Paying less but harvesting more: the effect of unconscious acceptance in regulating frustrating emotion.

PubMed

Ding, NanXiang; Yang, JieMin; Liu, YingYing; Yuan, JiaJin

2015-08-01

Previous studies indicate that emotion regulation may occur unconsciously, without the cost of cognitive effort, while conscious acceptance may enhance negative experiences despite having potential long-term health benefits. Thus, it is important to overcome this weakness to boost the efficacy of the acceptance strategy in negative emotion regulation. As unconscious regulation occurs with little cost of cognitive resources, the current study hypothesizes that unconscious acceptance regulates the emotional consequence of negative events more effectively than does conscious acceptance. Subjects were randomly assigned to conscious acceptance, unconscious acceptance and no-regulation conditions. A frustrating arithmetic task was used to induce negative emotion. Emotional experiences were assessed on the Positive Affect and Negative Affect Scale while emotion- related physiological activation was assessed by heart-rate reactivity. Results showed that conscious acceptance had a significant negative affective consequence, which was absent during unconscious acceptance. That is, unconscious acceptance was linked with little reduction of positive affect during the experience of frustration, while this reduction was prominent in the control and conscious acceptance groups. Instructed, conscious acceptance resulted in a greater reduction of positive affect than found for the control group. In addition, both conscious and unconscious acceptance strategies significantly decreased emotion-related heart-rate activity (to a similar extent) in comparison with the control condition. Moreover, heart-rate reactivity was positively correlated with negative affect and negatively correlated with positive affect during the frustration phase relative to the baseline phase, in both the control and unconscious acceptance groups. Thus, unconscious acceptance not only reduces emotion-related physiological activity but also better protects mood stability compared with conscious acceptance. This suggests that the clinical practice of acceptance therapy may need to consider using the unconscious priming of an accepting attitude, instead of intentionally instructing people to implement such a strategy, to boost the efficacy of acceptance in emotion regulation.

Mechanisms of ErbB receptor negative regulation and relevance in cancer

PubMed Central

Fry, William H.D.; Kotelawala, Lakmal; Sweeney, Colleen; Carraway, Kermit L.

2009-01-01

The ErbB family of receptor tyrosine kinases engages a wide variety of signaling pathways that collectively direct transcriptional programs controlling organogenesis during development and tissue maintenance in the adult. These receptors are also frequently found overexpressed or aberrantly activated in various cancers, suggesting that ErbB receptor signaling activity must be very tightly regulated. Sufficient levels of ErbB signaling are necessary to mediate tissue homeostasis, for example, but over-signaling can trigger cellular processes that contribute to cancer initiation or progression. Efforts over the last quarter century have led to a thorough understanding of the signaling pathways that are activated by these receptors and the mechanisms by which ErbB receptors engage these pathways. However, the compensatory negative regulatory mechanisms responsible for attenuating receptor activation have only more recently begun to be explored. Here we review the different known mechanisms of ErbB negative regulation, with particular emphasis on those proteins that exhibit some specificity for the ErbB family. We also describe how loss or suppression of ErbB negative regulators may contribute to tumor development, and discuss how restoration or augmentation of these pathways may represent a novel avenue for the development of ErbB-targeted therapies. PMID:18706412

Neural Correlates of Automatic Mood Regulation in Girls at High Risk for Depression

PubMed Central

Joormann, Jutta; Cooney, Rebecca E.; Henry, Melissa L.; Gotlib, Ian H.

2012-01-01

Daughters of depressed mothers are at significantly elevated risk for developing a depressive disorder themselves. We have little understanding, however, of the specific factors that contribute to this risk. The ability to regulate negative affect effectively is critical to emotional and physical health and may play an important role in influencing risk for depression. We examined whether never-disordered daughters whose mothers have experienced recurrent episodes of depression during their daughters’ lifetime differ from never-disordered daughters of never-disordered mothers in their patterns of neural activation during a negative mood induction and during automatic mood regulation. Sad mood was induced in daughters through the use of film clips; daughters then recalled positive autobiographical memories, a procedure shown previously to repair negative affect. During the mood induction, high-risk girls exhibited greater activation than did low-risk daughters in brain areas that have frequently been implicated in the experience of negative affect, including the amygdala and ventrolateral prefrontal cortex. In contrast, during automatic mood regulation, low-risk daughters exhibited greater activation than did their high-risk counterparts in brain areas that have frequently been associated with top-down regulation of emotion, including the dorsolateral prefrontal cortex and dorsal anterior cingulate cortex. These findings indicate that girls at high and low risk for depression differ in their patterns of neural activation both while experiencing, and while repairing negative affect, and suggest that anomalies in neural functioning precede the onset of a depressive episode. PMID:21895344

β-Arrestins Negatively Regulate the Toll Pathway in Shrimp by Preventing Dorsal Translocation and Inhibiting Dorsal Transcriptional Activity*

PubMed Central

Sun, Jie-Jie; Lan, Jiang-Feng; Shi, Xiu-Zhen; Yang, Ming-Chong; Niu, Guo-Juan; Ding, Ding; Zhao, Xiao-Fan; Yu, Xiao-Qiang; Wang, Jin-Xing

2016-01-01

The Toll signaling pathway plays an important role in the innate immunity of Drosophila melanogaster and mammals. The activation and termination of Toll signaling are finely regulated in these animals. Although the primary components of the Toll pathway were identified in shrimp, the functions and regulation of the pathway are seldom studied. We first demonstrated that the Toll signaling pathway plays a central role in host defense against Staphylococcus aureus by regulating expression of antimicrobial peptides in shrimp. We then found that β-arrestins negatively regulate Toll signaling in two different ways. β-Arrestins interact with the C-terminal PEST domain of Cactus through the arrestin-N domain, and Cactus interacts with the RHD domain of Dorsal via the ankyrin repeats domain, forming a heterotrimeric complex of β-arrestin·Cactus·Dorsal, with Cactus as the bridge. This complex prevents Cactus phosphorylation and degradation, as well as Dorsal translocation into the nucleus, thus inhibiting activation of the Toll signaling pathway. β-Arrestins also interact with non-phosphorylated ERK (extracellular signal-regulated protein kinase) through the arrestin-C domain to inhibit ERK phosphorylation, which affects Dorsal translocation into the nucleus and phosphorylation of Dorsal at Ser276 that impairs Dorsal transcriptional activity. Our study suggests that β-arrestins negatively regulate the Toll signaling pathway by preventing Dorsal translocation and inhibiting Dorsal phosphorylation and transcriptional activity. PMID:26846853

Smurf2 negatively modulates RIG-I-dependent antiviral response by targeting VISA/MAVS for ubiquitination and degradation.

PubMed

Pan, Yu; Li, Rui; Meng, Jun-Ling; Mao, He-Ting; Zhang, Yu; Zhang, Jun

2014-05-15

VISA (also known as MAVS, Cardif, IPS-1) is the essential adaptor protein for virus-induced activation of IFN regulatory factors 3 and 7 and production of type I IFNs. Understanding the regulatory mechanisms for VISA will provide detailed insights into the positive or negative regulation of innate immune responses. In this study, we identified Smad ubiquitin regulatory factor (Smurf) 2, one of the Smad ubiquitin regulator factor proteins, as an important negative regulator of virus-triggered type I IFN signaling, which targets at the VISA level. Overexpression of Smurf2 inhibits virus-induced IFN-β and IFN-stimulated response element activation. The E3 ligase defective mutant Smurf2/C716A loses the ability to suppress virus-induced type I IFN signaling, suggesting that the negative regulation is dependent on the ubiquitin E3 ligase activity of Smurf2. Further studies demonstrated that Smurf2 interacted with VISA and targeted VISA for K48-linked ubiquitination, which promoted the degradation of VISA. Consistently, knockout or knockdown of Smurf2 expression therefore promoted antiviral signaling, which was correlated with the increase in protein stability of VISA. Our findings suggest that Smurf2 is an important nonredundant negative regulator of virus-triggered type I IFN signaling by targeting VISA for K48-linked ubiquitination and degradation.

GATA4 negatively regulates bone sialoprotein expression in osteoblasts.

PubMed

Song, Insun; Jeong, Byung-Chul; Choi, Yong Jun; Chung, Yoon-Sok; Kim, Nacksung

2016-06-01

GATA4 has been reported to act as a negative regulator in osteoblast differentiation by inhibiting the Dlx5 transactivation of Runx2 via the attenuation of the binding ability of Dlx5 to the Runx2 promoter region. Here, we determine the role of GATA4 in the regulation of bone sialoprotein (Bsp) in osteoblasts. We observed that the overexpression of Runx2 or Sox9 induced the Bsp expression in osteoblastic cells. Silencing GATA4 further enhanced the Runx2- and Sox9-mediated Bsp promoter activity, whereas GATA4 overexpression down-regulated Bsp promoter activity mediated by Runx2 and Sox9. GATA4 also interacted with Runx2 and Sox9, by attenuating the binding ability of Runx2 and Sox9 to the Bsp promoter region. Our data suggest that GATA4 acts as a negative regulator of Bsp expression in osteoblasts. [BMB Reports 2016; 49(6): 343-348].

Neurons for hunger and thirst transmit a negative-valence teaching signal.

PubMed

Betley, J Nicholas; Xu, Shengjin; Cao, Zhen Fang Huang; Gong, Rong; Magnus, Christopher J; Yu, Yang; Sternson, Scott M

2015-05-14

Homeostasis is a biological principle for regulation of essential physiological parameters within a set range. Behavioural responses due to deviation from homeostasis are critical for survival, but motivational processes engaged by physiological need states are incompletely understood. We examined motivational characteristics of two separate neuron populations that regulate energy and fluid homeostasis by using cell-type-specific activity manipulations in mice. We found that starvation-sensitive AGRP neurons exhibit properties consistent with a negative-valence teaching signal. Mice avoided activation of AGRP neurons, indicating that AGRP neuron activity has negative valence. AGRP neuron inhibition conditioned preference for flavours and places. Correspondingly, deep-brain calcium imaging revealed that AGRP neuron activity rapidly reduced in response to food-related cues. Complementary experiments activating thirst-promoting neurons also conditioned avoidance. Therefore, these need-sensing neurons condition preference for environmental cues associated with nutrient or water ingestion, which is learned through reduction of negative-valence signals during restoration of homeostasis.

Neural Bases of Social Anxiety Disorder: Emotional Reactivity and Cognitive Regulation During Social and Physical Threat

PubMed Central

Goldin, Philippe R.; Manber, Tali; Hakimi, Shabnam; Canli, Turhan; Gross, James J.

2014-01-01

Context Social anxiety disorder is thought to involve emotional hyper-reactivity, cognitive distortions, and ineffective emotion regulation. While the neural bases of emotional reactivity to social stimuli have been described, the neural bases of emotional reactivity and cognitive regulation during social and physical threat, and their relationship to social anxiety symptom severity, have yet to be investigated. Objective This study investigated behavioral and neural correlates of emotional reactivity and cognitive regulation in patients and controls during processing of social and physical threat stimuli. Design Participants were trained to implement cognitive-linguistic regulation of emotional reactivity induced by social (harsh facial expressions) and physical (violent scenes) threat while undergoing functional magnetic resonance imaging and providing behavioral ratings of negative emotion experience. Setting Academic psychology department. Participants 15 adults with social anxiety disorder and 17 demographically-matched healthy controls. Main Outcome Measures Blood oxygen level dependent signal and negative emotion ratings. Results Behaviorally, patients reported greater negative emotion than controls during social and physical threat, but showed equivalent reduction in negative emotion following cognitive regulation. Neurally, viewing social threat resulted in greater emotion-related neural responses in patients than controls, with social anxiety symptom severity related to activity in a network of emotion and attention processing regions in patients only. Viewing physical threat produced no between-group differences. Regulation during social threat resulted in greater cognitive and attention regulation-related brain activation in controls compared to patients. Regulation during physical threat produced greater cognitive control-related response (i.e., right DLPFC) in patients compared to controls. Conclusions Compared to controls, patients demonstrated exaggerated negative emotion reactivity and reduced cognitive regulation related neural activation, specifically for social threat stimuli. These findings help to elucidate potential neural mechanisms of emotion regulation that might serve as biomarkers for interventions for social anxiety disorder. PMID:19188539

Defective interleukin-4/Stat6 activity correlates with increased constitutive expression of negative regulators SOCS-3, SOCS-7, and CISH in colon cancer cells.

PubMed

Liu, Xiao Hong; Xu, Shuang Bing; Yuan, Jia; Li, Ben Hui; Zhang, Yan; Yuan, Qin; Li, Pin Dong; Li, Feng; Zhang, Wen Jie

2009-12-01

Interleukin-4 (IL-4)-induced Stat6 activities (phenotypes) vary among human cancer cells, of which the HT-29 cell line carries an active Stat6(high) phenotype, while Caco-2 carries a defective Stat6(null) phenotype, respectively. Cancer cells with Stat6(high) show resistance to apoptosis and exaggerated metastasis, suggesting the clinical significance of Stat6 phenotypes. We previously showed that Stat6(high) HT-29 cells exhibited low constitutive expression of Stat6-negative regulators SOCS-1 and SHP-1 because of gene hypermethylation. This study further examined the constitutive expression of other closely related SOCS family numbers including SOCS-3, SOCS-5, SOCS-7, and CISH using RT-PCR. Similar to SOCS-1 and SHP-1, Stat6(high) HT-29 cells expressed low constitutive mRNA of SOCS-3, SOCS-7, and CISH than Stat6(null) Caco-2 cells. Interestingly, DNA demethylation using 5-aza-2'-deoxycytidine in HT-29 cells up-regulated mRNA expression of the above genes, indicating a hypermethylation status, which was confirmed by methylation-specific sequencing in selected SOCS-3 gene. Furthermore, defective Stat6(null) Caco-2 exhibited impaired phosphorylation of Stat6 after IL-4 stimulation by flow cytometry, in keeping with the notion of an over-performed negative regulation. The findings that IL-4/Stat6 phenotypes show differential expression of multiple negative regulators suggest a model that a collective force of powerful negative regulators, directly and indirectly, acts on Stat6 activation, which may result in differential Stat6 phenotypes.

Phosphorylation of Trihelix Transcriptional Repressor ASR3 by MAP KINASE4 Negatively Regulates Arabidopsis Immunity

PubMed Central

Li, Bo; Jiang, Shan; Yu, Xiao; Cheng, Cheng; Chen, Sixue; Cheng, Yanbing; Yuan, Joshua S.; Jiang, Daohong; He, Ping; Shan, Libo

2015-01-01

Proper control of immune-related gene expression is crucial for the host to launch an effective defense response. Perception of microbe-associated molecular patterns (MAMPs) induces rapid and profound transcriptional reprogramming via unclear mechanisms. Here, we show that ASR3 (ARABIDOPSIS SH4-RELATED3) functions as a transcriptional repressor and plays a negative role in regulating pattern-triggered immunity (PTI) in Arabidopsis thaliana. ASR3 belongs to a plant-specific trihelix transcription factor family for which functional studies are lacking. MAMP treatments induce rapid phosphorylation of ASR3 at threonine 189 via MPK4, a mitogen-activated protein kinase that negatively regulates PTI responses downstream of multiple MAMP receptors. ASR3 possesses transcriptional repressor activity via its ERF-associated amphiphilic repression motifs and negatively regulates a large subset of flg22-induced genes. Phosphorylation of ASR3 by MPK4 enhances its DNA binding activity to suppress gene expression. Importantly, the asr3 mutant shows enhanced disease resistance to virulent bacterial pathogen infection, whereas transgenic plants overexpressing the wild-type or phospho-mimetic form of ASR3 exhibit compromised PTI responses. Our studies reveal a function of the trihelix transcription factors in plant innate immunity and provide evidence that ASR3 functions as a transcriptional repressor regulated by MAMP-activated MPK4 to fine-tune plant immune gene expression. PMID:25770109

Serotonin transporter genotype modulates cognitive reappraisal of negative emotions: a functional magnetic resonance imaging study

PubMed Central

Siep, Nicolette; Markus, C. Rob

2013-01-01

A functional polymorphism within the serotonin transporter gene (5-HTTLPR) has been reported to modulate emotionality and risk for affective disorders. The short (S) allele has less functional efficacy than the long (L) allele and has been associated with enhanced emotional reactivity. One possible contributing factor to the high emotionality in S carriers may be inefficient use of cognitive strategies such as reappraisal to regulate emotional responses. The aim of the present study was to test whether the 5-HTTLPR genotype modulates the neural correlates of emotion regulation. To determine neural differences between S and L allele carriers during reappraisal of negative emotions, 15 homozygous S (S′/S′) and 15 homozygous L (L′/L′) carriers underwent functional magnetic resonance imaging (fMRI), while performing an instructed emotion regulation task including downregulation, upregulation and passive viewing of negative emotional pictures. Compared to L′/L′ allele carriers, subjects who carry the S′/S′ allele responded with lower posterior insula and prefrontal brain activation during passive perception of negative emotional information but showed greater prefrontal activation and anterior insula activation during down- and upregulation of negative emotional responses. The current results support and extend previous findings of enhanced emotionality in S carriers by providing additional evidence of 5-HTTLPR modulation of volitional emotion regulation. PMID:22345383

Neural indicators of emotion regulation via acceptance vs reappraisal in remitted major depressive disorder

PubMed Central

Keng, Shian-Ling; Ji, Jie Lisa; Moore, Tyler; Minkel, Jared; Dichter, Gabriel S.

2015-01-01

Mood disorders are characterized by impaired emotion regulation abilities, reflected in alterations in frontolimbic brain functioning during regulation. However, little is known about differences in brain function when comparing regulatory strategies. Reappraisal and emotional acceptance are effective in downregulating negative affect, and are components of effective depression psychotherapies. Investigating neural mechanisms of reappraisal vs emotional acceptance in remitted major depressive disorder (rMDD) may yield novel mechanistic insights into depression risk and prevention. Thirty-seven individuals (18 rMDD, 19 controls) were assessed during a functional magnetic resonance imaging task requiring reappraisal, emotional acceptance or no explicit regulation while viewing sad images. Lower negative affect was reported following reappraisal than acceptance, and was lower following acceptance than no explicit regulation. In controls, the acceptance > reappraisal contrast revealed greater activation in left insular cortex and right prefrontal gyrus, and less activation in several other prefrontal regions. Compared with controls, the rMDD group had greater paracingulate and right midfrontal gyrus (BA 8) activation during reappraisal relative to acceptance. Compared with reappraisal, acceptance is associated with activation in regions linked to somatic and emotion awareness, although this activation is associated with less reduction in negative affect. Additionally, a history of MDD moderated these effects. PMID:25617820

Neural Correlates of Emotion Regulation in Patients with Schizophrenia and Non-Affected Siblings

PubMed Central

van der Velde, Jorien; Pijnenborg, Gerdina; Wiersma, Durk; Bruggeman, Richard; Aleman, André

2014-01-01

Background Patients with schizophrenia often experience problems regulating their emotions. Non-affected relatives show similar difficulties, although to a lesser extent, and the neural basis of such difficulties remains to be elucidated. In the current paper we investigated whether schizophrenia patients, non-affected siblings and healthy controls (HC) exhibit differences in brain activation during emotion regulation. Methods All subjects (n = 20 per group) performed an emotion regulation task while they were in an fMRI scanner. The task contained two experimental conditions for the down-regulation of emotions (reappraise and suppress), in which IAPS pictures were used to generate a negative affect. We also assessed whether the groups differed in emotion regulation strategies used in daily life by means of the emotion regulation questionnaire (ERQ). Results Though the overall negative affect was higher for patients as well as for siblings compared to HC for all conditions, all groups reported decreased negative affect after both regulation conditions. Nonetheless, neuroimaging results showed hypoactivation relative to HC in VLPFC, insula, middle temporal gyrus, caudate and thalamus for patients when reappraising negative pictures. In siblings, the same pattern was evident as in patients, but only in cortical areas. Conclusions Given that all groups performed similarly on the emotion regulation task, but differed in overall negative affect ratings and brain activation, our findings suggest reduced levels of emotion regulation processing in neural circuits in patients with schizophrenia. Notably, this also holds for siblings, albeit to a lesser extent, indicating that it may be part and parcel of a vulnerability for psychosis. PMID:24941136

Autonomic effects of cognitive reappraisal and acceptance in social anxiety: evidence for common and distinct pathways for parasympathetic reactivity.

PubMed

Cristea, Ioana A; Valenza, Gaetano; Scilingo, Enzo Pasquale; Szentágotai Tătar, Aurora; Gentili, Claudio; David, Daniel

2014-12-01

Few studies investigated the effects of emotion regulation strategies on autonomic parameters in socially anxious individuals. We asked 99 socially anxious participants to give an impromptu speech in front of an audience in a virtual reality environment. In the anticipation phase, they practiced an emotion regulation strategy: negative functional reappraisal, acceptance, negative dysfunctional reappraisal. All strategies led to decreases in parasympathetic activity and increases in heart rate during anticipation. Parasympathetic activity remained low in the recovery phase, while heart rate increased, indicating a possible rebound effect of social performance. Exploratory moderation analysis revealed that for subjects with higher social anxiety, acceptance led to increased parasympathetic activity in the anticipation and recovery phases than negative functional reappraisal. Our results indicate that although globally parasympathetic reactivity seems to be a more general marker of simply attempting to regulate emotions, it could help distinguish between emotion regulation strategies for some participant subgroups. Copyright © 2014 Elsevier Ltd. All rights reserved.

RNA sensor LGP2 inhibits TRAF ubiquitin ligase to negatively regulate innate immune signaling.

PubMed

Parisien, Jean-Patrick; Lenoir, Jessica J; Mandhana, Roli; Rodriguez, Kenny R; Qian, Kenin; Bruns, Annie M; Horvath, Curt M

2018-06-01

The production of type I interferon (IFN) is essential for cellular barrier functions and innate and adaptive antiviral immunity. In response to virus infections, RNA receptors RIG-I and MDA5 stimulate a mitochondria-localized signaling apparatus that uses TRAF family ubiquitin ligase proteins to activate master transcription regulators IRF3 and NFκB, driving IFN and antiviral target gene expression. Data indicate that a third RNA receptor, LGP2, acts as a negative regulator of antiviral signaling by interfering with TRAF family proteins. Disruption of LGP2 expression in cells results in earlier and overactive transcriptional responses to virus or dsRNA LGP2 associates with the C-terminus of TRAF2, TRAF3, TRAF5, and TRAF6 and interferes with TRAF ubiquitin ligase activity. TRAF interference is independent of LGP2 ATP hydrolysis, RNA binding, or its C-terminal domain, and LGP2 can regulate TRAF-mediated signaling pathways in trans , including IL-1β, TNFα, and cGAMP These findings provide a unique mechanism for LGP2 negative regulation through TRAF suppression and extend the potential impact of LGP2 negative regulation beyond the IFN antiviral response. © 2018 The Authors.

