J?rgen F. P.; Richter, Erik A.; K?ber, Lars; Dela, Flemming

2012-01-01

258

Functional analysis of an epitope in the S2 subunit of the murine coronavirus spike protein: involvement in fusion activity  

Microsoft Academic Search

The monoclonal antibody (MAb) 5B19.2, which has virus-neutralizing and fusion inhibition activities, binds to an epitope (S2A) consisting of nine hydro- phobic amino acids in the S2 subunit of the mouse hepatitis virus (MHV) spike (S) protein. This sug- gests that the S2A epitope may be involved in binding the virus to the MHV receptor and\\/or in virus-cell fusion. Co-immunoprecipitation

Fumihiro Taguchi; Yohko K. Shimazaki

2000-01-01

259

Down-regulation of Rap1 activity is involved in ephrinB1-induced cell contraction  

Microsoft Academic Search

Ephrins are cell surface ligands that activate Eph receptor tyrosine kinases. This ligand-receptor interaction plays a central role in the sorting of cells. We have previously shown that the ephrinB-EphB signalling pathway is also involved in the migration of intestinal precursor cells along the crypts. Using the colon cell line DLD1 expressing the EphB2 receptor, we showed that stimulation of

Eduard Batlle; J. C. Clevers

2005-01-01

260

Signal Cross Talks for Sustained MAPK Activation and Cell Migration Mediated by Reactive Oxygen Species: The Involvement in Tumor Progression  

Microsoft Academic Search

\\u000a Signal transduction exerted by the microenvironment around the primary tumor locus may trigger tumor metastasis especially\\u000a at the migration stage. Sustained mitogen activated protein kinase (MAPK) signaling involved in uncontrolled tumor cell migration\\u000a rely on the cross talks between integrin, receptor tyrosine kinas (RTK) and protein kinase C (PKC). The molecular mechanisms\\u000a for cross talking between these migration-related signal cascades

Chi-Tan Hu; Jia-Ru Wu; Wen-Sheng Wu

261

Synergistic anticancer activity of 1,25-dihydroxyvitamin D 3 and immune cytokines: the involvement of reactive oxygen species  

Microsoft Academic Search

It was previously shown that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) enhances the cytotoxic activity of tumor necrosis factor ? (TNF?), doxorubicin and menadione. A feature shared by these anticancer agents is the involvement of reactive oxygen species (ROS) in their action. In this work we found that 1,25(OH)2D3 acted synergistically with interleukin 1 ? (IL-1?) or interleukin 6 (IL-6) to inhibit the

Ruth Koren; Dafna Rocker; Ofira Kotestiano; Uri A Liberman; Amiram Ravid

2000-01-01

262

Prevalence of disabled people involved in Spanish Civil Guard's police activity.  

PubMed

Improving interventions with victims and offenders with disabilities requires analysis of the degree of prevalence of crimes in which these people are involved. For this purpose, data regarding interventions made by the Spanish Civil Guard between 2008 and 2010, in which 2099 people had some kind of disability, have been collected and analyzed, with particular regard to criminal offenses (felonies and/or misdemeanors). In this study, the relationship between the types of disability a person has and other variables like their connection to the incident, their gender, age, the relationship between victim and perpetrator, and the time and place of the events were all taken into consideration. The results show that most of the victims with disabilities served by the Spanish Civil Guard were male. The interventions were mainly aid and rescues. Criminal offenses were only 20% of the events. PMID:24029801

González, José L; Cendra, Jacobo; Manzanero, Antonio L

2013-11-01

263

Designing active flutter suppression for high-dimensional aeroelastic systems involving a control delay  

NASA Astrophysics Data System (ADS)

Many linear control laws, such as optimal controllers and classical controllers, have seen their applications to suppressing the aeroelastic vibrations of the high-dimensional aeroelastic system. However, those conventional control laws may not work effectively if the high-dimensional aeroelastic system involves a control delay. The paper reveals the effect of input time delay on the stability of a controlled high-dimensional aeroelastic system in an incompressible flow field and presents a new optimal control law to suppress the flutter of the high-dimensional aeroelastic system with an input time delay in the control loop. The procedure of designing the proposed control law includes three steps as follows. The first step is to convert the system described by a set of differential equations with a time delay into a set of difference equations involving discrete delay terms by using zero-order holder. The second step, exhibiting the novelty of the study, is to transform the difference equations with delay terms into a set of delay-free difference equations via a state transformation. The third step is to use the theory of linear control, say, the theory of Linear Quadratic Gaussian (LQG), to complete the design of controller by solving an equivalent Riccati equation. The paper demonstrates the efficacy of proposed method in designing the flutter suppression controller for a wind-tunnel model of Multiple-Actuated Wing. The new method works much better than classical feedback and conventional LQG controllers, both of which do not take the input time delay into account and may induce instability, when the input time delay becomes significant.

Huang, Rui; Hu, Haiyan; Zhao, Yonghui

2012-10-01

264

Lamprey lymphocyte-like cells express homologs of genes involved in immunologically relevant activities of mammalian lymphocytes  

PubMed Central

To shed light on the origin of adaptive immunity, a cDNA library was prepared from purified lymphocyte-like cells of a jawless vertebrate, the sea lamprey (Petromyzon marinus). Randomly selected cDNA clones were sequenced, and their homologies to proteins in the databases were determined. Of the sequences homologous to proteins involved in immune responses, five were selected for further characterization. Their encoding genes corresponded to loci that in jawed vertebrates are essential for activities of lymphocytes. These activities include regulation of T and B cell stimulation and proliferation (CD45); stabilization of molecular complexes involved in lymphocyte activation, adhesion, migration, and differentiation (CD9/CD81); adaptor functions in signaling leading to the activation of B lymphocytes (BCAP) and T lymphocytes (CAST); and amino acid transport associated with cell activation (CD98). The presence of these genes in the lamprey genome and their expression in lymphocyte-like cells support the notion that these cells perform many of the functions of gnathostome lymphocytes. It reopens the question of the stage jawless fishes reached in the evolution of their immune system.

Uinuk-ool, Tatiana; Mayer, Werner E.; Sato, Akie; Dongak, Roman; Cooper, Max D.; Klein, Jan

2002-01-01

265

Rapid activation of Na+/H+-exchange in MDCK cells by aldosterone involves MAP-kinase ERK1/2.  

PubMed

The mineralocorticoid aldosterone is essential for the adequate regulation of electrolyte homeostasis, extracellular volume and blood pressure. As a steroid hormone it influences cellular functions by genomic actions. Previously it has been shown that aldosterone can activate Na+/H+-exchange (NHE) by a rapid, nongenomic mechanism. Because (1) NHE can be regulated by ERK1/2 (extracellular signal-regulated kinase) and (2) steroids have been reported to rapidly activate ERK1/2, we tested the hypothesis that activation of NHE by aldosterone involves ERK1/2, using MDCK-C11 cells. We show that nanomolar concentrations of aldosterone induce a rapid, non-genomic activation of NHE, which is characterized by an increased affinity for H+ with minor changes in the maximum transport rate. Accordingly, aldosterone led to an increase of cytosolic steady-state pH. The aldosterone-induced activation of NHE was prevented by the two specific inhibitors of ERK1/2 activation, PD 98059 (2.5 x 10(-5) mol/l) and U0126 (10(-5) mol/l). Furthermore, in the presence of U0126 there was no aldosterone-induced increase of steady-state pH. Finally, aldosterone induced a rapid phosphorylation of ERK1/2, indicating its ability to activate ERK1/2. The data presented here support the hypothesis that the rapid activation of NHE by aldosterone at nanomolar concentrations involves ERK1/2. Thus, in certain cell types, the MAPK cascade may represent an additional pathway mediating rapid aldosterone effects. PMID:11316261

Gekle, M; Freudinger, R; Mildenberger, S; Schenk, K; Marschitz, I; Schramek, H

2001-03-01

266

Factors Involved in the Regulation of a Ligninase Activity in Phanerochaete chrysosporium  

PubMed Central

The regulation of an H2O2-dependent ligninolytic activity was examined in the wood decay fungus Phanerochaete chrysosporium. The ligninase appears in cultures upon limitation for nitrogen or carbohydrate and is suppressed by excess nutrients, by cycloheximide, or by culture agitation. Activity is increased by idiophasic exposure of cultures to 100% O2. Elevated levels of ligninase and, in some cases, of extracellular H2O2 production are detected after brief incubation of cultures with lignins or lignin substructure models, with the secondary metabolite veratryl alcohol, or with other related compounds. It is concluded that lignin degradation (lignin ? CO2) by this organism is regulated in part at the level of the ligninase, which is apparently inducible by its substrates or their degradation products.

Faison, B. D.; Kirk, T. K.

1985-01-01

267

Possible involvement of lignin structure in anti-influenza virus activity.  

PubMed

Commercial lignins suppressed the growth of influenza A virus infecting MDCK cells, and the RNA-dependent RNA synthesis, as efficiently as the high-molecular weight fractions extracted from pine cone of Pinus parviflora Sieb. et Zucc. The anti-influenza A virus activity of both pine cone extract and commercial alkali-lignin was considerably reduced by treatment with sodium chlorite, but was not affected by sulfuric acid or trifluoroacetic acid. The degraded components of lignin, various synthesized polyphenols unrelated to lignin, and natural and chemically modified glucans, were not appreciably inhibitory. The data suggest that the polymerized phenolic structure of lignified materials is responsible for the anti-influenza A virus activity. PMID:2035999

Harada, H; Sakagami, H; Nagata, K; Oh-hara, T; Kawazoe, Y; Ishihama, A; Hata, N; Misawa, Y; Terada, H; Konno, K

1991-01-01

268

Involvement of IL32 in activation-induced cell death in T cells  

Microsoft Academic Search

NK cell transcript 4 (NK4), now denoted as IL-32, was originally identified as a transcript whose expression was increased in activated NK cells. It has been very recently demonstrated that NK4 is secreted from several cells upon the stimulation of some inflammatory cytokines such as IL-18, IL-1b, IFN-c and IL-12. Furthermore, NK4 induces production of tumor necrosis factor, macrophage inflammatory

Chiho God; Taisuke Kanaji; Sachiko Kanaji; Go Tanaka; Kazuhiko Arima; Shigeaki Ohno; Kenji Izuhara

2006-01-01

269

Characterization of Mechanisms Involved in Transrepression of NF-kB by Activated Glucocorticoid Receptors  

Microsoft Academic Search

Glucocorticoids are potent immunosuppressants which work in part by inhibiting cytokine gene transcrip- tion. We show here that NF-kB, an important regulator of numerous cytokine genes, is functionally inhibited by the synthetic glucocorticoid dexamethasone (DEX). In transfection experiments, DEX treatment in the presence of cotransfected glucocorticoid receptor (GR) inhibits NF-kB p65-mediated gene expression and p65 inhibits GR activation of a

ROBERT I. SCHEINMAN; ANTONIO GUALBERTO; CHRISTINE M. JEWELL; JOHN A. CIDLOWSKI; ANDALBERT S. BALDWIN

270

Involvement of Platelet-Activating Factor in Ultraviolet B-Induced Hyperalgesia  

Microsoft Academic Search

Ultraviolet B (UVB) radiation causes cutaneous inflammation. One important clinical consequence of UVB-induced inflammation is increased pain or hyperalgesia, which is likely mediated by enhanced sensitivity of cutaneous sensory neurons. Previous studies have demonstrated that UVB radiation generates the lipid mediator, platelet-activating factor (PAF), as well as oxidized phospholipids that act as PAF-mimetics. These substances exert effects through the PAF

Qiwei Zhang; Leslie A Sitzman; Mohammad Al-Hassani; Shanbao Cai; Karen E Pollok; Jeffrey B Travers; Cynthia M Hingtgen

2009-01-01

271

Edwardsiella ictaluri LuxS: activity, expression, and involvement in pathogenicity.  

PubMed

Edwardsiella ictaluri is a Gram-negative bacterium and the causative agent of enteric septicemia of catfish. In this study, we examined the expression and function of the LuxS from a pathogenic E. ictaluri strain, 1901. J901 was found to produce autoinducer 2 (AI-2) activity that maximized at mid-logarithmic phase and was enhanced by glucose and repressed by high temperature. Consistently, a luxS gene (luxSEi) was identified in J901, whose expression was regulated by cell density, glucose, and temperature in a manner similar to that observed with AI-2 activity. Further analysis showed that LuxSEi is a biologically active AI-2 synthase that was able to complement the luxS-defective phenotype of Escherichia coli DH5alpha. To examine the functional importance of LuxSEi, a genetically modified variant of J901, J901Ri, was constructed, in which luxSEi, expression was blocked by RNA interference. Compared to the wild type, J901Ri was (i) reduced in AI-2 activity to a level of 59% of that of the wild type; (ii) impaired in both planktonic and biofilm growth; (iii) significantly attenuated in the ability to infect cultured fish cells and to cause mortality in infected fish; (iv) unable to induce the expression of certain virulence-associated genes. Addition of exogenous AI-2 failed to rescue the growth defect of J901Ri as free-living cells but restored biofilm production and the expression of virulence genes to levels comparable to those of the wild type. Taken together, these results indicate that LuxSEi is a functional AI-2 synthase that is required for optimal cellular growth and host infection. PMID:23484409

Zhang, Min; Sun, Li

2012-01-01

272

Protease-activated receptor 1-dependent neuronal damage involves NMDA receptor function  

PubMed Central

Protease-activated receptor 1 (PAR1) is a G-protein coupled receptor that is expressed throughout the central nervous system. PAR1 activation by brain-derived as well as blood-derived proteases has been shown to have variable and complex effects in a variety of animal models of neuronal injury and inflammation. In this study, we have evaluated the effects of PAR1 on lesion volume in wild-type or PAR1?/? C57Bl/6 mice subjected to transient occlusion of the middle cerebral artery or injected with NMDA in the striatum. We found that removal of PAR1 reduced infarct volume following transient focal ischemia to 57% of control. Removal of PAR1 or application of a PAR1 antagonist also reduced the neuronal injury associated with intrastriatal injection of NMDA to 60% of control. To explore whether NMDA receptor potentiation by PAR1 activation contributes to the harmful effects of PAR1, we investigated the effect of NMDA receptor antagonists on the neuroprotective phenotype of PAR1?/? mice. We found that MK801 reduced penumbral but not core neuronal injury in mice subjected to transient middle cerebral artery occlusion or intrastriatal NMDA injection. Lesion volumes in both models were not significantly different between PAR1?/? mice treated with and without MK801. Use of the NMDA receptor antagonist and dissociative anesthetic ketamine also renders NMDA-induced lesion volumes identical in PAR1?/? mice and wild-type mice. These data suggest that the ability of PAR1 activation to potentiate NMDA receptor function may underlie its harmful actions during injury.

Hamill, Cecily E.; Mannaioni, Guido; Lyuboslavsky, Polina; Sastre, Aristide A.; Traynelis, Stephen F.

2009-01-01

273

Mechanism of glial activation by S100B: involvement of the transcription factor NF?B  

Microsoft Academic Search

Compelling evidence links chronic activation of glia and the subsequent cycle of neuroinflammation and neuronal dysfunction to the progression of neurodegeneration in disorders such as Alzheimer’s disease (AD). S100B, a glial-derived cytokine, is significantly elevated in the brains of AD patients and high concentrations of S100B are believed to be detrimental to brain function. As a first step toward elucidating

Amy G. M Lam; Tanuja Koppal; Keith T Akama; Ling Guo; Jeffrey M Craft; Barat Samy; James P Schavocky; D Martin Watterson; Linda J Van Eldik

2001-01-01

274

Identification of a Second Arcanobacterium pyogenes Neuraminidase and Involvement of Neuraminidase Activity in Host Cell Adhesion  

Microsoft Academic Search

Arcanobacterium pyogenes, a common inhabitant of the upper respiratory and urogenital tracts of econom- ically important animals, such as cattle and swine, is also an opportunistic pathogen associated with suppu- rative infections in these animals. A. pyogenes expresses neuraminidase activity encoded by the nanH gene, and previously, construction of a nanH mutant of A. pyogenes BBR1 indicated that a second

B. Helen Jost; J. Glenn Songer; Stephen J. Billington

2002-01-01

275

Nuclear gating of a Drosophila dCREB2 activator is involved in memory formation.  

PubMed

The transcription factor CREB is an important regulator of many adaptive processes in neurons, including sleep, cellular homeostasis, and memory formation. The Drosophila dCREB2 family includes multiple protein isoforms generated from a single gene. Overexpression of an activator or blocker isoform has been shown to enhance or block memory formation, but the molecular mechanisms underlying these phenomena remain unclear. In the present study, we generate isoform-specific antibodies and new transgenic flies to track and manipulate the activity of different dCREB2 isoforms during memory formation. We find that nuclear accumulation of a dCREB2 activator-related species, p35+, is dynamically regulated during memory formation. Furthermore, various dCREB2 genetic manipulations that enhance or block memory formation correspondingly increase or decrease p35+ levels in the nucleus. Finally, we show that overexpression of S6K can enhance memory formation and increase p35+ nuclear abundance. Taken together, these results suggest that regulation of dCREB2 localization may be a key molecular convergence point in the coordinated host of events that lead to memory formation. PMID:24076014

Fropf, Robin; Tubon, Thomas C; Yin, Jerry C P

2013-11-01

276

GABAergic Neural Activity Involved in Salicylate-Induced Auditory Cortex Gain Enhancement  

PubMed Central

Although high doses of sodium salicylate impair cochlear function, it paradoxically enhances sound-evoked activity in the auditory cortex (AC) and augments acoustic startle reflex responses, neural and behavioral metrics associated with hyperexcitability and hyperacusis. To explore the neural mechanisms underlying salicylate-induced hyperexcitability and “increased central gain”, we examined the effects of ?-aminobutyric acid (GABA) receptor agonists and antagonists on salicylate-induced hyperexcitability in the AC and startle reflex responses. Consistent with our previous findings, local or systemic application of salicylate significantly increased the amplitude of sound-evoked AC neural activity, but generally reduced spontaneous activity in the AC. Systemic injection of salicylate also significantly increased the acoustic startle reflex. S-baclofen or R-baclofen, GABA-B agonists, which suppressed sound-evoked AC neural firing rate and local field potentials, also suppressed the salicylate-induced enhancement of the AC field potential and the acoustic startle reflex. Local application of vigabatrin, which enhances GABA concentration in the brain, suppressed the salicylate-induced enhancement of AC firing rate. Systemic injection of vigabatrin also reduced the salicylate-induced enhancement of acoustic startle reflex. Collectively, these results suggest that the sound-evoked behavioral and neural hyperactivity induced by salicylate may arise from a salicylate-induced suppression GABAergic inhibition in the AC.

Lu, Jianzhong; Lobarinas, Edward; Deng, Anchun; Goodey, Ronald; Stolzberg, Daniel; Salvi, Richard J.; Sun, Wei

2011-01-01

277

Cisplatin Nephrotoxicity Involves Mitochondrial Injury with Impaired Tubular Mitochondrial Enzyme Activity  

PubMed Central

Cisplatin is a widely used antineoplastic agent. However, its major limitation is dose-dependent nephrotoxicity whose precise mechanism is poorly understood. Recent studies have suggested that mitochondrial dysfunction in tubular epithelium contributes to cisplatin-induced nephrotoxicity. Here the authors extend those findings by describing the role of an important electron transport chain enzyme, cytochrome c oxidase (COX). Immunohistochemistry for COX 1 protein demonstrated that, in response to cisplatin, expression was mostly maintained in focally damaged tubular epithelium. In contrast, COX enzyme activity in proximal tubules (by light microscopy) was decreased. Ultrastructural analysis of the cortex and outer stripe of the outer medulla showed decreased mitochondrial mass, disruption of cristae, and extensive mitochondrial swelling in proximal tubular epithelium. Functional electron microscopy showed that COX enzyme activity was decreased in the remaining mitochondria in the proximal tubules but maintained in distal tubules. In summary, cisplatin-induced nephrotoxicity is associated with structural and functional damage to the mitochondria. More broadly, using functional electron microscopy to measure mitochondrial enzyme activity may generate mechanistic insights across a spectrum of renal disorders.

Ellezian, Lena; Brown, Dan; Horvath, Bela; Mukhopadhyay, Partha; Kalyanaraman, Balaraman; Parikh, Samir M.; Karumanchi, S. Ananth; Stillman, Isaac E.; Pacher, Pal

2012-01-01

278

Amidase activity involved in peptidoglycan biosynthesis in membranes of Micrococcus luteus (sodonensis).  

PubMed Central

Membrane suspensions prepared from Micrococcus luteus (sodonensis) in both the exponential and stationary phases of growth contained a transglycosidase activity capable of synthesizing linear peptidoglycan. Exponential-phase membranes also contained an N-acetylmuramyl-L-alanine amidase activity which degraded the peptidoglycan as it was formed. The product of this amidase was purified and found to be free pentapeptide. The amidase was specific for peptidoglycan and could not attack lower-molecular-weight substrates even though the susceptible bond was present. Crude cell wall preparations isolated from exponential-phase cells also contained high levels of amidase. This cell wall-bound amidase would preferentially degrade in vitro-synthesized peptidoglycan over its own cell wall. Amidase activity could be solubilized from both cell walls and membranes by Triton X-100 treatment, butanol extraction, or LiCl extraction. Both membrane- and cell wall-derived amidases, solubilized by LiCl extraction, appeared to be of high molecular weight (greater than 150,000). Once solubilized, these wall- and membrane-derived amidases could attack the cross-bridged peptidoglycan of purified native cell walls, whereas bound amidases could not.

