Long-term cerebral plasticity-related gene expression : a study of the respective role of CBP and CRTC1 in CREB transcriptional activation

1.1 AbstractThe treatment of memory disorders and cognitive deficits in various forms of mental retardation may greatly benefit from a better understanding of the molecular and cellular mechanisms of memory formation. Different forms of memory have distinct molecular requirements.Short-term memory (STM) is thought to be mediated by covalent modifications of existing synaptic molecules, such as phosphorylation or dephosphorylation of enzymes, receptors or ion channels. In contrast, long-term memoiy (LTM) is thought to be mediated by growth of new synapses and restructuring of existing synapses. There is extensive evidence that changes in gene expression and de novo protein synthesis are key processes for LTM formation. In this context, the transcription factor CREB (cAMP-response element-binding protein) was shown to be crucial. Activation of CREB requires phosphorylation of a serine residue (Ser-133), and the subsequent recruitment of a coactivator called CREB-binding protein (CBP). Moreover, we have recently shown that another coactivator called CREB Regulated Transcription Coactivator 1 (CRTC1) functions as a calcium- and cAMP-sensitive coincidence detector in neurons, and is involved in hippocampal long-term synaptic plasticity. Given the importance of cAMP and calcium signaling for plasticity-related gene expression in neurons and in astrocytes, we sought to determine the respective involvement of the CREB coactivators CBP and CRTC1 in CREB-mediated transcription.We developed various strategies to selectively interfere with these CREB coactivators in mouse primary neurons and in astrocytes in vitro. However, despite several pieces of evidence implicating CBP and/or CRTC1 in the regulation of neuronal plasticity genes, we could not clearly determine the respective requirement of these coactivators for the activation of these genes. Nevertheless, we showed that calcineurin activity, which is important for CRTC1 nuclear translocation, is necessary for the expression of some CREB-regulated plasticity genes. We associated this phenomena to physiopathological conditions observed in Down's syndrome. In addition, we demonstrated that in astrocytes, noradrenaline stimulates CREB-target gene expression through β-adrenergic receptor activation, intracellular cAMP pathway activation, and CRTC-induced CREB transactivation.Defining the respective role of CREB and its coactivators CBP and CRTC1 in neuronal and astrocytic cultures in vitro sets the stage for future in vivo studies and for the possible development of new therapeutic strategies to improve the treatment of memoiy and cognitive disorders.1.2 RésuméUne meilleure connaissance des mécanismes moléculaires et cellulaires responsables de la formation de la mémoire pourrait grandement améliorer le traitement des troubles de la mémoire ainsi que des déficits cognitifs observés dans différentes formes de pathologies psychiatriques telles que le retard mental. Les différentes formes de mémoire dépendent de processus moléculaires différents.La mémoire à court terme (STM) semble prendre forme suite à des modifications covalentes de molécules synaptiques préexistantes, telles que la phosphorylation ou la déphosphorylation d'enzymes, de récepteurs ou de canaux ioniques. En revanche, la mémoire à long terme (LTM) semble être due à la génération de nouvelles synapses et à la restructuration des synapses existantes. De nombreuses études ont permis de démontrer que les changements dans l'expression des gènes et la synthèse de protéine de novo sont des processus clés pour la formation de la LTM. Dans ce contexte, le facteur de transcription CREB (cAMP-response element-binding protein) s'est avéré être un élément crucial. L'activation de CREB nécessite la phosphorylation d'un résidu sérine (Ser-133), et le recrutement d'un coactivateur nommé CBP (CREB binding protein). En outre, nous avons récemment démontré qu'un autre coactivateur de CREB nommé CRTC1 (CREB Regulated Transcription Coactivator 1) agit comme un détecteur de coïncidence de l'AMP cyclique (AMPc) et du calcium dans les neurones et qu'il est impliqué dans la formation de la plasticité synaptique à long terme dans l'hippocampe. Etant donné l'importance des voies de l'AMPc et du calcium dans l'expression des gènes impliqués dans la plasticité cérébrale, nous voulions déterminer le rôle respectif des coactivateurs de CREB, CBP et CRTC1.Nous avons développé diverses stratégies pour interférer de façon sélective avec les coactivateurs de CREB dans les neurones et dans les astrocytes chez la souris in vitro. Nos résultats indiquent que CBP et CRTC1 sont tous deux impliqués dans la transcription dépendante de CREB induite par l'AMPc et le calcium dans les neurones. Cependant, malgré plusieurs évidences impliquant CBP et/ou CRTC1 dans l'expression de gènes de plasticité neuronale, nous n'avons pas pu déterminer clairement leur nécessité respective pour l'activation de ces gènes. Toutefois, nous avons montré que l'activité de la calcineurine, dont dépend la translocation nucléaire de CRTC1, est nécessaire à l'expression de certains de ces gènes. Nous avons pu associer ce phénomène à une condition physiopathologique observée dans le syndrome de Down. Nous avons également montré que dans les astrocytes, la noradrénaline stimule l'expression de gènes cibles de CREB par une activation des récepteurs β- adrénergiques, l'activation de la voie de l'AMPc et la transactivation de CREB par les CRTCs.Définir le rôle respectif de CREB et de ses coactivateurs CBP et CRTC1 dans les neurones et dans les astrocytes in vitro permettra d'acquérir les connaissances nécessaires à de futures études in vivo et, à plus long terme d'éventuellement développer des stratégies thérapeutiques pour améliorer les traitements des troubles cognitifs.