Measuring self-regulation in a physically active context: Psychometric analyses of scores derived from an observer-rated measure of self-regulation.

PubMed

Lakes, Kimberley D

2013-10-01

The purpose of this study is to report psychometric properties of scores obtained using a novel observer-rated measure of children's self-regulation, the Response to Challenge Scale (RCS). The RCS was developed to rate children's self-regulatory abilities in a physically active context (e.g., while completing a physical challenge course). The RCS and other study measures were administered in a private school sample of 207 children. Analyses of score distributions indicated that the RCS was able to capture variance among children in self-regulatory abilities; the distribution was normal for the Affective, Cognitive, and Total Self-Regulation scales. Validity analyses revealed significant positive correlations between Cognitive, Affective, Motor, and Total Self-Regulation and executive function task performance; significant negative correlations between Cognitive Regulation and teacher-rated hyperactivity and inattention; significant negative correlations between Affective, Motor, and Total Self-Regulation and teacher ratings of peer problems; and significant positive correlations between Cognitive and Affective Regulation and parent ratings of prosocial behavior. Parent and teacher rated Total Difficulties scores were both negatively correlated with RCS Total Self-Regulation scores. Results suggest that it is possible for observers to rate self-regulatory abilities in the context of physical activities, and that these ratings correspond with performance on tasks requiring executive function as well as teacher and parent ratings of children's difficulties.

The regulation of the Z- and G-box containing promoters by light signaling components, SPA1 and MYC2, in Arabidopsis.

PubMed

Gangappa, Sreeramaiah N; Maurya, Jay P; Yadav, Vandana; Chattopadhyay, Sudip

2013-01-01

Although many transcription factors and regulatory proteins have been identified and functionally characterized in light signaling pathways, photoperception to transcription remains largely fragmented. The Z-box is one of the LREs (Light responsive elements) that plays important role in the regulation of transcription during light-controlled Arabidopsis seedling development. The involvement of photoreceptors in the modulation of the activity of the Z-box containing promoters has been demonstrated. However, the role of downstream signaling components such as SPA1 and MYC2/ZBF1, which are functionally interrelated, remains unknown. In this study, we have investigated the regulation of the Z-box containing synthetic and native promoters by SPA1 and MYC2 by using stable transgenic lines. Our studies suggest that SPA1 negatively regulates the expression of CAB1 native promoter. MYC2 negatively regulates the activity of Z- and/or G-box containing synthetic as well as native promoters irrespective of light quality. Moreover, MYC2 negatively regulates the expression of Z/G-NOS101-GUS even in the darkness. Furthermore, analyses of tissue specific expression in adult plants suggest that MYC2 strongly regulates the activity of Z- and G-box containing promoters specifically in leaves and stems. In roots, whereas MYC2 positively regulates the activity of the Z-box containing synthetic promoter, it does not seem to control the activity of the G-box containing promoters. Taken together, these results provide insights into SPA1- and MYC2-mediated transcriptional regulation of the Z- and G-box containing promoters in light signaling pathways.

Financial Incentives Differentially Regulate Neural Processing of Positive and Negative Emotions during Value-Based Decision-Making

PubMed Central

Farrell, Anne M.; Goh, Joshua O. S.; White, Brian J.

2018-01-01

Emotional and economic incentives often conflict in decision environments. To make economically desirable decisions then, deliberative neural processes must be engaged to regulate automatic emotional reactions. In this functional magnetic resonance imaging (fMRI) study, we evaluated how fixed wage (FW) incentives and performance-based (PB) financial incentives, in which pay is proportional to outcome, differentially regulate positive and negative emotional reactions to hypothetical colleagues that conflicted with the economics of available alternatives. Neural activity from FW to PB incentive contexts decreased for positive emotional stimuli but increased for negative stimuli in middle temporal, insula, and medial prefrontal regions. In addition, PB incentives further induced greater responses to negative than positive emotional decisions in the frontal and anterior cingulate regions involved in emotion regulation. Greater response to positive than negative emotional features in these regions also correlated with lower frequencies of economically desirable choices. Our findings suggest that whereas positive emotion regulation involves a reduction of responses in valence representation regions, negative emotion regulation additionally engages brain regions for deliberative processing and signaling of incongruous events. PMID:29487519

Financial Incentives Differentially Regulate Neural Processing of Positive and Negative Emotions during Value-Based Decision-Making.

PubMed

Farrell, Anne M; Goh, Joshua O S; White, Brian J

2018-01-01

Emotional and economic incentives often conflict in decision environments. To make economically desirable decisions then, deliberative neural processes must be engaged to regulate automatic emotional reactions. In this functional magnetic resonance imaging (fMRI) study, we evaluated how fixed wage (FW) incentives and performance-based (PB) financial incentives, in which pay is proportional to outcome, differentially regulate positive and negative emotional reactions to hypothetical colleagues that conflicted with the economics of available alternatives. Neural activity from FW to PB incentive contexts decreased for positive emotional stimuli but increased for negative stimuli in middle temporal, insula, and medial prefrontal regions. In addition, PB incentives further induced greater responses to negative than positive emotional decisions in the frontal and anterior cingulate regions involved in emotion regulation. Greater response to positive than negative emotional features in these regions also correlated with lower frequencies of economically desirable choices. Our findings suggest that whereas positive emotion regulation involves a reduction of responses in valence representation regions, negative emotion regulation additionally engages brain regions for deliberative processing and signaling of incongruous events.

Opposing effects of negative emotion on amygdalar and hippocampal memory for items and associations

PubMed Central

Horner, Aidan J.; Hørlyck, Lone D.; Burgess, Neil

2016-01-01

Although negative emotion can strengthen memory of an event it can also result in memory disturbances, as in post-traumatic stress disorder (PTSD). We examined the effects of negative item content on amygdalar and hippocampal function in memory for the items themselves and for the associations between them. During fMRI, we examined encoding and retrieval of paired associates made up of all four combinations of neutral and negative images. At test, participants were cued with an image and, if recognised, had to retrieve the associated (target) image. The presence of negative images increased item memory but reduced associative memory. At encoding, subsequent item recognition correlated with amygdala activity, while subsequent associative memory correlated with hippocampal activity. Hippocampal activity was reduced by the presence of negative images, during encoding and correct associative retrieval. In contrast, amygdala activity increased for correctly retrieved negative images, even when cued by a neutral image. Our findings support a dual representation account, whereby negative emotion up-regulates the amygdala to strengthen item memory but down-regulates the hippocampus to weaken associative representations. These results have implications for the development and treatment of clinical disorders in which diminished associations between emotional stimuli and their context contribute to negative symptoms, as in PTSD. PMID:26969864

Metabolic and hormone influences on emotion processing during menopause.

PubMed

Berent-Spillson, Alison; Marsh, Courtney; Persad, Carol; Randolph, John; Zubieta, Jon-Kar; Smith, Yolanda

2017-02-01

Disturbances of emotion regulation and depressive symptoms are common during the menopause transition. Reproductive hormone levels are not directly correlated with depressive symptoms, and other factors may influence mood symptoms during menopause. In this study, we sought to determine the role of metabolic function in mood symptoms during menopause, hypothesizing an association with menopause status and long-term glucose load. We studied 54 women across three menopause transition stages (15 premenopause, 11 perimenopause, and 28 postmenopause), examining effects of age, hormones, and metabolism on mood and neural activation during emotional discrimination. We assessed participants using behavioral and functional MRI measures of negative emotion and emotion discrimination, and glycated hemoglobin A1c, to assess long-term glucose load. We found that emotionally unpleasant images activated emotion regulation (amygdala) and cognitive association brain regions (prefrontal cortex, posterior cingulate, temporal-parietal-occipital (TPO) junction, hippocampus). Cognitive association region activity increased with menopause stage. Perimenopausal women had left TPO junction activation, and postmenopausal women had prefrontal cortex, posterior cingulate, and TPO junction activation. Negative affect was associated with decreased amygdala activation, while depression symptoms and negative mood were associated with increased TPO junction activation. Hemoglobin A1c was associated with negative interpretation bias of neutral images and cognitive region recruitment during emotion discrimination. FSH levels, indicating menopause stage, were associated with negative mood. Age was not associated with any behavioral measures or activation patterns during the emotion task. Our results suggest that an interaction between metabolic and hormonal factors may influence emotion regulation, leading to increased risk for depression during menopause. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neurons for hunger and thirst transmit a negative-valence teaching signal

PubMed Central

Gong, Rong; Magnus, Christopher J.; Yu, Yang; Sternson, Scott M.

2015-01-01

Homeostasis is a biological principle for regulation of essential physiological parameters within a set range. Behavioural responses due to deviation from homeostasis are critical for survival, but motivational processes engaged by physiological need states are incompletely understood. We examined motivational characteristics and dynamics of two separate neuron populations that regulate energy and fluid homeostasis by using cell type-specific activity manipulations in mice. We found that starvation-sensitive AGRP neurons exhibit properties consistent with a negative-valence teaching signal. Mice avoided activation of AGRP neurons, indicating that AGRP neuron activity has negative valence. AGRP neuron inhibition conditioned preference for flavours and places. Correspondingly, deep-brain calcium imaging revealed that AGRP neuron activity rapidly reduced in response to food-related cues. Complementary experiments activating thirst-promoting neurons also conditioned avoidance. Therefore, these need-sensing neurons condition preference for environmental cues associated with nutrient or water ingestion, which is learned through reduction of negative-valence signals during restoration of homeostasis. PMID:25915020

TRIM45 negatively regulates NF-{kappa}B-mediated transcription and suppresses cell proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shibata, Mio; Sato, Tomonobu; Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638

2012-06-22

Highlights: Black-Right-Pointing-Pointer NF-{kappa}B plays an important role in cell survival and carcinogenesis. Black-Right-Pointing-Pointer TRIM45 negatively regulates TNF{alpha}-induced NF-{kappa}B-mediated transcription. Black-Right-Pointing-Pointer TRIM45 overexpression suppresses cell growth. Black-Right-Pointing-Pointer TRIM45 acts as a repressor for the NF-{kappa}B signal and regulates cell growth. -- Abstract: The NF-{kappa}B signaling pathway plays an important role in cell survival, immunity, inflammation, carcinogenesis, and organogenesis. Activation of NF-{kappa}B is regulated by several posttranslational modifications including phosphorylation, neddylation and ubiquitination. The NF-{kappa}B signaling pathway is activated by two distinct signaling mechanisms and is strictly modulated by the ubiquitin-proteasome system. It has been reported that overexpression of TRIM45, one ofmore » the TRIM family ubiquitin ligases, suppresses transcriptional activities of Elk-1 and AP-1, which are targets of the MAPK signaling pathway. In this study, we showed that TRIM45 also negatively regulates TNF{alpha}-induced NF-{kappa}B-mediated transcription by a luciferase reporter assay and that TRIM45 lacking a RING domain also has an activity to inhibit the NF-{kappa}B signal. Moreover, we found that TRIM45 overexpression suppresses cell growth. These findings suggest that TRIM45 acts as a repressor for the NF-{kappa}B signal and regulates cell growth.« less

Effects of Mindfulness-Based Stress Reduction (MBSR) on Emotion Regulation in Social Anxiety Disorder

PubMed Central

Goldin, Philippe R.; Gross, James J.

2014-01-01

Mindfulness-based stress reduction (MBSR) is an established program shown to reduce symptoms of stress, anxiety, and depression. MBSR is believed to alter emotional responding by modifying cognitive–affective processes. Given that social anxiety disorder (SAD) is characterized by emotional and attentional biases as well as distorted negative self-beliefs, we examined MBSR-related changes in the brain-behavior indices of emotional reactivity and regulation of negative self-beliefs in patients with SAD. Sixteen patients underwent functional MRI while reacting to negative self-beliefs and while regulating negative emotions using 2 types of attention deployment emotion regulation—breath-focused attention and distraction-focused attention. Post-MBSR, 14 patients completed neuroimaging assessments. Compared with baseline, MBSR completers showed improvement in anxiety and depression symptoms and self-esteem. During the breath-focused attention task (but not the distraction-focused attention task), they also showed (a) decreased negative emotion experience, (b) reduced amygdala activity, and (c) increased activity in brain regions implicated in attentional deployment. MBSR training in patients with SAD may reduce emotional reactivity while enhancing emotion regulation. These changes might facilitate reduction in SAD-related avoidance behaviors, clinical symptoms, and automatic emotional reactivity to negative self-beliefs in adults with SAD. PMID:20141305

Body-related self-conscious emotions relate to physical activity motivation and behavior in men.

PubMed

Castonguay, Andree L; Pila, Eva; Wrosch, Carsten; Sabiston, Catherine M

2015-05-01

The aim of this study was to examine the associations between the body-related self-conscious emotions of shame, guilt, and pride and physical activity motivation and behavior among adult males. Specifically, motivation regulations (external, introjected, indentified, intrinsic) were examined as possible mediators between each of the body-related self-conscious emotions and physical activity behavior. A cross-sectional study was conducted with adult men (N = 152; Mage = 23.72, SD = 10.92 years). Participants completed a questionnaire assessing body-related shame, guilt, authentic pride, hubristic pride, motivational regulations, and leisure-time physical activity. In separate multiple mediation models, body-related shame was positively associated with external and introjected regulations and negatively correlated with intrinsic regulation. Guilt was positively linked to external, introjected, and identified regulations. Authentic pride was negatively related to external regulation and positively correlated with both identified and intrinsic regulations and directly associated with physical activity behavior. Hubristic pride was positively associated with intrinsic regulation. Overall, there were both direct and indirect effects via motivation regulations between body-related self-conscious emotions and physical activity (R(2) shame = .15, guilt = .16, authentic pride = .18, hubristic pride = .16). These findings highlight the importance of targeting and understanding self-conscious emotions contextualized to the body and links to motivation and positive health behavior among men. © The Author(s) 2014.

Neural indicators of emotion regulation via acceptance vs reappraisal in remitted major depressive disorder.

PubMed

Smoski, Moria J; Keng, Shian-Ling; Ji, Jie Lisa; Moore, Tyler; Minkel, Jared; Dichter, Gabriel S

2015-09-01

Mood disorders are characterized by impaired emotion regulation abilities, reflected in alterations in frontolimbic brain functioning during regulation. However, little is known about differences in brain function when comparing regulatory strategies. Reappraisal and emotional acceptance are effective in downregulating negative affect, and are components of effective depression psychotherapies. Investigating neural mechanisms of reappraisal vs emotional acceptance in remitted major depressive disorder (rMDD) may yield novel mechanistic insights into depression risk and prevention. Thirty-seven individuals (18 rMDD, 19 controls) were assessed during a functional magnetic resonance imaging task requiring reappraisal, emotional acceptance or no explicit regulation while viewing sad images. Lower negative affect was reported following reappraisal than acceptance, and was lower following acceptance than no explicit regulation. In controls, the acceptance > reappraisal contrast revealed greater activation in left insular cortex and right prefrontal gyrus, and less activation in several other prefrontal regions. Compared with controls, the rMDD group had greater paracingulate and right midfrontal gyrus (BA 8) activation during reappraisal relative to acceptance. Compared with reappraisal, acceptance is associated with activation in regions linked to somatic and emotion awareness, although this activation is associated with less reduction in negative affect. Additionally, a history of MDD moderated these effects. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Regulation of voltage-gated sodium channel expression in cancer: hormones, growth factors and auto-regulation

PubMed Central

Fraser, Scott P.; Ozerlat-Gunduz, Iley; Brackenbury, William J.; Fitzgerald, Elizabeth M.; Campbell, Thomas M.; Coombes, R. Charles; Djamgoz, Mustafa B. A.

2014-01-01

Although ion channels are increasingly being discovered in cancer cells in vitro and in vivo, and shown to contribute to different aspects and stages of the cancer process, much less is known about the mechanisms controlling their expression. Here, we focus on voltage-gated Na+ channels (VGSCs) which are upregulated in many types of carcinomas where their activity potentiates cell behaviours integral to the metastatic cascade. Regulation of VGSCs occurs at a hierarchy of levels from transcription to post-translation. Importantly, mainstream cancer mechanisms, especially hormones and growth factors, play a significant role in the regulation. On the whole, in major hormone-sensitive cancers, such as breast and prostate cancer, there is a negative association between genomic steroid hormone sensitivity and functional VGSC expression. Activity-dependent regulation by positive feedback has been demonstrated in strongly metastatic cells whereby the VGSC is self-sustaining, with its activity promoting further functional channel expression. Such auto-regulation is unlike normal cells in which activity-dependent regulation occurs mostly via negative feedback. Throughout, we highlight the possible clinical implications of functional VGSC expression and regulation in cancer. PMID:24493753

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Jinqi; Cook, Aaron A.; Bergmeier, Wolfgang

The dynamic regulation of ERK1 and -2 (ERK1/2) is required for precise signal transduction controlling cell proliferation, differentiation, and survival. However, the underlying mechanisms regulating the activation of ERK1/2 are not completely understood. In this study, we show that phosphorylation of RasGRP2, a guanine nucleotide exchange factor (GEF), inhibits its ability to activate the small GTPase Rap1 that ultimately leads to decreased activation of ERK1/2 in cells. ERK2 phosphorylates RasGRP2 at Ser394 located in the linker region implicated in its autoinhibition. These studies identify RasGRP2 as a novel substrate of ERK1/2 and define a negative-feedback loop that regulates the BRaf–MEK–ERKmore » signaling cascade. This negative-feedback loop determines the amplitude and duration of active ERK1/2. -- Highlights: •ERK2 phosphorylates the guanine nucleotide exchange factor RasGRP2 at Ser394. •Phosphorylated RasGRP2 has decreased capacity to active Rap1b in vitro and in cells. •Phosphorylation of RasGRP2 by ERK1/2 introduces a negative-feedback loop into the BRaf-MEK-ERK pathway.« less

Neural circuits of emotion regulation: a comparison of mindfulness-based and cognitive reappraisal strategies.

PubMed

Opialla, Sarah; Lutz, Jacqueline; Scherpiet, Sigrid; Hittmeyer, Anna; Jäncke, Lutz; Rufer, Michael; Grosse Holtforth, Martin; Herwig, Uwe; Brühl, Annette B

2015-02-01

Dealing with one's emotions is a core skill in everyday life. Effective cognitive control strategies have been shown to be neurobiologically represented in prefrontal structures regulating limbic regions. In addition to cognitive strategies, mindfulness-associated methods are increasingly applied in psychotherapy. We compared the neurobiological mechanisms of these two strategies, i.e. cognitive reappraisal and mindfulness, during both the cued expectation and perception of negative and potentially negative emotional pictures. Fifty-three healthy participants were examined with functional magnetic resonance imaging (47 participants included in analysis). Twenty-four subjects applied mindfulness, 23 used cognitive reappraisal. On the neurofunctional level, both strategies were associated with comparable activity of the medial prefrontal cortex and the amygdala. When expecting negative versus neutral stimuli, the mindfulness group showed stronger activations in ventro- and dorsolateral prefrontal cortex, supramarginal gyrus as well as in the left insula. During the perception of negative versus neutral stimuli, the two groups only differed in an increased activity in the caudate in the cognitive group. Altogether, both strategies recruited overlapping brain regions known to be involved in emotion regulation. This result suggests that common neural circuits are involved in the emotion regulation by mindfulness-based and cognitive reappraisal strategies. Identifying differential activations being associated with the two strategies in this study might be one step towards a better understanding of differential mechanisms of change underlying frequently used psychotherapeutic interventions.

Tissue-Specific Regulation of Chromatin Insulator Function

PubMed Central

Matzat, Leah H.; Dale, Ryan K.; Moshkovich, Nellie; Lei, Elissa P.

2012-01-01

Chromatin insulators organize the genome into distinct transcriptional domains and contribute to cell type–specific chromatin organization. However, factors regulating tissue-specific insulator function have not yet been discovered. Here we identify the RNA recognition motif-containing protein Shep as a direct interactor of two individual components of the gypsy insulator complex in Drosophila. Mutation of shep improves gypsy-dependent enhancer blocking, indicating a role as a negative regulator of insulator activity. Unlike ubiquitously expressed core gypsy insulator proteins, Shep is highly expressed in the central nervous system (CNS) with lower expression in other tissues. We developed a novel, quantitative tissue-specific barrier assay to demonstrate that Shep functions as a negative regulator of insulator activity in the CNS but not in muscle tissue. Additionally, mutation of shep alters insulator complex nuclear localization in the CNS but has no effect in other tissues. Consistent with negative regulatory activity, ChIP–seq analysis of Shep in a CNS-derived cell line indicates substantial genome-wide colocalization with a single gypsy insulator component but limited overlap with intact insulator complexes. Taken together, these data reveal a novel, tissue-specific mode of regulation of a chromatin insulator. PMID:23209434

TRAF family member-associated NF-κB activator (TANK) is a negative regulator of osteoclastogenesis and bone formation.

PubMed

Maruyama, Kenta; Kawagoe, Tatsukata; Kondo, Takeshi; Akira, Shizuo; Takeuchi, Osamu

2012-08-17

The differentiation of bone-resorbing osteoclasts is induced by RANKL signaling, and leads to the activation of NF-κB via TRAF6 activation. TRAF family member-associated NF-κB activator (TANK) acts as a negative regulator of Toll-like receptors (TLRs) and B-cell receptor (BCR) signaling by inhibiting TRAF6 activation. Tank(-/-) mice spontaneously develop autoimmune glomerular nephritis in an IL-6-dependent manner. Despite its importance in the TCRs and BCR-activated TRAF6 inhibition, the involvement of TANK in RANKL signaling is poorly understood. Here, we report that TANK is a negative regulator of osteoclast differentiation. The expression levels of TANK mRNA and protein were up-regulated during RANKL-induced osteoclastogenesis, and overexpression of TANK in vitro led to a decrease in osteoclast formation. The in vitro osteoclastogenesis of Tank(-/-) cells was significantly increased, accompanied by increased ubiquitination of TRAF6 and enhanced canonical NF-κB activation in response to RANKL stimulation. Tank(-/-) mice showed severe trabecular bone loss, but increased cortical bone mineral density, because of enhanced bone erosion and formation. TANK mRNA expression was induced during osteoblast differentiation and Tank(-/-) osteoblasts exhibited enhaced NF-κB activation, IL-11 expression, and bone nodule formation than wild-type control cells. Finally, wild-type mice transplanted with bone marrow cells from Tank(-/-) mice showed trabecular bone loss analogous to that in Tank(-/-) mice. These findings demonstrate that TANK is critical for osteoclastogenesis by regulating NF-κB, and is also important for proper bone remodeling.