Jensen, S E; Campbell, J N

1976-01-01

279

Antidepressant activity of astilbin: involvement of monoaminergic neurotransmitters and BDNF signal pathway.  

PubMed

Depression and related mood disorders are among the world's greatest public health problems. Previous studies have demonstrated that astilbin (AST) has broad pharmacological functions which may modulate numerous pathways, such as antioxidant, scavenging free radicals, anti-inflammatory and so on, similarly to some of other flavonoids. In this study, the antidepressant-like effect of AST was investigated using chronic unpredictable mild stress (CUMS) model of depression in mice. The results showed that chronic administration of AST at doses of 10, 20 and 40?mg/kg (intraperitoneally (i.p.), 21?d) reduced depressive-like behaviors of mice in the forced swim test (FST), tail suspension test (TST) and sucrose preference test (SPT) without affecting locomotor activity. AST increased the contents of serotonin (5-HT) and dopamine (DA) in the frontal cortex of CUMS mice. Additionally, it was shown that AST treatment restored the CUMS-induced inhibition of extracellular signal-regulated kinase (ERK) 1/2 and AKT phosphorylation in the frontal cortex, conformed to the brain-derived neurotrophic factor (BDNF) expression. Our findings suggest that AST has antidepressant activities and the mechanisms, at least in part, relate to up-regulation of monoaminergic neurotransmitters (5-HT and DA) and activation of the BDNF signaling pathway. PMID:24681540

Lv, Qiong-Qiong; Wu, Wen-Jie; Guo, Xiao-Liang; Liu, Rui-Li; Yang, Yu-Ping; Zhou, Du-Shuang; Zhang, Ji-Xia; Liu, Ju-Yuan

2014-06-01

280

Production of lysophosphatidic acid in blister fluid: involvement of a lysophospholipase D activity  

PubMed Central

Lysophosphatidic acid (LPA) is present in abundance in serum resulting from platelet activation and is also found in other biological fluids. LPA controls numerous cellular responses and plays a role in specific functions such as wound healing, especially in the skin. Nevertheless, its presence in the skin has never been investigated during wound healing, or in other situations. Since re-epithelialization occurs after blister rupture, the presence of LPA in blister fluids was investigated. Using a radioenzymatic assay, LPA was detected in 33 blister fluids originating from 24 bullous dermatoses, and at higher concentrations than in plasma. LPA concentration was independent of the type of dermatoses. In parallel, blister fluids contained a lysophospholipase D (LPLD) activity but no detectable phospholipase A2 activity. The expression of the LPLD autotaxin (ATX) and of LPA1-receptor were greatly increased in blister skin when compared to normal skin. Finally, LPA was found to have a positive effect on the migration of cultured keratinocytes. These results show that LPA is present in blister fluid synthesized by the LPLD ATX. Due to its ability to enhance keratinocyte migration, LPA in blister fluid could, via the LPA1-receptor, play an important role in re-epithelialization occuring after blister rupture.

Mazereeuw-Hautier, Juliette; Gres, Sandra; Fanguin, Madie; Cariven, Clotilde; Fauvel, Josette; Perret, Bertrand; Chap, Hugues; Salles, Jean-Pierre; Saulnier-Blache, Jean-Sebastien

2005-01-01

281

Regulation of ERK1/2 activity by ghrelin-activated growth hormone secretagogue receptor 1A involves a PLC/PKC? pathway  

PubMed Central

The growth hormone secretagogue receptor 1a (GHSR-1a) is a G-protein coupled receptor, involved in the biological actions of ghrelin by triggering inositol phosphates and calcium intracellular second messengers. It has also been reported that ghrelin could activate the 44- and 42-kDa extracellular signal-regulated protein kinases (ERK1/2) in different cell lines, but it is not clear whether this regulation is GHSR-1a dependent or not. To provide direct evidence for the coupling of GHSR-1a to ERK1/2 activation, this pathway has been studied in a heterologous expression system. Thus, in Chinese hamster ovary (CHO) cells we showed that ghrelin induced, via the human GHSR-1a, a transient and dose-dep endent activation of ERK1/2 leading to activation of the transcriptional factor Elk1. We then investigated the precise mechanisms involved in GHSR-1a-mediated ERK1/2 activation using various specific inhibitors and dominant-negative mutants and found that internalization of GHSR-1a was not necessary. Our results also indicate that phospholipase C (PLC) was involved in GHSR-1a-mediated ERK1/2 activation, however, pathways like tyrosine kinases, including Src, and phosphoinositide 3-kinases were not found to be involved. GHSR-1a-mediated ERK1/2 activation was abolished both by a general protein kinase C (PKC) inhibitor, Gö6983, and by PKC depletion using overnight pretreatment with phorbol ester. Moreover, the calcium chelator, BAPTA-AM, and the inhibitor of conventional PKCs, Gö6976, had no effect on the GHSR-1a-mediated ERK1/2 activation, suggesting the involvement of novel PKC isoforms (?, ?), but not conventional or atypical PKCs. Further analyses suggest that PKC? is required for the activation of ERK1/2. Taken together, these data suggest that ghrelin, through GHSR-1a, activates the Elk1 transcriptional factor and ERK1/2 by a PLC- and PKC?-dependent pathway.

Mousseaux, Delphine; Le Gallic, Lionel; Ryan, Joanne; Oiry, Catherine; Gagne, Didier; Fehrentz, Jean-Alain; Galleyrand, Jean-Claude; Martinez, Jean

2006-01-01

282

Iranian Commercial Activities: Foreign Firms Reported to Have Engaged in Certain Activities Involved Iran's Energy or Communications Sectors.  

National Technical Information Service (NTIS)

The Iran Threat Reduction and Syria Human Rights Act of 2012 and Senate reports 111-201 and 112-26 contain recurring mandates for GAO to report on firms engaging in certain types of commercial activities with Iran. Since 2010, in response to these mandate...

2014-01-01

283

Activism and Leadership Development: Examining the Relationship between College Student Activism Involvement and Socially Responsible Leadership Capacity  

ERIC Educational Resources Information Center

The purpose of this study was to examine the relationship between participation in student activism and leadership development among college students. This study applied the social change model of leadership development (SCM) as the theoretical model used to measure socially responsible leadership capacity in students. The study utilized data…

Page, Jeremy Dale

2010-01-01

284

Protein phosphatase and kinase activities possibly involved in exocytosis regulation in Paramecium tetraurelia.  

PubMed Central

In Paramecium tetraurelia cells synchronous exocytosis induced by aminoethyldextran (AED) is accompanied by an equally rapid dephosphorylation of a 63 kDa phosphoprotein (PP63) within 80 ms. In vivo, rephosphorylation occurs within a few seconds after AED triggering. In homogenates (P)P63 can be solubilized in all three phosphorylation states (phosphorylated, dephosphorylated and rephosphorylated) and thus tested in vitro. By using chelators of different divalent cations, de- and rephosphorylation of PP63 and P63 respectively can be achieved by an endogenous protein phosphatase/kinase system. Dephosphorylation occurs in the presence of EDTA, whereas in the presence of EGTA this was concealed by phosphorylation by endogenous kinase(s), thus indicating that phosphorylation of P63 is calcium-independent. Results obtained with protein phosphatase inhibitors (okadaic acid, calyculin A) allowed us to exclude a protein serine/threonine phosphatase of type I (with selective sensitivity in Paramecium). Protein phosphatase 2C is also less likely to be a candidate because of its requirement for high Mg2+ concentrations. According to previous evidence a protein serine/threonine phosphatase of type 2B (calcineurin; CaN) is possibly involved. We have now found that bovine brain CaN dephosphorylates PP63 in vitro. Taking into account the specific requirements of this phosphatase in vitro, with p-nitrophenyl phosphate as a substrate, we have isolated a cytosolic phosphatase of similar characteristics by combined preparative gel electrophoresis and affinity-column chromatography. In Paramecium this phosphatase also dephosphorylates PP63 in vitro (after 32P labelling in vivo). Using various combinations of ion exchange, affinity and hydrophobic interaction chromatography we have also isolated three different protein kinases from the soluble fraction, i.e. a cAMP-dependent protein kinase (PKA), a cGMP-dependent protein kinase (PKG) and a casein kinase. Among the kinases tested, PKA cannot phosphorylate P63, whereas either PKG or the casein kinase phosphorylate P63 in vitro. On the basis of these findings we propose that a protein phosphatase/kinase system is involved in the regulation of exocytosis in P. tetraurelia cells.

Kissmehl, R; Treptau, T; Hofer, H W; Plattner, H

1996-01-01

285

Different structures involved during ictal and interictal epileptic activity in malformations of cortical development: an EEG-fMRI study  

PubMed Central

Malformations of cortical development (MCDs) are commonly complicated by intractable focal epilepsy. Epileptogenesis in these disorders is not well understood and may depend on the type of MCD. The cellular mechanisms involved in interictal and ictal events are notably different, and could be influenced independently by the type of pathology. We evaluated the relationship between interictal and ictal zones in eight patients with different types of MCD in order to better understand the generation of these activities: four had nodular heterotopia, two focal cortical dysplasia and two subcortical band heterotopia (double-cortex). We used the non-invasive EEG-fMRI technique to record simultaneously all cerebral structures with a high spatio-temporal resolution. We recorded interictal and ictal events during the same session. Ictal events were either electrical only or clinical with minimal motion. BOLD changes were found in the focal cortical dysplasia during interictal and ictal epileptiform events in the two patients with this disorder. Heterotopic and normal cortices were involved in BOLD changes during interictal and ictal events in the two patients with double cortex, but the maximum BOLD response was in the heterotopic band in both patients. Only two of the four patients with nodular heterotopia showed involvement of a nodule during interictal activity. During seizures, although BOLD changes affected the lesion in two patients, the maximum was always in the overlying cortex and never in the heterotopia. For two patients intracranial recordings were available and confirm our findings. The dysplastic cortex and the heterotopic cortex of band heterotopia were involved in interictal and seizure processes. Even if the nodular gray matter heterotopia may have the cellular substrate to produce interictal events, the often abnormal overlying cortex is more likely to be involved during the seizures. The non-invasive BOLD study of interictal and ictal events in MCD patients may help to understand the role of the lesion in epileptogenesis and also determine the potential surgical target.

Tyvaert, L.; Hawco, C.; Kobayashi, E.; LeVan, P.; Dubeau, F.; Gotman, J.

2013-01-01

286

Active cell movements coupled to positional induction are involved in lineage segregation in the mouse blastocyst  

PubMed Central

In the mouse blastocyst, some cells of the inner cell mass (ICM) develop into primitive endoderm (PE) at the surface, while deeper cells form the epiblast. It remained unclear whether the position of cells determines their fate, such that gene expression is adjusted to cell position, or if cells are pre-specified at random positions and then sort. We have tracked and characterised dynamics of all ICM cells from the early to late blastocyst stage. Time-lapse microscopy in H2B-EGFP embryos shows that a large proportion of ICM cells change position between the surface and deeper compartments. Most of this cell movement depends on actin and is associated with cell protrusions. We also find that while most cells are precursors for only one lineage, some give rise to both, indicating that lineage segregation is not complete in the early ICM. Finally, changing the expression levels of the PE marker Gata6 reveals that it is required in surface cells but not sufficient for the re-positioning of deeper cells. We provide evidence that Wnt9A, known to be expressed in the surface ICM, facilitates re-positioning of Gata6-expressing cells. Combining these experimental results with computer modelling suggests that PE formation involves both cell sorting movements and position-dependent induction.

Meilhac, Sigolene M.; Adams, Richard J.; Morris, Samantha A.; Danckaert, Anne; Le Garrec, Jean-Francois; Zernicka-Goetz, Magdalena

2012-01-01

287

Duplicate maize Wrinkled1 transcription factors activate target genes involved in seed oil biosynthesis.  

PubMed

WRINKLED1 (WRI1), a key regulator of seed oil biosynthesis in Arabidopsis (Arabidopsis thaliana), was duplicated during the genome amplification of the cereal ancestor genome 90 million years ago. Both maize (Zea mays) coorthologs ZmWri1a and ZmWri1b show a strong transcriptional induction during the early filling stage of the embryo and complement the reduced fatty acid content of Arabidopsis wri1-4 seeds, suggesting conservation of molecular function. Overexpression of ZmWri1a not only increases the fatty acid content of the mature maize grain but also the content of certain amino acids, of several compounds involved in amino acid biosynthesis, and of two intermediates of the tricarboxylic acid cycle. Transcriptomic experiments identified 18 putative target genes of this transcription factor, 12 of which contain in their upstream regions an AW box, the cis-element bound by AtWRI1. In addition to functions related to late glycolysis and fatty acid biosynthesis in plastids, the target genes also have functions related to coenzyme A biosynthesis in mitochondria and the production of glycerol backbones for triacylglycerol biosynthesis in the cytoplasm. Interestingly, the higher seed oil content in ZmWri1a overexpression lines is not accompanied by a reduction in starch, thus opening possibilities for the use of the transgenic maize lines in breeding programs. PMID:21474435

Pouvreau, Benjamin; Baud, Sébastien; Vernoud, Vanessa; Morin, Valérie; Py, Cyrille; Gendrot, Ghislaine; Pichon, Jean-Philippe; Rouster, Jacques; Paul, Wyatt; Rogowsky, Peter M

2011-06-01

288

Nicotine-induced neuroprotection against ischemic injury involves activation of endocannabinoid system in rats.  

PubMed

Nicotine has been reported to exert certain protective effect in the Parkinson's and Alzheimer's diseases. Whether it has a similar action in focal cerebral ischemia was unclear. In the present study, rats received either an injection of (-)-nicotine hydrogen tartrate salt (1.2 mg/kg, i.p.) or the vehicle 2 h before the 120 min middle cerebral artery occlusion. Neurological deficits and histological injury were assessed at 24 h after reperfusion. The content of endocannabinoids and the expression of cannabinoid receptor CB1 in brain tissues were determined at different time points after nicotine administration. Results showed that nicotine administration ameliorated neurological deficits and reduced infarct volume induced by cerebral ischemia in the rats. The neuroprotective effect was partially reversed by CB1 blockage. The content of the endocannabinoids N-arachidonylethanolamine and 2-arachidonoylglycerol, as well as the expression of cannabinoid receptor CB1 were up-regulated in brain tissues after nicotine delivery. These results suggest that endogenous cannabinoid system is involved in the nicotine-induced neuroprotection against transient focal cerebral ischemia. PMID:23192660

Chen, Yu; Nie, Huang; Tian, Li; Tong, Li; Yang, Lujia; Lao, Ning; Dong, Hailong; Sang, Hanfei; Xiong, Lize

2013-02-01

289

A Region of ?K Involved in Promoter Activation by GerE in Bacillus subtilis  

PubMed Central

During endospore formation in Bacillus subtilis, the DNA binding protein GerE stimulates transcription from several promoters that are used by RNA polymerase containing ?K. GerE binds to a site on one of these promoters, cotX, that overlaps its ?35 region. We tested the model that GerE interacts with ?K at the cotX promoter by seeking amino acid substitutions in ?K that interfered with GerE-dependent activation of the cotX promoter but which did not affect utilization of the ?K-dependent, GerE-independent promoter gerE. We identified two amino acid substitutions in ?K, E216K and H225Y, that decrease cotX promoter utilization but do not affect gerE promoter activity. Alanine substitutions at these positions had similar effects. We also examined the effects of the E216A and H225Y substitutions in ?K on transcription in vitro. We found that these substitutions specifically reduced utilization of the cotX promoter. These and other results suggest that the amino acid residues at positions 216 and 225 are required for GerE-dependent cotX promoter activity, that the histidine at position 225 of ?K may interact with GerE at the cotX promoter, and that this interaction may facilitate the initial binding of ?K RNA polymerase to the cotX promoter. We also found that the alanine substitutions at positions 216 and 225 of ?K had no effect on utilization of the GerE-dependent promoter cotD, which contains GerE binding sites that do not overlap with its ?35 region.

Wade, Kathryn H.; Schyns, Ghislain; Opdyke, Jason A.; Moran, Charles P.

1999-01-01

290

The gastroprotective effect of menthol: involvement of anti-apoptotic, antioxidant and anti-inflammatory activities.  

PubMed

The aim of this research was to investigate the anti-apoptotic, antioxidant and anti-inflammatory properties of menthol against ethanol-induced gastric ulcers in rats. Wistar rats were orally treated with vehicle, carbenoxolone (100 mg/kg) or menthol (50 mg/kg) and then treated with ethanol to induce gastric ulcers. After euthanasia, stomach samples were prepared for histological slides and biochemical analyses. Immunohistochemical analyses of the cytoprotective and anti-apoptotic heat-shock protein-70 (HSP-70) and the apoptotic Bax protein were performed. The neutrophils were manually counted. The activity of the myeloperoxidase (MPO) was measured. To determine the level of antioxidant functions, the levels of glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and superoxide dismutase (SOD) were measured using ELISA. The levels of the pro-inflammatory cytokines tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6) and the anti-inflammatory cytokine interleukin-10 (IL-10) were assessed using ELISA kits. The menthol treated group presented 92% gastroprotection compared to the vehicle-treated group. An increased immunolabeled area was observed for HSP-70, and a decreased immunolabeled area was observed for the Bax protein in the menthol treated group. Menthol treatment induced a decrease in the activity of MPO and SOD, and the protein levels of GSH, GSH-Px and GR were increased. There was also a decrease in the levels of TNF-? and IL-6 and an increase in the level of IL-10. In conclusion, oral treatment with menthol displayed a gastroprotective activity through anti-apoptotic, antixidant and anti-inflammatory mechanisms. PMID:24466200

Rozza, Ariane Leite; Meira de Faria, Felipe; Souza Brito, Alba Regina; Pellizzon, Cláudia Helena

2014-01-01

291

A novel cycle involving fatty acyl-coenzyme A regulates asialoglycoprotein receptor activity in permeable hepatocytes.  

PubMed Central

Asialoglycoprotein receptors (ASGP-Rs) in permeable rat hepatocytes can be inactivated in the absence of ligand. This cytosol-independent effect is relatively slow (t1/2 approximately 12 min) and is temperature and ATP dependent. Here we show that in the absence of cytosol, the addition of palmitoyl-CoA (Pal-CoA) rapidly (t1/2 < 0.4 min) and quantitatively reactivates the inactivated receptors. Receptor reactivation was half-maximal at approximately 10-12 microM free Pal-CoA at 37 degrees C. Although substantially higher total concentrations were used, much of the added Pal-CoA was cell associated and not free. The effects of Pal-CoA were eliminated by bovine serum albumin at concentrations sufficient to bind all free monomeric fatty acyl-CoA, suggesting that micellar effects are not responsible for the ability to reactivate ASGP-Rs. Also, palmitoyl-carnitine did not substitute for Pal-CoA. The initial ASGP-R inactivation is not affected by treating cells with N-ethylmaleimide or by a KCl wash but is inhibited by sodium orthovanadate or high Ca2+ levels. Myristoyl-CoA (C14) was also able to reactivate inactive ASGP-Rs about as well as Pal-CoA. Fatty acyl-CoAs with chain lengths of C12 (lauroyl) or C18 (steroyl) were < 50% as active. The ligand binding activity of these receptors can subsequently be modulated within minutes by the further addition of ATP or Pal-CoA to achieve additional rounds of ASGP-R inactivation or reactivation, respectively. These in vitro data demonstrate the occurrence of a novel asialoglycoprotein receptor inactivation-reactivation cycle that could regulate receptor activity during endocytosis and receptor recycling.

Weigel, P H; Medh, J D; Oka, J A

1994-01-01

292

Bilirubin mediated oxidative stress involves antioxidant response activation via Nrf2 pathway.  

PubMed

Unconjugated bilirubin (UCB) is responsible for neonatal jaundice and high level of free bilirubin (Bf) can lead to kernicterus. Previous studies suggest that oxidative stress is a critical component of UCB-induced neurotoxicity. The Nrf2 pathway is a powerful sensor for cellular redox state and is activated directly by oxidative stress and/or indirectly by stress response protein kinases. Activated Nrf2 translocates to nucleus, binds to Antioxidant Response Element (ARE), and enhances the up-regulation of cytoprotective genes that mediate cell survival. The aim of the present study was to investigate the role of Nrf2 pathway in cell response to bilirubin mediated oxidative stress in the neuroblastoma SH-SY5Y cell line. Cells exposed to a toxic concentration of UCB (140 nM Bf) showed an increased intracellular ROS levels and enhanced nuclear accumulation of Nrf2 protein. UCB stimulated transcriptional induction of ARE-GFP reporter gene and induced mRNA expression of multiple antioxidant response genes as: xCT, Gly1, ?GCL-m, ?GCL-c, HO-1, NQO1, FTH, ME1, and ATF3. Nrf2 siRNA decreased UCB induced mRNA expression of HO1 (75%), NQO1 (54%), and FTH (40%). The Nrf2-related HO-1 induction was reduced to 60% in cells pre-treated with antioxidant (NAC) or specific signaling pathway inhibitors for PKC, P38? and MEK1/2 (80, 40 and 25%, respectively). In conclusion, we demonstrated that SH-SY5Y cells undergo an adaptive response against UCB-mediated oxidative stress by activation of multiple antioxidant response, in part through Nrf2 pathway. PMID:24308969

Qaisiya, Mohammed; Coda Zabetta, Carlos Daniel; Bellarosa, Cristina; Tiribelli, Claudio

2014-03-01

293

CD147 contains different bioactive epitopes involving the regulation of cell adhesion and lymphocyte activation  

Microsoft Academic Search

CD147 is a leukocyte surface molecule which belongs to the immunoglobulin superfamily. It is broadly expressed on various cell types and is a lymphocyte activation-associated molecule. In order to study the function of CD147, five CD147 monoclonal antibodies (mAbs) were generated: M6-2F9; M6-1D4; M6-1F3; M6-1B9; and M6-1E9. Biochemical characterizations and cross-blocking experiments indicated that M6-1B9 and M6-1E9 recognize the same

Sawitree Chiampanichayakul; Pakorn Peng-in; Panida Khunkaewla; Hannes Stockinger; Watchara Kasinrerk

2006-01-01

294

Regulation of Human CYP2C9 Expression by Electrophilic Stress Involves Activator Protein 1 Activation and DNA Looping.  