Early change in defence mechanisms and coping in short-term dynamic psychotherapy: relations with symptoms and alliance.

Several patient-related variables have already been investigated as predictors of change in psychodynamic psychotherapy. Defensive functioning is one of them. However, few studies have investigated adaptational processes, encompassing defence mechanisms and coping, from an integrative or comparative viewpoint. This study includes 32 patients, mainly diagnosed with adjustment disorder and undergoing time-limited psychodynamic psychotherapy lasting up to 40 sessions, and will focus on early change in defence and coping. Observer-rater methodology was applied to the transcripts of two sessions of the first part of the psychotherapeutic process. It is assumed that the contextual-relational variable of therapeutic alliance intervenes as moderator on change in adaptational processes. Results corroborated the hypothesis, but only for coping, whereas for defences, overall functioning remained stable over the first 20 sessions of psychotherapy. These results are discussed within the framework of disentangling processes underlying adaptation, i.e., related to issues on trait and state aspects, as well as the role of the therapeutic alliance.

Short-term investment and equilibrium multiplicity

I study the effects of the heterogeneity of traders'horizon in the context of a 2-period NREE model whereall traders are risk averse. Owing to inventory effects,myopic trading behavior generates multiplicity ofequilibria. In particular, two distinct patterns arise.Along the first equilibrium, short term tradersanticipate higher second period price reaction toinformation arrival and, owing to risk aversion,scale back their trading intensity. This, in turn,reduces both risk sharing and information impoundinginto prices enforcing a high returns' volatility-lowprice informativeness equilibrium. In the second one,the opposite happens and a low volatility-high priceinformativeness equilibrium arises.

Why do emerging economies borrow short term?

We argue that one reason why emerging economies borrow short term is that it is cheaperthan borrowing long term. This is especially the case during crises, as in these episodes therelative cost of long-term borrowing increases. We construct a unique database of sovereignbond prices, returns, and issuances at di¤erent maturities for 11 emerging economies from 1990to 2009 and present a set of new stylized facts. On average, these countries pay a higher riskpremium on long-term than on short-term bonds. During crises, the di¤erence between the tworisk premia increases and issuance shifts towards shorter maturities. To illustrate our argument,we present a simple model in which the maturity structure is the outcome of a risk sharingproblem between an emerging economy subject to rollover crises and risk averse internationalinvestors.

