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1

Esophageal cancer alters the expression of nuclear pore complex binding protein Hsc70 and eIF5A-1.  

PubMed

Nuclear pore complex (NPC) is the only corridor for macromolecules exchange between nucleus and cytoplasm. NPC and its components, nucleoporins, play important role in the diverse physiological processes including macromolecule exchange, chromosome segregation, apoptosis and gene expression. Recent reports also suggest involvement of nucleoporins in carcinogenesis. Applying proteomics, we analyzed expression pattern of the NPC components in a newly established esophageal cancer cell line from Persia (Iran), the high-risk region for esophageal cancer. Our results indicate overexpression of Hsc70 and downregulation of subunit alpha type-3 of proteasome, calpain small subunit 1, and eIF5A-1. Among these proteins, Hsc70 and eIF5A-1 are in direct interaction with NPC and involved in the nucleocytoplasmic exchange. Hsc70 plays a critical role as a chaperone in the formation of a cargo-receptor complex in nucleocytoplasmic transport. On the other hand, it is an NPC-associated protein that binds to nucleoporins and contributes in recycling of the nucleocytoplasmic transport receptors in mammals and affects transport of proteins between nucleus and cytoplasm. The other nuclear pore interacting protein: eIF5A-1 binds to the several nucleoporins and participates in nucleocytoplasmic transport. Altered expression of Hsc70 and eIF5A-1 may cause defects in nucleocytoplasmic transport and play a role in esophageal carcinogenesis. PMID:23539416

Moghanibashi, Mehdi; Rastgar Jazii, Ferdous; Soheili, Zahra-Soheila; Zare, Maryam; Karkhane, Aliasghar; Parivar, Kazem; Mohamadynejad, Parisa

2013-03-29

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.  

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

2011-08-18

4

Role of p38 and JNK MAPK signaling pathways and tumor suppressor p53 on induction of apoptosis in response to Ad-eIF5A1 in A549 lung cancer cells  

PubMed Central

Background The eukaryotic translation initiation factor 5A1 (eIF5A1) is a highly conserved protein involved in many cellular processes including cell division, translation, apoptosis, and inflammation. Induction of apoptosis is the only function of eIF5A1 that is known to be independent of post-translational hypusine modification. In the present study, we investigated the involvement of mitogen- and stress-activated protein kinases during apoptosis of A549 lung cancer cells infected with adenovirus expressing eIF5A1 or a mutant of eIF5A1 that cannot be hypusinated (eIF5A1K50A). Methods Using adenoviral-mediated transfection of human A549 lung cancer cells to over-express eIF5A1 and eIF5A1K50A, the mechanism by which unhypusinated eIF5A1 induces apoptosis was investigated by Western blotting, flow cytometry, and use of MAPK and p53 inhibitors. Results Phosphorylation of ERK, p38 MAPK, and JNK was observed in response to adenovirus-mediated over-expression of eIF5A1 or eIF5A1K50A, along with phosphorylation and stabilization of the p53 tumor suppressor protein. Synthetic inhibitors of p38 and JNK kinase activity, but not inhibitors of ERK1/2 or p53 activity, significantly inhibited apoptosis induced by Ad-eIF5A1. Importantly, normal lung cells were more resistant to apoptosis induced by eIF5A1 and eIF5A1K50A than A549 lung cancer cells. Conclusions Collectively these data indicate that p38 and JNK MAP kinase signaling are important for eIF5A1-induced cell death and that induction of apoptosis was not dependent on p53 activity.

2013-01-01

5

Promoting Active Involvement in Classrooms  

ERIC Educational Resources Information Center

|This article presents a rationale for using active involvement techniques, describes large- and small-group methods based on their documented effectiveness and applicability to K-12 classrooms, and illustrates their use. These approaches include ways of engaging students in large groups (e.g., unison responses, response cards, dry-erase boards,…

Conderman, Greg; Bresnahan, Val; Hedin, Laura

2012-01-01

6

Caspase activation is involved in chronic periodontitis.  

PubMed

Periodontitis, a common infectious disease, is initiated by various gram-negative bacteria and characterized by the destruction of the periodontal tissue. Here, we investigated the role of caspases, intracellular proteases that are the key mediators of apoptosis. We show that activation of caspase-3 and caspase-7 is considerably enhanced in gingival tissue from patients with periodontitis. We also demonstrate in in vitro experiments that various periodontopathic bacteria exert a direct growth-suppressing effect and, moreover, can trigger a host-mediated cytotoxic activity involving the CD95 death receptor. Our data suggest that caspase activation is a prominent feature in periodontitis-associated tissue injury. PMID:16213496

Bantel, Heike; Beikler, Thomas; Flemmig, Thomas F; Schulze-Osthoff, Klaus

2005-09-28

7

Moon Watch: A Parental-Involvement Homework Activity.  

ERIC Educational Resources Information Center

Presents the goals, philosophy, and methods of the SPLASH (Student-Parent Laboratories Achieving Science at Home) program. Describes an at-home, parental-involvement activity called Moon Watch in which students and their parents observe how the phases of the moon and the moon's position in the sky change over a two-week period. (WRM)

Rillero, Peter; Gonzalez-Jensen, Margarita; Moy, Tracy

2000-01-01

8

Involvement in 12-step activities and treatment outcomes.  

PubMed

This study addresses the relative importance of specific 12-step activities to recovery, and how treatment affects participation in those activities. Data were from a clinical trial testing a 12-step facilitation intervention called MAAEZ (Making AA [Alcohol Anonymous] Easier). Participants (N = 508) were recruited at treatment entry. Analyses examined 8 activities measured at baseline, 7 weeks, 6 months, and 12 months. 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. Contradicting research suggesting that meeting attendance contributes little beyond other 12-step activities, the current results highlight the importance of consistent meeting attendance and sponsorship in recovery. The results suggest a need for enhanced facilitation of key activities even in typical 12-step-oriented treatment. PMID:23327505

Zemore, Sarah E; Subbaraman, Meenakshi; Tonigan, J Scott

2013-01-01

9

A novel receptor involved in T-cell activation  

Microsoft Academic Search

OPTIMAL T-cell activation and T-cell expansion require triggering by T-cell antigen receptors and co-stimulatory signals provided by accessory cells1á¤-3. A major co-stimulatory pathway involves crosslinking the CD28 molecule on T cells by its ligands CD80 or CD86 expressed on antigen-presenting cells4á¤-7. But recent studies8,9 on CD28-deficient mice have indicated that CD28 is not required for all T-cell responses and that

Benjamin G. Cocks; Chia-Chun J. Chang; Hans Yssel; Jan E. de Vries; Gregorio Aversa

1995-01-01

10

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

2006-07-13

11

Pontine respiratory activity involved in inspiratory/expiratory phase transition  

PubMed Central

Control of the timing of the inspiratory/expiratory (IE) phase transition is a hallmark of respiratory pattern formation. In principle, sensory feedback from pulmonary stretch receptors (Breuer–Hering reflex, BHR) is seen as the major controller for the IE phase transition, while pontine-based control of IE phase transition by both the pontine Kölliker–Fuse nucleus (KF) and parabrachial complex is seen as a secondary or backup mechanism. However, previous studies have shown that the BHR can habituate in vivo. Thus, habituation reduces sensory feedback, so the role of the pons, and specifically the KF, for IE phase transition may increase dramatically. Pontine-mediated control of the IE phase transition is not completely understood. In the present review, we discuss existing models for ponto-medullary interaction that may be involved in the control of inspiratory duration and IE transition. We also present intracellular recordings of pontine respiratory units derived from an in situ intra-arterially perfused brainstem preparation of rats. With the absence of lung inflation, this preparation generates a normal respiratory pattern and many of the recorded pontine units demonstrated phasic respiratory-related activity. The analysis of changes in membrane potentials of pontine respiratory neurons has allowed us to propose a number of pontine-medullary interactions not considered before. The involvement of these putative interactions in pontine-mediated control of IE phase transitions is discussed.

Morschel, Michael; Dutschmann, Mathias

2009-01-01

12

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

13

Biological activity and potential remediation involving geotextile landfill leachate filters  

SciTech Connect

The paper presents the results of a biological growth study in geotextile filters used in landfill leachate collection systems. After reviewing the first year's activity, a completely new experimental approach has been taken. Using 100 mm diameter columns for the experimental incubation and flow systems, the effects of six landfill leachates are evaluated. Aerobic and anaerobic states, four different geotextiles, and soil/no soil conditions above the geotextiles are involved in the testing program. The results in 96 individual test columns. Flow data is measured regularly, and over the first six months of evaluation certain trends were observed. For two of the landfill leachates, backflushing has been attempted so as to reinstitute flow. The procedure works well for the geotextile alone while not as well for the geotextile/soil columns. The exception is the nonwoven heat set geotextile. All tests are still ongoing and will be dismantled and further investigated at the end of 12 months exposure time. The experimental setup and procedure has been written up as a tentative ASTM test method and is currently in task group review.

Koerner, G.R.; Koerner, R.M.

1992-01-01

14

[Health management of Saipem workers with projects involving abroad activities].  

PubMed

In remote areas and in developing countries, where adequate health-care structures are few and sparse, Occupational Medicine contributes to guaranteeing workers' health. Companies like Saipem, involved in activities that are carried out in remote, inhospitable areas must ensure the safety and guarantee the health conditions of workers in relation to the risk factors connected with the job as well as with the environment in which it is performed. In such situations, Occupational Medicine addresses both the health aspects of the workplace and of the community, and is the pivot around which revolves the health-care support of workers employed abroad in the sense of protection and enhancement of health. The risks connected with work abroad are of three main types: 1) job-related risks; 2) risks connected with the environment; 3) risks related to the organization of work and the changes in the worker's daily life. The job-related risks are similar to those connected with analogous jobs performed elsewhere. The risks connected with the environment are related to adverse climatic conditions, extreme temperatures and unknown and often dangerous flora and fauna. The occupational physician is called upon to assess the suitability of workers for jobs that are based in remote areas. The main clinical conditions that can prevent issue of the Medical Fitness Certificate to workers for long-stay jobs abroad are discussed. PMID:18409664

Nicosia, V; De Sanctis, S; Mika, F; Consentino, M; Mascheroni, G

15

15 CFR 712.2 - Restrictions on activities involving Schedule 1 chemicals.  

Code of Federal Regulations, 2013 CFR

...on activities involving Schedule 1 chemicals. 712.2 Section 712.2 Commerce...SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 1 CHEMICALS § 712.2 Restrictions on...

2013-01-01

16

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

17

Overview of Corps of Engineers waste containment activities involving geosynthetics  

Microsoft Academic Search

Containment has proven to be a viable option for remediating many hazardous waste sites. The US Army Corps of Engineers (COE) has been involved in the design and\\/or construction of more than 40 landfill remediation projects for Superfund projects and military installations since 1982. Geosynthetics have played a major role in the success of these projects. This paper focuses on

David L. Jaros

1996-01-01

18

Motivating teachers and their involvement in space activities  

Microsoft Academic Search

It is essential that our young people are active participants in the world of space. This will only be achieved if their teachers are both well-informed and active participants themselves. A large number of teachers are currently switched on to space-related matters because of their need to use data from past and current missions. These teachers and consequently their students

Annette Temple

1997-01-01

19

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

20

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

21

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

Microsoft Academic Search

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 involvement as a social setting variable and a differential factor. Certain activities

Siu Kwong Wong

2005-01-01

22

Instructional, Context, and Individual Differences in Pupil Involvement in Learning Activity.  

ERIC Educational Resources Information Center

Assuming that pupil involvement in academic learning activities (involved time) is a behavioral indicator of pupil learning, this study examined two context variables (subject area, day of the week) one instructional variable (activity format) and one pupil variable (previous achievement growth) in relation to pupil involved time. Individual pupil…

Cornbleth, Catherine; Korth, Willard

23

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

24

Involvement of platelet activation in experimental osteonecrosis in rabbits  

PubMed Central

Osteonecrosis (ON) was produced experimentally in rabbits by intravenous injection of platelet activating factor (PAF) in combination with lipopolysaccharides (LPS) on two occasions separated by a week-long interval. Eleven of 15 rabbits (73%), with administration of both LPS (50 µg/kg) and PAF (10 µg/kg), exhibited microcirculatory injuries including extravasation of erythrocytes into sinusoidal spaces and formation of microthrombi in arterioles near regions of erythrocyte extravasation. Seven of 15 rabbits (47%), which received both LPS (50 µg/kg) and PAF (10 µg/kg), exhibited necrosis of trabeculae and 8 of 15 (53%) exhibited bone marrow necrosis. In addition, PAF receptor antagonist (0.3 and 3.0 mg/kg) significantly reduced the incidence of trabecular necrosis (0%) in this model. The findings of the present study suggest that platelet activation may play an important role in inducible ON, and that suppression of platelet activation may contribute prevention of ON.

MASUHARA, KENSAKU; NAKATA, KATSUYA; YAMASAKI, SATOSHI; MIKI, HIDENOBU; YOSHIKAWA, HIDEKI

2001-01-01

25

Activation and Involvement of Ral GTPases in Colorectal Cancer  

PubMed Central

Current approaches to block KRAS oncogene function focus on inhibition of K-Ras downstream effector signaling. We evaluated the anti-tumor activity of selumetinib (AZD6244, ARRY-142886), a potent and selective MEK1/2 inhibitor, on a panel of colorectal carcinoma (CRC) cells and found no inhibition of KRAS mutant CRC cell anchorage-independent growth. While AKT activity was elevated in KRAS mutant cells, and PI3K inhibition did impair the growth of MEK inhibitor-insensitive CRC cell lines, concurrent treatment with selumetinib did not provide additional anti-tumor activity. Therefore, we speculated that inhibition of the Ral guanine exchange factor (RalGEF) effector pathway may be a more effective approach for blocking CRC growth. RalGEFs are activators of the related RalA and RalB small GTPases and we found activation of both in CRC cell lines and patient tumors. Interfering RNA stable suppression of RalA expression reduced CRC tumor cell anchorage-independent growth, but surprisingly, stable suppression of RalB greatly enhanced soft agar colony size and formation frequency. Despite their opposing activities, both RalA and RalB regulation of anchorage-independent growth required interaction with RalBP1/RLIP76 and components of the exocyst complex. Interestingly, RalA interaction with the Exo84 but not Sec5 exocyst component was necessary for supporting anchorage-independent growth, whereas RalB interaction with Sec5 but not Exo84 was necessary for inhibition of anchorage-independent growth. We suggest that anti-RalA-selective therapies may provide an effective approach for KRAS mutant CRC.

Martin, Timothy D.; Samuel, Jonathan C.; Routh, Elizabeth D.; Der, Channing J.; Yeh, Jen Jen

2010-01-01

26

Involvement of Toso in activation of monocytes, macrophages, and granulocytes  

PubMed Central

Rapid activation of immune responses is necessary for antibacterial defense, but excessive immune activation can result in life-threatening septic shock. Understanding how these processes are balanced may provide novel therapeutic potential in treating inflammatory disease. Fc receptors are crucial for innate immune activation. However, the role of the putative Fc receptor for IgM, known as Toso/Faim3, has to this point been unclear. In this study, we generated Toso-deficient mice and used them to uncover a critical regulatory function of Toso in innate immune activation. Development of innate immune cells was intact in the absence of Toso, but Toso-deficient neutrophils exhibited more reactive oxygen species production and reduced phagocytosis of pathogens compared with controls. Cytokine production was also decreased in Toso?/? mice compared with WT animals, rendering them resistant to septic shock induced by lipopolysaccharide. However, Toso?/? mice also displayed limited cytokine production after infection with the bacterium Listeria monocytogenes that was correlated with elevated presence of Listeria throughout the body. Accordingly, Toso?/? mice succumbed to infections of L. monocytogenes, whereas WT mice successfully eliminated the infection. Taken together, our data reveal Toso to be a unique regulator of innate immune responses during bacterial infection and septic shock.

Lang, Karl S.; Lang, Philipp A.; Meryk, Andreas; Pandyra, Aleksandra A.; Boucher, Louis-Martin; Pozdeev, Vitaly I.; Tusche, Michael W.; Gothert, Joachim R.; Haight, Jillian; Wakeham, Andrew; You-Ten, Annick J.; McIlwain, David R.; Merches, Katja; Khairnar, Vishal; Recher, Mike; Nolan, Garry P.; Hitoshi, Yasumichi; Funkner, Pauline; Navarini, Alexander A.; Verschoor, Admar; Shaabani, Namir; Honke, Nadine; Penn, Linda Z.; Ohashi, Pamela S.; Haussinger, Dieter; Lee, Kyeong-Hee; Mak, Tak W.

2013-01-01

27

Social Work with Religious Volunteers: Activating and Sustaining Community Involvement  

ERIC Educational Resources Information Center

|Social workers in diverse community practice settings recruit and work with volunteers from religious congregations. This article reports findings from two surveys: 7,405 congregants in 35 Protestant congregations, including 2,570 who were actively volunteering, and a follow-up survey of 946 volunteers. It compares characteristics of congregation…

Garland, Diana R.; Myers, Dennis M.; Wolfer, Terry A.

2008-01-01

28

Involvement of hypothalamic AMP-activated protein kinase in leptin-induced sympathetic nerve activation.  

PubMed

In mammals, leptin released from the white adipose tissue acts on the central nervous system to control feeding behavior, cardiovascular function, and energy metabolism. Central leptin activates sympathetic nerves that innervate the kidney, adipose tissue, and some abdominal organs in rats. AMP-activated protein kinase (AMPK) is essential in the intracellular signaling pathway involving the activation of leptin receptors (ObRb). We investigated the potential of AMPK?2 in the sympathetic effects of leptin using in vivo siRNA injection to knockdown AMPK?2 in rats, to produce reduced hypothalamic AMPK?2 expression. Leptin effects on body weight, food intake, and blood FFA levels were eliminated in AMPK?2 siRNA-treated rats. Leptin-evoked enhancements of the sympathetic nerve outflows to the kidney, brown and white adipose tissues were attenuated in AMPK?2 siRNA-treated rats. To check whether AMPK?2 was specific to sympathetic changes induced by leptin, we examined the effects of injecting MT-II, a melanocortin-3 and -4 receptor agonist, on the sympathetic nerve outflows to the kidney and adipose tissue. MT-II-induced sympatho-excitation in the kidney was unchanged in AMPK?2 siRNA-treated rats. However, responses of neural activities involving adipose tissue to MT-II were attenuated in AMPK?2 siRNA-treated rats. These results suggest that hypothalamic AMPK?2 is involved not only in appetite and body weight regulation but also in the regulation of sympathetic nerve discharges to the kidney and adipose tissue. Thus, AMPK might function not only as an energy sensor, but as a key molecule in the cardiovascular, thermogenic, and lipolytic effects of leptin through the sympathetic nervous system. PMID:23418591

Tanida, Mamoru; Yamamoto, Naoki; Shibamoto, Toshishige; Rahmouni, Kamal

2013-02-13

29

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

30

Dopamine is involved in food-anticipatory activity in mice.  

PubMed

When food is available during a restricted and predictable time of the day, mammals exhibit food-anticipatory activity (FAA), an increase in locomotor activity preceding the presentation of food. Although many studies have attempted to locate the food-entrainable circadian oscillator in the central nervous system, the pathways that mediate food entrainment are a matter of controversy. The present study was designed to determine the role of dopaminergic and histaminergic systems on FAA. Mice were given access to food for 2 h (ZT12-ZT14), and FAA was defined as the locomotor activity that occurred 2 h before the availability of food. Dopamine D(1) receptor (R), D(2)R, and histamine H(1)R-specific antagonists were used to clarify the role of dopamine and histamine receptors in FAA induced by food restriction (FR). FAA was monitored by infrared locomotor activity sensors. Mice were sacrificed at ZT12 on the 14th day of FR, and monoamine concentrations were determined by high-performance liquid chromatography coupled to electrochemical detection (HPLC-ECD). The results showed that pretreatment with the D(1)R antagonist SCH23390 at 1, 3, or 10 µg/kg significantly reduced FAA by 19% (p < 0.05), 26% (p < 0.05), or 19% (p < 0.01), respectively, and the D(2)R antagonist raclopride at 22, 67, or 200 µg/kg significantly reduced FAA by 16% (p < 0.05), 36% (p < 0.01), or 41% (p < 0.01), respectively, as compared with vehicle control. Moreover, coadministration of SCH23390 (10 µg/kg) and raclopride (200 µg/kg) synergistically inhibited FAA by 57% (p < 0.01) as compared with vehicle control. Consistently, the levels of dopamine and its metabolites in the striatum and midbrain were significantly increased during FAA, even with the pretreatment of D(1)R and D(2)R antagonists. However, pretreatment with pyrilamine at 2.5, 5, or 10 mg/kg did not significantly reduce FAA, although it reduced the locomotor activity during the dark period in ad libitum mice. These results strongly indicate that the dopaminergic system plays an essential role in the FAA in mice. PMID:23010662

Liu, Yuan-Yuan; Liu, Tian-Ya; Qu, Wei-Min; Hong, Zong-Yuan; Urade, Yoshihiro; Huang, Zhi-Li

2012-10-01

31

Organized activity involvement, depressive symptoms, and social adjustment in adolescents: ethnicity and socioeconomic status as moderators.  

PubMed

The current cross-sectional study investigated the links between various dimensions of organized activity involvement and depressive symptoms, loneliness, and peer victimization in an ethnically and economically diverse sample of adolescents (N = 152; 58% female). Results indicate that adolescents who were involved in organized activities for more years also reported lower levels of loneliness. There was evidence of diminishing returns when adolescents were very highly involved in organized activities; those who were either under- or over-involved reported the highest levels of depressive symptoms. Conversely, findings indicate that adolescents who participated in a narrow or wide range of activity contexts reported the lowest levels of depressive symptoms. In addition, results suggested that the relation between organized activity involvement and adjustment differs among adolescents from diverse ethnic and socioeconomic backgrounds. Findings from the current study also underscore the importance of considering multiple indices of activity involvement when assessing its association with adjustment. PMID:19669899

Randall, Edin T; Bohnert, Amy M

2009-05-28

32

Organoselenium improves memory decline in mice: involvement of acetylcholinesterase activity.  

PubMed

The present study was designed to investigate the possible neuroprotective effect of p,p'-methoxyl-diphenyl diselenide [(MeOPhSe)(2)] in a model of sporadic dementia of Alzheimer's type (SDAT) induced by intracerebroventricular (i.c.v.) injection of streptozotocin (STZ) in mice. Mice were divided into four groups: (I) control, (II) (MeOPhSe)(2), (III) STZ, and (IV) (MeOPhSe)(2)+STZ. Mice were exposed to (MeOPhSe)(2) (25mg/kg, by gavage) and STZ (2mul of 2.5mg/ml solution; i.c.v.) or vehicles. 48 after that the exposure was repeated. Learning and memory were assessed with the step-down-type passive-avoidance (SDPA) and Morris water-maze (MWM) tests at the days 5-6 and 6-9, respectively. At the end of the experimental protocol animals were euthanized and cerebral cortex was removed for acetylcholinesterase (AChE) activity assay. Our results confirmed that i.c.v. STZ caused learning and memory deficits in mice, which were verified using the MWM and SDPA tasks. Furthermore, this study showed that AChE activity was increased in mice that received i.c.v. STZ. The most important findings of the present study are that (MeOPhSe)(2) was able to reverse the learning and memory impairments induced by STZ, and to protect against the increase in AChE activity. All these findings support the neuroprotective role of (MeOPhSe)(2) in a mice model of SDAT induced by i.c.v. STZ. PMID:20122991

Pinton, Simone; da Rocha, Juliana Trevisan; Zeni, Gilson; Nogueira, Cristina Wayne

2010-02-01

33

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

34

Antibacterial activity of Thai herbal extracts on acne involved microorganism.  

PubMed

Ethyl acetate and methanol extracts of 18 Thai medicinal plants were investigated for their antibacterial activity against Propionibacterium acnes, Stapylococcus aureus, and S. epidermidis. Thirteen plant extracts were capable of inhibiting the growth of P. acnes and S. epidermidis, while 14 plant extracts exhibited an inhibitory effect on S. aureus. Based on the broth dilution method, the ethyl acetate extract of Alpinia galanga (L.) Wild. (Zingiberaceae) rhizome showed the strongest antibacterial effect against P. acnes, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.0 and 312.0 microg/mL, respectively. On the basis of bioassay-guided purification, the ethyl acetate extract was isolated to afford the antibacterial active compound, which was identified as 1'-acetoxychavicol acetate (1'-ACA). 1'-ACA had a strong inhibitory effect on P. acnes with MIC and MBC values of 62.0 and 250.0 microg/mL, respectively. Thus, 1'-ACA was used as an indicative marker for standardization of A. galanga extract using high performance liquid chromatography. These results suggest that A. galanga extract could be an interesting agent for further studies on an alternative treatment of acne. PMID:20645714

Niyomkam, P; Kaewbumrung, S; Kaewnpparat, S; Panichayupakaranant, P

2010-04-01

35

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

36

Anticancer activity of metal complexes: involvement of redox processes.  

PubMed

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. PMID:21275772

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

2011-05-11

37

Urokinase-type plasminogen activator and arthritis progression: role in systemic disease with immune complex involvement  

Microsoft Academic Search

INTRODUCTION: Urokinase-type plasminogen activator (u-PA) has been implicated in fibrinolysis, cell migration, latent cytokine activation, cell activation, T-cell activation, and tissue remodeling, all of which are involved in the development of rheumatoid arthritis. Previously, u-PA has been reported to play a protective role in monoarticular arthritis models involving mBSA as the antigen, but a deleterious role in the systemic polyarticular

Andrew D Cook; Christine M De Nardo; Emma L Braine; Amanda L Turner; Ross Vlahos; S Kaye Beckman; Jason C Lenzo; John A Hamilton

2010-01-01

38

Ego Strength Development of Adolescents Involved in Adult-Sponsored Structured Activities.  

ERIC Educational Resources Information Center

|A psychosocial conception of ego strengths is presented in relation to adolescent involvement in adult-sponsored structured youth activities. Five-hundred and seventeen high school students completed measures on their involvement in structured activities and on 8 ego strengths. Gender, age, and SES were controlled in a MANCOVA procedure and it…

Markstrom, Carol A.; Li, Xaioming; Blackshire, Shana L.; Wilfong, Juanita J.

2005-01-01

39

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

40

Organized Activity Involvement, Depressive Symptoms, and Social Adjustment in Adolescents: Ethnicity and Socioeconomic Status as Moderators  

ERIC Educational Resources Information Center

|The current cross-sectional study investigated the links between various dimensions of organized activity involvement and depressive symptoms, loneliness, and peer victimization in an ethnically and economically diverse sample of adolescents (N = 152; 58% female). Results indicate that adolescents who were involved in organized activities for…

Randall, Edin T.; Bohnert, Amy M.

2009-01-01

41

Capturing Unique Dimensions of Youth Organized Activity Involvement: Theoretical and Methodological Considerations  

ERIC Educational Resources Information Center

|Despite increased focus on the effects of organized activities on youth development, there is currently no consensus about the best way to assess various dimensions of involvement. This article explores the complexities of assessing involvement and focuses specifically on the following organized activity dimensions: (a) breadth, (b) intensity,…

Bohnert, Amy; Fredricks, Jennifer; Randall, Edin

2010-01-01

42

Breadth and Intensity: Salient, Separable, and Developmentally Significant Dimensions of Structured Youth Activity Involvement  

ERIC Educational Resources Information Center

|In recent years, an impressive volume of evidence has accumulated demonstrating that youth involvement in structured, organized activities (e.g. school sports, community clubs) may facilitate positive youth development. We present a theory-based framework for studying structured activity involvement (SAI) as a context for positive youth…

Busseri, Michael A.; Rose-Krasnor, Linda

2009-01-01

43

A Longitudinal Study of Breadth and Intensity of Activity Involvement and the Transition to University  

ERIC Educational Resources Information Center

|We examined prospective relations between activity involvement and successful transitioning to university. A sample of 656 students from 6 Canadian universities completed questionnaires before beginning university and at the end of their first year. Breadth (number of different activity domains) and intensity (mean frequency) of activity

Busseri, Michael A.; Rose-Krasnor, Linda; Pancer, S. Mark; Pratt, Michael W.; Adams, Gerald R.; Birnie-Lefcovitch, Shelly; Polivy, Janet; Wintre, Maxine Gallander

2011-01-01

44

Curcumin-induced recovery from hepatic injury involves induction of apoptosis of activated hepatic stellate cells  

Microsoft Academic Search

Hepatic stellate cells (HSCs) undergo activation and transdifferentiation to myofibroblast like cells in liver injury, leading to liver fibrosis. During recovery from injury, activated HSCs may either revert back to quiescent state or undergo apoptosis or both. In the present study, we have examined whether recovery from hepatic injury involves apoptosis of activated HSCs and tested whether curcumin (the yellow

S Priya; P R Sudhakaran

45

Recent significant U.S. court cases involving forensic activation analysis  

Microsoft Academic Search

The first U.S. court case involving forensic activation analysis (FAA) took place in March of 1964. During the subsequent\\u000a five years, many other cases involving FAA results went to trial in the U.S., but these seldom involved any serious attempts\\u000a by the defense to challenge the FAA testimony presented by the prosecution. During roughly the last three years, however,\\u000a there

V. P. Guinn

1973-01-01

46

International Carbon Dioxide-Related Activities: The International Organizations Involved and US Bilateral Arrangements.  

National Technical Information Service (NTIS)

The issue of increasing carbon dioxide in the atmosphere, its measurement and possible impact, is one of global dimensions. Several organizations with international membership are actively involved in efforts to resolve the unanswered questions surroundin...

R. Dougher

1983-01-01

47

Organized Activity Involvement, Depressive Symptoms, and Social Adjustment in Adolescents: Ethnicity and Socioeconomic Status as Moderators  

Microsoft Academic Search

The current cross-sectional study investigated the links between various dimensions of organized activity involvement and\\u000a depressive symptoms, loneliness, and peer victimization in an ethnically and economically diverse sample of adolescents (N = 152; 58% female). Results indicate that adolescents who were involved in organized activities for more years also reported\\u000a lower levels of loneliness. There was evidence of diminishing returns when adolescents

Edin T. Randall; Amy M. Bohnert

2009-01-01

48

New Zealand children's involvement in home activities that carry a burn or scald risk  

PubMed Central

Objectives—The self reported involvement of elementary schoolchildren from Auckland, New Zealand was measured for home activities that carry a burn or scald risk. Method—A survey was conducted with 421 children aged 7–13 years. The survey asked children whether they carried out specific home activities involving hot water, fire, or appliances that carry a burn risk. It also measured their knowledge of the three basic fire safety messages taught to New Zealand schoolchildren by the fire service. Results—The results showed that although involvement levels increased with age, the majority of even the youngest children reported carrying out a number of the risky activities, such as preparing hot drinks, running their own baths, or using a microwave without help. No gender differences were found in the number of risky activities engaged in. Significant ethnic differences were found, with higher risk involvement by indigenous Maori and children of Pacific Island descent than children of European or Asian descent. Each of the three fire safety messages were correctly identified by between 79%–91% of the children. Conclusions—Investigation of children's involvement in household activities that carry an injury risk may help in the design of prevention strategies, including school based education. Prevention efforts need to acknowledge the ages at which children begin to undertake specific household tasks, including those that involve care for younger siblings, and be attuned to the needs of different ethnic groups.

Harre, N.; Field, J.; Polzer-Debruyne, A.

1998-01-01

49

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

2008-01-01

50

Extracurricular activity involvement is associated with adolescent suicidality through school belongingness  

Microsoft Academic Search

Adolescent sports participants report lower rates of suicidality compared with sports nonparticipants. Few studies have investigated whether this pattern holds for involvement in other types of extracurricular activities, in younger samples, or the mechanisms of these associations. This study investigated the mediating role of school belongingness on the association between types of extracurricular activities and suicidality in developmental age groups

Andrea D. Mata; Manfred H. M. van Dulmen; Katherine C. Schinka; Monica H. Swahn; Robert M. Bossarte; Daniel J. Flannery

2012-01-01

51

Context Factors and Individual Differences in Pupil Involvement in Learning Activity.  

ERIC Educational Resources Information Center

Three variables: subject area, day of the week, and academic activity, were examined to determine whether pupil involvement in academic learning activities is an indicator of pupil learning. Differences were found in each variable, implying that more effective use of allocated instruction time will increase academic achievement. (JD)

Cornbleth, Catherine; Korth, Willard

1980-01-01

52

Understanding Threshold Effects of Organized Activity Involvement in Adolescents: Sex and Family Income as Moderators  

ERIC Educational Resources Information Center

|The current study examined the curvilinear links between involvement in organized activities (OA) and sport activities specifically and various indicators of psychological and social development. Participants included 150 9th and 10th graders (57% females) from an urban, selective-enrollment high school. Eligibility for admission is based on city…

Randall, Edin T.; Bohnert, Amy M.

2012-01-01

53

International carbon dioxide-related activities: the international organizations involved and US bilateral arrangements  

Microsoft Academic Search

The issue of increasing carbon dioxide in the atmosphere, its measurement and possible impact, is one of global dimensions. Several organizations with international membership are actively involved in efforts to resolve the unanswered questions surrounding this issue. This paper describes broadly these international organizations and the type of COâ-related activities they conduct and outlines the COâ research work conducted through

Dougher

1983-01-01

54

Understanding threshold effects of organized activity involvement in adolescents: Sex and family income as moderators  

Microsoft Academic Search

The current study examined the curvilinear links between involvement in organized activities (OA) and sport activities specifically and various indicators of psychological and social development. Participants included 150 9th and 10th graders (57% females) from an urban, selective-enrollment high school. Eligibility for admission is based on city residence, high GPA, and high scores on standardized tests and an admission exam.

Edin T. Randall; Amy M. Bohnert

55

The Psychological Impact of Industrial Strikes: Does Involvement in Union Activity during Strikes make a Difference?  

Microsoft Academic Search

The current study investigated the psychological impact of a United Steelworkers of America strike on the steelworkers involved, and the relationship between psychological well-being and individuals' levels of involvement in union activity during the strike. Three hundred and fifty-one steelworkers (302 `strikers' and 49 `non-strikers') completed surveys measuring a range of demographic and psychological well-being variables. Strikers, compared to non-strikers,

Jane L. Fowler; Amanda J. Gudmundsson; Leanne M. Whicker

2009-01-01

56

15 CFR 712.1 - Round to zero rule that applies to activities involving Schedule 1 chemicals.  

Code of Federal Regulations, 2013 CFR

...to activities involving Schedule 1 chemicals. 712.1 Section 712.1 Commerce...SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS ACTIVITIES INVOLVING SCHEDULE 1 CHEMICALS § 712.1 Round to zero...

2013-01-01

57

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

Code of Federal Regulations, 2013 CFR

...aliens involved in serious criminal activity who have asserted immunity from prosecution. [Reserved] 40.25 Section 40.25...aliens involved in serious criminal activity who have asserted immunity from prosecution....

2013-04-01

58

Curcumin-induced recovery from hepatic injury involves induction of apoptosis of activated hepatic stellate cells.  

PubMed

Hepatic stellate cells (HSCs) undergo activation and transdifferentiation to myofibroblast like cells in liver injury, leading to liver fibrosis. During recovery from injury, activated HSCs may either revert back to quiescent state or undergo apoptosis or both. In the present study, we have examined whether recovery from hepatic injury involves apoptosis of activated HSCs and tested whether curcumin (the yellow pigment from Curcuma longa Linn.) promotes recovery from hepatic injury by inducing apoptosis of these cells. Hepatic injury was induced by CCl4 and apoptosis was studied in HSCs isolated from liver by MTT assay, DNA fragmentation, and DAPI and annexin staining. Hepatic recovery was assessed by measuring hepatic marker activities, such as serum GOT, GPT and protein. Hepatic recovery occurred within 4 weeks after inducing injury in untreated control, whereas curcumin treatment caused hepatic recovery within 2 weeks, as evidenced by the reduction of hepatic marker activities to near normal levels. HSCs isolated from liver of animals treated with curcumin showed maximum apoptotic marker activities in 2nd week, whereas in HSCs from untreated control recovering from injury, maximum apoptosis was observed in 4th week. Induction of apoptosis in vivo during hepatic recovery was also suggested by increase in caspase-3 activity. Treatment of isolated HSCs in culture with curcumin caused apoptosis during later stages confirming that curcumin induced apoptosis of activated HSCs and not in unactivated quiescent HSCs. These results suggested that hepatoprotective effect of curcumin causing recovery from injury involved apoptosis of activated HSCs. PMID:19069843

Priya, S; Sudhakaran, P R

2008-10-01

59

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

60

Interstitial Collagenase Is Expressed by Keratinocytes That Are Actively Involved in Reepithelialization in Blistering Skin Diseases  

Microsoft Academic Search

Migrating keratinocytes actively involved in reepithelialization in dermal wounds acquire a collagenolytic phenotype upon contact with the dermal matrix. To determine whether this phenotype is associated with repair in other forms of wounds, we assessed collagenase expression in 50 specimens representing a variety of blistering skin diseases, including subtypes of epidermolysis bullosa, porphyria cutanea tarda, bullous pemphigoid, pemphigus, transient acantholytic

Ulpu K. Saarialho-Kere; Maarit Vaalamo; Kristiina Airola; Kirsti-Maria Niemi; Aarne I. Oikarinen; William C. Parks

1995-01-01

61

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

62

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

63

Beyond the Classroom: Involving Students with Disabilities in Extracurricular Activities at Levy Middle School.  

ERIC Educational Resources Information Center

Six students in a special education classroom at Levy Middle School (Syracuse, New York) became involved in a variety of after-school activities with nondisabled students. The students participated in the school computer club, cross-country skiing, volleyball, stage crew, intramural basketball, the Spanish Club, and after-school programs at two…

Walker, Pam; And Others

64

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

Microsoft Academic Search

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

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

2007-01-01

65

Regrouping: organized activity involvement and social adjustment across the transition to high school.  

PubMed

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 changes and OAs may provide an important setting for establishing and maintaining peer relationships during this tumultuous time. This study included 151 8th grade U.S. students (58% male) who were assessed across the transition to high school (spring of 8th and 9th grade). Continuous involvement in academic activities across the transition and becoming involved (i.e., initiation) in community/service activities following the transition was associated with fewer depressive symptoms in the spring of 9th grade. Continuous involvement in sports and initiation of academic activities was associated with having more friendships. In addition, links between OAs and loneliness were only evident among females. There appear to be significant social benefits for OA involvement. PMID:23766096

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

2013-01-01

66

Structural model of employee involvement in skill development activity: The role of individual differences  

Microsoft Academic Search

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 tested both mediated and direct effects of the variables. The sequence of relationships observed in the

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

2008-01-01

67

An Active Self-Determination Technique: Involving Students in Effective Career Planning.  

ERIC Educational Resources Information Center

|This paper discusses creating story boards to help students with disabilities to develop effective career plans. It describes storyboarding as a technique for project planning which requires active involvement of both hemispheres of the brain. A group of 6-8 people, including students, teachers, counselors, and vocational rehabilitation…

Denison, Grace L.

68

Beyond Participation: The Association between School Extracurricular Activities and Involvement in Violence across Generations of Immigration  

ERIC Educational Resources Information Center

Participation in extracurricular activities is purported to protect the broad spectrum of youth from a host of behavioral risks. Yet, empirical research on the extent to which this assumption holds for involvement in violence by immigrant youth is limited. Thus, using data for 13,236 (51.8% female) adolescents from the National Longitudinal Study…

Jiang, Xin; Peterson, Ruth D.

2012-01-01

69

INVOLVEMENT OF MICRORNAS IN EMBRYONIC GENOME ACTIVATION AS SHOWN BY DICER EXPRESSION IN RAINBOW TROUT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Most maternal transcripts including many housekeeping genes are degraded at or around embryonic genome activation as evidenced by our initial studies. This degradation appears to be global but highly regulated. MicroRNAs are naturally occurring small (19-24bp) RNAs that are shown to be involved in m...

70

Idle Hands and Empty Pockets?: Youth Involvement in Extracurricular Activities, Social Capital, and Economic Status  

ERIC Educational Resources Information Center

|Using data from the Survey of Adults and Youth, the authors examine the effect of economic status on youths' involvement in both school- and nonschool-related extracurricular activities. Specifically, they assess the association between four alternative measures of economic status--recipiency of food stamps, Aid to Families with Dependent…

White, Amanda M.; Gager, Constance T.

2007-01-01

71

Active serine involved in the stabilization of the active site loop in the Humicola lanuginosa lipase.  

PubMed

We have investigated the binding properties of and dynamics in Humicola lanuginosa lipase (Hll) and the inactive mutant S146A (active Ser146 substituted with Ala) using fluorescence spectroscopy and molecular dynamics simulations, respectively. Hll and S146A show significantly different binding behavior for phosphatidylcholine (PC) and phosphatidylglycerol (PG) liposomes. Generally, higher binding affinity is observed for Hll than the S146A mutant. Furthermore, depending on the matrix, the addition of the transition state analogue benzene boronic acid increases the binding affinity of S146A, whereas only small changes are observed for Hll suggesting that the active site lid in the latter opens more easily and hence more lipase molecules are bound to the liposomes. These observations are in agreement with molecular dynamics simulations and subsequent essential dynamics analyses. The results reveal that the hinges of the active site lid are more flexible in the wild-type Hll than in S146A. In contrast, larger fluctuations are observed in the middle region of the active site loop in S146A than in Hll. These findings reveal that the single mutation (S146A) of the active site serine leads to substantial conformational alterations in the H. lanuginosa lipase and different binding affinities. PMID:9730809

Peters, G H; Svendsen, A; Langberg, H; Vind, J; Patkar, S A; Toxvaerd, S; Kinnunen, P K

1998-09-01

72

Involvement of Signaling Molecules on Na+/H+ Exchanger-1 Activity in Human Monocytes  

PubMed Central

Background: Sodium/hydrogen exchanger-1 (NHE-1) contributes to maintaining intracellular pH (pHi). We assessed the effect of glucose, insulin, leptin and adrenaline on NHE-1 activity in human monocytes in vitro. These cells play a role in atherogenesis and disturbances in the hormones evaluated are associated with obesity and diabetes. Methods and Results: Monocytes were isolated from 16 healthy obese and 10 lean healthy subjects. NHE-1 activity was estimated by measuring pHi with a fluorescent dye. pHi was assessed pre- and post-incubation with glucose, insulin, leptin and adrenaline. Experiments were repeated after adding a NHE-1 inhibitor (cariporide) or an inhibitor of protein kinase C (PKC), nitric oxide synthase (NOS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, phosphoinositide 3-kinases (PI3K) or actin polymerization. Within the whole study population, glucose enhanced NHE-1 activity by a processes involving PKC, NOS, PI3K and actin polymerization (p = 0.0006 to 0.01). Insulin-mediated activation of NHE-1 (p = <0.0001 to 0.02) required the classical isoforms of PKC, NOS, NADPH oxidase and PI3K. Leptin increased NHE-1 activity (p = 0.0004 to 0.04) through the involvement of PKC and actin polymerization. Adrenaline activated NHE-1 (p = <0.0001 to 0.01) by a process involving the classical isoforms of PKC, NOS and actin polymerization. There were also some differences in responses when lean and obese subjects were compared. Incubation with cariporide attenuated the observed increase in NHE-1 activity. Conclusions: Selective inhibition of NHE-1 in monocytes could become a target for drug action in atherosclerotic vascular disease.

Sarigianni, Maria; Tsapas, Apostolos; Mikhailidis, Dimitri P; Kaloyianni, Martha; Koliakos, George; Paletas, Konstantinos

2010-01-01

73

Understanding threshold effects of organized activity involvement in adolescents: sex and family income as moderators.  

PubMed

The current study examined the curvilinear links between involvement in organized activities (OA) and sport activities specifically and various indicators of psychological and social development. Participants included 150 9th and 10th graders (57% females) from an urban, selective-enrollment high school. Eligibility for admission is based on city residence, high GPA, and high scores on standardized tests and an admission exam. Findings indicated that benefits of OA involvement leveled off at approximately 5-7 h/week, with diminishing returns for adolescents participating in more than 10 h/week. Results also suggest that OA involvement uniquely impacts male and lower-income participants. Males reported threshold effects in terms of perceived friendship competence and depressive symptoms. Male sport participants and lower-income adolescents reported a similar pattern for loneliness. Findings suggest that among a high achieving sample of urban adolescents, social and psychological benefits are linked to moderate but not intense involvement in OAs and sports. PMID:21752459

Randall, Edin T; Bohnert, Amy M

2011-07-12

74

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

PubMed Central

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.

Rafii, Forough; Seyedfatemi, Naima; Rezaei, Mahboubeh

2013-01-01

75

Structural parts involved in activation and inactivation of the sodium channel  

Microsoft Academic Search

Structure-function relationships of the sodium channel expressed inXenopus oocytes have been investigated by the combined use of site-directed mutagenesis and patch-clamp recording. This study provides evidence that the positive charges in segment S4 are involved in the voltage-sensing mechanism for activation of the channel and that the region between repeats III and IV is important for its inactivation.