TRAF Family Member-associated NF-κB Activator (TANK) Is a Negative Regulator of Osteoclastogenesis and Bone Formation*

PubMed Central

Maruyama, Kenta; Kawagoe, Tatsukata; Kondo, Takeshi; Akira, Shizuo; Takeuchi, Osamu

2012-01-01

The differentiation of bone-resorbing osteoclasts is induced by RANKL signaling, and leads to the activation of NF-κB via TRAF6 activation. TRAF family member-associated NF-κB activator (TANK) acts as a negative regulator of Toll-like receptors (TLRs) and B-cell receptor (BCR) signaling by inhibiting TRAF6 activation. Tank−/− mice spontaneously develop autoimmune glomerular nephritis in an IL-6-dependent manner. Despite its importance in the TCRs and BCR-activated TRAF6 inhibition, the involvement of TANK in RANKL signaling is poorly understood. Here, we report that TANK is a negative regulator of osteoclast differentiation. The expression levels of TANK mRNA and protein were up-regulated during RANKL-induced osteoclastogenesis, and overexpression of TANK in vitro led to a decrease in osteoclast formation. The in vitro osteoclastogenesis of Tank−/− cells was significantly increased, accompanied by increased ubiquitination of TRAF6 and enhanced canonical NF-κB activation in response to RANKL stimulation. Tank−/− mice showed severe trabecular bone loss, but increased cortical bone mineral density, because of enhanced bone erosion and formation. TANK mRNA expression was induced during osteoblast differentiation and Tank−/− osteoblasts exhibited enhaced NF-κB activation, IL-11 expression, and bone nodule formation than wild-type control cells. Finally, wild-type mice transplanted with bone marrow cells from Tank−/− mice showed trabecular bone loss analogous to that in Tank−/− mice. These findings demonstrate that TANK is critical for osteoclastogenesis by regulating NF-κB, and is also important for proper bone remodeling. PMID:22773835

Maladaptive and adaptive emotion regulation through music: a behavioral and neuroimaging study of males and females

PubMed Central

Carlson, Emily; Saarikallio, Suvi; Toiviainen, Petri; Bogert, Brigitte; Kliuchko, Marina; Brattico, Elvira

2015-01-01

Music therapists use guided affect regulation in the treatment of mood disorders. However, self-directed uses of music in affect regulation are not fully understood. Some uses of music may have negative effects on mental health, as can non-music regulation strategies, such as rumination. Psychological testing and functional magnetic resonance imaging (fMRI) were used explore music listening strategies in relation to mental health. Participants (n = 123) were assessed for depression, anxiety and Neuroticism, and uses of Music in Mood Regulation (MMR). Neural responses to music were measured in the medial prefrontal cortex (mPFC) in a subset of participants (n = 56). Discharge, using music to express negative emotions, related to increased anxiety and Neuroticism in all participants and particularly in males. Males high in Discharge showed decreased activity of mPFC during music listening compared with those using less Discharge. Females high in Diversion, using music to distract from negative emotions, showed more mPFC activity than females using less Diversion. These results suggest that the use of Discharge strategy can be associated with maladaptive patterns of emotional regulation, and may even have long-term negative effects on mental health. This finding has real-world applications in psychotherapy and particularly in clinical music therapy. PMID:26379529

HPK1 competes with ADAP for SLP-76 binding and via Rap1 negatively affects T-cell adhesion.

PubMed

Patzak, Irene M; Königsberger, Sebastian; Suzuki, Akira; Mak, Tak W; Kiefer, Friedemann

2010-11-01

The hematopoietic progenitor kinase 1 (HPK1) signals into MAPK and NFκB pathways downstream of immunoreceptors, but enigmatically is a negative regulator of leukocytes. Here, we report a novel role for HPK1 in regulating the activation of the adhesion molecule leukocyte function-associated antigen-1 (LFA-1). Upon TCR stimulation, mediated by binding of adhesion and degranulation promoting adaptor protein (ADAP) to SLP-76, a ternary complex composed of ADAP/55-kDa src kinase associated phosphoprotein (SKAP-55) and RIAM translocates to the membrane and causes membrane recruitment of the active small GTPase Ras-related protein 1 (Rap1). Active Rap1, via its binding to RapL (regulator for cell adhesion and polarization enriched in lymphoid tissues), mediates LFA-1 integrin activation. We show here that HPK1, which also binds SLP-76, compete with ADAP for SLP-76 binding. In addition, HPK1 dampens Rap1 activation, resulting in decreased LFA-1 activity. Analysis of HPK1-deficient T cells revealed increased ADAP recruitment to SLP-76 and elevated Rap1 activation in those cells, leading to increased adhesion to ICAM-1 and cell spreading. Altogether, these results describe a novel function for HPK1 in linking TCR signaling to cell adhesion regulation and provide a mechanistic explanation for the negative regulatory role of HPK1 in T-cell biology.

Parvalbumin Interneurons of Central Amygdala Regulate the Negative Affective States and the Expression of Corticotrophin-Releasing Hormone During Morphine Withdrawal

PubMed Central

Wang, Li; Shen, Minjie; Jiang, Changyou

2016-01-01

Background: The central nucleus of the amygdala (CeA) is a crucial component of the neuronal circuitry mediating aversive emotion. Its role in the negative affective states during drug withdrawal includes changes in opioidergic, GABAergic, and corticotropin-releasing factor neurotransmission. However, the modulation of the neurobiological interconnectivity in the CeA and its effects in the negative reinforcement of drug dependents are poorly understood. Method: We performed electrophysiological recordings to assess the membrane excitability of parvalbumin (PV)+ interneurons in the CeA during chronic morphine withdrawal. We tested the morphine withdrawal–induced negative affective states, such as the aversive (assessed by conditioned place aversion), anxiety (assessed by elevated plus maze), and anhedonic-like (assessed by saccharin preference test) behaviors, as well as the mRNA level of corticotropin-releasing hormone (CRH) via optogenetic inhibition or activation of PV+ interneurons in the CeA. Result: Chronic morphine withdrawal increased the firing rate of CeA PV+ interneurons. Optogenetic inhibition of the activity of CeA PV+ interneurons attenuated the morphine withdrawal–induced negative affective states, such as the aversive, anxiety, and anhedonic-like behaviors, while direct activation of CeA PV+ interneurons could trigger those negative affective-like behaviors. Optogenetic inhibition of the CeA PV+ interneurons during the morphine withdrawal significantly attenuated the elevated CRH mRNA level in the CeA. Conclusion: The activity of PV+ interneurons in the CeA was up-regulated during chronic morphine withdrawal. The activation of PV+ interneurons during morphine withdrawal was crucial for the induction of the negative emotion and the up-regulation of CRH mRNA levels in the CeA. PMID:27385383

Intrinsic functional connectivity underlying successful emotion regulation of angry faces

PubMed Central

Morawetz, Carmen; Kellermann, Tanja; Kogler, Lydia; Radke, Sina; Blechert, Jens; Derntl, Birgit

2016-01-01

Most of our social interaction is naturally based on emotional information derived from the perception of faces of other people. Negative facial expressions of a counterpart might trigger negative emotions and initiate emotion regulatory efforts to reduce the impact of the received emotional message in a perceiver. Despite the high adaptive value of emotion regulation in social interaction, the neural underpinnings of it are largely unknown. To remedy this, this study investigated individual differences in emotion regulation effectiveness during the reappraisal of angry faces on the underlying functional activity using functional magnetic resonance imaging (fMRI) as well as the underlying functional connectivity using resting-state fMRI. Greater emotion regulation ability was associated with greater functional activity in the ventromedial prefrontal cortex. Furthermore, greater functional coupling between activity in the ventrolateral prefrontal cortex and the amygdala was associated with emotion regulation success. Our findings provide a first link between prefrontal cognitive control and subcortical emotion processing systems during successful emotion regulation in an explicitly social context. PMID:27510495

Viral infection upregulates myostatin promoter activity in orange-spotted grouper (Epinephelus coioides)

PubMed Central

Chen, Yi-Tien; Lin, Chao-Fen; Chen, Young-Mao; Lo, Chih-En; Chen, Wan-Erh

2017-01-01

Myostatin is a negative regulator of myogenesis and has been suggested to be an important factor in the development of muscle wasting during viral infection. The objective of this study was to characterize the main regulatory element of the grouper myostatin promoter and to study changes in promoter activity due to viral stimulation. In vitro and in vivo experiments indicated that the E-box E6 is a positive cis-and trans-regulation motif, and an essential binding site for MyoD. In contrast, the E-box E5 is a dominant negative cis-regulatory. The characteristics of grouper myostatin promoter are similar in regulation of muscle growth to that of other species, but mainly through specific regulatory elements. According to these results, we conducted a study to investigate the effect of viral infection on myostatin promoter activity and its regulation. The nervous necrosis virus (NNV) treatment significantly induced myostatin promoter activity. The present study is the first report describing that specific myostatin motifs regulate promoter activity and response to viral infection. PMID:29036192

Viral infection upregulates myostatin promoter activity in orange-spotted grouper (Epinephelus coioides).

PubMed

Chen, Yi-Tien; Lin, Chao-Fen; Chen, Young-Mao; Lo, Chih-En; Chen, Wan-Erh; Chen, Tzong-Yueh

2017-01-01

Myostatin is a negative regulator of myogenesis and has been suggested to be an important factor in the development of muscle wasting during viral infection. The objective of this study was to characterize the main regulatory element of the grouper myostatin promoter and to study changes in promoter activity due to viral stimulation. In vitro and in vivo experiments indicated that the E-box E6 is a positive cis-and trans-regulation motif, and an essential binding site for MyoD. In contrast, the E-box E5 is a dominant negative cis-regulatory. The characteristics of grouper myostatin promoter are similar in regulation of muscle growth to that of other species, but mainly through specific regulatory elements. According to these results, we conducted a study to investigate the effect of viral infection on myostatin promoter activity and its regulation. The nervous necrosis virus (NNV) treatment significantly induced myostatin promoter activity. The present study is the first report describing that specific myostatin motifs regulate promoter activity and response to viral infection.

Phosphorylation and activation of ubiquitin-specific protease-14 by Akt regulates the ubiquitin-proteasome system

PubMed Central

Xu, Daichao; Shan, Bing; Lee, Byung-Hoon; Zhu, Kezhou; Zhang, Tao; Sun, Huawang; Liu, Min; Shi, Linyu; Liang, Wei; Qian, Lihui; Xiao, Juan; Wang, Lili; Pan, Lifeng; Finley, Daniel; Yuan, Junying

2015-01-01

Regulation of ubiquitin-proteasome system (UPS), which controls the turnover of short-lived proteins in eukaryotic cells, is critical in maintaining cellular proteostasis. Here we show that USP14, a major deubiquitinating enzyme that regulates the UPS, is a substrate of Akt, a serine/threonine-specific protein kinase critical in mediating intracellular signaling transducer for growth factors. We report that Akt-mediated phosphorylation of USP14 at Ser432, which normally blocks its catalytic site in the inactive conformation, activates its deubiquitinating activity in vitro and in cells. We also demonstrate that phosphorylation of USP14 is critical for Akt to regulate proteasome activity and consequently global protein degradation. Since Akt can be activated by a wide range of growth factors and is under negative control by phosphoinosotide phosphatase PTEN, we suggest that regulation of UPS by Akt-mediated phosphorylation of USP14 may provide a common mechanism for growth factors to control global proteostasis and for promoting tumorigenesis in PTEN-negative cancer cells. DOI: http://dx.doi.org/10.7554/eLife.10510.001 PMID:26523394

AMPK Signaling in the Dorsal Hippocampus Negatively Regulates Contextual Fear Memory Formation

PubMed Central

Han, Ying; Luo, Yixiao; Sun, Jia; Ding, Zengbo; Liu, Jianfeng; Yan, Wei; Jian, Min; Xue, Yanxue; Shi, Jie; Wang, Ji-Shi; Lu, Lin

2016-01-01

Both the formation of long-term memory (LTM) and dendritic spine growth that serves as a physical basis for the long-term storage of information require de novo protein synthesis. Memory formation also critically depends on transcription. Adenosine monophosphate-activated protein kinase (AMPK) is a transcriptional regulator that has emerged as a major energy sensor that maintains cellular energy homeostasis. However, still unknown is its role in memory formation. In the present study, we found that AMPK is primarily expressed in neurons in the hippocampus, and then we demonstrated a time-dependent decrease in AMPK activity and increase in mammalian target of rapamycin complex 1 (mTORC1) activity after contextual fear conditioning in the CA1 but not CA3 area of the dorsal hippocampus. Using pharmacological methods and adenovirus gene transfer to bidirectionally regulate AMPK activity, we found that increasing AMPK activity in the CA1 impaired the formation of long-term fear memory, and decreasing AMPK activity enhanced fear memory formation. These findings were associated with changes in the phosphorylation of AMPK and p70s6 kinase (p70s6k) and expression of BDNF and membrane GluR1 and GluR2 in the CA1. Furthermore, the prior administration of an mTORC1 inhibitor blocked the enhancing effect of AMPK inhibition on fear memory formation, suggesting that this negative regulation of contextual fear memory by AMPK in the CA1 depends on the mTORC1 signaling pathway. Finally, we found that AMPK activity regulated hippocampal spine growth associated with memory formation. In summary, our results indicate that AMPK is a key negative regulator of plasticity and fear memory formation. PMID:26647974

Dusp5 negatively regulates IL-33-mediated eosinophil survival and function

PubMed Central

Holmes, Derek A; Yeh, Jung-Hua; Yan, Donghong; Xu, Min; Chan, Andrew C

2015-01-01

Mitogen-activated protein kinase (MAPK) activation controls diverse cellular functions including cellular survival, proliferation, and apoptosis. Tuning of MAPK activation is counter-regulated by a family of dual-specificity phosphatases (DUSPs). IL-33 is a recently described cytokine that initiates Th2 immune responses through binding to a heterodimeric IL-33Rα (ST2L)/IL-1α accessory protein (IL-1RAcP) receptor that coordinates activation of ERK and NF-κB pathways. We demonstrate here that DUSP5 is expressed in eosinophils, is upregulated following IL-33 stimulation and regulates IL-33 signaling. Dusp5−/− mice have prolonged eosinophil survival and enhanced eosinophil effector functions following infection with the helminth Nippostrongylus brasiliensis. IL-33-activated Dusp5−/− eosinophils exhibit increased cellular ERK1/2 activation and BCL-XL expression that results in enhanced eosinophil survival. In addition, Dusp5−/− eosinophils demonstrate enhanced IL-33-mediated activation and effector functions. Together, these data support a role for DUSP5 as a novel negative regulator of IL-33-dependent eosinophil function and survival. PMID:25398911

IGF-II-mediated downregulation of peroxisome proliferator-activated receptor-γ coactivator-1α in myoblast cells involves PI3K/Akt/FoxO1 signaling pathway.

PubMed

Mu, Xiaoyu; Qi, Weihong; Liu, Yunzhang; Zhou, Jianfeng; Li, Yun; Rong, Xiaozhi; Lu, Ling

2017-08-01

Insulin-like growth factor II (IGF-II) can stimulate myogenesis and is critically involved in skeletal muscle differentiation. The presence of negative regulators of this process, however, is not well explored. Here, we showed that in myoblast cells, IGF-II negatively regulated peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mRNA expression, while constitutive expression of PGC-1α induced myoblast differentiation. These results suggest that the negative regulation of PGC-1α by IGF-II may act as a negative feedback mechanism in IGF-II-induced myogenic differentiation. Reporter assays demonstrated that IGF-II suppresses the basal PGC-1α promoter activity. Blocking the IGF-II signaling pathway increased the endogenous PGC-1α levels. In addition, pharmacological inhibition of PI3 kinase activity prevented the downregulation of PGC-1α but the activation of mTOR was not required for this process. Importantly, further analysis showed that forkhead transcription factor FoxO1 contributes to mediating the effects of IGF-II on PGC-1 promoter activity. These findings indicate that IGF-II reduces PGC-1α expression in skeletal muscle cells through a mechanism involving PI3K-Akt-FoxO1 but not p38 MAPK or Erk1/2 MAPK pathways.

TRAF Family Member-Associated NF-κB Activator (TANK) Induced by RANKL Negatively Regulates Osteoclasts Survival and Function

PubMed Central

Wu, Mengrui; Wang, Yiping; Deng, Lianfu; Chen, Wei; Li, Yi-Ping

2012-01-01

Osteoclasts are the principle bone-resorbing cells. Precise control of balanced osteoclast activity is indispensable for bone homeostasis. Osteoclast activation mediated by RANK-TRAF6 axis has been clearly identified. However, a negative regulation-machinery in osteoclast remains unclear. TRAF family member-associated NF-κB activator (TANK) is induced by about 10 folds during osteoclastogenesis, according to a genome-wide analysis of gene expression before and after osteoclast maturation, and confirmed by western blot and quantitative RT-PCR. Bone marrow macrophages (BMMs) transduced with lentivirus carrying tank-shRNA were induced to form osteoclast in the presence of RANKL and M-CSF. Tank expression was downregulated by 90% by Tank-shRNA, which is confirmed by western blot. Compared with wild-type (WT) cells, osteoclastogenesis of Tank-silenced BMMs was increased, according to tartrate-resistant acid phosphatase (TRAP) stain on day 5 and day 7. Number of bone resorption pits by Tank-silenced osteoclasts was increased by 176% compared with WT cells, as shown by wheat germ agglutinin (WGA) stain and scanning electronic microscope (SEM) analysis. Survival rate of Tank-silenced mature osteoclast is also increased. However, acid production of Tank-knockdown cells was not changed compared with control cells. IκBα phosphorylation is increased in tank-silenced cells, indicating that TANK may negatively regulate NF-κB activity in osteoclast. In conclusion, Tank, whose expression is increased during osteoclastogenesis, inhibits osteoclast formation, activity and survival, by regulating NF-κB activity and c-FLIP expression. Tank enrolls itself in a negative feedback loop in bone resorption. These results may provide means for therapeutic intervention in diseases of excessive bone resorption. PMID:23139637

TRAF family member-associated NF-κB activator (TANK) induced by RANKL negatively regulates osteoclasts survival and function.

PubMed

Wu, Mengrui; Wang, Yiping; Deng, Lianfu; Chen, Wei; Li, Yi-Ping

2012-01-01

Osteoclasts are the principle bone-resorbing cells. Precise control of balanced osteoclast activity is indispensable for bone homeostasis. Osteoclast activation mediated by RANK-TRAF6 axis has been clearly identified. However, a negative regulation-machinery in osteoclast remains unclear. TRAF family member-associated NF-κB activator (TANK) is induced by about 10 folds during osteoclastogenesis, according to a genome-wide analysis of gene expression before and after osteoclast maturation, and confirmed by western blot and quantitative RT-PCR. Bone marrow macrophages (BMMs) transduced with lentivirus carrying tank-shRNA were induced to form osteoclast in the presence of RANKL and M-CSF. Tank expression was downregulated by 90% by Tank-shRNA, which is confirmed by western blot. Compared with wild-type (WT) cells, osteoclastogenesis of Tank-silenced BMMs was increased, according to tartrate-resistant acid phosphatase (TRAP) stain on day 5 and day 7. Number of bone resorption pits by Tank-silenced osteoclasts was increased by 176% compared with WT cells, as shown by wheat germ agglutinin (WGA) stain and scanning electronic microscope (SEM) analysis. Survival rate of Tank-silenced mature osteoclast is also increased. However, acid production of Tank-knockdown cells was not changed compared with control cells. IκBα phosphorylation is increased in tank-silenced cells, indicating that TANK may negatively regulate NF-κB activity in osteoclast. In conclusion, Tank, whose expression is increased during osteoclastogenesis, inhibits osteoclast formation, activity and survival, by regulating NF-κB activity and c-FLIP expression. Tank enrolls itself in a negative feedback loop in bone resorption. These results may provide means for therapeutic intervention in diseases of excessive bone resorption.

TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase*

PubMed Central

Wang, Wei; Huang, Xuan; Xin, Hong-Bo; Fu, Mingui; Xue, Aimin; Wu, Zhao-Hui

2015-01-01

DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination. PMID:25861989

Flg22-Triggered Immunity Negatively Regulates Key BR Biosynthetic Genes.

PubMed

Jiménez-Góngora, Tamara; Kim, Seong-Ki; Lozano-Durán, Rosa; Zipfel, Cyril

2015-01-01

In plants, activation of growth and activation of immunity are opposing processes that define a trade-off. In the past few years, the growth-promoting hormones brassinosteroids (BR) have emerged as negative regulators of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), promoting growth at the expense of defense. The crosstalk between BR and PTI signaling was described as negative and unidirectional, since activation of PTI does not affect several analyzed steps in the BR signaling pathway. In this work, we describe that activation of PTI by the bacterial PAMP flg22 results in the reduced expression of BR biosynthetic genes. This effect does not require BR perception or signaling, and occurs within 15 min of flg22 treatment. Since the described PTI-induced repression of gene expression may result in a reduction in BR biosynthesis, the crosstalk between PTI and BR could actually be negative and bidirectional, a possibility that should be taken into account when considering the interaction between these two pathways.

Neural correlates of reappraisal considering working memory capacity and cognitive flexibility.

PubMed

Zaehringer, Jenny; Falquez, Rosalux; Schubert, Anna-Lena; Nees, Frauke; Barnow, Sven

2018-01-09

Cognitive reappraisal of emotion is strongly related to long-term mental health. Therefore, the exploration of underlying cognitive and neural mechanisms has become an essential focus of research. Considering that reappraisal and executive functions rely on a similar brain network, the question arises whether behavioral differences in executive functions modulate neural activity during reappraisal. Using functional neuroimaging, the present study aimed to analyze the role of working memory capacity (WMC) and cognitive flexibility in brain activity during down-regulation of negative emotions by reappraisal in N = 20 healthy participants. Results suggests that WMC and cognitive flexibility were negatively correlated with prefrontal activity during reappraisal condition. Here, results also revealed a negative correlation between cognitive flexibility and amygdala activation. These findings provide first hints that (1) individuals with lower WMC and lower cognitive flexibility might need more higher-order cognitive neural resources in order to down-regulate negative emotions and (2) cognitive flexibility relates to emotional reactivity during reappraisal.