Short term variation in the vertical distribution of copepods off the coast of northern Peru

Analiza los datos colectados de la clorofila frente al Peru cerca de 9°S. Determinandose la profundidad a la que se enuentran y la concentración de oxigeno durante el dia y la noche.

Impact of personality on termination of short-term group psychotherapy in depressed elderly outpatients

Objective Termination in group psychotherapy is an essential phase of the psychotherapeutic process, yet its clinical determinants remain largely unknown, especially in elderly patients. The aim of this study was to assess how patients' personality traits influence their way of leaving a short-term psychotherapy group as well as a larger therapeutic community program. <p>Method Personality traits were assessed with the NEO Five-Factor Inventory in 24 elderly depressed outpatients. Patients' terminations from the group as well as from the community were ranked into four classes according to their appropriateness (completeness of experience and ability to deal with feelings of separation). Results Neuroticism was not related to the quality of termination. In contrast, agreeableness and openness to experience were strongly associated with successful termination. Conscientiousness and extraversion may have a differential impact depending on the type of group (group psychotherapy versus therapeutic community). Conclusion Personality traits may be important clinical determinants of the quality of termination process in both group psychotherapy and therapeutic community settings for elderly depressed patients.

Experimental manipulation of colony genetic diversity had no effect on short-term task efficiency in the Argentine ant Linepithema humile

Genetic diversity might increase the performance of social groups by improving task efficiency or disease resistance, but direct experimental tests of these hypotheses are rare. We manipulated the level of genetic diversity in colonies of the Argentine ant Linepithema humile, and then recorded the short-term task efficiency of these experimental colonies. The efficiency of low and high genetic diversity colonies did not differ significantly for any of the following tasks: exploring a new territory, foraging, moving to a new nest site, or removing corpses. The tests were powerful enough to detect large effects, but may have failed to detect small differences. Indeed, observed effect sizes were generally small, except for the time to create a trail during nest emigration. In addition, genetic diversity had no statistically significant impact on the number of workers, males and females produced by the colony, but these tests had low power. Higher genetic diversity also did not result in lower variance in task efficiency and productivity. In contrast to genetic diversity, colony size was positively correlated with the efficiency at performing most tasks and with colony productivity. Altogether, these results suggest that genetic diversity does not strongly improve short-term task efficiency in L. humile, but that worker number is a key factor determining the success of this invasive species.

Short-term moderate hypocapnia augments detection of optimal cerebral perfusion pressure.

An autoregulation-oriented strategy has been proposed to guide neurocritical therapy toward the optimal cerebral perfusion pressure (CPPOPT). The influence of ventilation changes is, however, unclear. We sought to find out whether short-term moderate hypocapnia (HC) shifts the CPPOPT or affects its detection. Thirty patients with traumatic brain injury (TBI), who required sedation and mechanical ventilation, were studied during 20 min of normocapnia (5.1±0.4 kPa) and 30 min of moderate HC (4.4±3.0 kPa). Monitoring included bilateral transcranial Doppler of the middle cerebral arteries (MCA), invasive arterial blood pressure (ABP), and intracranial pressure (ICP). Mx -autoregulatory index provided a measure for the CPP responsiveness of MCA flow velocity. CPPOPT was assessed as the CPP at which autoregulation (Mx) was working with the maximal efficiency. During normocapnia, CPPOPT (left: 80.65±6.18; right: 79.11±5.84 mm Hg) was detectable in 12 of 30 patients. Moderate HC did not shift this CPPOPT but enabled its detection in another 17 patients (CPPOPT left: 83.94±14.82; right: 85.28±14.73 mm Hg). The detection of CPPOPT was achieved via significantly improved Mx-autoregulatory index and an increase of CPP mean. It appeared that short-term moderate HC augmented the detection of an optimum CPP, and may therefore usefully support CPP-guided therapy in patients with TBI.