PubMed

Cytochrome P450 (CYP)2C9 and CYP2C19 are important human enzymes that metabolize therapeutic drugs, environmental chemicals, and physiologically important endogenous compounds. Initial studies using primary human hepatocytes showed induction of both the CYP2C9 and CYP2C19 genes by tert-butylhydroquinone (tBHQ). As a pro-oxidant, tBHQ regulates the expression of cytoprotective genes by activation of redox-sensing transcription factors, such as the nuclear factor E2-related factor 2 (Nrf2) and members of the activator protein 1 (AP-1) family of proteins. The promoter region of CYP2C9 contains two putative AP-1 sites (TGAGTCA) at positions -2201 and -1930, which are also highly conserved in CYP2C19. The CYP2C9 promoter is activated by ectopic expression of cFos and JunD, whereas Nrf2 had no effect. Using specific kinase inhibitors for mitogen-activated protein kinase, we showed that extracellular signal-regulated kinase and Jun N-terminal kinase are essential for tBHQ-induced expression of CYP2C9. Electrophoretic mobility shift assays demonstrate that cFos distinctly interacts with the distal AP-1 site and JunD with the proximal site. Because cFos regulates target genes as heterodimers with Jun proteins, we hypothesized that DNA looping might be required to bring the distal and proximal AP-1 sites together to activate the CYP2C9 promoter. Chromosome conformation capture analyses confirmed the formation of a DNA loop in the CYP2C9 promoter, possibly allowing interaction between cFos at the distal site and JunD at the proximal site to activate CYP2C9 transcription in response to electrophiles. These results indicate that oxidative stress generated by exposure to electrophilic xenobiotics and metabolites induces the expression of CYP2C9 and CYP2C19 in human hepatocytes. PMID:24830941

Makia, Ngome L; Surapureddi, Sailesh; Monostory, Katalin; Prough, Russell A; Goldstein, Joyce A

2014-08-01

295

Erucylphosphocholine-induced apoptosis in chemoresistant glioblastoma cell lines: involvement of caspase activation and mitochondrial alterations.  

PubMed

Intrinsic chemoresistance constitutes a major problem in the therapy of malignant gliomas. In vitro experiments with four astrocytoma/glioblastoma (AC/GBM) cell lines revealed that the chemoresistance of two cell lines, A172 and T98G, to cisplatin and etoposide was due to resistance to drug-induced apoptosis. In contrast, all the AC/GBM cell lines tested were sensitive to treatment with the lipophilic ether lipid erucylphosphocholine, ErPC. ErPC-induced apoptosis was independent of wild-type p53-signaling and triggering of the CD95/CD95 ligand (CD95L) system. Inhibition of protein and RNA synthesis by cycloheximide and actinomycin D did not abrogate ErPC-induced apoptosis. However, expression of members of the bcl-2 protein family was modulated during ErPC treatment. Activation of caspase 3 and mitochondrial alterations were central to ErPC-induced apoptosis. We conclude that ErPC-induced activation of the mitochondrial pathway enables cell death in the chemoresistant AC/GBM cells. PMID:11848499

Jendrossek, V; Kugler, W; Erdlenbruch, B; Eibl, H; Lang, F; Lakomek, M

2001-01-01

296

Anti-diabetic activity of embelin: involvement of cellular inflammatory mediators, oxidative stress and other biomarkers.  

PubMed

Embelin (benzoquinone), an active constituent of methanolic extracts of the fruit of Embelia basal (Myrsinaceae), was studied in high fat diet (HFD)+streptozotocin (STZ) diabetic rats. Treatment of embelin (25 and 50 mg/kg/day, p.o.) for 3 weeks to HFD+STZ diabetic rats elicited insignificant increase in body weight, reduced the elevated plasma glucose, glycosylated haemoglobin and pro-inflammatory mediators (interleukin 6 and tumour necrosis factor ?) significantly. Furthermore, embelin treatment at both the doses significantly decreased the elevated malondialdehyde, restored depleted glutathione, antioxidant enzymes, superoxide dismutase and catalase in liver. The increased lipid profiles in HFD+STZ diabetic rats were also reduced by embelin treatment significantly. Embelin treatment to HFD+STZ diabetic rats also improved the altered histoarchitecture of ?-islets of pancreas and hepatocytes. The embelin effect on progression of type 2 diabetes mellitus in rats appears to be through the inhibition of intracellular pro-inflammatory mediators, lowering of lipid profile and amelioration of oxidative stress. Considering the pharmacological activity profile of embelin, it is suggested that embelin be a useful diabetic modulator or adjuvant along with clinically effective anti-diabetic drugs in the treatment of type 2 diabetes mellitus and needs to be clinically evaluated on human subjects. PMID:23597490

Naik, Suresh R; Niture, Netaji T; Ansari, Ansar A; Shah, Priyank D

2013-07-15

297

The involvement of 5-lipoxygenase activating protein in anxiety-like behavior  

PubMed Central

The 5-lipoxygenase is an enzyme widely expressed in the central nervous system, where its activity is dependent on the presence the 5-lipoxygenase activating protein (FLAP) for the formation of leukotrienes, potent bioactive lipid mediators. Emerging evidence has shown that the FLAP/leukotriene pathway may play a role in neuropsychiatric disease contexts. In this study we investigated whether genetic deficiency of FLAP (FLAPKO) modulated some behavioral aspects in mice, and if this effect was age-dependent. While we observed that FLAPKO mice at 3 and 6 months of age did not different from wild type animals in the elevated plus maze, at 12 months of age they manifested a significant increase in the anxiety-like behavior. By contrast, we observed no differences between FLAPKO mice and their controls at any of the three ages considered when they were tested for working memory in the Y maze paradigm. Additionally, while we found that cFOS protein and message levels were reduced in the brains of animals lacking FLAP, no changes for other transcription factors were detected. Taken together our findings suggest a novel role for FLAP in the pathogenesis of anxiety-like behavior. Future studies of FLAP neurobiology may be attractive for development of anxiolytic therapeutics.

Joshi, Yash B.; Pratico, Domenico

2013-01-01

298

Tumor cell alpha- N-acetylgalactosaminidase activity and its involvement in GcMAF-related macrophage activation  

Microsoft Academic Search

Alpha-N-acetyl galactosaminidase (alpha-NaGalase) has been reported to accumulate in serum of cancer patients and be responsible for deglycosylation of Gc protein, which is a precursor of GcMAF-mediated macrophage activation cascade, finally leading to immunosuppression in advanced cancer patients. We studied the biochemical characterization of alpha-NaGalase from several human tumor cell lines. We also examined its effect on the potency of

Saharuddin B Mohamad; Hideko Nagasawa; Yoshihiro Uto; Hitoshi Hori

2002-01-01

299

Evidence for dopaminergic and opioid involvement in the regulation of locomotor activity in the land crab Gecarcinus lateralis.  

PubMed

1. Computerized analysis of the crabs locomotor behavior revealed an initial increase in activity followed by a gradual decrease over a 12 min observation period. 2. Dopamine, in a dose-dependent manner, inhibits locomotor activity. The effect can be antagonized with the dopamine antagonist, haloperidol. This suggests that dopaminergic influences are involved with locomotor mechanisms. 3. FK 33,824, a stable opioid analog, significantly enhances the initial excitatory locomotor activity. Naloxone, a potent opiate antagonist, can block the excitatory action induced by FK 33 824. This suggests the presence of an opioid modulation mechanism in the regulation of locomotor activity. 4. Concomitant administration of the various agents results in the behavioral characteristics of the agonist appearing when the appropriate antagonist is not present. Thus, administration of dopamine + FK 33,824 + haloperidol results in enhanced locomotor activity. 5. Concomitant dopamine and FK 33,824 administration results in enhanced locomotor activity. This suggests that the opioid mechanism is closer to the last step in affecting the organism's locomotion or in initiating activity. PMID:2904877

Martinez, E A; Murray, M; Leung, M K; Stefano, G B

1988-01-01

300

Ncb2 Is Involved in Activated Transcription of CDR1 in Azole-Resistant Clinical Isolates of Candida albicans?†  

PubMed Central

We recently demonstrated that CDR1 overexpression in azole-resistant isolates of Candida albicans is due to its enhanced transcriptional activation and increased mRNA stability. In this study, we provide the first evidence of transcriptional regulation of CDR1 by Ncb2, the ? subunit of NC2, a heterodimeric regulator of transcription. Conditional NCB2 null mutants displayed decreased susceptibility toward azole and an enhanced transcription of CDR1. Interestingly, Ncb2 associated with the CDR1 promoter under both repression and activation; however, an increase in recruitment was observed under both transient and constitutive activation states. By chromatin immunoprecipitation (ChIP) assay, we showed the preferential recruitment of Ncb2 to the core TATA region under activation (azole-resistant isolate), while under repression (azole-susceptible isolate) it was present at the TATA upstream region. Further, ChIP analysis revealed that Ncb2 binding was not restricted to the CDR1 gene; instead, it was observed on the promoters of genes coregulated with CDR1 by the transcription activator Tac1. The tac1? null mutants, which fail to show the drug-induced transient activation of CDR1, also showed no increase in Ncb2 recruitment at the promoter. Taken together, our results show that Ncb2, in conjunction with Tac1, is involved in the transcriptional activation of CDR1, opening up new therapeutic possibilities to combat multidrug resistance (MDR) in C. albicans.

Shukla, Shipra; Yadav, Vipin; Mukhopadhyay, Gauranga; Prasad, Rajendra

2011-01-01

301

The endocannabinoid anandamide induces apoptosis of rat decidual cells through a mechanism involving ceramide synthesis and p38 MAPK activation.  

PubMed

Anandamide (AEA) belongs to an endogenous family of lipid messengers, called endocannabinoids (ECs), which exert pharmacological effects by binding to selective membrane receptors, the CB1 and CB2 receptors. Increasing evidence suggests that AEA is involved in the regulation of a variety of cell signalling pathways both in experimental models and humans. We have previously demonstrated that ECs machinery operates in decidual cells and found that AEA, the principal EC, induced apoptosis in decidual cells through CB1. Here, we investigated in rat primary decidual cells the signal transduction pathways activated upon AEA binding to CB1. We found that AEA induces a significant increase in the level of intracellular ceramide. These effects were reversed by inhibiting CB1 receptor activation with AM251. The ceramide analogue, C6-ceramide, induced a decrease in decidual cell viability and of p38 MAPK phosphorylation. Additionally, the pharmacologic inhibition of de novo ceramide biosynthesis with L-cycloserine and fumonisin B reduced the AEA-effects on cell viability and p38 MAPK phosphorylation. Furthermore, AEA and C6-ceramide induced a drop in ??m, an increase in ROS production and caspase-3/-7 activation, effects partially reverted by inhibitors of ceramide synthesis and of p38 MAPK. Taken together, we showed that AEA induces a reduction in decidual cell viability by a mechanism involving CB1 activation, which results in ceramide synthesis de novo and p38 phosphorylation, followed by mitochondrial stress and ROS production, leading to apoptosis. PMID:24048885

Fonseca, B M; Correia-da-Silva, G; Teixeira, N A

2013-12-01

302

Neuroprotective effect of resveratrol against prenatal stress induced cognitive impairment and possible involvement of Na(+), K(+)-ATPase activity.  

PubMed

Resveratrol, an active ingredient of red wine extracts, has been shown to exhibit neuroprotective effects in several experimental models. Hence in the present study, the protective effects of resveratrol on cognitive deficits induced by prenatal stress were evaluated in offspring, and the possible involvement of Na(+), K(+)-ATPase in learning deficits were explored. Pregnant rats were subjected to restraint stress during early or late gestational period. Another set of rats received resveratrol during the entire gestational period along with early or late gestational stress. The study parameters included various behavioral tests like open field test and Morris water maze test. At the end of the behavioral tests (on 40th postnatal day), the offspring were sacrificed, and their brain homogenate was subjected to Na(+), K(+)-ATPase estimation. Early and late gestational stress affected spatial learning and memory and prenatal resveratrol has reversed these cognitive deficits. The Na(+), K(+)-ATPase activity in the offspring brain homogenate was reduced in the late gestational stress group; however prenatal resveratrol treatment has not affected this activity. These data suggest the neuroprotective efficacy of resveratrol against prenatal stress induced cognitive impairment. Though late gestational stress involves Na(+), K(+)-ATPase activity in rat brain homogenate, this would not be the primary cause in prenatal stress-induced cognitive dysfunction. PMID:23044472

Sahu, Sudhanshu Sekhar; Madhyastha, Sampath; Rao, Gayathri M

2013-01-01

303

Using Long-Distance Scientist Involvement to Enhance NASA Volunteer Network Educational Activities  

NASA Astrophysics Data System (ADS)

Since 1999, the NASA/JPL Solar System Ambassadors (SSA) and Solar System Educators (SSEP) programs have used specially-trained volunteers to expand education and public outreach beyond the immediate NASA center regions. Integrating nationwide volunteers in these highly effective programs has helped optimize agency funding set aside for education. Since these volunteers were trained by NASA scientists and engineers, they acted as "stand-ins" for the mission team members in communities across the country. Through the efforts of these enthusiastic volunteers, students gained an increased awareness of NASA's space exploration missions through Solar System Ambassador classroom visits, and teachers across the country became familiarized with NASA's STEM (Science, Technology, Engineering and Mathematics) educational materials through Solar System Educator workshops; however the scientist was still distant. In 2003, NASA started the Digital Learning Network (DLN) to bring scientists into the classroom via videoconferencing. The first equipment was expensive and only schools that could afford the expenditure were able to benefit; however, recent advancements in software allow classrooms to connect to the DLN via personal computers and an internet connection. Through collaboration with the DLN at NASA's Jet Propulsion Laboratory and the Goddard Spaceflight Center, Solar System Ambassadors and Solar System Educators in remote parts of the country are able to bring scientists into their classroom visits or workshops as guest speakers. The goals of this collaboration are to provide special elements to the volunteers' event, allow scientists opportunities for education involvement with minimal effort, acquaint teachers with DLN services and enrich student's classroom learning experience.;

Ferrari, K.

2012-12-01

304

Characterization of streptococcal platelet-activating factor acetylhydrolase variants that are involved in innate immune evasion.  

PubMed

Human pathogen group A streptococcus (GAS) has developed mechanisms to subvert innate immunity. We recently reported that the secreted esterase produced by serotype M1 GAS (SsE(M1)) reduces neutrophil recruitment by targeting platelet-activating factor (PAF). SsE(M1) and SsE produced by serotype M28 GAS (SsE(M28)) have a 37% sequence difference. This study aims at determining whether SsE(M28) is also a PAF acetylhydrolase and participates in innate immune evasion. We also examined whether SsE evolved to target PAF by characterizing the PAF acetylhydrolase (PAF-AH) activity and substrate specificity of SsE(M1), SsE(M28), SeE, the SsE homologue in Streptococcus equi, and human plasma PAF-AH (hpPAF-AH). PAF incubated with SsE(M28) or SeE was converted into lyso-PAF. SsE(M1) and SsE(M28) had kcat values of 373 s(-1) and 467 s(-1), respectively, that were ? 30-fold greater than that of hpPAF-AH (12 s(-1)). The comparison of SsE(M1), SsE(M28), and hpPAF-AH in kcat and Km in hydrolyzing triglycerides, acetyl esters, and PAF indicates that the SsE proteins are more potent hydrolases against PAF and have high affinity for PAF. SsE(M28) possesses much lower esterase activities against triglycerides and other esters than SsE(M1) but have similar potency with SsE(M1) in PAF hydrolysis. Deletion of sse(M28) in a covS deletion mutant of GAS increased neutrophil recruitment and reduced skin infection, whereas in trans expression of SsE(M28) in GAS reduced neutrophil infiltration and increased skin invasion in subcutaneous infection of mice. These results suggest that the SsE proteins evolved to target PAF for enhancing innate immune evasion and skin invasion. PMID:23774595

Liu, Guanghui; Liu, Mengyao; Xie, Gang; Lei, Benfang

2013-09-01

305

PACAP-induced ERK activation in HEK cells expressing PAC1 receptors involves both receptor internalization and PKC signaling.  

PubMed

The pituitary adenylate cyclase-activating polypeptide (PACAP)-selective PAC1 receptor (Adcyap1r1) is a G protein-coupled receptor (GPCR) that activates adenylyl cyclase and PLC. Similar to many other GPCRs, our previous studies showed that the PAC1 receptor is internalized after ligand binding to form signaling endosomes, which recruit additional second messenger pathways. Using a human embryonic kidney (HEK 293) PAC1Hop1-EGFP receptor cell line, we have examined how different PAC1 receptor signaling mechanisms contribute to MEK/ERK activation. Unlike PAC1 receptor-stimulated adenylyl cyclase/cAMP production in the plasma membrane, PACAP-mediated ERK phosphorylation was partly dependent on receptor internalization, as determined by treatment with pharmacological inhibitors of endocytosis or temperature reduction, which also suppressed receptor internalization. Stimulation of cAMP generation by forskolin or exposure to the cell-permeable cAMP analogs 8-bromo-cAMP and dibutyryl cAMP had minimal effects on ERK phosphorylation in this system. The ability of reduced temperature (24°C) to consistently suppress ERK activation to a greater extent than the endocytosis inhibitors Pitstop 2 and dynasore indicated that other mechanisms, in addition to PAC1 internalization/endosome activation, were involved. Inhibition of PAC1 receptor-stimulated PLC/diacylglycerol/PKC signaling by bisindoylmaleimide I also attenuated ERK phosphorylation, and direct PKC activation with phorbol ester increased ERK phosphorylation in a temperature-dependent manner. Inhibition of PAC1 receptor endocytosis and PKC activation completely blocked PACAP-stimulated ERK activation. PACAP augmented phosphorylated ERK staining uniformly over the cytoplasm and nucleus, and PKC signaling facilitated nuclear phosphorylated ERK translocation. In sum, our results show that PACAP/PAC1 receptor endocytosis and PLC/diacylglycerol/PKC activation represent two complementary mechanisms contributing to PACAP-induced ERK activation. PMID:24696141

May, Victor; Buttolph, Thomas R; Girard, Beatrice M; Clason, Todd A; Parsons, Rodney L

2014-06-01

306

Involvement of P2Y receptors in myocardial contractile activity of rats during postnatal ontogeny.  

PubMed

We studied the effect of uridine 5'-triphosphate in concentrations of 10(-10)-10(-6) M on myocardial contractile activity in 7-100-day-old rats. Analysis of isometric contraction of myocardial strips showed that uridine 5'-triphosphate reduced the strength of myocardial contraction in rats of all age groups. In 21- and 100-day-old rat pups, exogenous uridine 5'-triphosphate produced a stronger inhibitory effect than in 7-day-old animals. The negative inotropic effect of UTP was abolished under conditions of P2Y(4) purinoceptor blockade with reagent blue-2. These data indicate that the effect of UTP on the myocardium is realized via P2Y(4) purinoceptors. PMID:22803161

Anikina, T A; Anisimova, I N; Sitdikov, F G

2012-04-01

307

Complexin Activates and Clamps SNAREpins by a Common Mechanism Involving an Intermediate Energetic State  

PubMed Central

The core mechanism of intracellular vesicle fusion consists of SNAREpin zippering between vesicular and target membranes. Recent studies indicate that the same SNARE-binding protein, Complexin (CPX), can act either as a facilitator or as an inhibitor of membrane fusion, giving rise to a major controversy. Here, we employ energetic measurements using the Surface Forces Apparatus which reveal that CPX acts sequentially on assembling SNAREpins, first facilitating zippering by nearly doubling the distance at which v- and t-SNAREs can engage, and then by clamping them into a half-zippered fusion-incompetent state. Specifically, we find that the central helix of CPX allows SNAREs to form this intermediate energetic state at 9–15 nm, but not when the bilayers are closer than 9 nm. Stabilizing the activated-clamped state at separations < 9 nm requires the accessory helix of CPX, which prevents membrane-proximal assembly of SNAREpins.

Li, Feng; Pincet, Frederic; Perez, Eric; Giraudo, Claudio G.; Tareste, David; Rothman, James E.

2013-01-01

308

Complexin activates and clamps SNAREpins by a common mechanism involving an intermediate energetic state.  