Walter Stühmer; Franco Conti; Harukazu Suzuki; Xiaodong Wang; Masaharu Noda; Naoki Yahagi; Hideo Kubo; Shosaku Numa

1989-01-01

76

Molecular Mechanisms Involved in the Activation of Rhodopsin-Like Seven-Transmembrane Receptors  

Microsoft Academic Search

Seven-transmembrane receptors (7TMRs) comprise a large family of membrane-bound proteins that share a unifying signal transduction\\u000a mechanism (i.e., upon activation, these receptors signal through G proteins). These receptors are involved in a vast variety\\u000a of physiological functions, including neurotransmission, function of exocrine and endocrine glands, smell, taste, vision,\\u000a chemotaxis, embryogenesis, development, human immunodeficiency virus (HIV) infection, oncogenesis, cell growth, and

Peng Huang; Lee-Yuan Liu-Chen

77

Direct evidence for involvement of dopaminergic inhibition and cholinergic activation in yawning  

Microsoft Academic Search

A behavioral study was performed in an attempt to understand the neurological mechanism involved in yawning in rats. Intraperitoneal injections of low doses (0.25 mg\\/kg) of apomorphine, which preferentially activate presynaptic dopamine autoreceptors, elicited yawning. Whereas apomorphine, at a high dose of 2 mg\\/kg, produces stereotypy which has been thought to be mediated by stimulation of postsynaptic dopamine receptors. The

Katsushi Yamada; Tatsuo Furukawa

1980-01-01

78

Mechanisms involved in VPAC receptors activation and regulation: lessons from pharmacological and mutagenesis studies  

PubMed Central

Vasoactive intestinal peptide (VIP) plays diverse and important role in human physiology and physiopathology and their receptors constitute potential targets for the treatment of several diseases such as neurodegenerative disorder, asthma, diabetes, and inflammatory diseases. This article reviews the current knowledge regarding the two VIP receptors, VPAC1 and VPAC2, with respect to mechanisms involved in receptor activation, G protein coupling, signaling, regulation, and oligomerization.

Langer, Ingrid

2012-01-01

79

Lyssavirus Matrix Protein Induces Apoptosis by a TRAIL-Dependent Mechanism Involving Caspase8 Activation  

Microsoft Academic Search

Lyssaviruses, which are members of the Rhabdoviridae family, induce apoptosis, which plays an important role in the neuropathogenesis of rabies. However, the mechanisms by which these viruses mediate neuronal apoptosis have not been elucidated. Here we demonstrate that the early induction of apoptosis in a model of lyssavirus-infected neuroblastoma cells involves a TRAIL-dependent pathway requiring the activation of caspase-8 but

Raďd Kassis; Florence Larrous; Jerome Estaquier; H. Bourhy

2004-01-01

80

Ethnolinguistic Identity and Youth Activity Involvement in a Sample of Minority Canadian Francophone Youth  

Microsoft Academic Search

We examined the concept of “ethnolinguistic identity” in a national sample of 333 minority Canadian Francophone youth. Youth were categorized into one of four ethnolinguistic categories (integration, separation, assimilation, marginalization) based on commitment\\/affiliation and self-identification with Francophone and Anglophone cultures. Differences among categories were observed for activity-related identity performance, psychological engagement, and perceived impact of involvement. Youth in the separation

David Y. Bourgeois; Michael A. Busseri; Linda Rose-Krasnor

2009-01-01

81

Two transcribing activities are involved in expression of the Streptomyces galactose operon.  

PubMed Central

The Streptomyces galactose operon is transcribed from two independently regulated promoters: galP1, located at the 5' end of the operon and responsible for galactose-dependent transcription of the operon, and galP2, an internal constitutive promoter. We identified and partially separated two distinct transcribing activities involved in expression of this operon. Using RNA polymerase from Streptomyces lividans and Streptomyces coelicolor partially purified by chromatography on heparin-agarose and DNA-cellulose, we detected activities capable of initiating transcription in vitro specifically from either galP1 or galP2. Circumstantial evidence suggests that the activity for galP2 transcription is a holoenzyme species associated with the previously described sigma 28 protein (referred to here as sigma C). The galP1-transcribing activity is more difficult to evaluate. This activity may correspond to a holoenzyme species associated with sigma A (formerly sigma 35), although other possibilities are discussed. This would be the second reported example of a catabolite-controlled gene in Streptomyces species expressed from multiple promoters recognized by different holoenzyme forms. This may indicate that the involvement of RNA polymerase heterogeneity in gene expression in Streptomyces species is a more general strategy for regulation than the specialized gene expression seen in Escherichia coli. Images

Westpheling, J; Brawner, M

1989-01-01

82

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

83

Extracurricular activities in young applicants' résumés: What are the motives behind their involvement?  

PubMed

Applicants use résumés to demonstrate their knowledge, skills, abilities, and other personal characteristics (KSAOs) to recruiters, through education and job-related or non-job-related experiences. But research suggests that the situation for young applicants is especially competitive, since they increasingly enter the labour market with similar educational credentials and limited job-related experience. They may thus use non-job-related experiences, such as participation in extracurricular activities (ECAs) during their studies, to demonstrate KSAOs to recruiters, but also to add distinction and value to their credentials. ECAs may therefore become more important in the selection of young applicants. Yet few studies have undertaken a comprehensive and systematic analysis of the relationships students have with these activities. The purpose of this study was to investigate to what extent students' involvement in ECAs is due to internal (e.g., passion) or external (e.g., résumé-building) motives, and what factors influence these motives. Results from a study with 197 students suggest that students engage in ECAs mainly out of internal motives. But external motives are stronger for activities started closer to entering the labour market, for students active in associative or volunteering activities (as compared to sports or artistic activities), and for students holding leadership positions in their activities. Our results suggest that labour market pressure may be a key component of applicants' involvement in ECAs. Also, organizations and recruiters may want to consider that students tend not to engage in ECAs purely out of internal motives, but also to add value to their credentials and match employers' expectations. The authors thank Anna Ambrosetti for her help with the data collection. PMID:22823060

Roulin, Nicolas; Bangerter, Adrian

2012-07-24

84

Involvement of P2X4 receptors in hippocampal microglial activation after status epilepticus.  

PubMed

Within the central nervous system, functions of the ATP-gated receptor-channel P2X4 (P2X4R) are still poorly understood, yet P2X4R activation in neurons and microglia coincides with high or pathological neuronal activities. In this study, we investigated the potential involvement of P2X4R in microglial functions in a model of kainate (KA)-induced status epilepticus (SE). We found that SE was associated with an induction of P2X4R expression in the hippocampus, mostly localized in activated microglial cells. In P2X4R-deficient mice, behavioral responses during KA-induced SE were unaltered. However, 48h post SE specific features of microglial activation, such as cell recruitment and upregulation of voltage-dependent potassium channels were impaired in P2X4R-deficient mice, whereas the expression and function of other microglial purinergic receptors remained unaffected. Consistent with the role of P2X4R in activity-dependent degenerative processes, the CA1 area was partially protected from SE-induced neuronal death in P2X4R-deficient mice compared with wild-type animals. Our findings demonstrate that P2X4Rs are brought into play during neuronal hyperexcitability and that they control specific aspects of microglial activation. Our results also suggest that P2X4Rs contribute to excitotoxic damages by regulating microglial activation. PMID:23828736

Ulmann, Lauriane; Levavasseur, Françoise; Avignone, Elena; Peyroutou, Ronan; Hirbec, Hélčne; Audinat, Etienne; Rassendren, François

2013-07-04

85

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

2012-04-26

86

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

87

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

88

Secretion of a lysophospholipase D activity by adipocytes: involvement in lysophosphatidic acid synthesis  

PubMed Central

The aim of the present work was to depict the metabolic pathways involved in extra-cellular production of lysophosphatidic acid (LPA) by adipocytes. LPA was followed by quantifying the accumulation of LPA in the incubation medium (conditioned medium: CM) of 3T3F442A adipocytes, or human adipose tissue explants, using a radioenzymatic assay. Surprisingly, after separation from the cells, the amount of LPA present in CM could significantly be increased by further incubation at 37°C. This suggested the presence of a LPA-synthesizing activity (LPA-SA) in CM. LPA-SA appeared as a soluble activity which was inhibited by divalent ion chelators: EDTA and phenanthrolin. The effect of EDTA was preferentially reverted by CoCl2, as described for a lysophospholipase D- (lyso-PLD) activity previously identified in rat plasma. LPA concentration could also be increased by treatment with a bacterial PLD, demonstrating the presence of PLD-sensitive LPA-precursors (mainly lysophosphatidylcholine) in adipocyte CM. LPA-SA could be increased by addition of exogenous lysophosphatidylcholine, lysophosphatidylglycerol, or lyso-platelet activating factor, demonstrating that LPA-SA resulted from the action of a lyso-PLD. LPA-SA was not inhibited, but rather activated, by primary alcohol (ethanol and 1-butanol), suggesting that adipocyte lyso-PLD was not a classical PLD. Finally, LPA-SA was found to be weaker in CM of undifferentiated adipocyte (preadipocytes) as compared to CM of differentiated adipocytes. In conclusion, our results reveal the existence of a secreted lyso-PLD activity regulated during adipocyte-differentiation and involved in extra-cellular production of synthesis of LPA by adipocytes.

Gesta, Stephane; Simon, Marie-Francoise; Rey, Astrid; Sibrac, David; Girard, Alexia; Lafontan, Max; Valet, Philippe; Saulnier-Blache, Jean Sebastien

2002-01-01

89

Mutational Analysis of Cvab, an ABC Transporter Involved in the Secretion of Active Colicin V  

PubMed Central

CvaB is the central membrane transporter of the colicin V secretion system that belongs to an ATP-binding cassette superfamily. Previous data showed that the N-terminal and C-terminal domains of CvaB are essential for the function of CvaB. N-terminal domain of CvaB possesses Ca2+-dependent cysteine proteolytic activity, and two critical residues, Cys32 and His105, have been identified. In this study, we also identify Asp121 as being the third residue of the putative catalytic triad within the active site of the enzyme. The Asp121 mutants lose both their colicin V secretion activity and N-terminal proteolytic activity. The adjacent residue Pro122 also appears to play a critical role in the colicin V secretion. However, the reversal of the two residues D121P - P122D results in loss of activity. Based on molecular modeling and protein sequence alignment, several residues adjacent to the critical residues, Cys32 and His105, were also examined and characterized. Site-directed mutagenesis of Trp101, Asp102, Val108, Leu76, Gly77, and Gln26 indicate that the neighboring residues around the catalytic triad affect colicin V secretion. Several mutated CvaB proteins with defective secretion were also tested, including Asp121 and Pro122, and were found to be structurally stable. These results indicate that the residues surrounding the identified catalytic triad are functionally involved in the secretion of biologically active colicin V.

Tai, Phang C.

2012-01-01

90

Serotonergic involvement in methamphetamine-induced locomotor activity: a detailed pharmacological study.  

PubMed

The mechanism by which the psychostimulant methamphetamine (METH) increases locomotor activity may be attributable to indirect activation of serotonin (5-HT) and dopamine (DA) receptors. In the present study, the ability of the serotonin reuptake inhibitor fluvoxamine, 5-HT(1A), 5-HT(1B), 5-HT(2A) and 5-HT(2C) receptor antagonists WAY100635, GR127935, M100907 and SB242084, and the 5-HT(2C) receptor agonists WAY163909 and Ro 60-0175 or the 5-HT synthesis inhibitor para-chlorophenylalanine (pCPA) to alter METH-induced hyperactivity was analysed. Further, for comparative purposes, the involvement of the DA D(1) and D(2) receptor antagonists SCH23390 and haloperidol, D(2) partial agonists terguride, (-)3PPP and aripiprazole and finally clozapine were assessed. Doses of pCPA that attenuated 5-HT levels reduced METH activity. The 5-HT(1B) antagonist GR127935 had no effect on METH-induced locomotor activity but blocked that induced by MDMA. The 5-HT(1A) antagonist WAY100635 reduced activity but this did not reach significance. In contrast, M100907 (minimal effective dose; MED=0.125 mg/kg), WAY163909 (MED=3mg/kg), Ro 60-0175 (MED=3mg/kg), haloperidol (MED=0.1mg/kg), clozapine (MED=5mg/kg), aripiprazole (MED=1mg/kg), (-)3PPP (MED=3mg/kg), terguride (MED=0.2mg/kg) and SCH23390 (MED=0.001325 mg/kg) attenuated METH-induced locomotor activity. Administration of 20mg/kg fluvoxamine attenuated, while SB242084 (MED=0.25mg/kg) potentiated METH-induced activity. These results contribute significantly to the understanding of the mechanism of action of this psychostimulant and suggest for the first time, that METH-induced locomotor stimulation is modulated by 5-HT(2A) and 5-HT(2C) receptors, but demonstrate that 5-HT(1B) receptors are not directly involved. The involvement of the dopaminergic system was also demonstrated. PMID:21262272

Steed, Emily; Jones, Caitlin A; McCreary, Andrew C

2011-01-22

91

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

92

A novel antigen (H47 Ag) on human lymphocytes involved in T cell activation.  

PubMed

Surface molecules involved in human T cell activation were investigated using a newly developed monoclonal antibody (H47 mAb). H47 antigen (Ag) recognized by H47 mAb was expressed on approximately 10% of resting T cells (mostly CD4-CD8+), 30% of phorbol 12-myristate 13-acetate (PMA)-activated T cells (both CD4+CD8- and CD4-CD8+), and most NK, B cells, and monocytes in the peripheral blood mononuclear cells (PBMC). H47 mAb respectively immunoprecipitated a 100 or 120-kD molecular weight (MW) membrane protein of T cells and monocytes under nonreducing or reducing conditions, suggesting that H47 Ag consists of a single polypeptide that has intramolecular disulfide bonds. H47 mAb significantly enhanced PMA-induced proliferation of PBMC in a monocyte-independent fashion. H47 mAb, however, failed to enhance T cell proliferation induced by anti-CD3 mAb, anti-CD2 mAb, or phytohemagglutinin (PHA). H47 mAb also enhanced PMA-induced interleukin-2 receptor (IL-2R) expression and IL-2 synthesis, but did not induce a change in intracellular free calcium ([Ca2+]i) of T cells. These results suggest that H47 Ag is a new membrane molecule involved in PMA-induced T cell activation. PMID:8258145

Hirohashi, N; Nakao, M; Kubo, K; Yamada, A; Shichijo, S; Hara, A; Sagawa, K; Itoh, K

1993-12-01

93

Involvement of ras activation in toxic hair cell damage of the mammalian cochlea.  

PubMed

To identify possible intracellular mediators of hair cell (HC) death due to ototoxins, we treated basal-turn, neonatal, rat HCs in vitro with several intracellular signaling inhibitors, prior to and during gentamicin exposure. The general guanine nucleotide-binding protein (G-protein) inhibitor, GDP-betaS (1 mM), provided potent HC protection, suggesting involvement of G-proteins in the intracellular pathway linking gentamicin exposure to HC death. ADP-betaS had minimal effect, indicating that the protection is specific to guanosine diphosphate (GDP)-binding, rather than a general reaction to nucleotides. Azido-GTP(32) photolabeling and gel electrophoresis indicated activation of an approximately 21 kDa G-protein in HCs after exposure to gentamicin. Spectroscopic analysis of peptide fragments from this band matched its sequence with H-Ras. The Ras inhibitors B581 (50 microM) and FTI-277 (10 microM) provided potent protection against damage and reduced c-Jun activation in HC nuclei, suggesting that activation of Ras is functionally involved in damage to these cells due to gentamicin. PMID:14643769

Battaglia, A; Pak, K; Brors, D; Bodmer, D; Frangos, J A; Ryan, A F

2003-01-01

94

The involvement of 5-hydroxymethylcytosine in active DNA demethylation in mice.  

PubMed

Active DNA demethylation occurs after a sperm enters an egg. However, the mechanisms for the active DNA demethylation remain poorly understood. Ten-eleven translocation enzymes were recently shown to catalyze the conversion of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Thus, we decided to investigate the role of 5hmC in active demethylation. We analyzed the methylation and hydroxymethylation status in metaphase II oocytes as well as 1-cell stage and cleavage stage embryos. In zygotes, 5hmC was mainly detected in the paternal pronucleus and it increased from the pronuclear-2 (PN2) to PN5 stages, an indication that 5hmC was involved in paternal genomic DNA demethylation. Bisulfite-sequencing PCR and qGluMS-PCR (DNA glucosylation and digestion before quantitative PCR) results showed that a large reduction of methylcytosine and hydroxymethylcytosine in LINE1 (long interspersed nuclear element 1) occurred between the 4- and 8-cell stages, which indicates that demethylation potentially occurred after the 4-cell stage. We then microinjected mouse zygote with plasmids that were methylated in vitro by SssI methylase and analyzed for the hydroxymethylation status of the plasmids promoter region. We found that the rapid onset of expression of the unmethylated plasmids in mouse embryos happened in <12 h, but the expression of methylated plasmids was delayed until 50 h when most embryos were at the 8-cell stage. Quantitative GluMS-PCR results suggested that 5hmC was present in the plasmid's promoter region at the MspI site where the active demethylation occurred. Our results demonstrate that 5hmC is involved in active demethylation in mice. PMID:22262693

Zhang, Peng; Su, Li; Wang, Zhongwei; Zhang, Sheng; Guan, Jiyu; Chen, Yue; Yin, Yupeng; Gao, Fei; Tang, Bo; Li, Ziyi

2012-04-05

95

Ovulation involves the luteinizing hormone-dependent activation of gq/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

2013-07-08

96

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

2012-05-03

97

Signaling pathways involved in atrial natriuretic factor and dopamine regulation of renal Na+, K+ -ATPase activity.  

PubMed

Dopamine (DA) and atrial natriuretic factor (ANF) share a number of physiological effects. We hypothesized that ANF and the renal dopaminergic system could interact and enhance the natriuretic and diuretic effects of the peptide. We have previously reported that the ANF-stimulated DA uptake in renal tubular cells is mediated by the natriuretic peptide type-A receptor (NPR-A). Our aim was to investigate the signaling pathways that mediate ANF effects on renal 3H-DA uptake. Methylene blue (10 microM), an unspecific inhibitor of guanylate cyclase (GC), blunted ANF elicited increase of DA uptake. ODQ (10 microM) a specific inhibitor of soluble GC, did not modify DA uptake and did not reverse ANF-induced increase of DA uptake; then the participation of nitric oxide-dependent pathways must be discarded. The second messenger was the cGMP since the analogous 125 microM 8-Br-cGMP mimicked ANF effects. The specific inhibitor of the protein kinase G (PKG), KT 5823 (1 microM) blocked ANF effects indicating that PKG is involved. We examined if ANF effects on DA uptake were able to modify Na+, K+ -adenosine triphosphatase (Na+, K+ -ATPase) activity. The experiments were designed by means of inhibition of renal DA synthesis by carbidopa and neuronal DA uptake blocked by nomifensine. In these conditions renal Na+, K+ -ATPase activity was increased, in agreement with the decrease of DA availability. When in similar conditions, exogenous DA was added to the incubation medium, the activity of the enzyme tended to decrease, following to the restored availability of DA. The addition of ANF alone had similar effects to the addition of DA on the sodium pump, but when both were added together, the activity of Na(+), K(+)-ATPase was decreased. Moreover, the extraneuronal uptake blocker, hydrocortisone, inhibited the latter effect. In conclusion, ANF stimulates extraneuronal DA uptake in external cortex tissues by activation of NPR-A receptors coupled to GC and it signals through cGMP as second messenger and PKG. Dopamine and ANF may achieve their effects through a common pathway that involves reversible deactivation of renal tubular Na+, K+ -ATPase activity. This mechanism demonstrates a DA-ANF relationship involved in the modulation of both decreased sodium reabsorption and increased natriuresis. PMID:17005263

Correa, Alicia H; Choi, Marcelo R; Gironacci, Mariela; Valera, María S; Fernández, Belisario E

2006-09-26

98

Lyn is involved in CD24-induced ERK1/2 activation in colorectal cancer  

PubMed Central

Background and aim CD24 expression is associated with human colorectal cancer (CRC). Our previous data indicated that CD24 promoted the proliferation and invasion of colorectal cancer cells through the activation of ERK1/2. Since Src family kinases are frequently deregulated in CRC and closely related to the MAPK signaling pathway, we investigated the impact of Lyn, an important member of SFKs, on CD24-induced ERK1/2 activation in CRC. Methods and Results The interaction of CD24 and Lyn was identified by co-immunoprecipitation (Co-IP) and ectopic expression of CD24-induced Lyn activation. Inhibition of Lyn activation by phosphatase PP2 in SW480CD24cells abrogated CD24-induced invasion. The results of the Co-IP and immunofluorescence assay revealed that overexpression of CD24 enhanced the interaction of Lyn and ERK1/2 and induced the nuclear translocation of Lyn. However, inhibition of Lyn activity attenuated CD24-induced ERK1/2 activation, and depletion of CD24 disrupted Lyn-ERK1/2 interaction. Immunohistochemistry analysis for 202 cases of CRC showed that the expression of both CD24 and Lyn was positively correlated with tumor grade, stage, lymph node and distant metastasis. Patients with lower expression of CD24 or Lyn had a higher survival rate. The Cox multivariate analysis showed that CD24 expression, but not Lyn expression, was an independent prognostic factor of CRC. Conclusions Our results suggest that Lyn is involved in CD24-induced ERK1/2 activation in CRC. The expression of CD24 is associated with activation of Lyn and ERK1/2, which might be a novel mechanism related to CD24-mediated regulation of CRC development.

2012-01-01

99

Involvement of Microglia Activation in the Lead Induced Long-Term Potentiation Impairment  

PubMed Central

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.

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

2012-01-01

100

Eicosanoid activation of protein kinase C epsilon: involvement in growth cone repellent signaling.  

PubMed

Exposure of growing neurons to thrombin or semaphorin 3A stimulates a receptor-mediated signaling cascade that results in collapse of their growth cones. This collapse response necessitates eicosanoid production, as we have shown earlier. The present report investigates whether and which protein kinase C (PKC) isoforms may be activated by such eicosanoids. To examine these questions, we isolated growth cones from fetal rat brain and tested whether thrombin or the eicosanoid, 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), could activate endogenous growth cone PKC. We show that both thrombin and 12(S)-HETE stimulate the phosphorylation of the myristoylated alanine-rich protein kinase C substrate, an 87-kDa adhesion site protein. Furthermore, we show both with immunoprecipitated and with recombinant PKC that 12(S)-HETE activation is selective for the epsilon isoform and does not require accessory proteins. Last, we demonstrate that PKC activation is necessary for thrombin-induced growth cone collapse. These data indicate that eicosanoid-mediated repellent effects result from the direct and selective activation of PKCepsilon and suggest the involvement of myristoylated alanine-rich protein kinase C substrate phosphorylation in growth cone collapse. PMID:12665507

Mikule, Keith; Sunpaweravong, Somkiat; Gatlin, Jesse C; Pfenninger, Karl H

2003-03-28

101

BimL involvement in Bax activation during UV irradiation-induced apoptosis  

SciTech Connect

Bax, a proapoptotic member of the Bcl-2 family, localizes largely in the cytoplasm but translocates to mitochondria and undergoes oligomerization to induce the release of apoptogenic factors in response to apoptotic stimuli. However, the molecular mechanism of Bax activation is not fully understood. We show here the role of BimL in Bax activation during UV irradiation-induced apoptosis. In this study, GFP-BimL plasmid was constructed. The dynamic interaction between BimL and Bax during UV irradiation-induced apoptosis was observed using fluorescence resonance energy transfer (FRET) technique. Our experimental results showed that BimL translocation to mitochondria occurred before Bax translocation, and that BimL activated Bax indirectly. Moreover, inhibition of c-Jun N-terminal protein kinase (JNK) activation blocked BimL translocation, delayed and attenuated Bax translocation and subsequent apoptosis. These results demonstrate that BimL is involved in UV irradiation-induced apoptosis by indirectly activating Bax.

Chen, Miaojuan [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China); Xing, Da [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China)]. E-mail: xingda@scnu.edu.cn; Chen, Tongsheng [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China); Zhang, Lan [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, South China Normal University, Guangzhou 510631 (China)

2007-06-29

102

Fibrinolytic activation promoted by the cyclopentapeptide malformin: involvement of cytoskeletal reorganization.  

PubMed

Malformin A?, a cyclopentapeptide of fungal origin, enhances cellular fibrinolytic activity depending on the existence of a cofactor in blood plasma. However, the nature of this cofactor remains unknown. Here, we report that vitronectin acts as a plasma cofactor of malformin A?. We purified the cofactor from bovine plasma by activity-based fractionation, and confirmed that vitronectin in conjunction with plasminogen supports the activity of malformin A? to promote the fibrinolytic activity of U937 cells. Malformin A? action was abolished by Arg-Gly-Asp peptide (a competitor of vitronectin-integrin binding), wortmannin (an inhibitor of signaling kinases), and cytochalasin B (an inhibitor of actin polymerization). Changes in actin organization and a decrease in filopodia were observed in cells treated with malformin A? and plasma. A focal localization of plasminogen on the cell surface was augmented by malformin A?, whereas the amount of cell-surface-bound plasminogen was minimally altered by the treatment. Our results suggest the involvement of cytoskeletal reorganization via vitronectin signaling in the cellular fibrinolytic activity-enhancing action of malformin A?. PMID:21881228

Koizumi, Yukio; Fukudome, Hirofumi; Hasumi, Keiji

2011-01-01

103

Aesthetic activities and aesthetic attitudes: Influences of education, background and personality on interest and involvement in the arts  

Microsoft Academic Search

There have been few studies of why some people are frequently involved in aesthetic activities such as going to the theatre, reading or playing musical instruments, whereas others are less involved. This study assesses the broad roles of education, personality and demographic factors such as social class, age and sex. More aesthetic activity was associated with music and art education,

I. C. McManus; A. Furnham

2006-01-01

104

Active cytosine demethylation triggered by a nuclear receptor involves DNA strand breaks  

PubMed Central

Cytosine methylation at CpG dinucleotides contributes to the epigenetic maintenance of gene silencing. Dynamic reprogramming of DNA methylation patterns is believed to play a key role during development and differentiation in vertebrates. The mechanisms of DNA demethylation remain unclear and controversial. Here, we present a detailed characterization of the demethylation of an endogenous gene in cultured cells. This demethylation is triggered in a regulatory region by a transcriptional activator, the glucocorticoid receptor. We show that DNA demethylation is an active process, occurring independently of DNA replication, and in a distributive manner without concerted demethylation of cytosines on both strands. We demonstrate that the DNA backbone is cleaved 3? to the methyl cytidine during demethylation, and we suggest that a DNA repair pathway may therefore be involved in this demethylation.

Kress, Clemence; Thomassin, Helene; Grange, Thierry

2006-01-01

105

International carbon dioxide-related activities: the international organizations involved and US bilateral arrangements  

SciTech Connect

The issue of increasing carbon dioxide in the atmosphere, its measurement and possible impact, is one of global dimensions. Several organizations with international membership are actively involved in efforts to resolve the unanswered questions surrounding this issue. This paper describes broadly these international organizations and the type of CO/sub 2/-related activities they conduct and outlines the CO/sub 2/ research work conducted through US biliateral arrangements. The major international organizations that engage in CO/sub 2/-related research are the World Meteorological Organization (WMO), the United Nations Environment Programme (UNEP), the International Council of Scientific Unions (ICSU), the Scientific Committee on Problems of the Environment (SCOPE), the European Community, the International Energy Agency (IEA), the International Institute for Applied Systems Analysis (IIASA), and the International Atomic Energy Agency (IAEA).

Dougher, R.

1983-07-01

106

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

107

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

2012-01-30

108

Neuronal activity in macaque SEF and ACC during performance of tasks involving conflict.  

PubMed

It has been suggested on the basis of previous studies involving functional MRI (fMRI) and single-neuron recording that neurons of the supplementary eye field (SEF) and anterior cingulate cortex (ACC) monitor conflict. To test this idea, we carried out microelectrode recording in monkeys performing a color-conditional eye movement task in which red and green cues instructed leftward and rightward saccades, respectively. In a variant inducing conflict by spatial incompatibility, the cue was presented either at the location of the target (no conflict) or opposite the location of the target (conflict). In a variant inducing conflict by reversal, the foveal cue either remained one color (no conflict) or reversed color after 100 ms (conflict), with the monkey required to follow the instruction conveyed by the second color. In both tasks, conflict was evident in behavioral measures (reduced percent correct and slowed reaction time) and in physiological measures (reduced strength of directional activity among direction-selective neurons). In the SEF, there was a tendency for neurons to fire more strongly on trials involving conflict, but this effect took the form of modulation of task-related activity among direction-selective neurons, not of a pure conflict-monitoring signal. In the ACC, there was no conflict-related enhancement. These results are incompatible with the idea that the SEF and ACC contain populations of neurons specialized for monitoring conflict. PMID:15295008

Nakamura, Kae; Roesch, Matthew R; Olson, Carl R

2004-08-04

109

A national comparison of health information management|| students' career expectations and anticipated involvement in professional|| activities.  

PubMed

The aim of this paper is to present the results of a||| survey of Australian health information management students relating to their||| career aspirations and expectations and anticipated involvement in professional||| activities following graduation. To explain reasons for the differences in||| results between states and student years, interviews were conducted with||| academic staff and other health information management educators. Three hundred||| and sixty three students completed the questionnaire in 1996, which represented||| a response rate of 86%. It was found that the majority of students thought they||| had made the correct career choice and were confident they would find full-time||| employment within six months of graduation. A high percentage of students also||| indicated that they would undertake continuing education after graduation.||| There was less support for involvement in the activities of their professional||| association, particularly at a national level. Students in New South Wales and||| Queensland indicated that they would be significantly less likely to work in||| the field of health information management for the rest of their careers. They||| also reported they would be significantly less likely to conduct research in an||| area related to health information management. Victorian students were||| significantly more likely to present a paper at a conference than students from||| Queensland, New South Wales or Western Australia. Western Australian students||| were significantly more likely to report that they would undertake postgraduate||| studies compared to students from the other three states. PMID:11117112

Westbrook; Callen; Alechna

2000-01-01

110

A national comparison of health information management students' career expectations and anticipated involvement in professional activities.  

PubMed

The aim of this paper is to present the results of a survey of Australian health information management students relating to their career aspirations and expectations and anticipated involvement in professional activities following graduation. To explain reasons for the differences in results between states and student years, interviews were conducted with academic staff and other health information management educators. Three hundred and sixty three students completed the questionnaire in 1996, which represented a response rate of 86%. It was found that the majority of students thought they had made the correct career choice and were confident they would find full-time employment within six months of graduation. A high percentage of students also indicated that they would undertake continuing education after graduation. There was less support for involvement in the activities of their professional association, particularly at a national level. Students in New South Wales and Queensland indicated that they would be significantly less likely to work in the field of health information management for the rest of their careers. They also reported they would be significantly less likely to conduct research in an area related to health information management. Victorian students were significantly more likely to present a paper at a conference than students from Queensland, New South Wales or Western Australia. Western Australian students were significantly more likely to report that they would undertake postgraduate studies compared to students from the other three states. PMID:11142997

Westbrook, J; Callen, J; Alechna, N

2000-01-01

111

Caveolin-1 is involved in reactive oxygen species-induced SHP-2 activation in astrocytes.  

PubMed

Recent evidence supports a neuroprotective role of Src homology 2-containing protein tyrosine phosphatase 2 (SHP-2) against ischemic brain injury. However, the molecular mechanisms of SHP-2 activation and those governing how SHP-2 exerts its function under oxidative stress conditions are not well understood. Recently we have reported that reactive oxygen species (ROS)-mediated oxidative stress promotes the phosphorylation of endogenous SHP-2 through lipid rafts, and that this phosphorylation strongly occurs in astrocytes, but not in microglia. To investigate the molecules involved in events leading to phosphorylation of SHP-2, raft proteins were analyzed using astrocytes and microglia. Interestingly, caveolin-1 and -2 were detected only in astrocytes but not in microglia, whereas flotillin-1 was expressed in both cell types. To examine whether the H2O2-dependent phosphorylation of SHP-2 is mediated by caveolin-1, we used specific small interfering RNA (siRNA) to downregulate caveolin- 1 expression. In the presence of caveolin-1 siRNA, the level of SHP-2 phosphorylation induced by H2O2 was significantly decreased, compared with in the presence of control siRNA. Overexpression of caveolin- 1 effectively increased H2O2-induced SHP-2 phosphorylation in microglia. Lastly, H2O2 induced extracellular signal-regulated kinase (ERK) activation in astrocytes through caveolin-1. Our results suggest that caveolin-1 is involved in astrocyte-specific intracellular responses linked to the SHP-2-mediated signaling cascade following ROS-induced oxidative stress. PMID:21918362

Yun, Ji Hee; Park, Soo Jung; Jo, Ara; Kang, Jihee Lee; Jou, Ilo; Park, Jung Soo; Choi, Youn Hee

2011-12-31

112

Effects of negative air ions on activity of neural substrates involved in autonomic regulation in rats  

NASA Astrophysics Data System (ADS)

The neural mechanism by which negative air ions (NAI) mediate the regulation of autonomic nervous system activity is still unknown. We examined the effects of NAI on physiological responses, such as blood pressure (BP), heart rate (HR), and heart rate variability (HRV) as well as neuronal activity, in the paraventricular nucleus of the hypothalamus (PVN), locus coeruleus (LC), nucleus ambiguus (NA), and nucleus of the solitary tract (NTS) with c-Fos immunohistochemistry in anesthetized, spontaneously breathing rats. In addition, we performed cervical vagotomy to reveal the afferent pathway involved in mediating the effects of NAI on autonomic regulation. NAI significantly decreased BP and HR, and increased HF power of the HRV spectrum. Significant decreases in c-Fos positive nuclei in the PVN and LC, and enhancement of c-Fos expression in the NA and NTS were induced by NAI. After vagotomy, these physiological and neuronal responses to NAI were not observed. These findings suggest that NAI can modulate autonomic regulation through inhibition of neuronal activity in PVN and LC as well as activation of NA neurons, and that these effects of NAI might be mediated via the vagus nerves.

Suzuki, Satoko; Yanagita, Shinya; Amemiya, Seiichiro; Kato, Yumi; Kubota, Natsuko; Ryushi, Tomoo; Kita, Ichiro

2008-07-01

113

Mechanisms involved in modulation of trigeminal primary afferent activity in rats with peripheral mononeuropathy.  

PubMed

In order to clarify the mechanisms underlying the changes in primary afferent neurons in trigeminal neuropathic pain, a chronic constriction nerve injury model of the infraorbital nerve (ION-CCI) was developed in rats. Mechanical allodynia was observed at 3 days after ION-CCI and lasted more than 14 days. Single-unit activities were recorded from the ION of anesthetized rats. C-, Abeta- and Adelta-units were identified on the basis of their conduction velocity. Adelta-units were frequently encountered at a later period after ION-CCI. The highest Adelta-spontaneous activity was recorded at 3 days after ION-CCI and progressively decreased after that, but spontaneous activity was still higher at 14 days after ION-CCI than that of naďve rats. Mechanical-evoked responses of Adelta-units were also highest at 3 days after ION-CCI and then gradually decreased. In consideration of these data, patch-clamp recordings were performed on medium to large size neurons of the dissociated trigeminal ganglion (TRG). Patch-clamp recordings revealed that the IK (sustained) and IA (transient) in rats with ION-CCI were significantly smaller than those of naďve rats, and correlated with an increase in duration of repolarization phase and a decrease in duration of depolarization phase, respectively. The hyperpolarization-activated current (Ih) was significantly larger in TRG neurons of rats with ION-CCI as compared with those of naďve rats. The present results suggest that Ih, IK and IA in Adelta-afferent neurons in TRG are significantly involved in the changes in afferent spontaneous activity and mechanically evoked activity that accompany mechanical allodynia produced by trigeminal nerve injury. PMID:17040479

Kitagawa, Junichi; Takeda, Mamoru; Suzuki, Ikuko; Kadoi, Jun; Tsuboi, Yoshiyuki; Honda, Kuniya; Matsumoto, Shigeji; Nakagawa, Hiroshi; Tanabe, Aya; Iwata, Koichi

2006-10-16

114

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

115

Differential involvement of projection neurons during emergence of spontaneous activity in the developing avian hindbrain.  

PubMed

To better characterize the emergence of spontaneous neuronal activity in the developing hindbrain, spontaneous activity was recorded optically from defined projection neuron populations in isolated preparations of the brain stem of the chicken embryo. Ipsilaterally projecting reticulospinal (RS) neurons and several groups of vestibuloocular (VO) neurons were labeled retrogradely with Calcium Green-1 dextran amine and spontaneous calcium transients were recorded using a charge-coupled-device camera mounted on a fluorescence microscope. Simultaneous extracellular recordings were made from one of the trigeminal motor nerves (nV) to register the occurrence of spontaneous synchronous bursts of activity. Two types of spontaneous activity were observed: synchronous events (SEs), which occurred in register with spontaneous bursts in nV once every few minutes and were tetrodotoxin (TTX) dependent, and asynchronous events (AEs), which occurred in the intervals between SEs and were TTX resistant. AEs occurred developmentally before SEs and were in general smaller and more variable in amplitude than SEs. SEs appeared at the same stage as nV bursts early on embryonic day 4, first in RS neurons and then in VO neurons. All RS neurons participated equally in SEs from the outset, whereas different subpopulations of VO neurons participated differentially, both in terms of the proportion of neurons that exhibited SEs, the fidelity with which the SEs in individual neurons followed the nV bursts, and the developmental stage at which SEs appeared and matured. The results show that spontaneous activity is expressed heterogeneously among hindbrain projection neuron populations, suggesting its differential involvement in the formation of different functional neuronal circuits. PMID:19036869

Mochida, Hiraku; Fortin, Gilles; Champagnat, Jean; Glover, Joel C

2008-11-26

116

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

117

Carbohydrate-active enzymes involved in the secondary cell wall biogenesis in hybrid aspen.  

PubMed

Wood formation is a fundamental biological process with significant economic interest. While lignin biosynthesis is currently relatively well understood, the pathways leading to the synthesis of the key structural carbohydrates in wood fibers remain obscure. We have used a functional genomics approach to identify enzymes involved in carbohydrate biosynthesis and remodeling during xylem development in the hybrid aspen Populus tremula x tremuloides. Microarrays containing cDNA clones from different tissue-specific libraries were hybridized with probes obtained from narrow tissue sections prepared by cryosectioning of the developing xylem. Bioinformatic analyses using the sensitive tools developed for carbohydrate-active enzymes allowed the identification of 25 xylem-specific glycosyltransferases belonging to the Carbohydrate-Active EnZYme families GT2, GT8, GT14, GT31, GT43, GT47, and GT61 and nine glycosidases (or transglycosidases) belonging to the Carbohydrate-Active EnZYme families GH9, GH10, GH16, GH17, GH19, GH28, GH35, and GH51. While no genes encoding either polysaccharide lyases or carbohydrate esterases were found among the secondary wall-specific genes, one putative O-acetyltransferase was identified. These wood-specific enzyme genes constitute a valuable resource for future development of engineered fibers with improved performance in different applications. PMID:15734915

Aspeborg, Henrik; Schrader, Jarmo; Coutinho, Pedro M; Stam, Mark; Kallas, Asa; Djerbi, Soraya; Nilsson, Peter; Denman, Stuart; Amini, Bahram; Sterky, Fredrik; Master, Emma; Sandberg, Göran; Mellerowicz, Ewa; Sundberg, Björn; Henrissat, Bernard; Teeri, Tuula T

2005-02-25

118

Recovery of Respiratory Activity after C2 hemisection (C2HS): Involvement of Adenosinergic Mechanisms  

PubMed Central

Consequences of spinal cord injury (SCI) depend on the level and extent of injury. Cervical SCI often results in a compromised respiratory system. Primary treatment of SCI patients with respiratory insufficiency continues to be with mechanical ventilatory support. In an animal model of SCI, an upper cervical spinal cord hemisection paralyzes the hemidiaphragm ipsilateral to the side of injury. However, a latent respiratory motor pathway can be activated to restore respiratory function after injury. In this review, restoration of respiratory activity following systemic administration of theophylline, a respiratory stimulant will be discussed. Pharmacologically, theophylline is a non specific adenosine receptor antagonist, a phosphodiesterase inhibitor and a bronchodilator. It has been used in the treatment of asthma and other respiratory-related diseases such as chronic obstructive pulmonary disease (COPD) and in treatment of apnea in premature infants. However, the clinical use of theophylline to improve respiration in SCI patients with respiratory deficits is a more recent approach. This review will focus on the use theophylline to restore respiratory activity in an animal model of SCI. In this model, a C2 hemisection (C2HS) interrupts the major descending respiratory pathways and paralyzes the ipsilateral hemidiaphragm. The review also highlights involvement of central and peripheral adenosine receptors in functional restitution. Biochemical binding assays that highlight changes in adenosine receptors after chronic theophylline administration are discussed as they pertain to understanding adenosine receptor-mediation in functional recovery. Finally, the clinical application of theophylline in SCI patients with respiratory deficits in particular is discussed.

Nantwi, Kwaku D.

2009-01-01

119

TRAIL induces necroptosis involving RIPK1/RIPK3-dependent PARP-1 activation.  

PubMed

Although TRAIL (tumor necrosis factor (TNF)-related apoptosis inducing ligand) is a well-known apoptosis inducer, we have previously demonstrated that acidic extracellular pH (pHe) switches TRAIL-induced apoptosis to regulated necrosis (or necroptosis) in human HT29 colon and HepG2 liver cancer cells. Here, we investigated the role of RIPK1 (receptor interacting protein kinase 1), RIPK3 and PARP-1 (poly (ADP-ribose) polymerase-1) in TRAIL-induced necroptosis in vitro and in concanavalin A (Con A)-induced murine hepatitis. Pretreatment of HT29 or HepG2 with pharmacological inhibitors of RIPK1 or PARP-1 (Nec-1 or PJ-34, respectively), or transient transfection with siRNAs against RIPK1 or RIPK3, inhibited both TRAIL-induced necroptosis and PARP-1-dependent intracellular ATP depletion demonstrating that RIPK1 and RIPK3 were involved upstream of PARP-1 activation and ATP depletion. In the mouse model of Con A-induced hepatitis, where death of mouse hepatocytes is dependent on TRAIL and NKT (Natural Killer T) cells, PARP-1 activity was positively correlated with liver injury and hepatitis was prevented both by Nec-1 or PJ-34. These data provide new insights into TRAIL-induced necroptosis with PARP-1 being active effector downstream of RIPK1/RIPK3 initiators and suggest that pharmacological inhibitors of RIPKs and PARP-1 could be new treatment options for immune-mediated hepatitis. PMID:22814620

Jouan-Lanhouet, S; Arshad, M I; Piquet-Pellorce, C; Martin-Chouly, C; Le Moigne-Muller, G; Van Herreweghe, F; Takahashi, N; Sergent, O; Lagadic-Gossmann, D; Vandenabeele, P; Samson, M; Dimanche-Boitrel, M-T

2012-07-20

120

1-Methyl-4-phenylpyridinium induces synaptic dysfunction through a pathway involving caspase and PKC? enzymatic activities  

PubMed Central

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration has been used, in various mammalian species, as an experimental model of Parkinson's disease. The pathogenesis for such pharmacologically induced Parkinson's disease involves 1-methyl-4-phenylpyridinium (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. This metabolite produces rapid degeneration of nigrostriatal dopaminergic neurons, which causes the parkinsonian syndrome. In this work, we show that injection of MPP+ into the presynaptic terminal of the squid giant synapse blocks synaptic transmission without affecting the presynaptic action potential or the presynaptic calcium currents. These effects of MPP+ were mimicked by the injection of an active form of caspase-3 and prevented by inhibitors of caspase-3 and protein kinase C ?. Ultrastructurally, MPP+-injected synapses showed a dramatic reduction in the number of neurotransmitter vesicles at the presynaptic active zone, as compared with control synapses. Otherwise, normal docking and clathrin-coated vesicles were observed, albeit at much reduced numbers. These results indicate that MPP+ acutely reduces presynaptic vesicular availability, not release, and that MPP+-induced pathogenesis results from presynaptic dysfunction that leads, secondarily, to dying-back neuropathy in affected neurons.

Serulle, Yafell; Morfini, Gerardo; Pigino, Gustavo; Moreira, Jorge E.; Sugimori, Mutsuyuki; Brady, Scott T.; Llinas, Rodolfo R.

2007-01-01

121

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

122

Occupational Styrene Exposure Induces Stress-Responsive Genes Involved in Cytoprotective and Cytotoxic Activities  

PubMed Central

Objective The aim of this study was to evaluate the expression of a panel of genes involved in toxicology in response to styrene exposure at levels below the occupational standard setting. Methods Workers in a fiber glass boat industry were evaluated for a panel of stress- and toxicity-related genes and associated with biochemical parameters related to hepatic injury. Urinary styrene metabolites (MA+PGA) of subjects and environmental sampling data collected for air at workplace were used to estimate styrene exposure. Results Expression array analysis revealed massive upregulation of genes encoding stress-responsive proteins (HSPA1L, EGR1, IL-6, IL-1?, TNSF10 and TNF?) in the styrene-exposed group; the levels of cytokines released were further confirmed in serum. The exposed workers were then stratified by styrene exposure levels. EGR1 gene upregulation paralleled the expression and transcriptional protein levels of IL-6, TNSF10 and TNF? in styrene exposed workers, even at low level. The activation of the EGR1 pathway observed at low-styrene exposure was associated with a slight increase of hepatic markers found in highly exposed subjects, even though they were within normal range. The ALT and AST levels were not affected by alcohol consumption, and positively correlated with urinary styrene metabolites as evaluated by multiple regression analysis. Conclusion The pro-inflammatory cytokines IL-6 and TNF? are the primary mediators of processes involved in the hepatic injury response and regeneration. Here, we show that styrene induced stress responsive genes involved in cytoprotection and cytotoxicity at low-exposure, that proceed to a mild subclinical hepatic toxicity at high-styrene exposure.