Sustained Expression of Negative Regulators of Myelination Protects Schwann Cells from Dysmyelination in a Charcot-Marie-Tooth 1B Mouse Model.

PubMed

Florio, Francesca; Ferri, Cinzia; Scapin, Cristina; Feltri, M Laura; Wrabetz, Lawrence; D'Antonio, Maurizio

2018-05-02

Schwann cell differentiation and myelination in the PNS are the result of fine-tuning of positive and negative transcriptional regulators. As myelination starts, negative regulators are downregulated, whereas positive ones are upregulated. Fully differentiated Schwann cells maintain an extraordinary plasticity and can transdifferentiate into "repair" Schwann cells after nerve injury. Reactivation of negative regulators of myelination is essential to generate repair Schwann cells. Negative regulators have also been implicated in demyelinating neuropathies, although their role in disease remains elusive. Here, we used a mouse model of Charcot-Marie-Tooth neuropathy type 1B (CMT1B), the P0S63del mouse characterized by ER stress and the activation of the unfolded protein response, to show that adult Schwann cells are in a partial differentiation state because they overexpress transcription factors that are normally expressed only before myelination. We provide evidence that two of these factors, Sox2 and Id2, act as negative regulators of myelination in vivo However, their sustained expression in neuropathy is protective because ablation of Sox2 or/and Id2 from S63del mice of both sexes results in worsening of the dysmyelinating phenotype. This is accompanied by increased levels of mutant P0 expression and exacerbation of ER stress, suggesting that limited differentiation may represent a novel adaptive mechanism through which Schwann cells counter the toxic effect of a mutant terminal differentiation protein. SIGNIFICANCE STATEMENT In many neuropathies, Schwann cells express high levels of early differentiation genes, but the significance of these altered expression remained unclear. Because many of these factors may act as negative regulators of myelination, it was suggested that their misexpression could contribute to dysmyelination. Here, we show that the transcription factors Sox2 and Id2 act as negative regulators of myelination in vivo , but that their sustained expression in Charcot-Marie-Tooth type 1B (CMT1B) represents an adaptive response activated by the Schwann cells to reduce mutant protein toxicity and prevent demyelination. Copyright © 2018 the authors 0270-6474/18/384275-14$15.00/0.

Sirt1 negatively regulates FcεRI-mediated mast cell activation through AMPK- and PTP1B-dependent processes.

PubMed

Li, Xian; Lee, Youn Ju; Jin, Fansi; Park, Young Na; Deng, Yifeng; Kang, Youra; Yang, Ju Hye; Chang, Jae-Hoon; Kim, Dong-Young; Kim, Jung-Ae; Chang, Young-Chae; Ko, Hyun-Jeong; Kim, Cheorl-Ho; Murakami, Makoto; Chang, Hyeun Wook

2017-07-25

Sirt1, a key regulator of metabolism and longevity, has recently been implicated in the regulation of allergic reactions, although the underlying mechanism remains unclear. Here we show that Sirt1 negatively regulates FcεRI-stimulated mast cell activation and anaphylaxis through two mutually regulated pathways involving AMP-activated protein kinase (AMPK) and protein tyrosine phosphatase 1B (PTP1B). Mast cell-specific knockout of Sirt1 dampened AMPK-dependent suppression of FcεRI signaling, thereby augmenting mast cell activation both in vitro and in vivo. Sirt1 inhibition of FcεRI signaling also involved an alternative component, PTP1B, which attenuated the inhibitory AMPK pathway and conversely enhanced the stimulatory Syk pathway, uncovering a novel role of this phosphatase. Moreover, a Sirt1 activator resveratrol stimulated the inhibitory AMPK axis, with reciprocal suppression of the stimulatory PTP1B/Syk axis, thus potently inhibiting anaphylaxis. Overall, our results provide a molecular explanation for the beneficial role of Sirt1 in allergy and underscore a potential application of Sirt1 activators as a new class of anti-allergic agents.

Inhibition of PDE4B suppresses inflammation by increasing expression of the deubiquitinase CYLD

PubMed Central

Komatsu, Kensei; Lee, Ji-Yun; Miyata, Masanori; Hyang Lim, Jae; Jono, Hirofumi; Koga, Tomoaki; Xu, Haidong; Yan, Chen; Kai, Hirofumi; Li, Jian-Dong

2013-01-01

The deubiquitinase CYLD acts as a key negative regulator to tightly control overactive inflammation. Most anti-inflammatory strategies have focused on directly targeting the positive regulator, which often results in significant side effects such as suppression of the host defence response. Here, we show that inhibition of phosphodiesterase 4B (PDE4B) markedly enhances upregulation of CYLD expression in response to bacteria, thereby suggesting that PDE4B acts as a negative regulator for CYLD. Interestingly, in Cyld-deficient mice, inhibition of PDE4B no longer suppresses inflammation. Moreover, PDE4B negatively regulates CYLD via specific activation of JNK2 but not JNK1. Importantly, ototopical post-inoculation administration of a PDE4 inhibitor suppresses inflammation in this animal model, thus demonstrating the therapeutic potential of targeting PDE4. These studies provide insights into how inflammation is tightly regulated via the inhibition of its negative regulator and may also lead to the development of new anti-inflammatory therapeutics that upregulate CYLD expression. PMID:23575688

Cell shape and negative links in regulatory motifs together control spatial information flow in signaling networks.

PubMed

Neves, Susana R; Tsokas, Panayiotis; Sarkar, Anamika; Grace, Elizabeth A; Rangamani, Padmini; Taubenfeld, Stephen M; Alberini, Cristina M; Schaff, James C; Blitzer, Robert D; Moraru, Ion I; Iyengar, Ravi

2008-05-16

The role of cell size and shape in controlling local intracellular signaling reactions, and how this spatial information originates and is propagated, is not well understood. We have used partial differential equations to model the flow of spatial information from the beta-adrenergic receptor to MAPK1,2 through the cAMP/PKA/B-Raf/MAPK1,2 network in neurons using real geometries. The numerical simulations indicated that cell shape controls the dynamics of local biochemical activity of signal-modulated negative regulators, such as phosphodiesterases and protein phosphatases within regulatory loops to determine the size of microdomains of activated signaling components. The model prediction that negative regulators control the flow of spatial information to downstream components was verified experimentally in rat hippocampal slices. These results suggest a mechanism by which cellular geometry, the presence of regulatory loops with negative regulators, and key reaction rates all together control spatial information transfer and microdomain characteristics within cells.

Sex differences in cognitive regulation of psychosocial achievement stress: brain and behavior.

PubMed

Kogler, Lydia; Gur, Ruben C; Derntl, Birgit

2015-03-01

Although cognitive regulation of emotion has been extensively examined, there is a lack of studies assessing cognitive regulation in stressful achievement situations. This study used functional magnetic resonance imaging in 23 females and 20 males to investigate cognitive downregulation of negative, stressful sensations during a frequently used psychosocial stress task. Additionally, subjective responses, cognitive regulation strategies, salivary cortisol, and skin conductance response were assessed. Subjective response supported the experimental manipulation by showing higher anger and negative affect ratings after stress regulation than after the mere exposure to stress. On a neural level, right middle frontal gyrus (MFG) and right superior temporal gyrus (STG) were more strongly activated during regulation than nonregulation, whereas the hippocampus was less activated during regulation. Sex differences were evident: after regulation females expressed higher subjective stress ratings than males, and these ratings were associated with right hippocampal activation. In the nonregulation block, females showed greater activation of the left amygdala and the right STG during stress than males while males recruited the putamen more robustly in this condition. Thus, cognitive regulation of stressful achievement situations seems to induce additional stress, to recruit regions implicated in attention integration and working memory and to deactivate memory retrieval. Stress itself is associated with greater activation of limbic as well as attention areas in females than males. Additionally, activation of the memory system during cognitive regulation of stress is associated with greater perceived stress in females. Sex differences in cognitive regulation strategies merit further investigation that can guide sex sensitive interventions for stress-associated disorders. © 2014 Wiley Periodicals, Inc.

Orphan nuclear receptor Nur77 is a novel negative regulator of endothelin-1 expression in vascular endothelial cells.

PubMed

Qin, Qing; Chen, Ming; Yi, Bing; You, Xiaohua; Yang, Ping; Sun, Jianxin

2014-12-01

Endothelin-1 (ET-1) produced by vascular endothelial cells plays essential roles in the regulation of vascular tone and development of cardiovascular diseases. The objective of this study is to identify novel regulators implicated in the regulation of ET-1 expression in vascular endothelial cells (ECs). By using quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), we show that either ectopic expression of orphan nuclear receptor Nur77 or pharmacological activation of Nur77 by 6-mercaptopurine (6-MP) substantially inhibits ET-1 expression in human umbilical vein endothelial cells (HUVECs), under both basal and thrombin-stimulated conditions. Furthermore, thrombin-stimulated ET expression is significantly augmented in both Nur77 knockdown ECs and aort from Nur77 knockout mice, suggesting that Nur77 is a negative regulator of ET-1 expression. Inhibition of ET-1 expression by Nur77 occurs at gene transcriptional levels, since Nur77 potently inhibits ET-1 promoter activity, without affecting ET-1 mRNA stability. As shown in electrophoretic mobility shift assay (EMSA), Nur77 overexpression markedly inhibits both basal and thrombin-stimulated transcriptional activity of AP-1. Mechanistically, we demonstrate that Nur77 specially interacts with c-Jun and inhibits AP-1 dependent c-Jun promoter activity, which leads to a decreased expression of c-Jun, a critical component involved in both AP-1 transcriptional activity and ET-1 expression in ECs. These findings demonstrate that Nur77 is a novel negative regulator of ET-1 expression in vascular ECs through an inhibitory interaction with the c-Jun/AP-1 pathway. Activation of Nur77 may represent a useful therapeutic strategy for preventing certain cardiovascular diseases, such as atherosclerosis and pulmonary artery hypertension. Copyright © 2014 Elsevier Ltd. All rights reserved.

Self-Regulation and Implicit Attitudes Toward Physical Activity Influence Exercise Behavior.

PubMed

Padin, Avelina C; Emery, Charles F; Vasey, Michael; Kiecolt-Glaser, Janice K

2017-08-01

Dual-process models of health behavior posit that implicit and explicit attitudes independently drive healthy behaviors. Prior evidence indicates that implicit attitudes may be related to weekly physical activity (PA) levels, but the extent to which self-regulation attenuates this link remains unknown. This study examined the associations between implicit attitudes and self-reported PA during leisure time among 150 highly active young adults and evaluated the extent to which effortful control (one aspect of self-regulation) moderated this relationship. Results indicated that implicit attitudes toward exercise were unrelated to average workout length among individuals with higher effortful control. However, those with lower effortful control and more negative implicit attitudes reported shorter average exercise sessions compared with those with more positive attitudes. Implicit and explicit attitudes were unrelated to total weekly PA. A combination of poorer self-regulation and negative implicit attitudes may leave individuals vulnerable to mental and physical health consequences of low PA.

The Putative PAX8/PPARγ Fusion Oncoprotein Exhibits Partial Tumor Suppressor Activity through Up-Regulation of Micro-RNA-122 and Dominant-Negative PPARγ Activity.

PubMed

Reddi, Honey V; Madde, Pranathi; Milosevic, Dragana; Hackbarth, Jennifer S; Algeciras-Schimnich, Alicia; McIver, Bryan; Grebe, Stefan K G; Eberhardt, Norman L

2011-01-01

In vitro studies have demonstrated that the PAX8/PPARγ fusion protein (PPFP), which occurs frequently in follicular thyroid carcinomas (FTC), exhibits oncogenic activity. However, paradoxically, a meta-analysis of extant tumor outcome studies indicates that 68% of FTC-expressing PPFP are minimally invasive compared to only 32% of those lacking PPFP (χ(2) = 6.86, P = 0.008), suggesting that PPFP favorably impacts FTC outcomes. In studies designed to distinguish benign thyroid neoplasms from thyroid carcinomas, the previously identified tumor suppressor miR-122, a major liver micro-RNA (miR) that is decreased in hepatocellular carcinoma, was increased 8.9-fold (P < 0.05) in all FTC versus normal, 9.2-fold in FTC versus FA (P < 0.05), and 16.8-fold (P < 0.001) in FTC + PPFP versus FTC - PPFP. Constitutive expression of PPFP in the FTC-derived cell line WRO (WRO-PPFP) caused a 5-fold increase of miR-122 expression (P < 0.05) and a striking 5.1-fold reduction (P < 0.0001) in tumor progression compared to WRO-vector cells in a mouse xenograft model. Constitutive expression of either miR-122 or a dominant-negative PPARγ mutant in WRO cells was less effective than PPFP at inhibiting xenograft tumor progression (1.8-fold [P < 0.001] and 1.7-fold [P < 0.03], respectively). PPFP-induced up-regulation of miR-122 expression was independent of its known dominant-negative PPARγ activity. Up-regulation of miR-122 negatively regulates ADAM-17, a known downstream target, in thyroid cells, suggesting an antiangiogenic mechanism in thyroid carcinoma. This latter inference is directly supported by reduced CD-31 expression in WRO xenografts expressing PPFP, miR-122, and DN-PPARγ. We conclude that, in addition to its apparent oncogenic potential in vitro, PPFP exhibits paradoxical tumor suppressor activity in vivo, mediated by multiple mechanisms including up-regulation of miR-122 and dominant-negative inhibition of PPARγ activity.

Emotional reactivity and emotion regulation among adults with a history of self-harm: laboratory self-report and functional MRI evidence.

PubMed

Davis, Tchiki S; Mauss, Iris B; Lumian, Daniel; Troy, Allison S; Shallcross, Amanda J; Zarolia, Paree; Ford, Brett Q; McRae, Kateri

2014-08-01

Intentionally hurting one's body (deliberate self-harm; DSH) is theorized to be associated with high negative emotional reactivity and poor emotion regulation ability. However, little research has assessed the relationship between these potential risk factors and DSH using laboratory measures. Therefore, we conducted 2 studies using laboratory measures of negative emotional reactivity and emotion regulation ability. Study 1 assessed self-reported negative emotions during a sad film clip (reactivity) and during a sad film clip for which participants were instructed to use reappraisal (regulation). Those with a history of DSH were compared with 2 control groups without a history of DSH matched on key demographics: 1 healthy group low in depression and anxiety symptoms and 1 group matched to the DSH group on depression and anxiety symptoms. Study 2 extended Study 1 by assessing neural responding to negative images (reactivity) and negative images for which participants were instructed to use reappraisal (regulation). Those with a history of DSH were compared with a control group matched to the DSH group on demographics, depression, and anxiety symptoms. Compared with control groups, participants with a history of DSH did not exhibit greater negative emotional reactivity but did exhibit lower ability to regulate emotion with reappraisal (greater self-reported negative emotions in Study 1 and greater amygdala activation in Study 2 during regulation). These results suggest that poor emotion regulation ability, but not necessarily greater negative emotional reactivity, is a correlate of and may be a risk factor for DSH, even when controlling for mood disorder symptoms. (c) 2014 APA, all rights reserved.

Emotional Reactivity and Emotion Regulation among Adults with a History of Self-Harm: Laboratory Self-Report and fMRI Evidence

PubMed Central

Davis, Tchiki S.; Mauss, Iris B.; Lumian, Daniel; Troy, Allison S.; Shallcross, Amanda J.; Zarolia, Paree; Ford, Brett Q.; McRae, Kateri

2014-01-01

Intentionally hurting one’s own body (deliberate self-harm; DSH) is theorized to be associated with high negative emotional reactivity and poor emotion regulation ability. However, little research has assessed the relationship between these potential risk factors and DSH using laboratory measures. Therefore, we conducted two studies using laboratory measures of negative emotional reactivity and emotion regulation ability. Study 1 assessed self-reported negative emotions during a sad film clip (Reactivity) and during a sad film clip for which participants were instructed to use reappraisal (Regulation). Those with a history of DSH were compared to two control groups without a history of DSH matched on key demographics: one healthy group low in depression and anxiety symptoms and one group matched to the DSH group on depression and anxiety symptoms. Study 2 extended Study 1 by assessing neural responding to negative images (Reactivity) and negative images for which participants were instructed to use reappraisal (Regulation). Those with a history of DSH were compared to a control group matched to the DSH group on demographics, depression, and anxiety symptoms. Compared to control groups, participants with a history of DSH did not exhibit greater negative emotional reactivity but did exhibit lower ability to regulate emotion with reappraisal (greater self-reported negative emotions in Study 1 and greater amygdala activation in Study 2 during regulation). These results suggest that poor emotion regulation ability, but not necessarily greater negative emotional reactivity, is a correlate of and may be a risk factor for DSH, even when controlling for mood disorder symptoms. PMID:24865373

Adrenocortical Activity and Emotion Regulation.

ERIC Educational Resources Information Center

Stansbury, Kathy; Gunnar, Megan R.

1994-01-01

This essay argues that the activity of the hypothalamic-pituitary-adrenocortical (HPA) system does not appear to be related to emotion regulation processes in children, although individual differences in emotion processes related to negative emotion temperaments appear to be associated with individual differences in HPA reactivity among normally…

Costimulation dependent expression of miR-214 increases the ability of T cells to proliferate by targeting Pten

PubMed Central

Jindra, Peter T.; Bagley, Jessamyn; Godwin, Jonathan G.; Iacomini, John

2010-01-01

T cell activation requires signaling through the T cell receptor (TCR) and costimulatory molecules such as CD28. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post transcriptionally and are also known to be involved in lymphocyte development and function. Here we set out to examine potential roles of miRNAs in T cell activation by using genome-wide expression profiling to identify miRNAs differentially regulated following T cell activation. One of the miRNAs up-regulated after T cell activation, miR-214, was predicted to be capable of targeting Pten based on bioinformatics and reports suggesting that it targets Pten in ovarian tumor cells. Up-regulation of miR-214 in T cells inversely correlated with PTEN levels. In vivo, transcripts containing the 3' untranslated region (3' UTR) of Pten including the miR-214 target sequence were negatively regulated after T cell activation, and forced expression of miR-214 in T cells led to increased proliferation after stimulation. Blocking CD28 signaling in vivo prevented miR-214 up-regulation in alloreactive T cells. Stimulation of T cells through the TCR alone was not sufficient to result in upregulation of miR-214. Thus, costimulation dependent up-regulation of miR-214 promotes T cell activation by targeting the negative regulator Pten. Thus, the requirement for T cell costimulation is in part related to its ability to regulate expression of miRNAs that control T cell activation. PMID:20548023

Association of Lyn kinase with membrane rafts determines its negative influence on LPS-induced signaling

PubMed Central

Borzęcka-Solarz, Kinga; Dembińska, Justyna; Hromada-Judycka, Aneta; Traczyk, Gabriela; Ciesielska, Anna; Ziemlińska, Ewelina; Świątkowska, Anna; Kwiatkowska, Katarzyna

2017-01-01

Lipopolysaccharide (LPS) is the component of Gram-negative bacteria that activates Toll-like receptor 4 (TLR4) to trigger proinflammatory responses. We examined the involvement of Lyn tyrosine kinase in TLR4 signaling of macrophages, distinguishing its catalytic activity and intermolecular interactions. For this, a series of Lyn-GFP constructs bearing point mutations in particular domains of Lyn were overexpressed in RAW264 macrophage-like cells or murine peritoneal macrophages, and their influence on LPS-induced responses was analyzed. Overproduction of wild-type or constitutively active Lyn inhibited production of TNF-α and CCL5/RANTES cytokines and down-regulated the activity of NFκB and IRF3 transcription factors in RAW264 cells. The negative influence of Lyn was nullified by point mutations of Lyn catalytic domain or Src homology 2 (SH2) or SH3 domains or of the cysteine residue that undergoes LPS-induced palmitoylation. Depending on the cell type, overproduction of those mutant forms of Lyn could even up-regulate LPS-induced responses, and this effect was reproduced by silencing of endogenous Lyn expression. Simultaneously, the Lyn mutations blocked its LPS-induced accumulation in the raft fraction of RAW264 cells. These data indicate that palmitoylation, SH2- and SH3-mediated intermolecular interactions, and the catalytic activity of Lyn are required for its accumulation in rafts, thereby determining the negative regulation of TLR4 signaling. PMID:28228554

TRPC5-eNOS Axis Negatively Regulates ATP-Induced Cardiomyocyte Hypertrophy.

PubMed

Sunggip, Caroline; Shimoda, Kakeru; Oda, Sayaka; Tanaka, Tomohiro; Nishiyama, Kazuhiro; Mangmool, Supachoke; Nishimura, Akiyuki; Numaga-Tomita, Takuro; Nishida, Motohiro

2018-01-01

Cardiac hypertrophy, induced by neurohumoral factors, including angiotensin II and endothelin-1, is a major predisposing factor for heart failure. These ligands can induce hypertrophic growth of neonatal rat cardiomyocytes (NRCMs) mainly through Ca 2+ -dependent calcineurin/nuclear factor of activated T cell (NFAT) signaling pathways activated by diacylglycerol-activated transient receptor potential canonical 3 and 6 (TRPC3/6) heteromultimer channels. Although extracellular nucleotide, adenosine 5'-triphosphate (ATP), is also known as most potent Ca 2+ -mobilizing ligand that acts on purinergic receptors, ATP never induces cardiomyocyte hypertrophy. Here we show that ATP-induced production of nitric oxide (NO) negatively regulates hypertrophic signaling mediated by TRPC3/6 channels in NRCMs. Pharmacological inhibition of NO synthase (NOS) potentiated ATP-induced increases in NFAT activity, protein synthesis, and transcriptional activity of brain natriuretic peptide. ATP significantly increased NO production and protein kinase G (PKG) activity compared to angiotensin II and endothelin-1. We found that ATP-induced Ca 2+ signaling requires inositol 1,4,5-trisphosphate (IP 3 ) receptor activation. Interestingly, inhibition of TRPC5, but not TRPC6 attenuated ATP-induced activation of Ca 2+ /NFAT-dependent signaling. As inhibition of TRPC5 attenuates ATP-stimulated NOS activation, these results suggest that NO-cGMP-PKG axis activated by IP 3 -mediated TRPC5 channels underlies negative regulation of TRPC3/6-dependent hypertrophic signaling induced by ATP stimulation.