PubMed

The core mechanism of intracellular vesicle fusion consists of SNAREpin zippering between vesicular and target membranes. Recent studies indicate that the same SNARE-binding protein, complexin (CPX), can act either as a facilitator or as an inhibitor of membrane fusion, constituting a controversial dilemma. Here we take energetic measurements with the surface force apparatus that reveal that CPX acts sequentially on assembling SNAREpins, first facilitating zippering by nearly doubling the distance at which v- and t-SNAREs can engage and then clamping them into a half-zippered fusion-incompetent state. Specifically, we find that the central helix of CPX allows SNAREs to form this intermediate energetic state at 9-15 nm but not when the bilayers are closer than 9 nm. Stabilizing the activated-clamped state at separations of less than 9 nm requires the accessory helix of CPX, which prevents membrane-proximal assembly of SNAREpins. PMID:21785413

Li, Feng; Pincet, Frédéric; Perez, Eric; Giraudo, Claudio G; Tareste, David; Rothman, James E

2011-08-01

309

In vitro activity of secnidazole against Atopobium vaginae, an anaerobic pathogen involved in bacterial vaginosis.  

PubMed

Bacterial vaginosis is a polymicrobial syndrome. The most important marker for bacterial vaginosis is the presence of Gardnerella vaginalis and Atopobium vaginae. In this study, the in vitro susceptibilities to metronidazole and secnidazole of 16 strains of A. vaginae were tested with the agar dilution method. We observed an MIC range for metronidazole of 4-64 mg/L (MIC(50), 8 mg/L; MIC(90), 32 mg/L) and an MIC range for secnidazole of 4-128 mg/L (MIC(50), 16 mg/L; MIC(90), 64 mg/L). According to these findings, we can conclude that the activity of secnidazole is similar to that of metronidazole. PMID:19548924

De Backer, E; Dubreuil, L; Brauman, M; Acar, J; Vaneechoutte, M

2010-05-01

310

DOE Technical Standards List. Directory of DOE and contractor personnel involved in non-government standards activities  

SciTech Connect

This is a periodic report on the level of agency participation in non-Government standards activities. This technical standards list is intended to assist US Department of Energy (DOE) management and other personnel involved in the DOE technical Standards Program by identifying those participating individuals. The body of this document contains a listing of DOE employees and DOE contractors who have submitted a Record of Non-Government Standards Activity. Additional names were added from rosters supplied by non-Government standards bodies. Appendices to this document are provided to list the information by parent employment organization, by non-Government standards activity, and by the proper names of the non-Government standards organizations and committees.

NONE

1997-06-01

311

Fnr is involved in oxygen control of Herbaspirillum seropedicae N-truncated NifA protein activity in Escherichia coli.  

PubMed

Herbaspirillum seropedicae is an endophytic diazotroph belonging to the beta-subclass of the class Proteobacteria, which colonizes many members of the Gramineae. The activity of the NifA protein, a transcriptional activator of nif genes in H. seropedicae, is controlled by ammonium ions through its N-terminal domain and by oxygen through mechanisms that are not well understood. Here we report that the NifA protein of H. seropedicae is inactive and more susceptible to degradation in an fnr Escherichia coli background. Both effects correlate with oxygen exposure and iron deprivation. Our results suggest that the oxygen sensitivity and iron requirement for H. seropedicae NifA activity involve the Fnr protein. PMID:12620839

Monteiro, Rose A; de Souza, Emanuel M; Yates, M Geoffrey; Pedrosa, Fabio O; Chubatsu, Leda S

2003-03-01

312

Activity-dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen  

PubMed Central

The molecular basis of short-day–induced growth cessation and dormancy in the meristems of perennial plants (e.g., forest trees growing in temperate and high-latitude regions) is poorly understood. Using global transcript profiling, we show distinct stage-specific alterations in auxin responsiveness of the transcriptome in the stem tissues during short-day–induced growth cessation and both the transition to and establishment of dormancy in the cambial meristem of hybrid aspen trees. This stage-specific modulation of auxin signaling appears to be controlled via distinct mechanisms. Whereas the induction of growth cessation in the cambium could involve induction of repressor auxin response factors (ARFs) and down-regulation of activator ARFs, dormancy is associated with perturbation of the activity of the SKP-Cullin-F-boxTIR (SCFTIR) complex, leading to potential stabilization of repressor auxin (AUX)/indole-3-acetic acid (IAA) proteins. Although the role of hormones, such as abscisic acid (ABA) and gibberellic acid (GA), in growth cessation and dormancy is well established, our data now implicate auxin in this process. Importantly, in contrast to most developmental processes in which regulation by auxin involves changes in cellular auxin contents, day-length–regulated induction of cambial growth cessation and dormancy involves changes in auxin responses rather than auxin content.

Baba, Kyoko; Karlberg, Anna; Schmidt, Julien; Schrader, Jarmo; Hvidsten, Torgeir R.; Bako, Laszlo; Bhalerao, Rishikesh P.

2011-01-01

313

The mitogen-activated protein kinase p38 is involved in insect defense against Cry toxins from Bacillus thuringiensis  

PubMed Central

The insecticidal Cry toxins are pore-forming toxins produced by the bacteria Bacillus thuringiensis that disrupt insect-midgut cells. In this work we analyzed the response of two different insect orders, the Lepidopteran Manduca sexta and Dipteran Aedes aegypti to highly specific Cry toxins, Cry1Ab and Cry11Aa, respectively. One pathway activated in different organisms in response to a variety of pore forming toxins is the mitogen activated protein kinase p38 pathway (MAPK p38) that activates a complex defense response. We analyzed the MAPK p38 activation by immunodetection of its phosphorylated isoform, and the induction of p38 by RT-PCR, real time-PCR quantitative assays and immunodection. We show that MAPK p38 is activated at postraductional level after Cry toxin intoxication in both insect orders. We detected the p38 induction at the transcriptional and traductional level, and observed a different response. In these three levels, we found that both insects respond to Cry toxin action but M sexta responses more strongly than A. aegypti. Gene silencing of MAPK p38 in vivo, resulted in both insect species becoming hypersensitive to Cry toxin action, suggesting that the MAPK p38 pathway is involved in insect defense against Bt Cry toxins. This finding may have biotechnological applications for enhancing the activity of some Bt Cry toxins against specific insect pests.

Cancino-Rodezno, Angeles; Alexander, Cynthia; Villasenor, Roberto; Pacheco, Sabino; Porta, Helena; Pauchet, Yannick; Soberon, Mario; Gill, Sarjeet S.; Bravo, Alejandra

2010-01-01

314

PhosphoTyrosyl phosphatase activator of Plasmodium falciparum: identification of its residues involved in binding to and activation of PP2A.  

PubMed

In Plasmodium falciparum (Pf), the causative agent of the deadliest form of malaria, a tight regulation of phosphatase activity is crucial for the development of the parasite. In this study, we have identified and characterized PfPTPA homologous to PhosphoTyrosyl Phosphatase Activator, an activator of protein phosphatase 2A which is a major phosphatase involved in many biological processes in eukaryotic cells. The PfPTPA sequence analysis revealed that five out of six amino acids involved in interaction with PP2A in human are conserved in P. falciparum. Localization studies showed that PfPTPA and PfPP2A are present in the same compartment of blood stage parasites, suggesting a possible interaction of both proteins. In vitro binding and functional studies revealed that PfPTPA binds to and activates PP2A. Mutation studies showed that three residues (V(283), G(292) and M(296)) of PfPTPA are indispensable for the interaction and that the G(292) residue is essential for its activity. In P. falciparum, genetic studies suggested the essentiality of PfPTPA for the completion of intraerythrocytic parasite lifecycle. Using Xenopus oocytes, we showed that PfPTPA blocked the G2/M transition. Taken together, our data suggest that PfPTPA could play a role in the regulation of the P. falciparum cell cycle through its PfPP2A regulatory activity. PMID:24521882

Vandomme, Audrey; Fréville, Aline; Cailliau, Katia; Kalamou, Hadidjatou; Bodart, Jean-François; Khalife, Jamal; Pierrot, Christine

2014-01-01

315

Adrenergic receptor activation involves ATP release and feedback through purinergic receptors  

PubMed Central

Formyl peptide receptor-induced chemotaxis of neutrophils depends on the release of ATP and autocrine feedback through purinergic receptors. Here, we show that adrenergic receptor signaling requires similar purinergic feedback mechanisms. Real-time RT-PCR analysis revealed that human embryonic kidney (HEK)-293 cells express several subtypes of adrenergic (?1-, ?2-, and ?-receptors), adenosine (P1), and nucleotide receptors (P2). Stimulation of Gq-coupled ?1-receptors caused release of cellular ATP and MAPK activation, which was blocked by inhibiting P2 receptors with suramin. Stimulation of Gi-coupled ?2-receptors induced weak ATP release, while Gs-coupled ?-receptors caused accumulation of extracellular ADP and adenosine. ?-Receptors triggered intracellular cAMP signaling, which was blocked by scavenging extracellular adenosine with adenosine deaminase or by inhibiting A2a adenosine receptors with SCH58261. These findings suggest that adrenergic receptors require purinergic receptors to elicit downstream signaling responses in HEK-293 cells. We evaluated the physiological relevance of these findings using mouse aorta tissue rings. Stimulation of ?1-receptors induced ATP release and tissue contraction, which was reduced by removing extracellular ATP with apyrase or in the absence of P2Y2 receptors in aorta rings from P2Y2 receptor knockout mice. We conclude that, like formyl peptide receptors, adrenergic receptors require purinergic feedback mechanisms to control complex physiological processes such as smooth muscle contraction and regulation of vascular tone.

Sumi, Yuka; Woehrle, Tobias; Chen, Yu; Yao, Yongli; Li, Andrew

2010-01-01

316

Tumour induction by activated abl involves tyrosine phosphorylation of the product of the cbl oncogene.  

PubMed Central

v-cbl is the transforming gene of a murine retrovirus which induces pre-B cell lymphomas and myelogenous leukaemias. It encodes 40 kDa of a gag fusion protein which is localized in the cytoplasm and nucleus of infected cells. The c-cbl oncogene encodes a 120 kDa cytoplasmic protein and its overexpression is not associated with tumorigenesis. The c-cbl sequence has shown that v-cbl was generated by a truncation that removed 60% of the C-terminus. In this study, we carried out experiments to identify the position within cbl where the transition occurs between non-tumorigenic and tumorigenic forms. These experiments focused attention on a region of 17 amino acids which is deleted from cbl in the 70Z/3 pre-B lymphoma due to a splice acceptor site mutation. This mutation activates cbl's tumorigenic potential and induces its tyrosine phosphorylation. We also show that the expression of the v-abl and bcr-abl oncogenes results in the induction of cbl tyrosine phosphorylation, and that abl and cbl associate in vivo. These findings demonstrate that tyrosine-phosphorylated cbl promotes tumorigenesis and that cbl is a downstream target of the bcr-abl and v-abl kinases. Images

Andoniou, C E; Thien, C B; Langdon, W Y

1994-01-01

317

Biodegradation of ivory (natural apatite): possible involvement of fungal activity in biodeterioration of the Lewis Chessmen.  

PubMed

Fungal biodeterioration of ivory was investigated with in vitro inoculation of samples obtained from boar and walrus tusks with the fungi Aspergillus niger and Serpula himantioides, species of known geoactive abilities. A combination of light and scanning electron microscopy together with associated analytical techniques was used to characterize fungal interactions with the ivory, including changes in ivory composition, dissolution and tunnelling, and the formation of new biominerals. The research was aimed at providing further understanding of the potential roles of fungi in the colonization and deterioration of ivory in terrestrial environments, but also contributes to our knowledge regarding the possible origins of the surface damage observed on early medieval sculptures made largely from walrus tusks, referred to as 'the Lewis hoard of gaming pieces', that were presumably produced for playing chess. The experiments have shown that the possibility of damage to ivory being caused by fungi is realistic. Scanning electron microscopy revealed penetration of fungal hyphae within cracks in the walrus tusk that showed also widespread tunnelling by fungal hyphae as well as 'fungal footprints' where the surface was etched as a consequence of mycelial colonization. Similar phenomena were observed with boar tusk ivory, while production of metabolites could lead to complete dissolution of the sample. Colonization of ivory and/or exposure to fungal activity lead to extensive secondary biomineral formation, and this was identified as calcium oxalate, mainly as the monohydrate, whewellite. PMID:23157656

Pinzari, Flavia; Tate, James; Bicchieri, Marina; Rhee, Young Joon; Gadd, Geoffrey Michael

2013-04-01

318

Involvement of HIF-1? activation in the doxorubicin resistance of human osteosarcoma cells.  

PubMed

Osteosarcoma is the most common primary bone cancer in children and adolescents. Despite aggressive treatment regimens, survival outcomes remain unsatisfactory, particularly in patients with metastatic and/or recurrent disease. Unfortunately, treatment failure is commonly due to the development of chemoresistance, for which the underlying molecular mechanisms remain unclear. The aim of the present study was to investigate the role of hypoxia-inducible factor 1? (HIF?1?) and its signalling pathways as mediators of drug-resistance in human osteosarcoma. Toward this aim, we established two osteosarcoma cell lines selected for resistance to doxorubicin, a drug of choice in the treatment of this tumour. Our results showed that the multidrug resistance (MDR) phenotype was also mediated by HIF-1?, the most important regulator of cell adaptation to hypoxia. Our data showed that this transcription factor promoted the outward transport of intracellular doxorubicin by activating the P-glycoprotein (P-gp) expression in osteosarcoma cells maintained in normoxic conditions. In addition, it hindered doxorubicin-induced apoptosis by regulating the expression of c-Myc and p21. Finally, we observed that the doxorubicin-resistant cells maintained for 2 months of continuous culture in a drug-free medium, lost their drug-resistance and this effect was associated with the absence of HIF-1? expression. The emerging role of HIF-1? in osteosarcoma biology indicates its use as a valuable therapeutic target. PMID:24840054

Roncuzzi, Laura; Pancotti, Fabia; Baldini, Nicola

2014-07-01

319

Active site residue involvement in monoamine or diamine oxidation catalysed by pea seedling amine oxidase.  

PubMed

The structures of copper amine oxidases from various sources show good similarity, suggesting similar catalytic mechanisms for all members of this enzyme family. However, the optimal substrates for each member differ, depending on the source of the enzyme and its location. The structural factors underlying substrate selectivity still remain to be discovered. With this in view, we examined the kinetic behaviour of pea seedling amine oxidase with cadaverine and hexylamine, the first bearing two, and the second only one, positively charged amino group. The dependence of K(m) and catalytic constant (k(c)) values on pH, ionic strength and temperature indicates that binding of the monoamine is driven by hydrophobic interactions. Instead, binding of the diamine is strongly facilitated by electrostatic factors, controlled by polar side-chains and two titratable residues present in the active site. The position of the docked substrate is also essential for the participation of titratable amino acid residues in the following catalytic steps. A new mechanistic model explaining the substrate-dependent kinetics of the reaction is discussed. PMID:21294844

Di Paolo, Maria Luisa; Lunelli, Michele; Fuxreiter, Monika; Rigo, Adelio; Simon, Istvan; Scarpa, Marina

2011-04-01

320

Attributes of Dental Trauma in a School Population with Active Sports Involvement  

PubMed Central

Purpose Dental trauma has become an important aspect of dental public health. The primary requisite before actively dealing with such problems is to describe the extent, distribution, and variables associated with the specific condition. The purpose of this study was to assess the prevalence and role of socioeconomic status and anatomic risk factors in traumatic dental injuries (TDI) to permanent anterior teeth in 10 to 16 year old Sainik (Army) school, children in India. Methods A cross-sectional study was conducted. Data was collected through a survey form and clinical examination. The permanent anterior teeth of four hundred and forty six male school children were examined for TDI. The socio-economic status, lip coverage and overjet were recorded. Statistical significance for the association between occurrence of TDI and the various risk factors was carried out. Results The prevalence of TDI to permanent anterior teeth was 23.8%. A large number of injuries occurred during participation in sports. Inadequate lip coverage and a large maxillary overjet were identified as important predictors for dental trauma. Conclusion A high prevalence of dental trauma was observed in the study population suggestive of low awareness regarding the cause, effects and prevention of the condition.

Prabhu, Anand; Rao, Arun Prasad; Govindarajan, Mohan; Reddy, Venugopal; Krishnakumar, Ramalingam; Kaliyamoorthy, Sugumaran

2013-01-01

321

Pituitary adenylate cyclase-activating polypeptide is a sympathoadrenal neurotransmitter involved in catecholamine regulation and glucohomeostasis  

PubMed Central

The adrenal gland is important for homeostatic responses to metabolic stress: hypoglycemia stimulates the splanchnic nerve, epinephrine is released from adrenomedullary chromaffin cells, and compensatory glucogenesis ensues. Acetylcholine is the primary neurotransmitter mediating catecholamine secretion from the adrenal medulla. Accumulating evidence suggests that a secretin-related neuropeptide also may function as a transmitter at the adrenomedullary synapse. Costaining with highly specific antibodies against the secretin-related neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) and the vesicular acetylcholine transporter (VAChT) revealed that PACAP is found in nerve terminals at all mouse adrenomedullary cholinergic synapses. Mice with a targeted deletion of the PACAP gene had otherwise normal cholinergic innervation and morphology of the adrenal medulla, normal adrenal catecholamine and blood glucose levels, and an intact initial catecholamine secretory response to insulin-induced hypoglycemia. However, insulin-induced hypoglycemia was more profound and longer-lasting in PACAP knock-outs, and was associated with a dose-related lethality absent in wild-type mice. Failure of PACAP-deficient mice to adequately counterregulate plasma glucose levels could be accounted for by impaired long-term secretion of epinephrine, secondary to a lack of induction of tyrosine hydroxylase, normally occurring after insulin hypoglycemia in wild-type mice, and a consequent depletion of adrenomedullary epinephrine stores. Thus, PACAP is needed to couple epinephrine biosynthesis to secretion during metabolic stress. PACAP appears to function as an “emergency response” cotransmitter in the sympathoadrenal axis, where the primary secretory response is controlled by a classical neurotransmitter but sustained under paraphysiological conditions by a neuropeptide.

Hamelink, Carol; Tjurmina, Olga; Damadzic, Ruslan; Young, W. Scott; Weihe, Eberhard; Lee, Hyeon-Woo; Eiden, Lee E.

2002-01-01

322

A Pathogenic Mechanism in Huntington's Disease Involves Small CAG-Repeated RNAs with Neurotoxic Activity  

PubMed Central

Huntington's disease (HD) is an autosomal dominantly inherited disorder caused by the expansion of CAG repeats in the Huntingtin (HTT) gene. The abnormally extended polyglutamine in the HTT protein encoded by the CAG repeats has toxic effects. Here, we provide evidence to support that the mutant HTT CAG repeats interfere with cell viability at the RNA level. In human neuronal cells, expanded HTT exon-1 mRNA with CAG repeat lengths above the threshold for complete penetrance (40 or greater) induced cell death and increased levels of small CAG-repeated RNAs (sCAGs), of ?21 nucleotides in a Dicer-dependent manner. The severity of the toxic effect of HTT mRNA and sCAG generation correlated with CAG expansion length. Small RNAs obtained from cells expressing mutant HTT and from HD human brains significantly decreased neuronal viability, in an Ago2-dependent mechanism. In both cases, the use of anti-miRs specific for sCAGs efficiently blocked the toxic effect, supporting a key role of sCAGs in HTT-mediated toxicity. Luciferase-reporter assays showed that expanded HTT silences the expression of CTG-containing genes that are down-regulated in HD. These results suggest a possible link between HD and sCAG expression with an aberrant activation of the siRNA/miRNA gene silencing machinery, which may trigger a detrimental response. The identification of the specific cellular processes affected by sCAGs may provide insights into the pathogenic mechanisms underlying HD, offering opportunities to develop new therapeutic approaches.

Banez-Coronel, Monica; Porta, Silvia; Kagerbauer, Birgit; Mateu-Huertas, Elisabet; Pantano, Lorena; Ferrer, Isidre; Guzman, Manuel; Estivill, Xavier; Marti, Eulalia

2012-01-01

323

Impairment of the Intestinal Barrier by Ethanol Involves Enteric Microflora and Mast Cell Activation in Rodents  

PubMed Central

Alcohol hepatic toxicity in heavy drinkers is associated with high endotoxin blood levels and increased intestinal permeability. Because endotoxins can cross damaged mucosa, we investigated the mechanisms through which ethanol impairs the colonic epithelium of rats submitted to acute alcohol intake. Colonic permeability to 51Cr-ethylenediamintetraacetic acid was increased 24 hours after 3.0 g/kg ethanol intake (3.2 ± 0.2% versus 2.2 ± 0.2%) and was associated with significant endotoxemia. Antibiotics and doxantrazole (a mast cell membrane stabilizer) significantly inhibited the effect of ethanol. Two hours after intake, plasma concentrations of ethanol were twofold higher in antibiotic-treated rats than in controls (155.8 ± 9.3 mg/dl versus 75.7 ± 7.6 mg/dl, P < 0.001). Lumenal concentrations of acetaldehyde were markedly increased after ethanol intake (132.6 ± 31.6 ?mol/L versus 20.8 ± 1.4 ?mol/L, P < 0.05) and antibiotics diminished this increase (86.2 ± 10.9 ?mol/L). In colonic samples mounted in Ussing chambers, acetaldehyde but not ethanol increased dextran flux across the mucosa by 54%. Doxantrazole inhibited the effect of acetaldehyde. This study demonstrates that an acute and moderate ethanol intake alters the epithelial barrier through ethanol oxidation into acetaldehyde by the colonic microflora and downstream mast cell activation. Such alterations that remain for longer periods could result in excessive endotoxin passage, which could explain the subsequent endotoxemia frequently observed in patients with alcoholic liver disease.