Strafella, Elisabetta; Bracci, Massimo; Staffolani, Sara; Manzella, Nicola; Giantomasi, Daniele; Valentino, Matteo; Amati, Monica; Tomasetti, Marco; Santarelli, Lory

2013-01-01

123

Tumor necrosis factor restricts hematopoietic stem cell activity in mice: involvement of two distinct receptors.  

PubMed

Whereas maintenance of hematopoietic stem cells (HSCs) is a requisite for life, uncontrolled expansion of HSCs might enhance the propensity for leukemic transformation. Accordingly, HSC numbers are tightly regulated. The identification of physical cellular HSC niches has underscored the importance of extrinsic regulators of HSC homeostasis. However, whereas extrinsic positive regulators of HSCs have been identified, opposing extrinsic repressors of HSC expansion in vivo have yet to be described. Like many other acute and chronic inflammatory diseases, bone marrow (BM) failure syndromes are associated with tumor necrosis factor-? (TNF) overexpression. However, the in vivo relevance of TNF in the regulation of HSCs has remained unclear. Of considerable relevance for normal hematopoiesis and in particular BM failure syndromes, we herein demonstrate that TNF is a cell-extrinsic and potent endogenous suppressor of normal HSC activity in vivo in mice. These effects of TNF involve two distinct TNF receptors. PMID:21768269

Pronk, Cornelis J H; Veiby, Ole Petter; Bryder, David; Jacobsen, Sten Eirik W

2011-07-18

124

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

PubMed Central

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.

Rodrigo, Maria J.; Alquezar, Berta; Al-Babili, Salim

2013-01-01

125

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

2013-09-04

126

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

2009-04-14

127

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

2013-08-22

128

Asthmatic airway smooth muscle CXCL10 production: mitogen-activated protein kinase JNK involvement  

PubMed Central

CXCL10 (IP10) is involved in mast cell migration to airway smooth muscle (ASM) bundles in asthma. We aimed to investigate the role of cytokine-induced MAPK activation in CXCL10 production by ASM cells from people with and without asthma. Confluent growth-arrested ASM cells were treated with inhibitors of the MAPKs ERK, p38, and JNK and transcription factor NF-?B, or vehicle, and stimulated with IL-1?, TNF-?, or IFN-?, alone or combined (cytomix). CXCL10 mRNA and protein, JNK, NF-?B p65 phosphorylation, and I?-B? protein degradation were assessed using real-time PCR, ELISA, and immunoblotting, respectively. Cytomix, IL-1?, and TNF-? induced CXCL10 mRNA expression more rapidly in asthmatic than nonasthmatic ASM cells. IL-1? and/or TNF-? combined with IFN-? synergistically increased asthmatic ASM cell CXCL10 release. Inhibitor effects were similar in asthmatic and nonasthmatic cells, but cytomix-induced release was least affected, with only JNK and NF-?B inhibitors halving it. Notably, JNK phosphorylation was markedly less in asthmatic compared with nonasthmatic cells. However, in both, the JNK inhibitor SP600125 reduced JNK phosphorylation and CXCL10 mRNA levels but did not affect CXCL10 mRNA stability or I?-B? degradation. Together, the JNK and NF-?B inhibitors completely inhibited their CXCL10 release. We concluded that, in asthmatic compared with nonasthmatic ASM cells, JNK activation was reduced and CXCL10 gene expression was more rapid following cytomix stimulation. However, in both, JNK activation did not regulate early events leading to NF-?B activation. Thus JNK and NF-?B provide independent therapeutic targets for limiting CXCL10 production and mast cell migration to the ASM in asthma.

Alrashdan, Yazan A.; Alkhouri, Hatem; Chen, Emily; Lalor, Daniel J.; Poniris, Maree; Henness, Sheridan; Brightling, Christopher E.; Burgess, Janette K.; Armour, Carol L.; Ammit, Alaina J.

2012-01-01

129

Differential involvement of mitochondrial dysfunction, cytochrome P450 activity, and active transport in the toxicity of structurally related NSAIDs.  

PubMed

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of pain and inflammation. However, this group of drugs is associated with serious adverse drug reactions. Previously, we studied the mechanisms underlying toxicity of the NSAID diclofenac using Saccharomycescerevisiae as model system. We identified the involvement of several mitochondrial proteins, a transporter and cytochrome P450 activity in diclofenac toxicity. In this study, we investigated if these processes are also involved in the toxicity of other NSAIDs. We divided the NSAIDs into three classes based on their toxicity mechanisms. Class I consists of diclofenac, indomethacin and ketoprofen. Mitochondrial respiration and reactive oxygen species (ROS) play a major role in the toxicity of this class. Metabolism by cytochrome P450s further increases their toxicity, while ABC-transporters decrease the toxicity. Mitochondria and oxidative metabolism also contribute to toxicity of class II drugs ibuprofen and naproxen, but another cellular target dominates their toxicity. Interestingly, ibuprofen was the only NSAID that was unable to induce upregulation of the multidrug resistance response. The class III NSAIDs sulindac, ketorolac and zomepirac were relatively non-toxic in yeast. In conclusion, we demonstrate the use of yeast to investigate the mechanisms underlying the toxicity of structurally related drugs. PMID:22138569

van Leeuwen, Jolanda S; Unlü, Betül; Vermeulen, Nico P E; Vos, J Chris

2011-11-26

130

Distal hinge of plasminogen activator inhibitor-1 involves its latency transition and specificities toward serine proteases  

PubMed Central

Background The plasminogen activator inhibitor-1 (PAI-1) spontaneously converts from an inhibitory into a latent form. Specificity of PAI-1 is mainly determined by its reactive site (Arg346-Met347), which interacts with serine residue of tissue-type plasminogen activator (tPA) with concomitant formation of SDS-stable complex. Other sites may also play roles in determining the specificity of PAI-1 toward serine proteases. Results To understand more about the role of distal hinge for PAI-1 specificities towards serine proteases and for its conformational transition, wild type PAI-1 and its mutants were expressed in baculovirus system. WtPAI-1 was found to be about 12 fold more active than the fibrosarcoma PAI-1. Single site mutants within the Asp355-Arg356-Pro357 segment of PAI-1 yield guanidine activatable inhibitors (a) that can still form SDS stable complexes with tPA and urokinase plasminogen activator (uPA), and (b) that have inhibition rate constants towards plasminogen activators which resemble those of the fibrosarcoma inhibitor. More importantly, latency conversion rate of these mutants was found to be ~3–4 fold faster than that of wtPAI-1. We also tested if Glu351 is important for serine protease specificity. The functional stability of wtPAI-1, Glu351Ala, Glu351Arg was about 18 ± 5, 90 ± 8 and 14 ± 3 minutes, respectively, which correlated well with both their corresponding specific activities (84 ± 15 U/ug, 112 ± 18 U/ug and 68 ± 9 U/ug, respectively) and amount of SDS-stable complex formed with tPA after denatured by Guanidine-HCl and dialyzed against 50 mM sodium acetate at 4°C. The second-order rate constants of inhibition for uPA, plasmin and thrombin by Glu351Ala and Glu351Arg were increased about 2–10 folds compared to wtPAI-1, but there was no change for tPA. Conclusion The Asp355-Pro357 segment and Glu351 in distal hinge are involved in maintaining the inhibitory conformation of PAI-1. Glu351 is a specificity determinant of PAI-1 toward uPA, plasmin and thrombin, but not for tPA.

Wang, Qingcai; Shaltiel, Shmuel

2003-01-01

131

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

132

Trichoderma mitogen-activated protein kinase signaling is involved in induction of plant systemic resistance.  

PubMed

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. PMID:16204544

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

2005-10-01

133

Involvement of BimL activation in apoptosis induced by lysosomal photodamage  

NASA Astrophysics Data System (ADS)

Lysosomal photosensitizers have been used in photodynamic therapy (PDT). Combination of such photosensitizers and light causes lysosomal photodamage, inducing cell death. The lysosomal disruption can lead to apoptosis but its signaling pathways remain to be elucidated. In this study, we selected N-aspartyl chlorin e6 (NPe6), an effective photosensitizer which preferentially accumulates in lysosomes, to study the mechanism of apoptosis caused by lysosomal photodamage. Apoptosis in living human lung adenocarcinoma cells treated by NPe6-PDT was studied using real-time single-cell analysis. Confocal imaging of cells transfected with BimL-GFP demonstrated that BimL translocated to mitochondria after NPe6-PDT treatment for about 150 min, and then sequestered into clusters associated with the mitochondira within 30 min. The activation of BimL proved to be an important event in the apoptotic machinery, as demonstrated by the significant protection of cell death in samples suppressed the expression level of endogenous BimL. This study demonstrates that BimL activation was involved in the cell death induced by PDT with lysosomal photosensitizer.

Liu, Lei; Wang, Xianwang; Li, Hui

2008-12-01

134

Plasminogen activator inhibitor-1 is involved in streptozotocin-induced bone loss in female mice.  

PubMed

In diabetic patients, the risk of fracture is high because of impaired bone formation. However, the details of the mechanisms in the development of diabetic osteoporosis remain unclear. In the current study, we investigated the role of plasminogen activator inhibitor (PAI)-1 in the pathogenesis of type 1 diabetic osteoporosis by using PAI-1-deficient mice. Quantitative computed tomography analysis showed that PAI-1 deficiency protected against streptozotocin-induced bone loss in female mice but not in male mice. PAI-1 deficiency blunted the changes in the levels of Runx2, osterix, and alkaline phosphatase in tibia as well as serum osteocalcin levels suppressed by the diabetic state in female mice only. Furthermore, the osteoclast levels in tibia, suppressed in diabetes, were also blunted by PAI-1 deficiency in female mice. Streptozotocin markedly elevated the levels of PAI-1 mRNA in liver in female mice only. In vitro study demonstrated that treatment with active PAI-1 suppressed the levels of osteogenic genes and mineralization in primary osteoblasts from female mouse calvaria. In conclusion, the current study indicates that PAI-1 is involved in the pathogenesis of type 1 diabetic osteoporosis in females. The expression of PAI-1 in the liver and the sensitivity of bone cells to PAI-1 may be an underlying mechanism. PMID:23715621

Tamura, Yukinori; Kawao, Naoyuki; Okada, Kiyotaka; Yano, Masato; Okumoto, Katsumi; Matsuo, Osamu; Kaji, Hiroshi

2013-05-28

135

Enzymes involved in the biosynthesis of leukotriene B 4 and prostaglandin E 2 are active in sebaceous glands  

Microsoft Academic Search

The expression of enzymes involved in leukotriene and prostaglandin signalling pathways, of interleukins 6 and 8 and of peroxisome proliferator-activated receptors in sebaceous glands of acne-involved facial skin was compared with those of non-involved skin of acne patients and of healthy individuals. Moreover, 5-lipoxygenase and leukotriene A4 hydrolase were expressed at mRNA and protein levels in vivo and in SZ95

Theodosios Alestas; Ruta Ganceviciene; Sabine Fimmel; Karin Müller-Decker; Christos C. Zouboulis

2006-01-01

136

A mass spectrometric method to determine activities of enzymes involved in polyamine catabolism.  

PubMed

An analytical method for the determination of three polyamines (putrescine, spermidine, and spermine) and five acetylpolyamines [N(1)-acetylspermidine (N(1)AcSpd), N(8)-acetylspermidine (N(8)AcSpd), N(1)-acetylspermine, N(1),N(8)-diacetylspermidine, and N(1),N(12)-diacetylspermine] involved in the polyamine catabolic pathway has been developed using a hybrid tandem mass spectrometer. Heptafluorobutyryl (HFB) derivatives of these compounds and respective internal standards labeled with stable isotopes were analyzed simultaneously by TOF MS, based on peak areas appearing at appropriate m/z values. The isomers, N(1)AcSpd and N(8)AcSpd were determined from their fragment ions, the acetylamidopropyl and acetylamidobutyl groups, respectively, using MS/MS with (13)C(2)-N(1)AcSpd and (13)C(2)-N(8)AcSpd which have the (13)C(2)-acetyl group as an internal standard. The TOF MS method was successfully applied to measure the activity of enzymes involved in polyamine catabolic pathways, namely N(1)-acetylpolyamine oxidase (APAO), spermine oxidase (SMO), and spermidine/spermine N(1)-acetyltransferase (SSAT). The following natural substrates and products labeled with stable isotopes considering the application to biological samples were identified; for APAO, [4,9,12-(15)N(3)]-N(1)-acetylspermine and [1,4,8-(15)N(3)]spermidine ((15)N(3)-Spd), respectively; for SMO, [1,4,8,12-(15)N(4)]spermine and (15)N(3)-Spd, respectively; and for SSAT, (15)N(3)-Spd and [1,4,8-(15)N(3)]-N(1)-acetylspermidine, respectively. PMID:23021806

Moriya, Shunsuke; Iwasaki, Kaori; Samejima, Keijiro; Takao, Koichi; Kohda, Kohfuku; Hiramatsu, Kyoko; Kawakita, Masao

2012-08-28

137

GSE is a maternal factor involved in active DNA demethylation in zygotes.  

PubMed

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. PMID:23560077

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

2013-04-01

138

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

139

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

140

Evidence for the involvement of p38 MAPK activation in barnacle larval settlement.  

PubMed

The barnacle Balanus (?=?Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts. PMID:23115639

He, Li-Sheng; Xu, Ying; Matsumura, Kiyotaka; Zhang, Yu; Zhang, Gen; Qi, Shu-Hua; Qian, Pei-Yuan

2012-10-24

141

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

142

Evidence that cardioprotection by postconditioning involves preservation of myocardial opioid content and selective opioid receptor activation.  

PubMed

Opioids introduced at reperfusion (R) following ischemia (I) reduce infarct size much like postconditioning, suggesting the hypothesis that postconditioning increases cardiac opioids and activates local opioid receptors. Anesthetized male rats subjected to 30 min regional I and 3 h R were postconditioned with three cycles of 10 s R and 10 s reocclusion at onset of R. Naloxone (NL), its peripherally restricted analog naloxone methiodide, delta-opioid receptor (DOR) antagonist naltrindole (NTI), kappa-opioid receptor antagonist norbinaltorphimine (NorBNI), and mu-opioid receptor (MOR) antagonist H-D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) were administered intravenously 5 min before R. The area at risk (AAR) was comparable among groups, and postconditioning reduced infarct size from 57 +/- 2 to 42 +/- 2% (P < 0.05). None of the antagonists alone altered infarct size. All antagonists abrogated postconditioning protection at higher doses. However, blockade of infarct sparing by postconditioning was lost, since tested doses of NL, NTI, NorBNI, and CTAP were lowered. The efficacy of NorBNI declined first at 3.4 micromol/kg, followed sequentially by NTI (1.1), NL (0.37), and CTAP (0.09), suggesting likely MOR and perhaps DOR participation. Representative small, intermediate, and large enkephalins in the AAR were quantified (fmol/mg protein; mean +/- SE). I/R reduced proenkephalin (58 +/- 9 vs. 33 +/- 4; P < 0.05) and sum total of measured enkephalins, including proenkephalin, peptide B, methionine-enkephalin, and methionine-enkephalin-arginine-phenylalanine (139 +/- 17 vs. 104 +/- 7; P < 0.05) compared with shams. Postconditioning increased total enkephalins (89 +/- 8 vs. 135 +/- 5; P < 0.05) largely by increasing proenkephalin (33 +/- 4 vs. 96 +/- 7; P < 0.05). Thus the infarct-sparing effect of postconditioning appeared to involve endogenously activated MORs and possibly DORs, and preservation of enkephalin precursor synthesis in the AAR. PMID:18203844

Zatta, Amanda J; Kin, Hajime; Yoshishige, Darice; Jiang, Rong; Wang, Ningping; Reeves, James G; Mykytenko, James; Guyton, Robert A; Zhao, Zhi-Qing; Caffrey, James L; Vinten-Johansen, Jakob

2008-01-18

143

Protease-Activated Receptor 2 Has Pivotal Roles in Cellular Mechanisms Involved in Experimental Periodontitis?  

PubMed Central

The tissue destruction seen in chronic periodontitis is commonly accepted to involve extensive upregulation of the host inflammatory response. Protease-activated receptor 2 (PAR-2)-null mice infected with Porphyromonas gingivalis did not display periodontal bone resorption in contrast to wild-type-infected and PAR-1-null-infected mice. Histological examination of tissues confirmed the lowered bone resorption in PAR-2-null mice and identified a substantial decrease in mast cells infiltrating the periodontal tissues of these mice. T cells from P. gingivalis-infected or immunized PAR-2-null mice proliferated less in response to antigen than those from wild-type animals. CD90 (Thy1.2) expression on CD4+ and CD8+ T-cell-receptor ? (TCR?) T cells was significantly (P < 0.001) decreased in antigen-immunized PAR-2-null mice compared to sham-immunized PAR-2-null mice; this was not observed in wild-type controls. T cells from infected or antigen-immunized PAR-2-null mice had a significantly different Th1/inflammatory cytokine profile from wild-type cells: in particular, gamma interferon, interleukins (interleukin-2, -3, and -17), granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha demonstrated lower expression than wild-type controls. The absence of PAR-2 therefore appears to substantially decrease T-cell activation and the Th1/inflammatory response. Regulation of such proinflammatory mechanisms in T cells and mast cells by PAR-2 suggests a pivotal role in the pathogenesis of the disease.

Wong, David M.; Tam, Vivian; Lam, Roselind; Walsh, Katrina A.; Tatarczuch, Liliana; Pagel, Charles N.; Reynolds, Eric C.; O'Brien-Simpson, Neil M.; Mackie, Eleanor J.; Pike, Robert N.

2010-01-01

144

Involvement of Trichoderma Trichothecenes in the Biocontrol Activity and Induction of Plant Defense-Related Genes  

PubMed Central

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.

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

2012-01-01

145

Involvement of CCR-2 chemokine receptor activation in ischemic preconditioning and postconditioning of brain in mice.  

PubMed

The present study has been designed to investigate the potential role of CCR-2 chemokine receptor in ischemic preconditioning as well as postconditioning induced reversal of ischemia-reperfusion injury in mouse brain. Bilateral carotid artery occlusion of 17 min followed by reperfusion for 24h was employed in present study to produce ischemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was evaluated using elevated plus-maze test and Morris water maze test. Rota rod test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired memory and motor co-ordination. Three preceding episodes of bilateral carotid artery occlusion for 1 min and reperfusion of 1 min were employed to elicit ischemic preconditioning of brain, while three episodes of bilateral carotid artery occlusion for 10s and reperfusion of 10s immediately after the completion of were employed to elicit ischemic postconditioning of brain. Both prior ischemic preconditioning as well as ischemic postconditioning immediately after global cerebral ischemia prevented markedly ischemia-reperfusion-induced cerebral injury as measured in terms of infarct size, loss of memory and motor coordination. RS 102895, a selective CCR-2 chemokine receptor antagonist, attenuated the neuroprotective effect of both the ischemic preconditioning as well as postconditioning. It is concluded that the neuroprotective effect of both ischemic preconditioning as well as ischemic postconditioning may involve the activation of CCR-2 chemokine receptors. PMID:22704692

Rehni, Ashish K; Singh, Thakur Gurjeet

2012-06-15

146

Residual NADPH Oxidase Activity and Isolated Lung Involvement in X-Linked Chronic Granulomatous Disease  

PubMed Central

Chronic granulomatous disease (CGD) is characterized by inherited immune defects resulting from mutations in the NADPH oxidase complex genes. The X-linked type of CGD is caused by defects in the CYBB gene that encodes gp91-phox, a fundamental component of the NADPH oxidase complex. This mutation originates the most common and severe form of CGD, which typically has absence of NADPH oxidase function and aggressive multisystemic infections. We present the case of a 9-year-old child with a rare CYBB mutation that preserves some NADPH oxidase activity, resulting in an atypical mild form of X-linked CGD with isolated lung involvement. Although the clinical picture and partially preserved oxidase function suggested an autosomal recessive form of CGD, genetic testing demonstrated a mutation in the exon 3 of CYBB gene (c.252 G>A, p.Ala84Ala), an uncommon X-linked CGD variant that affects splicing. Atypical presentation and diagnostic difficulties are discussed. This case highlights that the diagnosis of mild forms of X-linked CGD caused by rare CYBB mutations and partially preserved NADPH function should be considered early in the evaluation of atypical and recurrent lung infections.

Gutierrez, Maria J.; McSherry, George D.; Ishmael, Faoud T.; Horwitz, Alexandra A.; Nino, Gustavo

2012-01-01

147

The urokinase plasminogen activator receptor is crucially involved in host defense during acute pyelonephritis.  

PubMed

The urokinase plasminogen activator receptor (uPAR) is expressed at the cell surface of inflammatory cells and plays an important role in neutrophil migration. To investigate the in vivo role of uPAR during urinary tract infection, acute pyelonephritis was induced in uPAR-/- and wild-type (WT) mice by intravesical inoculation with 1 x 10(9) colony-forming units (CFU) of uropathogenic Escherichia coli. Mice were killed after 24 and 48 h, after which bacterial outgrowth and cytokine levels in kidney homogenates were determined. Influx of neutrophils was quantified by myeloperoxidase-enzyme-linked immunosorbent assay. uPAR-/- kidneys had significantly higher numbers of E. coli CFU, accompanied by higher levels of interleukin-1beta (IL-1beta), IL-6, keratinocyte-derived chemokine (KC), macrophage inflammatory protein-2 (MIP-2), and tumor necrosis factor-alpha (TNF-alpha). However, the number of infiltrating neutrophils was similar in uPAR-/- and WT mice at both time points, suggesting that uPAR-/- neutrophils have a lower ability to eliminate E. coli. To further investigate this, neutrophil oxidative burst and phagocytosis was measured. The generation of reactive oxygen species upon stimulation with E. coli was not diminished in uPAR-/- neutrophils compared with WT. Interestingly, uPAR-/- neutrophils displayed significantly impaired phagocytosis of E. coli organisms compared with WT neutrophils. We conclude that uPAR is crucially involved in host defense through phagocytosis during E. coli induced acute pyelonephritis. PMID:17035942

Roelofs, J J T H; Rouschop, K M A; Teske, G J D; Claessen, N; Weening, J J; van der Poll, T; Florquin, S

2006-10-11

148

Hepatitis C virus infection activates an innate pathway involving IKK-? in lipogenesis and viral assembly.  

PubMed

Hepatitis C virus (HCV) interacts extensively with host factors to not only establish productive infection but also trigger unique pathological processes. Our recent genome-wide siRNA screen demonstrated that I?B kinase-? (IKK-?) is a crucial host factor for HCV. Here we describe a new nuclear factor ?B (NF-?B)-independent and kinase-mediated nuclear function of IKK-? in HCV assembly. HCV, through its 3' untranslated region, interacts with DEAD box polypeptide 3, X-linked (DDX3X) to activate IKK-?, which translocates to the nucleus and induces a CBP/p300-mediated transcriptional program involving sterol regulatory element-binding proteins (SREBPs). This innate pathway induces lipogenic genes and enhances core-associated lipid droplet formation to facilitate viral assembly. Chemical inhibitors of IKK-? suppress HCV infection and IKK-?-induced lipogenesis, offering a proof-of-concept approach for new HCV therapeutic development. Our results show that HCV uses a novel mechanism to exploit intrinsic innate responses and hijack lipid metabolism, which may contribute to high chronicity rates and the pathological hallmark of steatosis in HCV infection. PMID:23708292

Li, Qisheng; Pčne, Véronique; Krishnamurthy, Siddharth; Cha, Helen; Liang, T Jake

2013-05-26

149

Metabolic activation and inflammation reactions involved in carbamazepine-induced liver injury.  

PubMed

Drug-induced liver injury is a major safety concern in drug development and clinical pharmacotherapy; however, advances in the understanding of the mechanisms of drug-induced liver injury are hampered by the lack of animal models. Carbamazepine (CBZ) is a widely used antiepileptic agent. Although the drug is generally well tolerated, only a small number of patients prescribed CBZ develop severe hepatitis. In the present study, we developed a mouse model of CBZ-induced liver injury and elucidated the mechanisms accounting for the hepatotoxicity of CBZ. Male BALB/c mice were orally administered CBZ for 5 days. The plasma levels of alanine aminotransferase and aspartate aminotransferase were prominently increased, and severe liver damage was observed via histological evaluation. The analysis of the plasma concentration of CBZ and its metabolites demonstrated that 3-hydroxy CBZ may be relevant in CBZ-induced liver injury. The hepatic glutathione levels were significantly decreased, and oxidative stress markers were significantly altered. Mechanistic investigations found that hepatic mRNA levels of toll-like receptor 4, receptor for advanced glycation end products, and their ligands were significantly increased. Moreover, the plasma concentrations of proinflammatory cytokines were also increased. Prostaglandin E(1) administration ameliorated the hepatic injury caused by CBZ. In conclusion, metabolic activation followed by the stimulation of immune responses was demonstrated to be involved in CBZ-induced liver injury in mice. PMID:22790970

Higuchi, Satonori; Yano, Azusa; Takai, Shohei; Tsuneyama, Koichi; Fukami, Tatsuki; Nakajima, Miki; Yokoi, Tsuyoshi

2012-07-12

150

Involvement of kinins in hyperresponsiveness induced by platelet activating factor in the human nasal airway  

PubMed Central

The aim of this study was to investigate the role of kinins in the development of nasal hyperresponsiveness induced by platelet activating factor (PAF) in normal human subjects. Intranasal administration of PAF, 60??g, induced an increased responsiveness to histamine, 200??g per nostril, 6?h later. This effect was abolished by pretreatment with the bradykinin B2 receptor antagonists icatibant and [1-adamantaneacetyl-D-Arg0,Hyp3,?-(2-thienyl)-Ala5,8,D-Phe7]-bradykinin ([Ad]-BK), both at 200??g, every 2?h following PAF administration. In a separate experiment, utilizing the same protocol, nasal lavage was used to measure the release of mediators into the nasal cavity following treatment with PAF. PAF increased the levels of eosinophil cationic protein (ECP) and kinin detected in the lavage samples, compared with a saline control. The levels of these mediators were reduced by pretreatment with either icatibant or [Ad]-BK. Administration of lyso-PAF, 60??g intranasally, did not cause a rise in kinin or ECP levels in nasal lavage fluid. Exogenous bradykinin, 500??g, or a saline control, applied topically to the nasal mucosa every 30?min for 2?h, failed to cause hyperresponsiveness to histamine. We conclude that bradykinin itself does not cause hyperresponsiveness, but is involved in the hyperresponsiveness induced by PAF in the human nasal airway.

Turner, P J; Dear, J W; Foreman, J C

2000-01-01

151

PDGF receptor tyrosine kinase inhibitor suppresses mesangial cell proliferation involving STAT3 activation  

PubMed Central

Proliferation of mesangial cells is a hallmark of glomerular disease, and understanding the regulatory mechanisms is critically important. The purpose of this study was to examine the relationship between mesangial cell proliferation and phosphorylated signal transducer and activator of transcription (STAT) 3 and to determine whether the PDGF receptor tyrosine kinase inhibitor STI 571 inhibited mesangial cell proliferation via modulation of STAT3. In this study, we investigated for the first time, the glomerular expression of phosphorylated STAT3 in paraffin sections from animals with experimental mesangial proliferative glomeronephritis. Phosphorylated STAT3 colocalized with many proliferating mesangial cells. We also demonstrated that treatment with STI 571 reduced mesangial cell proliferation and phosphorylated STAT3 signalling both in vitro and in vivo. In vivo, STI 571 treatment reduced the number of glomerular mesangial cells positive for both phosphorylated STAT3 and proliferating cell nuclear antigen. In summary, phosphorylated STAT3 is strongly expressed during mesangial cell proliferation and STI 571 induced suppression of mesangial cell proliferation involves inhibition of phosphorylated STAT3 signalling.

Hirai, T; Masaki, T; Kuratsune, M; Yorioka, N; Kohno, N

2006-01-01

152

Candidate chromosomal regions for genes involved in activation of alternative lengthening of telomeres in human immortal cell lines  

Microsoft Academic Search

Either telomerase or alternative mechanisms known as alternative lengthening of telomeres (ALT) are activated in human immortal cells to maintain or lengthen their telomeres. To screen candidate chromosomes harboring gene(s) involved in activation of the telomere maintenance mechanisms that are repressed in normal, mortal cells and lost in immortal cells, we examined loss of heterozygosity (LOH) on the 22 autosomes

Nobumasa Shigeeda; Minoru Uchida; J. Carl Barrett; Takeki Tsutsui

2003-01-01

153

Glucose-induced repression of PPAR  gene expression in pancreatic  -cells involves PP2A activation and AMPK inactivation  

Microsoft Academic Search

Tight regulation of fatty acid metabolism in pancreatic -cells is important for -cell viability and function. Chronic exposure to elevated concentrations of fatty acid is associated with -cell lipotoxicity. Glucose is known to repress fatty acid oxidation and hence to augment the toxicity of fatty acids. The peroxisome proliferator activated receptor (PPAR) is a key activator of genes involved in

Kim Ravnskjaer; Michael Boergesen; Louise T Dalgaard; Susanne Mandrup

2006-01-01

154

Obstacles and Motivators for Faculty Involvement in Grant Seeking and Grant Writing Activities in New Jersey's State College System.  

ERIC Educational Resources Information Center

|This study looked at barriers, incentives, and assistance to faculty involvement in grant-seeking and grant-writing activities on the eight campuses of the New Jersey State College System. The study surveyed a random sample of 260 faculty from the eight campuses. Of these 136 responded. Analysis found that less than 20 percent were actively

Monahan, Thomas C.

155

Activated Rho Kinase Mediates Diabetes-Induced Elevation of Vascular Arginase Activation and Contributes to Impaired Corpora Cavernosa Relaxation: Possible Involvement of p38 MAPK Activation  

PubMed Central

Introduction Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT + D), partial ROCK 2+/? knockout (KO), and ROCK 2+/? KO + D mice. Main Outcome Measures The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT + D: Emax; 61 ± 4% vs. WT: Emax; 75 ± 2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT + D mice was absent in heterozygous ROCK 2+/? KO + D mice for acetylcholine (Emax: 80 ± 5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/? KO + D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. Conclusion ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.

Nunes, Kenia P.; Yao, Lin; Liao, James K.; Webb, R. Clinton; Caldwell, Ruth B.; Caldwell, R. William

2013-01-01

156

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

Microsoft Academic Search

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

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

2011-01-01

157

Nonproteolytic serine proteinase homologs are involved in prophenoloxidase activation in the tobacco hornworm, Manduca sexta  

Microsoft Academic Search

In insects, the prophenoloxidase activation system is a defense mechanism against parasites and pathogens. Recognition of parasites or pathogens by pattern recognition receptors triggers activation of a serine proteinase cascade, leading to activation of prophenoloxidase-activating proteinase (PAP). PAP converts inactive prophenoloxidase (proPO) to active phenoloxidase (PO), which then catalyzes oxidation of phenolic compounds that can polymerize to form melanin. Because

Xiao-Qiang Yu; Haobo Jiang; Yang Wang; Michael R. Kanost

2003-01-01

158

Modafinil disrupts prepulse inhibition in mice: strain differences and involvement of dopaminergic and serotonergic activation.  

PubMed

Modafinil is a wakefulness-promoting agent with possible beneficial effects for the management of addiction and in psychiatric conditions, but also with abuse potential of its own. The mechanism of action of modafinil remains unclear. We studied pharmacological mechanisms in the effect of modafinil on prepulse inhibition (PPI), a model of sensorimotor gating. Mice were tested in automated startle boxes after administration of modafinil and antagonist drugs. Oral administration of 100mg/kg of modafinil, but not lower doses, caused a significant reduction of PPI in C57Bl/6 mice, but not Balb/c mice. This effect of modafinil could be blocked by co-treatment with the dopamine D(2) receptor antagonist, haloperidol, and the serotonin (5-HT) 2A receptor antagonist, ketanserin, but not the 5-HT(1A) receptor antagonist, WAY100,635. At 30mg/kg, which did not influence PPI, modafinil inhibited PPI disruption caused by the dopamine transporter inhibitor, GBR12909. There was no interaction between modafinil and the serotonin transporter inhibitor, fluoxetine. There were no consistent effects of modafinil on startle amplitude. These results show that oral modafinil treatment may cause disruption of PPI in mice. This effect was strain-dependent, involving dopamine D(2) and 5-HT(2A) receptor activation, and was likely mediated by an interaction with the dopamine transporter. These results extend our insight into the behavioral effects of modafinil and could be of importance for the clinical use of this agent as they may indicate an increased risk of side-effects in conditions where PPI is already reduced, such as in schizophrenia and bipolar disorder. PMID:23219987

Kwek, Perrin; van den Buuse, Maarten

2012-12-05

159

The Theory of Active Involvement: Processes Underlying Interventions That Engage Adolescents in Message Planning and/or Production.  

PubMed

Adolescence is a time of increased risk taking, and recent intervention strategies have included adolescents planning or producing antirisk messages for their peers. Although these projects may generate enthusiasm, we know little about message planning or production as a strategy for changing adolescent decision-making and behavior. This article articulates the Theory of Active Involvement (TAI) to describe and explain the processes through which these active involvement interventions influence adolescents. TAI is based on social cognitive theory's notion of self-regulation and examines multiple perspective taking and activating the self-reflection processes. The theory specifically describes the process of cognitive changes experienced by participants in active involvement interventions. The sequence is conceptualized as starting when engagement with the intervention (arousal and involvement) produces skill and knowledge gains (immediate outcomes) that lead to reflection (perceived discrepancy) and then other cognitions (expectancies, norms, intentions), with the ultimate outcome being behavior change. Engaging the target audience in a process of self-reflection is conceptualized as the crucial ingredient for meaningful and sustainable change in cognitions and behavior. This article provides valuable insight into how active involvement strategies function and how to best design these interventions, particularly those targeting adolescents. PMID:23980581

Greene, Kathryn

2013-08-27

160

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

161

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

162

Staying in or Moving Away from Structured Activities: Explanations Involving Parents and Peers  

ERIC Educational Resources Information Center

|Adolescent participation in structured activities, meaning those with adult leaders, regular meetings, and skill-building activities, is related to good adjustment. Participation in unstructured, unsupervised, peer-oriented activities is related to poor adjustment. Structured activity participation is high in early adolescence and then declines,…

Persson, Andreas; Kerr, Margaret; Stattin, Hakan

2007-01-01

163

Involvement of activated transcriptional process in efficient gene transfection using unmodified and mannose-modified bubble lipoplexes with ultrasound exposure.  

PubMed

Recently, our group developed ultrasound (US)-responsive and mannose-modified gene carriers (Man-PEG(2000) bubble lipoplexes), and successfully obtained a high level of gene expression in mannose receptor-expressing cells following gene transfection using Man-PEG(2000) bubble lipoplexes and US exposure. We also reported that large amounts of plasmid DNA (pDNA) were transferred into the cytoplasm of the targeted cells in the gene transfection using this method. In the present study, we investigated the involvement of transcriptional processes on enhanced gene expression obtained by unmodified and Man-PEG(2000) bubble lipoplexes with US exposure. The transcriptional process related to activator protein-1 (AP-1) and nuclear factor-?B (NF?B) was activated by US exposure, and was founded to be involved in enhanced gene expression obtained by gene transfection using unmodified and Man-PEG(2000) bubble lipoplexes with US exposure. On the other hand, activation of AP-1 and NF?B pathways followed by US exposure was hardly involved in the inflammatory responses in the gene transfection using this method. These findings suggest that activation of AP-1 and NF?B followed by US exposure is involved in the enhanced gene expression using unmodified and Man-PEG(2000) bubble lipoplexes with US exposure, and the selection of pDNAs activated by US exposure is important in this gene transfection method. PMID:21756951

Un, Keita; Kawakami, Shigeru; Higuchi, Yuriko; Suzuki, Ryo; Maruyama, Kazuo; Yamashita, Fumiyoshi; Hashida, Mitsuru

2011-07-03

164

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

165

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

166

Involvement in Meaningful Activities and Self-Reported Aggression and Delinquency Among Inner-City Teenagers  

Microsoft Academic Search

Ninth grade students from an inner-city high school (n = 163) completed self-report measures assessing their participation in meaningful activities, behavioral problems, and locus of control. In multivariate analyses, Gender × Activity Level interaction effects were shown: males with higher levels of meaningful activity had significantly lower scores on aggression and delinquent behavior subscales than males with lower levels of

Nancy A. Tashman; Mark D. Weist; Laura A. Nabors; Micheal E. Shafer

1998-01-01

167

Effects of ?-glutamylcysteine ethyl ester on heart mitochondrial creatine kinase activity: involvement of sulfhydryl groups  

Microsoft Academic Search

To study the mechanism of the protective effect of ?-glutamylcysteine ethyl ester, mitochondrial creatine kinase activity of rat heart was measured. ?-Glutamylcysteine ethyl ester had a protective effect against the depression of creatine kinase activity induced by xanthine+xanthine oxidase or hydrogen peroxide. ?-Glutamylcysteine ethyl ester also prevented the depression of creatine kinase activity induced by N-ethylmaleimide. It is suggested that

Hideharu Hayashi; Masaru Iimuro; Yuji Matsumoto; Masanori Kaneko

1998-01-01

168

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

Microsoft Academic Search

Our laboratory has reported on a biphasic pattern of nuclear factor kB (NF-kB) 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-kB. To further understand the

SANJEEV K. SAHNI; LOEL C. TURPIN; TRACY L. BROWN; LEE ANN SPORN

1999-01-01

169

Ca2+\\/Calmodulin-Dependent Protein Kinase Kinase Is Not Involved in Hypothalamic AMP-Activated Protein Kinase Activation by Neuroglucopenia  

Microsoft Academic Search

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

Junji Kawashima; Thierry Alquier; Youki Tsuji; Odile D. Peroni; Barbara B. Kahn

2012-01-01

170

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…

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

2007-01-01

171

Thrombopoietin regulates proliferation, apoptosis, secretory activity and intracellular messengers in porcine ovarian follicular cells: involvement of protein kinase A  

Microsoft Academic Search

Thrombopoietin (TPO) is known to be involved in megakariocytopoesis, but its role in the control of ovarian function is unknown. The aims of this study were to determine whether TPO can regulate the proliferation, apoptosis and secretory activity of ovarian cells, to identify possible intracellular mediators of TPO action, especially protein kinase A (PKA), and to define their inter- relationships

A V Sirotkin; P Sanislo; H-J Schaeffer; I Florkovicová; J Kotwica; J Bulla; L Hetényi

2004-01-01

172

Ideas Exchange: Should Students Be Granted a Waiver from Physical Education if They Are Involved in Other Activities?  

ERIC Educational Resources Information Center

|This article presents the opinions/ideas of professionals who were asked this question: "Should students be granted a waiver from physical education if they are involved in other activities?" These professionals share the pros and cons of the waiver question.|

Sipe, Roberta; Belka, David; Kamla, Jim; Christenson, Robert S.; Magnotta, John; Lorenzi, David G.

2009-01-01

173

77 FR 31045 - Order Prohibiting Involvement in NRC-Licensed Activities; In the Matter of Jaime Sánchez  

Federal Register 2010, 2011, 2012, 2013

...Involvement in NRC-Licensed Activities; In the Matter of Jaime S[aacute]nchez I Jaime S[aacute]nchez (Mr. S[aacute]nchez) is...10 CFR 30.10, it is hereby ordered that: 1. Jaime S[aacute]nchez is prohibited for 5 years...

2012-05-24

174

Ideas Exchange: Should Students Be Granted a Waiver from Physical Education if They Are Involved in Other Activities?  

ERIC Educational Resources Information Center

This article presents the opinions/ideas of professionals who were asked this question: "Should students be granted a waiver from physical education if they are involved in other activities?" These professionals share the pros and cons of the waiver question.

Sipe, Roberta; Belka, David; Kamla, Jim; Christenson, Robert S.; Magnotta, John; Lorenzi, David G.

2009-01-01

175

An Auto-regulatory loop for EBV LMP2A involves activation of Notch  

PubMed Central

LMP2A is consistently detected in Hodgkin's Lymphoma, Nasopharyngeal Carcinoma and has also been detected in Burkitt's Lymphoma. Interestingly, LMP2A is detected in the absence of the transcriptional activator EBNA2, suggesting an alternative mechanism is responsible for LMP2A expression. The intracellular domain of Notch (Notch-IC) and EBNA2 are functional homologues and recent microarray analysis indicates that LMP2A may constitutively activate the Notch pathway in vivo. Coupled with evidence that Notch-IC can bind to and activate the LMP2A promoter, we hypothesized that expression of LMP2A results in the constitutive activation of the Notch pathway to auto-regulate its promoter. Our data indicate that LMP2A constitutively activates the Notch pathway in B cells and epithelial cells. Expression of LMP2A alone is sufficient to activate its own expression and the amino-terminal signaling domain is required as LMP2B is unable to activate the LMP2A promoter. In addition, point mutations in tyrosines 31, 101 and 112 each results in a significant decrease in LMP2A promoter activation. Deletion of the RBP-J? consensus sequences results in a significant decrease in promoter activity. The observation that LMP2A activates its own promoter suggests that LMP2A exploits the Notch pathway in order to control its own expression and may explain EBNA2 independent expression of LMP2A in EBV associated malignancies.

Anderson, Leah J; Longnecker, Richard

2008-01-01

176

A review of two recent occurrences at the Advanced Test Reactor involving subcontractor activities  

Microsoft Academic Search

This report documents the results of a brief, unofficial investigation into two incidents at the Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Test Reactor (ATR) facility, reported on October 25 and 31, 1997. The first event was an unanticipated breach of confinement. The second involved reactor operation with an inoperable seismic scram subsystem, violating the reactor`s Technical Specifications. These

H. J. Dahlke; N. C. Jensen; J. A. Vail

1997-01-01

177

Do a Little Dance: The Impact on Students when Librarians Get Involved in Extracurricular Activities  

ERIC Educational Resources Information Center

|One hundred fifty-two undergraduate students at Mansfield University of Pennsylvania were surveyed to determine if the involvement of their liaison librarian in theater productions and orchestra had an effect on their relationship with the library. The study shows positive and statistically significant results for students who participated in…

Kasperek, Sheila; Johnson, Amber; Fotta, Katie; Craig, Francis

2007-01-01

178

Cyclin A\\/cdk2 Activation Is Involved in Hypoxia-Induced Apoptosis in Cardiomyocytes  

Microsoft Academic Search

Cardiomyocytes are terminally differentiated cells characterized as withdrawal cell-cycle machinery, but nonetheless they are known to express cell-cycle regulators. Because many proteins related to the cell cycle induce apoptosis in proliferating cells, we examined the involvement of these proteins in the apoptosis pathway in cardiomyocytes. Primary rat cardiomyocytes were exposed to a severe hypoxic condition to induce apoptosis. The apoptosis

Susumu Adachi; Hiroshi Ito; Mimi Tamamori-Adachi; Yuichi Ono; Toshihiro Nozato; Shinji Abe; Masa-aki Ikeda; Fumiaki Marumo; Michiaki Hiroe

179

Involvement of p38 signaling pathway in interferon-alpha-mediated antiviral activity toward hepatitis C virus.  

PubMed

We studied the involvement of the p38 signaling pathway in the interferon (IFN)-alpha-mediated antiviral activity toward hepatitis C virus (HCV) using HCV subgenomic replicon cells. When the cells were treated with IFN-alpha in the presence of p38 inhibitor, the suppressive effect of IFN-alpha on replicon RNA was reduced. Inhibition of p38 had almost no influence on phosphorylation of signal transducer and activator transcription factor 1 (STAT1) and interferon stimulatory response element-dependent gene expression after IFN-alpha treatment. This indicates that the anti-HCV activity through p38 may be independent of the Janus kinase-STAT pathway. Treatment with the inhibitor of the mitogen-activated protein kinase-activated protein kinase 2 (MK2) showed the same level of reduction in the IFN-alpha-mediated anti-HCV activity as that with the p38 inhibitor. Thus, MK2 may also be responsible for the anti-HCV activity through p38. In conclusion, the p38-MK2 signaling pathway may be substantially involved in the IFN-alpha-mediated anti-HCV activity. PMID:15358166

Ishida, Hisashi; Ohkawa, Kazuyoshi; Hosui, Atsushi; Hiramatsu, Naoki; Kanto, Tatsuya; Ueda, Keiji; Takehara, Tetsuo; Hayashi, Norio

2004-08-27

180

Changes in enzyme activities involved in malate metabolism in oak leaves during rhythmic growth  

Microsoft Academic Search

Amide content, ATP level and activities of enzymes linked to malate metabolism were determined in leaves of three successive flushes of common oak during the development of the third flush. In the expanding leaves, all studied enzymes showed a maximum activity around the 7th day after budbreak. Phosphoenolpyruvate carboxylase (PEPc), NAD-malate dehydrogenase (MDH) and NADP-malic enzyme (ME) maintained high activity

Aline Marchetti; Cécile Parmentier; Michel Chemardin; Pierre Dizengremel

1995-01-01

181

Review: Amino acid domains involved in constitutive activation of G-protein-coupled receptors  

Microsoft Academic Search

Guanine nucleotide-binding protein-coupled receptors may attain an active conformation in the absence of agonist by spontaneous\\u000a isomerization and thus yield constitutive, agonist-independent, activity. This has mainly been demonstrated for isolated membranes\\u000a and recombinant wild-type receptors, and mutant receptors. They generally show remarkable increases in the sensitivity of\\u000a a biological response. The location of activating mutations both within a single receptor

Petrus J. Pauwels; Thierry Wurch

1998-01-01

182

Tobacco Mg protoporphyrin IX methyltransferase is involved in inverse activation of Mg porphyrin and protoheme synthesis.  