Loss of PTB or Negative Regulation of Notch mRNA Reveals Distinct Zones of Notch and Actin Protein Accumulation in Drosophila Embryo

PubMed Central

Wesley, Cedric S.; Guo, Heng; Chaudhry, Kanita A.; Thali, Markus J.; Yin, Jerry C.; Clason, Todd; Wesley, Umadevi V.

2011-01-01

Polypyrimidine Tract Binding (PTB) protein is a regulator of mRNA processing and translation. Genetic screens and studies of wing and bristle development during the post-embryonic stages of Drosophila suggest that it is a negative regulator of the Notch pathway. How PTB regulates the Notch pathway is unknown. Our studies of Drosophila embryogenesis indicate that (1) the Notch mRNA is a potential target of PTB, (2) PTB and Notch functions in the dorso-lateral regions of the Drosophila embryo are linked to actin regulation but not their functions in the ventral region, and (3) the actin-related Notch activity in the dorso-lateral regions might require a Notch activity at or near the cell surface that is different from the nuclear Notch activity involved in cell fate specification in the ventral region. These data raise the possibility that the Drosophila embryo is divided into zones of different PTB and Notch activities based on whether or not they are linked to actin regulation. They also provide clues to the almost forgotten role of Notch in cell adhesion and reveal a role for the Notch pathway in cell fusions. PMID:21750738

Macrophage Pro-Inflammatory Response to Francisella novicida Infection Is Regulated by SHIP

PubMed Central

Parsa, Kishore V. L; Ganesan, Latha P; Rajaram, Murugesan V. S; Gavrilin, Mikhail A; Balagopal, Ashwin; Mohapatra, Nrusingh P; Wewers, Mark D; Schlesinger, Larry S; Gunn, John S; Tridandapani, Susheela

2006-01-01

Francisella tularensis, a Gram-negative facultative intracellular pathogen infecting principally macrophages and monocytes, is the etiological agent of tularemia. Macrophage responses to F. tularensis infection include the production of pro-inflammatory cytokines such as interleukin (IL)-12, which is critical for immunity against infection. Molecular mechanisms regulating production of these inflammatory mediators are poorly understood. Herein we report that the SH2 domain-containing inositol phosphatase (SHIP) is phosphorylated upon infection of primary murine macrophages with the genetically related F. novicida, and negatively regulates F. novicida–induced cytokine production. Analyses of the molecular details revealed that in addition to activating the MAP kinases, F. novicida infection also activated the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in these cells. Interestingly, SHIP-deficient macrophages displayed enhanced Akt activation upon F. novicida infection, suggesting elevated PI3K-dependent activation pathways in absence of SHIP. Inhibition of PI3K/Akt resulted in suppression of F. novicida–induced cytokine production through the inhibition of NFκB. Consistently, macrophages lacking SHIP displayed enhanced NFκB-driven gene transcription, whereas overexpression of SHIP led to decreased NFκB activation. Thus, we propose that SHIP negatively regulates F. novicida–induced inflammatory cytokine response by antagonizing the PI3K/Akt pathway and suppressing NFκB-mediated gene transcription. A detailed analysis of phosphoinositide signaling may provide valuable clues for better understanding the pathogenesis of tularemia. PMID:16848641

Essential Role of TEA Domain Transcription Factors in the Negative Regulation of the MYH 7 Gene by Thyroid Hormone and Its Receptors

PubMed Central

Iwaki, Hiroyuki; Sasaki, Shigekazu; Matsushita, Akio; Ohba, Kenji; Matsunaga, Hideyuki; Misawa, Hiroko; Oki, Yutaka; Ishizuka, Keiko; Nakamura, Hirotoshi; Suda, Takafumi

2014-01-01

MYH7 (also referred to as cardiac myosin heavy chain β) gene expression is known to be repressed by thyroid hormone (T3). However, the molecular mechanism by which T3 inhibits the transcription of its target genes (negative regulation) remains to be clarified, whereas those of transcriptional activation by T3 (positive regulation) have been elucidated in detail. Two MCAT (muscle C, A, and T) sites and an A/T-rich region in the MYH7 gene have been shown to play a critical role in the expression of this gene and are known to be recognized by the TEAD/TEF family of transcription factors (TEADs). Using a reconstitution system with CV-1 cells, which has been utilized in the analysis of positive as well as negative regulation, we demonstrate that both T3 receptor (TR) β1 and α1 inhibit TEAD-dependent activation of the MYH7 promoter in a T3 dose-dependent manner. TRβ1 bound with GC-1, a TRβ-selective T3 analog, also repressed TEAD-induced activity. Although T3-dependent inhibition required the DNA-binding domain (DBD) of TRβ1, it remained after the putative negative T3-responsive elements were mutated. A co-immunoprecipitation study demonstrated the in vivo association of TRβ1 with TEAD-1, and the interaction surfaces were mapped to the DBD of the TRβ1 and TEA domains of TEAD-1, both of which are highly conserved among TRs and TEADs, respectively. The importance of TEADs in MYH7 expression was also validated with RNA interference using rat embryonic cardiomyocyte H9c2 cells. These results indicate that T3-bound TRs interfere with transactivation by TEADs via protein-protein interactions, resulting in the negative regulation of MYH7 promoter activity. PMID:24781449

BRAFV600E negatively regulates the AKT pathway in melanoma cell lines.

PubMed

Chen, Brenden; Tardell, Christine; Higgins, Brian; Packman, Kathryn; Boylan, John F; Niu, Huifeng

2012-01-01

Cross-feedback activation of MAPK and AKT pathways is implicated as a resistance mechanism for cancer therapeutic agents targeting either RAF/MEK or PI3K/AKT/mTOR. It is thus important to have a better understanding of the molecular resistance mechanisms to improve patient survival benefit from these agents. Here we show that BRAFV600E is a negative regulator of the AKT pathway. Expression of BRAFV600E in NIH3T3 cells significantly suppresses MEK inhibitor (RG7167) or mTORC1 inhibitor (rapamycin) induced AKT phosphorylation (pAKT) and downstream signal activation. Treatment-induced pAKT elevation is found in BRAF wild type melanoma cells but not in a subset of melanoma cell lines harboring BRAFV600E. Knock-down of BRAFV600E in these melanoma cells elevates basal pAKT and downstream signals, whereas knock-down of CRAF, MEK1/2 or ERK1/2 or treatment with a BRAF inhibitor have no impact on pAKT. Mechanistically, we show that BRAFV600E interacts with rictor complex (mTORC2) and regulates pAKT through mTORC2. BRAFV600E is identified in mTORC2 after immunoprecipitation of rictor. Knock-down of rictor abrogates BRAFV600E depletion induced pAKT. Knock-down of BRAFV600E enhances cellular enzyme activity of mTORC2. Aberrant activation of AKT pathway by PTEN loss appears to override the negative impact of BRAFV600E on pAKT. Taken together, our findings suggest that in a subset of BRAFV600E melanoma cells, BRAFV600E negatively regulates AKT pathway in a rictor-dependent, MEK/ERK and BRAF kinase-independent manner. Our study reveals a novel molecular mechanism underlying the regulation of feedback loops between the MAPK and AKT pathways.

Habitual emotion regulation strategies and depressive symptoms in healthy subjects predict fMRI brain activation patterns related to major depression.

PubMed

Abler, Birgit; Hofer, Christian; Walter, Henrik; Erk, Susanne; Hoffmann, Holger; Traue, Harald C; Kessler, Henrik

2010-08-30

The response-focused emotion regulation style 'Expressive suppression' has been associated with symptoms of lower psychological well-being and increased function magnetic resonance imaging (fMRI) activation of the sublenticular extended amygdala (SLEA) in patients with major depression. Extending prior studies on active emotion regulation, we were interested in effects of habitual emotion regulation on neurobiology. Thirty subjects with either relatively high or low suppression scores as assessed with the Emotion Regulation Questionnaire without symptoms of clinical depression participated in the study. They were instructed to expect and then perceive emotionally unpleasant, pleasant or neutral stimuli selected from the International Affective Picture System that were announced by a congruent cue during fMRI. In the subjects with high suppression scores, decreased activation of the orbital medial prefrontal cortex (oMFC) when expecting negative pictures and increased activation of the SLEA upon presentation of neutral stimuli were found. Subclinical depression ratings independently of suppression scores in the healthy subjects were positively correlated with brain activation in the SLEA when expecting negative pictures. SLEA hyperactivity may represent an emotional responsivity that involves less successful habitual emotion regulation and a tendency to depressed mood in healthy subjects, as shown in patients with major depression. Decreased anticipatory oMFC activation may parallel a lack of antecedent emotion regulation in subjects with high suppression scores, representing another neurobiological predictor of lower mental well-being. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Modulating Emotional Experience Using Electrical Stimulation of the Medial-Prefrontal Cortex: A Preliminary tDCS-fMRI Study.

PubMed

Abend, Rany; Sar-El, Roy; Gonen, Tal; Jalon, Itamar; Vaisvaser, Sharon; Bar-Haim, Yair; Hendler, Talma

2018-05-09

Implicit regulation of emotions involves medial-prefrontal cortex (mPFC) regions exerting regulatory control over limbic structures. Diminished regulation relates to aberrant mPFC functionality and psychopathology. Establishing means of modulating mPFC functionality could benefit research on emotion and its dysregulation. Here, we tested the capacity of transcranial direct current stimulation (tDCS) targeting mPFC to modulate subjective emotional states by facilitating implicit emotion regulation. Stimulation was applied concurrently with functional magnetic resonance imaging to validate its neurobehavioral effect. Sixteen participants were each scanned twice, counterbalancing active and sham tDCS application, while undergoing negative mood induction (clips featuring negative vs. neutral contents). Effects of stimulation on emotional experience were assessed using subjective and neural measures. Subjectively, active stimulation led to significant reduction in reported intensity of experienced emotions to negatively valenced (p = 0.005) clips but not to neutral clips (p > 0.99). Active stimulation further mitigated a rise in stress levels from pre- to post-induction (sham: p = 0.004; active: p = 0.15). Neurally, stimulation increased activation in mPFC regions associated with implicit emotion regulation (ventromedial-prefrontal cortex; subgenual anterior-cingulate cortex, sgACC), and in ventral striatum, a core limbic structure (all ps < 0.05). Stimulation also altered functional connectivity (assessed using whole-brain psycho-physiological interaction) between these regions, and with additional limbic regions. Stimulation-induced sgACC activation correlated with reported emotion intensity and depressive symptoms (rs > 0.64, ps < 0.018), suggesting individual differences in stimulation responsivity. Results of this study indicate the potential capacity of tDCS to facilitate brain activation in mPFC regions underlying implicit regulation of emotion and accordingly modulate subjective emotional experiences. © 2018 International Neuromodulation Society.

The discovery of a reciprocal relationship between tyrosine-kinase signaling and cullin neddylation.

PubMed

Friend, Samantha F; Peterson, Lisa K; Treacy, Eric; Stefanski, Adrianne L; Sosinowski, Tomasz; Pennock, Nathan D; Berger, Allison J; Winn, Virginia D; Dragone, Leonard L

2013-01-01

While neddylation is known to activate cullin (CUL)-RING ubiquitin ligases (CRLs), its role in regulating T cell signaling is poorly understood. Using the investigational NEDD8 activating enzyme (NAE) inhibitor, MLN4924, we found that neddylation negatively regulates T cell receptor (TCR) signaling, as its inhibition increases IL-2 production, T cell proliferation and Treg development in vitro. We also discovered that loss of CUL neddylation occurs upon TCR signaling, and CRLs negatively regulate IL-2 production. Additionally, we found that tyrosine kinase signaling leads to CUL deneddylation in multiple cell types. These studies indicate that CUL neddylation is a global regulatory mechanism for tyrosine kinase signaling.

Peroxisome proliferator-activated receptor {alpha} agonist-induced down-regulation of hepatic glucocorticoid receptor expression in SD rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Xiang; Li Ming; Sun Weiping

2008-04-18

It was reported that glucocorticoid production was inhibited by fenofibrate through suppression of type-1 11{beta}-hydroxysteroid dehydrogenase gene expression in liver. The inhibition might be a negative-feedback regulation of glucocorticoid receptor (GR) activity by peroxisome proliferator-activated receptor alpha (PPAR{alpha}), which is quickly induced by glucocorticoid in the liver. However, it is not clear if GR expression is changed by fenofibrate-induced PPAR{alpha} activation. In this study, we tested this possibility in the liver of Sprague-Dawley rats. GR expression was reduced by fenofibrate in a time- and does-dependent manner. The inhibition was observed in liver, but not in fat and muscle. The corticosteronemore » level in the blood was increased significantly by fenofibrate. These effects of fenofibrate were abolished by PPAR{alpha} inhibitor MK886, suggesting that fenofibrate activated through PPAR{alpha}. In conclusion, inhibition of GR expression may represent a new molecular mechanism for the negative feedback regulation of GR activity by PPAR{alpha}.« less

PprM is necessary for up-regulation of katE1, encoding the major catalase of Deinococcus radiodurans, under unstressed culture conditions.

PubMed

Jeong, Sun-Wook; Seo, Ho Seong; Kim, Min-Kyu; Choi, Jong-Il; Lim, Heon-Man; Lim, Sangyong

2016-06-01

Deinococcus radiodurans is a poly-extremophilic organism, capable of tolerating a wide variety of different stresses, such as gamma/ultraviolet radiation, desiccation, and oxidative stress. PprM, a cold shock protein homolog, is involved in the radiation resistance of D. radiodurans, but its role in the oxidative stress response has not been investigated. In this study, we investigated the effect of pprM mutation on catalase gene expression. pprM disruption decreased the mRNA and protein levels of KatE1, which is the major catalase in D. radiodurans, under normal culture conditions. A pprM mutant strain (pprM MT) exhibited decreased catalase activity, and its resistance to hydrogen peroxide (H2O2) decreased accordingly compared with that of the wild-type strain. We confirmed that RecG helicase negatively regulates katE1 under normal culture conditions. Among katE1 transcriptional regulators, the positive regulator drRRA was not altered in pprM (-), while the negative regulators perR, dtxR, and recG were activated more than 2.5-fold in pprM MT. These findings suggest that PprM is necessary for KatE1 production under normal culture conditions by down-regulation of katE1 negative regulators.

JIP1-Mediated JNK Activation Negatively Regulates Synaptic Plasticity and Spatial Memory.

PubMed

Morel, Caroline; Sherrin, Tessi; Kennedy, Norman J; Forest, Kelly H; Avcioglu Barutcu, Seda; Robles, Michael; Carpenter-Hyland, Ezekiel; Alfulaij, Naghum; Standen, Claire L; Nichols, Robert A; Benveniste, Morris; Davis, Roger J; Todorovic, Cedomir

2018-04-11

The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JNK-interacting protein 1 (JIP1) scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDAR currents, increased NMDAR-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation. The JIP1 mutant mice also displayed improved hippocampus-dependent spatial memory and enhanced associative fear conditioning. These results were confirmed using a second JIP1 mutant mouse model that suppresses JNK activity. Together, these observations establish that JIP1-mediated JNK activation contributes to the regulation of hippocampus-dependent, NMDAR-mediated synaptic plasticity and learning. SIGNIFICANCE STATEMENT The results of this study demonstrate that c-Jun N-terminal kinase (JNK) activation induced by the JNK-interacting protein 1 (JIP1) scaffold protein negatively regulates the threshold for induction of long-term synaptic plasticity through the NMDA-type glutamate receptor. This change in plasticity threshold influences learning. Indeed, mice with defects in JIP1-mediated JNK activation display enhanced memory in hippocampus-dependent tasks, such as contextual fear conditioning and Morris water maze, indicating that JIP1-JNK constrains spatial memory. This study identifies JIP1-mediated JNK activation as a novel molecular pathway that negatively regulates NMDAR-dependent synaptic plasticity and memory. Copyright © 2018 the authors 0270-6474/18/383708-21$15.00/0.

Both sides of the same coin: Rac1 splicing regulating by EGF signaling.

PubMed

Fu, Xiang-Dong

2017-04-01

EGF, a well-studied mitogen for cancer cells, is revealed to induce an E3 ubiquitin ligase adaptor SPSB1, which recruits the Elongin B/C-Collin complex to trigger ubiquitylation of the negative splicing regulator hnRNP A1. This event is synergized with EGF-activated SR proteins to alter alternative splicing of a key small GTPase Rac1 to enhance cell migration, highlighting converging EGF signals on both negative and positive splicing regulators to jointly promote a key cancer pathway.

PTEN, a negative regulator of PI3K/Akt signaling, sustains brain stem cardiovascular regulation during mevinphos intoxication.

PubMed

Tsai, Ching-Yi; Wu, Jacqueline C C; Fang, Chi; Chang, Alice Y W

2017-09-01

Activation of PI3K/Akt signaling, leading to upregulation of nitric oxide synthase II (NOS II)/peroxynitrite cascade in the rostral ventrolateral medulla (RVLM), the brain stem site that maintains blood pressure and sympathetic vasomotor tone, underpins cardiovascular depression induced by the organophosphate pesticide mevinphos. By exhibiting dual-specificity protein- and lipid-phosphatase activity, phosphatase and tensin homolog (PTEN) directly antagonizes the PI3K/Akt signaling by dephosphorylation of phosphatidylinositol-3,4,5-trisphosphate, the lipid product of PI3K. Based on the guiding hypothesis that PTEN may sustain brain stem cardiovascular regulation during mevinphos intoxication as a negative regulator of PI3K/Akt signaling in the RVLM, we aimed in this study to clarify the mechanistic role of PTEN in mevinphos-induced circulatory depression. Microinjection bilaterally of mevinphos (10 nmol) into the RVLM of anesthetized Sprague-Dawley rats induced a progressive hypotension and a decrease in baroreflex-mediated sympathetic vasomotor tone. There was progressive augmentation in PTEN activity as reflected by a decrease in the oxidized form of PTEN in the RVLM during mevinhpos intoxication, without significant changes in the mRNA or protein level of PTEN. Loss-of-function manipulations of PTEN in the RVLM by immunoneutralization, pharmacological blockade or siRNA pretreatment significantly potentiated the increase in Akt activity or NOS II/peroxynitrite cascade in the RVLM, enhanced the elicited hypotension and exacerbated the already reduced baroreflex-mediated sympathetic vasomotor tone. We conclude that augmented PTEN activity via a decrease of its oxidized form in the RVLM sustains brain stem cardiovascular regulation during mevinphos intoxication via downregulation of the NOS II/peroxynitrite cascade as a negative regulator of PI3K/Akt signaling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transcription through enhancers suppresses their activity in Drosophila

PubMed Central

2013-01-01

Background Enhancer elements determine the level of target gene transcription in a tissue-specific manner, providing for individual patterns of gene expression in different cells. Knowledge of the mechanisms controlling enhancer action is crucial for understanding global regulation of transcription. In particular, enhancers are often localized within transcribed regions of the genome. A number of experiments suggest that transcription can have both positive and negative effects on regulatory elements. In this study, we performed direct tests for the effect of transcription on enhancer activity. Results Using a transgenic reporter system, we investigated the relationship between the presence of pass-through transcription and the activity of Drosophila enhancers controlling the expression of the white and yellow genes. The results show that transcription from different promoters affects the activity of enhancers, counteracting their ability to activate the target genes. As expected, the presence of a transcriptional terminator between the inhibiting promoter and the affected enhancer strongly reduces the suppression. Moreover, transcription leads to dislodging of the Zeste protein that is responsible for the enhancer-dependent regulation of the white gene, suggesting a 'transcription interference’ mechanism for this regulation. Conclusions Our findings suggest a role for pass-through transcription in negative regulation of enhancer activity. PMID:24279291

Facial expression primes and implicit regulation of negative emotion.

PubMed

Yoon, HeungSik; Kim, Shin Ah; Kim, Sang Hee

2015-06-17

An individual's responses to emotional information are influenced not only by the emotional quality of the information, but also by the context in which the information is presented. We hypothesized that facial expressions of happiness and anger would serve as primes to modulate subjective and neural responses to subsequently presented negative information. To test this hypothesis, we conducted a functional MRI study in which the brains of healthy adults were scanned while they performed an emotion-rating task. During the task, participants viewed a series of negative and neutral photos, one at a time; each photo was presented after a picture showing a face expressing a happy, angry, or neutral emotion. Brain imaging results showed that compared with neutral primes, happy facial primes increased activation during negative emotion in the dorsal anterior cingulated cortex and the right ventrolateral prefrontal cortex, which are typically implicated in conflict detection and implicit emotion control, respectively. Conversely, relative to neutral primes, angry primes activated the right middle temporal gyrus and the left supramarginal gyrus during the experience of negative emotion. Activity in the amygdala in response to negative emotion was marginally reduced after exposure to happy primes compared with angry primes. Relative to neutral primes, angry facial primes increased the subjectively experienced intensity of negative emotion. The current study results suggest that prior exposure to facial expressions of emotions modulates the subsequent experience of negative emotion by implicitly activating the emotion-regulation system.

Negative mood regulation expectancies moderate the relationship between psychological abuse and avoidant coping.

PubMed

Shepherd-McMullen, Cassandra; Mearns, Jack; Stokes, Julie E; Mechanic, Mindy B

2015-05-01

This study explored the relationships among psychological abuse, attitudes about intimate partner violence (IPV), negative mood regulation expectancies (NMRE), and coping. Participants were 126 female college students in dating, cohabitating, or married relationships within the previous year. In one single session, they completed self-report scales measuring IPV, NMRE, and coping. Results indicated that women reporting higher levels of psychological abuse reported less negative attitudes toward IPV, engaged in less-active coping responses, and had lower NMRE. Psychological abuse was a significant predictor of avoidant coping, while NMRE significantly predicted both active and avoidant coping. In addition, the interaction of NMRE × Psychological abuse added incremental prediction of avoidant coping. Implications for research and practice are discussed. © The Author(s) 2014.

CLAVATA1 Dominant-Negative Alleles Reveal Functional Overlap between Multiple Receptor Kinases That Regulate Meristem and Organ Development

PubMed Central

Diévart, Anne; Dalal, Monica; Tax, Frans E.; Lacey, Alexzandria D.; Huttly, Alison; Li, Jianming; Clark, Steven E.