Ferrier, Laurent; Berard, Florian; Debrauwer, Laurent; Chabo, Chantal; Langella, Philippe; Bueno, Lionel; Fioramonti, Jean

2006-01-01

324

The structure of DesR from Streptomyces venezuelae, a ?-glucosidase involved in macrolide activation  

PubMed Central

Antibiotics have, indeed, altered the course of human history as is evidenced by the increase in human life expectancy since the 1940s. Many of these natural compounds are produced by bacteria that, by necessity, must have efficient self-resistance mechanisms. The methymycin/pikromycin producing species Streptomyces venezuelae, for example, utilizes ?-glucosylation of its macrolide products to neutralize their effects within the confines of the cell. Once released into the environment, these compounds are activated by the removal of the glucose moiety. In S. venezuelae, the enzyme responsible for removal of the sugar from the parent compound is encoded by the desR gene and referred to as DesR. It is a secreted enzyme containing 828 amino acid residues, and it is known to be a retaining glycosidase. Here, we describe the structure of the DesR/d-glucose complex determined to 1.4-Å resolution. The overall architecture of the enzyme can be envisioned in terms of three regions: a catalytic core and two auxiliary domains. The catalytic core harbors the binding platform for the glucose ligand. The first auxiliary domain adopts a “PA14 fold,” whereas the second auxiliary domain contains an immunoglobulin-like fold. Asp 273 and Glu 578 are in the proper orientation to function as the catalytic base and proton donor, respectively, required for catalysis. The overall fold of the core region places DesR into the GH3 glycoside hydrolase family of enzymes. Comparison of the DesR structure with the ?-glucosidase from Kluyveromyces marxianus shows that their PA14 domains assume remarkably different orientations.

Zmudka, Matthew W; Thoden, James B; Holden, Hazel M

2013-01-01

325

Modulation of Pineal Melatonin Synthesis by Glutamate Involves Paracrine Interactions between Pinealocytes and Astrocytes through NF-?B Activation  

PubMed Central

The glutamatergic modulation of melatonin synthesis is well known, along with the importance of astrocytes in mediating glutamatergic signaling in the central nervous system. Pinealocytes and astrocytes are the main cell types in the pineal gland. The objective of this work was to investigate the interactions between astrocytes and pinealocytes as a part of the glutamate inhibitory effect on melatonin synthesis. Rat pinealocytes isolated or in coculture with astrocytes were incubated with glutamate in the presence of norepinephrine, and the melatonin content, was quantified. The expression of glutamate receptors, the intracellular calcium content and the NF-?B activation were analyzed in astrocytes and pinealocytes. TNF-?'s possible mediation of the effect of glutamate was also investigated. The results showed that glutamate's inhibitory effect on melatonin synthesis involves interactions between astrocytes and pinealocytes, possibly through the release of TNF-?. Moreover, the activation of the astrocytic NF-?B seems to be a necessary step. In astrocytes and pinealocytes, AMPA, NMDA, and group I metabotropic glutamate receptors were observed, as well as the intracellular calcium elevation. In conclusion, there is evidence that the modulation of melatonin synthesis by glutamate involves paracrine interactions between pinealocytes and astrocytes through the activation of the astrocytic NF-?B transcription factor and possibly by subsequent TNF-? release.

Atherino, Victoria Fairbanks; Lima, Larissa de Sa; Moutinho, Anderson Augusto; do Amaral, Fernanda Gaspar; Peres, Rafael; Martins de Lima, Thais; Torrao, Andrea da Silva; Cipolla-Neto, Jose; Scavone, Cristoforo; Afeche, Solange Castro

2013-01-01

326

Activating transcription factor 4 is involved in endoplasmic reticulum stress-mediated apoptosis contributing to vascular calcification.  

PubMed

Our previous work reported that endoplasmic reticulum stress (ERS)-mediated apoptosis was activated during vascular calcification (VC). Activating transcription factor 4 (ATF4) is a critical transcription factor in osteoblastogenesis and ERS-induced apoptosis. However, whether ATF4 is involved in ERS-mediated apoptosis contributing to VC remains unclear. In the present study, in vivo VC was induced in rats by administering vitamin D3 plus nicotine. Vascular smooth muscle cell (VSMC) calcification in vitro was induced by incubation in calcifying media containing ?-glycerophosphate and CaCl2. ERS inhibitors taurine or 4-phenylbutyric acid attenuated ERS and VSMC apoptosis in calcified rat arteries, reduced calcification and retarded the VSMC contractile phenotype transforming into an osteoblast-like phenotype in vivo. Inhibition of ERS retarded the VSMC phenotypic transition into an osteoblast-like cell phenotype and reduced VSMC calcification and apoptosis in vitro. Interestingly, ATF4 was activated in calcified aortas and calcified VSMCs in vitro. ATF4 knockdown attenuated ERS-induced apoptosis in calcified VSMCs. ATF4 deficiency blocked VSMC calcification and negatively regulated the osteoblast phenotypic transition of VSMCs in vitro. Our results demonstrate that ATF4 was involved at least in part in the process of ERS-mediated apoptosis contributing to VC. PMID:23686245

Duan, Xiao-Hui; Chang, Jin-Rui; Zhang, Jing; Zhang, Bao-Hong; Li, Yu-Lin; Teng, Xu; Zhu, Yi; Du, Jie; Tang, Chao-Shu; Qi, Yong-Fen

2013-09-01

327

Involvement of SLC17A9-dependent Vesicular Exocytosis in the Mechanism of ATP Release during T Cell Activation  

PubMed Central

Recent reports have shown that T cell receptor (TCR)-dependent ATP release from T cells is involved in production of interleukin-2 (IL-2) through activation of P2 receptors. Stimulation of TCR induces ATP release from T cells through gap junction hemichannels and maxianion channels, at least in part. However, the mechanisms of ATP release from activated T cells are not fully understood. Here, we studied the mechanisms of ATP release during TCR-dependent T cell activation by investigating the effects of various inhibitors on TCR-dependent ATP release from murine T cells. We found that not only anion channel and gap junction hemichannel inhibitors, but also exocytosis inhibitors suppressed the ATP release. These results suggest that ATP release from murine T cells is regulated by various mechanisms, including exocytosis. An inhibitor of exocytosis, bafilomycin A, significantly blocked TCR signaling, such as Ca2+ elevation and IL-2 production. Furthermore, bafilomycin A, ectonucleotidase, and P2Y6 receptor antagonist significantly inhibited production of pro-inflammatory cytokines from external antigen-restimulated splenocytes, indicating that vesicular exocytosis-mediated purinergic signaling has a significant role in TCR-dependent cytokine production. We also detected vesicular ATP in murine T cells and human T lymphoma Jurkat cells, both of which also expressed mRNA of SLC17A9, a vesicular nucleotide transporter. Knockdown of SLC17A9 in Jurkat cells markedly reduced ATP release and cytosolic Ca2+ elevation after TCR stimulation, suggesting involvement of SLC17A9-dependent vesicular exocytosis in ATP release and T cell activation. In conclusion, vesicular exocytosis of ATP appears to play a role in T cell activation and immune responses.

Tokunaga, Akihiro; Tsukimoto, Mitsutoshi; Harada, Hitoshi; Moriyama, Yoshinori; Kojima, Shuji

2010-01-01

328

Contractile activity regulates isoform expression and polysialylation of NCAM in cultured myotubes: involvement of Ca2+ and protein kinase C  

PubMed Central

Muscle development involves a series of complex cell-cell interactions that are mediated, at least in part, by several different cell adhesion molecules. Previous work from this lab showed that the different isoforms of NCAM and its level of polysialylation are developmentally regulated during chick myogenesis in vivo and that this regulation is important for normal muscle development. Using developing chick secondary myotubes grown in culture, we show here that both the polysialylation of NCAM and the developmental switch in isoform expression are regulated by activity and that Ca2+ entry through voltage-gated channels and the subsequent activation of protein kinase C are required for the developmental changes in NCAM isoform synthesis. Specifically, PSA expression was shown to be developmentally regulated with high expression being temporally correlated with the onset of spontaneous contractile activity. Furthermore, blocking contractile activity caused a decrease in PSA expression, while increasing activity with electrical stimulation resulted in its up-regulation. Immunoblot and metabolic labeling studies indicated that dividing myoblasts synthesize primarily 145-kD NCAM, newly formed, spontaneously contracting myotubes synthesize 130-, 145-, and 155-kD NCAM isoforms, while older, more mature myotubes primarily synthesize the glycosylphosphatidylinositol-anchored 130-kD isoform which, in contrast to the other three isoforms, had a high rate of turnover. This developmental switch in NCAM isoform expression could be inhibited with Ca2+ channel blockers and inhibitors of protein kinase C. Taken together, these results suggest that Ca2+ ions and protein kinase C are involved in a second messenger cascade coupling membrane depolarization with transcriptional factors that regulate NCAM isoform synthesis and polysialylation.

1996-01-01

329

MicroRNA-122 Down-Regulation Is Involved in Phenobarbital-Mediated Activation of the Constitutive Androstane Receptor  

PubMed Central

Constitutive androstane receptor (CAR) is a nuclear receptor that regulates the transcription of target genes, including CYP2B and 3A. Phenobarbital activates CAR, at least in part, in an AMP-activated protein kinase (AMPK)-dependent manner. However, the precise mechanisms underlying phenobarbital activation of AMPK are still unclear. In the present study, it was demonstrated that phenobarbital administration to mice decreases hepatic miR-122, a liver-enriched microRNA involved in both hepatic differentiation and function. The time-course change in the phenobarbital-mediated down-regulation of miR-122 was inversely correlated with AMPK activation. Phenobarbital decreased primary miR-122 to approximately 25% of the basal level as early as 1 h and suppressed transactivity of mir-122 promoter in HuH-7 cells, suggesting that the down-regulation occurred at the transcriptional level. AMPK activation by metformin or 5-aminoimidazole-4-carboxamide 1-?-D-ribonucleoside had no evident effect on miR-122 levels. An inhibitory RNA specific for miR-122 increased activated AMPK and CAR-mediated trancactivation of the phenobarbital-responsive enhancer module in HepG2 cells. Conversely, the reporter activity induced by the ectopic CAR was almost completely suppressed by co-transfection with the miR-122 mimic RNA. GFP-tagged CAR was expressed in the cytoplasm in addition to the nucleus in the majority of HuH-7 cells in which miR-122 was highly expressed. Co-transfection of the mimic or the inhibitor RNA for miR-122 further increased or decreased, respectively, the number of cells that expressed GFP-CAR in the cytoplasm. Taken together, these results suggest that phenobarbital-mediated down-regulation of miR-122 is an early and important event in the AMPK-dependent CAR activation and transactivation of its target genes.

Shizu, Ryota; Shindo, Sawako; Yoshida, Takemi; Numazawa, Satoshi

2012-01-01

330

Calcitriol mediates the activity of SGLT1 through an extranuclear initiated mechanism that involves intracellular signaling pathways  

Microsoft Academic Search

The present study explored whether calcitriol plays a role in the regulation of sodium-dependent glucose transporter protein\\u000a 1 (SGLT1) activity. For this purpose, alpha-methyl glucoside (AMG) uptake in stable transfected Chinese hamster ovary (CHO-G6D3)\\u000a cells expressing rabbit SGLT1 (rbSGLT1) was used. The involvement of second messengers, intracellular signaling pathways,\\u000a and pro-inflammatory cytokines were examined using specific inhibitors before incubation with

Carmen Castaneda-Sceppa; Francisco Castaneda

2010-01-01

331

Caspase 3 involves in neuroplasticity, microglial activation and neurogenesis in the mice hippocampus after intracerebral injection of kainic acid  

PubMed Central

Background The roles of caspase 3 on the kainic acid-mediated neurodegeneration, dendritic plasticity alteration, neurogenesis, microglial activation and gliosis are not fully understood. Here, we investigate hippocampal changes using a mouse model that receive a single kainic acid-intracerebral ventricle injection. The effects of caspase 3 inhibition on these changes were detected during a period of 1 to 7 days post kainic acid injection. Result Neurodegeneration was assessed by Fluoro-Jade B staining and neuronal nuclei protein (NeuN) immunostaining. Neurogenesis, gliosis, neuritic plasticity alteration and caspase 3 activation were examined using immunohistochemistry. Dendritic plasticity, cleavvage-dependent activation of calcineurin A and glial fibrillary acidic protein cleavage were analyzed by immunoblotting. We found that kainic acid not only induced neurodegeneration but also arouse several caspase 3-mediated molecular and cellular changes including dendritic plasticity, neurogenesis, and gliosis. The acute caspase 3 activation occurred in pyramidal neurons as well as in hilar interneurons. The delayed caspase 3 activation occurred in astrocytes. The co-injection of caspase 3 inhibitor did not rescue kainic acid-mediated neurodegeneration but seriously and reversibly disturb the structural integrity of axon and dendrite. The kainic acid-induced events include microglia activation, the proliferation of radial glial cells, neurogenesis, and calcineurin A cleavage were significantly inhibited by the co-injection of caspase 3 inhibitor, suggesting the direct involvement of caspase 3 in these events. Alternatively, the kainic acid-mediated astrogliosis is not caspase 3-dependent, although caspase 3 cleavage of glial fibrillary acidic protein occurred. Conclusions Our results provide the first direct evidence of a causal role of caspase 3 activation in the cellular changes during kainic acid-mediated excitotoxicity. These findings may highlight novel pharmacological strategies to arrest disease progression and control seizures that are refractory to classical anticonvulsant treatment.

2013-01-01

332

Mechanisms of chloride in cardiomyocyte anoxia-reoxygenation injury: the involvement of oxidative stress and NF-kappaB activation.  

PubMed

During anoxia/reoxygenation (A/R) injury, intracellular chloride ion concentration ([Cl(-)](i)) homeostasis may play a role in maintaining the normal physiological function of cardiomyocytes. Various chloride transport systems could have influenced the concentration of chloride ion, but what kinds of chloride transport systems could play an important role in cardiomyocytes subjected to A/R injury and its mechanism are unknown. The aim of our study was to clarify the contributions of various chloride transport systems to anoxia/reoxygenation in rat neonatal cardiac myocytes and further to investigate the involved mechanisms. Oxidative stress and redox-sensitive transcription factor (NF-kappaB) activation are believed to play an important role in the A/R injury. To assess whether oxidative stress and NF-kappaB involve [Cl(-)](i) changes resulting in cardiomyocytes injury, the anoxia-reoxygenation (A/R) injury model was successfully established and administered with inhibitors of various chloride transport systems. Administration with Cl(-)-substitution and Cl(-)/HCO(3) (-) exchange inhibitor(SITS) has been shown to produce a protective effect against A/R injury by decreasing [Cl(-)](i) concentration, lipid peroxidation (malondialdehyde (MDA)) levels, and NF-kappaB activity, and by increasing antioxidant enzyme (glutathione peroxidase (GSHPx), superoxide dismutase (SOD), and catalase(CAT)) activity. However, inhibitors for the Cl(-)-channel (9-AC) and Na(+)-K(+)-2Cl(-) co-transporter (bumetanide) had no effects. Our results indicate that Cl(-)/HCO(3) (-) exchange system plays an important role in the cardiocyte A/R injury by influencing [Cl(-)](i) concentration. The protective effects of SITS and Cl(-)-substitution on cardiomyocytes may be due to the attenuation of oxidative stress and inhibition of NF-kappaB activation. PMID:21553261

Liu, D; He, H; Li, G L; Chen, J; Yin, D; Liao, Z P; Tang, L; Huang, Q R; Lai, Z F; He, M

2011-09-01

333

Effect of Specific Elicitors of Cladosporium fulvum on Tomato Suspension Cells : Evidence for the Involvement of Active Oxygen Species.  

PubMed

Intercellular fluid (IF) obtained from tomato (Lycopersicon esculentum L.) leaflets colonized by Cladosporium fulvum Cooke contains specific elicitors that induce necrosis in tomato cultivars resistant to the race of C. fulvum used to produce the IF. The responses of cell-suspension cultures produced from tomato lines near-isogenic for resistance genes Cf 4 and Cf 5 to IF produced from leaves infected by races 4 (virulent on Cf 4 but not Cf 5 plants), 2.4.5, and 2.4.5.9 (both virulent on Cf 4 and Cf 5 plants) were used to investigate the possibility that active oxygen (AO) species were involved in the initial host reaction to these elicitors. Concurrently, the same assays were used to determine if the cell lines retained the elicitor specificity of the original plants. An IF/cell combination that gives an incompatible reaction in leaves (race 4 IF and Cf 5 cells) showed reduced oxygen uptake and increases in malonaldehyde (a product of lipid peroxidation); cytochrome c reducing activity, which was inhibited by superoxide dismutase (SOD) (an assay for superoxide); luminol-dependent chemiluminescence (an assay for several AO species); activity of extracellular peroxidases; and extracellular phenolic compounds. In contrast, compatible combinations (IF from races 2.4.5 or 2.4.5.9 and Cf 4 or Cf 5 cells; race 4 IF and Cf 4 cells) did not exhibit any of these changes. The addition of catalase, SOD, ascorbate (a scavenger of superoxide), mannitol (a scavenger of the hydroxyl radical), KCN, or salicyl hydroxamic acid (both inhibitors of peroxidases) prior to IF treatment reduced the IF-induced increases in malonaldehyde and extracellular phenolics. Catalase was an effective inhibitor of the IF-induced changes in oxygen uptake and cytochrome c reducing activity. These results demonstrate the specificity of the IF-induced cell responses and confirm that AO species are involved in the initial cell response. PMID:16668990

Vera-Estrella, R; Blumwald, E; Higgins, V J

1992-07-01

334

Activation of the ubiquitin-proteasome system against arsenic trioxide cardiotoxicity involves ubiquitin ligase Parkin for mitochondrial homeostasis.  

PubMed

Parkin is an E3 ubiquitin ligase involved in the elimination of damaged mitochondria. Ubiquitination of mitochondrial substrates by Parkin results in proteasomal as well as lysosomal degradation of mitochondria, the latter of which is executed by the autophagy machinery and is called as mitophagy (mitochondrial autophagy). The aim of this study is to examine the possible role of Parkin against cardiotoxicity elicited by arsenic trioxide (ATO) exposure in HL-1 mouse atrial cardiomyocytes. HL-1 cells were administered 1-10?M ATO for up to 24h, and the involvements of apoptosis, and the ubiquitin-proteasome and autophagy-lysosome systems (UPS and ALS) were examined. ATO dose-dependently reduced mitochondrial membrane potentials (??m) in HL-1 cells, indicating that ATO works as a mitochondrial toxin in these cells. Apoptosis was evident in cells exposed to more than 6?M ATO for 24h. Levels of Parkin in mitochondria-rich fractions were increased, suggesting the recruitment of Parkin to mitochondria. Ubiquitination of the voltage-dependent anion channel1 (VDAC1), a substrate of Parkin, was also proved by immunoprecipitation. Accumulation of ubiquitinated proteins including both K48- and K63-lineages was observed in HL-1 cells after ATO exposure, implying an increased demand for proteasomal as well as lysosomal degradation of cellular proteins. Although UPS was activated by ATO as proved by increased proteasomal activity, only slight activation of the ALS marker LC3 was observed, suggesting differential reactions of UPS and ALS to ATO toxicity. The abrogation of UPS by the proteasome inhibitor bortezomib significantly sensitized HL-1 cells to ATO toxicity, showing the contribution of UPS to the maintenance of cellular homeostasis during ATO exposure. Taken together, our results reveal the activation of Parkin as well as UPS during ATO exposure in HL-1 cardiomyocytes, which contributes to the maintenance of mitochondrial as well as cellular homeostasis. PMID:24801902

Watanabe, Mayumi; Funakoshi, Takeshi; Unuma, Kana; Aki, Toshihiko; Uemura, Koichi

2014-08-01

335

Metatranscriptome of an anaerobic benzene-degrading, nitrate-reducing enrichment culture reveals involvement of carboxylation in benzene ring activation.  

PubMed

The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the differential gene expression between the two treatments. Ribosomal and mRNA sequences attributed to a member of the family Peptococcaceae from the order Clostridiales were essentially only detected in the benzene-amended culture samples, implicating this group in the initial catabolism of benzene. Genes similar to each of two subunits of a proposed benzene-carboxylating enzyme were transcribed when the culture was amended with benzene. Anaerobic benzoate degradation genes from strict anaerobes were transcribed only when the culture was amended with benzene. Genes for other benzoate catabolic enzymes and for nitrate respiration were transcribed in both samples, with those attributed to an Azoarcus species being most abundant. These findings indicate that the mineralization of benzene starts with its activation by a strict anaerobe belonging to the Peptococcaceae, involving a carboxylation step to form benzoate. These data confirm the previously hypothesized syntrophic association between a benzene-degrading Peptococcaceae strain and a benzoate-degrading denitrifying Azoarcus strain for the complete catabolism of benzene with nitrate as the terminal electron acceptor. PMID:24795366

Luo, Fei; Gitiafroz, Roya; Devine, Cheryl E; Gong, Yunchen; Hug, Laura A; Raskin, Lutgarde; Edwards, Elizabeth A

2014-07-15

336

Transcription factor AP1 is involved in basal and okadaic acid-stimulated activity of the human PRL promoter.  