PubMed

Protoporphyrin, a metabolic intermediate of tetrapyrrole biosynthesis, is metabolized by Mg chelatase and ferrochelatase and is directed into the Mg-branch for chlorophyll synthesis and in the Fe-branch for protoheme synthesis respectively. Regulation of the enzyme activities at the beginning of this branchpoint ensures accurate partition of protoporphyrin, but is still not entirely understood. Transgenic tobacco plants were generated that express antisense or sense RNA for inhibited and excessive expression of Mg protoporphyrin methyltransferase (MgPMT) respectively. This enzyme accepts Mg protoporphyrin from Mg chelatase and catalyses the transfer of a methyl group to the carboxyl group of the C13-propionate side chain. Low MgPMT activity is correlated with reduced Mg chelatase activity and a low synthesis rate of 5-aminolevulinate, but with enhanced ferrochelatase activity. In contrast, high MgPMT activity leads to inverse activity profiles: high activities of Mg chelatase and for 5-aminolevulinate synthesis, but reduced activity of ferrochelatase, indicating a direct influence of MgPMT in combination with Mg chelatase on the metabolic flux of ALA and the distribution of protoporphyrin into the branched pathway. The modified enzyme activities in tetrapyrrole biosynthesis in the transgenic plants can be explained with changes of certain corresponding mRNA contents: increased 5-aminolevulinate synthesis and Mg chelatase activity correlate with enhanced transcript levels of the HemA, Gsa, and CHLH gene encoding glutamyl-tRNA reductase, glutamate-1-semialdehyde aminotransferase and a Mg chelatase subunit respectively. It is proposed that reduced and increased MgPMT activity in chloroplasts is communicated to the cytoplasm for modulating transcriptional activities of regulatory enzymes of the pathway. PMID:15634204

Alawady, Ali E; Grimm, Bernhard

2005-01-01

183

Csk suppression of Src involves movement of Csk to sites of Src activity.  

PubMed Central

Csk phosphorylates Src family members at a key regulatory tyrosine in the C-terminal tail and suppresses their activities. It is not known whether Csk activity is regulated. To examine the features of Csk required for Src suppression, we expressed Csk mutants in a cell line with a disrupted csk gene. Expression of wild-type Csk suppressed Src, but Csk with mutations in the SH2, SH3, and catalytic domains did not suppress Src. An SH3 deletion mutant of Csk was fully active against in vitro substrates, but two SH2 domain mutants were essentially inactive. Whereas Src repressed by Csk was predominantly perinuclear, the activated Src in cells lacking Csk was localized to structures resembling podosomes. Activated mutant Src was also in podosomes, even in the presence of Csk. When Src was not active, Csk was diffusely located in the cytosol, but when Src was active, Csk colocalized with activated Src to podosomes. Csk also localizes to podosomes of cells transformed by an activated Src that lacks the major tyrosine autophosphorylation site, suggesting that the relocalization of Csk is not a consequence of the binding of the Csk SH2 domain to phosphorylated Src. A catalytically inactive Csk mutant also localized with Src to podosomes, but SH3 and SH2 domain mutants did not, suggesting that the SH3 and SH2 domains are both necessary to target Csk to places where Src is active. The failure of the catalytically active SH3 mutant of Csk to regulate Src may be due to its inability to colocalize with active Src. Images

Howell, B W; Cooper, J A

1994-01-01

184

Mitogen-Activated Protein Kinase Cascade Is Involved in Endothelin1Induced Rat Puerperal Uterine Contraction  

Microsoft Academic Search

The regulation of mitogen-activated protein (MAP) kinase by en- dothelin-1 (ET-1) in cultured rat puerperal uterine myometrial cells was investigated. ET-1 caused the rapid stimulation of MAP kinase activity. ET-1-induced MAP kinase activation is neither extracellular Ca21- nor intracellular Ca21-dependent. ET-1 stimulation also led to an increase in phosphorylation of son-of-sevenless (SOS), and trans- fection of dominant negative SOS attenuated

AKIKO KIMURA; MASAHIDE OHMICHI; TAKASHI TAKEDA; HIROHISA KURACHI; HIROMASA IKEGAMI; KOJI KOIKE; KANJI MASUHARA; JUN HAYAKAWA; TOHRU KANZAKI; MAMORU KOBAYASHI; MASUO AKABANE; MASAKI INOUE; AKIRA MIYAKE; YUJI MURATA

1999-01-01

185

Activation of AMPK by bitter melon triterpenoids involves CaMKK?.  

PubMed

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 Ca(2+)-independent. We therefore propose that CaMKK? is a key upstream kinase for BMT-induced activation of AMPK. PMID:23638033

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

2013-04-25

186

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

187

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

PubMed

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. PMID:22232165

Dall, Elfriede; Brandstetter, Hans

2011-12-24

188

Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis  

Microsoft Academic Search

Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, whereas other studies implicate the activation of the mitochondrial permeability transition pore as the mediator of

Gabriel Loor; Jyothisri Kondapalli; Jacqueline M. Schriewer; Navdeep S. Chandel; Terry L. Vanden Hoek; Paul T. Schumacker

2010-01-01

189

Discovering the Thermodynamics of Simultaneous Equilibria: An Entropy Analysis Activity Involving Consecutive Equilibria  

ERIC Educational Resources Information Center

|An activity is presented in which the thermodynamics of simultaneous, consecutive equilibria are explored. The activity is appropriate for second-year high school or AP chemistry. Students discover that a reactant-favored (entropy-diminishing or endergonic) reaction can be caused to happen if it is coupled with a product-favored reaction of…

Bindel, Thomas H.

2007-01-01

190

Family and Community Involvement in the Comprehensive School Physical Activity Program  

ERIC Educational Resources Information Center

|Engaging families and communities in physical activities for the benefit of children is an extension of the role of a physical education instructor. Although it is possible for a physical educator to generate ideas that encourage families and communities to move, a certified director of physical activity (C-DPA) would be better trained to…

Cipriani, Kristin; Richardson, Cheryl; Roberts, Georgi

2012-01-01

191

Involvement of Ras Activation in Human Breast Cancer Cell Signaling, Invasion, and Anoikis  

Microsoft Academic Search

Although mutated forms of ras are not associated with the majority of breast cancers (<5%), there is considerable experimental evidence that hyperactive Ras can promote breast cancer growth and development. Therefore, we determined whether Ras and Ras-responsive signaling pathways were activated persistently in nine widely studied human breast cancer cell lines. Although only two of the lines harbor mutationally activated

Lynn B. Eckert; Gretchen A. Repasky; Aylin S. Ulku; Aidan McFall; Hong Zhou; Carolyn I. Sartor; Channing J. Der

2004-01-01

192

Some Quantum-Mechanical Considerations in the Theory of Reactions Involving an Activation Energy  

Microsoft Academic Search

The activated complex or transition state method for calculating the absolute rate of a chemical reaction with an activation energy would be rigorously valid if classical mechanics applied to all degrees of freedom. In quantum mechanics, two kinds of limitations must be considered. First, because of Heisenberg's uncertainty principle, the transition state itself can be defined only if the potential

J. O. Hirschfelder; E. Wigner

1939-01-01

193

"Apathetic, Active, or Antagonistic": A History of the American Sociological Association's Involvement in High School Sociology  

ERIC Educational Resources Information Center

|The role that the American Sociological Association (ASA) has historically played in reforming high school sociology courses has been alternately apathetic, active, or antagonistic. Apathy marked the time period between 1905 and about 1960, and again during most of the 1970s and 1980s. The Association played a much more active role during the New…

DeCesare, Michael

2004-01-01

194

Family and Community Involvement in the Comprehensive School Physical Activity Program  

ERIC Educational Resources Information Center

Engaging families and communities in physical activities for the benefit of children is an extension of the role of a physical education instructor. Although it is possible for a physical educator to generate ideas that encourage families and communities to move, a certified director of physical activity (C-DPA) would be better trained to…

Cipriani, Kristin; Richardson, Cheryl; Roberts, Georgi

2012-01-01

195

S-nitrosohaemoglobin: a dynamic activity of blood involved in vascular control  

Microsoft Academic Search

A dynamic cycle exists in which haemoglobin is S-nitrosylated in the lung when red blood cells are oxygenated, and the NO group is released during arterial-venous transit. The vasoactivity of S-nitrosohaemoglobin is promoted by the erythrocytic export of S-nitrosothiols. These findings highlight newly discovered allosteric and electronic properties of haemoglobin that appear to be involved in the control of blood

Li Jia; Celia Bonaventura; Joseph Bonaventura; Jonathan S. Stamler

1996-01-01

196

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

197

Involvement of PRMT1 in hnRNPQ activation and internalization of insulin receptor  

Microsoft Academic Search

Insulin signaling in skeletal L6 myotubes is known to be affected by arginine methylation catalyzed by protein N-arginine methyltransferase 1 (PRMT1), however, the mechanism by which this occurs has not yet been defined. This study aimed to determine the exact substrate involved in the methylation and regulating insulin signaling in cells. Insulin enhanced arginine methylation of a 66-kDa protein (p66)

Hiroaki Iwasaki

2008-01-01

198

Cardioprotection by mild hypothermia during ischemia involves preservation of ERK activity  

Microsoft Academic Search

Cooling the ischemic heart by just a few degrees protects it from infarction without affecting its mechanical function, but\\u000a the mechanism of this protection is unknown. We investigated whether signal transduction pathways might be involved in the\\u000a anti-infarct effect of mild hypothermia (35°C). Isolated rabbit hearts underwent 30 min of coronary artery occlusion\\/2 h of\\u000a reperfusion. They were either maintained at 38.5°C

Xiulan Yang; Yanping Liu; Xi-Ming Yang; Fangdi Hu; Lin Cui; Mark R. Swingle; Richard E. Honkanen; Peyman Soltani; Renaud Tissier; Michael V. Cohen; James M. Downey

2011-01-01

199

Secretion of a lysophospholipase D activity by adipocytes: involvement in lysophosphatidic acid synthesis  

Microsoft Academic Search

The aim of the present work was to depict the met- abolic pathways involved in extracellular production of lyso- phosphatidic acid (LPA) by adipocytes. LPA was followed by quantifying the accumulation of LPA in the incubation me- dium (conditioned medium, CM) of 3T3F442A adipocytes or human adipose tissue explants using a radioenzymatic assay. Surprisingly, after separation from the cells, the

Stéphane Gesta; Marie-Françoise Simon; Astrid Rey; David Sibrac; Alexia Girard; Max Lafontan; Philippe Valet; Jean Sébastien Saulnier-Blache; Batiment L

200

Activation of Hepatic Lipase Expression by Oleic Acid: Possible Involvement of USF1  

PubMed Central

Polyunsaturated fatty acids affect gene expression mainly through peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element binding proteins (SREBPs), but how monounsaturated fatty acids affect gene expression is poorly understood. In HepG2 cells, oleate supplementation has been shown to increase secretion of hepatic lipase (HL). We hypothesized that oleate affects HL gene expression at the transcriptional level. To test this, we studied the effect of oleate on HL promoter activity using HepG2 cells and the proximal HL promoter region (700 bp). Oleate increased HL expression and promoter activity 1.3–2.1 fold and reduced SREBP activity by 50%. Downregulation of SREBP activity by incubation with cholesterol+25-hydroxycholesterol had no effect on HL promoter activity. Overexpression of SREBP2, but not SREBP1, reduced HL promoter activity, which was effected mainly through the USF1 binding site at -307/-312. Oleate increased the nuclear abundance of USF1 protein 2.7 ± 0.6 fold, while USF1 levels were reduced by SREBP2 overexpression. We conclude that oleate increases HL gene expression via USF1. USF1 may be an additional fatty acid sensor in liver cells.

van Deursen, Diederik; van Leeuwen, Marije; Akdogan, Deniz; Adams, Hadie; Jansen, Hans; Verhoeven, Adrie J.M.

2009-01-01

201

Cytolytic activity in the genus Leishmania: involvement of a putative pore-forming protein.  

PubMed Central

We describe here that parasites of the genus Leishmania contain a cytolytic activity which acts optimally at pH 5.0 to 5.5 and at 37 degrees C in vitro. or the four species examined, Leishmania (Leishmania) amazonensis and Leishmania (Leishmania) major presented considerable hemolytic activity, whereas Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis showed little and no hemolytic activity, respectively. The cytolytic factor of L. amazonensis promastigotes was characterized as a protein with no protease-, phospholipase-, or detergent-like activity, probably localized inside membranous vesicles. The use of osmotic protectants revealed the colloid-osmotic nature of hemolysis, which is indicative of pore formation in the membranes of target cells. This putative pore-forming protein also damaged nucleated cells, including macrophages, causing an increase in their membrane permeability with leakage of cytoplasmic proteins. Both promastigotes and amastigotes express this lytic activity, suggesting that the cytolysin may have a function in both stages of this parasite. The pH and temperature required for optimal activity indicate that it might be more effective within the mammalian host, particularly inside the macrophage parasitophorous vacuole. In promastigotes of L. amazonensis, the expression of lytic activity seems to be regulated during their growth in vitro, being maximal at the early stationary phase.

Noronha, F S; Ramalho-Pinto, F J; Horta, M F

1996-01-01

202

Involvement of SRE element of Ty1 transposon in TEC1-dependent transcriptional activation.  

PubMed Central

Some Ty1 transposable element insertion mutations of Saccharomyces cerevisiae activate transcription of adjacent genes in a cell-type dependent manner. This activation requires at least STE12 and TEC1 gene products. The binding site for the STE12 protein is located in the sterile responsive element (SRE), which is just downstream the 5' LTR of Ty1 and contains one copy of the pheromone response element (PRE). This report defines the sequences in Ty1 required for TEC1-dependent activation using a TDH3::lacZ reporter gene in which the UAS was replaced by different portions of a Ty1 or Ty2 element. The Ty1 SRE seems to be sufficient to ensure the TEC1 and STE12-mediated activation whereas Ty2 SRE can activate the expression of the adjacent genes in the absence of both proteins. Adjacent to the PRE element, there is a region (PAE) with extensive sequence divergence in Ty1 and Ty2 SREs. Swapping experiments between Ty1 and Ty2 sequences show that Ty1 PAE is required for the activation of adjacent gene expression in a TEC1 and STE12-dependent manner. The use of a LexA::TEC1 construct indicates that the chimeric protein has no activation ability suggesting that TEC1 could act in conjunction with another factor.

Laloux, I; Jacobs, E; Dubois, E

1994-01-01

203

Directory of DOE and contractor personnel involved in non-government standards activities  

SciTech Connect

This document contains a listing of DOE employees and DOE contractors who have submitted form DOE F 1300.2, Record of Non-Government Standards Activity. Additional names were added from rosters supplied by non-Government standards bodies.

NONE

1995-08-01

204

Mutational analysis of the major soybean UreF paralogue involved in urease activation.  

PubMed

The soybean genome duplicated ?14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO(2) in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting lack of expression/function of Ch14UreF. However, Ch02UreF and Ch14UreF transcripts accumulate at the same level. Further, it had been shown that expression of the Ch14UreF ORF complemented a fungal ureF mutant. A third, nonsense (Q2*) allelic mutant, eu2-c, exhibited 5- to 10-fold more residual urease activity than missense eu2-a or eu2-b, though eu2-c should lack all Ch02UreF protein. It is hypothesized that low-level activation by Ch14UreF is 'spoiled' by the altered missense Ch02UreF proteins ('epistatic dominant-negative'). In agreement with active 'spoiling' by eu2-b-encoded Ch02UreF (G31D), eu2-b/eu2-c heterozygotes had less than half the urease activity of eu2-c/eu2-c siblings. Ch02UreF (G31D) could spoil activation by Chr14UreF because of higher affinity for the activation complex, or because Ch02UreF (G31D) is more abundant than Ch14UreF. Here, the latter is favoured, consistent with a reported in-frame AUG in the 5' leader of Chr14UreF transcript. Translational inhibition could represent a form of 'functional divergence' of duplicated genes. PMID:21430294

Polacco, Joe C; Hyten, David L; Medeiros-Silva, Mônica; Sleper, David A; Bilyeu, Kristin D

2011-03-23

205

Mutational analysis of the major soybean UreF paralogue involved in urease activation  

PubMed Central

The soybean genome duplicated ?14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO2 in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting lack of expression/function of Ch14UreF. However, Ch02UreF and Ch14UreF transcripts accumulate at the same level. Further, it had been shown that expression of the Ch14UreF ORF complemented a fungal ureF mutant. A third, nonsense (Q2*) allelic mutant, eu2-c, exhibited 5- to 10-fold more residual urease activity than missense eu2-a or eu2-b, though eu2-c should lack all Ch02UreF protein. It is hypothesized that low-level activation by Ch14UreF is ‘spoiled’ by the altered missense Ch02UreF proteins (‘epistatic dominant-negative’). In agreement with active ‘spoiling’ by eu2-b-encoded Ch02UreF (G31D), eu2-b/eu2-c heterozygotes had less than half the urease activity of eu2-c/eu2-c siblings. Ch02UreF (G31D) could spoil activation by Chr14UreF because of higher affinity for the activation complex, or because Ch02UreF (G31D) is more abundant than Ch14UreF. Here, the latter is favoured, consistent with a reported in-frame AUG in the 5' leader of Chr14UreF transcript. Translational inhibition could represent a form of ‘functional divergence’ of duplicated genes.

Polacco, Joe C.; Hyten, David L.; Medeiros-Silva, Monica; Sleper, David A.; Bilyeu, Kristin D.

2011-01-01

206

Forest Soil Metagenome Gene Cluster Involved in Antifungal Activity Expression in Escherichia coli  

Microsoft Academic Search

Using two forest soils, we previously constructed two fosmid libraries containing 113,700 members in total. The libraries were screened to select active antifungal clones using Saccharomyces cerevisiae as a target fungus. One clone from the Yuseong pine tree rhizosphere soil library, pEAF66, showed S. cerevisiae growth inhibition. Despite an intensive effort, active chemicals were not isolated. DNA sequence analysis and

Eu Jin Chung; He Kyoung Lim; Jin-Cheol Kim; Gyung Ja Choi; Eun Jin Park; Myung Hwan Lee; Young Ryun Chung; Seon-Woo Lee

2008-01-01

207

The Ets family contains transcriptional activators and repressors involved in angiogenesis  

Microsoft Academic Search

The Ets family contains a growing number of transcriptional activators and inhibitors, which activity is regulated by phosphorylation and protein–protein interactions. Among these factors, Ets1, Erg1 and Fli1 are expressed in endothelial cells during angiogenesis in normal and pathological development. The expression of these transcription factors is regulated by angiogenic factors in cultured endothelial cells, as well as by various

Etienne Leličvre; Frédéric Lionneton; Fabrice Soncin; Bernard Vandenbunder

2001-01-01

208

Involvement of the mammillary bodies in spatial working memory revealed by cytochrome oxidase activity.  

PubMed

In view of the inconclusive findings relating the nuclei of the mammillary bodies (MB) with spatial memory, we evaluated the oxidative metabolic activity of the medial and lateral nuclei of the mammillary bodies (MB) after training young rats (30 days) of both sexes in the Morris water maze. Different groups were trained in spatial working (WM) or reference memory (RM) tasks, respectively. The corresponding naďve groups swam for the same amount of time as the trained groups but without the escape platform. Control groups were added that had not been manipulated in any way. No sex-related differences were detected in the working memory task although males exhibited better reference memory than females. Cytochrome oxidase (CO) activity, an endogenous metabolic marker for neuronal activity, was measured in all the groups. CO activity increased significantly in both MB nuclei of male and female rats only in the spatial working memory group. In addition, high CO activity in the lateral nucleus of the MB was linearly correlated with lower escape latencies in both sexes after training in the working memory task. No CO activity changes were found in the basolateral amygdala (BL) in any of the experimental groups. This nucleus was used as a control brain region because of its participation in emotional behavior. The results suggest a specific role of the MB nuclei in spatial working memory in both sexes. PMID:15140650

Conejo, Nélida M; González-Pardo, Héctor; Vallejo, Guillermo; Arias, Jorge L

2004-06-11

209

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

2013-08-20

210

AMP-activated protein kinase regulates PDGF-BB-stimulated interleukin-6 synthesis in osteoblasts: Involvement of mitogen-activated protein kinases  

Microsoft Academic Search

We have previously reported that platelet-derived growth factor (PDGF)-BB stimulates synthesis of interleukin-6 (IL-6), a potent bone resorptive agent, in osteoblast-like MC3T3-E1 cells, and that the activation of p44\\/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase\\/c-Jun N-terminal kinase (SAPK\\/JNK) is implicated in the IL-6 synthesis. In the present study, we investigated the involvement of AMP-activated protein

Kenji Kato; Takanobu Otsuka; Akira Kondo; Rie Matsushima-Nishiwaki; Hideo Natsume; Osamu Kozawa; Haruhiko Tokuda

211

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

212

Possible Dopaminergic Stimulation of Locus Coeruleus ?1-Adrenoceptors Involved in Behavioral Activation  

PubMed Central

?1-Adrenoceptors of the locus coeruleus (LC) have been implicated in behavioral activation in novel surroundings, but the endogenous agonist that activates these receptors has not been established. In addition to the canonical activation of ?1-receptors by norepinephrine (NE), there is evidence that dopamine (DA) may also activate certain brain ?1-receptors. This study examined the contribution of DA to exploratory activity in a novel cage by determining the effect of infusion of various dopaminergic and adrenergic drugs into the mouse LC. It was found that the D2/D3 agonist, quinpirole, which selectively blocks the release of CNS DA, produced a dose-dependent and virtually complete abolition of exploration and all movement in the novel cage test. The quinpirole-induced inactivity was significantly attenuated by coinfusion of DA but not by the D1 agonist, SKF38390. Furthermore, the DA attenuation of quinpirole inactivity was blocked by coinfusion of the ?1-adrenergic receptor antagonist, terazosin, but not by the D1 receptor antagonist, SCH23390. LC infusions of either quinpirole or terazosin also produced profound inactivity in DA-?-hydroxylase knockout (Dbh ?/?) mice that lack NE, indicating that their behavioral effects were not due to an alteration of the release or action of LC NE. Measurement of endogenous DA, NE, and 5HT and their metabolites in the LC during exposure to the novel cage indicated an increase in the turnover of DA and NE but not 5HT. These results indicate that DA is a candidate as an endogenous agonist for behaviorally activating LC ?1-receptors and may play a role in the activation of this nucleus by novel surroundings.

LIN, YAN; QUARTERMAIN, DAVID; DUNN, ADRIAN J.; WEINSHENKER, DAVID; STONE, ERIC A.

2009-01-01

213

Involvement of CD244 in regulating CD4+ T cell immunity in patients with active tuberculosis.  

PubMed

CD244 (2B4) is a member of the signaling lymphocyte activation molecule (SLAM) family of immune cell receptors and it plays an important role in modulating NK cell and CD8(+) T cell immunity. In this study, we investigated the expression and function of CD244/2B4 on CD4(+) T cells from active TB patients and latent infection individuals. Active TB patients had significantly elevated CD244/2B4 expression on M. tuberculosis antigen-specific CD4(+) T cells compared with latent infection individuals. The frequencies of CD244/2B4-expressing antigen-specific CD4(+) T cells were significantly higher in retreatment active TB patients than in new active TB patients. Compared with CD244/2B4-dull and -middle CD4(+) T cells, CD244/2B4-bright CD4(+) T cell subset had significantly reduced expression of IFN-?, suggesting that CD244/2B4 expression may modulate IFN-? production in M. tuberculosis antigen-responsive CD4(+) T cells. Activation of CD244/2B4 signaling by cross-linking led to significantly decreased production of IFN-?. Blockage of CD244/2B4 signaling pathway of T cells from patients with active TB resulted in significantly increased production of IFN-?, compared with isotype antibody control. In conclusion, CD244/2B4 signaling pathway has an inhibitory role on M. tuberculosis antigen-specific CD4(+) T cell function. PMID:23638187

Yang, Bingfen; Wang, Xinjing; Jiang, Jing; Cheng, Xiaoxing

2013-04-30

214

Novel orexigenic pathway prostaglandin D2-NPY system--involvement in orally active orexigenic ? opioid peptide.  

PubMed

Prostaglandin (PG) D(2), the most abundant PG in the central nervous system (CNS), is a bioactive lipid having various central actions including sleep induction, hypothermia and modulation of the pain response. We found that centrally administered PGD(2) stimulates food intake via the DP(1) among the two receptor subtypes for PGD(2) in mice. Hypothalamic mRNA expression of lipocalin-type PGD synthase (L-PGDS), which catalyzes production of PGD(2) from arachidonic acid via PGH(2) in the CNS, was increased after fasting. Central administration of antagonist and antisense ODN for the DP(1) receptor remarkably decreased food intake, body weight and fat mass. The orexigenic activity of PGD(2) was also blocked by an antagonist of Y(1) receptor for NPY, the most potent orexigenic peptide in the hypothalamus. Thus, the central PGD(2)-NPY system may play a critical role in food intake regulation under normal physiological conditions. We also found that orally active orexigenic peptide derived from food protein activates the PGD(2)-NPY system, downstream of ? opioid receptor. We revealed that the ? agonist peptide, rubiscolin-6-induced orexigenic activity was mediated by L-PGDS in the leptomeninges but not parenchyma using conditional knockout mice. In this review, we discuss the PGD(2)-NPY system itself, and orexigenic signals to activate it. PMID:23141054

Kaneko, Kentaro; Yoshikawa, Masaaki; Ohinata, Kousaku

2012-11-09

215

Lipoarabinomannan-Induced Cell Signaling Involves Ceramide and Mitogen-Activated Protein Kinase  

PubMed Central

Lipoarabinomannan (LAM) is a major cell wall-associated lipoglycan, produced in large amounts (15 mg/g of bacteria) in different species of mycobacteria. Our laboratory has previously reported that LAM from Mycobacterium smegmatis exerts its cytotoxic activity via inhibition of protein kinase C, a key signaling molecule inside the mononuclear cells (S. Ghosh, S. Pal, S. Das, S. K. Dasgupta, and S. Majumdar, FEMS Immunol. Med. Microbiol. 21:181-188, 1998). In this study we report that LAM from Mycobacterium tuberculosis induces a signal transduction pathway in favor of survivability of the host cells via the generation of ceramide, a novel second messenger. The endogenous ceramide level in mononuclear cells was found to be enhanced during LAM treatment. The effects of LAM on protein tyrosine phosphorylation in human peripheral blood mononuclear cells were examined. LAM enhanced the tyrosine phosphorylation of p42 mitogen-activated protein kinase and phosphoinositol 3-kinase (PI3 kinase) and dephosphorylation of stress-activated protein kinase. LAM-induced phosphorylation of p42 (extracellular signal-regulated kinase 2) was further enhanced by wortmannin, a PI3 kinase inhibitor. To examine whether these effects are due to elevation of endogenous ceramide, we exposed the cells to cell-permeative C2-ceramide exogenously and studied the activities of different protein kinases. Fluorescence-activated cell sorter analysis and morphological studies showed that LAM induces cell survival. Therefore, these results suggest the ability of LAM to induce ceramide in the altered signaling pathway and help in cell survival.

Sirkar, Madhumita; Majumdar, Subrata

2002-01-01

216

Involvement of Cot activity in the proliferation of ALCL lymphoma cells.  

PubMed

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. PMID:21741362

Fernández, Margarita; Manso, Rebeca; Bernaldo de Quirós, Flavia; Bernáldez, Flavia; López, Pilar; Martín-Duce, Antonio; Alemany, Susana

2011-06-29

217

Hydroxycinnamic acid decarboxylase activity of Brettanomyces bruxellensis involved in volatile phenol production: relationship with cell viability.  

PubMed

Brettanomyces bruxellensis populations have been correlated with an increase in phenolic off-flavors in wine. The volatile phenols causing the olfactory defect result from the successive decarboxylation and reduction of hydroxycinnamic acids that are normal components of red wines. The growth of B. bruxellensis is preventable by adding sulfur dioxide (SO(2)), with variable effectiveness. Moreover, it was hypothesized that SO(2) was responsible for the entry of B. bruxellensis into a viable but non-culturable (VBNC) state. The aim of this project was to investigate the effects of SO(2) on the remaining enzyme activities of B. bruxellensis populations according to their viability and cultivability, focusing on the hydroxycinnamate decarboxylase enzyme, the first enzyme needed, rather than the metabolites produced. Enzyme activity was determined both in cell-free extracts and resting cells after various SO(2) treatments in synthetic media. After slight sulfiting (around 50 mg/L total SO(2)), the yeasts had lost part of their enzyme activity but not their cultivability. At higher doses (at least 75 mg/L total SO(2)) the majority of yeasts had lost their cultivability but still retained part of their enzyme activity. These results suggested that non culturable cells retained some enzyme activity. PMID:22986185

Laforgue, R; Lonvaud-Funel, A

2012-06-28

218

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

219

Assembly of melleolide antibiotics involves a polyketide synthase with cross-coupling activity.  

PubMed

Little is known about polyketide biosynthesis in mushrooms (basidiomycota). In this study, we investigated the iterative type I polyketide synthase (PKS) ArmB of the tree pathogen Armillaria mellea, a producer of cytotoxic melleolides (i.e., polyketides esterified with various sesquiterpene alcohols). Heterologously produced ArmB showed orsellinic acid (OA) synthase activity in vitro. Further, we demonstrate cross-coupling activity of ArmB, which forms OA esters with various alcohols. Using a tricyclic Armillaria sesquiterpene alcohol, we reconstituted the biosynthesis of melledonol. Intermolecular transesterification reactions may represent a general mechanism of fungal PKSs to create structural diversity of small molecules. Phylogenetic network construction of thioesterase domains of both basidiomycetes and ascomycetes suggests that the fungal nonreducing PKS family has likely evolved from an ancient OA synthase and has gained versatility by adopting Claisen-like cyclase or transferase activity. PMID:23993460

Lackner, Gerald; Bohnert, Markus; Wick, Jonas; Hoffmeister, Dirk

2013-08-29

220

Involvement of Caspase Activation in Azaspiracid-Induced Neurotoxicity in Neocortical Neurons  

PubMed Central

Azaspiracids (AZAs) are a novel group of marine phycotoxins that have been associated with severe human intoxication. We found that AZA-1 exposure increased lactate dehydrogense (LDH) efflux in murine neocortical neurons. AZA-1 also produced nuclear condensation and stimulated caspase-3 activity with an half maximal effective concentration (EC50) value of 25.8nM. These data indicate that AZA-1 triggers neuronal death in neocortical neurons by both necrotic and apoptotic mechanisms. An evaluation of the structure-activity relationships of AZA analogs on LDH efflux and caspase-3 activation demonstrated that the full structure of AZAs was required to produce necrotic or apoptotic cell death. The similar potencies of AZA-1 to stimulate LDH efflux and caspase-3 activation and the parallel structure-activity relationships of azaspiracid analogs in the two assays are consistent with a common molecular target for both responses. To explore the molecular mechanism for AZA-1–induced neurotoxicity, we assessed the influence of AZA-1 on Ca2+ homeostasis. AZA-1 suppressed spontaneous Ca2+ oscillations (EC50 = 445nM) in neocortical neurons. A distinct structure-activity profile was found for inhibition of Ca2+ oscillations where both the full structure as well as analogs containing only the FGHI domain attached to a phenyl glycine methyl ester moiety were potent inhibitors. The molecular targets for inhibition of spontaneous Ca2+ oscillations and neurotoxicity may therefore differ. The caspase protease inhibitor Z-VAD-FMK produced a complete elimination of AZA-1–induced LDH efflux and nuclear condensation in neocortical neurons. Although the molecular target for AZA-induced neurotoxicity remains to be established, these results demonstrate that the observed neurotoxicity is dependent on a caspase signaling pathway.

Cao, Zhengyu; LePage, Keith T.; Frederick, Michael O.; Nicolaou, Kyriacos C.; Murray, Thomas F.

2010-01-01

221

Involvement of caspase activation in azaspiracid-induced neurotoxicity in neocortical neurons.  

PubMed

Azaspiracids (AZAs) are a novel group of marine phycotoxins that have been associated with severe human intoxication. We found that AZA-1 exposure increased lactate dehydrogense (LDH) efflux in murine neocortical neurons. AZA-1 also produced nuclear condensation and stimulated caspase-3 activity with an half maximal effective concentration (EC(50)) value of 25.8 nM. These data indicate that AZA-1 triggers neuronal death in neocortical neurons by both necrotic and apoptotic mechanisms. An evaluation of the structure-activity relationships of AZA analogs on LDH efflux and caspase-3 activation demonstrated that the full structure of AZAs was required to produce necrotic or apoptotic cell death. The similar potencies of AZA-1 to stimulate LDH efflux and caspase-3 activation and the parallel structure-activity relationships of azaspiracid analogs in the two assays are consistent with a common molecular target for both responses. To explore the molecular mechanism for AZA-1-induced neurotoxicity, we assessed the influence of AZA-1 on Ca(2+) homeostasis. AZA-1 suppressed spontaneous Ca(2+) oscillations (EC(50) = 445 nM) in neocortical neurons. A distinct structure-activity profile was found for inhibition of Ca(2+) oscillations where both the full structure as well as analogs containing only the FGHI domain attached to a phenyl glycine methyl ester moiety were potent inhibitors. The molecular targets for inhibition of spontaneous Ca(2+) oscillations and neurotoxicity may therefore differ. The caspase protease inhibitor Z-VAD-FMK produced a complete elimination of AZA-1-induced LDH efflux and nuclear condensation in neocortical neurons. Although the molecular target for AZA-induced neurotoxicity remains to be established, these results demonstrate that the observed neurotoxicity is dependent on a caspase signaling pathway. PMID:20047973

Cao, Zhengyu; LePage, Keith T; Frederick, Michael O; Nicolaou, Kyriacos C; Murray, Thomas F

2010-01-04

222

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

223

Involvement of membrane type 1-matrix metalloproteinase (MT1-MMP) in RAGE activation signaling pathways.  

PubMed

An advanced glycation end products (AGE)/a receptor for AGE (RAGE) axis plays a key role in diabetic vascular complications. Membrane type 1-matrix metalloproteinase (MT1-MMP) has been shown to function not only as a proteolytic enzyme but also as a signaling molecule. In this study, we investigated the role of MT1-MMP in the AGE/RAGE-triggered signaling pathways in cultured rabbit smooth muscle cells (SMCs) and the molecular interaction between RAGE and MT1-MMP in vitro and in vivo. In SMCs, AGE-activated Rac1 and p47(phox) within 1 min, NADPH oxidase activity and reactive oxygen species (ROS) generation within 5 min, and NF-?B phosphorylation within 15 min, thereby inducing redox-sensitive molecular expression. Silencing of RAGE by small-interfering RNA (siRNA) blocked the AGE-induced signaling pathways. AGE-induced geranylgeranyl transferase I (GGTase I) activity, Rac1·p47(phox) activation, NADPH oxidase activity, ROS generation, and molecular expression were also markedly attenuated by silencing of MT1-MMP. An inhibitor of GGTase I mimicked the effects of MT1-MMP-specific siRNA. Fluorescent immunohistochemistry revealed that MT1-MMP was partially co-localized with RAGE in SMCs, and RAGE was found to form a complex with MT1-MMP in both cultured SMCs and the aortae of diabetic rats by immunoprecipitation. Furthermore, MT1-MMP and RAGE formed a complex in the aortic atherosclerotic lesions of hyperlipidemic rabbits. We show that MT1-MMP plays a crucial role in RAGE-activated NADPH oxidase-dependent signaling pathways and forms a complex with RAGE in the vasculature, thus suggesting that MT1-MMP may be a novel therapeutic target for diabetic vascular complications. PMID:20945382

Kamioka, Masashi; Ishibashi, Toshiyuki; Ohkawara, Hiroshi; Nagai, Ryoji; Sugimoto, Koichi; Uekita, Hironori; Matsui, Takanori; Yamagishi, Sho-Ichi; Ando, Katsuya; Sakamoto, Takayuki; Sakamoto, Nobuo; Takuwa, Yoh; Wada, Ikuo; Shiomi, Masashi; Maruyama, Yukio; Takeishi, Yasuchika

2011-06-01

224

Activation of protein synthesis in cardiomyocytes by the hypertrophic agent phenylephrine requires the activation of ERK and involves phosphorylation of tuberous sclerosis complex 2 (TSC2).  

PubMed

The hypertrophic Gq-protein-coupled receptor agonist PE (phenylephrine) activates protein synthesis. We showed previously that activation of protein synthesis by PE requires MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] and mTOR (mammalian target of rapamycin). However, it remained unclear whether ERK activation was required and which downstream components were involved in activating mTOR and protein synthesis. Using an adenovirus encoding the MKP3 (MAPK phosphatase 3) to inhibit ERK activity, we demonstrate that ERK is essential for the activation of protein synthesis by PE. Activation and phosphorylation of S6K1 (ribosomal protein S6 kinase 1) and phosphorylation of eIF4E (eukaryotic initiation factor 4E)-binding protein (both are mTOR targets) were also inhibited by MKP3, suggesting that ERK is also required for the activation of mTOR signalling. PE stimulation of cardiomyocytes induced the phosphorylation of TSC2 (tuberous sclerosis complex 2), a negative regulator of mTOR activity. TSC2 was phosphorylated only weakly at Thr1462, but phosphorylated at additional sites within the sequence RXRXX(S/T). This differs from the phosphorylation induced by insulin, indicating that MEK/ERK signalling targets distinct sites in TSC2. This phosphorylation may be mediated by p90RSK (90 kDa ribosomal protein S6K), which is activated by ERK, and appears to involve phosphorylation at Ser1798. Activation of protein synthesis by PE is partially insensitive to the mTOR inhibitor rapamycin. Inhibition of the MAPK-interacting kinases by CGP57380 decreases the phosphorylation of eIF4E and PE-induced protein synthesis. Moreover, CGP57380+rapamycin inhibited protein synthesis to the same extent as blocking ERK activation, suggesting that MAPK-interacting kinases and regulation of mTOR each contribute to the activation of protein synthesis by PE in cardiomyocytes. PMID:15757502

Rolfe, Mark; McLeod, Laura E; Pratt, Phillip F; Proud, Christopher G

2005-06-15

225

Possible Involvement of Nitric Oxide and Reactive Oxygen Species in Glucose Deprivation-Induced Activation of Transcription Factor Rst2  

PubMed Central

Glucose is one of the most important sources of cellular nutrition and glucose deprivation induces various cellular responses. In Schizosaccharomyces pombe, zinc finger protein Rst2 is activated upon glucose deprivation, and regulates gene expression via the STREP (stress response element of Schizosaccharomyces pombe) motif. However, the activation mechanism of Rst2 is not fully understood. We monitored Rst2 transcriptional activity in living cells using a Renilla luciferase reporter system. Hydrogen peroxide (H2O2) enhanced Rst2 transcriptional activity upon glucose deprivation and free radical scavenger inhibited Rst2 transcriptional activity upon glucose deprivation. In addition, deletion of the trx2+ gene encoding mitochondrial thioredoxin enhanced Rst2 transcriptional activity. Notably, nitric oxide (NO) generators enhanced Rst2 transcriptional activity upon glucose deprivation as well as under glucose-rich conditions. Furthermore, NO specific scavenger inhibited Rst2 transcriptional activity upon glucose deprivation. Altogether, our data suggest that NO and reactive oxygen species may be involved in the activation of transcription factor Rst2.

Kato, Toshiaki; Zhou, Xin; Ma, Yan

2013-01-01

226

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

Microsoft Academic Search

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 su1 mutant in maize suggest

Chuanxin Sun; P. Sathish; Staffan Ahlandsberg; Christer Jansson

1999-01-01

227

How Curriculum Leaders Can Involve the Right Brain in Active Reading and Writing Development.  

ERIC Educational Resources Information Center

|Curriculum leaders, program specialists, and teachers can intentionally arouse the activation of one hemisphere of the brain over the other through the use of right brain strategies in language learning. While most functions of the left hemisphere are concerned with convergent production (getting the right answer), functions of the right…

Sinatra, Richard; Stahl-Gemake, Josephine

228

Involvement of p38-mitogen-activated protein kinase in staphylococcus aureus-induced neutrophil apoptosis  

Microsoft Academic Search

Apoptosis occurred in human neutro- phils within an hour of exposure to viable serum- opsonized Staphylococcus aureus, as indicated by appearance of cells with condensed nuclei, frag- mented DNA, and increased phosphatidylserine exposure. In contrast, serum-opsonized, heat- killed S. aureus did not induce apoptosis. This dis- crepancy could not be explained by differences in bacterial uptake or total NADPH-oxidase activity.

Helen Lundqvist-Gustafsson; Sara Norrman; Jessica Nilsson; Ĺsa Wilsson

2001-01-01

229

Predictors of condom use among sexually active persons involved in compulsory national service in Ibadan, Nigeria  

Microsoft Academic Search

Migration is known to increase the risk of heterosexual transmission of human immuno- deficiency virus (HIV) in sub-Saharan Africa, but little attention has been paid to fresh graduates of tertiary institutions who are on migration for compulsory national assignment in Nigeria. In July and August 2004, a survey was conducted on sexually active men (n 5 344) and women (n

Adegbenga M. Sunmola; Benjamin O. Olley; Grace E. Oso

2006-01-01

230

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

231

Developmental toxicity of testosterone in the crustacean Daphnia magna involves anti-ecdysteroidal activity  

Microsoft Academic Search

Testosterone has been shown to cause developmental arrest of embryonic daphnids (Daphnia magna). The present study was undertaken to determine whether this toxicity might be due to anti-ecdysteroidal activity associated with testosterone. The effect of testosterone on molt frequency of early instar daphnids was first evaluated to determine whether testosterone interfered with this ecdysteroid-regulated process. Molt frequency was delayed by

Xueyan Mu; Gerald A LeBlanc

2002-01-01

232

CCR7-mediated physiological lymphocyte homing involves activation of a tyrosine kinase pathway  

Microsoft Academic Search

Homing of blood-borne lymphocytes to peripheral lymph nodes (PLNs) is a multi- step process dependent on the sequen- tial engagement of L-selectin, which medi- ates lymphocyte rolling along the luminal surface of high endothelial venules (HEVs), followed by activation of lympho- cyte integrins and transmigration through HEVs. Within lymphoid tissue, B and T lymphocytes then migrate toward spe- cific microenvironments

Jens V. Stein; Silvia F. Soriano; Cesar Nombela-Arrieta; Gonzalo Gonzalez de Buitrago; JoseMiguel Rodrő ´ guez-Frade; Mario Mellado; Carlos Martínez

2002-01-01

233

Bromelain Treatment Alters Leukocyte Expression of Cell Surface Molecules Involved in Cellular Adhesion and Activation  

Microsoft Academic Search

Bromelain is a natural proteinase preparation derived from pineapple stem that is marketed for oral use as a digestive aid and as an antiinflammatory agent. Bromelain treatment in vitro has been previously shown to selectively remove certain cell surface molecules that may affect lymphocyte migration and activation. This study reports the effects of bromelain on a broad range of cell

Laura P. Hale; Paula K. Greer; Gregory D. Sempowski

2002-01-01

234

Non-T cell activation linker (NTAL): a transmembrane adaptor protein involved in immunoreceptor signaling.  