Comparative short-term response and remission rates for tacrolimus, cyclosporine, and infliximab for steroid-refractory ulcerative colitis

BACKGROUND: Calcineurin inhibitors (cyclosporine (CsA) and tacrolimus (Tcl)) and the anti-TNF-antibody infliximab (IFX) are established therapeutic options in steroid-refractory ulcerative colitis (UC). In acute severe UC failing steroids, a randomized trial showed an 85% short term response to CsA or IFX, with avoidance of colectomy. Comparative responses to the three drugs in outpatients with steroid-refractory UC are unknown. METHOD: Response to treatment in patients with steroid-refractory moderate to severe UC was retrospectively studied in three cohorts of patients: Cohort A (n=24) treated with oral Tcl (initially 0.05mg/kg twice daily, aiming for serum trough levels of 5-10 ng/mL); Cohort B (n=19) treated with intravenous CsA 2mg/kg/daily and then oral CsA 5mg/kg/daily; Cohort C. (n= 41) treated with IFX (5mg/kg intravenously at week 0, 2, 6 and then every 8 weeks). After successful rescue therapy with Tcl or CsA, thiopurine maintenance therapy was introduced. The endpoint was evaluation of clinical remission or response at week 6, on the basis of modified Truelove-Witts severity index (MTWSI). RESULTS: After 6 weeks, 42% (10/24) of patients treated with Tcl achieved remission (MTWSI score ≤4) compared to 47% (9/ 19) on CsA and 66% (27/41) of patients treated with IFX (Tcl & CsA vs IFX p=0.127). Clinical response (decrease of MTWSI score of more than 4 points) at week 6 was reached in 25% (6/24) patients on Tcl, compared to 11% (2/19) on CsA and 20% (8/41) given IFX (p=0.484). Subgroup analysis showed the highest rates of remission in those with moderate steroid-refractory UC treated with IFX: 29% (2/7) in Tcl group compared to 50% (2/4) in CsA group and 76 % (19/25) in IFX group (Tcl &CsA vs IFX p= 0.058) Patients with severe colitis showed similar rates of remission in all three groups: 47% (8/17) on Tcl, 47% (7/ 15) on CsA and 50% (8/16) on IFX (p= 0.700). Colectomy within 6 weeks occurred in 4% (1/24) after Tcl, 5% (1/19) after CsA and 0% (0/41) after IFX. Adverse effects in the first 6 weeks were observed in 13% (3/24) on Tcl, 26% (5/19) on CsA, and 10% (4/41) on IFX (p=0.224) CONCLUSION: No significant differences in response, remission, colectomy rate or adverse events between the three agents were found, although the study is too small for definitive conclusions. There are intriguing differences, with potentially greater response to IFX in moderate, steroid-refractory UC.

Generation of short-term murine natural killer cell clones to analyze Ly49 gene expression.

Natural killer (NK) cellsexpress receptors specific for class I major histocompatibility complex (MHC) molecules. In the mouse, the class I specific receptors identified to date belong to the polymorphic Ly49 receptor family. Engagement of Ly49 receptors with their respective MHC ligands results in negative regulation of NK cell effector functions, consistent with a critical role of these receptors in "missing self" recognition. The Ly49 receptors analyzed so far are clonally distributed such that multiple distinct Ly49 receptors can be expressed by individual NK cells (for review see refs. 1-3). The finding that most NK cells that express the Ly49A receptor do so from a single Ly49A allele (whereby expression can occur from the maternal or the paternal chromosome) may thus reflect a putative receptor distribution process that restricts the number of Ly49 receptors expressed in a single NK cell (3-5).

Nestling barn owls assess short-term variation in the amount of vocally competing siblings.