PubMed

The tumor promoter, okadaic acid (OA), an inhibitor of protein phosphatases, stimulates the activity of the human PRL (hPRL) proximal promoter. We analyzed in detail the effects of OA on transcription factor binding to elements P1 and P2 of this promoter, sequences known to contain at least one Pit-1 binding site each. OA treatment induces binding of an AP1-related transcription factor to the P1 site. This effect is specific, as protein binding to the P2 site is not altered by the treatment. Specific antibodies were used to confirm that the OA-induced complex is related to AP1 and to show that it contains JunD and c-fos, but not Pit-1. The increase in AP1 binding to P1 and to a canonical AP1 site correlates to an increase in cellular JunD and c-fos content. Transient transfection experiments showed that both AP1 and Pit-1 are involved in the regulation of basal and OA-stimulated promoter activity. Our results demonstrate that a member of the AP1 family, containing JunD and c-fos, can bind to the proximal element P1 within the hPRL promoter. In addition, they show that AP1 is involved in both basal and OA-stimulated expression of the hPRL gene. PMID:9717847

Caccavelli, L; Manfroid, I; Martial, J A; Muller, M

1998-08-01

337

Involvement of A20 in the molecular switch that activates the non-canonical NF-?B pathway.  

PubMed

The non-canonical NF-?B pathway is crucial for the immune system. A critical event in activation of the non-canonical pathway is the attenuation of NF-?B-inducing kinase (NIK) degradation, which is promoted by continuous polyubiquitination of NIK catalyzed by the NIK ubiquitin-ligase complex composed of cellular inhibitor of apoptosis protein 1 and 2 (cIAP1/2), TNF receptor-associated factor 2 (TRAF2), and TRAF3. However, the molecular mechanism of stimulation-dependent NIK stabilization remains poorly understood. Here, we show that A20, a ubiquitin-editing enzyme, promotes efficient activation of the non-canonical pathway independent of its catalytic activity. A20 directly binds to cIAP1 through the seventh zinc finger of A20, resulting in dissociation of the TRAF2/TRAF3 interaction, thereby inactivating the ligase complex to stabilize NIK. Given that A20 negatively regulates the canonical pathway, A20 is likely involved in the molecular switch that promotes the transition from canonical to non-canonical activation for proper control of the immune system. PMID:24008839

Yamaguchi, Noritaka; Oyama, Masaaki; Kozuka-Hata, Hiroko; Inoue, Jun-ichiro

2013-01-01

338

Connexin43 mediates NF-?B signalling activation induced by high glucose in GMCs: involvement of c-Src  

PubMed Central

Background Nuclear factor kappa-B (NF-?B) signalling plays an important role in diabetic nephropathy. Altered expression of connexin43 (Cx43) has been found in kidneys of diabetic animals. The aim of the current study was to investigate the role of Cx43 in the activation of NF-?B induced by high glucose in glomerular mesangial cells (GMCs) and to determine whether c-Src is involved in this process. Results We found that downregulation of Cx43 expression induced by high glucose activated NF-?B in GMCs. Orverexpression of Cx43 attenuated NF-?B p65 nuclear translocation induced by high glucose. High glucose inhibited the interaction between Cx43 and c-Src, and enhanced the interaction between c-Src and I?B-?. PP2, a c-Src inhibitor, also inhibited the tyrosine phosphorylation of I?B-? and NF-?B p65 nuclear translocation induced by high glucose. Furthermore, overexpression of Cx43 or inhibition of c-Src attenuated the upregulation of intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-?1) and fibronectin (FN) expression induced by high glucose. Conclusions In conclusion, downregulation of Cx43 in GMCs induced by high glucose activates c-Src, which in turn promotes interaction between c-Src and I?B-? and contributes to NF-?B activation in GMCs, leading to renal inflammation.

2013-01-01

339

Hemin inhibits NLRP3 inflammasome activation in sepsis-induced acute lung injury, involving heme oxygenase-1.  

PubMed

NLRP3 inflammasome activation contributes to acute lung injury (ALI), accelerating caspase-1 maturation, and resulting in IL-1? and IL-18 over-production. Heme oxygenase-1 (HO-1) plays a protective role in ALI. This study investigated the effect of hemin (a potent HO-1 inducer) on NLRP3 inflammasome in sepsis-induced ALI. The sepsis model of cecal ligation and puncture (CLP) was used in C57BL6 mice. In vivo induction and suppression of HO-1 were performed by pretreatment with hemin and zinc protoporphyrin IX (ZnPP, a HO-1 competitive inhibitor) respectively. CLP triggered significant pulmonary damage, neutrophil infiltration, increased levels of IL-1? and IL-18, and edema formation in the lung. Hemin pretreatment exerted inhibitory effect on lung injury and attenuated IL-1? and IL-18 secretion in serum and lung tissue. In lung tissues, hemin down-regulated mRNA and protein levels of NLRP3, ASC and caspase-1. Moreover, hemin reduced malondialdehyde and reactive oxygen species production, and inhibited NF-?B and NLRP3 inflammasome activity. Meanwhile, hemin significantly increased HO-1 mRNA and protein expression and HO-1 enzymatic activity. In contrast, no significant differences were observed between the CLP and ZnPP groups. Our study suggests that hemin-inhibited NLRP3 inflammasome activation involved HO-1, reducing IL-1? and IL-18 secretion and limiting the inflammatory response. PMID:24583148

Luo, Yun-peng; Jiang, Lei; Kang, Kai; Fei, Dong-sheng; Meng, Xiang-lin; Nan, Chuan-chuan; Pan, Shang-ha; Zhao, Ming-ran; Zhao, Ming-yan

2014-05-01

340

Metabolic acidosis stimulates muscle protein degradation by activating the adenosine triphosphate-dependent pathway involving ubiquitin and proteasomes.  

PubMed Central

Metabolic acidosis often leads to loss of body protein due mainly to accelerated protein breakdown in muscle. To identify which proteolytic pathway is activated, we measured protein degradation in incubated epitrochlearis muscles from acidotic (NH4Cl-treated) and pair-fed rats under conditions that block different proteolytic systems. Inhibiting lysosomal and calcium-activated proteases did not reduce the acidosis-induced increase in muscle proteolysis. However, when ATP production was also blocked, proteolysis fell to the same low level in muscles of acidotic and control rats. Acidosis, therefore, stimulates selectively an ATP-dependent, nonlysosomal, proteolytic process. We also examined whether the activated pathway involves ubiquitin and proteasomes (multicatalytic proteinases). Acidosis was associated with a 2.5- to 4-fold increase in ubiquitin mRNA in muscle. There was no increase in muscle heat shock protein 70 mRNA or in kidney ubiquitin mRNA, suggesting specificity of the response. Ubiquitin mRNA in muscle returned to control levels within 24 h after cessation of acidosis. mRNA for subunits of the proteasome (C2 and C3) in muscle were also increased 4-fold and 2.5-fold, respectively, with acidosis; mRNA for cathepsin B did not change. These results are consistent with, but do not prove that acidosis stimulates muscle proteolysis by activating the ATP-ubiquitin-proteasome-dependent, proteolytic pathway. Images

Mitch, W E; Medina, R; Grieber, S; May, R C; England, B K; Price, S R; Bailey, J L; Goldberg, A L

1994-01-01

341

Direct evidence for the involvement of capsular polysaccharide in the immunoprotective activity of Klebsiella pneumoniae ribosomal preparations.  

PubMed Central

Previous work has demonstrated the capsular serotypic specificity of the protection conferred on mice by Klebsiella pneumoniae ribosomal preparations. The data in these studies support the hypothesis that capsular polysaccharide plays at least some role in the specificity of the protection conferred by ribosomal preparations. In this investigation, the presence of capsular polysaccharide and lipopolysaccharide in K. pneumoniae ribosomal preparations was demonstrated by using immunodiffusion tests. Lipopolysaccharide content was determined for mice treated with actinomycin D. The serotype of O antigen did not play a role in the orientation of the specificity of the protection. The possibility that lipopolysaccharide might act as an adjuvant was not unlikely since the ribosomal preparations which contained the greatest amounts of lipopolysaccharide appeared to be the most immunoprotective preparations. Ribosomal preparations extracted from a noncapsulated mutant of K. pneumoniae did not protect mice. This finding suggested that capsular polysaccharide might play a role in the immunoprotective activity of ribosomes. This hypothesis was tested by using K. pneumoniae K2 bacteriophage-associated-glycanase, which specifically hydrolyzed K. pneumoniae K2 capsular polysaccharide and thereby suppressed the immunoprotective activity of K. pneumoniae K2 ribosomal preparations. In contrast, the K2 bacteriophage-associated glycanase did not interfere with the immunoprotective activity of K. pneumoniae K1 ribosomal preparations. These results clearly demonstrate that capsular polysaccharide, which is an extraribosomal antigen, is involved in the immunoprotective activity of K. pneumoniae ribosomal preparations. Images

Riottot, M M; Fournier, J M; Jouin, H

1981-01-01

342

Protein tyrosine phosphatase activities are involved in apoptotic cancer cell death induced by GL331, a new homolog of etoposide.  

PubMed

GL331 is a semisynthetic topoisomerase II inhibitor derived from a plant toxin podophyllotoxin. In 72-h exposure assays, LD50 values of GL331 range from 0.5 to 2 microM, which are three- to ten-fold lower than those of its homologous compound etoposide (VP-16), depending on different cancer cell lines including nasopharyngeal, hepatocellular, gastric, cervical and colon cancer types. Apoptotic DNA ladders could be detected when cancer cells were treated with GL331 for 24 h even if the Bcl-2 and Bax protein levels were not altered during the period. Besides acting as topoisomerase II inhibitors, both GL331 and VP-16 decrease the cellular protein tyrosine kinase (PTK) activities in cancer cells. The activities of protein tyrosine phosphatase (PTP) are significantly increased after GL331 treatment but are not affected by VP-16. GL331-induced internucleosomal cleavage can be efficiently prevented by two inhibitors of PTP, sodium orthovanadate and zinc chloride, but not by okadaic acid, which inhibits serine/threonine phosphatase activity. These results indicate that GL331 may induce apoptotic cell death, and that activation of protein tyrosine phosphatases may be involved in this process. PMID:9018084

Huang, T S; Shu, C H; Shih, Y L; Huang, H C; Su, Y C; Chao, Y; Yang, W K; Whang-Peng, J

1996-12-20

343

GABA/sub B/ receptor activation inhibits Ca/sup 2 +/-activated potassium channels in synaptosomes: involvement of G-proteins  

SciTech Connect

/sup 86/Rb-efflux assay from preloaded synaptosomes of rat cerebral cortex was developed to study the effect of GABA/sub B/ receptor agonist baclofen on Ca/sup 2 +/-activated K/sup +/-channels. Depolarization of /sup 86/Rb-loaded synaptosomes in physiological buffer increased Ca/sup 2 +/-activated /sup 86/Rb-efflux by 400%. The /sup 86/Rb-efflux was blocked by quinine sulfate, tetraethylammonium, and La/sup 3 +/ indicating the involvement of Ca/sup 2 +/-activated K/sup +/-channels. (-)Baclofen inhibited Ca/sup 2 +/-activated /sup 86/Rb-efflux in a stereospecific manner. The inhibitory effect of (-)baclofen was mediated by GABA/sub B/ receptor activation, since it was blocked by GABA/sub B/ antagonist phaclofen, but not by bicuculline. Further, pertussis toxin also blocked the ability of baclofen or depolarizing action to affect Ca/sup 2 +/-activated K/sup +/-channels. These results suggest that baclofen inhibits Ca/sup 2 +/-activated K/sup +/-channels in synaptosomes and these channels are regulated by G-proteins. This assay may provide an ideal in vitro model to study GABA/sub B/ receptor pharmacology.

Ticku, M.K.; Delgado, A.

1989-01-01

344

Endothelial cell permeability during hantavirus infection involves factor XII-dependent increased activation of the kallikrein-kinin system.  

PubMed

Hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) are diseases caused by hantavirus infections and are characterized by vascular leakage due to alterations of the endothelial barrier. Hantavirus-infected endothelial cells (EC) display no overt cytopathology; consequently, pathogenesis models have focused either on the influx of immune cells and release of cytokines or on increased degradation of the adherens junction protein, vascular endothelial (VE)-cadherin, due to hantavirus-mediated hypersensitization of EC to vascular endothelial growth factor (VEGF). To examine endothelial leakage in a relevant in vitro system, we co-cultured endothelial and vascular smooth muscle cells (vSMC) to generate capillary blood vessel-like structures. In contrast to results obtained in monolayers of cultured EC, we found that despite viral replication in both cell types as well as the presence of VEGF, infected in vitro vessels neither lost integrity nor displayed evidence of VE-cadherin degradation. Here, we present evidence for a novel mechanism of hantavirus-induced vascular leakage involving activation of the plasma kallikrein-kinin system (KKS). We show that incubation of factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen (HK) plasma proteins with hantavirus-infected EC results in increased cleavage of HK, higher enzymatic activities of FXIIa/kallikrein (KAL) and increased liberation of bradykinin (BK). Measuring cell permeability in real-time using electric cell-substrate impedance sensing (ECIS), we identified dramatic increases in endothelial cell permeability after KKS activation and liberation of BK. Furthermore, the alterations in permeability could be prevented using inhibitors that directly block BK binding, the activity of FXIIa, or the activity of KAL. Lastly, FXII binding and autoactivation is increased on the surface of hantavirus-infected EC. These data are the first to demonstrate KKS activation during hantavirus infection and could have profound implications for treatment of hantavirus infections. PMID:23874198

Taylor, Shannon L; Wahl-Jensen, Victoria; Copeland, Anna Maria; Jahrling, Peter B; Schmaljohn, Connie S

2013-01-01

345

Endothelial Cell Permeability during Hantavirus Infection Involves Factor XII-Dependent Increased Activation of the Kallikrein-Kinin System  

PubMed Central

Hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) are diseases caused by hantavirus infections and are characterized by vascular leakage due to alterations of the endothelial barrier. Hantavirus-infected endothelial cells (EC) display no overt cytopathology; consequently, pathogenesis models have focused either on the influx of immune cells and release of cytokines or on increased degradation of the adherens junction protein, vascular endothelial (VE)-cadherin, due to hantavirus-mediated hypersensitization of EC to vascular endothelial growth factor (VEGF). To examine endothelial leakage in a relevant in vitro system, we co-cultured endothelial and vascular smooth muscle cells (vSMC) to generate capillary blood vessel-like structures. In contrast to results obtained in monolayers of cultured EC, we found that despite viral replication in both cell types as well as the presence of VEGF, infected in vitro vessels neither lost integrity nor displayed evidence of VE-cadherin degradation. Here, we present evidence for a novel mechanism of hantavirus-induced vascular leakage involving activation of the plasma kallikrein-kinin system (KKS). We show that incubation of factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen (HK) plasma proteins with hantavirus-infected EC results in increased cleavage of HK, higher enzymatic activities of FXIIa/kallikrein (KAL) and increased liberation of bradykinin (BK). Measuring cell permeability in real-time using electric cell-substrate impedance sensing (ECIS), we identified dramatic increases in endothelial cell permeability after KKS activation and liberation of BK. Furthermore, the alterations in permeability could be prevented using inhibitors that directly block BK binding, the activity of FXIIa, or the activity of KAL. Lastly, FXII binding and autoactivation is increased on the surface of hantavirus-infected EC. These data are the first to demonstrate KKS activation during hantavirus infection and could have profound implications for treatment of hantavirus infections.

Taylor, Shannon L.; Wahl-Jensen, Victoria; Copeland, Anna Maria; Jahrling, Peter B.; Schmaljohn, Connie S.

2013-01-01

346

Factors involved in the rise of phosphoenolpyruvate carboxylase-kinase activity caused by salinity in sorghum leaves.  

PubMed

Salinity increases phosphoenolpyruvate carboxylase kinase (PEPCase-k) activity in sorghum leaves. This work has been focused on the mechanisms responsible for this phenomenon. The light-triggered expression of SbPPCK1 gene, accountable for the photosynthetic C4-PEPCase-k, is controlled by a complex signal transduction chain involving phospholipases C and D (PLC and PLD). These two phospholipase-derived signalling pathways were functional in salinized plants. Pharmacological agents that act on PLC (U-73122, neomycin) or PLD (n-butanol) derived signals, blocked the expression of SbPPCK1, but had little effect on PEPCase-k activity. This discrepancy was further noticed when SbPPCK1-3 gene expression and PEPCase-k activity were studied in parallel. At 172 mM, the main effect of NaCl was to decrease the rate of PEPCase-k protein turnover. Meanwhile, 258 mM NaCl significantly increased both SbPPCK1 and SbPPCK2 gene expression and/or mRNA stability. The combination of these factors contributed to maintain a high PEPCase-k activity in salinity. LiCl increased calcium-dependent protein kinase (CDPK) activity in illuminated sorghum leaves while it decreased the rate of PEPCase-k degradation. The latter effect was restrained by W7, an inhibitor of CDPK activity. Recombinant PEPCase-k protein was phosphorylated in vitro by PKA. A conserved phosphorylation motif, which can be recognized by PKA and by plant CDPKs, is present in the three PEPCase-ks proteins. Thus, it is possible that a phosphorylation event could be controlling (increasing) the stability of PEPCase-k in salinity. These results propose a new mechanism of regulation of PEPCase-k levels, and highlight the relevance of the preservation of key metabolic elements during the bulk degradation of proteins, which is commonly associated to stress. PMID:23408154

Monreal, José A; Arias-Baldrich, Cirenia; Pérez-Montaño, Francisco; Gandullo, Jacinto; Echevarría, Cristina; García-Mauriño, Sofía

2013-05-01

347

A cannabinoid receptor 1 mutation proximal to the DRY motif results in constitutive activity and reveals intramolecular interactions involved in receptor activation  

PubMed Central

Activation of a G-protein-coupled receptor involves changes in specific microdomain interactions within the transmembrane region of the receptor. Here, we have focused on the role of L207, proximal to the DRY motif of the human cannabinoid receptor 1 in the interconversion of the receptor resting and active states. Ligand binding analysis of the mutant receptor L207A revealed an enhanced affinity for agonists (three- to six-fold) and a diminished affinity for inverse agonists (19- to 35-fold) compared to the wild-type receptor, properties characteristic of constitutive activity. To further examine whether this mutant adopts a ligand-independent, active form, treatment with GTP?S was used to inhibit G protein coupling. Under these conditions, the L207A receptor exhibited a 10-fold increase in affinity for the inverse agonist SR141716A, consistent with a shift away from an enhanced precoupled state. Analysis of the cellular activity of the L207A receptor showed elevated basal cyclic AMP accumulation relative to the wild type that is inhibited by SR141716A, consistent with receptor-mediated Gs precoupling. Using toxins to selectively abrogate Gs or Gi coupling, we found that CP55940 nonetheless induced only a Gi response suggesting a strong preference of this ligand-bound form for Gi in this system. Molecular dynamics simulations reveal that the single residue change of L207A impacts the association of TM3 and TM6 in the receptor by altering hydrophobic interactions involving L207, the salt bridge involving the Arg of the DRY motif, and the helical structure of TM6, consistent with events leading to activation. The structural alterations parallel those observed in models of a mutant CB1 receptor T210I, with established constitutive activity (D’Antona, A.M., Ahn, K.H. and Kendall, D.A., 2006. Mutations of CB1 T210 produce active and inactive receptor forms: correlations with ligand affinity, receptor stability, and cellular localization. Biochemistry, 45, 5606–5617).

D'Antona, Aaron M.; Ahn, Kwang H.; Wang, Lei; Mierke, Dale F.; Lucas-Lenard, Jean; Kendall, Debra A.

2009-01-01

348

Ca2+/Calmodulin-Dependent Protein Kinase Kinase Is Not Involved in Hypothalamic AMP-Activated Protein Kinase Activation by Neuroglucopenia  

PubMed Central

Hypoglycemia and neuroglucopenia stimulate AMP-activated protein kinase (AMPK) activity in the hypothalamus and this plays an important role in the counterregulatory responses, i.e. increased food intake and secretion of glucagon, corticosterone and catecholamines. Several upstream kinases that activate AMPK have been identified including Ca2+/Calmodulin-dependent protein kinase kinase (CaMKK), which is highly expressed in neurons. However, the involvement of CaMKK in neuroglucopenia-induced activation of AMPK in the hypothalamus has not been tested. To determine whether neuroglucopenia-induced AMPK activation is mediated by CaMKK, we tested whether STO-609 (STO), a CaMKK inhibitor, would block the effects of 2-deoxy-D-glucose (2DG)-induced neuroglucopenia both ex vivo on brain sections and in vivo. Preincubation of rat brain sections with STO blocked KCl-induced ?1 and ?2-AMPK activation but did not affect AMPK activation by 2DG in the medio-basal hypothalamus. To confirm these findings in vivo, STO was pre-administrated intracerebroventricularly (ICV) in rats 30 min before 2DG ICV injection (40 µmol) to induce neuroglucopenia. 2DG-induced neuroglucopenia lead to a significant increase in glycemia and food intake compared to saline-injected control rats. ICV pre-administration of STO (5, 20 or 50 nmol) did not affect 2DG-induced hyperglycemia and food intake. Importantly, activation of hypothalamic ?1 and ?2-AMPK by 2DG was not affected by ICV pre-administration of STO. In conclusion, activation of hypothalamic AMPK by 2DG-induced neuroglucopenia is not mediated by CaMKK.

Tsuji, Youki; Peroni, Odile D.; Kahn, Barbara B.

2012-01-01

349

Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.  