PubMed

A key molecule necessary for activation of T lymphocytes through their antigen-specific T cell receptor (TCR) is the transmembrane adaptor protein LAT (linker for activation of T cells). Upon TCR engagement, LAT becomes rapidly tyrosine phosphorylated and then serves as a scaffold organizing a multicomponent complex that is indispensable for induction of further downstream steps of the signaling cascade. Here we describe the identification and preliminary characterization of a novel transmembrane adaptor protein that is structurally and evolutionarily related to LAT and is expressed in B lymphocytes, natural killer (NK) cells, monocytes, and mast cells but not in resting T lymphocytes. This novel transmembrane adaptor protein, termed NTAL (non-T cell activation linker) is the product of a previously identified WBSCR5 gene of so far unknown function. NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl. NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking. Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells. PMID:12486104

Brdicka, Tomás; Imrich, Martin; Angelisová, Pavla; Brdicková, Nadezda; Horváth, Ondrej; Spicka, Jirí; Hilgert, Ivan; Lusková, Petra; Dráber, Petr; Novák, Petr; Engels, Niklas; Wienands, Jürgen; Simeoni, Luca; Osterreicher, Jan; Aguado, Enrique; Malissen, Marie; Schraven, Burkhart; Horejsí, Václav

2002-12-16

235

Preschool to Kindergarten Transition Activities: Involvement and Satisfaction of Families and Teachers  

Microsoft Academic Search

This paper describes a preschool to kindergarten transition project in which families and teachers participated as part of the National Center for Early Learning and Development's Kindergarten Transition Project. Over 80 high-risk children and families were followed from preschool through kindergarten. Family workers employed by the school system facilitated transition activities such as parent orientations, newsletters, and interactions with kindergarten

Karen M. La Paro; Marcia Kraft-Sayre; Robert C. Pianta

2003-01-01

236

Occurrence and activity of human intestinal bacteria involved in the conversion of dietary lignans  

Microsoft Academic Search

The human intestinal microbiota is necessary for the production of enterolignans from the dietary lignan secoisolariciresinol diglucoside (SDG). However, little is known about the bacteria that contribute to SDG conversion. Therefore, we aimed at describing the occurrence and activity of SDG metabolising bacteria. The data showed differences in conversion efficiency between SDG deglycosylating species, but SDG was completely deglycosylated within

Thomas Clavel; Daniela Borrmann; Annett Braune; Joël Doré; Michael Blaut

2006-01-01

237

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

238

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

239

The Development of Spatial Skills through Interventions Involving Block Building Activities  

ERIC Educational Resources Information Center

|This study investigated the use of block-building interventions to develop spatial-reasoning skills in kindergartners. Two intervention conditions and a control condition were included to determine, first, whether the block building activities themselves benefited children's spatial skills, and secondly, whether a story context further improved…

Casey, Beth M.; Andrews, Nicole; Schindler, Holly; Kersh, Joanne E.; Samper, Alexandra; Copley, Juanita

2008-01-01

240

From Resistance to Involvement: Examining Agency and Control in a Playworld Activity  

ERIC Educational Resources Information Center

In the recent sociocultural literature, it is possible to identify at least three ways of understanding the development of individual agency in social practices: (a) through transforming the object of activity and through self-change, (b) through responsible and intentional membership, and (c) through resistance and transformation of the dominant…

Rainio, Anna Pauliina

2008-01-01

241

Sexual Attitudes and Activities in Women with Borderline Personality Disorder Involved in Romantic Relationships  

Microsoft Academic Search

Women with Borderline Personality Disorder (BPD) are prone to have sexual relationship difficulties and dysfunctional attitudes toward sexuality. A sample of 34 heterosexual couples composed of women meeting BPD criteria was compared to a sample of dating or married women from the general population. A short form of the Sexual Activities and Attitudes Questionnaire (SAAQ) was used to measure six

Sébastien Bouchard; Natacha Godbout; Stéphane Sabourin

2009-01-01

242

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

243

Cytotoxic Activity of Schisandrolic and Isoschisandrolic Acids Involves Induction of Apoptosis  

Microsoft Academic Search

Cycloartane triterpenoid schisandrolic acid and isoschisandrolic acid were isolated from Schisandra propinqua (Wall.) Baill (Schisandraceae). Their cytotoxicity was evaluated in several cancer cell lines and primary cultured normal mouse hepatocytes. The two triterpenoids showed moderate cytotoxic activity on all tested cell lines. Fluorescence staining and cell cycle analyses were employed to elucidate the primary mechanisms of their cytotoxicity. Our results

Ze Tian; Lijia Xu; Sibao Chen; Liang Zhou; Mengsu Yang; Shilin Chen; Peigen Xiao; Erxi Wu

2007-01-01

244

Physical Activity Based Professional Development for Teachers: The Importance of Whole School Involvement  

ERIC Educational Resources Information Center

|Objective: This study sought to investigate teachers' perceptions of a physical activity-related professional development intervention. Design: Interview-based qualitative approach founded on the interpretive paradigm. Setting: Purposive selection of one high-rated independent, and one low-rated public primary school from Auckland, New Zealand.…

Till, Jude; Ferkins, Lesley; Handcock, Phil

2011-01-01

245

Tissue transglutaminase is expressed, active, and directly involved in rat dermal wound healing and angiogenesis  

Microsoft Academic Search

Tissue transglutaminase (TG) is an en- zyme that stabilizes the structure of tissues by co- valently ligating extracellular matrix molecules. Ex- pression and localization of TG are not well established during wound healing. We performed punch biopsy wounds on anesthetized rats and mon- itored the wound healing process by histological and immunohistochemical methods. The TG antigen and activity are expressed

ZISHAN A. HAROON; JOANN M. HETTASCH; THUNG-SHENQ LAI; MARK W. DEWHIRST; CHARLES S. GREENBERG

246

Functional dissection of Escherichia coli phosphotransacetylase structural domains and analysis of key compounds involved in activity regulation.  

PubMed

Escherichia coli phosphotransacetylase (Pta) catalyzes the reversible interconversion of acetyl-CoA and acetyl phosphate. Both compounds are critical in E. coli metabolism, and acetyl phosphate is also involved in the regulation of certain signal transduction pathways. Along with acetate kinase, Pta plays an important role in acetate production when E. coli grows on rich medium; alternatively, it is involved in acetate utilization at high acetate concentrations. E. coli Pta is composed of three different domains, but only the C-terminal one, called PTA_PTB, is specific for all Ptas. In the present work, the characterization of E. coli Pta and deletions from the N-terminal region were performed. E. coli Pta acetyl phosphate-forming and acetyl phosphate-consuming reactions display different maximum activities, and are differentially regulated by pyruvate and phosphoenolpyruvate. These compounds activate acetyl phosphate production, but inhibit acetyl-CoA production, thus playing a critical role in defining the rates of the two Pta reactions. The characterization of three truncated Ptas, which all display Pta activity, indicates that the substrate-binding site is located at the C-terminal PTA_PTB domain. However, the N-terminal P-loop NTPase domain is involved in expression of the maximal catalytic activity, stabilization of the hexameric native state, and Pta activity regulation by NADH, ATP, phosphoenolpyruvate, and pyruvate. The truncated protein Pta-F3 was able to complement the growth on acetate of an E. coli mutant defective in acetyl-CoA synthetase and Pta, indicating that, although not regulated by metabolites, the Pta C-terminal domain is active in vivo. PMID:20236319

Campos-Bermudez, Valeria Alina; Bologna, Federico Pablo; Andreo, Carlos Santiago; Drincovich, María Fabiana

2010-03-08

247

Vasorelaxation by hydrogen sulphide involves activation of Kv7 potassium channels.  

PubMed

Hydrogen sulphide (H2S) has been recently hypothesized to be an endogenous adipocyte-derived relaxing factor, evoking vasorelaxation of conductance and resistance vessels. Although the activation of ATP-sensitive potassium channels is known to play a central role in H2S-induced vasorelaxation, activation of vascular Kv7 voltage-gated potassium channels has also been suggested. To investigate this possibility, the ability of selective activators and blockers of distinct classes of potassium channels to affect vasodilation induced by the H2S-donor NaHS, as well as NaHS-induced Rb(+) efflux in endothelium-denuded rat aortic rings, was investigated. NaHS-induced changes of membrane potential were fluorimetrically assessed on human vascular smooth muscle (VSM) cells. Modulation of Kv7.4 channels by NaHS was assessed by electrophysiological studies, upon their heterologous expression in CHO cells. In isolated aortic rings, NaHS evoked vasorelaxing responses associated with an increase of Rb(+)-efflux. NaHS promoted membrane hyperpolarization of human VSM cells. These effects were antagonized by selective blockers of Kv7 channels. The H2S-donor caused a left-shift of current activation threshold of Kv7.4 channels expressed in CHO cells. Altogether, these results suggest that the activation of Kv7.4 channels is a key mechanism in the vascular effects of H2S. Given the relevant roles played by Kv7.4 channels in VSM contractility and by H2S in circulatory homeostasis regulation, these findings provide interesting insights to improve our understanding of H2S pathophysiology and to focus on Kv7.4 channels as novel targets for therapeutic approaches via the "H2S-system". PMID:23287425

Martelli, A; Testai, L; Breschi, M C; Lawson, K; McKay, N G; Miceli, F; Taglialatela, M; Calderone, V

2013-01-01

248

Covert signal disruption: anti-ecdysteroidal activity of bisphenol A involves cross talk between signaling pathways.  

PubMed

Bisphenol A is a key industrial chemical used in the manufacture of polycarbonate plastics and other products. Several recent reports ascribe toxicological properties to this compound that have been attributed to the disruption of endocrine-related processes. In the present study, the toxicity of bisphenol A was definitively characterized in the water flea (Daphnia magna) in an effort to discern whether this compound may elicit endocrine toxicity in an invertebrate species and to establish the mechanism by which this toxicity is elicited. The ability of bisphenol A to interfere with two ecdysteroid-dependent physiological processes--molting and embryonic development--was evaluated. Bisphenol A elicited antiecdysteroidal activity as indicated by its prolongation of the intermolt period and interference with embryonic development. This apparent antiecdysteroidal activity was not due to reduced availability of endogenous ecdysteroid nor due to ecdysteroid-receptor antagonism. The ability of bisphenol A to elicit antiecdysteroidal activity by functioning as a juvenoid hormone was next evaluated. Bisphenol A, alone, did not elicit juvenoid activity. However, bisphenol A did enhance the activity of the crustacean juvenoid hormone methyl farnesoate. A definitive assessment of the effects of bisphenol A on the reproductive capacity of daphnids revealed a concentration-response relationship that extended at least one order of magnitude below exposure levels that were overtly toxic to the maternal organisms. These results demonstrate that bisphenol A is chronically toxic to daphnids, probably through its ability to interfere with ecdysteroid/juvenoid regulated processes. However, effects are elicited at levels that are not likely to pose environmental concern. PMID:15683178

Mu, Xueyan; Rider, Cynthia V; Hwang, Gap Soo; Hoy, Heather; LeBlanc, Gerald A

2005-01-01

249

No evidence for a putative involvement of platelet-activating factor in systemic lupus erythematosus without active nephritis.  

PubMed Central

BACKGROUND: Platelet-activating factor (PAF) seems to be implicated in systemic lupus erythematosus (SLE) patients with associated renal diseases. AIMS: In this study, we ensured the role of PAF in SLE patients without renal complications. METHODS: Blood PAF and acetylhydrolase activity, plasma soluble phospholipase A(2), and the presence of antibodies against PAF were investigated in 17 SLE patients without active nephritis and in 17 healthy controls. RESULTS: Blood PAF levels were not different (p=0.45) between SLE patients (6.7+/-2.8 pg/ml) and healthy subjects (9.6+/-3.1 pg/ml). Plasma acetylhydrolase activity (the PAF-degrading enzyme) was significantly (p=0.03) elevated in SLE patients (57.8+/-6.4 nmol/min/ml) as compared with controls (37.9+/-2.6 nmol/min/ml). Plasma soluble phospholipase A(2) (the key enzyme for PAF formation) was not different (p=0.6) between SLE patients (59.1+/-5.1 U/ml) and controls (54.7+/-2.4 U/ml). Antibodies against PAF were detected only in 3/17 SLE patients. Flow cytometry analysis did not highlight PAF receptors on circulating leukocytes of SLE patients. CONCLUSION: This clinical study highlights no evidence for a putative important role of PAF in SLE patients without active nephritis.

Denizot, Yves; Liozon, Eric; Guglielmi, Laurence; Ly, Kim; Soria, Pascale; Loustaud, Veronique; Vidal, Elisabeth; Jauberteau, Marie Odile

2003-01-01

250

Neuropharmacological activity of the pericarp of Passiflora edulis flavicarpa degener: putative involvement of C-glycosylflavonoids.  

PubMed

Passiflora edulis has been used in traditional medicine as a sedative and to treat or prevent central disorders such as anxiety and insomnia. In this study, the central effects of the aqueous extract (AE), the butanolic fraction (BF), and the aqueous residual fraction (ARF) obtained from the pericarp of P. edulis flavicarpa were investigated in mice and the possible compounds involved in these putative neuropharmacologic effects were determined. AE, BF, and ARF increased the total time spent in the light compartment of the light:dark box, an anxiolytic-like effect, and AE also potentiated the hypnotic effects of ethyl ether, a sedative effect. The thin layer chromatography and high-performance liquid chromatography analysis indicated the predominance of C-glycosylflavonoids in these extracts and fractions, which were identified as isoorientin, vicenin-2, spinosin, and 6,8-di-C-glycosylchrysin. PMID:19491371

Sena, Ligia Moreiras; Zucolotto, Silvana Maria; Reginatto, Flávio Henrique; Schenkel, Eloir Paulo; De Lima, Thereza Christina Monteiro

2009-06-02

251

Antioxidants in treating pathologies involving oxidative damage: an update on medicinal chemistry and biological activity of stobadine and related pyridoindoles.  

PubMed

Pathologies involving oxidative stress are indicative of malfunction of endogenous antioxidant capacity. Numerous efforts were made to design and synthesize biologically active antioxidants and free oxygen radical scavenging substances that could improve the endogenous antioxidant status. The antioxidant and reactive-oxygen-species-scavenging activity of STB was well demonstrated in many in vitro and in vivo studies. These properties of STB seem to be closely related to its beneficial effects in models of oxidative-stress-involving pathologies, including myocardial infarction, stroke, neurodegenerative disorders, hypoxic-ischemic tissue injury, diabetic complications, chronic inflammation, etc. STB has a good affinity to lipids and exerts its protective activity against free-radical-mediated damage by preventing lipid peroxidation. Rather than interacting with the radicals initiating lipid peroxidation, STB was shown to act in its propagation stage via scavenging peroxyl and/or alkoxyl radicals. STB was also found to protect proteins, predominantly by a mechanism involving protection of thiol groups and by preventing oxidation of amino acids. The first findings on antioxidant and pharmacodynamic effects of STB, tested in a variety of biological models, were summarized in 1998. Recently, chemical modification of STB, which we considered as the leading structure, led to the synthesis of pyridoindole derivatives with significantly increased intrinsic antiradical activity and overall antioxidant efficacy compared to the parental molecule. The present paper provides a complete overview of the literature published since 1998 on both STB and STB congeners. Moreover, appropriate structural modifications of STB provided the opportunity to modulate lipophilicity and acidobasic behavior, thus optimizing bioavailability of the novel derivatives and attenuating their unwanted sideeffects, with the result of decreased toxicity. Hence, STB congeners might be prospectively used as medicinal antioxidants, i.e. remedies effective in conditions involving oxidative stress-mediated injury. PMID:20015031

Juranek, I; Horakova, L; Rackova, L; Stefek, M

2010-01-01

252

Changes of the activities of enzymes involved in prostaglandin synthesis in rat skin during development and aging  

Microsoft Academic Search

The developmental changes of enzymes involved in prostaglandin (PG) synthesis were investigated in rat skin from birth to 1.5 years old. In all stages of development, the activities of PG-synthesizing enzymes were found in 100,000xg supernatants of homogenates of rat skin, and PGD2 was the major PG among those formed from PGH2 in the presence of 1 md glutathione (GSH).

K. Ikai; M. Ujihara; Y. Urade

1989-01-01

253

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

254

Phosphoinositide 3-kinase and integrin signalling are involved in activation of Bruton tyrosine kinase in thrombin-stimulated platelets.  

PubMed

Bruton tyrosine kinase (Btk) plays a crucial role in the differentiation of B lymphocytes and belongs to the group of Tec kinases, which are characterised by the presence of a pleckstrin homology domain. Here we show that Btk is activated and undergoes tyrosine phosphorylation upon challenge of platelet thrombin receptor, these responses requiring engagement of alphaIIb/beta3 integrin and phosphoinositide 3-kinase activity. These data unravel a novel signalling pathway involving Btk downstream of an adhesive receptor via a complex regulation implicating the products of phosphoinositide 3-kinase, which might act to anchor Btk at the membrane. PMID:9928954

Laffargue, M; Ragab-Thomas, J M; Ragab, A; Tuech, J; Missy, K; Monnereau, L; Blank, U; Plantavid, M; Payrastre, B; Raynal, P; Chap, H

1999-01-22

255

TNF-? has tropic rather than apoptotic activity in human hematopoietic progenitors: involvement of TNF receptor-1 and caspase-8.  

PubMed

Tumor necrosis factor-? (TNF-?) has been suggested to exert detrimental effects on hematopoietic progenitor function that might limit the success of transplants. In this study, we assessed the influences of TNF-? and its two cognate receptors on the function of fresh umbilical cord blood (UCB) and cryopreserved mobilized peripheral blood (mPB). CD34(+) progenitors from both sources are less susceptible to spontaneous apoptosis than lineage-committed cells and are not induced into apoptosis by TNF-?. Consequently, the activity of UCB-derived severe combined immune deficiency (SCID) reconstituting cells and long-term culture-initiating cells is unaffected by this cytokine. On the contrary, transient exposure of cells from both sources to TNF-? stimulates the activity of myeloid progenitors, which persists in vivo in UCB cell transplants. Progenitor stimulation is selectively mediated by TNF-R1 and involves activation of caspase-8, without redundant activity of TNF-R2. Despite significant differences between fresh UCB cells and cryopreserved mPB cells in susceptibility to apoptosis and time to activation, TNF-? is primarily involved in tropic signaling in hematopoietic progenitors from both sources. Cytokine-mediated tropism cautions against TNF-? neutralization under conditions of stress hematopoiesis and may be particularly beneficial in overcoming the limitations of UCB cell transplants. PMID:23081800

Mizrahi, Keren; Stein, Jerry; Yaniv, Isaac; Kaplan, Offer; Askenasy, Nadir

2013-01-01

256

Cardiac ischemia activates vascular endothelial cadherin promoter in both preexisting vascular cells and bone marrow cells involved in neovascularization.  

PubMed

Vascular endothelial cadherin (VE-cadherin) is expressed on vascular endothelial cells, which are involved in developmental vessel formation. However, it remains elusive how VE-cadherin-expressing cells function in postnatal neovascularization. To trace VE-cadherin-expressing cells, we developed mice expressing either green fluorescent protein or LacZ driven by VE-cadherin promoter using Cre-loxP system. Although VE-cadherin promoter is less active after birth than during embryogenesis in blood vessels, it is reactivated on cardiac ischemia. Both types of reporter-positive cells are found in the vasculature and in the infarcted myocardium. Those found in the vasculature were pre-existing endothelial cells and incorporated endothelial progenitor cells derived from extracardiac tissue. In addition to the vasculature, VE-cadherin promoter-activated cells were positive for CD45 in the bone marrow cells of the infarcted mice. VE-cadherin promoter-reactivated CD45-positive leukocytes were also found in the infarcted area. In addition, VE-cadherin promoter was activated in the bone marrow vessels of the infarcted mice. Collectively, our findings reveal a new ischemia-induced neovascularization mechanism involving VE-cadherin; the re-expressed VE-cadherin-mediated cell adhesion between cells may be involved not only in homing of bone marrow-derived cells to ischemic area but also mobilization from bone marrow. PMID:16543497

Kogata, Naoko; Arai, Yuji; Pearson, James T; Hashimoto, Kazuaki; Hidaka, Kyoko; Koyama, Tatsuya; Somekawa, Satoshi; Nakaoka, Yoshikazu; Ogawa, Minetaro; Adams, Ralf H; Okada, Masato; Mochizuki, Naoki

2006-03-16

257

Candidate chromosomal regions for genes involved in activation of alternative lengthening of telomeres in human immortal cell lines.  

PubMed

Either telomerase or alternative mechanisms known as alternative lengthening of telomeres (ALT) are activated in human immortal cells to maintain or lengthen their telomeres. To screen candidate chromosomes harboring gene(s) involved in activation of the telomere maintenance mechanisms that are repressed in normal, mortal cells and lost in immortal cells, we examined loss of heterozygosity (LOH) on the 22 autosomes and the X chromosome in 22 in vitro established human immortal cell lines consisting of 9 telomerase-positive cell lines and 13 ALT-positive cell lines. For detecting LOH, PCR analysis was performed with 66 polymorphic microsatellite markers from candidate genomic regions previously implicated for putative human senescence genes, telomerase repressor genes, or tumor suppressor genes. LOH involving chromosome 8 was observed at 25 of 62 (40%) informative loci in 8 of 13 (61%) ALT-positive cell lines. Particularly, when assayed with D8S339 adjacent to the Werner's syndrome gene, LOH was found in 6 of 12 (50%) informative ALT-positive cell lines. In contrast, no LOH on chromosome 8 was detected at 41 informative loci in any of 9 telomerase-positive cell lines. No other chromosomes showed high frequencies of LOH common in either ALT-positive or telomerase-positive cell lines. Although further LOH analysis with additional markers remains to define the specific region on chromosome 8, our results suggest that gene(s) involved in activation of the ALT pathway in human immortal cell lines may localize on chromosome 8. PMID:12814799

Shigeeda, Nobumasa; Uchida, Minoru; Barrett, J Carl; Tsutsui, Takeki

2003-06-01

258

Pannexin-1 influences peritoneal cavity cell population but is not involved in NLRP3 inflammasome activation.  

PubMed

Pannexin-1 (Panx1) forms nonselective large channel in cell plasma membrane and has been shown to be associated with NLRP3 inflammasome activation, ATP release and phagocytes recruitment. In the current study, by manipulation of Panx1 expression in human myeloid cells and application of Panx1 deficient mice, we failed to find a correlation between Panx1 and NLRP3 inflammasome activation, although an interaction between these two proteins was evident. However, in thioglycollate induced peritonitis, Panx1 deficient mice showed much more phagocytes infiltration. Further analyses showed that mice deficient for Panx1 exhibited enlarged F4/80(low)Gr1(-)Ly6C(-)cell population in the peritonea. Our study thus reveals an important role for Panx1 in regulation of peritoneal cell population and peritonitis development. PMID:23549611

Wang, Hongbin; Xing, Yue; Mao, Liming; Luo, Yi; Kang, Lishan; Meng, Guangxun

2013-04-03

259

Cadmium activities of silver-cadmium alloys determined from measurements on emf cells involving displacement reactions  

SciTech Connect

Cadmium activities have been obtained for dilute solutions of silver in cadmium at 776 K from emf measurements using the cell: W-Cd/CdI' + Cd (A/sub Cd/ = 1) parallels CdI'' + AgI + Cd (a/sub Cd/) < 1)/Cd, Ag-W. When the displacement reaction 2Ag + CdI'' i Cd + 2AgI is taken into account, the calculated cadmium activities follow the equation a/sub Cd/ = 1 - N/sub Ab/ - 0.607 N''/sub Ag/ with a standard deviation of 0.00001 for those measurements (taken by the most precise method) used in the least squares fit. The largest deviation from the curve for all points measured was 0.0006 or 0.9 g/cal in G/sub Cd/.

Houseman, B.L.; Conant, D.R.

1984-01-01

260

Involvement of ASK1 activation in apoptosis induced by NPe6-PDT  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) employing photosensiter N-aspartyl chlorin e6 (NPe6) can induce lysosome disruption and initiate apoptotic pathway. Apoptosis signal-regulating kinase (ASK1) is an important regulator of apoptosis in response to various stresses, such as reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, lipopolysaccharide (LPS) and calcium influx. In this study, we investigated the molecular mechanisms of apoptosis induced by NPe6-PDT in ASTC-a-1 cells. The results showed that the activities of ASK1 increased in response to NPe6-PDT. Over-expression of wild-type or activated mutant of ASK1 could obviously decrease cell viability and increase cell death; while inhibition of ASK1 significantly decreased cell apoptosis. These results suggested that ASK1 plays an important role in apoptosis induced by NPe6-PDT.

Liu, Lei; Zhang, Zhen-Zhen; Zhang, Zhigang

2010-02-01

261

Involvement of protein-tyrosine phosphorylation and dephosphorylation in sperm-induced Xenopus egg activation  

Microsoft Academic Search

We have analyzed tyrosine-phosphorylated proteins in Xenopus laevis eggs before and after fertilization by immunoblotting with anti-phosphotyrosine antibody. A number of egg proteins with different subcellular distribution became tyrosine-phosphorylated or dephosphorylated within 30 min after insemination. Tyrosine kinase-specific inhibitors genistein and herbimycin A were found to inhibit sperm-induced egg activation judged by the egg cortical contraction. Surprisingly, sodium orthovanadate, a

Ken-ichi Sato; Tetsushi Iwasaki; Ikuo Tamaki; Mamoru Aoto; Alexander A Tokmakov; Yasuo Fukami

1998-01-01

262

Involvement of cyclin dependent kinase5 activator p25 on tau phosphorylation in mouse brain  

Microsoft Academic Search

P35 or its truncated fragment p25 is required for cyclin dependent kinase (Cdk)5 activation. It has been reported that p25 is accumulated in the brain of Alzheimer's disease (AD) patients and that p25\\/Cdk5 induces high phosphorylation of tau and apoptosis in cultured neurons (Nature 402 (1999) 615). Our investigation of AD brain did not show specific accumulation of p25. Exposure

Akihiko Takashima; Miyuki Murayama; Kaori Yasutake; Hiroshi Takahashi; Minesuke Yokoyama; Koichi Ishiguro

2001-01-01

263

A new interaction between Abi-1 and ?PIX involved in PDGF-activated actin cytoskeleton reorganisation  

Microsoft Academic Search

Members of the Rho family of GTPases are key regulators of the actin cytoskeleton. In particular, activated Rac1 stimulates membrane dorsal ruffle formation in response to platelet-derived growth factor (PDGF). Abl-interactor (Abi)-1 and ?PIX, a guanine nucleotide exchange factor for Rac1, localise at these Rac1-induced actin structures and play important roles in the induction of membrane dorsal ruffling in response

Fanny Campa; Nikolaus Machuy; Alexander Klein; Thomas Rudel

2006-01-01

264

Nalidixic Acid Resistance: A Second Genetic Character Involved in DNA Gyrase Activity  

Microsoft Academic Search

ATP-dependent DNA supercoiling catalyzed by Escherichia coli DNA gyrase was inhibited by oxolinic acid, a compound similar to but more potent than nalidixic acid and a known inhibitor of DNA replication in E. coli. The supercoiling activity of DNA gyrase purified from nalidixic acid-resistant mutant (nalAR) bacteria was resistant to oxolinic acid. Thus, the nalA locus is responsible for a

Martin Gellert; Kiyoshi Mizuuchi; Mary H. O'Dea; Tateo Itoh; Jun-Ichi Tomizawa

1977-01-01

265

Involvement of intracellular Ca 2+ in oxidant-induced NF-?B activation  

Microsoft Academic Search

In human Jurkat T cells and its subclone Wurzburg cells oxidant challenge elevated [Ca2+]i by mobilizing Ca2+ from intracellular stores. In Jurkat cells this effect was rapid and transient, but in Wurzburg cells the response was slow and sustained. H202-induced NF-?B activation in Wurzburg cells was not influenced by the presence of extracellular EGTA but was totally inhibited in cells

Chandan K. Sen; Sashwati Roy; Lester Packer

1996-01-01

266

Involvement of an Active Efflux System in the Natural Resistance of Pseudomonas aeruginosa to Aminoglycosides  

Microsoft Academic Search

A mutant, named 11B, hypersusceptible to aminoglycosides, tetracycline, and erythromycin was isolated after Tn501 insertion mutagenesis of Pseudomonas aeruginosa PAO1. Cloning and sequencing experiments showed that 11B was deficient in an, at that time, unknown active efflux system that contains homologs of MexAB. This locus also contained a putative regulatory gene, mexZ, transcribed divergently from the efflux operon. Introduction of

JULIO RAMOS AIRES; THILO KOHLER; HIROSHI NIKAIDO; PATRICK PLESIAT

267

Involvement of protein trafficking in deprenyl-induced ?-secretase activity regulation in PC12 cells  

Microsoft Academic Search

Deprenyl is a selective B-type monoamine oxidase inhibitor and a neuroprotective agent that has been used to slow the progress of Alzheimer's disease for many years. We previously demonstrated that deprenyl could stem amyloid precursor protein processing (APP) toward the non-amyloidogenic pathway through mitogen activated protein kinase (MAPK) and protein kinase C (PKC)-dependent signaling pathways [Yang, H.Q., Ba, M.W., Ren,

Hong-Qi Yang; Zhi-Kun Sun; Mao-Wen Ba; Jun Xu; Ying Xing

2009-01-01

268

Relief of Dyspnea Involves a Characteristic Brain Activation and a Specific Quality of Sensation  

Microsoft Academic Search

Rationale: Central processing of dyspnea relief remains largely un- known. Objectives: To identify physiologic determinants, quality of sensa- tion, and brain activation associated with dyspnea relief. Methods: Dyspnea relief was induced in 10 healthy volunteers by decreasing an adjustable external resistive load (z15-50 cm H2O\\/L\\/s). Brain imaging (positron emission tomography) was performed dur- ing either dyspnea or relief. Measurements and

Claudine Peiffer; Nicolas Costes; Philippe Herve ´; Luis Garcia-Larrea

269

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

270

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

271

Glucose-Induced Regulation of NHEs Activity and SGLTs Expression Involves the PKA Signaling Pathway  

Microsoft Academic Search

The effect of glucose on the intracellular pH (pHi) recovery rate (dpHi\\/dt) and Na+-glucose transporter (SGLT) localization was investigated in HEK-293 cells, a cell line that expresses endogenous NHE1, NHE3,\\u000a SGLT1, and SGLT2 proteins. The activity of the Na+\\/H+ exchangers (NHEs) was evaluated by using fluorescence microscopy. The total and membrane protein expression levels were analyzed\\u000a by immunoblotting. In cells

Olívia Beloto-Silva; Ubiratan Fabres Machado; Maria Oliveira-Souza

2011-01-01

272

Regulation of GABAA receptor in cerebellar granule cells in culture: differential involvement of kinase activities.  

PubMed

GABAA receptor function was studied in rat cerebellar granule cells in culture, by the whole-cell patch-clamp approach. The data show that GABA activates Cl- currents in these neurons which reverse at the appropriate membrane potential and are blocked by picrotoxin. The GABA-activated currents desensitize with time of application of the neurotransmitter at concentrations > or = 10(-6) M. The dose-response curve for the peak Cl- current gives a Ka value of 2.3 microM with a Hill coefficient of 1.2. The peak Cl- current elicited by GABA decreases with time of cell registration, with a time-constant of 7.3 min. Residual responsiveness though is maintained thereafter. This "run-down" phenomenon can be completely prevented by adding adenosine-5'-triphosphate + Mg2+ in the pipette solution. Treatments which directly (8-bromoadenosine-3',5'-cyclic-monophosphate; adenosine-3', 5'-cyclic-monophosphate) or indirectly (forskolin, isobutylmethylxanthine) increase the adenosine-3',5'-cyclic-monophosphate intracellular content reduce the GABA-induced Cl- current. Conversely, treatment with the protein kinase A and C inhibitor 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine potentiates the effect of GABA. On the whole, the data indicate that different protein kinase activities modulate the functional state of the GABAA receptors on granule cells from the rat cerebellum. PMID:7682295

Robello, M; Amico, C; Cupello, A

1993-03-01

273

Intracellular Cysteine 346 Is Essentially Involved in Regulating Panx1 Channel Activity*  

PubMed Central

Pannexins constitute a family of proteins exhibiting predominantly hemichannel activity. Pannexin channels have been suggested to participate in a wide spectrum of biological functions such as propagation of calcium waves, release of IL-1?, and responses to ischemic conditions. At present, the molecular mechanisms regulating pannexin hemichannel activity are essentially unknown. Because cysteines have been shown to constitute key elements in regulating hemichannel properties of the connexin-type we performed site-directed mutagenesis of intracellular cysteine residues of Panx1. Cysteine to serine exchange (Cys ? Ser) at the C-terminal position amino acid 346 led to a constitutively leaky hemichannel and subsequently to cell death. Increased channel activity was demonstrated by dye uptake and electrophysiological profiling in injected Xenopus laevis oocytes and transfected N2A cells. Mutations of the remaining intracellular cysteines did not result in major changes of Panx1 channel properties. From these data we conclude that the Cys-346 residue is important for proper functioning of the Panx1 channel.

Bunse, Stefanie; Schmidt, Matthias; Prochnow, Nora; Zoidl, Georg; Dermietzel, Rolf

2010-01-01

274

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

275

Cisplatin nephrotoxicity involves mitochondrial injury with impaired tubular mitochondrial enzyme activity.  

PubMed

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. PMID:22511597

Zsengellér, Zsuzsanna K; Ellezian, Lena; Brown, Dan; Horváth, Béla; Mukhopadhyay, Partha; Kalyanaraman, Balaraman; Parikh, Samir M; Karumanchi, S Ananth; Stillman, Isaac E; Pacher, Pál

2012-04-17

276

A molecular mechanism for mimosine-induced apoptosis involving oxidative stress and mitochondrial activation.  

PubMed

Mimosine, a non-protein amino acid, is mainly known for its action as a reversible inhibitor of DNA replication and, therefore, has been widely used as a cell cycle synchronizing agent. Recently, it has been shown that mimosine also induces apoptosis, as mainly reflected in its ability to elicit characteristic nuclear changes. The present study elucidates the mechanism underlying mimosine's apoptotic effects, using the U-937 leukemia cell line. We now demonstrate that in isolated rat liver mitochondria, mimosine induces mitochondrial swelling that can be inhibited by cyclosporine A, indicative of permeability transition (PT) mega-channel opening. Mimosine-induced apoptosis was accompanied by formation of hydrogen peroxide and a decrease in reduced glutathione levels. The apoptotic process was partially inhibited by cyclosporine A and substantially blocked by the antioxidant N-acetylcysteine, suggesting an essential role for reactive oxygen species formation during the apoptotic processes. The apoptosis induced by mimosine was also accompanied by a decrease in mitochondrial membrane potential, cytochrome c release and caspase 3 and 9 activation. Our results thus imply that mimosine activates apoptosis through mitochondrial activation and formation of H2O2, both of which play functional roles in the induction of cell death. PMID:18058236

Hallak, Maher; Vazana, Liat; Shpilberg, Ofer; Levy, Itai; Mazar, Julia; Nathan, Ilana

2008-01-01

277

A polysaccharide from Armillaria mellea exhibits strong in vitro anticancer activity via apoptosis-involved mechanisms.  

PubMed

Armillaria mellea is a famous traditional Chinese medicinal and edible fungus. In this study, we purified a water-soluble polysaccharide (AMP) from the fruiting bodies of this fungus. AMP contained 94.8% carbohydrate, 2.3% uronic acid and 0.5% protein. Its molecular weight was determined as 4.6 × 10? Da, as determined by high-performance gel-permeation chromatography (HPGPC). Gas chromatography (GC) analysis indicated that AMP was mainly composed of d-glucose. In vitro assay, AMP exhibited a potent tumor growth inhibitory effect on A549 cells, and induced cell cycle disruption in the G0/G1 phase, accompanied by an increment of apoptotic cells. Furthermore, AMP induced the disruption of mitochondrial membrane potential, thus leading to cytochrome c release from mitochondria and activation of caspase-3 and -9. Taken together, our results demonstrate that AMP possesses strong antitumor activities through the mitochondria dependent pathway and activation of caspase cascade through cytochrome c release. PMID:22771925

Wu, Jun; Zhou, Jinxu; Lang, Yaoguo; Yao, Lei; Xu, Hai; Shi, Hubo; Xu, Shidong

2012-07-03

278

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

279

Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts.  

PubMed

At 5 microgram/ml, insulin stimulates hexose, A-system amino acid, and nucleoside transport by serum-starved chick embryo fibroblasts (CEF). This stimulation, although variable, is comparable to that induced by 4% serum. The sulfhydryl oxidants diamide (1-20 micrometer). hydrogen peroxide (500 micrometer), and methylene blue (50 micrometer) mimic the effect of insulin in CEF. PCMB-S,1 a sulfhydryl-reacting compound which penetrates the membrane slowly, has a complex effect on nutrient transport in serum- and glucose-starved CEF. Hexose uptake is inhibited by 0.1-1 mM PCMB-S in a time- and concentration-dependent manner, whereas A-system amino acid transport is inhibited maximally within 10 min of incubation and approaches control rates after 60 min. A differential sensitivity of CEF transport systems is also seen in cells exposed to membrane-impermeant glutathione-maleimide I, designated GS-Mal. At 2 mM GS-Mal reduces the rate of hexose uptake 80-100% in serum- and glucose-starved CEF; in contrast A-system amino acid uptake is unaffected. D-glucose, but not -L-glucose or cytochalasin B, protects against GS-Mal inhibition. These results are consistent with the hypothesis that sulfhydryl groups are involved in nutrient transport and that those sulfhydryls associated with the hexose transport system and essential for its function are located near the exofacial surface of the membrane in CEF. PMID:564429

Smith-Johannsen, H; Perdue, J F; Ramjeesingh, M; Kahlenberg, A

1977-01-01

280

Involvement of PRMT1 in hnRNPQ activation and internalization of insulin receptor.  

PubMed

Insulin signaling in skeletal L6 myotubes is known to be affected by arginine methylation catalyzed by protein N-arginine methyltransferase 1 (PRMT1), however, the mechanism by which this occurs has not yet been defined. This study aimed to determine the exact substrate involved in the methylation and regulating insulin signaling in cells. Insulin enhanced arginine methylation of a 66-kDa protein (p66) concomitant with translocation of PRMT1 to the membrane fraction. Peptide mass fingerprinting identified p66 as a heterogeneous nuclear ribonucleoprotein, hnRNPQ that was bound to and methylated by PRMT1. Pharmacological inhibition of methylation (MTA) and small interfering RNA against PRMT1 (PRMT1-siRNA) attenuated insulin-stimulated tyrosine phosphorylation of hnRNPQ and insulin receptor (IR), and the interaction between hnRNPQ and IR. MTA, PRMT1-siRNA, and hnRNPQ-siRNA inhibited internalization of IR in the same manner. These data suggest that the PRMT1-mediated methylation of hnRNPQ is implicated in IR trafficking and insulin signaling in skeletal L6 myotubes. PMID:18492485

Iwasaki, Hiroaki

2008-05-19

281

Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis.  

PubMed

Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, whereas other studies implicate the activation of the mitochondrial permeability transition pore as the mediator of cell death. We investigated menadione-induced cell death in genetically modified cells lacking specific death-associated proteins. In cardiomyocytes, oxidant stress was assessed using the redox sensor RoGFP, expressed in the cytosol or the mitochondrial matrix. Menadione elicited rapid oxidation in both compartments, whereas it decreased mitochondrial potential and triggered cytochrome c redistribution to the cytosol. Cell death was attenuated by N-acetylcysteine and exogenous glutathione or by overexpression of cytosolic or mitochondria-targeted catalase. By contrast, no protection was observed in cells overexpressing Cu,Zn-SOD or Mn-SOD. Overexpression of antiapoptotic Bcl-X(L) protected against staurosporine-induced cell death, but it failed to confer protection against menadione. Genetic deletion of Bax and Bak, cytochrome c, cyclophilin D, or caspase-9 conferred no protection against menadione-induced cell death. However, cells lacking PARP-1 showed a significant decrease in menadione-induced cell death. Thus, menadione induces cell death through the generation of oxidant stress in multiple subcellular compartments, yet cytochrome c, Bax/Bak, caspase-9, and cyclophilin D are dispensable for cell death in this model. These studies suggest that multiple redundant cell death pathways are activated by menadione, but that PARP plays an essential role in mediating each of them. PMID:20937380

Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M; Chandel, Navdeep S; Vanden Hoek, Terry L; Schumacker, Paul T

2010-10-27

282

Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis  

PubMed Central

Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, while other studies implicate activation of the mitochondrial permeability transition poreas the mediator of cell death. We investigated menadione-induced cell death in genetically modified cells lacking specific death-associated proteins. In cardiomyocytes, oxidant stress was assessed using the redox sensor RoGFP, expressed in the cytosol or the mitochondrial matrix. Menadione elicited rapid oxidation in both compartments, while it decreased mitochondrial potential and triggered cytochrome c redistribution to the cytosol. Cell death was attenuated by N-acetyl cysteine and exogenous glutathione (GSH), or by over-expression of cytosolic or mitochondria-targeted catalase. By contrast, no protection was observed in cells over-expressing Cu, Zn-SOD or MnSOD. Over-expression of antiapoptotic Bcl-XLprotected against staurosporine-induced cell death, but it failed to confer protection against menadione. Genetic deletion of Bax and Bak, cytochrome c, cyclophilin D or caspase-9 conferred no protection against menadione-induced cell death. However, cells lacking PARP-1 showed a significant decrease in menadione-induced cell death. Thus, menadione induces cell death through the generation of oxidant stress in multiple subcellular compartments, yet cytochromec, Bax/Bak, caspase-9 and cyclophilin D are dispensable for cell death in this model. These studies suggest that multiple redundant cell death pathways are activated by menadione, but that PARP plays an essential role in mediating each of them.

Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M.; Chandel, Navdeep S.; Vanden Hoek, Terry L.; Schumacker, Paul T.

2010-01-01

283

Calcium-Sensing Receptor Activation of Rho Involves Filamin and Rho-Guanine Nucleotide Exchange Factor  

Microsoft Academic Search

We investigated the role of Gq, filamin, Rho, the RhoGEF Lbc, and the C terminus of calcium-sensing receptor (CasR) in CasR signaling. We found that Ca2 ,M g 2, or the calcimimetic R iso- mer of N-(3-(2-chlorophenyl)propyl)-(R)--methyl-3-methoxy- benzylamine (NPS-R568) stimulated serum response element (SRE) activity human embryonic kidney 293 cells transfected with CasR and an SRE-luciferase reporter construct. Coexpres- sion

MIN PI; ROBERT F. SPURNEY; QISHENG TU; TODD HINSON; L. DARRYL QUARLES

2002-01-01

284

Activation of red cell Ca2(+)-activated K+ channel by Ca2+ involves a temperature-dependent step.  

PubMed

We found that vanadate-induced 45Ca2+ uptake by red cells is maximal at 25 degrees C. At this temperature, the Cai-induced increase of the K+ permeability (the Gárdos effect) shows a lag (up to 8 min) which is not observed at 37 degrees C. This cannot be explained by the lack of availability of Ca2+ for the Ca2(+)-activated K+ channel, and suggests that its activation by Ca2+ is mediated by a temperature-dependent mechanism which remains unknown so far. The lag is not observed when the Gárdos effect was initiated by propranolol. This shows that the putative temperature-dependent step is different from chloride transport. PMID:2265697

Varecka, L; Peterajová, E

1990-12-10

285

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

286

Activation of phospholipase A(2) by long chain fatty acyl groups involves a novel unstable linkage.  

PubMed

The acidic isoform of phospholipase A(2) from Naja mossambica mossambica was activated by treatment with a molar equivalent of oleoyl imidazolide. Modification of the protein was accompanied by 50% quenching of tryptophan fluorescence and a significant red shift. The (3)H(9,10) labeled oleoyl residue was co-eluted with the enzyme during gel filtration in the presence of 20% 1-propanol or excess albumin, both of which remove free oleic acid from the enzyme. In contrast, the adduct was labile as to electrophoresis on SDS-PAGE and acid or alkali urea PAGE. The formation of a covalently linked adduct was demonstrated by electrospray mass spectrometry in the presence of 2% formic acid. No such adduct was formed by the phospholipase A(2) isoform from Naja naja atra, which differs in sequence from the N. mossambica mossambica isoform by seven residues including 2 histidine residues and 1 lysine residue. We conclude that oleoyl imidazolide activates the N. mossambica mossambica enzyme by forming an acyl adduct which is unstable as to protein denaturation. The magnitude of tryptophan fluorescence quenching indicates that the site of acylation lies in the sequence WWHF. PMID:10788797

Ahmed, T; Kelly, S M; Price, N C; Lawrence, A J

2000-05-01

287

Involvement of MAPK activation in chemokine or COX-2 productions by Toxoplasma gondii  

PubMed Central

This experiment focused on MAPK activation in host cell invasion and replication of T. gondii, as well as the expression of CC chemokines, MCP-1 and MIP-1?, and enzyme, COX-2/prostaglandin E2 (PGE2) in infected cells via western blot, [3H]-uracil incorporation assay, ELISA and RT-PCR. The phosphorylation of ERK1/2 and p38 in infected HeLa cells was detected at 1 hr and/or 6 hr postinfection (PI). Tachyzoite proliferation was reduced by p38 or JNK MAPK inhibitors. MCP-1 secretion was enhanced in infected peritoneal macrophages at 6 hr PI. MIP-1? mRNA was increased in macrophages at 18 hr PI. MCP-1 and MIP-1? were reduced after treatment with inhibitors of ERK1/2 and JNK MAPKs. COX-2 mRNA gradually increased in infected RAW 264.7 cells and the secretion of COX-2 peaked at 6 hr PI. The inhibitor of JNK suppressed COX-2 expression. PGE2 from infected RAW 264.7 cells was increased and synthesis was suppressed by PD98059, SB203580, and SP600125. In this study, the activation of p38, JNK and/or ERK1/2 MAPKs occurred during the invasion and proliferation of T. gondii tachyzoites in HeLa cells. Also, increased secretion and expression of MCP-1, MIP-1?, COX-2 and PGE2 were detected in infected macrophages, and appeared to occur via MAPK signaling pathways.