2003-01-01

The CLAVATA1 (CLV1) receptor kinase controls stem cell number and differentiation at the Arabidopsis shoot and flower meristems. Other components of the CLV1 signaling pathway include the secreted putative ligand CLV3 and the receptor-like protein CLV2. We report evidence indicating that all intermediate and strong clv1 alleles are dominant negative and likely interfere with the activity of unknown receptor kinase(s) that have functional overlap with CLV1. clv1 dominant-negative alleles show major differences from dominant-negative alleles characterized to date in animal receptor kinase signaling systems, including the lack of a dominant-negative effect of kinase domain truncation and the ability of missense mutations in the extracellular domain to act in a dominant-negative manner. We analyzed chimeric receptor kinases by fusing CLV1 and BRASSINOSTEROID INSENSITIVE1 (BRI1) coding sequences and expressing these in clv1 null backgrounds. Constructs containing the CLV1 extracellular domain and the BRI1 kinase domain were strongly dominant negative in the regulation of meristem development. Furthermore, we show that CLV1 expressed within the pedicel can partially replace the function of the ERECTA receptor kinase. We propose the presence of multiple receptors that regulate meristem development in a functionally related manner whose interactions are driven by the extracellular domains and whose activation requires the kinase domain. PMID:12724544

Reappraising social emotions: the role of inferior frontal gyrus, temporo-parietal junction and insula in interpersonal emotion regulation.

PubMed

Grecucci, Alessandro; Giorgetta, Cinzia; Bonini, Nicolao; Sanfey, Alan G

2013-01-01

Previous studies have reported the effect of emotion regulation (ER) strategies on both individual and social decision-making, however, the effect of regulation on socially driven emotions independent of decisions is still unclear. In the present study, we investigated the neural effects of using reappraisal to both up- and down-regulate socially driven emotions. Participants played the Dictator Game (DG) in the role of recipient while undergoing fMRI, and concurrently applied the strategies of either up-regulation (reappraising the proposer's intentions as more negative), down-regulation (reappraising the proposer's intentions as less negative), as well as a baseline "look" condition. Results showed that regions responding to the implementation of reappraisal (effect of strategy, that is, "regulating regions") were the inferior and middle frontal gyrus, temporo parietal junction and insula bilaterally. Importantly, the middle frontal gyrus activation correlated with the frequency of regulatory strategies in daily life, with the insula activation correlating with the perceived ability to reappraise the emotions elicited by the social situation. Regions regulated by reappraisal (effect of regulation, that is, "regulated regions") were the striatum, the posterior cingulate and the insula, showing increased activation for the up-regulation and reduced activation for down-regulation, both compared to the baseline condition. When analyzing the separate effects of partners' behavior, selfish behavior produced an activation of the insula, not observed when subjects were treated altruistically. Here we show for the first time that interpersonal ER strategies can strongly affect neural responses when experiencing socially driven emotions. Clinical implications of these findings are also discussed to understand how the way we interpret others' intentions may affect the way we emotionally react.

Reappraising social emotions: the role of inferior frontal gyrus, temporo-parietal junction and insula in interpersonal emotion regulation

PubMed Central

Grecucci, Alessandro; Giorgetta, Cinzia; Bonini, Nicolao; Sanfey, Alan G.

2013-01-01

Previous studies have reported the effect of emotion regulation (ER) strategies on both individual and social decision-making, however, the effect of regulation on socially driven emotions independent of decisions is still unclear. In the present study, we investigated the neural effects of using reappraisal to both up- and down-regulate socially driven emotions. Participants played the Dictator Game (DG) in the role of recipient while undergoing fMRI, and concurrently applied the strategies of either up-regulation (reappraising the proposer's intentions as more negative), down-regulation (reappraising the proposer's intentions as less negative), as well as a baseline “look” condition. Results showed that regions responding to the implementation of reappraisal (effect of strategy, that is, “regulating regions”) were the inferior and middle frontal gyrus, temporo parietal junction and insula bilaterally. Importantly, the middle frontal gyrus activation correlated with the frequency of regulatory strategies in daily life, with the insula activation correlating with the perceived ability to reappraise the emotions elicited by the social situation. Regions regulated by reappraisal (effect of regulation, that is, “regulated regions”) were the striatum, the posterior cingulate and the insula, showing increased activation for the up-regulation and reduced activation for down-regulation, both compared to the baseline condition. When analyzing the separate effects of partners' behavior, selfish behavior produced an activation of the insula, not observed when subjects were treated altruistically. Here we show for the first time that interpersonal ER strategies can strongly affect neural responses when experiencing socially driven emotions. Clinical implications of these findings are also discussed to understand how the way we interpret others' intentions may affect the way we emotionally react. PMID:24027512

Suppressor of Cytokine Signaling 2 Negatively Regulates NK Cell Differentiation by Inhibiting JAK2 Activity

PubMed Central

Kim, Won Sam; Kim, Mi Jeong; Kim, Dong Oh; Byun, Jae-Eun; Huy, Hangsak; Song, Hae Young; Park, Young-Jun; Kim, Tae-Don; Yoon, Suk Ran; Choi, Eun-Ji; Jung, Haiyoung; Choi, Inpyo

2017-01-01

Suppressor of cytokine signaling (SOCS) proteins are negative regulators of cytokine responses. Although recent reports have shown regulatory roles for SOCS proteins in innate and adaptive immunity, their roles in natural killer (NK) cell development are largely unknown. Here, we show that SOCS2 is involved in NK cell development. SOCS2−/− mice showed a high frequency of NK cells in the bone marrow and spleen. Knockdown of SOCS2 was associated with enhanced differentiation of NK cells in vitro, and the transplantation of hematopoietic stem cells (HSCs) into congenic mice resulted in enhanced differentiation in SOCS2−/− HSCs. We found that SOCS2 could inhibit Janus kinase 2 (JAK2) activity and JAK2-STAT5 signaling pathways via direct interaction with JAK2. Furthermore, SOCS2−/− mice showed a reduction in lung metastases and an increase in survival following melanoma challenge. Overall, our findings suggest that SOCS2 negatively regulates the development of NK cells by inhibiting JAK2 activity via direct interaction. PMID:28383049

Negative regulation of neuronal cell differentiation by INHAT subunit SET/TAF-Iβ.

PubMed

Kim, Dong-Wook; Kim, Kee-Beom; Kim, Ji-Young; Lee, Kyu-Sun; Seo, Sang-Beom

2010-09-24

Epigenetic modification plays an important role in transcriptional regulation. As a subunit of the INHAT (inhibitor of histone acetyltransferases) complex, SET/TAF-Iβ evidences transcriptional repression activity. In this study, we demonstrate that SET/TAF-Iβ is abundantly expressed in neuronal tissues of Drosophila embryos. It is expressed at high levels prior to and in early stages of neuronal development, and gradually reduced as differentiation proceeds. SET/TAF-Iβ binds to the promoters of a subset of neuronal development markers and negatively regulates the transcription of these genes. The results of this study show that the knockdown of SET/TAF-Iβ by si-RNA induces neuronal cell differentiation, thus implicating SET/TAF-Iβ as a negative regulator of neuronal development. Copyright © 2010 Elsevier Inc. All rights reserved.

Ubiquitin carboxyl terminal hydrolase L1 negatively regulates TNF{alpha}-mediated vascular smooth muscle cell proliferation via suppressing ERK activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichikawa, Tomonaga; Li, Jinqing; Dong, Xiaoyu

2010-01-01

Deubiquitinating enzymes (DUBs) appear to be critical regulators of a multitude of processes such as proliferation, apoptosis, differentiation, and inflammation. We have recently demonstrated that a DUB of ubiquitin carboxyl terminal hydrolase L1 (UCH-L1) inhibits vascular lesion formation via suppressing inflammatory responses in vasculature. However, the precise underlying mechanism remains to be defined. Herein, we report that a posttranscriptional up-regulation of UCH-L1 provides a negative feedback to tumor necrosis factor alpha (TNF{alpha})-mediated activation of extracellular signal-regulated kinases (ERK) and proliferation in vascular smooth muscle cells (VSMCs). In rat adult VSMCs, adenoviral over-expression of UCH-L1 inhibited TNF{alpha}-induced activation of ERK andmore » DNA synthesis. In contrast, over-expression of UCH-L1 did not affect platelet derived growth factor (PDGF)-induced VSMC proliferation and activation of growth stimulating cascades including ERK. TNF{alpha} hardly altered UCH-L1 mRNA expression and stability; however, up-regulated UCH-L1 protein expression via increasing UCH-L1 translation. These results uncover a novel mechanism by which UCH-L1 suppresses vascular inflammation.« less

TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase.

PubMed

Wang, Wei; Huang, Xuan; Xin, Hong-Bo; Fu, Mingui; Xue, Aimin; Wu, Zhao-Hui

2015-05-22

DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Notch and PKC are involved in formation of the lateral region of the dorso-ventral axis in Drosophila embryos.

PubMed

Tremmel, Daniel M; Resad, Sedat; Little, Christopher J; Wesley, Cedric S

2013-01-01

The Notch gene encodes an evolutionarily conserved cell surface receptor that generates regulatory signals based on interactions between neighboring cells. In Drosophila embryos it is normally expressed at a low level due to strong negative regulation. When this negative regulation is abrogated neurogenesis in the ventral region is suppressed, the development of lateral epidermis is severely disrupted, and the dorsal aminoserosa is expanded. Of these phenotypes only the anti-neurogenic phenotype could be linked to excess canonical Notch signaling. The other phenotypes were linked to high levels of Notch protein expression at the surface of cells in the lateral regions indicating that a non-canonical Notch signaling activity normally functions in these regions. Results of our studies reported here provide evidence. They show that Notch activities are inextricably linked to that of Pkc98E, the homolog of mammalian PKCδ. Notch and Pkc98E up-regulate the levels of the phosphorylated form of IκBCactus, a negative regulator of Toll signaling, and Mothers against dpp (MAD), an effector of Dpp signaling. Our data suggest that in the lateral regions of the Drosophila embryos Notch activity, in conjunction with Pkc98E activity, is used to form the slopes of the opposing gradients of Toll and Dpp signaling that specify cell fates along the dorso-ventral axis.

Notch and PKC Are Involved in Formation of the Lateral Region of the Dorso-Ventral Axis in Drosophila Embryos

PubMed Central

Tremmel, Daniel M.; Resad, Sedat; Little, Christopher J.; Wesley, Cedric S.

2013-01-01

The Notch gene encodes an evolutionarily conserved cell surface receptor that generates regulatory signals based on interactions between neighboring cells. In Drosophila embryos it is normally expressed at a low level due to strong negative regulation. When this negative regulation is abrogated neurogenesis in the ventral region is suppressed, the development of lateral epidermis is severely disrupted, and the dorsal aminoserosa is expanded. Of these phenotypes only the anti-neurogenic phenotype could be linked to excess canonical Notch signaling. The other phenotypes were linked to high levels of Notch protein expression at the surface of cells in the lateral regions indicating that a non-canonical Notch signaling activity normally functions in these regions. Results of our studies reported here provide evidence. They show that Notch activities are inextricably linked to that of Pkc98E, the homolog of mammalian PKCδ. Notch and Pkc98E up-regulate the levels of the phosphorylated form of IκBCactus, a negative regulator of Toll signaling, and Mothers against dpp (MAD), an effector of Dpp signaling. Our data suggest that in the lateral regions of the Drosophila embryos Notch activity, in conjunction with Pkc98E activity, is used to form the slopes of the opposing gradients of Toll and Dpp signaling that specify cell fates along the dorso-ventral axis. PMID:23861806

Branched-Chain Amino Acid Negatively Regulates KLF15 Expression via PI3K-AKT Pathway

PubMed Central

Liu, Yunxia; Dong, Weibing; Shao, Jing; Wang, Yibin; Zhou, Meiyi; Sun, Haipeng

2017-01-01

Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively controlled by BCAA.Interestingly, BCAA starvation induced PI3K-AKT signaling. KLF15 induction by BCAA starvation was blocked by PI3K and AKT inhibitors, indicating the activation of PI3K-AKT signaling pathway mediated the KLF15 induction. BCAA regulated KLF15 expression at transcriptional level but not post-transcriptional level. However, BCAA starvation failed to increase the KLF15-promoter-driven luciferase expression, suggesting KLF15 promoter activity was not directly controlled by BCAA. Finally, fasting reduced BCAA abundance in mice and KLF15 expression was dramatically induced in muscle and white adipose tissue, but not in liver. Together, these data demonstrated BCAA negatively regulated KLF15 expression, suggesting a novel molecular mechanism underlying BCAA's multiple functions in metabolic regulation. PMID:29118722

Branched-Chain Amino Acid Negatively Regulates KLF15 Expression via PI3K-AKT Pathway.

PubMed

Liu, Yunxia; Dong, Weibing; Shao, Jing; Wang, Yibin; Zhou, Meiyi; Sun, Haipeng

2017-01-01

Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively controlled by BCAA.Interestingly, BCAA starvation induced PI3K-AKT signaling. KLF15 induction by BCAA starvation was blocked by PI3K and AKT inhibitors, indicating the activation of PI3K-AKT signaling pathway mediated the KLF15 induction. BCAA regulated KLF15 expression at transcriptional level but not post-transcriptional level. However, BCAA starvation failed to increase the KLF15-promoter-driven luciferase expression, suggesting KLF15 promoter activity was not directly controlled by BCAA. Finally, fasting reduced BCAA abundance in mice and KLF15 expression was dramatically induced in muscle and white adipose tissue, but not in liver. Together, these data demonstrated BCAA negatively regulated KLF15 expression, suggesting a novel molecular mechanism underlying BCAA's multiple functions in metabolic regulation.

Negative feedback regulation of TGF-beta signaling by the SnoN oncoprotein.

PubMed

Stroschein, S L; Wang, W; Zhou, S; Zhou, Q; Luo, K

1999-10-22

Smad proteins mediate transforming growth factor-beta (TGF-beta) signaling to regulate cell growth and differentiation. The SnoN oncoprotein was found to interact with Smad2 and Smad4 and to repress their abilities to activate transcription through recruitment of the transcriptional corepressor N-CoR. Immediately after TGF-beta stimulation, SnoN is rapidly degraded by the nuclear accumulation of Smad3, allowing the activation of TGF-beta target genes. By 2 hours, TGF-beta induces a marked increase in SnoN expression, resulting in termination of Smad-mediated transactivation. Thus, SnoN maintains the repressed state of TGF-beta-responsive genes in the absence of ligand and participates in negative feedback regulation of TGF-beta signaling.

Small-molecule studies identify CDK8 as a regulator of IL-10 in myeloid cells.

PubMed

Johannessen, Liv; Sundberg, Thomas B; O'Connell, Daniel J; Kolde, Raivo; Berstler, James; Billings, Katelyn J; Khor, Bernard; Seashore-Ludlow, Brinton; Fassl, Anne; Russell, Caitlin N; Latorre, Isabel J; Jiang, Baishan; Graham, Daniel B; Perez, Jose R; Sicinski, Piotr; Phillips, Andrew J; Schreiber, Stuart L; Gray, Nathanael S; Shamji, Alykhan F; Xavier, Ramnik J

2017-10-01

Enhancing production of the anti-inflammatory cytokine interleukin-10 (IL-10) is a promising strategy to suppress pathogenic inflammation. To identify new mechanisms regulating IL-10 production, we conducted a phenotypic screen for small molecules that enhance IL-10 secretion from activated dendritic cells. Mechanism-of-action studies using a prioritized hit from the screen, BRD6989, identified the Mediator-associated kinase CDK8, and its paralog CDK19, as negative regulators of IL-10 production during innate immune activation. The ability of BRD6989 to upregulate IL-10 is recapitulated by multiple, structurally differentiated CDK8 and CDK19 inhibitors and requires an intact cyclin C-CDK8 complex. Using a highly parallel pathway reporter assay, we identified a role for enhanced AP-1 activity in IL-10 potentiation following CDK8 and CDK19 inhibition, an effect associated with reduced phosphorylation of a negative regulatory site on c-Jun. These findings identify a function for CDK8 and CDK19 in regulating innate immune activation and suggest that these kinases may warrant consideration as therapeutic targets for inflammatory disorders.

The mammalian target of rapamycin signaling pathway regulates myocyte enhancer factor-2C phosphorylation levels through integrin-linked kinase in goat skeletal muscle satellite cells.

PubMed

Wu, Haiqing; Ren, Yu; Pan, Wei; Dong, Zhenguo; Cang, Ming; Liu, Dongjun

2015-11-01

Mammalian target of rapamycin (mTOR) signaling pathway plays a key role in muscle development and is involved in multiple intracellular signaling pathways. Myocyte enhancer factor-2 (MEF2) regulates muscle cell proliferation and differentiation. However, how the mTOR signaling pathway regulates MEF2 activity remains unclear. We isolated goat skeletal muscle satellite cells (gSSCs) as model cells to explore mTOR signaling pathway regulation of MEF2C. We inhibited mTOR activity in gSSCs with PP242 and found that MEF2C phosphorylation was decreased and that muscle creatine kinase (MCK) expression was suppressed. Subsequently, we detected integrin-linked kinase (ILK) using MEF2C coimmunoprecipitation; ILK and MEF2C were colocalized in the gSSCs. We found that inhibiting mTOR activity increased ILK phosphorylation levels and that inhibiting ILK activity with Cpd 22 and knocking down ILK with small interfering RNA increased MEF2C phosphorylation and MCK expression. In the presence of Cpd 22, mTOR activity inhibition did not affect MEF2C phosphorylation. Moreover, ILK dephosphorylated MEF2C in vitro. These results suggest that the mTOR signaling pathway regulates MEF2C positively and regulates ILK negatively and that ILK regulates MEF2C negatively. It appears that the mTOR signaling pathway regulates MEF2C through ILK, further regulating the expression of muscle-related genes in gSSCs. © 2015 International Federation for Cell Biology.

Endothelial cell SHP-2 negatively regulates neutrophil adhesion and promotes transmigration by enhancing ICAM-1-VE-cadherin interaction.

PubMed

Yan, Meiping; Zhang, Xinhua; Chen, Ao; Gu, Wei; Liu, Jie; Ren, Xiaojiao; Zhang, Jianping; Wu, Xiaoxiong; Place, Aaron T; Minshall, Richard D; Liu, Guoquan

2017-11-01

Intercellular adhesion molecule-1 (ICAM-1) mediates the firm adhesion of leukocytes to endothelial cells and initiates subsequent signaling that promotes their transendothelial migration (TEM). Vascular endothelial (VE)-cadherin plays a critical role in endothelial cell-cell adhesion, thereby controlling endothelial permeability and leukocyte transmigration. This study aimed to determine the molecular signaling events that originate from the ICAM-1-mediated firm adhesion of neutrophils that regulate VE-cadherin's role as a negative regulator of leukocyte transmigration. We observed that ICAM-1 interacts with Src homology domain 2-containing phosphatase-2 (SHP-2), and SHP-2 down-regulation via silencing of small interfering RNA in endothelial cells enhanced neutrophil adhesion to endothelial cells but inhibited neutrophil transmigration. We also found that VE-cadherin associated with the ICAM-1-SHP-2 complex. Moreover, whereas the activation of ICAM-1 leads to VE-cadherin dissociation from ICAM-1 and VE-cadherin association with actin, SHP-2 down-regulation prevented ICAM-1-VE-cadherin association and promoted VE-cadherin-actin association. Furthermore, SHP-2 down-regulation in vivo promoted LPS-induced neutrophil recruitment in mouse lung but delayed neutrophil extravasation. These results suggest that SHP-2- via association with ICAM-1-mediates ICAM-1-induced Src activation and modulates VE-cadherin switching association with ICAM-1 or actin, thereby negatively regulating neutrophil adhesion to endothelial cells and enhancing their TEM.-Yan, M., Zhang, X., Chen, A., Gu, W., Liu, J., Ren, X., Zhang, J., Wu, X., Place, A. T., Minshall, R. D., Liu, G. Endothelial cell SHP-2 negatively regulates neutrophil adhesion and promotes transmigration by enhancing ICAM-1-VE-cadherin interaction. © FASEB.

Self-regulation via neural simulation

PubMed Central

Gilead, Michael; Boccagno, Chelsea; Silverman, Melanie; Hassin, Ran R.; Weber, Jochen; Ochsner, Kevin N.

2016-01-01

Can taking the perspective of other people modify our own affective responses to stimuli? To address this question, we examined the neurobiological mechanisms supporting the ability to take another person’s perspective and thereby emotionally experience the world as they would. We measured participants’ neural activity as they attempted to predict the emotional responses of two individuals that differed in terms of their proneness to experience negative affect. Results showed that behavioral and neural signatures of negative affect (amygdala activity and a distributed multivoxel pattern reflecting affective negativity) simulated the presumed affective state of the target person. Furthermore, the anterior medial prefrontal cortex (mPFC)—a region implicated in mental state inference—exhibited a perspective-dependent pattern of connectivity with the amygdala, and the multivoxel pattern of activity within the mPFC differentiated between the two targets. We discuss the implications of these findings for research on perspective-taking and self-regulation. PMID:27551094

miR-133 is a key negative regulator of CDC42-PAK pathway in gastric cancer.

PubMed

Cheng, Zhenguo; Liu, Funan; Wang, Guanqiao; Li, Yanshu; Zhang, Hongyan; Li, Feng

2014-12-01

Cell division cycle 42 (CDC42), an important member of the Ras homolog (Rho) family, plays a key role in regulating multiple cellular processes such as cell cycle progression, migration, cell cytoskeleton organization, cell fate determination and differentiation. Among the downstream effectors of CDC42, P21-activated kinases (PAKs) obtain the most attention. Although a large body of evidence indicates that CDC42/PAKs pathway plays important role in tumor growth, invasion and metastasis, the mechanism of their negative regulation remains unclear. Here, we identified CDC42, a PAKs activating factor, was a target of miR-133. Ectopic overexpression of miRNAs not only downregulated CDC42 expression and PAKs activation, but also inhibited cancer cell proliferation and migration. We also found that miR-133 was down-regulated in 180 pairs gastric cancer tissues. miR-133 expression was negatively associated with tumor size, invasion depth and peripheral organ metastasis. Besides, dysfunction of miR-133 was an independent prognosis factor for overall survival. Our findings could provide new insights into the molecular mechanisms of gastric carcinogenesis, and may help facilitating development of CDC42/PAK-based therapies for human cancer. Copyright © 2014 Elsevier Inc. All rights reserved.