PubMed

The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species. PMID:21462837

Lixandru, Brîndu?a-Elena; Dr?cea, Nicoleta Olgu?a; Dragomirescu, Cristiana Cerasella; Dr?gulescu, Elena Carmina; Coldea, Ileana Lumini?a; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codi??, Irina

2010-01-01

350

The anti-apoptotic effect of leukotriene D4 involves the prevention of caspase 8 activation and Bid cleavage.  

PubMed Central

We have shown in a previous study that leukotriene D(4) (LTD(4)) signalling increases cell survival and proliferation in intestinal epithelial cells [Ohd, Wikström and Sjölander (2000) Gastroenterology 119, 1007-1018]. This is highly interesting since inflammatory conditions of the bowel are associated with an increased risk of developing colon cancer. The enzyme cyclo-oxygenase 2 (COX-2) is important in this context since it is up-regulated in colon cancer tissues and in tumour cell lines. Treatment with the COX-2-specific inhibitor N -(2-cyclohexyloxy-4-nitrophenyl)methane sulphonamide has been shown previously to cause apoptosis in intestinal epithelial cells. In the present study, we attempted to elucidate the underlying mechanisms and we can now show that a mitochondrial pathway is employed. Inhibition of COX-2 causes release of cytochrome c, as shown by both Western-blot and microscopy studies, and as with apoptosis, this is significantly decreased by LTD(4). Since previous studies showed increased Bcl-2 levels on LTD(4) stimulation, we further studied apoptotic regulation at the mitochondrial level. From this we could exclude the involvement of the anti-apoptotic protein Bcl-X(L) as well as its pro-apoptotic counterpart Bax, since they are not expressed. Furthermore, the activity of the pro-apoptotic protein Bad (Bcl-2/Bcl-X(L)-antagonist, causing cell death) was completely unaffected. However, inhibition of COX-2 caused cleavage of caspase 8 into a 41 kDa fragment associated with activation and caused the appearance of an activated 15 kDa fragment of Bid. This indicates that N -(2-cyclohexyloxy-4-nitrophenyl)methane sulphonamide-induced apoptosis is mediated by the activation of caspase 8, via generation of truncated Bid, and thereafter release of cytochrome c. Interestingly, LTD(4) not only reverses the effects induced by inhibition of COX-2 but also reduces the apoptotic potential by lowering the basal level of caspase 8 activation and truncated Bid generation.

Wikstrom, Katarina; Juhas, Maria; Sjolander, Anita

2003-01-01

351

Involvement of serine protease and proteinase-activated receptor 2 in dermatophyte-associated itch in mice.  

PubMed

We investigated the involvement of serine protease and proteinase-activated receptor 2 (PAR(2)) in dermatophyte-induced itch in mice. An intradermal injection of an extract of the dermatophyte Arthroderma vanbreuseghemii (ADV) induced hind-paw scratching, an itch-related behavior. ADV extract-induced scratching was inhibited by the opioid receptor antagonists naloxone and naltrexone, the serine protease inhibitor nafamostat mesylate, and the PAR(2) receptor antagonist FSLLRY-NH(2). ADV extract-induced scratching was not inhibited by the H(1) histamine receptor antagonist terfenadine or by mast cell deficiency. Heat pretreatment of the ADV extract markedly reduced the scratch-inducing and serine protease activities. Proteolytic cleavage within the extracellular N terminus of the PAR(2) receptor exposes a sequence that serves as a tethered ligand for the receptor. The ADV extract as well as tryptase and trypsin cleaved a synthetic N-terminal peptide of the PAR(2) receptor. The present results suggest that serine protease secreted by dermatophytes causes itching through activation of the PAR(2) receptors, which may be a causal mechanism of dernatophytosis itch. PMID:22761302

Andoh, Tsugunobu; Takayama, Yusuke; Yamakoshi, Takako; Lee, Jung-Bum; Sano, Ayako; Shimizu, Tadamichi; Kuraishi, Yasushi

2012-10-01

352

Nitric oxide and interleukins are involved in cell proliferation of RAW264.7 macrophages activated by viili exopolysaccharides.  

PubMed

Viili has been traditionally regarded as healthy food; viili exopolysaccharides (VEPS) function as antioxidants, but the molecular and cellular mechanisms, especially its immune functions, remain largely unclear. To assess VEPS's immunological roles, VEPS were separated by Sevage's method and purified by anion exchange chromatography. Cell proliferation, phagocytosis, releases of nitric oxide (NO), interleukin (IL)-1?, and IL-6, the inducible nitric oxide synthase (iNOS) gene expression by reverse transcription polymerase chain reaction (RT-PCR) and iNOS protein by Western blotting, and morphology by scanning electron microscopy in lipopolysaccharides (LPS)/VEPS-stimulated and non-stimulated RAW264.7 macrophages were analyzed. VEPS increased cell proliferation at 50-200 ?g/mL. The uptake of neutral red for the indication of phagocytosis and releases of NO, IL-6, and IL-1? were enhanced after exposure to LPS and VEPS. Gene expressions of iNOS, IL-6, and IL-1? and protein expressions of iNOS were increased with VEPS. The RAW264.7 cell treated with VEPS became flattened, a strong indication of the activation of macrophages. We concluded that VEPS promoted the activation of macrophages in which NO, IL-6, and IL-1? were involved; the release of NO and other cytokines may eventually activate lymphocytes, increasing nonspecific (innate) and specific immunity in humans. PMID:23515856

Wu, Junhua; Li, Mengxian; Liu, Ling; An, Qi; Zhang, Jinlu; Zhang, Jingkai; Li, Meiling; Duan, Weigang; Liu, Dequan; Li, Zhenjing; Luo, Cheng

2013-08-01

353

Possible Involvement of TLRs and Hemichannels in Stress-Induced CNS Dysfunction via Mastocytes, and Glia Activation  

PubMed Central

In the central nervous system (CNS), mastocytes and glial cells (microglia, astrocytes and oligodendrocytes) function as sensors of neuroinflammatory conditions, responding to stress triggers or becoming sensitized to subsequent proinflammatory challenges. The corticotropin-releasing hormone and glucocorticoids are critical players in stress-induced mastocyte degranulation and potentiation of glial inflammatory responses, respectively. Mastocytes and glial cells express different toll-like receptor (TLR) family members, and their activation via proinflammatory molecules can increase the expression of connexin hemichannels and pannexin channels in glial cells. These membrane pores are oligohexamers of the corresponding protein subunits located in the cell surface. They allow ATP release and Ca2+ influx, which are two important elements of inflammation. Consequently, activated microglia and astrocytes release ATP and glutamate, affecting myelinization, neuronal development, and survival. Binding of ligands to TLRs induces a cascade of intracellular events leading to activation of several transcription factors that regulate the expression of many genes involved in inflammation. During pregnancy, the previous responses promoted by viral infections and other proinflammatory conditions are common and might predispose the offspring to develop psychiatric disorders and neurological diseases. Such disorders could eventually be potentiated by stress and might be part of the etiopathogenesis of CNS dysfunctions including autism spectrum disorders and schizophrenia.

Aguirre, Adam; Maturana, Carola J.; Harcha, Paloma A.; Saez, Juan C.

2013-01-01

354

Fumonisin B1, a toxin produced by Fusarium verticillioides, modulates maize ?-1,3-glucanase activities involved in defense response.  

PubMed

Fusarium verticillioides is an important pathogen in maize that causes various diseases affecting all stages of plant development worldwide. The fungal pathogen could be seed borne or survive in soil and penetrate the germinating seed. Most F. verticillioides strains produce fumonisins, which are of concern because of their toxicity to animals and possibly humans, and because they enhance virulence against seedlings of some maize genotypes. In this work, we studied the action of fumonisin B1 (FB1) on the activity of maize ?-1,3-glucanases involved in plant defense response. In maize embryos, FB1 induced an acidic isoform while suppressing the activity of two basic isoforms. This acidic isoform was induced also with 2,6-dichloroisonicotinic acid, an analog of salicylic acid. Repression of the basic isoforms suggested a direct interaction of the enzymes with the mycotoxin as in vitro experiments showed that pure FB1 inhibited the basic ?-1,3-glucanases with an IC(50) of 53 ?M. When germinating maize embryos were inoculated with F. verticillioides the same dual effect on ?-1,3-glucanase activities that we observed with the pure toxin was reproduced. Similar levels of FB1 were recovered at 24 h germination in maize tissue when they were treated with pure FB1 or inoculated with an FB1-producing strain. These results suggest that ?-1,3-glucanases are a relevant physiological target and their modulation by FB1 might contribute to F. verticillioides colonization. PMID:22120123

Sánchez-Rangel, Diana; Sánchez-Nieto, Sobeida; Plasencia, Javier

2012-05-01

355

A short-type peptidoglycan recognition protein from the silkworm: expression, characterization and involvement in the prophenoloxidase activation pathway.  

PubMed

Recognition of invading microbes as non-self is the first step of immune responses. In insects, peptidoglycan recognition proteins (PGRPs) detect peptidoglycans (PGs) of bacterial cell wall, leading to the activation of defense responses. Twelve PGRPs have been identified in the silkworm, Bombyx mori, through bioinformatics analysis. However, their biochemical functions are mostly uncharacterized. In this study, we found PGRP-S5 transcript levels were up-regulated in fat body and midgut after bacterial infection. Using recombinant protein isolated from Escherichia coli, we showed that PGRP-S5 binds to PGs from certain bacterial strains and induces bacteria agglutination. Enzyme activity assay confirmed PGRP-S5 is an amidase; we also showed it is an antibacterial protein effective against both Gram-positive and -negative bacteria. Additionally, we demonstrated that specific recognition of PGs by PGRP-S5 is involved in the prophenoloxidase activation pathway. Together, these data suggest the silkworm PGRP-S5 functions as a pattern recognition receptor for the prophenoloxidase pathway initiation and as an effecter to inhibit bacterial growth as well. We finally discussed possible roles of PGRP-S5 as a receptor for antimicrobial peptide gene induction and as an immune modulator in the midgut. PMID:24508981

Chen, Kangkang; Liu, Chen; He, Yan; Jiang, Haobo; Lu, Zhiqiang

2014-07-01

356

Development of the parents' perception of their involvement in their child's tennis activity questionnaire (Q-PPICTA).  

PubMed

The purpose of this study was to develop and validate a questionnaire for assessing parents' perception of their involvement in their children's tennis activity (Q-PPICTA). The validation required four successive studies. In study 1, a preliminary version of the questionnaire was formulated after selecting and adapting items taken from existing questionnaires and interviews conducted with the parents of 36 young tennis players. Three factors for measuring parental involvement in sport were identified and retained: emotional, logistic, and informational supports. In study 2, exploratory factor analyses were performed on data collected from 214 parents of tennis players. Results attested the questionnaire's three-factor structure and ascertained its internal consistency. In study 3, a confirmatory factor analysis as well as tests on convergent and discriminant validity were carried out on data gathered from a different sample of 220 parents of tennis players. Statistics confirmed the questionnaire's three-factor structure and reliability. In study 4, the questionnaire's external construct validity was compared with another sample consisting of 192 parents and their children. Overall, results underlined satisfactory psychometric properties for the Q-PPICTA. Nevertheless, further studies are required to confirm the questionnaire's accuracy, reliability, and temporal validity. PMID:23438202

Hurtel, V; Lacassagne, M-F

2013-08-01

357

Thrombin activates AMP-activated protein kinase in endothelial cells via a pathway involving Ca2+/calmodulin-dependent protein kinase kinase beta.  

PubMed

AMP-activated protein kinase (AMPK) is a sensor of cellular energy state in response to metabolic stress and other regulatory signals. AMPK is controlled by upstream kinases which have recently been identified as LKB1 or Ca2+/calmodulin-dependent protein kinase kinase beta (CaMKKbeta). Our study of human endothelial cells shows that AMPK is activated by thrombin through a Ca2+-dependent mechanism involving the thrombin receptor protease-activated receptor 1 and Gq-protein-mediated phospholipase C activation. Inhibition of CaMKK with STO-609 or downregulation of CaMKKbeta using RNA interference decreased thrombin-induced AMPK activation significantly, indicating that CaMKKbeta was the responsible AMPK kinase. In contrast, downregulation of LKB1 did not affect thrombin-induced AMPK activation but abolished phosphorylation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleoside. Thrombin stimulation led to phosphorylation of acetyl coenzyme A carboxylase (ACC) and endothelial nitric oxide synthase (eNOS), two downstream targets of AMPK. Inhibition or downregulation of CaMKKbeta or AMPK abolished phosphorylation of ACC in response to thrombin but had no effect on eNOS phosphorylation, indicating that thrombin-stimulated phosphorylation of eNOS is not mediated by AMPK. Our results underline the role of Ca2+ as a regulator of AMPK activation in response to a physiologic stimulation. We also demonstrate that endothelial cells possess two pathways to activate AMPK, one Ca2+/CaMKKbeta dependent and one AMP/LKB1 dependent. PMID:16880506

Stahmann, Nadine; Woods, Angela; Carling, David; Heller, Regine

2006-08-01

358

Telomerase activity-independent function of telomerase reverse transcriptase is involved in acrylamide-induced neuron damage.  

PubMed

Abstract Polyacrylamide is used widely in industry, and its decomposition product, acrylamide (ACR), readily finds its way into commonly consumed cosmetics and baked and fried foods. ACR exerts potent neurotoxic effects in human and animal models. Telomerase reverse transcriptase (TERT), the catalytic subunit of telomerase, traditionally has been considered to play an important role in maintaining telomere length. Emerging evidence has shown, however, that TERT plays an important role in neuroprotection by inhibiting apoptosis and excitotoxicity, and by promoting angiogenesis, neuronal survival and neurogenesis, which are closely related to the telomere-independent functions of TERT. We investigated whether and how the TERT pathway is involved in ACR induced neurotoxicity in rat cortical neurons. We found that ACR 1) significantly reduced the viability of cortical neurons as measured by MTT assay, 2) induced neuron apoptosis as revealed by FITC-conjugated Annexin V/PI double staining and flow cytometry (FACS) analysis, 3) elevated expression of cleaved caspase-3, and 4) decreased bcl-2 expression of cortical neurons. ACR also increased intracellular ROS levels in cortical neurons, increased MDA levels and reduced GSH, SOD and GSH-Px levels in mitochondria in a dose-dependent manner. We found that TERT expression in mitochondria was increased by ACR at concentrations of 2.5 and 5.0 mM, but TERT expression was decreased by 10 mM ACR. Telomerase activity, however, was undetectable in rat cortical neurons. Our results suggest that the TERT pathway is involved in ACR induced apoptosis of cortical neurons. TERT also may exert its neuroprotective role in a telomerase activity-independent way, especially in mitochondria. PMID:24279610

Zhang, P; Pan, H; Wang, J; Liu, X; Hu, X

2014-07-01

359

Effect of game format on heart rate, activity profile, and player involvement in elite and recreational youth players.  

PubMed

The purpose of this study was to evaluate activity profile, aerobic load, and player involvement in two game formats of recreational and elite youth football for two age groups. A total of 152 youth players participated, with 45 U10 players playing 5v5 and 8v8 games, and 41 U13 players playing 8v8 and 11v11 (20?min) games. Activity profile, heart rate (HR), and technical actions were measured during all games using 10?Hz GPS, video filming, and HR monitors. For U10, no difference was found in total distance covered (1754?±?237 vs 1771?±?314?m, P?=?0.650, d?=?0.06), whereas mean HR (174?±?10 vs 168?±?12?bpm, P?=?0.001, d?=?0.59) and number of technical actions (65.1?±?24.0 vs 36.9?±?20.4, P?involvement of youth players both at elite level and recreational level. PMID:24944130

Randers, M B; Andersen, T B; Rasmussen, L S; Larsen, M N; Krustrup, P

2014-08-01

360

The yeast mitogen-activated protein kinase Slt2 is involved in the cellular response to genotoxic stress  

PubMed Central

Background The maintenance of genomic integrity is essential for cell viability. Complex signalling pathways (DNA integrity checkpoints) mediate the response to genotoxic stresses. Identifying new functions involved in the cellular response to DNA-damage is crucial. The Saccharomyces cerevisiae SLT2 gene encodes a member of the mitogen-activated protein kinase (MAPK) cascade whose main function is the maintenance of the cell wall integrity. However, different observations suggest that SLT2 may also have a role related to DNA metabolism. Results This work consisted in a comprehensive study to connect the Slt2 protein to genome integrity maintenance in response to genotoxic stresses. The slt2 mutant strain was hypersensitive to a variety of genotoxic treatments, including incubation with hydroxyurea (HU), methylmetanosulfonate (MMS), phleomycin or UV irradiation. Furthermore, Slt2 was activated by all these treatments, which suggests that Slt2 plays a central role in the cellular response to genotoxic stresses. Activation of Slt2 was not dependent on the DNA integrity checkpoint. For MMS and UV, Slt2 activation required progression through the cell cycle. In contrast, HU also activated Slt2 in nocodazol-arrested cells, which suggests that Slt2 may respond to dNTP pools alterations. However, neither the protein level of the distinct ribonucleotide reductase subunits nor the dNTP pools were affected in a slt2 mutant strain. An analysis of the checkpoint function revealed that Slt2 was not required for either cell cycle arrest or the activation of the Rad53 checkpoint kinase in response to DNA damage. However, slt2 mutant cells showed an elongated bud and partially impaired Swe1 degradation after replicative stress, indicating that Slt2 could contribute, in parallel with Rad53, to bud morphogenesis control after genotoxic stresses. Conclusions Slt2 is activated by several genotoxic treatments and is required to properly cope with DNA damage. Slt2 function is important for bud morphogenesis and optimal Swe1 degradation under replicative stress. The MAPK Slt2 appears as a new player in the cellular response to genotoxic stresses.

2012-01-01

361

Activation of a PTX-insensitive G protein is involved in histamine-induced recombinant M-channel modulation  

PubMed Central

The M-type potassium current (IM) plays a dominant role in regulating membrane excitability and is modulated by many neurotransmitters. However, except in the case of bradykinin, the signal transduction pathways involved in M-channel modulation have not been fully elucidated. The channels underlying IM are produced by the coassembly of KCNQ2 and KCNQ3 channel subunits and can be expressed in heterologous systems where they can be modulated by several neurotransmitter receptors including histamine H1 receptors. In HEK293T cells, histamine acting via transiently expressed H1R produced a strong inhibition of recombinant M-channels but had no overt effects on the voltage dependence or voltage range of IM activation. In addition, the modulation of IM by histamine was not voltage sensitive, whereas channel gating, particularly deactivation, was accelerated by histamine. Non-hydrolysable guanine nucleotide analogues (GDP-?-S and GTP-?-S) and pertussis toxin (PTX) treatment demonstrated the involvement of a PTX-insensitive G protein in the signal transduction pathway mediating histamine-induced IM modulation. Abrogation of the histamine-induced modulation of IM by expression of a C-terminal construct of phospholipase C (PLC-?1-ct), which buffers activated G?q/11 subunits, implicates this G protein ? subunit in the modulatory pathway. On the other hand, abrogation of the histamine-induced modulation of IM by expression of two constructs which buffer free ?? subunits, transducin (G?t) and a C-terminal construct of a G protein receptor kinase (MAS-GRK2-ct), implicates ?? dimers in the modulatory pathway. These findings demonstrate that histamine modulates recombinant M-channels in HEK293T cells via a PTX-insensitive G protein, probably G?q/11, in a similar manner to a number of other G protein-coupled receptors. However, histamine-induced IM modulation in HEK293T cells is novel in that ?? subunits in addition to G?q/11 subunits appear to be involved in the modulation of KCNQ2/3 channel currents.

Guo, Juan; Schofield, Geoffery G

2002-01-01

362

T cell receptor for antigen induces linker for activation of T cell-dependent activation of a negative signaling complex involving Dok-2, SHIP-1, and Grb-2  

PubMed Central

Adaptor proteins positively or negatively regulate the T cell receptor for antigen (TCR) signaling cascade. We report that after TCR stimulation, the inhibitory adaptor downstream of kinase (Dok)-2 and its homologue Dok-1 are involved in a multimolecular complex including the lipid phosphatase Src homology 2 domain–containing inositol polyphosphate 5?-phosphatase (SHIP)-1 and Grb-2 which interacts with the membrane signaling scaffold linker for activation of T cells (LAT). Knockdown of LAT and SHIP-1 expression indicated that SHIP-1 favored recruitment of Dok-2 to LAT. Knockdown of Dok-2 and Dok-1 revealed their negative control on Akt and, unexpectedly, on Zap-70 activation. Our findings support the view that Dok-1 and -2 are critical elements of a LAT-dependent negative feedback loop that attenuates early TCR signal. Dok-1 and -2 may therefore exert a critical role in shaping the immune response and as gatekeepers for T cell tolerance.