Kim, Ji-Young; Song, Hyun-Ouk; Choi, Jong-Hak; Ryu, Jae-Sook; Min, Duk-Young; Cho, Myung-Hwan

2006-01-01

288

Transferrin Binding to Peripheral Blood Lymphocytes Activated by Phytohemagglutinin Involves a Specific Receptor  

PubMed Central

Immunohistological studies have indicated that membrane sites binding transferrin are present upon activated human peripheral blood lymphocytes. In this study, we have investigated transferrin uptake in human lymphocytes exposed to phytohemagglutinin (PHA), by quantitative radiobinding and immunofluorescence in parallel. In stimulated lymphocytes, binding was maximal after a 30-min incubation, being greatest at 37°C, and greater at 22°C than at 4°C. Although some shedding and endocytosis of transferrin occurred at 22° and 37°C, these factors, and resulting synthesis of new sites, did not affect measurement of binding which was found to be saturable, reversible, and specific for transferrin (Ka 0.5-2.5 × 108 M?1). Binding was greater after a 48-h exposure to PHA than after 24 h, and was maximal at 66 h. Sequential Scatchard analysis revealed no significant elevation in affinity of interaction. However, although the total number of receptors increased, the proportion of cells in which binding of ligand was detected immunohistologically increased in parallel, and after appropriate correction, the cellular density of receptors remained relatively constant throughout (60,000-80,000 sites/cell). Increments in binding during the culture period were thus due predominantly to expansion of a population of cells bearing receptors. Similar differences in binding were apparent upon comparison of cells cultured in different doses of PHA, and in unstimulated cells binding was negligible. Transferrin receptors appear, therefore, to be readily detectable only upon lymphocytes that have been activated. Images

Galbraith, Robert M.; Werner, Phillip; Arnaud, Philippe; Galbraith, Gillian M. P.

1980-01-01

289

FasL Expression in Activated T Lymphocytes Involves HuR-mediated Stabilization*  

PubMed Central

A prolonged activation of the immune system is one of the main causes of hyperproliferation of lymphocytes leading to defects in immune tolerance and autoimmune diseases. Fas ligand (FasL), a member of the TNF superfamily, plays a crucial role in controlling this excessive lymphoproliferation by inducing apoptosis in T cells leading to their rapid elimination. Here, we establish that posttranscriptional regulation is part of the molecular mechanisms that modulate FasL expression, and we show that in activated T cells FasL mRNA is stable. Our sequence analysis indicates that the FasL 3?-untranslated region (UTR) contains two AU-rich elements (AREs) that are similar in sequence and structure to those present in the 3?-UTR of TNF? mRNA. Through these AREs, the FasL mRNA forms a complex with the RNA-binding protein HuR both in vitro and ex vivo. Knocking down HuR in HEK 293 cells prevented the phorbol 12-myristate 13-acetate-induced expression of a GFP reporter construct fused to the FasL 3?-UTR. Collectively, our data demonstrate that the posttranscriptional regulation of FasL mRNA by HuR represents a novel mechanism that could play a key role in the maintenance and proper functioning of the immune system.

Drury, Gillian L.; Di Marco, Sergio; Dormoy-Raclet, Virginie; Desbarats, Julie; Gallouzi, Imed-Eddine

2010-01-01

290

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

291

Human prolactin (hPRL) antagonists inhibit hPRL-activated signaling pathways involved in breast cancer cell proliferation.  

PubMed

The involvement of human prolactin (hPRL) in breast cancer has been recently reconsidered based on its autocrine/paracrine proliferative effect described in human mammary tumor epithelial cells. Therefore, there is growing interest in the development of potent hPRL antagonists that may inhibit this effect. We previously designed hPRL analogs displaying antagonistic properties in a human transcriptional bioassay. We now report that the most potent of those analogs, G129R-hPRL, antagonizes all hPRL-induced effects analysed in various breast cancer cell lines, including cell proliferation. The analog per se lacks intrinsic agonistic activity on PRL receptor-activated signaling cascades, cell proliferation and apoptosis, indicating that its mode of action only occurs through competitive inhibition of hPRL. We provide some molecular basis of this antagonistic effect by demonstrating that G129R-hPRL competitively inhibits hPRL-activation of the JAK-STAT and MAPK pathways, two signaling cascades involved in the mitogenic effect of hPRL in mammary epithelial cells. This competitive inhibition persists for at least 48 h, as evidenced by long term analysis of STAT5b activation or of progression through cell cycle. These results are the first demonstration at the molecular level that hPRL antagonists interfering with receptor dimerization disrupt signaling events in breast cancer cells, which prevents hPRL-induced cell proliferation. PMID:11032019

Llovera, M; Pichard, C; Bernichtein, S; Jeay, S; Touraine, P; Kelly, P A; Goffin, V

2000-09-28

292

Muscarinic receptor-activated signal transduction pathways involved in the neuritogenic effect of astrocytes in hippocampal neurons  

PubMed Central

Astrocytes have been shown to release factors that affect various aspects of neuronal development. We have previously shown that the acetylcholine analogue carbachol, by activating muscarinic M3 receptors in rat astrocytes, increases their ability to promote neuritogenesis in hippocampal neurons. This effect was mediated by an increased expression and release by astrocytes of several permissive factors, a most relevant of which was fibronectin. In the present study we investigated the signal transduction pathways involved in these effects of carbachol in astrocytes. Results show that multiple pathways are involved in the effects of carbachol on astrocyte-mediated increases in fibronectin expression and neuritogenesis. These include the phospholipase D pathway, leading to sequential activation of protein kinase C (PKC) ?, p70S6 kinase and nuclear factor-?B; the phosphoinositide- 3 kinase pathway; and the PKC ? pathway leading to activation of mitogen activated protein kinase. These pathways were shown to mediate the effect of carbachol on neurite outgrowth as well as the increased expression of fibronectin, further substantiating the important role of the latter in astrocyte-mediated neuritogenesis. Interference with these signaling pathways would be expected to impair astrocyte-neurons communication leading to impaired neuronal development.

Guizzetti, Marina; Moore, Nadia H.; VanDeMark, Kathryn L.; Giordano, Gennaro; Costa, Lucio G.

2011-01-01

293

Involvement of protein kinase C in 5-HT-stimulated ciliary activity in Helisoma trivolvis embryos  

PubMed Central

During development, embryos of the pulmonate gastropod, Helisoma trivolvis, undergo a rotation behaviour due to the co-ordinated beating of three bands of ciliated epithelial cells. This behaviour is in part mediated by the neurotransmitter serotonin (5-HT) released from a pair of identified embryonic neurons. Using time-lapse videomicroscopy to measure ciliary beat frequency (CBF) in response to pharmacological manipulations, we determined whether protein kinase C (PKC) is involved in mediating 5-HT-stimulated ciliary beating.Diacylglycerol (DAG) analogues sn-1,2-dioctanoyl glycerol (DiC8; 100 ?M) and 1-oleoyl-2-acetyl-sn-glycerol (OAG; 100 ?M), partially mimicked the 5-HT-induced increase in CBF. In contrast, application of OAG in the absence of extracellular Ca2+ did not result in an increase in CBF.5-HT-stimulated CBF was effectively blocked by PKC inhibitors bisindolylmaleimide (10 and 100 nM) and calphostin C (10 nM). In addition, bisindolylmaleimide (100 nM) inhibited DiC8-induced increases in CBF. At a higher concentration (200 nM), bisindolylmaleimide did not significantly reduce 5-HT-stimulated cilio-excitation.Two different phorbol esters, phorbol 12-myristate 13-acetate (TPA; 0.1, 10 or 1000 nM) and phorbol 12?, 13?-dibenzoate (PDBn; 10 ?M) did not alter basal CBF. TPA (1 ?M) did not alter 5-HT-stimulated CBF. Likewise, the synthetic form of phosphatidylserine, N-(6-phenylhexyl)-5-chloro-1-naphthalenesulphonamide (SC-9; 10 ?M), did not increase CBF, whereas a strong increase in CBF was observed upon exposure to 5-HT.The results suggest that a DAG-dependent, phorbol ester-insensitive isoform of PKC mediates 5-HT-stimulated CBF in ciliated epithelial cells from embryos of Helisoma trivolvis.

Christopher, Kimberley J; Young, Kevin G; Chang, John P; Goldberg, Jeffrey I

1999-01-01

294

Elevated Insulin Secretion from Liver X Receptor-Activated Pancreatic ?-Cells Involves Increased de Novo Lipid Synthesis and Triacylglyceride Turnover  

PubMed Central

Increased basal and loss of glucose-stimulated insulin secretion (GSIS) are hallmarks of ?-cell dysfunction associated with type 2 diabetes. It has been proposed that elevated glucose promotes insulin secretory defects by activating sterol regulatory element binding protein (SREBP)-1c, lipogenic gene expression, and neutral lipid storage. Activation of liver X receptors (LXRs) also activates SREBP-1c and increases lipogenic gene expression and neutral lipid storage but increases basal and GSIS. This study was designed to characterize the changes in de novo fatty acid and triacylglyceride (TAG) synthesis in LXR-activated ?-cells and determine how these changes contribute to elevated basal and GSIS. Treatment of INS-1 ?-cells with LXR agonist T0901317 and elevated glucose led to markedly increased nuclear localization of SREBP-1, lipogenic gene expression, de novo synthesis of monounsaturated fatty acids and TAG, and basal and GSIS. LXR-activated cells had increased fatty acid oxidation and expression of genes involved in mitochondrial ?-oxidation, particularly carnitine palmitoyltransferase-1. Increased basal insulin release from LXR-activated cells coincided with rapid turnover of newly synthesized TAG and required acyl-coenzyme A synthesis and mitochondrial ?-oxidation. GSIS from LXR-activated INS-1 cells required influx of extracellular calcium and lipolysis, suggesting production of lipid-signaling molecules from TAG. Inhibition of diacylglyceride (DAG)-binding proteins, but not classic isoforms of protein kinase C, attenuated GSIS from LXR-activated INS-1 cells. In conclusion, LXR activation in ?-cells exposed to elevated glucose concentrations increases de novo TAG synthesis; subsequent lipolysis produces free fatty acids and DAG, which are oxidized to increase basal insulin release and activate DAG-binding proteins to enhance GSIS, respectively.

Green, Christopher D.; Jump, Donald B.; Olson, L. Karl

2009-01-01

295

Antimicrobial activity of lysozyme against bacteria involved in food spoilage and food-borne disease.  

PubMed Central

Egg white lysozyme was demonstrated to have antibacterial activity against organisms of concern in food safety, including Listeria monocytogenes and certain strains of Clostridium botulinum. We also found that the food spoilage thermophile Clostridium thermosaccharolyticum was highly susceptible to lysozyme and confirmed that the spoilage organisms Bacillus stearothermophilus and Clostridium tyrobutyricum were also extremely sensitive. Several gram-positive and gram-negative pathogens isolated from food poisoning outbreaks, including Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, Campylobacter jejuni, Escherichia coli O157:H7, Salmonella typhimurium, and Yersinia enterocolitica, were all resistant. The results of this study suggest that lysozyme may have selected applications in food preservation, especially when thermophilic sporeformers are problems, and as a safeguard against food poisoning caused by C. botulinum and L. monocytogenes.

Hughey, V L; Johnson, E A

1987-01-01

296

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

297

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

298

Interionic and intermolecular interactions in ion-exchange and sorption systems involving physiologically active substances  

SciTech Connect

This paper reviews the results obtained by studying the sorption of physiologically active substances (PAS) of different types such as, amino acids, nucleotides and melanoidins on ion exchangers and non-ionogenic sorbents. The review is mainly focused upon the mechanisms of interaction of PAS molecules in the sorbent phase. The contribution of ion-ionic, ion-molecular and intermolecular interactions to the overall sorption effect is discussed. The results of studying ion-exchange isothermal supersaturation of amino acid solutions on anion exchangers are reported and discussed. The mechanisms of aging of ion-exchange materials in the course of recovery of PAS from fermentation broths and hydrolysates are proposed. 48 refs.

Selemenev, V.F.; Chikin, G.A.; Khokhlov, V.J.

1999-07-01

299

Involvement of Nrf2 signaling pathway in the neuroprotective activity of natural kaurane diterpenes.  

PubMed

Oxidative stress is a common harmful condition of several neurodegenerative diseases. Antioxidants represent the medical choice strategy for protection against this unbalanced oxidant-antioxidant status. The present study was undertaken to address the role of kaurane diterpenes foliol, linearol and sidol in the protection against H(2)O(2)-induced oxidative stress in the human astrocytoma U373-MG cell line and to establish the underlying mechanisms. U373-MG cells were pretreated with diterpenes (5 and 10 ?M, 24h) prior to H(2)O(2) exposition (1mM, 30 min). We found that linearol and sidol exerted a significant astroprotective action, and foliol was the least active one. Linearol and sidol especially increased cell viability as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and lactate dehydrogenase assay and attenuated morphological changes of U373-MG cells induced by H(2)O(2). Moreover, these compounds significantly decreased the level of intracellular reactive oxygen species, counteracted glutathione/oxidized glutathione changes, reduced lipid peroxidation and restored antioxidant and protein expression of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase and hemooxigenase-1). Furthermore, these natural products increased Nrf2 nuclear levels, suggesting the activation of this master regulator of antioxidative gene expressions in the protective effect exhibited by the kaurane diterpenes studied. Collectively, these results suggest that the studied kaurane diterpenes, mainly linearol and sidol, protect U373-MG cells from H(2)O(2)-induced injury or degeneration presumably by antioxidant mechanisms. These compounds may be useful agents for counteracting the oxidative damage occurring during the pathological development of several CNS disorders. PMID:23079631

González-Burgos, E; Carretero, M E; Gómez-Serranillos, M P

2012-10-16

300

Mesenchymal glioma stem cells are maintained by activated glycolytic metabolism involving aldehyde dehydrogenase 1A3  

PubMed Central

Tumor heterogeneity of high-grade glioma (HGG) is recognized by four clinically relevant subtypes based on core gene signatures. However, molecular signaling in glioma stem cells (GSCs) in individual HGG subtypes is poorly characterized. Here we identified and characterized two mutually exclusive GSC subtypes with distinct dysregulated signaling pathways. Analysis of mRNA profiles distinguished proneural (PN) from mesenchymal (Mes) GSCs and revealed a pronounced correlation with the corresponding PN or Mes HGGs. Mes GSCs displayed more aggressive phenotypes in vitro and as intracranial xenografts in mice. Further, Mes GSCs were markedly resistant to radiation compared with PN GSCs. The glycolytic pathway, comprising aldehyde dehydrogenase (ALDH) family genes and in particular ALDH1A3, were enriched in Mes GSCs. Glycolytic activity and ALDH activity were significantly elevated in Mes GSCs but not in PN GSCs. Expression of ALDH1A3 was also increased in clinical HGG compared with low-grade glioma or normal brain tissue. Moreover, inhibition of ALDH1A3 attenuated the growth of Mes but not PN GSCs. Last, radiation treatment of PN GSCs up-regulated Mes-associated markers and down-regulated PN-associated markers, whereas inhibition of ALDH1A3 attenuated an irradiation-induced gain of Mes identity in PN GSCs. Taken together, our data suggest that two subtypes of GSCs, harboring distinct metabolic signaling pathways, represent intertumoral glioma heterogeneity and highlight previously unidentified roles of ALDH1A3-associated signaling that promotes aberrant proliferation of Mes HGGs and GSCs. Inhibition of ALDH1A3-mediated pathways therefore might provide a promising therapeutic approach for a subset of HGGs with the Mes signature.

Mao, Ping; Joshi, Kaushal; Li, Jianfeng; Kim, Sung-Hak; Li, Peipei; Santana-Santos, Lucas; Luthra, Soumya; Chandran, Uma R.; Benos, Panayiotis V.; Smith, Luke; Wang, Maode; Hu, Bo; Cheng, Shi-Yuan; Sobol, Robert W.; Nakano, Ichiro

2013-01-01

301

Glucose-induced regulation of NHEs activity and SGLTs expression involves the PKA signaling pathway.  

PubMed

The effect of glucose on the intracellular pH (pH(i)) recovery rate (dpH(i)/dt) and Na(+)-glucose transporter (SGLT) localization was investigated in HEK-293 cells, a cell line that expresses endogenous NHE1, NHE3, SGLT1, and SGLT2 proteins. The activity of the Na(+)/H(+) exchangers (NHEs) was evaluated by using fluorescence microscopy. The total and membrane protein expression levels were analyzed by immunoblotting. In cells cultivated in 5 mM glucose, the pH(i) recovery rate was 0.169 ± 0.020 (n = 6). This value did not change in response to the acute presence of glucose at 2 or 10 mM, but decreased with 25 mM glucose, an effect that was not observed with 25 mM mannitol. Conversely, the chronic effect of high glucose (25 mM) increased the pH(i) recovery rate (~40%, P < 0.05), without changes in the total levels of NHE1, NHE3, or SGLT1 expression, but increasing the total cellular (~50%, P < 0.05) and the plasma membrane (~100%, P < 0.01) content of SGLT2. Treatment with H-89 (10(-6) M) prevented the stimulatory effect of chronic glucose treatment on the pH(i) recovery rate and SGLT2 expression in the plasma membrane. Our results indicate that the effect of chronic treatment with a high glucose concentration is associated with increased NHEs activity and plasma membrane expression of SGLT2 in a protein kinase A-dependent way. The present results reveal mechanisms of glucotoxicity and may contribute to understanding the diabetes-induced damage of this renal epithelial cell. PMID:21140140

Beloto-Silva, Olívia; Machado, Ubiratan Fabres; Oliveira-Souza, Maria

2010-12-08

302

Fnr Is Involved in Oxygen Control of Herbaspirillum seropedicae N-Truncated NifA Protein Activity in Escherichia coli  

PubMed Central

Herbaspirillum seropedicae is an endophytic diazotroph belonging to the ?-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.

Monteiro, Rose A.; de Souza, Emanuel M.; Yates, M. Geoffrey; Pedrosa, Fabio O.; Chubatsu, Leda S.

2003-01-01

303

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

304

Activity-dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen.  

PubMed

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-box(TIR) (SCF(TIR)) 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. PMID:21289280

Baba, Kyoko; Karlberg, Anna; Schmidt, Julien; Schrader, Jarmo; Hvidsten, Torgeir R; Bako, Laszlo; Bhalerao, Rishikesh P

2011-02-02

305

Synchronized network activity in developing rat hippocampus involves regional hyperpolarization-activated cyclic nucleotide-gated (HCN) channel function.  

PubMed

The principal form of synchronized network activity in neonatal hippocampus consists of low frequency 'giant depolarizing potentials' (GDPs). Whereas contribution of both GABA and glutamate to their generation has been demonstrated, full understanding of the mechanisms underlying these synchronized activity bursts remains incomplete. A contribution of the h-current, conducted by HCN channels, to GDPs has been a topic of substantial interest. Here we focus on HCN1, the prevalent HCN channel isoform in neonatal hippocampus, and demonstrate an HCN1 spatiotemporal expression pattern in both CA3 principal cells and interneurons that correlates with the developmental profile of GDPs. Abrogation of HCN physiological function in CA3, via the selective I(h)-blocker ZD7288, disrupts GDP generation. Furthermore, ZD7288 specifically abolishes spontaneous bursting of the CA3 pyramidal cells at frequencies typical of GDPs without major influence on interneuronal firing. These findings support a pivotal role for HCN channels expressed by CA3 neurons, and particularly CA3 pyramidal cells, in GDP-related network synchronization. PMID:16307610

Bender, Roland A; Galindo, Rafael; Mameli, Manuel; Gonzalez-Vega, Rebeca; Valenzuela, C Fernando; Baram, Tallie Z

2005-11-01

306

Epoxyeicosatrienoic acid relaxing effects involve Ca2+-activated K+ channel activation and CPI-17 dephosphorylation in human bronchi.  

PubMed

The aim of the present study was to provide a mechanistic insight into how 14,15-epoxyeicosatrienoic acid (EET) relaxes organ-cultured human bronchi. Tension measurements, performed on either fresh or 3-d-cultured bronchi, revealed that the contractile responses to 1 microM methacholine and 10 microM arachidonic acid were largely relaxed by the eicosanoid regioisomer in a concentration-dependent manner (0.01-10 microM). Pretreatments with 14,15-epoxyeicosa-5(Z)-enoic acid, a specific 14,15-EET antagonist, prevented the relaxing effect, whereas iberitoxin pretreatments (10 nM) partially abolished EET-induced relaxations. In contrast, pretreatments with 1 microM indomethacin amplified relaxations in explants and membrane hyperpolarizations triggered by 14,15-EET on airway smooth muscle cells. The relaxing responses induced by 14,15-EET were likely related to reduced Ca2+ sensitivity of the myofilaments, because free Ca2+ concentration-response curves performed on beta-escin-permeabilized cultured explants were shifted toward higher [Ca2+] (lower pCa2+ values). 14,15-EET also abolished the tonic responses induced by phorbol-ester-dybutyrate (PDBu) (a protein kinase C [PKC]-sensitizing agent), on both fresh (intact) and beta-escin-permeabilized explants. Western blot analyses, using two specific primary antibodies against CPI-17 and its PKC-dependent phosphorylated isoform (p-CPI-17), confirmed that the eicosanoid interferes with this intracellular process. These data indicate that 14,15-EET hyperpolarizes airway smooth muscle cells and relaxes precontracted human bronchi while reducing Ca2+ sensitivity of fresh and cultured explants. The intracellular effects are related to a PKC-dependent process involving a lower phosphorylation level of CPI-17. PMID:17237191

Morin, Caroline; Sirois, Marco; Echave, Vincent; Gomes, Marcio M; Rousseau, Eric

2007-01-19

307

Calcium activates a chloride conductance likely involved in olfactory receptor neuron repolarization in the moth Spodoptera littoralis.  

PubMed

The response of insect olfactory receptor neurons (ORNs) to odorants involves the opening of Ca(2+)-permeable channels, generating an increase in intracellular Ca(2+) concentration. Here, we studied the downstream effect of this Ca(2+) rise in cultured ORNs of the moth Spodoptera littoralis. Intracellular dialysis of Ca(2+) from the patch pipette in whole-cell patch-clamp configuration activated a conductance with a K(1/2) of 2.8 microm. Intracellular and extracellular anionic and cationic substitutions demonstrated that Cl(-) carries this current. The anion permeability sequence I(-) > NO(3)(-) > Br(-) > Cl(-) > CH(3)SO(3)(-) > gluconate(-) of the Ca(2+)-activated Cl(-) channel suggests a weak electrical field pore of the channel. The Ca(2+)-activated current partly inactivated over time and did not depend on protein kinase C (PKC) and CaMKII activity or on calmodulin. Application of Cl(-) channel blockers, flufenamic acid, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or niflumic acid reversibly blocked the Ca(2+)-activated current. In addition, lowering Cl(-) concentration in the sensillar lymph bathing the ORN outer dendrites caused a significant delay in pheromone response termination in vivo. The present work identifies a new Cl(-) conductance activated by Ca(2+) in insect ORNs presumably required for ORN repolarization. PMID:20445058

Pézier, Adeline; Grauso, Marta; Acquistapace, Adrien; Monsempes, Christelle; Rospars, Jean-Pierre; Lucas, Philippe

2010-05-01

308

Genes affecting the activity of nicotinic receptors involved in Caenorhabditis elegans egg-laying behavior.  

PubMed Central

Egg-laying behavior in Caenorhabditis elegans is regulated by multiple neurotransmitters, including acetylcholine and serotonin. Agonists of nicotinic acetylcholine receptors such as nicotine and levamisole stimulate egg laying; however, the genetic and molecular basis for cholinergic neurotransmission in the egg-laying circuitry is not well understood. Here we describe the egg-laying phenotypes of eight levamisole resistance genes, which affect the activity of levamisole-sensitive nicotinic receptors in nematodes. Seven of these genes, including the nicotinic receptor subunit genes unc-29, unc-38, and lev-1, were essential for the stimulation of egg laying by levamisole, though they had only subtle effects on egg-laying behavior in the absence of drug. Thus, these genes appear to encode components of a nicotinic receptor that can promote egg laying but is not necessary for egg-laying muscle contraction. Since the levamisole-receptor mutants responded to other cholinergic drugs, other acetylcholine receptors are likely to function in parallel with the levamisole-sensitive receptors to mediate cholinergic neurotransmission in the egg-laying circuitry. In addition, since expression of functional unc-29 in muscle cells restored levamisole sensitivity under some but not all conditions, both neuronal and muscle cell UNC-29 receptors are likely to contribute to the regulation of egg-laying behavior. Mutations in one levamisole receptor gene, unc-38, also conferred both hypersensitivity and reduced peak response to serotonin; thus nicotinic receptors may play a role in regulating serotonin response pathways in the egg-laying neuromusculature.

Kim, J; Poole, D S; Waggoner, L E; Kempf, A; Ramirez, D S; Treschow, P A; Schafer, W R

2001-01-01

309

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

2012-11-15

310

A potassium ion channel is involved in cytokine production by activated human macrophages  

PubMed Central

Macrophages play an important role in immune and inflammatory responses, largely through secretion of bioactive molecule such as cytokines. While calcium is known to be an important regulator of this process, less is known about the role of other ions and the ion channels that regulate them. We have previously implicated an outwardly rectifying potassium channel (Kor) in this process and for this reason we have investigated the role of potassium (K+) and K+ channels in the regulation of tumour necrosis factor-? (TNF-?)and interleukin (IL)-8 production by activated human culture-derived macrophages. The effect of blockade of Kor is to inhibit phorbol myristate acetate (PMA)-induced cytokine production by translational or post-translational mechanisms, an effect that is duplicated by increasing extracellular K+. By contrast, the effects of K+ on LPS-stimulated cells are far more complex and are probably mediated through the change of osmolality and occur largely at the mRNA level. This data directly implicates K+, and its regulation through Kor, in early events following PMA stimulation of these cells.

QIU, M R; CAMPBELL, T J; BREIT, S N

2002-01-01

311

Growth hormone activity in mitochondria depends on GH receptor Box 1 and involves caveolar pathway targeting  

SciTech Connect

Growth hormone (GH) binding to its receptor (GHR) initiates GH-dependent signal transduction and internalization pathways to generate the biological effects. The precise role and way of action of GH on mitochondrial function are not yet fully understood. We show here that GH can stimulate cellular oxygen consumption in CHO cells transfected with cDNA coding for the full-length GHR. By using different GHR cDNA constructs, we succeeded in determining the different parts of the GHR implicated in the mitochondrial response to GH. Polarography and two-photon excitation fluorescence microscopy analysis showed that the Box 1 of the GHR intracellular domain was required for an activation of the mitochondrial respiration in response to a GH exposure. However, confocal laser scanning microscopy demonstrated that cells lacking the GHR Box 1 could efficiently internalize the hormone. We demonstrated that internalization mediated either by clathrin-coated pits or by caveolae was able to regulate GH mitochondrial effect: these two pathways are both essential to obtain the GH stimulatory action on mitochondrial function. Moreover, electron microscopic and biochemical approaches allowed us to identify the caveolar pathway as essential for targeting GH and GHR to mitochondria.

Perret-Vivancos, Cecile [CNRS UMR 5123, Bat. R. Dubois, Universite Claude Bernard-Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex (France); Abbate, Aude [CNRS UMR 5123, Bat. R. Dubois, Universite Claude Bernard-Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex (France); Ardail, Dominique [INSERM U189-Faculte de medecine Lyon Sud, 69921 Oullins cedex (France); Raccurt, Mireille [CNRS UMR 5123, Bat. R. Dubois, Universite Claude Bernard-Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex (France); Usson, Yves [UMR 5525 CNRS, Institut de l'Ingenierie de l'Information de Sante (IN3S) Domaine de la Merci, Universite Joseph Fourier, 38706 La Tronche cedex (France); Lobie, Peter E. [Liggins Institute, University of Aukland, 2-6 Park Avenue, Private Bag, Aukland 92019 (New Zealand); Morel, Gerard [CNRS UMR 5123, Bat. R. Dubois, Universite Claude Bernard-Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex (France)]. E-mail: gerard.morel@univ-lyon1.fr

2006-02-01

312

Predictors of condom use among sexually active persons involved in compulsory national service in Ibadan, Nigeria.  

PubMed

Migration is known to increase the risk of heterosexual transmission of human immunodeficiency virus (HIV) in sub-Saharan Africa, but little attention has been paid to fresh graduates of tertiary institutions who are on migration for compulsory national assignment in Nigeria. In July and August 2004, a survey was conducted on sexually active men (n = 344) and women (n = 373) to investigate determinants of condom use during national service. Sixty-eight percent of men and 41% of women reported condom use at last intercourse before the survey. For both men and women, condom use was common if they had one or more regular sex partners and if they were purchasing condoms. In addition, women's condom use was predicted by being single and having intention to use condoms in next intercourse. The findings further showed that there was high risk of HIV transmission in the sample population as consistent condom use was 15% for men and 4% for women. Twelve percent of men and 8% of women reported STI diagnoses in the last 12 months before the survey. Four percent of men and 2% of women reported they already had HIV diagnoses. Only 1% of men and 2% of women reported they would receive voluntary HIV test if offered free by the government. The study findings suggest the need to extend the existing condom social marketing services in the country to the youth on national service and promote condom education messages among them prior to commencing national service. PMID:16997898

Sunmola, Adegbenga M; Olley, Benjamin O; Oso, Grace E

2006-09-22

313

Involvement of Acinetobacter sp. in the floc-formation in activated sludge process.  

PubMed

The coaggregation behavior of Acinetobacter johnsonii S35 isolate with sewage bacteria was assessed by a spectrophotometric assay using different samples from a municipal wastewater treatment plant and a community plant. A. johnsonii S35 coaggregated well with other free bacteria and microflocs at the mixing ratios of 0.2:1-0.6:1 of A. johnsonii S35 and sewage samples. In addition, the size of coaggregates became larger (100 ?m or more) under the same conditions. A. johnsonii S35 cells were highly adsorbed (adsorption=93-99%) onto sludge samples. Microbial adhesion to hydrocarbon (MATH) test and adsorption to octyl-Sepharose CL-4B showed that A. johnsonii S35 cells and sludge samples had a hydrophobic character. The population of Acinetobacter spp. in sewage treatment plants was 2-7% and its role in bioflocculation was discussed. The present study revealed that A. johnsonii S35 isolate can play as a bridging organism and contribute in floc-formation in activated sludge process. PMID:22001846

Phuong, Kimchhayarasy; Hanazaki, Shohei; Kakii, Kazuo; Nikata, Toshiyuki

2011-10-02

314

Calmodulin Involvement in Stress-Activated Nuclear Localization of Albumin in JB6 Epithelial Cells.  

SciTech Connect

We report that in response to oxidative stress, albumin is translocated to the nucleus where it binds in concert with known transcription factors to an antioxidant response element (ARE), which controls the expression of glutathione-S-transferase and other antioxidant enzymes, functioning to mediate adaptive cellular responses. To investigate the mechanisms underlying this adaptive cell response, we have identified linkages between calcium signaling and the nuclear translocation of albumin in JB6 epithelial cells. Under resting conditions, albumin and the calcium regulatory protein, calmodulin (CaM), co-immunoprecipitate using antibodies against either protein, indicating a tight association. Calcium activation of CaM disrupts the association between CaM and albumin, suggesting that transient increases in cytosolic calcium levels function to mobilize intracellular albumin to facilitate its translocation into the nucleus. Likewise, nuclear translocation of albumin is induced by exposure of cells to hydrogen peroxide or a phorbol ester, indicating a functional linkage between reactive oxygen species, calcium, and PKC-signaling pathways. Inclusion of an antioxidant enzyme (i.e., superoxide dismutase) blocks nuclear translocation, suggesting that the oxidation of sensitive proteins functions to coordinate the adaptive cellular response. These results suggest that elevated calcium transients, and associated increases in reactive oxygen species, contribute to adaptive cellular responses through the mobilization and nuclear translocation of cellular albumin to mediate the transcriptional regulation of antioxidant responsive elements.

Weber, Thomas J.; Negash, Sewite; Smallwood, Heather S.; Ramos, Kenneth S.; Thrall, Brian D.; Squier, Thomas C.

2004-06-15

315

IL-33 accelerates cutaneous wound healing involved in upregulation of alternatively activated macrophages.  

PubMed

IL-33 is a recently recognized member of the IL-1 family and has been best identified as a potent inducer of Th2-type immune responses. Increasing evidence, however, indicates that IL-33 also represents an important mediator of mucosal healing and epithelial restoration and repair. In this study, we further explore the potential effect of IL-33 in cutaneous wound healing. A full-thickness skin wound was generated on the back of mice and treated with IL-33 or vehicle intraperitoneally. Our results revealed that the levels of IL-33 mRNA and protein were significantly enhanced in incisional wound skin. Meantime, administration of IL-33 obviously accelerated wound healing with wounds gaping narrower and exhibiting enhanced reepithelialization. IL-33 upregulation also promoted the collagen deposition and the expression of extracellular matrix (ECM)-associated genes such as fibronectin and collagen IIIa, which implies a direct effect of IL-33 on matrix synthesis. Furthermore, IL-33 facilitated the development of alternatively activated macrophages (AAM) in incisional wound tissue, which closely related to resolution of inflammation and promotion of wound repair. Taken together, these findings suggest that IL-33 may play a pivotal role in maintenance of cutaneous homeostasis and acceleration of normal wound healing. PMID:23911389

Yin, Hui; Li, Xiangyong; Hu, Shilian; Liu, Tao; Yuan, Baohong; Gu, Hongbiao; Ni, Qian; Zhang, Xiaofan; Zheng, Fang

2013-08-01

316

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

317

The Beyond Einstein Explorers' Program (BEEP) Getting Astronomers Involved in Afterschool Activities  

NASA Astrophysics Data System (ADS)

There is tremendous potential for astronomers to engage afterschool programs in their local areas. Afterschool programs reach a diverse population of students and allow for learning experiences different from those in a classroom. We offer an astronomy afterschool program that scientists can easily adopt, adapt, and run in their local areas. BEEP is targeted at middle school students and introduces basic astronomical tools and the Universe beyond the solar system. The primary goal of the program is to spark curiosity and excitement about the Universe in both program leaders (who often don’t have a science background) and students. A promising model for training leaders and maintaining oversight of the programs is to have a team consisting of a scientist and 1-2 astronomy graduate students partnering with local afterschool program(s). BEEP’s structure is flexible enough to be split into modules and run in a variety of settings, from “astronomy days” to summer camps to year-long afterschool programming. We also welcome the opportunity to work with astronomers running this program to add new modules. This program was developed in close collaboration with afterschool programs in the Washington, DC area. The sessions were developed by adapting well-tested existing formal education materials and activities for the afterschool environment. The program was piloted in summer 2006 and evaluations showed that it was successful and met our primary goal of engaging the students (and preparing the leaders). We are currently refining this program to reflect feedback from the pilot, and it will be ready for wider dissemination by summer 2007.

Krishnamurthi, Anita; Barbier, B.; Mitchell, S.; Lochner, J.

2006-12-01

318

The involvement of iNOS activity in the anticonvulsant effect of grape seed extract on the penicillin-induced epileptiform activity in rats.  

PubMed

Grape seed extract (GSE) has been known as being neuroprotective due to its antioxidant properties. The aim of the present study was to examine both the effect of GSE on the penicillin-induced epileptiform activity in rat and the role of nitric oxide (NO) pathway in the effect of GSE. GSE, at doses of 50, 100, 200 mg/kg, significantly decreased the mean frequency of epileptiform activity. GSE, at the highest dose (400 mg/kg), did not change either the frequency or amplitude of epileptiform activity. GSE, at a dose of 200 mg/kg, was the most effective in changing the frequency of epileptiform activity. The occurrence of anticonvulsant activity of GSE was significantly delayed in the presence of selective inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (60 mg/kg), which was inhibited by the NO precursor, L-arginine (500 mg/kg). The administration of a non-selective NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) partially reversed the anticonvulsant activity of GSE. Selective neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole (7-NI) and L-arginine showed a similar anticonvulsant activity in the presence of GSE. The electrophysiological evidence of the present study indicates that GSE decreases the mean frequency of penicillin-induced epileptiform activity, suggesting an anticonvulsant role. iNOS/NO pathway could be involved in mediating anticonvulsant effect of GSE on the epileptiform activity. PMID:23524183

Per, S; Tasdemir, A; Yildirim, M; Ayyildiz, M; Ayyildiz, N; Agar, Erdal

2013-06-01

319

Public involvement in the priority setting activities of a wait time management initiative: a qualitative case study  

PubMed Central

Background As no health system can afford to provide all possible services and treatments for the people it serves, each system must set priorities. Priority setting decision makers are increasingly involving the public in policy making. This study focuses on public engagement in a key priority setting context that plagues every health system around the world: wait list management. The purpose of this study is to describe and evaluate priority setting for the Ontario Wait Time Strategy, with special attention to public engagement. Methods This study was conducted at the Ontario Wait Time Strategy in Ontario, Canada which is part of a Federal-Territorial-Provincial initiative to improve access and reduce wait times in five areas: cancer, cardiac, sight restoration, joint replacements, and diagnostic imaging. There were two sources of data: (1) over 25 documents (e.g. strategic planning reports, public updates), and (2) 28 one-on-one interviews with informants (e.g. OWTS participants, MOHLTC representatives, clinicians, patient advocates). Analysis used a modified thematic technique in three phases: open coding, axial coding, and evaluation. Results The Ontario Wait Time Strategy partially meets the four conditions of 'accountability for reasonableness'. The public was not directly involved in the priority setting activities of the Ontario Wait Time Strategy. Study participants identified both benefits (supporting the initiative, experts of the lived experience, a publicly funded system and sustainability of the healthcare system) and concerns (personal biases, lack of interest to be involved, time constraints, and level of technicality) for public involvement in the Ontario Wait Time Strategy. Additionally, the participants identified concern for the consequences (sustainability, cannibalism, and a class system) resulting from the Ontario Wait Times Strategy. Conclusion We described and evaluated a wait time management initiative (the Ontario Wait Time Strategy) with special attention to public engagement, and provided a concrete plan to operationalize a strategy for improving public involvement in this, and other, wait time initiatives.

Bruni, Rebecca A; Laupacis, Andreas; Levinson, Wendy; Martin, Douglas K

2007-01-01

320

Immune complexes activate human endothelium involving the cell-signaling HMGB1-RAGE axis in the pathogenesis of lupus vasculitis.  

PubMed

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the formation of immune complexes (ICs), which contain a complex mixture of autoantigens nucleic acids, nucleic acids-associated proteins and corresponding autoantibodies. In SLE, ICs are deposited in multiple organs. Vasculopathy and vasculitis in SLE are typical complications and are associated with deposition of ICs on endothelium, endothelial activation and inflammatory cell infiltration. However, the effects of ICs on endothelial cells and the mechanisms involved remain unclear. In this study, we have demonstrated for the first time that ICs upregulated cell surface expression of the receptor for advanced glycation end products (RAGE), the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), increased the secretion of the chemokines interleukin 8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), the proinflammatoy cytokines interleukin 6 (IL-6), tumor necrosis factor-? (TNF-?) and promoted the activation of the transcription factor NF-?B p65 in human endothelial cells (P<0.05). ICs also increased transendothelial migration of monocytes (P<0.05). One of the mechanisms underlying these activating effects of ICs on human endothelial cells involves cell signaling by high-mobility group box 1 protein (HMGB1)-RAGE axis, as these effects can be partially blocked by HMGB1 A-box, soluble RAGE (sRAGE), SB203580, PD98059, Bay 117082 (P<0.05) and co-treatment with these agents (P<0.05). In conclusion, ICs elicit proinflammatory responses in human endothelial cells and alter their function involving cellular signaling via the HMGB1-RAGE axis in the pathogenesis of SLE vasculitis. PMID:23628898

Sun, Wenping; Jiao, Yulian; Cui, Bin; Gao, Xuejun; Xia, Yu; Zhao, Yueran

2013-04-29

321

Thioredoxin Is Involved in Endothelial Cell Extracellular Transglutaminase 2 Activation Mediated by Celiac Disease Patient IgA  

PubMed Central

Purpose To investigate the role of thioredoxin (TRX), a novel regulator of extracellular transglutaminase 2 (TG2), in celiac patients IgA (CD IgA) mediated TG2 enzymatic activation. Methods TG2 enzymatic activity was evaluated in endothelial cells (HUVECs) under different experimental conditions by ELISA and Western blotting. Extracellular TG2 expression was studied by ELISA and immunofluorescence. TRX was analysed by Western blotting and ELISA. Serum immunoglobulins class A from healthy subjects (H IgA) were used as controls. Extracellular TG2 enzymatic activity was inhibited by R281. PX12, a TRX inhibitor, was also employed in the present study. Results We have found that in HUVECs CD IgA is able to induce the activation of extracellular TG2 in a dose-dependent manner. Particularly, we noted that the extracellular modulation of TG2 activity mediated by CD IgA occurred only under reducing conditions, also needed to maintain antibody binding. Furthermore, CD IgA-treated HUVECs were characterized by a slightly augmented TG2 surface expression which was independent from extracellular TG2 activation. We also observed that HUVECs cultured in the presence of CD IgA evinced decreased TRX surface expression, coupled with increased secretion of the protein into the culture medium. Intriguingly, inhibition of TRX after CD IgA treatment was able to overcome most of the CD IgA-mediated effects including the TG2 extracellular transamidase activity. Conclusions Altogether our findings suggest that in endothelial cells CD IgA mediate the constitutive activation of extracellular TG2 by a mechanism involving the redox sensor protein TRX.

Antonella Nadalutti, Cristina; Korponay-Szabo, Ilma Rita; Kaukinen, Katri; Wang, Zhuo; Griffin, Martin; Maki, Markku; Lindfors, Katri

2013-01-01

322

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

323

Purine nucleoside-mediated protection of chemical hypoxia-induced neuronal injuries involves p42/44 MAPK activation.  

PubMed

Hypoxia in brain may lead to cell death by apoptosis and necrosis. Concomitant is the formation of purine nucleosides, e.g. adenosine, a powerful endogenous neuroprotectant. Despite vigorous studies, many aspects of the mechanisms involved in purine-based protection are still unclear. In this study, we wanted to investigate the effect of purine nucleosides on cellular responses to chemical hypoxia. O(2)-sensitive neuronal pheochromocytoma (PC12)-cells, which are widely used as a model system for sympathetic ganglion-like neurons, were subjected to chemical hypoxia induced with rotenone, an inhibitor of mitochondrial complex I. Adenosine and its relatives guanosine and inosine were tested for their neuroprotective capability to improve neurite outgrowth and viability. In addition, cell lysates were analyzed for mitogen-activated-protein-kinases (MAPK) activation by anti-active and anti-total MAPKinase immunoblotting. Adenosine, guanosine and inosine significantly inhibited the loss of viability after hypoxic insult. In combination with NGF, purine nucleosides also partially rescued neurite outgrowth. The MEK-1/-2 inhibitor PD098059 inhibited purine nucleoside-mediated protection up to 85.23% and also markedly decreased neurite formation induced by NGF and purine nucleosides in hypoxic cells. Immunoblot analysis revealed a strong activation of MAPKinase upon incubation of cells with adenosine, guanosine or inosine. In combination with NGF an additive effect was observed. Results suggested that activation of the MAPKinase pathway plays a vital role in purine nucleoside-mediated protection of neuronal cells following hypoxic insult. PMID:15843045

Tomaselli, Bettina; Podhraski, Valerie; Heftberger, Veronika; Böck, Günther; Baier-Bitterlich, Gabriele

2005-06-01

324

Morphine stimulates locomotor activity by an indirect dopaminergic mechanism: possible D-1 and D-2 receptor involvement.  

PubMed

1. The effect of morphine on locomotor activity in mice and the mechanism involved were evaluated. 2. Subcutaneous (s.c.) injection of different doses of morphine (10, 20 and 40 mg kg-1) into mice induced a dose-dependent locomotor activity. 3. The response to morphine was decreased in animals pretreated by the D-1 antagonist SCH 23390, the D-2 antagonist sulpiride or the opiate receptor antagonist naloxone, but not by atropine, phenoxybenzamine, propranolol and methergoline. 4. The inhibitory effects of SCH 23390, sulpiride or naloxone were dose-dependent. 5. Pretreatment with reserpine prevented the effect of morphine. SKF 38393 (D-1 agonist) or quinpirole (D-2 agonist) also induced locomotor activity in mice. Also this effect was decreased by reserpine pretreatment. 6. Combination of SKF 38393 with quinpirole but not of morphine with SKF 38393 or quinpirole induced a high degree of locomotor activity in intact and reserpinized animals. 7. It is concluded that locomotor activity induced by morphine is mediated by opiate receptor through an indirect dopaminergic mechanism. PMID:1362552

Zarrindast, M R; Zarghi, A

1992-11-01

325

Nonribosomal biosynthesis of fusaricidins by Paenibacillus polymyxa PKB1 involves direct activation of a D-amino acid.  