Assessing the amount of rivals is crucial to optimally adjust investment into a contest. If laboratory animals show numerical abilities, little is known about the ecological implications particularly in young animals. The two to nine barn owl (Tyto alba) siblings vocally compete for priority of access to food resources before parents actually deliver them. In dyads, the individual that vocalizes at the highest rate in the absence of parents deters its siblings from competing for next delivered prey. We tested the novel hypothesis that to optimally adjust vocal investment, barn owl nestlings assess how many of their siblings are currently competing. To singleton owlets, we broadcasted a fixed global number of calls emitted by one, two or four pre-recorded unfamiliar nestlings. We could thus distinguish the independent effect on singletons' vocal behavior of the global number of calls produced by a brood from the number of competitors that produced these calls. Overall, nestlings retreated more from vocal contest when facing more competitors. However, in front of one highly motivated competitor, nestlings refrained from vocalizing to a larger extent than when competing against more but less motivated individuals. Therefore, young animals assess variation in the number of currently competing siblings based on individual-specific vocal cues.

One minute of grief: Emotional processing in short-term dynamic psychotherapy for adjustment disorder.

OBJECTIVE: Depth of emotional processing has shown to be related to outcome across approaches to psychotherapy. Moreover, a specific emotional sequence has been postulated and tested in several studies on experiential psychotherapy (Pascual-Leone & Greenberg, 2007). This process-outcome study aims at reproducing the sequential model of emotional processing in psychodynamic psychotherapy for adjustment disorder and linking these variables with ultimate therapeutic outcome. METHOD: In this study, 32 patients underwent short-term dynamic psychotherapy. On the basis of reliable clinical change statistics, a subgroup (n = 16) presented with good outcome and another subgroup (n = 16) had a poor outcome in the end of treatment. The strongest alliance session of each case was rated using the observer-rated system Classification of Affective Meaning States. Reliability coefficients for the measure were excellent (κ = .82). RESULTS: Using 1 min as the fine-grained unit of analysis, results showed that the experience of fundamentally adaptive grief was more common in the in-session process of patients with good outcome, compared with those with poor outcomes (χ2 = 6.56, p = .01, d = 1.23). This variable alone predicted 19% of the change in depressive symptoms as measured by the Beck Depression Inventory at the end of treatment. Moreover, sequences of the original model were supported and related to outcome. CONCLUSIONS: These results are discussed within the framework of the sequential model of emotional processing and its possible relevance for psychodynamic psychotherapy. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Short-term and sustained renal effects of angiotensin II receptor blockade in healthy subjects.

We investigated the short-term and sustained hormonal and renal effects of angiotensin II (Ang II) receptor blockade in normotensive healthy volunteers. Twenty-four subjects maintained on a fixed sodium diet were randomized to receive for 8 days a placebo or 10 or 50 mg doses of the Ang II antagonist irbesartan (SR 47436, BMS 186295) according to a double-blind, parallel group design. Plasma renin activity, plasma immunoreactive Ang II and aldosterone levels, blood pressure, renal hemodynamics, and urinary electrolyte excretion were measured for 8 hours after the first and eighth administration of each dose of irbesartan or placebo. Ang II receptor blockade with irbesartan induced a dose-dependent compensatory increase in plasma renin activity and plasma angiotensin levels and a significant decrease in plasma aldosterone levels. The compensatory rise in plasma renin activity and Ang II levels was more pronounced on day 8, reflecting a long duration of the blocking effect of irbesartan. Irbesartan induced small changes in blood pressure and did not significantly modify renal blood flow and glomerular filtration rate. However, a significant decrease in filtration fraction was observed during receptor blockade on days 1 and 8. The tubular effects of irbesartan were characterized by a dose-dependent increase in sodium and chloride excretions. Interestingly, the cumulative natriuretic response to Ang II receptor blockade was similar on days 1 and 8, suggesting that in these subjects, renal Ang II receptors are not blocked over 24 hours during repeated administration even though this antagonist has a long duration of action (t1/2 of 15 to 17 hours).(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term effects of prescribed burning on wood-rotting fungi

Summary