Negative regulation of BMP signaling by the ski oncoprotein.

PubMed

Luo, Kunxin

2003-01-01

The bone morphogenetic proteins (BMPs) play important roles in the regulation of multiple aspects of vertebrate development. BMPs signal through the cell surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5, and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. The activity of this signal pathway can be modulated both by extracellular factors that regulate the binding of BMPs to the receptor and by intracellular proteins that interact with the Smad proteins. We have shown that Ski is an important negative regulator of the Smad proteins. Ski can bind to the BMP-Smad protein complexes in response to BMP and repress their ability to activate BMP target genes through disruption of a functional Smad complex and through recruitment of transcriptional co-repressors. The antagonism of BMP signaling by Ski results in neural specification in Xenopus embryos and inhibition of osteoblast differentiation in mouse bone-marrow stromal progenitor cells. This ability to modulate BMP signaling by Ski may play an important role in the regulation of craniofacial, neuronal, and skeletal muscle development.

Inhibition of the Jun N-Terminal Protein Kinase Pathway by SHIP-1, a Lipid Phosphatase That Interacts with the Adaptor Molecule Dok-3

PubMed Central

Robson, Jeffrey D.; Davidson, Dominique; Veillette, André

2004-01-01

Dok-3 is a Dok-related adaptor expressed in B cells and macrophages. Previously, we reported that Dok-3 is an inhibitor of B-cell activation in A20 B cells and that it associates with SHIP-1, a 5′ inositol-specific lipid phosphatase, as well as Csk, a negative regulator of Src kinases. Here, we demonstrate that Dok-3 suppresses B-cell activation by way of its interaction with SHIP-1, rather than Csk. Our biochemical analyses showed that the Dok-3-SHIP-1 complex acts by selectively inhibiting the B-cell receptor (BCR)-evoked activation of the Jun N-terminal protein kinase (JNK) cascade without affecting overall protein tyrosine phosphorylation or activation of previously described SHIP-1 targets like Btk and Akt/PKB. Studies of B cells derived from SHIP-1-deficient mice showed that BCR-triggered activation of JNK is enhanced in the absence of SHIP-1, implying that the Dok-3-SHIP-1 complex (or a related mechanism) is a physiological negative regulator of the JNK cascade in normal B cells. Together, these data elucidate the mechanism by which Dok-3 inhibits B-cell activation. Furthermore, they provide evidence that SHIP-1 can be a negative regulator of JNK signaling in B cells. PMID:14993273

The Rice Transcription Factor WRKY53 Suppresses Herbivore-Induced Defenses by Acting as a Negative Feedback Modulator of Mitogen-Activated Protein Kinase Activity1

PubMed Central

Hu, Lingfei; Ye, Meng; Zhang, Tongfang; Zhou, Guoxin; Wang, Qi; Lu, Jing

2015-01-01

The mechanisms by which herbivore-attacked plants activate their defenses are well studied. By contrast, little is known about the regulatory mechanisms that allow them to control their defensive investment and avoid a defensive overshoot. We characterized a rice (Oryza sativa) WRKY gene, OsWRKY53, whose expression is rapidly induced upon wounding and induced in a delayed fashion upon attack by the striped stem borer (SSB) Chilo suppressalis. The transcript levels of OsWRKY53 are independent of endogenous jasmonic acid but positively regulated by the mitogen-activated protein kinases OsMPK3/OsMPK6. OsWRKY53 physically interacts with OsMPK3/OsMPK6 and suppresses their activity in vitro. By consequence, it modulates the expression of defensive, MPK-regulated WRKYs and thereby reduces jasmonic acid, jasmonoyl-isoleucine, and ethylene induction. This phytohormonal reconfiguration is associated with a reduction in trypsin protease inhibitor activity and improved SSB performance. OsWRKY53 is also shown to be a negative regulator of plant growth. Taken together, these results show that OsWRKY53 functions as a negative feedback modulator of MPK3/MPK6 and thereby acts as an early suppressor of induced defenses. OsWRKY53 therefore enables rice plants to control the magnitude of their defensive investment during early signaling. PMID:26453434

Emotion regulation deficits in regular marijuana users.

PubMed

Zimmermann, Kaeli; Walz, Christina; Derckx, Raissa T; Kendrick, Keith M; Weber, Bernd; Dore, Bruce; Ochsner, Kevin N; Hurlemann, René; Becker, Benjamin

2017-08-01

Effective regulation of negative affective states has been associated with mental health. Impaired regulation of negative affect represents a risk factor for dysfunctional coping mechanisms such as drug use and thus could contribute to the initiation and development of problematic substance use. This study investigated behavioral and neural indices of emotion regulation in regular marijuana users (n = 23) and demographically matched nonusing controls (n = 20) by means of an fMRI cognitive emotion regulation (reappraisal) paradigm. Relative to nonusing controls, marijuana users demonstrated increased neural activity in a bilateral frontal network comprising precentral, middle cingulate, and supplementary motor regions during reappraisal of negative affect (P < 0.05, FWE) and impaired emotion regulation success on the behavioral level (P < 0.05). Amygdala-focused analyses further revealed impaired amygdala downregulation in the context of decreased amygdala-dorsolateral prefrontal cortex functional connectivity (P < 0.05, FWE) during reappraisal in marijuana users relative to controls. Together, the present findings could reflect an unsuccessful attempt of compensatory recruitment of additional neural resources in the context of disrupted amygdala-prefrontal interaction during volitional emotion regulation in marijuana users. As such, impaired volitional regulation of negative affect might represent a consequence of, or risk factor for, regular marijuana use. Hum Brain Mapp 38:4270-4279, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Negative regulators in homeostasis of naïve peripheral T cells.

PubMed

Modiano, Jaime F; Johnson, Lisa D S; Bellgrau, Donald

2008-01-01

It is now apparent that naïve peripheral T cells are a dynamic population where active processes prevent inappropriate activation while supporting survival. The process of thymic education makes naïve peripheral T cells dependent on interactions with self-MHC for survival. However, as these signals can potentially result in inappropriate activation, various non-redundant, intrinsic negative regulatory molecules including Tob, Nfatc2, and Smad3 actively enforce T cell quiescence. Interactions among these pathways are only now coming to light and may include positive or negative crosstalk. In the case of positive crosstalk, self-MHC initiated signals and intrinsic negative regulatory factors may cooperate to dampen T cell activation and sustain peripheral tolerance in a binary fashion (on-off). In the case of negative crosstalk, self-MHC signals may promote survival through partial activation while intrinsic negative regulatory factors act as rheostats to restrain cell cycle entry and prevent T cells from crossing a threshold that would break tolerance.

Free Market Ideology and Deregulation in Colorado's Oilfields: Evidence for triple movement activism?

PubMed

Malin, Stephanie A; Mayer, Adam; Shreeve, Kelly; Olson-Hazboun, Shawn K; Adgate, John

2017-01-01

Unconventional oil and gas extraction (UOGE) has spurred an unprecedented boom in on-shore production in the U.S. Despite a surge in related research, a void exists regarding inquiries into policy outcomes and perceptions. To address this, support for federal regulatory exemptions for UOGE is examined using survey data collected in 2015 from two northern Colorado communities. Current regulatory exemptions for UOGE can be understood as components of broader societal processes of neoliberalization. Free market ideology increases public support for federal regulatory exemptions for UOGE. Perceived negative impacts do not necessarily drive people to support increased federal regulation. Utilizing neo-Polanyian theory, interaction between free market ideology and perceived negative impacts is explored. Free market ideology appears to moderate people's views of regulation: increasing the effect of perceived negative impacts while simultaneously increasing support for de regulation. To conclude, the ways in which free market ideology might normalize the impacts of UOGE activity are discussed.

Reappraising the ultimatum: an fMRI study of emotion regulation and decision making.

PubMed

Grecucci, Alessandro; Giorgetta, Cinzia; Van't Wout, Mascha; Bonini, Nicolao; Sanfey, Alan G

2013-02-01

Emotion regulation strategies provide a means by which to modulate our social behavior. In this study, we investigated the effect of using reappraisal to both up- and downregulate social decision making. After being instructed on how to use reappraisal, participants played the Ultimatum Game while undergoing functional magnetic resonance imaging and applied the strategies of upregulation (reappraising the proposer's intentions as more negative), down-regulation (reappraising the proposer's intentions as less negative), as well as a baseline "look" condition. As hypothesized, when reappraising, decision acceptance rates were altered, with a greater number of unfair offers accepted while down-regulating and a greater number of unfair offers rejected while upregulating, both relative to the baseline condition. At the neural level, during reappraisal, significant activations were observed in the inferior and middle frontal gyrus (MFG), in addition to the medial prefrontal cortex and cingulate gyrus for unfair offers only. Regulated decisions involved left inferior frontal gyrus for upregulation and MFG for down-regulation strategies, respectively. Importantly, the effects of emotion modulation were evident in posterior insula, with less activation for down-regulation and more activation for upregulation in these areas. Notably, we show for the first time that top-down strategies such as reappraisal strongly affect our socioeconomic decisions.

mTOR referees memory and disease through mRNA repression and competition.

PubMed

Raab-Graham, Kimberly F; Niere, Farr

2017-06-01

Mammalian target of rapamycin (mTOR) activity is required for memory and is dysregulated in disease. Activation of mTOR promotes protein synthesis; however, new studies are demonstrating that mTOR activity also represses the translation of mRNAs. Almost three decades ago, Kandel and colleagues hypothesised that memory was due to the induction of positive regulators and removal of negative constraints. Are these negative constraints repressed mRNAs that code for proteins that block memory formation? Herein, we will discuss the mRNAs coded by putative memory suppressors, how activation/inactivation of mTOR repress protein expression at the synapse, how mTOR activity regulates RNA binding proteins, mRNA stability, and translation, and what the possible implications of mRNA repression are to memory and neurodegenerative disorders. © 2017 Federation of European Biochemical Societies.

Transforming growth factor β-activated kinase 1 negatively regulates interleukin-1α-induced stromal-derived factor-1 expression in vascular smooth muscle cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Bin; Li, Wei; Zheng, Qichang

Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1α (IL-1α) was investigated in primary rat VSMCs. We found IL-1α promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein β (C/EBPβ) in an IκB kinase β (IKKβ) signaling-dependent manner. Moreover, IL-1α-induced expression of C/EBPβ and SDF-1 was significantly potentiated by knockdown of transforming growth factor β-activated kinase 1 (TAK1), an upstream activator of IKKβ signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negativemore » effect on IL-1α-induced expression of C/EBPβ and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1α-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling. - Highlights: • IL-1α induces IKKβ signaling-dependent SDF-1 expression by up-regulating C/EBPβ. • Activation of TAK1 by IL-1α negatively regulates C/EBPβ-dependent SDF-1 expression. • IL-1α-induced TAK1/p38 MAPK signaling counteracts ROS-dependent SDF-1 expression. • TAK1 counteracts IL-1α-induced SDF-1 expression by attenuating NRF2 up-regulation.« less

Affect and Subsequent Physical Activity: An Ambulatory Assessment Study Examining the Affect-Activity Association in a Real-Life Context.

PubMed

Niermann, Christina Y N; Herrmann, Christian; von Haaren, Birte; van Kann, Dave; Woll, Alexander

2016-01-01

Traditionally, cognitive, motivational, and volitional determinants have been used to explain and predict health behaviors such as physical activity. Recently, the role of affect in influencing and regulating health behaviors received more attention. Affects as internal cues may automatically activate unconscious processes of behavior regulation. The aim of our study was to examine the association between affect and physical activity in daily life. In addition, we studied the influence of the habit of being physically active on this relationship. An ambulatory assessment study in 89 persons (33.7% male, 25 to 65 years, M = 45.2, SD = 8.1) was conducted. Affect was assessed in the afternoon on 5 weekdays using smartphones. Physical activity was measured continuously objectively using accelerometers and subjectively using smartphones in the evening. Habit strength was assessed at the beginning of the diary period. The outcomes were objectively and subjectively measured moderate-to-vigorous physical activity (MVPA) performed after work. Multilevel regression models were used to analyze the association between affect and after work MVPA. In addition, the cross-level interaction of habit strength and affect on after work MVPA was tested. Positive affect was positively related to objectively measured and self-reported after work MVPA: the greater the positive affect the more time persons subsequently spent on MVPA. An inverse relationship was found for negative affect: the greater the negative affect the less time persons spent on MVPA. The cross-level interaction effect was significant only for objectively measured MVPA. A strong habit seems to strengthen both the positive influence of positive affect and the negative influence of negative affect. The results of this study confirm previous results and indicate that affect plays an important role for the regulation of physical activity behavior in daily life. The results for positive affect were consistent. However, in contrast to previous reports of no or an inverse association, negative affect decreased subsequent MVPA. These inconsistencies may be-in part-explained by the different measurements of affect in our and other studies. Therefore, further research is warranted to gain more insight into the association between affect and physical activity.

PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shahaf, Galit; Rotem-Dai, Noa; Koifman, Gabriela

2012-04-15

The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKC{eta} isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKC{eta}-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKC{eta}-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKTmore » Ser473. While PKC{eta} exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKC{eta} and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKC{eta} expression, suggesting that PKC{eta} acts through a different route to increase cell survival. Hence, our studies show that PKC{eta} provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.« less

BRAFV600E Negatively Regulates the AKT Pathway in Melanoma Cell Lines

PubMed Central

Chen, Brenden; Tardell, Christine; Higgins, Brian; Packman, Kathryn; Boylan, John F.; Niu, Huifeng

2012-01-01

Cross-feedback activation of MAPK and AKT pathways is implicated as a resistance mechanism for cancer therapeutic agents targeting either RAF/MEK or PI3K/AKT/mTOR. It is thus important to have a better understanding of the molecular resistance mechanisms to improve patient survival benefit from these agents. Here we show that BRAFV600E is a negative regulator of the AKT pathway. Expression of BRAFV600E in NIH3T3 cells significantly suppresses MEK inhibitor (RG7167) or mTORC1 inhibitor (rapamycin) induced AKT phosphorylation (pAKT) and downstream signal activation. Treatment-induced pAKT elevation is found in BRAF wild type melanoma cells but not in a subset of melanoma cell lines harboring BRAFV600E. Knock-down of BRAFV600E in these melanoma cells elevates basal pAKT and downstream signals, whereas knock-down of CRAF, MEK1/2 or ERK1/2 or treatment with a BRAF inhibitor have no impact on pAKT. Mechanistically, we show that BRAFV600E interacts with rictor complex (mTORC2) and regulates pAKT through mTORC2. BRAFV600E is identified in mTORC2 after immunoprecipitation of rictor. Knock-down of rictor abrogates BRAFV600E depletion induced pAKT. Knock-down of BRAFV600E enhances cellular enzyme activity of mTORC2. Aberrant activation of AKT pathway by PTEN loss appears to override the negative impact of BRAFV600E on pAKT. Taken together, our findings suggest that in a subset of BRAFV600E melanoma cells, BRAFV600E negatively regulates AKT pathway in a rictor-dependent, MEK/ERK and BRAF kinase-independent manner. Our study reveals a novel molecular mechanism underlying the regulation of feedback loops between the MAPK and AKT pathways. PMID:22880048

LKB1 tumor suppressor and salt-inducible kinases negatively regulate human T-cell leukemia virus type 1 transcription

PubMed Central

2013-01-01

Background Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL). Treatment options are limited and prophylactic agents are not available. We have previously demonstrated an essential role for CREB-regulating transcriptional coactivators (CRTCs) in HTLV-1 transcription. Results In this study we report on the negative regulatory role of LKB1 tumor suppressor and salt-inducible kinases (SIKs) in the activation of HTLV-1 long terminal repeats (LTR) by the oncoprotein Tax. Activation of LKB1 and SIKs effectively blunted Tax activity in a phosphorylation-dependent manner, whereas compromising these kinases, but not AMP-dependent protein kinases, augmented Tax function. Activated LKB1 and SIKs associated with Tax and suppressed Tax-induced LTR activation by counteracting CRTCs and CREB. Enforced expression of LKB1 or SIK1 in cells transfected with HTLV-1 molecular clone pX1MT repressed proviral transcription. On the contrary, depletion of LKB1 in pX1MT-transfected cells and in HTLV-1-transformed T cells boosted the expression of Tax. Treatment of HTLV-1 transformed cells with metformin led to LKB1/SIK1 activation, reduction in Tax expression, and inhibition of cell proliferation. Conclusions Our findings revealed a new function of LKB1 and SIKs as negative regulators of HTLV-1 transcription. Pharmaceutical activation of LKB1 and SIKs might be considered as a new strategy in anti-HTLV-1 and anti-ATL therapy. PMID:23577667

Identification of a negative regulator of gibberellin action, HvSPY, in barley.

PubMed Central

Robertson, M; Swain, S M; Chandler, P M; Olszewski, N E

1998-01-01

To broaden our understanding of the molecular mechanisms of gibberellin (GA) action, we isolated a spindly clone (HvSPY) from barley cultivar Himalaya and tested whether the HvSPY protein would modulate GA action in barley aleurone. The HvSPY cDNA showed high sequence identity to Arabidopsis SPY along its entire length, and the barley protein functionally complemented the spy-3 mutation. HvSPY and SPY proteins showed sequence relatedness with animal O-linked N-acetylglucosamine transferases (OGTs), suggesting that they may also have OGT activity. HvSPY has a locus distinct from that of Sln, a mutation that causes the constitutive GA responses of slender barley, which phenotypically resembles Arabidopsis spy mutants. The possibility that the HvSPY gene encodes a negative regulator of GA action was tested by expressing HvSPY in a barley aleurone transient assay system. HvSPY coexpression largely abolished GA3-induced activity of an alpha-amylase promoter. Surprisingly, HvSPY coexpression increased reporter gene activity from an abscisic acid (ABA)-inducible gene promoter (dehydrin), even in the absence of exogenous ABA. These results show that HvSPY modulates the transcriptional activities of two hormonally regulated promoters: negatively for a GA-induced promoter and positively for an ABA-induced promoter. PMID:9634587

Cocaine users with comorbid Cluster B personality disorders show dysfunctional brain activation and connectivity in the emotional regulation networks during negative emotion maintenance and reappraisal.

PubMed

Albein-Urios, Natalia; Verdejo-Román, Juan; Soriano-Mas, Carles; Asensio, Samuel; Martínez-González, José Miguel; Verdejo-García, Antonio

2013-12-01

Cocaine dependence often co-occurs with Cluster B personality disorders. Since both disorders are characterized by emotion regulation deficits, we predicted that cocaine comorbid patients would exhibit dysfunctional patterns of brain activation and connectivity during reappraisal of negative emotions. We recruited 18 cocaine users with comorbid Cluster B personality disorders, 17 cocaine users without comorbidities and 21 controls to be scanned using functional magnetic resonance imaging (fMRI) during performance on a reappraisal task in which they had to maintain or suppress the emotions induced by negative affective stimuli. We followed region of interest (ROI) and whole-brain approaches to investigate brain activations and connectivity associated with negative emotion experience and reappraisal. Results showed that cocaine users with comorbid personality disorders had reduced activation of the subgenual anterior cingulate cortex during negative emotion maintenance and increased activation of the lateral orbitofrontal cortex and the amygdala during reappraisal. Amygdala activation correlated with impulsivity and antisocial beliefs in the comorbid group. Connectivity analyses showed that in the cocaine comorbid group the subgenual cingulate was less efficiently connected with the amygdala and the fusiform gyri and more efficiently connected with the anterior insula during maintenance, whereas during reappraisal the left orbitofrontal cortex was more efficiently connected with the amygdala and the right orbitofrontal cortex was less efficiently connected with the dorsal striatum. We conclude that cocaine users with comorbid Cluster B personality disorders have distinctive patterns of brain activation and connectivity during maintenance and reappraisal of negative emotions, which correlate with impulsivity and dysfunctional beliefs. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

Distinct functional outputs of PTEN signalling are controlled by dynamic association with β-arrestins

PubMed Central

Lima-Fernandes, Evelyne; Enslen, Hervé; Camand, Emeline; Kotelevets, Larissa; Boularan, Cédric; Achour, Lamia; Benmerah, Alexandre; Gibson, Lucien C D; Baillie, George S; Pitcher, Julie A; Chastre, Eric; Etienne-Manneville, Sandrine; Marullo, Stefano; Scott, Mark G H

2011-01-01

The tumour suppressor PTEN (phosphatase and tensin deleted on chromosome 10) regulates major cellular functions via lipid phosphatase-dependent and -independent mechanisms. Despite its fundamental pathophysiological importance, how PTEN's cellular activity is regulated has only been partially elucidated. We report that the scaffolding proteins β-arrestins (β-arrs) are important regulators of PTEN. Downstream of receptor-activated RhoA/ROCK signalling, β-arrs activate the lipid phosphatase activity of PTEN to negatively regulate Akt and cell proliferation. In contrast, following wound-induced RhoA activation, β-arrs inhibit the lipid phosphatase-independent anti-migratory effects of PTEN. β-arrs can thus differentially control distinct functional outputs of PTEN important for cell proliferation and migration. PMID:21642958

Protein Kinase A Regulates Constitutive Expression of Small Heat-Shock Genes in an Msn2/4p-Independent and Hsf1p-Dependent Manner in Saccharomyces cerevisiae

PubMed Central

Ferguson, Scott B.; Anderson, Erik S.; Harshaw, Robyn B.; Thate, Tim; Craig, Nancy L.; Nelson, Hillary C. M.

2005-01-01

Hsf1p, the heat-shock transcription factor from Saccharomyces cerevisiae, has a low level of constitutive transcriptional activity and is kept in this state through negative regulation. In an effort to understand this negative regulation, we developed a novel genetic selection that detects altered expression from the HSP26 promoter. Using this reporter strain, we identified mutations and dosage compensators in the Ras/cAMP signaling pathway that decrease cAMP levels and increase expression from the HSP26 promoter. In yeast, low cAMP levels reduce the catalytic activity of the cAMP-dependent kinase PKA. Previous studies had proposed that the stress response transcription factors Msn2p/4p, but not Hsf1p, are repressed by PKA. However, we found that reduction or elimination of PKA activity strongly derepresses transcription of the small heat-shock genes HSP26 and HSP12, even in the absence of MSN2/4. In a strain deleted for MSN2/4 and the PKA catalytic subunits, expression of HSP12 and HSP26 depends on HSF1 expression. Our findings indicate that Hsf1p functions downstream of PKA and suggest that PKA might be involved in negative regulation of Hsf1p activity. These results represent a major change in our understanding of how PKA signaling influences the heat-shock response and heat-shock protein expression. PMID:15545649

Early growth response-1 negative feedback regulates skeletal muscle postprandial insulin sensitivity via activating Ptp1b transcription.