PubMed

Paenibacillus polymyxa PKB1 produces fusaricidins, a family of lipopeptide antibiotics that strongly inhibits the growth of many plant pathogenic fungi. The fusaricidin biosynthetic gene cluster was cloned and sequenced, and it spans 32.4 kb, including an open reading frame (fusA) encoding a six-module nonribosomal peptide synthetase. The second, fourth, and fifth modules of fusaricidin synthetase each contain an epimerization domain, consistent with the structure of fusaricidins. However, no epimerization domain is found in the sixth module, corresponding to D-Ala. This sixth adenylation domain was produced at a high level in Escherichia coli and is shown to activate D-Ala specifically, providing evidence for direct activation of a D-amino acid by a prokaryotic peptide synthetase. The fusaricidin gene cluster also includes genes involved in the biosynthesis of the lipid moiety, but no genes for resistance, regulation, or transport functions were encountered. PMID:18291316

Li, Jingru; Jensen, Susan E

2008-02-01

326

Reduction of scale invariance of activity fluctuations with aging and Alzheimer's disease: Involvement of the circadian pacemaker  

PubMed Central

Human motor control systems orchestrate complex scale-invariant patterns of activity over a wide range of time scales (minutes to hours). The neural mechanisms underlying scale-invariance are unknown in humans. In rats, the master circadian pacemaker [suprachiasmatic nucleus (SCN)] is crucially involved in scale-invariant activity fluctuations over multiple time scales from minutes to 24 h. Aging and Alzheimer's disease (AD) are associated with progressive dysfunction of the SCN. Thus, if the SCN is responsible for the scale-invariant activity fluctuations in humans, we predict disturbances of scale-invariant activity fluctuations in elderly humans and even more pronounced disturbances in elderly humans with AD. To test these hypotheses, we studied spontaneous daytime activity patterns in 13 young adults (mean ± SD: 25.5 ± 6.1 y); 13 elderly people with early-stage AD (68.5 ± 6.1 y) matched with 13 elderly controls (68.6 ± 6.1 y); and 14 very old people with late-stage AD (83.9 ± 6.7 y) matched with 12 very old controls (80.8 ± 8.6 y). In young adults, activity exhibited robust scale-invariant correlations across all tested time scales (minutes to 8 h). The scale-invariant correlations at 1.5–8 h declined with age (P = 0.01) and were significantly reduced in the elderly (P = 0.04) and very old controls (P = 0.02). Remarkably, an age-independent AD effect further reduced the scale-invariant correlations at 1.5–8 h (P = 0.04), leading to the greatest reduction of the scale-invariant correlations in very old people with late-stage AD—resembling closely the loss of correlations at large time scales in SCN-lesioned animals. Thus, aging and AD significantly attenuate the scale invariance of activity fluctuations over multiple time scales. This attenuation may reflect functional changes of the SCN.

Hu, Kun; Van Someren, Eus J. W.; Shea, Steven A.; Scheer, Frank A. J. L.

2009-01-01

327

AMP-ACTIVATED PROTEIN KINASE IS INVOLVED IN HORMONE-INDUCED MOUSE OOCYTE MEIOTIC MATURATION IN VITRO  

PubMed Central

We have previously shown that AMP-activated protein kinase (AMPK) can induce the resumption of meiosis in mouse oocytes maintained in meiotic arrest in vitro. The present study was carried out to determine whether AMPK activation is involved in hormone-induced maturation. Follicle-stimulating hormone (FSH) and the EGF-like peptide, amphiregulin (AR), are potent inducers of maturation in cumulus cell-enclosed oocytes (CEO). Within 3 h of FSH treatment, phosphoacetyl CoA carboxylase (ACC) levels were increased in germinal vesicle (GV)-stage oocytes when compared to non-stimulated controls and remained elevated throughout 9 h of culture, indicating AMPK activation. A similar response to AR was observed after 6 h of culture. Using PT172 antibody (binds only to activated AMPK), Western analysis demonstrated active AMPK in both FSH- or AR-treated GV-stage oocytes within 6 h. The AMPK inhibitors, compound C and adenine 9-beta-D-arabinofuranoside (araA), blocked FSH- or AR-induced meiotic resumption and ACC phosphorylation, further supporting a causal role for AMPK in hormone-induced meiotic resumption. Immunocytochemistry using anti-PT172-AMPK antibody showed an increased diffuse cytoplasmic staining and more intense punctate staining in the germinal vesicles of oocytes following treatment with the AMPK activator, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), or with FSH or AR, and this staining was eliminated by compound C or a blocking peptide for the anti-PT172 antibody. Staining of oocytes from hCG-stimulated mice with the anti-PT172 antibody also showed pronounced label in the germinal vesicles within 1-2 h. Further, in oocytes from all groups, active AMPK was always observed in association with the condensed chromosomes of maturing oocytes. Taken together, these results support a role for AMPK in FSH and AR-induced maturation in vitro and hCG-induced maturation in vivo.

Chen, Jing; Downs, Stephen M.

2009-01-01

328

Oxygen-glucose deprivation promotes gliogenesis and microglia activation in organotypic hippocampal slice culture: involvement of metalloproteinases.  

PubMed

Organotypic hippocampal cultures are used as an alternative model for studying molecular mechanism(s) of neurogenesis after combined oxygen-glucose deprivation (OGD) mimicking ischemic conditions. The aim of the present work was to investigate the effect of OGD on stem/progenitor cells proliferation and/or differentiation in the hippocampus. Our attention was primarily focused on the relationship between neurogenesis-associated processes and activity of matrix metalloproteinases (MMPs). Cell proliferation was detected by using BrdU incorporation. Newly generated BrdU (+) cells were identified by labeling with specific cell markers. In order to check the activity and localization of MMPs we conducted in situ zymography in conjunction with immunohistochemistry. In our experimental conditions OGD-insult followed by 24 h of recovery caused the damage of neuronal cells in CA1. At 1 week cell death appears all over the hippocampus. We found that expected stimulation of endogenous neurogenesis fails as a source of compensation for the lost neurons in OGD-treated cultures. The modulation of culture microenvironment after ischemia favors the dominant proliferation of glial cells expressed by the enhancement of newly-generated oligodendrocyte progenitors. In addition, during our study we also detected some BrdU labeled nuclei encapsulated by GFAP positive processes. However, the majority of BrdU positive cells expressed microglial specific stain, particularly pronounced in CA1area. The OGD-promoted responses involved activation of metalloproteinases, which matches the progression of gliogenesis. On the other hand, the high activity of MMPs associated with microglial cells implicate their involvement in the mechanism participating in OGD-induced cell damage. PMID:23595289

Ziemka-Na??cz, Ma?gorzata; Stanaszek, Luiza; Zalewska, Teresa

2013-01-01

329

Involvement of Vacuolar Sequestration and Active Transport in Tolerance of Saccharomyces cerevisiae to Hop Iso-?-Acids? † ¶  

PubMed Central

The hop plant, Humulus lupulus L., has an exceptionally high content of secondary metabolites, the hop ?-acids, which possess a range of beneficial properties, including antiseptic action. Studies performed on the mode of action of hop iso-?-acids have hitherto been restricted to lactic acid bacteria. The present study investigated molecular mechanisms of hop iso-?-acid resistance in the model eukaryote Saccharomyces cerevisiae. Growth inhibition occurred at concentrations of hop iso-?-acids that were an order of magnitude higher than those found with hop-tolerant prokaryotes. Chemostat-based transcriptome analysis and phenotype screening of the S. cerevisiae haploid gene deletion collection were used as complementary methods to screen for genes involved in hop iso-?-acid detoxification and tolerance. This screening and further analysis of deletion mutants confirmed that yeast tolerance to hop iso-?-acids involves three major processes, active proton pumping into the vacuole by the vacuolar-type ATPase to enable vacuolar sequestration of iso-?-acids and alteration of cell wall structure and, to a lesser extent, active export of iso-?-acids across the plasma membrane. Furthermore, iso-?-acids were shown to affect cellular metal homeostasis by acting as strong zinc and iron chelators.

Hazelwood, Lucie A.; Walsh, Michael C.; Pronk, Jack T.; Daran, Jean-Marc

2010-01-01

330

Genes involved in protein glycosylation determine the activity and cell internalization of the antifungal peptide PAF26 in Saccharomyces cerevisiae.  

PubMed

We have previously characterized the synthetic hexapeptide PAF26 as a cell-penetrating and non-lytic antifungal peptide that is active against Saccharomyces cerevisiae and filamentous fungi. Numerous cell wall (CW) proteins are glycosylated in fungi and many of these play important roles in fungal pathogenesis. In this study, we screened a collection of S. cerevisiae deletion mutants for protein glycosylation genes whose deletion altered the sensitivity to PAF26. Increased tolerance to PAF26 was observed in mutants with the following disrupted genes: PMT1-6, EOS1, ALG5, MNN1, MNN4 and MNN5. Significantly, genes coding for protein O-mannosyltransferase 2 (Pmt2p), which is responsible for the addition of the first mannosyl residue of O-linked carbohydrates, and for Eos1p, an enzyme involved in N-linked glycosylation of proteins, showed resistance to PAF26 and defects in CW integrity. Microscopic studies on the S. cerevisiae ?eos1 deletion mutant demonstrated a blockage of peptide internalization by cells. Protoplasts lacking CWs interacted with the peptide, but were more resistant to peptide killing than cells possessing CWs due to a blockage in PAF26 internalization. Interestingly, protoplasts obtained from ?eos1 behaved similarly to those of the parental strain. Collectively, these observations demonstrate that the CW is a positive factor that determines the internalization of the PAF26, and that Eos1p exerts its activity through the glycosylation of specific protein(s) involved in peptide internalization. PMID:23942187

Harries, Eleonora; Carmona, Lourdes; Muńoz, Alberto; Ibeas, José I; Read, Nick D; Gandía, Mónica; Marcos, Jose F

2013-08-11

331

Direct downstream targets of proneural activators in the imaginal disc include genes involved in lateral inhibitory signaling.  

PubMed

In Drosophila imaginal discs, the spatially restricted activities of the achaete (ac) and scute (sc) proteins, which are transcriptional activators of the basic-helix-loop-helix class, define proneural clusters (PNCs) of potential sensory organ precursor (SOP) cells. Here, we report the identification of several genes that are direct downstream targets of ac-sc activation, as judged by the following criteria. The genes are expressed in the PNCs of the wing imaginal disc in an ac-sc-dependent manner; the proximal promoter regions of all of these genes contain one or two high-affinity ac-sc binding sites, which define the novel consensus GCAGGTG(T/G)NNNYY; where tested, these binding sites are required in vivo for PNC expression of promoter-reporter fusion genes. Interestingly, these ac-sc target genes, including Bearded, Enhancer of split m7, Enhancer of split m8, and scabrous, are all known or believed to function in the selection of a single SOP from each PNC, a process mediated by inhibitory cell-cell interactions. Thus, one of the earliest steps in adult peripheral neurogenesis is the direct activation by proneural proteins of genes involved in restricting the expression of the SOP cell fate. PMID:7958878

Singson, A; Leviten, M W; Bang, A G; Hua, X H; Posakony, J W

1994-09-01

332

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

333

Mannan-binding lectin activates C3 and the alternative complement pathway without involvement of C2  

PubMed Central

Lectin pathway activation of C3 is known to involve target recognition by mannan-binding lectin (MBL) or ficolins and generation of classical pathway C3 convertase via cleavage of C4 and C2 by MBL-associated serine protease 2 (MASP-2). We investigated C3 activation in C2-deficient human sera and in sera with other defined defects of complement to assess other mechanisms through which MBL might recruit complement. The capacity of serum to support C3 deposition was examined by ELISA using microtiter plates coated with O antigen–specific oligosaccharides derived from Salmonella typhimurium, S. thompson, and S. enteritidis corresponding to serogroups B, C, and D (BO, CO, and DO). MBL bound to CO, but not to BO and DO, and efficiently supported C3 deposition in the absence of C2, C4, or MASP-2. The existence of an MBL-dependent C2 bypass mechanism for alternative pathway–mediated C3 activation was clearly demonstrated using CO, solid-phase mannan, and E. coli LPS. MASP-1 might contribute, but was not required for C3 deposition in the model used. Independent of MBL, specific antibodies to CO supported C3 deposition through classical and alternative pathways. MBL-dependent C2 bypass activation could be particularly important in various inherited and acquired complement deficiency states.

Selander, Barbro; Martensson, Ulla; Weintraub, Andrej; Holmstrom, Eva; Matsushita, Misao; Thiel, Steffen; Jensenius, Jens C.; Truedsson, Lennart; Sjoholm, Anders G.

2006-01-01

334

Structures of Rhodopsin Kinase in Different Ligand States Reveal Key Elements Involved in G Protein-coupled Receptor Kinase Activation  

SciTech Connect

G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate activated heptahelical receptors, leading to their uncoupling from G proteins. Here we report six crystal structures of rhodopsin kinase (GRK1), revealing not only three distinct nucleotide-binding states of a GRK but also two key structural elements believed to be involved in the recognition of activated GPCRs. The first is the C-terminal extension of the kinase domain, which was observed in all nucleotide-bound GRK1 structures. The second is residues 5-30 of the N terminus, observed in one of the GRK1{center_dot}(Mg{sup 2+}){sub 2} {center_dot}ATP structures. The N terminus was also clearly phosphorylated, leading to the identification of two novel phosphorylation sites by mass spectral analysis. Co-localization of the N terminus and the C-terminal extension near the hinge of the kinase domain suggests that activated GPCRs stimulate kinase activity by binding to this region to facilitate full closure of the kinase domain.

Singh, Puja; Wang, Benlian; Maeda, Tadao; Palczewski, Krzysztof; Tesmer, John J.G. (Case Western); (Michigan)

2008-10-08

335

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

336

Potential of laticifer fluids for inhibiting Aedes aegypti larval development: evidence for the involvement of proteolytic activity.  

PubMed

It has been shown previously that the laticifer fluid of Calotropis procera (Ait.) R.Br. is highly toxic to the egg hatching and larval development of Aedes aegypti L. In the present study, the larvicidal potential of other laticifer fluids obtained from Cryptostegia grandiflora R.Br., Plumeria rubra L. and Euphorbia tirucalli L. was evaluated. We attempted to correlate larvicidal activity with the presence of endogenous proteolytic activity in the protein fraction of the fluids. After collection, the fluids were processed by centrifugation and dialysis to obtain the soluble laticifer protein (LP) fractions and eliminate water insoluble and low molecular mass molecules. LP did not visibly affect egg hatching at the doses assayed. LP from Cr. grandiflora exhibited the highest larval toxicity, while P. rubra was almost inactive. E. tirucalli was slightly active, but its activity could not be correlated to proteins since no protein was detected in the fluid. The larvicidal effects of LP from C. procera and Cr. grandiflora showed a significant relationship with the proteolytic activity of cysteine proteinases, which are present in both materials. A purified cysteine proteinase (papain) from the latex of Carica papaya (obtained from Sigma) was similarly effective, whereas trypsin and chymotrypsin (both serine proteinases) were ineffective. The results provide evidence for the involvement of cysteine proteinase activity in the larvicidal action of some laticifer fluids. C. procera is an invasive species found in areas infested with Ae. aegypti and thus could prove useful for combating mosquito proliferation. This is the first report to present evidence for the use of proteolytic enzymes as chemical agents to destroy Ae. aegypti larvae. PMID:19876551

Ramos, Márcio V; Pereira, Danielle A; Souza, Diego P; Araújo, Eliane S; Freitas, Cléverson Dt; Cavalheiro, Mariana G; Matos, Mayara Patricia V; Carvalho, Ana Fu

2009-09-01

337

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

2013-07-18

338

Involvement of Prolonged Ras Activation in Thrombopoietin-Induced Megakaryocytic Differentiation of a Human Factor-Dependent Hematopoietic Cell Line  

PubMed Central

Thrombopoietin (TPO) is a hematopoietic growth factor that plays fundamental roles is both megakaryopoiesis and thrombopoiesis through binding to its receptor, c-mpl. Although TPO has been shown to activate various types of intracellular signaling molecules, such as the Janus family of protein tyrosine kinases, signal transducers and activators of transcription (STATs), and ras, the precise mechanisms underlying TPO-induced proliferation and differentiation remain unknown. In an effort to clarify the mechanisms of TPO-induced proliferation and differentiation, c-mpl was introduced into F-36P, a human interleukin-3 (IL-3)-dependent erythroleukemia cell line, and the effects of TPO on the c-mpl-transfected F-36P (F-36P-mpl) cells were investigated. F-36P-mpl cells were found to proliferate and differentiate at a high rate into mature megakaryocytes in response to TPO. Dominant-negative (dn) forms of STAT1, STAT3, STAT5, and ras were inducibly expressed in F-36P-mpl cells, and their effects on TPO-induced proliferation and megakaryocytic differentiation were analyzed. Among these dn molecules, both dn ras and dn STAT5 reduced TPO- or IL-3-induced proliferation of F-36P-mpl cells by ?30%, and only dn ras could inhibit TPO-induced megakaryocytic differentiation. In accord with this result, overexpression of activated ras (H-rasG12V) for 5 days led to megakaryocytic differentiation of F-36P-mpl cells. In a time course analysis on H-rasG12V-induced differentiation, activation of the ras pathway for 24 to 28 h was required and sufficient to induce megakaryocytic differentiation. Consistent with this result, the treatment of F-36P-mpl cells with TPO was able to induce prolonged activation of ras for more than 24 h, whereas IL-3 had only a transient effect. These results suggest that prolonged ras activation may be involved in TPO-induced megakaryocytic differentiation.

Matsumura, Itaru; Nakajima, Koichi; Wakao, Hiroshi; Hattori, Seisuke; Hashimoto, Koji; Sugahara, Hiroyuki; Kato, Takashi; Miyazaki, Hiroshi; Hirano, Toshio; Kanakura, Yuzuru

1998-01-01

339

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

340

Glycogen content and activities of enzymes involved in the carbohydrate metabolism of the salivary glands of rats during postnatal development.  

PubMed

Carbohydrate metabolism was examined in the developing rat salivary glands by analysing enzymatic activity and glycogen content in the postnatal parotid and submandibular glands. The following enzymes of the carbohydrate metabolism, hexokinase (HK), phosphofructokinase-1 (PFK-1), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G6PD), and lactate dehydrogenase (LDH) as well as the content of glycogen were determined in the salivary glands of rats aged 2, 7, 14, 21, 30 and 60 days. The specific activity of HK increased from days 2 to 21 and then it decreased up to 60 days old. The values found for the submandibular glands were from 2.5 to 4.9 times higher than those found for the parotid gland, except for rats aged 60 days. PFK-1 showed a different pattern of variation between the glands. In the submandibular gland there was a statistically significant increase in PFK-1 specific activity from 2 to 30 days of age and then, in the 60 days old group a return to level of the rats aged 2 days. In parotid gland, the specific activity of PFK-1 decreased between 2 and 7 days of age, from 7 to 14 days the specific activity increased markedly and from 14 to 60 days old it gradually decreased. The specific activity of PK followed the same pattern of variation in the submandibular and parotid glands, showing no great variation. The specific activity of LDH decreased from 2 to 60 days old in the submandibular glands. In the parotid glands the mean values for this enzyme were higher for the 2 days old group, and then decreased to remained more or less constant. The potential capacity of the pentose phosphate pathway was greater than that of glycolysis at early ages. The glycogen content showed similar variation in both glands. It was initially high and then decreased. In conclusion, our results on the activities of enzymes involved in carbohydrate metabolism in submandibular and parotid glands may be relevant to the initiation of saliva secretion in these animals. PMID:12642228

Nicolau, José; Ganzerla, Emily; de Souza, Douglas Nesadal

2003-02-01

341

Enhanced Na+/H+ Exchange Activity Contributes to the Pathogenesis of Muscular Dystrophy via Involvement of P2 Receptors  

PubMed Central

A subset of muscular dystrophy is caused by genetic defects in dystrophin-associated glycoprotein complex. Using two animal models (BIO14.6 hamsters and mdx mice), we found that Na+/H+ exchanger (NHE) inhibitors prevented muscle degeneration. NHE activity was constitutively enhanced in BIO myotubes, as evidenced by the elevated intracellular pH and enhanced 22Na+ influx, with activation of putative upstream kinases ERK42/44. NHE inhibitor significantly reduced the increases in baseline intracellular Ca2+ as well as Na+ concentration and stretch-induced damage, suggesting that Na+i-dependent Ca2+overload via the Na+/Ca2+ exchanger may cause muscle damage. Furthermore, ATP was found to be released continuously from BIO myotubes in a manner further stimulated by stretching and that the P2 receptor antagonists reduce the enhanced NHE activity and dystrophic muscle damage. These observations suggest that autocrine ATP release may be primarily involved in genesis of abnormal ionic homeostasis in dystrophic muscles and that Na+-dependent ion exchangers play a critical pathological role in muscular dystrophy.

Iwata, Yuko; Katanosaka, Yuki; Hisamitsu, Takashi; Wakabayashi, Shigeo

2007-01-01

342

Enhanced Na+/H+ exchange activity contributes to the pathogenesis of muscular dystrophy via involvement of P2 receptors.  

PubMed

A subset of muscular dystrophy is caused by genetic defects in dystrophin-associated glycoprotein complex. Using two animal models (BIO14.6 hamsters and mdx mice), we found that Na(+)/H(+) exchanger (NHE) inhibitors prevented muscle degeneration. NHE activity was constitutively enhanced in BIO myotubes, as evidenced by the elevated intracellular pH and enhanced (22)Na(+) influx, with activation of putative upstream kinases ERK42/44. NHE inhibitor significantly reduced the increases in baseline intracellular Ca(2+) as well as Na(+) concentration and stretch-induced damage, suggesting that Na(+)(i)-dependent Ca(2+)overload via the Na(+)/Ca(2+) exchanger may cause muscle damage. Furthermore, ATP was found to be released continuously from BIO myotubes in a manner further stimulated by stretching and that the P2 receptor antagonists reduce the enhanced NHE activity and dystrophic muscle damage. These observations suggest that autocrine ATP release may be primarily involved in genesis of abnormal ionic homeostasis in dystrophic muscles and that Na(+)-dependent ion exchangers play a critical pathological role in muscular dystrophy. PMID:17823278

Iwata, Yuko; Katanosaka, Yuki; Hisamitsu, Takashi; Wakabayashi, Shigeo

2007-09-06

343

Linear polyubiquitin chains: a new modifier involved in NF?B activation and chronic inflammation, including dermatitis.  

PubMed

The ubiquitin conjugation system regulates a wide variety of biological phenomena, including protein degradation and signal transduction, by regulating protein function via polyubiquitin conjugation in most cases. Several types of polyubiquitin chains exist in cells, and the type of polyubiquitin chain conjugated to a protein seems to determine how that protein is regulated. We identified a novel linear polyubiquitin chain and the ubiquitin-protein ligase complex that assembles it, designated LUBAC. Both were shown to have crucial roles in the canonical NF?B activation pathway. This year, three groups, including our laboratory, identified SHARPIN as a new subunit of LUBAC. Of great interest, Sharpin was identified as a causative gene of chronic proliferative dermatitis in mice (cpdm), which is characterized by numerous inflammatory symptoms including chronic dermatitis, arthritis and immune disorders. Deletion of SHARPIN drastically reduces the amount of LUBAC and attenuates signal-induced NF?B activation. The pleomorphic symptoms of cpdm mice suggest that LUBAC-mediated NF?B activation may play critical roles in mammals and be involved in various disorders. A forward look into the linear polyubiquitin research is also discussed. PMID:21900745

Iwai, Kazuhiro

2011-09-15

344

A novel mechanism of control of NF?B activation and inflammation involving A2B adenosine receptors  

PubMed Central

Summary The nuclear factor kappa B (NF?B) pathway controls a variety of processes, including inflammation, and thus, the regulation of NF?B has been a continued focus of study. Here, we report a newly identified regulation of this pathway, involving direct binding of the transcription factor NF?B1 (the p105 subunit of NF?B) to the C-terminus of the A2B adenosine receptor (A2BAR), independent of ligand activation. Intriguingly, binding of A2BAR to specific sites on p105 prevents polyubiquitylation and degradation of p105 protein. Ectopic expression of the A2BAR increases p105 levels and inhibits NF?B activation, whereas p105 protein levels are reduced in cells from A2BAR-knockout mice. In accordance with the known regulation of expression of anti- and pro-inflammatory cytokines by p105, A2BAR-null mice generate less interleukin (IL)-10, and more IL-12 and tumor necrosis factor (TNF-?). Taken together, our results show that the A2BAR inhibits NF?B activation by physically interacting with p105, thereby blocking its polyubiquitylation and degradation. Our findings unveil a surprising function for the A2BAR, and provide a novel mechanistic insight into the control of the NF?B pathway and inflammation.

Sun, Ying; Duan, Yuanyuan; Eisenstein, Anna S.; Hu, Wenbao; Quintana, Adrien; Lam, Wai Kwan; Wang, Yan; Wu, Zhenguo; Ravid, Katya; Huang, Pingbo

2012-01-01

345

Studies on the involvement of histamine in the hypothalamic-pituitary-adrenal axis activation induced by nerve growth factor.  

PubMed

Nerve growth factor (NGF) has been shown to stimulate the hypothalamic-pituitary-adrenocortical (HPA) axis. Since NGF induces the release of histamine from mast cells and in consideration of the fact that histamine is an HPA axis activator, we investigated whether NGF adrenocortical stimulation is mediated by histamine. To accomplish with it, the H1 histamine antagonist promethazine and the H2 antagonists metiamide and zolantidine were used in freely-moving cannulated rats. The increase in plasma corticosterone concentration induced by histamine administration was prevented completely by promethazine pretreatment but was unaffected by the H2 antagonists. Neither H1 nor H2 antagonists affected the adrenocortical stimulation induced by NGF administration. Moreover, since mast cells are reportedly present in the rat adrenal gland and the locally released histamine mediates the release of adrenaline which, in turn, stimulates glucocorticoid synthesis and secretion, we studied the effect of NGF on basal and ACTH-stimulated corticosterone release from in vitro isolated quartered adrenal glands and collagenase-dispersed adrenal cells. The results from these in vitro experiments have indicated that NGF modified neither spontaneous nor stimulated corticosterone release. Altogether these observations suggest that endogenous histamine is unlikely to be involved in HPA axis stimulation by NGF and reinforce the previously proposed concept of an active participation of NGF in the control of adrenocortical activity. PMID:11191621

Scaccianoce, S; Lombardo, K; Nicolai, R; Affricano, D; Angelucci, L

2000-11-17

346

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

2011-11-27

347

Alterations in local chromatin environment are involved in silencing and activation of subtelomeric var genes in Plasmodium falciparum  

PubMed Central

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), encoded by the var gene family, undergoes antigenic variation and plays an important role in chronic infection and severe malaria. Only a single var gene is transcribed per parasite, and epigenetic control mechanisms are fundamental in this strategy of mutually exclusive transcription. We show that subtelomeric upsB var gene promoters carried on episomes are silenced by default, and that promoter activation is sufficient to silence all other family members. However, they are active by default when placed downstream of a second active var promoter, underscoring the significance of local chromatin environment and nuclear compartmentalization in var promoter regulation. Native chromatin covering the SPE2-repeat array in upsB promoters is resistant to nuclease digestion, and insertion of these regulatory elements into a heterologous promoter causes local alterations in nucleosomal organization and promoter repression. Our findings suggest a common logic underlying the transcriptional control of all var genes, and have important implications for our understanding of the epigenetic processes involved in the regulation of this major virulence gene family.

Voss, Till S; Tonkin, Christopher J; Marty, Allison J; Thompson, Jennifer K; Healer, Julie; Crabb, Brendan S; Cowman, Alan F

2007-01-01

348

Possible involvement of TLRs and hemichannels in stress-induced CNS dysfunction via mastocytes, and glia activation.  

PubMed

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 Ca(2+) 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. PMID:23935250

Aguirre, Adam; Maturana, Carola J; Harcha, Paloma A; Sáez, Juan C

2013-07-02

349

A new variant activator involved in the degradation of phenolic compounds from a strain of Pseudomonas putida.  

PubMed

A new variant type of regulatory activator and relevant promoters (designated capR, Pr and Po) involved in the metabolism of phenolic compounds were cloned from Pseudomonas putida KCTC1452 by using PCR. The deduced amino acid sequence of CapR revealed a difference in nine amino acids from the effector binding domain of DmpR. To measure effector specificity, plasmids were constructed in such a way that the expression of luc gene for firefly luciferase or lacZ for beta-galactosidase as a reporter was under the control of capR. When Escherichia coli transformed with the plasmids was exposed to phenol, dramatic increases in the activity of luciferase or beta-galactosidase were observed in a range of 0.01-1 mM. Among various phenolic compounds tested, other effective compounds included catechol, 2-methylphenol, 3-methylphenol, 4-methylphenol, 2-chlorophenol, 4-chlorophenol, 2-nitrophenol, resorcinol, and 2, 5-dimethylphenol. The results indicate that CapR has effector specificity different from other related activators, CatR and DmpR. Waste water and soil potentially containing phenolic compounds were also tested by this system and the results were compared with chemical and GC data. The present results indicate that the biosensor consisting of capR and the promoters may be utilized for the development of a phenolic compounds-specific biosensor in monitoring the environmental pollutant. PMID:12890609

Park, Seun Mi; Park, Hoo Hwi; Lim, Woon Ki; Shin, Hae Ja

2003-08-15

350

Production of active recombinant eIF5A: reconstitution in E.coli of eukaryotic hypusine modification of eIF5A by its coexpression with modifying enzymes.  

PubMed

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N(?)-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation. PMID:21131325

Park, Jong Hwan; Dias, Camila A O; Lee, Seung Bum; Valentini, Sandro R; Sokabe, Masaaki; Fraser, Christopher S; Park, Myung Hee

2010-12-02

351

Production of active recombinant eIF5A: reconstitution in E.coli of eukaryotic hypusine modification of eIF5A by its coexpression with modifying enzymes  

PubMed Central

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N?-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation.

Park, Jong Hwan; Dias, Camila A. O.; Lee, Seung Bum; Valentini, Sandro R.; Sokabe, Masaaki; Fraser, Christopher S.; Park, Myung Hee

2011-01-01

352

Possible involvement of P2X7 receptor activation in microglial neuroprotection against focal cerebral ischemia in rats.  

PubMed

Microglia play important roles in the pathogenic cascade following cerebral ischemia, since they express growth factors, chemokines and regulatory cytokines as well as free radicals and other toxic mediators. P2X7 receptor, a subtype of a family of P2 purinoceptors, is primarily expressed in microglia and macrophages, suggesting that it regulates immune function and inflammatory responses. However, the involvement of ATP in such microglial responses after cerebral ischemia is not yet understood. In this study, we investigated the possible involvement of ATP, especially through the P2X7 receptors, in a rat model of focal cerebral ischemia. In immunohistochemical analysis, P2X7 receptor-like immunoreactivity was predominantly detected in microglia, and then activated microglia accumulated in the ischemic region, in rats subjected to middle cerebral artery occlusion (MCAO) and reperfusion. Intracerebroventricular injection with P2X7 receptor agonist 2'-3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) improved behavioral dysfunction accessed by rota-rod test and ischemic neural injury induced by MCAO. In contrast, P2X7 receptor antagonist adenosine 5'-triphosphate-2',3'-dialdehyde (OxATP) exacerbated ischemic brain damage. These results suggest that microglia play an important role in neuroprotection against rat cerebral ischemia, which is regulated by a P2X7 receptor-mediated ATP signal. PMID:18520042

Yanagisawa, Daijiro; Kitamura, Yoshihisa; Takata, Kazuyuki; Hide, Izumi; Nakata, Yoshihiro; Taniguchi, Takashi

2008-06-01

353

The medial amygdaloid nucleus is involved in the cardiovascular pathway activated by noradrenaline into the lateral septal area of rats.  

PubMed

We have previously reported that noradrenaline (NA) microinjected into the lateral septal area (LSA) caused pressor and bradicardic responses that were mediated by vasopressin release into the circulation through the paraventricular nucleus of hypothalamus (PVN). Although PVN is the final structure involved in the cardiovascular responses caused by NA in the LSA, there is no evidence of direct connections between these areas, suggesting that some structures could be links in this pathway. In the present study, we verified the effect of reversible synaptic inactivation of the medial amygdaloid nucleus (MeA), bed nucleus of stria terminalis (BNST) or diagonal band of Broca (DBB) with Cobalt Chloride (CoCl(2) ) on the cardiovascular response to NA microinjection into the LSA of unanesthetized rats. Male Wistar rats had guide cannulae implanted into the LSA and the MeA, BNST or DBB for drug administration, and a femoral catheter for blood pressure and heart rate recordings. Local microinjection of CoCl(2) (1 mm in 100 nL) into the MeA significantly reduced the pressor and bradycardic responses caused by NA microinjection (21 nmol in 200 nL) into the LSA. In contrast, microinjection of CoCl(2) into the BNST or DBB did not change the cardiovascular responses to NA into the LSA. The results indicate that synapses within the MeA, but not in BNST or DBB, are involved in the cardiovascular pathway activated by NA microinjection into the LSA. PMID:22805235

Scopinho, América A; Fortaleza, Eduardo A T; Corręa, Fernando M A

2012-07-15

354

Involvement of p53 in the cytotoxic activity of the NAMPT inhibitor FK866 in myeloid leukemic cells  

PubMed Central

FK866 is a specific inhibitor of NAMPT and induces apoptosis of leukemic cells by depletion of intracellular NAD+. Since up-regulation of NAMPT is associated with several cases of cancers, including leukemias, we asked whether in leukemic cells inhibition of NAMPT involves p53 pathway. We observed that FK866 induced apoptosis and reduced cell proliferation in NB-4, OCI-AML3 and MOLM-13 cell lines. In contrast, the leukemia cell lines, K-562 and Kasumi, containing nonfunctional p53 were relatively unaffected by FK866 treatment. Importantly, direct inhibition of sirtuins significantly reduced the viability of NB-4, OCI-AML3 and MOLM-13 cell lines. Activation of p53 by FK866 involved increased acetylation of p53 at lysine 382 with subsequent increase in the expression of p21 and BAX. Further, knockdown of p53 attenuated the effects of FK866 on apoptosis and cell cycle arrest, which was partly associated with decreased expression of p21 and BAX. Our results suggest the role of p53 acetylation pathway in the anti-leukemic effect of FK866.

Thakur, Basant Kumar; Dittrich, Tino; Chandra, Prakash; Becker, Annette; Kuehnau, Wolfgang; Klusmann, Jan-Henning; Reinhardt, Dirk; Welte, Karl

2013-01-01

355

Increased activity and involvement of caspase-3 in radiation-induced apoptosis in neural cells precursors from developing rat brain.  

PubMed

Using primary cultures of neural precursor cells of cortex from developing rat brain, we demonstrated the involvement of caspase-3 in the apoptotic process induced by gamma irradiation. The precursor nature of cells was confirmed by nestin and GFAP immunoreactivity and by the capacity of differentiation in neuronal and glial cells after 5 days in culture. Neural precursors were irradiated with single doses ranging from 0.1 to 4Gy. Cellular death, determined 24 h post-irradiation (pi) was dose-dependent and the induction of apoptosis was confirmed by nuclear condensation, DNA fragmentation and hypodiploid DNA peak represented by the "sub G1" region. For the higher doses, apoptosis was evident after 4-6 h pi and increased during 24 h. Caspase-3 activity increased with doses and was maximal at 4-6 h pi with 3Gy and remained similar with 4Gy. The protection from radiation-induced apoptosis by caspase-3 inhibitor, zDEVD-fmk, confirmed that this enzyme is involved in the apoptotic mechanism in this system. The possibility of using this tissue culture system for studying the effects of ionizing radiation on morphological and molecular differentiation was considered. PMID:15019301

Michelin, Severino; del Rosario Perez, Maria; Dubner, Diana; Gisone, Pablo

2004-03-01

356

Isolation and DNA-binding characteristics of a protein involved in transcription activation of two divergently transcribed, essential yeast genes.  

PubMed Central

We have identified a protein, BAF1, which has two oppositely oriented, partially overlapping binding sites within a symmetrical sequence located midway between and upstream of the divergently transcribed YPT1 and TUB2 genes of the yeast Saccharomyces cerevisiae. The 120 kd BAF1 protein was purified to near homogeneity and used to delineate the two binding sites and to identify apparent protein contact sites by the missing contact technique, methylation interference and by site-directed mutagenesis. The BAF1-recognition sequence contains a conserved TCN7ACG element recently identified at autonomously replicating sequences (ARS) and in the 5' and 3' flanking region of other yeast genes. The symmetrical sequence of the YPT1/TUB2 intergene region seems not to be involved in DNA replication but activates transcription in an orientation-independent fashion. Images

Halfter, H; Muller, U; Winnacker, E L; Gallwitz, D

1989-01-01

357

[Activities of the nurse involved in triage/risk classification assessment in emergency services: an integrative review].  

PubMed

This present study aimed at identifying and assessing available literature regarding the activities of the nurse involved in assessing risk classification in emergency services. The integrative review carried out searches in the following databases: Science Direct, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Medical Literature Analysis and Retrieval System Online (MEDLINE), Latin-American and Caribbean Health Sciences Database (LILACS), and Scientific Electronic Library Online (SCIELO). Twenty-two articles that met inclusion criteria were selected. Results indicated that the major attributions of this professional are the assessment of the patient's healthcare status and decision-making, a process that demands clinical knowledge and experience The nurse is capable of organizing the workflow of patients according to the priority of the rendered care and service demands, and stands out as a professional of excellence in the development of triage/risk classification practices in emergency services. PMID:23596933

Acosta, Aline Marques; Duro, Carmen Lucia Mottin; Lima, Maria Alice Dias da Silva

2012-12-01

358

Tissue Plasminogen Activator Activates NF-?B through a Pathway Involving Annexin A2/CD11b and Integrin-Linked Kinase  

PubMed Central

NF-?B activation is central to the initiation and progression of inflammation, which contributes to the pathogenesis of CKD. Tissue plasminogen activator (tPA) modulates the NF-?B pathway, but the underlying mechanism remains unknown. We investigated the role of tPA signaling in macrophage NF-?B activation and found that tPA activated NF-?B in a time- and dose-dependent manner. tPA also induced the expression of the NF-?B–dependent chemokines IP-10 and MIP-1?. The protease-independent action of tPA required its membrane receptor, annexin A2. tPA induced the aggregation and interaction of annexin A2 with integrin CD11b, and ablation of CD11b or administration of anti-CD11b neutralizing antibody abolished the effect of tPA. Knockdown of the downstream effector of CD11b, integrin-linked kinase, or disruption of its engagement with CD11b also blocked tPA-induced NF-?B signaling. In vivo, tPA-knockout mice had reduced NF-?B signaling, fewer renal macrophages, and less collagen deposition than their counterparts. Taken together, these data suggest that tPA activates the NF-?B pathway in macrophages through a signaling pathway involving annexin A2/CD11b-mediated integrin-linked kinase.

Lin, Ling; Wu, Chuanyue

2012-01-01

359

Involvement of Dopamine Receptors in Binge Methamphetamine-Induced Activation of Endoplasmic Reticulum and Mitochondrial Stress Pathways  

PubMed Central

Single large doses of methamphetamine (METH) cause endoplasmic reticulum (ER) stress and mitochondrial dysfunctions in rodent striata. The dopamine D1 receptor appears to be involved in these METH-mediated stresses. The purpose of this study was to investigate if dopamine D1 and D2 receptors are involved in ER and mitochondrial stresses caused by single-day METH binges in the rat striatum. Male Sprague-Dawley rats received 4 injections of 10 mg/kg of METH alone or in combination with a putative D1 or D2 receptor antagonist, SCH23390 or raclopride, respectively, given 30 min prior to each METH injection. Rats were euthanized at various timepoints afterwards. Striatal tissues were used in quantitative RT-PCR and western blot analyses. We found that binge METH injections caused increased expression of the pro-survival genes, BiP/GRP-78 and P58IPK, in a SCH23390-sensitive manner. METH also caused up-regulation of ER-stress genes, Atf2, Atf3, Atf4, CHOP/Gadd153 and Gadd34. The expression of heat shock proteins (HSPs) was increased after METH injections. SCH23390 completely blocked induction in all analyzed ER stress-related proteins that included ATF3, ATF4, CHOP/Gadd153, HSPs and caspase-12. The dopamine D2-like antagonist, raclopride, exerted small to moderate inhibitory influence on some METH-induced changes in ER stress proteins. Importantly, METH caused decreases in the mitochondrial anti-apoptotic protein, Bcl-2, but increases in the pro-apoptotic proteins, Bax, Bad and cytochrome c, in a SCH23390-sensitive fashion. In contrast, raclopride provided only small inhibition of METH-induced changes in mitochondrial proteins. These findings indicate that METH-induced activation of striatal ER and mitochondrial stress pathways might be more related to activation of SCH23390-sensitive receptors.

Beauvais, Genevieve; Atwell, Kenisha; Jayanthi, Subramaniam; Ladenheim, Bruce; Cadet, Jean Lud

2011-01-01

360

Involvement of dopamine receptors in binge methamphetamine-induced activation of endoplasmic reticulum and mitochondrial stress pathways.  

PubMed

Single large doses of methamphetamine (METH) cause endoplasmic reticulum (ER) stress and mitochondrial dysfunctions in rodent striata. The dopamine D(1) receptor appears to be involved in these METH-mediated stresses. The purpose of this study was to investigate if dopamine D(1) and D(2) receptors are involved in ER and mitochondrial stresses caused by single-day METH binges in the rat striatum. Male Sprague-Dawley rats received 4 injections of 10 mg/kg of METH alone or in combination with a putative D(1) or D(2) receptor antagonist, SCH23390 or raclopride, respectively, given 30 min prior to each METH injection. Rats were euthanized at various timepoints afterwards. Striatal tissues were used in quantitative RT-PCR and western blot analyses. We found that binge METH injections caused increased expression of the pro-survival genes, BiP/GRP-78 and P58(IPK), in a SCH23390-sensitive manner. METH also caused up-regulation of ER-stress genes, Atf2, Atf3, Atf4, CHOP/Gadd153 and Gadd34. The expression of heat shock proteins (HSPs) was increased after METH injections. SCH23390 completely blocked induction in all analyzed ER stress-related proteins that included ATF3, ATF4, CHOP/Gadd153, HSPs and caspase-12. The dopamine D(2)-like antagonist, raclopride, exerted small to moderate inhibitory influence on some METH-induced changes in ER stress proteins. Importantly, METH caused decreases in the mitochondrial anti-apoptotic protein, Bcl-2, but increases in the pro-apoptotic proteins, Bax, Bad and cytochrome c, in a SCH23390-sensitive fashion. In contrast, raclopride provided only small inhibition of METH-induced changes in mitochondrial proteins. These findings indicate that METH-induced activation of striatal ER and mitochondrial stress pathways might be more related to activation of SCH23390-sensitive receptors. PMID:22174933

Beauvais, Genevieve; Atwell, Kenisha; Jayanthi, Subramaniam; Ladenheim, Bruce; Cadet, Jean Lud

2011-12-13

361

Identification of a Bidirectional Splicing Enhancer: Differential Involvement of SR Proteins in 5? or 3? Splice Site Activation  

PubMed Central

The adenovirus E1A pre-mRNA undergoes alternative splicing whose modulation occurs during infection, through the use of three different 5? splice sites and of one major or one minor 3? splice site. Although this pre-mRNA has been extensively used as a model to compare the transactivation properties of SR proteins, no cis-acting element has been identified in the transcript sequence. Here we describe the identification and the characterization of a purine-rich splicing enhancer, located just upstream of the 12S 5? splice site, which is formed from two contiguous 9-nucleotide (nt) purine motifs (Pu1 and Pu2). We demonstrate that this sequence is a bidirectional splicing enhancer (BSE) in vivo and in vitro, because it activates both the downstream 12S 5? splice site through the Pu1 motif and the upstream 216-nt intervening sequence (IVS) 3? splice site through both motifs. UV cross-linking and immunoprecipitation experiments indicate that the BSE interacts with several SR proteins specifically, among them 9G8 and ASF/SF2, which bind preferentially to the Pu1 and Pu2 motifs, respectively. Interestingly, we show by in vitro complementation assays that SR proteins have distinct transactivatory properties. In particular, 9G8, but not ASF/SF2 or SC35, is able to strongly activate the recognition of the 12S 5? splice site in a BSE-dependent manner in wild-type E1A or in a heterologous context, whereas ASF/SF2 or SC35, but not 9G8, activates the upstream 216-nt IVS splicing. Thus, our results identify a novel exonic BSE and the SR proteins which are involved in its differential activity.