Dong, Shen; Corre, Beatrice; Foulon, Eliane; Dufour, Evelyne; Veillette, Andre; Acuto, Oreste; Michel, Frederique

2006-01-01

363

Sequential Activation of Classic PKC and Estrogen Receptor ? Is Involved in Estradiol 17ss-D-Glucuronide-Induced Cholestasis  

PubMed Central

Estradiol 17ß-d-glucuronide (E17G) induces acute cholestasis in rat with endocytic internalization of the canalicular transporters bile salt export pump (Abcb11) and multidrug resistance-associated protein 2 (Abcc2). Classical protein kinase C (cPKC) and PI3K pathways play complementary roles in E17G cholestasis. Since non-conjugated estradiol is capable of activating these pathways via estrogen receptor alpha (ER?), we assessed the participation of this receptor in the cholestatic manifestations of estradiol glucuronidated-metabolite E17G in perfused rat liver (PRL) and in isolated rat hepatocyte couplets (IRHC). In both models, E17G activated ER?. In PRL, E17G maximally decreased bile flow, and the excretions of dinitrophenyl-glutathione, and taurocholate (Abcc2 and Abcb11 substrates, respectively) by 60% approximately; preadministration of ICI 182,780 (ICI, ER? inhibitor) almost totally prevented these decreases. In IRHC, E17G decreased the canalicular vacuolar accumulation of cholyl-glycylamido-fluorescein (Abcb11 substrate) with an IC50 of 91±1 µM. ICI increased the IC50 to 184±1 µM, and similarly prevented the decrease in the canalicular vacuolar accumulation of the Abcc2 substrate, glutathione-methylfluorescein. ICI also completely prevented E17G-induced delocalization of Abcb11 and Abcc2 from the canalicular membrane, both in PRL and IRHC. The role of ER? in canalicular transporter internalization induced by E17G was confirmed in ER?-knocked-down hepatocytes cultured in collagen sandwich. In IRHC, the protection of ICI was additive to that produced by PI3K inhibitor wortmannin but not with that produced by cPKC inhibitor Gö6976, suggesting that ER? shared the signaling pathway of cPKC but not that of PI3K. Further analysis of ER? and cPKC activations induced by E17G, demonstrated that ICI did not affect cPKC activation whereas Gö6976 prevented that of ER?, indicating that cPKC activation precedes that of ER?. Conclusion: ER? is involved in the biliary secretory failure induced by E17G and its activation follows that of cPKC.

Barosso, Ismael R.; Zucchetti, Andres E.; Boaglio, Andrea C.; Larocca, M. Cecilia; Taborda, Diego R.; Luquita, Marcelo G.; Roma, Marcelo G.; Crocenzi, Fernando A.; Sanchez Pozzi, Enrique J.

2012-01-01

364

De novo assembly and analysis of Cassia obtusifolia seed transcriptome to identify genes involved in the biosynthesis of active metabolites.  

PubMed

A cDNA library generated from seeds of Cassia obtusifolia was sequenced using Illumina/Solexa platform. More than 12,968,231 high quality reads were generated, and have been deposited in NCBI SRA (SRR 1012912). A total of 40,102 unigenes (>200?bp) were obtained with an average sequence length of 681?bp by de novo assembly. About 34,089 (85%) unique sequences were annotated and 8694 of the unique sequences were assigned to specific metabolic pathways by the Kyoto Encyclopedia of Genes and Genomes. Among them, 131 unigenes, which are involved in the biosynthesis and (or) regulation of anthraquinone, carotenoid, flavonoid, and lipid, the 4 best known active metabolites, were identified from cDNA library. In addition, three lipid transfer proteins were obtained, which may contribute to the lipid molecules transporting between biological membranes. Meanwhile, 30 cytochrome P450, 12 SAM-dependent methyltransferases, and 12 UDP-glucosyltransferase unigenes were identified, which could also be responsible for the biosynthesis of active metabolites. PMID:25035981

Liu, Zubi; Song, Tao; Zhu, Qiankun; Wang, Wanjun; Zhou, Jiayu; Liao, Hai

2014-05-01

365

AMPA-receptor activation is involved in the antiamnesic effect of DM 232 (unifiram) and DM 235 (sunifiram).  

PubMed

DM 232 and DM 235 are novel antiamnesic compounds structurally related to ampakines. The involvement of AMPA receptors in the mechanism of action of DM 232 and DM 235 was, therefore, investigated in vivo and in vitro. Both compounds (0.1 mg/kg(-1) i.p.) were able to reverse the amnesia induced by the AMPA receptor antagonist NBQX (30 mg/kg(-1) i.p.) in the mouse passive avoidance test. At the effective doses, the investigated compounds did not impair motor coordination, as revealed by the rota rod test, nor modify spontaneous motility and inspection activity, as revealed by the hole board test. DM 232 and DM 235 reversed the antagonism induced by kynurenic acid of the NMDA-mediated release of [(3)H]NA in the kynurenate test performed in rat hippocampal slices. This effect was abolished by NBQX. DM 232 increases, in a concentration dependent manner, excitatory synaptic transmission in the rat hippocampus in vitro. These results suggest that DM 232 and DM 235 act as cognition enhancers through the activation of the AMPA-mediated neurotransmission system. PMID:14600801

Galeotti, N; Ghelardini, C; Pittaluga, A; Pugliese, A M; Bartolini, A; Manetti, D; Romanelli, M N; Gualtieri, F

2003-12-01

366

Angiotensin II AT1 Receptors Are Involved in Neuronal Activation Induced by Amphetamine in a Two-Injection Protocol  

PubMed Central

It was already found that Ang II AT1 receptors are involved in the neuroadaptative changes induced by a single exposure to amphetamine, and such changes are related to the development of behavioral and neurochemical sensitization. The induction of the immediately early gene c-fos has been used to define brain activated areas by amphetamine. Our aim was to evaluate the participation of AT1 receptors in the neuronal activation induced by amphetamine sensitization. The study examined the c-fos expression in mesocorticolimbic areas induced by amphetamine challenge (0.5?mg/kg i.p) in animals pretreated with candesartan, a selective AT1 receptor blocker (3?mg/kg p.o × 5 days), and amphetamine (5?mg/kg i.p) 3 weeks before the challenge. Increased c-fos immunoreactivity was found in response to the amphetamine challenge in the dorsomedial caudate-putamen and nucleus accumbens, and both responses were blunted by the AT1 receptor blocker pretreatment. In the infralimbic prefrontal cortex, increased c-fos immunoreactivity was found in response to amphetamine and saline challenge, and both were prevented by the AT1 receptor blocker. No differences were found neither in ventral tegmental area nor prelimbic cortex between groups. Our results indicate an important role for brain Ang II in the behavioral and neuronal sensitization induced by amphetamine.

Paz, Maria Constanza; Marchese, Natalia Andrea; Cancela, Liliana M.

2013-01-01

367

Increased origin activity in transformed versus normal cells: identification of novel protein players involved in DNA replication and cellular transformation.  

PubMed

Using libraries of replication origins generated previously, we identified three clones that supported the autonomous replication of their respective plasmids in transformed, but not in normal cells. Assessment of their in vivo replication activity by in situ chromosomal DNA replication assays revealed that the chromosomal loci corresponding to these clones coincided with chromosomal replication origins in all cell lines, which were more active by 2-3-fold in the transformed by comparison to the normal cells. Evaluation of pre-replication complex (pre-RC) protein abundance at these origins in transformed and normal cells by chromatin immunoprecipitation assays, using anti-ORC2, -cdc6 and -cdt1 antibodies, showed that they were bound by these pre-RC proteins in all cell lines, but a 2-3-fold higher abundance was observed in the transformed by comparison to the normal cells. Electrophoretic mobility shift assays (EMSAs) performed on the most efficiently replicating clone, using nuclear extracts from the transformed and normal cells, revealed the presence of a DNA replication complex in transformed cells, which was barely detectable in normal cells. Subsequent supershift EMSAs suggested the presence of transformation-specific complexes. Mass spectrometric analysis of these complexes revealed potential new protein players involved in DNA replication that appear to correlate with cellular transformation. PMID:20064876

Di Paola, Domenic; Rampakakis, Emmanouil; Chan, Man Kid; Arvanitis, Dina N; Zannis-Hadjopoulos, Maria

2010-04-01

368

Microarray Analysis of Genes Involved with Shell Strength in Layer Shell Gland at the Early Stage of Active Calcification  

PubMed Central

The objective of this study was to get a comprehensive understanding of how genes in chicken shell gland modulate eggshell strength at the early stage of active calcification. Four 32-week old of purebred Xianju hens with consistent high or low shell breakage strength were grouped into two pairs. Using Affymetrix Chicken Array, a whole-transcriptome analysis was performed on hen’s shell gland at 9 h post oviposition. Gene ontology enrichment analysis for differentially expressed (DE) transcripts was performed using the web-based GOEAST, and the validation of DE-transcripts was tested by qRT-PCR. 1,195 DE-transcripts, corresponding to 941 unique genes were identified in hens with strong eggshell compared to weak shell hens. According to gene ontology annotations, there are 77 DE-transcripts encoding ion transporters and secreted extracellular matrix proteins, and at least 26 DE-transcripts related to carbohydrate metabolism or post-translation glycosylation modification; furthermore, there are 88 signaling DE-transcripts. GO term enrichment analysis suggests that some DE-transcripts mediate reproductive hormones or neurotransmitters to affect eggshell quality through a complex suite of biophysical processes. These results reveal some candidate genes involved with eggshell strength at the early stage of active calcification which may facilitate our understanding of regulating mechanisms of eggshell quality.

Liu, Zhangguo; Zheng, Qi; Zhang, Xueyu; Lu, Lizhi

2013-01-01

369

The D14 and R138 ion pair is involved in dimeric arginine kinase activity, structural stability and folding.  

PubMed

Arginine kinase (AK) is a key enzyme in cellular energy metabolism of invertebrates. There are two conserved amino acid residues D14 and R138 in dimeric AK which form inter-subunit hydrogen bond. In Stichopus japonicus AK, mutations in these residues caused pronounced loss of activity, conformational changes and distinct substrate synergism alteration. Mutations (R138G, R138A and D14G) abolished D14 and R138 interaction disrupted the structure or conformation of S. japonicus AK. These R138G, R138A and D14G mutations changed their native assembles of dimeric AK and caused them in a partially unfolded state. The partially unfolded state of these mutant AKs made them prone to aggregate under environmental stress. The D14E/R138K and R138K mutant AKs showed similar characteristics to those of WT AK for forming the interaction which could replacement roles of D14 and R138 interaction. These results suggested that D14 and R138 interaction is involved in AK's activity, substrate synergism and structural stability. PMID:24582938

Geng, Hong-Li; Bian, Mei-Ru; Liu, Yang; Cao, Jiang; Chen, Chong; Wang, Zhi-Yuan; Li, Zhen-Yu; Zeng, Ling-Yu; Wang, Xiao-Yun; Wu, Qing-Yun; Xu, Kai-Lin

2014-05-01

370

HIF-1 Regulates Iron Homeostasis in Caenorhabditis elegans by Activation and Inhibition of Genes Involved in Iron Uptake and Storage  

PubMed Central

Caenorhabditis elegans ftn-1 and ftn-2, which encode the iron-storage protein ferritin, are transcriptionally inhibited during iron deficiency in intestine. Intestinal specific transcription is dependent on binding of ELT-2 to GATA binding sites in an iron-dependent enhancer (IDE) located in ftn-1 and ftn-2 promoters, but the mechanism for iron regulation is unknown. Here, we identify HIF-1 (hypoxia-inducible factor -1) as a negative regulator of ferritin transcription. HIF-1 binds to hypoxia-response elements (HREs) in the IDE in vitro and in vivo. Depletion of hif-1 by RNA interference blocks transcriptional inhibition of ftn-1 and ftn-2 reporters, and ftn-1 and ftn-2 mRNAs are not regulated in a hif-1 null strain during iron deficiency. An IDE is also present in smf-3 encoding a protein homologous to mammalian divalent metal transporter-1. Unlike the ftn-1 IDE, the smf-3 IDE is required for HIF-1–dependent transcriptional activation of smf-3 during iron deficiency. We show that hif-1 null worms grown under iron limiting conditions are developmentally delayed and that depletion of FTN-1 and FTN-2 rescues this phenotype. These data show that HIF-1 regulates intestinal iron homeostasis during iron deficiency by activating and inhibiting genes involved in iron uptake and storage.

Romney, Steven Joshua; Newman, Ben S.; Thacker, Colin; Leibold, Elizabeth A.

2011-01-01

371

The practice of effective involvment of Master and Graduate students to research activity for space science and technology.  

NASA Astrophysics Data System (ADS)

One of serious problems both for fundamental space research and various applied fields of space exploration is an effective involvement of graduates to real scientific or engineering work. The basic education even of high quality does not prepare a graduate well enough to start productive work in such specific fields as space science and engineering. An idea to organize the thematic educational training with elements of participation in real projects based on a profile research of Academic and industry organizations already at Master's degree program level was successfully implemented in Russian Academy in cooperation with Moscow Institute of Physics and Technology. However at present, under severe competition with commercial companies, we need to search for new additional ways to intensify young talented people inflow to the field of space science and applications. Various activities aimed to resolve this problem are now conducted by Russian Space Science Council and Russian Academy of Sciences, such as educational discourses for high-schools and students of junior level. We discuss the first results of this practice. Very important part of this activity is development of effective integration into international educational and outreach programs. The report is prepared in a frame of "Young Scientists Support Program" of Russian Academy of Sciences.

Zelenyi, Lev; Alferov, A.; Zeleniy, Lev; Veselov, M.; Rodin, V.

372

HIF-1 regulates iron homeostasis in Caenorhabditis elegans by activation and inhibition of genes involved in iron uptake and storage.  

PubMed

Caenorhabditis elegans ftn-1 and ftn-2, which encode the iron-storage protein ferritin, are transcriptionally inhibited during iron deficiency in intestine. Intestinal specific transcription is dependent on binding of ELT-2 to GATA binding sites in an iron-dependent enhancer (IDE) located in ftn-1 and ftn-2 promoters, but the mechanism for iron regulation is unknown. Here, we identify HIF-1 (hypoxia-inducible factor -1) as a negative regulator of ferritin transcription. HIF-1 binds to hypoxia-response elements (HREs) in the IDE in vitro and in vivo. Depletion of hif-1 by RNA interference blocks transcriptional inhibition of ftn-1 and ftn-2 reporters, and ftn-1 and ftn-2 mRNAs are not regulated in a hif-1 null strain during iron deficiency. An IDE is also present in smf-3 encoding a protein homologous to mammalian divalent metal transporter-1. Unlike the ftn-1 IDE, the smf-3 IDE is required for HIF-1-dependent transcriptional activation of smf-3 during iron deficiency. We show that hif-1 null worms grown under iron limiting conditions are developmentally delayed and that depletion of FTN-1 and FTN-2 rescues this phenotype. These data show that HIF-1 regulates intestinal iron homeostasis during iron deficiency by activating and inhibiting genes involved in iron uptake and storage. PMID:22194696

Romney, Steven Joshua; Newman, Ben S; Thacker, Colin; Leibold, Elizabeth A

2011-12-01

373

Part of Ran Is Associated with AKAP450 at the Centrosome: Involvement in Microtubule-organizing Activity  

PubMed Central

The small Ran GTPase, a key regulator of nucleocytoplasmic transport, is also involved in microtubule assembly and nuclear membrane formation. Herein, we show by immunofluorescence, immunoelectron microscopy, and biochemical analysis that a fraction of Ran is tightly associated with the centrosome throughout the cell cycle. Ran interaction with the centrosome is mediated by the centrosomal matrix A kinase anchoring protein (AKAP450). Accordingly, when AKAP450 is delocalized from the centrosome, Ran is also delocalized, and as a consequence, microtubule regrowth or anchoring is altered, despite the persisting association of ?-tubulin with the centrosome. Moreover, Ran is recruited to Xenopus sperm centrosome during its activation for microtubule nucleation. We also demonstrate that centrosomal proteins such as centrin and pericentrin, but not ?-tubulin, AKAP450, or ninein, undertake a nucleocytoplasmic exchange as they concentrate in the nucleus upon export inhibition by leptomycin B. Together, these results suggest a challenging possibility, namely, that centrosome activity could depend upon nucleocytoplasmic exchange of centrosomal proteins and local Ran-dependent concentration at the centrosome.

Keryer, Guy; Di Fiore, Barbara; Celati, Claude; Lechtreck, Karl Ferdinand; Mogensen, Mette; Delouvee, Annie; Lavia, Patrizia; Bornens, Michel; Tassin, Anne-Marie

2003-01-01

374

Expression of genes involved in lipid metabolism correlate with peroxisome proliferator-activated receptor gamma expression in human skeletal muscle.  

PubMed

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) activation in adipose tissue is known to regulate genes involved in adipocyte differentiation and lipid metabolism. However, the role of PPAR-gamma in muscle remains unclear. To examine the potential regulation of genes by PPAR-gamma in human skeletal muscle, we used semiquantitative RT-PCR to determine the expression of PPAR-gamma, lipoprotein lipase (LPL), muscle carnitine palmitoyl transferase-1 (mCPT1), fatty acid-binding protein (FABP), carnitine acylcarnitine transferase (CACT), and glucose transporter-4 (GLUT4) in freeze-dried muscle samples from 14 male subjects. These samples were dissected free of adipose and other tissue contamination, as confirmed by minimal or absent adipsin expression. Between individuals, the messenger ribonucleic acid concentration of PPAR-gamma varied up to 3-fold, whereas LPL varied up to 6.5-fold, mCPT1 13-fold, FABP 4-fold, CACT 4-fold, and GLUT4 up to 3-fold. The expression of LPL (r2 = 0.54; P = 0.003), mCPT1 (r2 = 0.42; P = 0.012), and FABP (r2 = 0.324; P = 0.034) all correlated significantly with PPAR-gamma expression in the same samples. No significant correlation was observed between the expression of CACT and PPAR-gamma or between GLUT4 and PPAR-gamma. These findings demonstrate a relationship between PPAR-gamma expression and the expression of other genes of lipid metabolism in muscle and support the hypothesis that PPAR-gamma activators such as the antidiabetic thiazolidinediones may regulate fatty acid metabolism in skeletal muscle as well as in adipose tissue. PMID:11095470

Lapsys, N M; Kriketos, A D; Lim-Fraser, M; Poynten, A M; Lowy, A; Furler, S M; Chisholm, D J; Cooney, G J

2000-11-01

375

Trypanosome U-deletional RNA editing involves guide RNA-directed endonuclease cleavage, terminal U exonuclease, and RNA ligase activities.  

PubMed Central

We have studied the mechanism of accurate in vitro RNA editing of Trypanosoma brucei ATPase 6 mRNA, using four mRNA-guide RNA (gRNA) pairs that specify deletion of 2, 3, or 4 U residues at editing site 1 and mitochondrial extract. This extract not only catalyzes deletion of the specified number of U residues but also exhibits a novel endonuclease activity that cleaves the input pre-mRNA in a gRNA-directed manner, precisely at the phosphodiester bond predicted in a simple enzymatic model of RNA editing. This cleavage site is inconsistent with a chimera-based editing mechanism. The U residues to be deleted, present at the 3' end of the upstream cleavage product, are then removed evidently by a 3' U-specific exonuclease and not by a reverse reaction of terminal U transferase. RNA ligase can then join the mRNA halves through their newly formed 5' P and 3' OH termini, generating mRNA faithfully edited at the first editing site. This resultant, partially edited mRNA can then undergo accurate, gRNA-directed cleavage at editing site 2, again precisely as predicted by the enzymatic editing model. All of these enzymatic activities cofractionate with the U-deletion activity and may reside in a single complex. The data imply that each round of editing is a four-step process, involving (i) gRNA-directed cleavage of the pre-mRNA at the bond immediately 5' of the region base paired to the gRNA, (ii) U deletion from or U addition to the 3' OH of the upstream mRNA half, (iii) ligation of the mRNA halves, and (iv) formation of additional base pairing between the correctly edited site and the gRNA that directs subsequent nuclease cleavage at the next editing site. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6

Cruz-Reyes, J; Sollner-Webb, B

1996-01-01

376

The anti-apoptotic effect of leukotriene D4 involves the prevention of caspase 8 activation and Bid cleavage.  

PubMed

We have shown in a previous study that leukotriene D(4) (LTD(4)) signalling increases cell survival and proliferation in intestinal epithelial cells [Ohd, Wikström and Sjölander (2000) Gastroenterology 119, 1007-1018]. This is highly interesting since inflammatory conditions of the bowel are associated with an increased risk of developing colon cancer. The enzyme cyclo-oxygenase 2 (COX-2) is important in this context since it is up-regulated in colon cancer tissues and in tumour cell lines. Treatment with the COX-2-specific inhibitor N -(2-cyclohexyloxy-4-nitrophenyl)methane sulphonamide has been shown previously to cause apoptosis in intestinal epithelial cells. In the present study, we attempted to elucidate the underlying mechanisms and we can now show that a mitochondrial pathway is employed. Inhibition of COX-2 causes release of cytochrome c, as shown by both Western-blot and microscopy studies, and as with apoptosis, this is significantly decreased by LTD(4). Since previous studies showed increased Bcl-2 levels on LTD(4) stimulation, we further studied apoptotic regulation at the mitochondrial level. From this we could exclude the involvement of the anti-apoptotic protein Bcl-X(L) as well as its pro-apoptotic counterpart Bax, since they are not expressed. Furthermore, the activity of the pro-apoptotic protein Bad (Bcl-2/Bcl-X(L)-antagonist, causing cell death) was completely unaffected. However, inhibition of COX-2 caused cleavage of caspase 8 into a 41 kDa fragment associated with activation and caused the appearance of an activated 15 kDa fragment of Bid. This indicates that N -(2-cyclohexyloxy-4-nitrophenyl)methane sulphonamide-induced apoptosis is mediated by the activation of caspase 8, via generation of truncated Bid, and thereafter release of cytochrome c. Interestingly, LTD(4) not only reverses the effects induced by inhibition of COX-2 but also reduces the apoptotic potential by lowering the basal level of caspase 8 activation and truncated Bid generation. PMID:12482325

Wikström, Katarina; Juhas, Maria; Sjölander, Anita

2003-04-01