Bourgeois, Cyril F.; Popielarz, Michel; Hildwein, Georges; Stevenin, James

1999-01-01

362

Increase in Anthraquinone Content in Rubia cordifolia Cells Transformed by rol Genes Does Not Involve Activation of the NADPH Oxidase Signaling Pathway  

Microsoft Academic Search

It has been reported that rol plant oncogenes located in Ri-plasmids of Agrobacterium rhizogenes activated synthesis of secondary metabolites in the transformed plant cells. The activator mechanism is still unknown. In this work, we studied whether the NADPH oxidase-signaling pathway, which regulates the synthesis of defense metabolites in plants, is involved in the activator function of the rol genes. It

V. P. Bulgakov; G. K. Tchernoded; N. P. Mischenko; Yu. N. Shkryl; V. P. Glazunov; S. A. Fedoreyev; Yu. N. Zhuravlev

2003-01-01

363

Proteasomes regulate erythropoietin receptor and signal transducer and activator of transcription 5 (STAT5) activation. Possible involvement of the ubiquitinated Cis protein.  

PubMed

Cis is an Src homology 2 domain-containing protein, which binds to the erythropoietin receptor and decreases erythropoietin-stimulated cell proliferation. We show that Cis associates with the second tyrosine residue of the intracellular domain of the erythropoietin receptor (Tyr401). Two forms of Cis with molecular masses of 32 and 37 kDa were detected, and we demonstrate that the 37-kDa protein resulted from post-translational modifications of the 32-kDa form. Anti-ubiquitin antibodies recognized the 37-kDa form of Cis and the proteasome inhibitors N-acetyl-leucyl-leucyl-norleucinal and lactacystin inhibited its degradation, showing that the 37-kDa form of Cis is a ubiquitinated protein, which seems to be rapidly degraded by the proteasome. In erythropoietin-stimulated UT-7 cells, the activation of the erythropoietin receptor and signal transducer and activator of transcription 5 (STAT5) was transient and returned to basal levels after 30-60 min of erythropoietin stimulation. In contrast, these proteins remained strongly phosphorylated, and STAT5 remained activated for at least 120 min in the presence of proteasome inhibitors. These experiments demonstrate that the proteasomes are involved in the down-regulation of the erythropoietin receptor activation signals. Because the proteasome inhibitors induced the accumulation of both the ubiquitinated form of Cis and the Cis-erythropoietin receptor complexes, our results suggest that the ubiquitinated form of Cis could be involved in the proteasome-mediated inactivation of the erythropoietin receptor. PMID:9774439

Verdier, F; Chrétien, S; Muller, O; Varlet, P; Yoshimura, A; Gisselbrecht, S; Lacombe, C; Mayeux, P

1998-10-23

364

Interleukin-2 inhibits glucocorticoid receptor transcriptional activity through a mechanism involving STAT5 (signal transducer and activator of transcription 5) but not AP-1.  

PubMed

Cytokines and glucocorticoids (GCs) signaling pathways interfere with each other in the regulation of apoptosis and gene expression in the immune system. Interleukin-2 (IL-2), through the Janus kinase/signal transducers and activators of transcription (Jak/STAT) and mitogen-activated protein kinase (MAPK) pathways, activates STAT5 and activated protein-1 (AP-1) transcription factors, respectively, which are known to repress glucocorticoid receptor (GR) activity, at least in part, through protein-protein interactions. In this work, we have analyzed the mechanisms whereby IL-2 down-regulates the GC-induced transactivation of the mouse mammary tumor virus long terminal repeat (MMTV-LTR) in murine CTLL-2 T lymphocytes. Mutagenesis studies revealed that the MMTV-LTR STAT5 binding site (-923/-914) was not required for IL-2-mediated inhibition but identified both glucocorticoid response elements (GREs) and the -104/+1 region as critical elements for this negative response. The DNA binding activities of transcription factors required for GC-mediated activation of the MMTV-LTR promoter and that bind to the -104/+1 region (nuclear factor-1, Oct-1) were not affected by IL-2 treatment. Overexpression of wild-type STAT5B enhanced the effect of IL-2 on MMTV-LTR activity, and a dominant negative form of STAT5B (Y699F) abolished the IL-2-mediated MMTV-LTR inhibition, whereas AP-1 activation had no effect in this system. Direct interaction between liganded GR and STAT5 was observed in CTLL-2 cells in a STAT5 phosphorylation-independent manner. Overexpression of nuclear coactivators CBP (CREB-binding protein) or SRC-1a (steroid receptor coactivator 1a) did not blunt IL-2 inhibitory effects. We suggest that the STAT5-repressive activity on the GC-dependent transcription may involve direct interaction of STAT5 with GR, is dependent on the promoter context and STAT5 activation level, and occurs independently of coactivators levels in T cells. PMID:11435608

Biola, A; Lefebvre, P; Perrin-Wolff, M; Sturm, M; Bertoglio, J; Pallardy, M

2001-07-01

365

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

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

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

2003-11-05

368

Functional domains of the bacteriophage P2 scaffolding protein: identification of residues involved in assembly and protease activity.  

PubMed

Bacteriophage P2 encodes a scaffolding protein, gpO, which is required for correct assembly of P2 procapsids from the gpN major capsid protein. The 284 residue gpO protein also acts as a protease, cleaving itself into an N-terminal fragment, O, that remains in the capsid following maturation. In addition, gpO is presumed to act as the maturation protease for gpN, which is N-terminally processed to N, accompanied by DNA packaging and capsid expansion. The protease activity of gpO resides in the N-terminal half of the protein. We show that gpO is a classical serine protease, with a catalytic triad comprised of Asp 19, His 48 and Ser 107. The C-terminal 90 amino acids of gpO are required and sufficient for capsid assembly. This fragment contains a predicted alpha-helical segment between residues 197 and 257 and exists as a multimer in solution, suggesting that oligomerization is required for scaffolding activity. Correct assembly requires the C-terminal cysteine residue, which is most likely involved in transient gpN interactions. Our results suggest a model for gpO scaffolding action in which the N-terminal half of gpO binds strongly to gpN, while oligomerization of the C-terminal alpha-helical domain of gpO and transient interactions between Cys 284 and gpN lead to capsid assembly. PMID:19064277

Chang, Jenny R; Spilman, Michael S; Rodenburg, Cynthia M; Dokland, Terje

2008-12-06

369

Increased origin activity in transformed versus normal cells: identification of novel protein players involved in DNA replication and cellular transformation  

PubMed Central

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.

Di Paola, Domenic; Rampakakis, Emmanouil; Chan, Man Kid; Arvanitis, Dina N.; Zannis-Hadjopoulos, Maria

2010-01-01

370

Morus alba and active compound oxyresveratrol exert anti-inflammatory activity via inhibition of leukocyte migration involving MEK/ERK signaling  

PubMed Central

Background Morus alba has long been used in traditional Chinese medicine to treat inflammatory diseases; however, the scientific basis for such usage and the mechanism of action are not well understood. This study investigated the action of M. alba on leukocyte migration, one key step in inflammation. Methods Gas chromatography-mass spectrometry (GC-MS) and cluster analyses of supercritical CO2 extracts of three Morus species were performed for chemotaxonomy-aided plant authentication. Phytochemistry and CXCR4-mediated chemotaxis assays were used to characterize the chemical and biological properties of M. alba and its active compound, oxyresveratrol. fluorescence-activated cell sorting (FACS) and Western blot analyses were conducted to determine the mode of action of oxyresveratrol. Results Chemotaxonomy was used to help authenticate M. alba. Chemotaxis-based isolation identified oxyresveratrol as an active component in M. alba. Phytochemical and chemotaxis assays showed that the crude extract, ethyl acetate fraction and oxyresveratrol from M. alba suppressed cell migration of Jurkat T cells in response to SDF-1. Mechanistic study indicated that oxyresveratrol diminished CXCR4-mediated T-cell migration via inhibition of the MEK/ERK signaling cascade. Conclusions A combination of GC-MS and cluster analysis techniques are applicable for authentication of the Morus species. Anti-inflammatory benefits of M. alba and its active compound, oxyresveratrol, may involve the inhibition of CXCR-4-mediated chemotaxis and MEK/ERK pathway in T and other immune cells.

2013-01-01

371

Structures of Rhodopsin Kinase in Different Ligand States Reveal Key Elements Involved in G Protein-coupled Receptor Kinase Activation*S?  

PubMed Central

G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate activated heptahelical receptors, leading to their uncoupling from G proteins. Here we report six crystal structures of rhodopsin kinase (GRK1), revealing not only three distinct nucleotide-binding states of a GRK but also two key structural elements believed to be involved in the recognition of activated GPCRs. The first is the C-terminal extension of the kinase domain, which was observed in all nucleotide-bound GRK1 structures. The second is residues 5-30 of the N terminus, observed in one of the GRK1·(Mg2+)2·ATP structures. The N terminus was also clearly phosphorylated, leading to the identification of two novel phosphorylation sites by mass spectral analysis. Co-localization of the N terminus and the C-terminal extension near the hinge of the kinase domain suggests that activated GPCRs stimulate kinase activity by binding to this region to facilitate full closure of the kinase domain.

Singh, Puja; Wang, Benlian; Maeda, Tadao; Palczewski, Krzysztof; Tesmer, John J. G.

2008-01-01

372

Fluorescence activated cell sorting (FACS) using RNAlater to minimize RNA degradation and perturbation of mRNA expression from cells involved in initial host microbe interactions.  

PubMed

Host microbe interactions frequently involve specific cellular tropism. Accurate characterization of cells involved in these initial interactions is complicated by the response to the microbe. We describe a method utilizing RNAlater for Fluorescence Activated Cell Sorting of these critical cells that minimizes the downstream perturbation in the gene expression profile. PMID:17512621

Nishimoto, Kevin P; Newkirk, Daniel; Hou, Stephen; Fruehauf, John; Nelson, Edward L

2007-04-12

373

The Impact of Student Membership in Black Greek-Letter Organizations on Black Students' Involvement in Collegiate Activities and Their Development of Leadership Skills.  

ERIC Educational Resources Information Center

|Examined the impact of Black Greek-Letter organization (BGO) membership on black students, involvement in campus-related activities, and leadership development. Results from a sample of 1,400 black students show that BGO members demonstrate greater student involvement and have more confidence in their leadership abilities. (SLD)|

Kimbrough, Walter M.; Hutcheson, Philo A.

1998-01-01

374

Enzymatic activities involved in the DNA resynthesis step of nucleotide excision repair are firmly attached to chromatin.  

PubMed Central

In this study the role of nuclear architecture in nucleotide excision repair (NER) was investigated by gentle dismantling of the cell and probing the capability of chromatin to carry out repair in vitro. The rationale behind this approach is that compartmentalization of NER at nuclear structures would make the enzymatic activities refractory to extraction by buffers that solubilize cellular membranes. In order to obtain intact chromatin primary human fibroblasts were encapsulated in agarose microbeads and lysed in isotonic buffers containing the non-ionic detergent Triton X-100. Under these conditions the majority of cellular proteins diffuse out of the beads, but the remaining chromatin is able to replicate and to transcribe DNA in the presence of triphosphates and Mg2+. UV irradiation of confluent repair-proficient human fibroblasts prior to lysis stimulated the incorporation of deoxynucleotide triphosphates in Triton X-100-isolated chromatin, even under stringent lysis conditions. In addition, experiments with UV-sensitive xeroderma pigmentosum (complementation groups A and C) and Cockayne's syndrome fibroblasts (complementation group A) revealed that this repair synthesis was due to global genome repair activity. Transcription-coupled repair was only detectable in cells permeabilized by streptolysin O (SLO). Repair synthesis in Triton X-100-isolated chromatin amounted to 15% of the total repair synthesis as measured in SLO-permeabilized cells. To allow the detection of these activities in vitro, presynthesis complexes have to be formed in intact cells, indicating that chromatin from Triton X-100-lysed cells is unable to initiate NER in vitro. Our data indicate that the components involved in the resynthesis step of NER are tightly associated with chromatin. A substantial fraction of total proliferating cell nuclear antigen (PCNA), which is required for the resynthesis step in NER, has been reported to become Triton X-100 non-extractable and tightly associated with nuclear structures after UV irradiation of cells. We propose that Triton X-100-resistant repair synthesis might be mediated by this chromatin-bound fraction of total PCNA.

Bouayadi, K; van der Leer-van Hoffen, A; Balajee, A S; Natarajan, A T; van Zeeland, A A; Mullenders, L H

1997-01-01

375

Activation of reciprocal pathways between arcuate nucleus and ventrolateral periaqueductal gray during electroacupuncture: involvement of VGLUT3.  

PubMed

Electroacupuncture (EA) at the Jianshi-Neiguan acupoints (P5-P6, overlying the median nerve) attenuates sympathoexcitatory responses through activation of the arcuate nucleus (ARC) and ventrolateral periaqueductal gray (vlPAG). Activation of the ARC or vlPAG respectively leads to neuronal excitation of the both nuclei during EA. However, direct projections between these two nuclei that could participate in central neural processing during EA have not been identified. The vesicular glutamate transporter 3 (VGLUT3) marks glutamatergic neurons. Thus, the present study evaluated direct neuronal projections between the ARC and vlPAG during EA, focusing on neurons containing VGLUT3. Seven to ten days after unilateral microinjection of a rodamine-conjugated microsphere retrograde tracer (100nl) into the vlPAG or ARC, rats were subjected to EA or served as a sham-operated control. Low frequency (2Hz) EA was performed bilaterally for 30min at the P5-P6 acupoints. Perikarya containing the microsphere tracer were found in the ARC and vlPAG of both groups. Compared to controls (needle placement without electrical stimulation), c-Fos immunoreactivity and neurons double-labeled with c-Fos, an immediate early gene and the tracer were increased significantly in the ARC and vlPAG of EA-treated rats (both P<0.01). Moreover, some neurons were triple-labeled with c-Fos, the retrograde tracer and VGLUT3 in the two nuclei following EA stimulation (P<0.01, both nuclei). These results suggest that direct reciprocal projections between the ARC and vlPAG are available to participate in prolonged modulation by EA of sympathetic activity and that VGLUT3-containing neurons are an important neuronal phenotype involved in this process. PMID:20836994

Guo, Zhi-Ling; Longhurst, John C

2010-09-15

376

Activation of reciprocal pathways between arcuate nucleus and ventrolateral periaqueductal gray during electroacupuncture: involvement of VGLUT3  

PubMed Central

Electroacupuncture (EA) at the Jianshi-Neiguan acupoints (P5-P6, overlying the median nerve) attenuates sympathoexcitatory responses through activation of the arcuate nucleus (ARC) and ventrolateral periaqueductal gray (vlPAG). Activation of the ARC or vlPAG respectively leads to neuronal excitation of the both nuclei during EA. However, direct projections between these two nuclei that could participate in central neural processing during EA have not been identified. The vesicular glutamate transporter 3 (VGLUT3) marks glutamatergic neurons. Thus, the present study evaluated direct neuronal projections between the ARC and vlPAG during EA, focusing on neurons containing VGLUT3. Seven to ten days after unilateral microinjection of a rodamine-conjugated microsphere retrograde tracer (100 nl) into the vlPAG or ARC, rats were subjected to EA or served as a sham-operated control. Low frequency (2 Hz) EA was performed bilaterally for 30 min at the P5-P6 acupoints. Perikarya containing the microsphere tracer were found in the ARC and vlPAG of both groups. Compared to controls (needle placement without electrical stimulation), c-Fos immunoreactivity and neurons double-labeled with c-Fos, an immediate early gene and the tracer were increased significantly in the ARC and vlPAG of EA-treated rats (both P<0.01). Moreover, some neurons were triple-labeled with c-Fos, the retrograde tracer and VGLUT3 in the two nuclei following EA stimulation (P<0.01, both nuclei). These results suggest that direct reciprocal projections between the ARC and vlPAG are available to participate in prolonged modulation by EA of sympathetic activity and that VGLUT3-containing neurons are an important neuronal phenotype involved in this process.

Guo, Zhi-Ling; Longhurst, John C.

2010-01-01

377

Activation of genes encoding mitochondrial proteins involved in alternative and uncoupled respiration of tomato plants treated with low temperature and reactive oxygen species  

Microsoft Academic Search

Using Real-time PCR, the regulation of gene expression for proteins involved in alternative and uncoupled respiration in tomato\\u000a (Lycopersicon esculentum Mill.) seedlings and cell culture was studied. The temperature of 4°C activated transcription of these genes. The effect\\u000a of low temperature on the activities of a number of enzymes involved in oxidative metabolism of seedlings and cultivated cells\\u000a was detected

V. N. Popov; A. T. Eprintsev; E. V. Maltseva

2011-01-01

378

Host cell entry of respiratory syncytial virus involves macropinocytosis followed by proteolytic activation of the F protein.  

PubMed

Respiratory Syncytial Virus (RSV) is a highly pathogenic member of the Paramyxoviridae that causes severe respiratory tract infections. Reports in the literature have indicated that to infect cells the incoming viruses either fuse their envelope directly with the plasma membrane or exploit clathrin-mediated endocytosis. To study the entry process in human tissue culture cells (HeLa, A549), we used fluorescence microscopy and developed quantitative, FACS-based assays to follow virus binding to cells, endocytosis, intracellular trafficking, membrane fusion, and infection. A variety of perturbants were employed to characterize the cellular processes involved. We found that immediately after binding to cells RSV activated a signaling cascade involving the EGF receptor, Cdc42, PAK1, and downstream effectors. This led to a series of dramatic actin rearrangements; the cells rounded up, plasma membrane blebs were formed, and there was a significant increase in fluid uptake. If these effects were inhibited using compounds targeting Na?/H? exchangers, myosin II, PAK1, and other factors, no infection was observed. The RSV was rapidly and efficiently internalized by an actin-dependent process that had all hallmarks of macropinocytosis. Rather than fusing with the plasma membrane, the viruses thus entered Rab5-positive, fluid-filled macropinosomes, and fused with the membranes of these on the average 50 min after internalization. Rab5 was required for infection. To find an explanation for the endocytosis requirement, which is unusual among paramyxoviruses, we analyzed the fusion protein, F, and could show that, although already cleaved by a furin family protease once, it underwent a second, critical proteolytic cleavage after internalization. This cleavage by a furin-like protease removed a small peptide from the F1 subunits, and made the virus infectious. PMID:23593008

Krzyzaniak, Magdalena Anna; Zumstein, Michael Thomas; Gerez, Juan Atilio; Picotti, Paola; Helenius, Ari

2013-04-11

379

Hyperforin Inhibits Akt1 Kinase Activity and Promotes Caspase-Mediated Apoptosis Involving Bad and Noxa Activation in Human Myeloid Tumor Cells  

PubMed Central

Background The natural phloroglucinol hyperforin HF displays anti-inflammatory and anti-tumoral properties of potential pharmacological interest. Acute myeloid leukemia (AML) cells abnormally proliferate and escape apoptosis. Herein, the effects and mechanisms of purified HF on AML cell dysfunction were investigated in AML cell lines defining distinct AML subfamilies and primary AML cells cultured ex vivo. Methodology and Results HF inhibited in a time- and concentration-dependent manner the growth of AML cell lines (U937, OCI-AML3, NB4, HL-60) by inducing apoptosis as evidenced by accumulation of sub-G1 population, phosphatidylserine externalization and DNA fragmentation. HF also induced apoptosis in primary AML blasts, whereas normal blood cells were not affected. The apoptotic process in U937 cells was accompanied by downregulation of anti-apoptotic Bcl-2, upregulation of pro-apoptotic Noxa, mitochondrial membrane depolarization, activation of procaspases and cleavage of the caspase substrate PARP-1. The general caspase inhibitor Z-VAD-fmk and the caspase-9- and -3-specific inhibitors, but not caspase-8 inhibitor, significantly attenuated apoptosis. HF-mediated apoptosis was associated with dephosphorylation of active Akt1 (at Ser473) and Akt1 substrate Bad (at Ser136) which activates Bad pro-apoptotic function. HF supppressed the kinase activity of Akt1, and combined treatment with the allosteric Akt1 inhibitor Akt-I-VIII significantly enhanced apoptosis of U937 cells. Significance Our data provide new evidence that HF's pro-apoptotic effect in AML cells involved inhibition of Akt1 signaling, mitochondria and Bcl-2 members dysfunctions, and activation of procaspases -9/-3. Combined interruption of mitochondrial and Akt1 pathways by HF may have implications for AML treatment.

Merhi, Faten; Tang, Ruoping; Piedfer, Marion; Mathieu, Julie; Bombarda, Isabelle; Zaher, Murhaf; Kolb, Jean-Pierre; Billard, Christian; Bauvois, Brigitte

2011-01-01

380

A novel activation of Ca2+-activated Cl? channel in Xenopus oocytes by Ginseng saponins: evidence for the involvement of phospholipase C and intracellular Ca2+ mobilization  

PubMed Central

The signal transduction mechanism of ginsenosides, the active ingredients of ginseng, was studied in Xenopus oocytes using two-electrode voltage-clamp technique. Ginseng total saponin (GTS), i.e., an unfractionated mixture of ginsenosides produced a large outward current at membrane potentials more positive than ?20?mV when it was applied to the exterior of oocytes, but not when injected intracellularly. The effect of GTS was concentration-dependent (EC50: 4.4??g?ml?1) and reversible. Certain fractionated ginsenosides (Rb1, Rb2, Rc, Rf, Rg2 and Ro) also produced an outward current in a concentration-dependent manner with the order of potency of Rf>Ro>Rb1=Rb2>Rg2>Rc. Other ginsenosides (Rd, Re and Rg1) had little or no effect. The GTS effect was completely blocked by bath application of the Ca2+-activated Cl? channel blocker niflumic acid and by intracellular injection of the calcium chelator BAPTA or the IP3 receptor antagonist heparin. Also, the effect was partially blocked by bath-applied U-73122, a phospholipase C (PLC) inhibitor and by intracellularly injected GTP?S, a non-hydrolyzable GTP analogue. Whereas, it was not altered by pertussin toxin (PTX) pretreatment. These results indicate that: (1) interaction of ginsenosides with membrane component(s) at the extracellular side leads to Ca2+-activated Cl? channel opening in Xenopus oocyte membrane; and (2) this process involves PLC activation, the release of Ca2+ from the IP3-sensitive intracellular store and PTX-insensitive G protein activation.

Choi, Seok; Rho, Seong-Hwan; Jung, Se-Yeon; Kim, Seok-Chang; Park, Chul-Seung; Nah, Seung-Yeol

2001-01-01

381

Early peroxisome proliferator-activated receptor gamma regulated genes involved in expansion of pancreatic beta cell mass  

PubMed Central

Background The progression towards type 2 diabetes depends on the allostatic response of pancreatic beta cells to synthesise and secrete enough insulin to compensate for insulin resistance. The endocrine pancreas is a plastic tissue able to expand or regress in response to the requirements imposed by physiological and pathophysiological states associated to insulin resistance such as pregnancy, obesity or ageing, but the mechanisms mediating beta cell mass expansion in these scenarios are not well defined. We have recently shown that ob/ob mice with genetic ablation of PPAR?2, a mouse model known as the POKO mouse failed to expand its beta cell mass. This phenotype contrasted with the appropriate expansion of the beta cell mass observed in their obese littermate ob/ob mice. Thus, comparison of these models islets particularly at early ages could provide some new insights on early PPAR? dependent transcriptional responses involved in the process of beta cell mass expansion Results Here we have investigated PPAR? dependent transcriptional responses occurring during the early stages of beta cell adaptation to insulin resistance in wild type, ob/ob, PPAR?2 KO and POKO mice. We have identified genes known to regulate both the rate of proliferation and the survival signals of beta cells. Moreover we have also identified new pathways induced in ob/ob islets that remained unchanged in POKO islets, suggesting an important role for PPAR? in maintenance/activation of mechanisms essential for the continued function of the beta cell. Conclusions Our data suggest that the expansion of beta cell mass observed in ob/ob islets is associated with the activation of an immune response that fails to occur in POKO islets. We have also indentified other PPAR? dependent differentially regulated pathways including cholesterol biosynthesis, apoptosis through TGF-? signaling and decreased oxidative phosphorylation.

2011-01-01

382

Formation of a tyrosine adduct involved in lignin degradation by Trametopsis cervina lignin peroxidase: a novel peroxidase activation mechanism.  

PubMed

LiP (lignin peroxidase) from Trametopsis cervina has an exposed catalytic tyrosine residue (Tyr181) instead of the tryptophan conserved in other lignin-degrading peroxidases. Pristine LiP showed a lag period in VA (veratryl alcohol) oxidation. However, VA-LiP (LiP after treatment with H2O2 and VA) lacked this lag, and H2O2-LiP (H2O2-treated LiP) was inactive. MS analyses revealed that VA-LiP includes one VA molecule covalently bound to the side chain of Tyr181, whereas H2O2-LiP contains a hydroxylated Tyr181. No adduct is formed in the Y171N variant. Molecular docking showed that VA binding is favoured by sandwich ? stacking with Tyr181 and Phe89. EPR spectroscopy after peroxide activation of the pre-treated LiPs showed protein radicals other than the tyrosine radical found in pristine LiP, which were assigned to a tyrosine-VA adduct radical in VA-LiP and a dihydroxyphenyalanine radical in H2O2-LiP. Both radicals are able to oxidize large low-redox-potential substrates, but H2O2-LiP is unable to oxidize high-redox-potential substrates. Transient-state kinetics showed that the tyrosine-VA adduct strongly promotes (>100-fold) substrate oxidation by compound II, the rate-limiting step in catalysis. The novel activation mechanism is involved in ligninolysis, as demonstrated using lignin model substrates. The present paper is the first report on autocatalytic modification, resulting in functional alteration, among class II peroxidases. PMID:23548202

Miki, Yuta; Pogni, Rebecca; Acebes, Sandra; Lucas, Fátima; Fernández-Fueyo, Elena; Baratto, Maria Camilla; Fernández, María I; de los Ríos, Vivian; Ruiz-Dueńas, Francisco J; Sinicropi, Adalgisa; Basosi, Riccardo; Hammel, Kenneth E; Guallar, Victor; Martínez, Angel T

2013-06-15

383

Defining amino acid residues involved in DNA-protein interactions and revelation of 3'-exonuclease activity in endonuclease V.  

PubMed

Endonuclease V is an enzyme that initiates a conserved DNA repair pathway by making an endonucleolytic incision at the 3' side one nucleotide from a deaminated base lesion. Site-directed mutagenesis analysis was conducted at seven conserved motifs of the thermostable Thermotoga maritima endonuclease V to probe for residues that affect DNA-protein interactions. Y80, G83, and L85 in motif III, H116 and G121 in motif IV, A138 in motif V, and S182 in motif VI affect binding of both the double-stranded inosine-containing DNA substrate and the nicked double-stranded inosine-containing DNA product, resulting in multiple enzymatic turnovers. The substantially reduced DNA cleavage activity observed in G113 in motif IV and G136 in motif V can be partly attributed to their defect in metal cofactor coordination. Alanine substitution at amino acid 118 primarily reduces the level of binding to the nicked product, suggesting that R118 plays a significant role in postcleavage DNA-protein interaction. Binding and cleavage analyses of multiple mutants at positions Y80 and H116 underscore the role these residues play in protein-DNA interaction and implicate their potential involvement as a hydrogen bond donor in recognition of deaminated DNA bases. DNA cleavage analysis using mutants defective in DNA binding reveals a novel 3'-exonuclease activity in endonuclease V. An alternative model is proposed that entails lesion specific cleavage and endonuclease to 3'-exonuclease mode switch by endonuclease V for removal of deaminated base lesions during endonuclease V-mediated repair. PMID:16114885

Feng, Hong; Dong, Liang; Klutz, Athena M; Aghaebrahim, Nima; Cao, Weiguo

2005-08-30

384

Brazilein-induced contraction of rat arterial smooth muscle involves activation of Ca2+ entry and ROK, ERK pathways.  

PubMed

Brazilein (6a,7-dihydro-3,6a,10-trihydroxy-benz[b]indeno[1,2-d]pyran-9(6H)-one) is a compound isolated from Caesalpinia sappan. The vasoactivities of brazilein were evaluated in isolated rat thoracic aorta. The results showed that brazilein can dose-dependently induce contraction of rat thoracic aorta in the resting and phenylephrine pre-evoked state. The average response to 100 microM of brazilein was 30% of the 50 mM KCl contraction, 26% of the 10 muM phenylephrine and 116% of the 20 mM caffeine contraction in comparison. The effects of vasocontraction were proved not to be endothelial dependent and could not be inhibited by alpha-adrenergic receptor blocker phentolamine, beta-adrenergic receptor blocker propranolol, M-adrenaline receptor blocker atropine, angiotensin II receptor blocker losartan or the non-selective nitric oxide synthase (NOS) inhibitor NG-Nitro-L-Arginine Methyl Ester (L-NAME). However the influx of extracellular calcium seemed to be required for this action, because depletion of extracellular calcium and the addition of L-type calcium ion channel antagonist (nimodipine and diltiazem), calcium ion channel activator (BAY-K8644) and potassium ion channel opener (pinacidil) could significantly affect the contraction induced by brazilein. We also investigated the possible signal mechanisms underlying brazilein-induced contraction using selective inhibitors. The inhibitors of myosin light chain kinase (MLCK), Rho-kinase (ROK) and extracellular signal regulated kinase (ERK) can suppress the effect of brazilein respectively, whereas inhibitors of other signaling or receptor molecules such as protein kinase C (PKC) and inositol 1,4,5-triphosphate (IP3) receptor had no effect. All these results demonstrated that brazilein can induce contraction of rat aorta, that the Ca2+ influx, ROK and ERK signal pathways and MLCK activation must be involved in the contractile processes. PMID:18177858

Shen, Jia; Yip, Siewting; Wang, Zhixing; Wang, Wei; Xing, Dongming; Du, Lijun

2007-11-17

385

Fibroblast growth factors 7 and 10 are involved in ameloblastoma proliferation via the mitogen-activated protein kinase pathway.  

PubMed

Ameloblastoma is an epithelial benign tumor of the odontogenic apparatus and its growth mechanisms are not well understood. Fibroblast growth factor (FGF) 3, FGF7 and FGF10, which are expressed by the neural crest-derived ectomesenchymal cells, induce the proliferation of odontogenic epithelial cells during tooth development. Therefore, we examined the expression and function of these FGFs in ameloblastoma. We examined 32 cases of ameloblastoma as well as AM-1 cells (an ameloblastoma cell line) and studied the expression of FGF3, FGF7, FGF10 and their specific receptors, namely, FGF receptor (FGFR) 1 and FGFR2. Proliferation, mitogen-activated protein kinase (MAPK) signaling and PI3K signaling were examined in AM-1 cells after the addition of FGF7, FGF10 and these neutralizing antibodies. The expression of FGF7, FGF10, FGFR1 and FGFR2 was detected in ameloblastoma cells and AM-1 cells, while that of FGF3 was not. FGF7 and FGF10 stimulated AM-1 cell proliferation and phosphorylation of p44/42 MAPK. However, Akt was not phosphorylated. Blocking the p44/42 MAPK pathway by using a specific mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor (U0126) completely neutralized the effects of FGF7 and FGF10 on AM-1 cell proliferation. However, Anti FGF7 and FGF10 neutralizing antibodies did not decrease cell proliferation and MAPK phosphorylation of AM-1 cells. These results suggested that FGF7 and FGF10 are involved in the proliferation of ameloblastoma cells through the MAPK pathway. PMID:24002438

Nakao, Yu; Mitsuyasu, Takeshi; Kawano, Shintaro; Nakamura, Norifumi; Kanda, Shiori; Nakamura, Seiji

2013-08-29

386

Hippocampal dysfunction and cognitive impairments provoked by chronic early-life stress involve excessive activation of CRH receptors.  

PubMed

Chronic stress impairs learning and memory in humans and rodents and disrupts long-term potentiation (LTP) in animal models. These effects are associated with structural changes in hippocampal neurons, including reduced dendritic arborization. Unlike the generally reversible effects of chronic stress on adult rat hippocampus, we have previously found that the effects of early-life stress endure and worsen during adulthood, yet the mechanisms for these clinically important sequelae are poorly understood. Stress promotes secretion of the neuropeptide corticotropin-releasing hormone (CRH) from hippocampal interneurons, activating receptors (CRF(1)) located on pyramidal cell dendrites. Additionally, chronic CRF(1) occupancy negatively affects dendritic arborization in mouse organotypic slice cultures, similar to the pattern observed in middle-aged, early-stressed (CES) rats. Here we found that CRH expression is augmented in hippocampus of middle-aged CES rats, and then tested whether the morphological defects and poor memory performance in these animals involve excessive activation of CRF(1) receptors. Central or peripheral administration of a CRF(1) blocker following the stress period improved memory performance of CES rats in novel-object recognition tests and in the Morris water maze. Consonant with these effects, the antagonist also prevented dendritic atrophy and LTP attenuation in CA1 Schaffer collateral synapses. Together, these data suggest that persistently elevated hippocampal CRH-CRF(1) interaction contributes importantly to the structural and cognitive impairments associated with early-life stress. Reducing CRF(1) occupancy post hoc normalized hippocampal function during middle age, thus offering potential mechanism-based therapeutic interventions for children affected by chronic stress. PMID:20881118

Ivy, Autumn S; Rex, Christopher S; Chen, Yuncai; Dubé, Céline; Maras, Pamela M; Grigoriadis, Dimitri E; Gall, Christine M; Lynch, Gary; Baram, Tallie Z

2010-09-29

387

Hippocampal dysfunction and cognitive impairments provoked by chronic early-life stress involve excessive activation of CRH receptors  

PubMed Central

Chronic stress impairs learning and memory in humans and rodents and disrupts long-term potentiation (LTP) in animal models. These effects are associated with structural changes in hippocampal neurons, including reduced dendritic arborization. Unlike the generally reversible effects of chronic stress on adult rat hippocampus, we have previously found that the effects of early-life stress endure and worsen during adulthood, yet the mechanisms for these clinically important sequelae are poorly understood. Stress promotes secretion of the neuropeptide corticotropin-releasing hormone (CRH) from hippocampal interneurons, activating receptors (CRF1) located on pyramidal cell dendrites. Additionally, chronic CRF1 occupancy negatively affects dendritic arborization in mouse organotypic slice cultures, similar to the pattern observed in middle-aged, early-stressed (CES) rats. Here we found that CRH-expression is augmented in hippocampus of middle-aged CES rats, and then tested if the morphological defects and poor memory performance in these animals involve excessive activation of CRF1 receptors. Central or peripheral administration of a CRF1 blocker following the stress period improved memory performance of CES rats in novel object recognition tests and in the Morris water maze. Consonant with these effects, the antagonist also prevented dendritic atrophy and LTP attenuation in CA1 Schaffer collateral synapses. Together, these data suggest that persistently elevated hippocampal CRH-CRF1 interaction contributes importantly to the structural and cognitive impairments associated with early-life stress. Reducing CRF1 occupancy post-hoc normalized hippocampal function during middle-age, thus offering potential mechanism-based therapeutic interventions for children affected by chronic stress.

Ivy, Autumn S.; Rex, Christopher S.; Chen, Yuncai; Dube, Celine; Maras, Pamela M.; Grigoriadis, Dimitri E.; Gall, Christine M.; Lynch, Gary; Baram, Tallie Z.

2010-01-01

388

Involvement of the cysteine-rich head domain in activation and desensitization of the P2X1 receptor.  

PubMed

P2X receptors (P2XRs) are ligand-gated ion channels activated by extracellular ATP. Although the crystal structure of the zebrafish P2X4R has been solved, the exact mode of ATP binding and the conformational changes governing channel opening and desensitization remain unknown. Here, we used voltage clamp fluorometry to investigate movements in the cysteine-rich head domain of the rat P2X1R (A118-I125) that projects over the proposed ATP binding site. On substitution with cysteine residues, six of these residues (N120-I125) were specifically labeled by tetramethyl-rhodamine-maleimide and showed significant changes in the emission of the fluorescence probe on application of the agonists ATP and benzoyl-benzoyl-ATP. Mutants N120C and G123C showed fast fluorescence decreases with similar kinetics as the current increases. In contrast, mutants P121C and I125C showed slow fluorescence increases that seemed to correlate with the current decline during desensitization. Mutant E122C showed a slow fluorescence increase and fast decrease with ATP and benzoyl-benzoyl-ATP, respectively. Application of the competitive antagonist 2',3'-O-(2,4,6-trinitrophenyl)-ATP (TNP-ATP) resulted in large fluorescence changes with the N120C, E122C, and G123C mutants and minor or no changes with the other mutants. Likewise, TNP-ATP-induced changes in control mutants distant from the proposed ATP binding site were comparably small or absent. Combined with molecular modeling studies, our data confirm the proposed ATP binding site and provide evidence that ATP orients in its binding site with the ribose moiety facing the solution. We also conclude that P2XR activation and desensitization involve movements of the cysteine-rich head domain. PMID:22745172

Lörinczi, Éva; Bhargava, Yogesh; Marino, Stephen F; Taly, Antoine; Kaczmarek-Hájek, Karina; Barrantes-Freer, Alonso; Dutertre, Sébastien; Grutter, Thomas; Rettinger, Jürgen; Nicke, Annette

2012-06-27

389

Signals involved in T cell activation. II. Distinct roles of intact accessory cells, phorbol esters, and interleukin 1 in activation and cell cycle progression of resting T lymphocytes  

SciTech Connect

The signals involved in the initiation of mitogen-induced activation of resting guinea pig T cells were examined. The combination of phytohemagglutinin (PHA) and 4..beta..-phorbol 12-myristate 13-acetate (PMA) stimulated DNA synthesis by accessory cell (AC)-depleted T cells cultured at high density, but the use of low density cultures indicated that intact AC were absolutely necessary for PHA-stimulated T cell DNA synthesis even in the presence of PMA, interleukin 1 (IL 1), or interleukin 2 (IL 2). In contrast, AC-depleted T cells were able to respond to the combination of the calcium ionophore, ionomycin, and PMA regardless of the cell density at which they were cultured. Results of cell cycle analysis support the conclusion that intact AC, IL 1, and a PMA-like signal play distinct roles in the progression of mitogen stimulated T cells through the first round of the cell cycle.

Davis, L.; Lipsky, P.E.

1986-05-15

390

HIV-1 kills renal tubular epithelial cells in vitro by triggering an apoptotic pathway involving caspase activation and Fas upregulation.  

PubMed Central

HIV-infected patients suffer several renal syndromes, which can progress rapidly from renal insufficiency to end-stage renal disease. Histologically, HIV-induced nephropathy is characterized by prominent tubulopathy with apoptosis of tubular cells. Clinical and experimental evidence suggests that renal injury may be directly related to virus infection. Although HIV-1 is a polytropic and not solely lymphotropic pathogen, the susceptibility of renal cells to HIV-1 remains to be determined. This paper demonstrates in vitro the permissiveness of proximal tubular epithelial cells (PTEC) to HIV-1 and describes the effects of PTEC infection to explain the pathogenesis of tubular damage in vivo. The results indicate that PTEC express HIV-specific receptor and coreceptors and sustain virus replication. We observed that HIV-1 infection causes the death of tubular cells by triggering an apoptotic pathway involving caspase activation. Fas upregulation but not Fas ligand expression was found in the infected PTEC. However, after HIV-1 infection, tubular cells became susceptible to apoptosis induced through Fas stimulation. Caspase inhibition prevented the death of the infected PTEC in spite of persistent viral replication. These findings may explain the prominent histopathology of HIV-associated nephropathy and demonstrate that the apoptosis of nonlymphoid cells can be directly induced by HIV-1.

Conaldi, P G; Biancone, L; Bottelli, A; Wade-Evans, A; Racusen, L C; Boccellino, M; Orlandi, V; Serra, C; Camussi, G; Toniolo, A

1998-01-01

391

Paramagnetic 3d coordination complexes involving redox-active tetrathiafulvalene derivatives: an efficient approach to elaborate multi-properties materials.  

PubMed

The elaboration of multifunctional materials is a great challenge for the physical chemistry community and the studies of molecular materials exhibiting coexistence or synergy between two or more properties are very active. In particular, molecular compounds displaying electrical conductivity and magnetic interactions are currently the subject of intensive studies. Two approaches are now well-known and are explored. On the one hand, the interactions between mobile electrons of the organic network (? electrons) and localized electrons of paramagnetic transition metal (d electrons) take place through space. On the other hand, these interactions take place through covalent chemical bonds. In the latter, the probability to have significant interaction between ? and d electrons is enhanced compared to the first approach. In this perspective article, we will give an overview of the known coordination complexes involving tetrathiafulvalene derivatives as ligands for paramagnetic 3d ions and we will describe their physical properties. If necessary, the coexistence or synergy between electrical conductivity, magnetism and other properties will be highlighted. PMID:23208602

Pointillart, Fabrice; Golhen, Stéphane; Cador, Olivier; Ouahab, Lahcčne

2013-02-14

392

Activation of Ntf4, a Tobacco Mitogen-Activated Protein Kinase, during Plant Defense Response and Its Involvement in Hypersensitive Response-Like Cell Death1  

PubMed Central

Mitogen-activated protein kinase (MAPK) cascades are important signaling modules in eukaryotic cells. They function downstream of sensors/receptors and regulate cellular responses to external and endogenous stimuli. Recent studies demonstrated that SIPK and WIPK, two tobacco (Nicotiana spp.) MAPKs, are involved in signaling plant defense responses to various pathogens. Ntf4, another tobacco MAPK that shares 93.6% and 72.3% identity with SIPK and WIPK, respectively, was reported to be developmentally regulated and function in pollen germination. We found that Ntf4 is also expressed in leaves and suspension-cultured cells. Genomic analysis excluded the possibility that Ntf4 and SIPK are orthologs from the two parental lines of the amphidiploid common tobacco. In vitro and in vivo phosphorylation and activation assays revealed that Ntf4 shares the same upstream MAPK kinase, NtMEK2, with SIPK and WIPK. Similar to SIPK and WIPK, Ntf4 is also stress responsive and can be activated by cryptogein, a proteinaceous elicitin from oomycetic pathogen Phytophthora cryptogea. Tobacco recognition of cryptogein induces rapid hypersensitive response (HR) cell death in tobacco. Transgenic Ntf4 plants with elevated levels of Ntf4 protein showed accelerated HR cell death when treated with cryptogein. In addition, conditional overexpression of Ntf4, which results in high cellular Ntf4 activity, is sufficient to induce HR-like cell death. Based on these results, we concluded that Ntf4 is multifunctional. In addition to its role in pollen germination, Ntf4 is also a component downstream of NtMEK2 in the MAPK cascade that regulates pathogen-induced HR cell death in tobacco.

Ren, Dongtao; Yang, Kwang-Yeol; Li, Guo-Jing; Liu, Yidong; Zhang, Shuqun

2006-01-01

393

NKp44, A Triggering Receptor Involved in Tumor Cell Lysis by Activated Human Natural Killer Cells, Is a Novel Member of the Immunoglobulin Superfamily  

Microsoft Academic Search

Summary Surface receptors involved in natural killer (NK) cell triggering during the process of tumor cell lysis have recently been identified. Of these receptors, NKp44 is selectively expressed by IL-2- activated NK cells and may contribute to the increased efficiency of activated NK cells to me- diate tumor cell lysis. Here we describe the molecular cloning of NKp44. Analysis of

Claudia Cantoni; Cristina Bottino; Massimo Vitale; Anna Pessino; Raffaella Augugliaro; Angela Malaspina; Silvia Parolini; Lorenzo Moretta; Alessandro Moretta; Roberto Biassoni

2010-01-01

394

Normal Activity of Metabolic Pathways Involved in the Formation and Utilization of Phosphoribosylpyrophosphate in Erythrocytes of Patients with Primary Metabolic Gout  

Microsoft Academic Search

The activity of metabolic pathways involved in the formation and utilization of phosphoribosylpyrophosphate (PRPP) was studied in the erythrocytes of 34 patients with idiopathic metabolic gout. The activities of the oxidative pentose shunt, of the hypoxanthine-guanine and adenine phosphoribosyltransferases (HGPRT, APRT) and of PRPP synthetase, as well as the rates of PRPP generation and of adenine incorporation into nucleotides were

O. Sperling; Pnina Boer; Sara Brosh; Ella Elazar; A. Szeinberg; A. de Vries

1975-01-01

395

Lysophosphatidylcholine Activates p38 and p42\\/44 Mitogen-Activated Protein Kinases in Monocytic THP1 Cells, but Only p38 Activation Is Involved in Its Stimulated Chemotaxis  

Microsoft Academic Search

Oxidized LDLs (OxLDLs) have been shown to be involved in recruitment of blood monocytes into the arterial subendothelial space, which is the earliest step in atherogenesis, but the underlying molecular mechanisms are poorly understood. The present study demonstrated that lysophosphatidylcholine (LPC), a major phospholipid component of OxLDL, strongly evoked phosphorylation and activation of p38 and p42\\/44 mitogen-activated protein kinases in

Qing Jing; Sun-Mei Xin; Wen-Bo Zhang; Ping Wang; Yong-Wen Qin; Gang Pei

2000-01-01

396

Nonconventional involvement of LysRS in the molecular mechanism of USF2 transcriptional activity in FcepsilonRI-activated mast cells.  

PubMed

Reports of the biological multifunctional activity of various aminoacyl tRNA synthetases have recently accumulated in the literature. The primary function of these critical enzymes is to charge various tRNAs with their appropriate amino acids, thus producing the building blocks of protein synthesis. We have previously shown that lysyl tRNA synthetase (LysRS) associates with microphthalmia transcription factor (MITF) and regulates its activity by synthesis of Ap(4)A in mast cells. Here, we s