PubMed

Wu, Jing; Tao, Wei-Wei; Chong, Dan-Yang; Lai, Shan-Shan; Wang, Chuang; Liu, Qi; Zhang, Tong-Yu; Xue, Bin; Li, Chao-Jun

2018-03-15

Postprandial insulin desensitization plays a critical role in maintaining whole-body glucose homeostasis by avoiding the excessive absorption of blood glucose; however, the detailed mechanisms that underlie how the major player, skeletal muscle, desensitizes insulin action remain to be elucidated. Herein, we report that early growth response gene-1 ( Egr-1) is activated by insulin in skeletal muscle and provides feedback inhibition that regulates insulin sensitivity after a meal. The inhibition of the transcriptional activity of Egr-1 enhanced the phosphorylation of the insulin receptor (InsR) and Akt, thus increasing glucose uptake in L6 myotubes after insulin stimulation, whereas overexpression of Egr-1 decreased insulin sensitivity. Furthermore, deletion of Egr-1 in the skeletal muscle improved systemic insulin sensitivity and glucose tolerance, which resulted in lower blood glucose levels after refeeding. Mechanistic analysis demonstrated that EGR-1 inhibited InsR phosphorylation and glucose uptake in skeletal muscle by binding to the proximal promoter region of protein tyrosine phosphatase-1B (PTP1B) and directly activating transcription. PTP1B knockdown largely restored insulin sensitivity and enhanced glucose uptake, even under conditions of EGR-1 overexpression. Our results indicate that EGR-1/PTP1B signaling negatively regulates postprandial insulin sensitivity and suggest a potential therapeutic target for the prevention and treatment of excessive glucose absorption.-Wu, J., Tao, W.-W., Chong, D.-Y., Lai, S.-S., Wang, C., Liu, Q., Zhang, T.-Y., Xue, B., Li, C.-J. Early growth response-1 negative feedback regulates skeletal muscle postprandial insulin sensitivity via activating Ptp1b transcription.

Orphan Nuclear Receptor ERRα Controls Macrophage Metabolic Signaling and A20 Expression to Negatively Regulate TLR-Induced Inflammation.

PubMed

Yuk, Jae-Min; Kim, Tae Sung; Kim, Soo Yeon; Lee, Hye-Mi; Han, Jeongsu; Dufour, Catherine Rosa; Kim, Jin Kyung; Jin, Hyo Sun; Yang, Chul-Su; Park, Ki-Sun; Lee, Chul-Ho; Kim, Jin-Man; Kweon, Gi Ryang; Choi, Hueng-Sik; Vanacker, Jean-Marc; Moore, David D; Giguère, Vincent; Jo, Eun-Kyeong

2015-07-21

The orphan nuclear receptor estrogen-related receptor α (ERRα; NR3B1) is a key metabolic regulator, but its function in regulating inflammation remains largely unknown. Here, we demonstrate that ERRα negatively regulates Toll-like receptor (TLR)-induced inflammation by promoting Tnfaip3 transcription and fine-tuning of metabolic reprogramming in macrophages. ERRα-deficient (Esrra(-/-)) mice showed increased susceptibility to endotoxin-induced septic shock, leading to more severe pro-inflammatory responses than control mice. ERRα regulated macrophage inflammatory responses by directly binding the promoter region of Tnfaip3, a deubiquitinating enzyme in TLR signaling. In addition, Esrra(-/-) macrophages showed an increased glycolysis, but impaired mitochondrial respiratory function and biogenesis. Further, ERRα was required for the regulation of NF-κB signaling by controlling p65 acetylation via maintenance of NAD(+) levels and sirtuin 1 activation. These findings unravel a previously unappreciated role for ERRα as a negative regulator of TLR-induced inflammatory responses through inducing Tnfaip3 transcription and controlling the metabolic reprogramming. Copyright © 2015 Elsevier Inc. All rights reserved.

No fear, no panic: probing negation as a means for emotion regulation

PubMed Central

Deutsch, Roland; Platte, Petra; Pauli, Paul

2013-01-01

This electroencephalographic study investigated if negating one’s emotion results in paradoxical effects or leads to effective emotional downregulation. Healthy participants were asked to downregulate their emotions to happy and fearful faces by using negated emotional cue words (e.g. no fun, no fear). Cue words were congruent with the emotion depicted in the face and presented prior to each face. Stimuli were presented in blocks of happy and fearful faces. Blocks of passive stimulus viewing served as control condition. Active regulation reduced amplitudes of early event-related brain potentials (early posterior negativity, but not N170) and the late positive potential for fearful faces. A fronto-central negativity peaking at about 250 ms after target face onset showed larger amplitude modulations during downregulation of fearful and happy faces. Behaviorally, negating was more associated with reappraisal than with suppression. Our results suggest that in an emotional context, negation processing could be quite effective for emotional downregulation but that its effects depend on the type of the negated emotion (pleasant vs unpleasant). Results are discussed in the context of dual process models of cognition and emotion regulation. PMID:22490924

Back to basics: a naturalistic assessment of the experience and regulation of emotion.

PubMed

Heiy, Jane E; Cheavens, Jennifer S

2014-10-01

Emotion regulation research links regulatory responding to important outcomes in psychological well-being, physical health, and interpersonal relations, but several fundamental questions remain. As much of the previous research has addressed generalized regulatory habits, far less is known about the ways in which individuals respond to emotions in daily life. The literature is particularly sparse in explorations of positive emotion regulation. In the current study, we provide an assessment of naturalistic experiences and regulation of emotion, both positive and negative in valence. Using an electronic experience sampling methodology, participants reported on their use of 40 regulatory strategies in response to 14 emotions for 10 consecutive days. On average, participants used 15 different regulatory strategies in response to negative emotions over this time, most frequently relying on acceptance, behavioral activation, and rumination. Participants used a similarly large repertoire of strategies, approximately 16 total, in response to positive emotions, particularly savoring, future focus, and behavioral activation. Participants' mood ratings following strategy use, however, indicated that the most frequently used strategies were often not the most effective strategies. The results of this study provide estimates of the frequency and effectiveness of a large number of emotion regulation strategies in response to both negative and positive emotions. Such findings characterize naturalistic emotion regulation, and estimates of normative emotion regulation processes are imperative to determining the ways in which deviations (e.g., small emotion regulation repertoires, insufficient attention to regulation of positive emotions) impact emotional functioning. PsycINFO Database Record (c) 2014 APA, all rights reserved.

DEC1/STRA13 is a key negative regulator of activation-induced proliferation of human B cells highly expressed in anergic cells.

PubMed

Camponeschi, Alessandro; Todi, Laura; Cristofoletti, Cristina; Lazzeri, Cristina; Carbonari, Maurizio; Mitrevski, Milica; Marrapodi, Ramona; Del Padre, Martina; Fiorilli, Massimo; Casato, Milvia; Visentini, Marcella

2018-06-01

The transcription factor DEC1/STRA13 (also known as BHLHE40 and SHARP2) is involved in a number of processes including inhibition of cell proliferation and delay of cell cycle, and is a negative regulator of B cell activation and development in mice. We show here that, unlike in mice, DEC1/STRA13 expression is induced in human naïve and memory resting B cells by activation through the B-cell receptor (BCR) or Toll-like receptor 9 (TLR9). siRNA silencing of DEC1/STRA13 increases the capacity of activated B cells to perform a high number of divisions after TLR9 ligation. This identifies DEC1/STRA13 as a critical negative regulator of clonal expansion of activated human B cells. We also show that DEC1/STRA13 is upregulated in human anergic CD21 low B cells clonally expanded in patients with HCV-associated mixed cryoglobulinemia, which fail to proliferate in response to BCR or TLR9 ligation. siRNA knockdown of DEC1/STRA13, however, fails to restore responsiveness to stimuli in these cells, although it might improve the proliferative capacity in a subset of anergic cells with less pronounced proliferative defect. Copyright © 2018 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Regulation of TRAIL-Medicated Apoptosis in Prostate Cancer by Overexpression of XIAP

DTIC Science & Technology

2005-01-01

induced resistance to TRAIL apoptosis. We used the nitric oxide donor DETANONOate and the NF-?B inhibitior Bay 11-7085 to inhibit NF-?B activity, and...negatively regulates DR5 expression and regulates resistance. We have demonstrated that the NO donor, DETANONOate , inhibited YY1 DNA-binding activity and... DETANONOate : (Z)-1-[2-(2-aminoethyl)-N-(2-ammonio-ethyl)amino]diazen-l-ium-1, 2-diolate DHT: 5-? dihydrotestosterone DR: death receptor DTT: 1,4

mTORC1 is necessary but mTORC2 and GSK3β are inhibitory for AKT3-induced axon regeneration in the central nervous system.

PubMed

Miao, Linqing; Yang, Liu; Huang, Haoliang; Liang, Feisi; Ling, Chen; Hu, Yang

2016-03-30

Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration.

The Phosphatidylinositol 3-Kinase/Akt Pathway Regulates Transforming Growth Factor-β Signaling by Destabilizing Ski and Inducing Smad7*

PubMed Central

Band, Arja M.; Björklund, Mia; Laiho, Marikki

2009-01-01

Ski is an oncoprotein that negatively regulates transforming growth factor (TGF)-β signaling. It acts as a transcriptional co-repressor by binding to TGF-β signaling molecules, Smads. Efficient TGF-β signaling is facilitated by rapid proteasome-mediated degradation of Ski by TGF-β. Here we report that Ski is phosphorylated by Akt/PKB kinase. Akt phosphorylates Ski on a highly conserved Akt motif at threonine 458 both in vitro and in vivo. The phosphorylation of Ski at threonine 458 is induced by Akt pathway activators including insulin, insulin-like growth factor-1, and hepatocyte growth factor. The phosphorylation of Ski causes its destabilization and reduces Ski-mediated inhibition of expression of another negative regulator of TGF-β, Smad7. Induction of Smad7 levels leads to inactivation of TGF-β receptors and TGF-β signaling cascade, as indicated by reduced induction of TGF-β target p15. Therefore, Akt modulates TGF-β signaling by temporarily adjusting the levels of two TGF-β pathway negative regulators, Ski and Smad7. These novel findings demonstrate that Akt pathway activation directly impacts TGF-β pathway. PMID:19875456

Prolyl Hydroxylase EGLN3 Regulates Skeletal Myoblast Differentiation through an NF-κB-dependent Pathway

PubMed Central

Fu, Jian; Taubman, Mark B.

2010-01-01

The egg-laying abnormal-9 (EGLN) prolyl hydroxylases have been shown to regulate the stability and thereby the activity of the α subunits of hypoxia-inducible factor (HIF) through its ability to catalyze their hydroxylation. We have previously shown that EGLN3 promotes differentiation of C2C12 skeletal myoblasts. However, the mechanism underlying this effect remains to be fully elucidated. Here, we report that exposure of C2C12 cells to dimethyl oxalylglycine (DMOG), desferrioxamine, and hypoxia, all inhibitors of prolyl hydroxylase activity, led to repression of C2C12 myogenic differentiation. Inactivation of HIF by expression of a HIF dominant-negative mutant or deletion of HIF-1α by RNA interference did not affect the inhibitory effect of DMOG, suggesting that the effect of DMOG is HIF-independent. Pharmacologic inactivation of EGLN3 hydroxylase resulted in activation of the canonical NF-κB pathway. The inhibitory effect of DMOG on myogenic differentiation was markedly impaired in C2C12 cells expressing a dominant-negative mutant of IκBα. Exogenous expression of wild-type EGLN3, but not its catalytically inactive mutant, significantly inhibited NF-κB activation induced by overexpressed TRAF2 or IκB kinase 2. In contrast, deletion of EGLN3 by small interfering RNAs led to activation of NF-κB. These data suggest that EGLN3 is a negative regulator of NF-κB, and its prolyl hydroxylase activity is required for this effect. Furthermore, wild-type EGLN3, but not its catalytically inactive mutant, potentiated myogenic differentiation. This study demonstrates a novel role for EGLN3 in the regulation of NF-κB and suggests that it is involved in mediating myogenic differentiation, which is HIF-independent. PMID:20089853

Negative Regulation of Leptin-induced Reactive Oxygen Species (ROS) Formation by Cannabinoid CB1 Receptor Activation in Hypothalamic Neurons.

PubMed

Palomba, Letizia; Silvestri, Cristoforo; Imperatore, Roberta; Morello, Giovanna; Piscitelli, Fabiana; Martella, Andrea; Cristino, Luigia; Di Marzo, Vincenzo

2015-05-29

The adipocyte-derived, anorectic hormone leptin was recently shown to owe part of its regulatory effects on appetite-regulating hypothalamic neuropeptides to the elevation of reactive oxygen species (ROS) levels in arcuate nucleus (ARC) neurons. Leptin is also known to exert a negative regulation on hypothalamic endocannabinoid levels and hence on cannabinoid CB1 receptor activity. Here we investigated the possibility of a negative regulation by CB1 receptors of leptin-mediated ROS formation in the ARC. Through pharmacological and molecular biology experiments we report data showing that leptin-induced ROS accumulation is 1) blunted by arachidonyl-2'-chloroethylamide (ACEA) in a CB1-dependent manner in both the mouse hypothalamic cell line mHypoE-N41 and ARC neuron primary cultures, 2) likewise blocked by a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, troglitazone, in a manner inhibited by T0070907, a PPAR-γ antagonist that also inhibited the ACEA effect on leptin, 3) blunted under conditions of increased endocannabinoid tone due to either pharmacological or genetic inhibition of endocannabinoid degradation in mHypoE-N41 and primary ARC neuronal cultures from MAGL(-/-) mice, respectively, and 4) associated with reduction of both PPAR-γ and catalase activity, which are reversed by both ACEA and troglitazone. We conclude that CB1 activation reverses leptin-induced ROS formation and hence possibly some of the ROS-mediated effects of the hormone by preventing PPAR-γ inhibition by leptin, with subsequent increase of catalase activity. This mechanism might underlie in part CB1 orexigenic actions under physiopathological conditions accompanied by elevated hypothalamic endocannabinoid levels. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The CRISPR/Cas9 system targeting EGFR exon 17 abrogates NF-κB activation via epigenetic modulation of UBXN1 in EGFRwt/vIII glioma cells.

PubMed

Huang, Kai; Yang, Chao; Wang, Qi-Xue; Li, Yan-Sheng; Fang, Chuan; Tan, Yan-Li; Wei, Jian-Wei; Wang, Yun-Fei; Li, Xin; Zhou, Jun-Hu; Zhou, Bing-Cong; Yi, Kai-Kai; Zhang, Kai-Liang; Li, Jie; Kang, Chun-Sheng

2017-03-01

Worldwide, glioblastoma (GBM) is the most lethal and frequent intracranial tumor. Despite decades of study, the overall survival of GBM patients remains unchanged. epidermal growth factor receptor (EGFR) amplification and gene mutation are thought to be negatively correlated with prognosis. In this study, we used proteomics to determine that UBXN1 is a negative downstream regulator of the EGFR mutation vIII (EGFRvIII). Via bioinformatics analysis, we found that UBXN1 is a factor that can improve glioma patients' overall survival time. We also determined that the down-regulation of UBXN1 is mediated by the upregulation of H3K27me3 in the presence of EGFRvIII. Because NF-κB can be negatively regulated by UBXN1, we believe that EGFRwt/vIII activates NF-κB by suppressing UBXN1 expression. Importantly, we used the latest genomic editing tool, CRISPR/Cas9, to knockout EGFRwt/vIII on exon 17 and further proved that UBXN1 is negatively regulated by EGFRwt/vIII. Furthermore, knockout of EGFR/EGFRvIII could benefit GBM in vitro and in vivo, indicating that CRISPR/Cas9 is a promising therapeutic strategy for both EGFR amplification and EGFR mutation-bearing patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Role of co-regulators in metabolic and transcriptional actions of thyroid hormone.

PubMed

Astapova, Inna

2016-04-01

Thyroid hormone (TH) controls a wide range of physiological processes through TH receptor (TR) isoforms. Classically, TRs are proposed to function as tri-iodothyronine (T3)-dependent transcription factors: on positively regulated target genes, unliganded TRs mediate transcriptional repression through recruitment of co-repressor complexes, while T3 binding leads to dismissal of co-repressors and recruitment of co-activators to activate transcription. Co-repressors and co-activators were proposed to play opposite roles in the regulation of negative T3 target genes and hypothalamic-pituitary-thyroid axis, but exact mechanisms of the negative regulation by TH have remained elusive. Important insights into the roles of co-repressors and co-activators in different physiological processes have been obtained using animal models with disrupted co-regulator function. At the same time, recent studies interrogating genome-wide TR binding have generated compelling new data regarding effects of T3, local chromatin structure, and specific response element configuration on TR recruitment and function leading to the proposal of new models of transcriptional regulation by TRs. This review discusses data obtained in various mouse models with manipulated function of nuclear receptor co-repressor (NCoR or NCOR1) and silencing mediator of retinoic acid receptor and thyroid hormone receptor (SMRT or NCOR2), and family of steroid receptor co-activators (SRCs also known as NCOAs) in the context of TH action, as well as insights into the function of co-regulators that may emerge from the genome-wide TR recruitment analysis. © 2016 Society for Endocrinology.

Calcineurin/NFAT signalling inhibits myeloid haematopoiesis.

PubMed

Fric, Jan; Lim, Clarice X F; Koh, Esther G L; Hofmann, Benjamin; Chen, Jinmiao; Tay, Hock Soon; Mohammad Isa, Siti Aminah Bte; Mortellaro, Alessandra; Ruedl, Christiane; Ricciardi-Castagnoli, Paola

2012-04-01

Nuclear factor of activated T cells (NFAT) comprises a family of transcription factors that regulate T cell development, activation and differentiation. NFAT signalling can also mediate granulocyte and dendritic cell (DC) activation, but it is unknown whether NFAT influences their development from progenitors. Here, we report a novel role for calcineurin/NFAT signalling as a negative regulator of myeloid haematopoiesis. Reconstituting lethally irradiated mice with haematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment. Culturing bone marrow cells in media supplemented with Flt3-L in the presence of the calcineurin/NFAT inhibitor Cyclosporin A increased numbers of differentiated DC. Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis. In conclusion, these results provide evidence that calcineurin/NFAT signalling negatively regulates myeloid lineage development. The finding that inhibition of NFAT enhances myeloid development provides a novel insight into understanding how the treatment with drugs targeting calcineurin/NFAT signalling influence the homeostasis of the innate immune system. Copyright © 2012 EMBO Molecular Medicine.

The Prospective Joint Effects of Self-Regulation and Impulsive Processes on Early Adolescence Alcohol Use

PubMed Central

O’Connor, Roisin M.; Colder, Craig R.

2015-01-01

Objective: Dual-process models propose that behavior is influenced by the interactive effect of impulsive (automatic) and selfregulatory (controlled) processes. Elaborations of this model posit that the effect of impulsive processes on alcohol use is influenced by capacity and motivation to self-regulate. The interactive effect of these three processes on drinking has not previously been tested. The goal of this study was to provide a developmental extension of this model to early adolescent alcohol use and to test the three-way interaction between impulsive processes (implicit alcohol cognition), self-regulatory capacity (inhibitory and activation control), and self-regulatory motivation (negative alcohol outcome expectancies [AOE]) in a 1-year prospective prediction of adolescent alcohol use. Method: Adolescents (N = 325; 54% girls, mean age = 13.6 years at baseline) completed the Single Category Implicit Association Test and self-reports of alcohol expectancies and use. Inhibitory and activation control were based on parental report. Results: Negative AOE and inhibitory/activation control were supported as moderators of the effect of implicit alcohol cognition on 1-year prospective alcohol use. As expected, weak implicit negative alcohol cognition was associated with elevated alcohol use when both negative AOE and inhibitory control were low. Contrary to hypothesis, when activation control was high, weak implicit negative alcohol cognition was unrelated to alcohol use if negative AOE were high (p = .72) (vs. low, p < .01).Activation control may reflect the ability to plan ahead and act pro-socially. Conclusions: Our study supports current theory suggesting alcohol use is influenced by a complex interplay of impulsive and self-regulatory processes. PMID:26562596

Neurohumoral Mechanisms Associated with Orthostasis: Reaffirmation of the Significant Contribution of the Heart Rate Response

DTIC Science & Technology

2014-06-30

baroreceptor stimu- lation (i.e., lower arterial blood pressure ) suggests an association between a depressed baroreflex response and development of...orthostatic tolerance, blood pressure regulation, lower body negative pressure , parasympathetic activity, sympathetic activity, propranolol, atropine...body negative pressure (LBNP) so that comparisons of physiology in individuals with high and low tolerance to central hypovolemia could be studied at

Hypothalamic nutrient sensing activates a forebrain-hindbrain neuronal circuit to regulate glucose production in vivo.

PubMed

Lam, Carol K L; Chari, Madhu; Rutter, Guy A; Lam, Tony K T

2011-01-01

Hypothalamic nutrient sensing regulates glucose production, but the neuronal circuits involved remain largely unknown. Recent studies underscore the importance of N-methyl-d-aspartate (NMDA) receptors in the dorsal vagal complex in glucose regulation. These studies raise the possibility that hypothalamic nutrient sensing activates a forebrain-hindbrain NMDA-dependent circuit to regulate glucose production. We implanted bilateral catheters targeting the mediobasal hypothalamus (MBH) (forebrain) and dorsal vagal complex (DVC) (hindbrain) and performed intravenous catheterizations to the same rat for infusion and sampling purposes. This model enabled concurrent selective activation of MBH nutrient sensing by either MBH delivery of lactate or an adenovirus expressing the dominant negative form of AMPK (Ad-DN AMPK α2 [D¹⁵⁷A]) and inhibition of DVC NMDA receptors by either DVC delivery of NMDA receptor blocker MK-801 or an adenovirus expressing the shRNA of NR1 subunit of NMDA receptors (Ad-shRNA NR1). Tracer-dilution methodology and the pancreatic euglycemic clamp technique were performed to assess changes in glucose kinetics in the same conscious, unrestrained rat in vivo. MBH lactate or Ad-DN AMPK with DVC saline increased glucose infusion required to maintain euglycemia due to an inhibition of glucose production during the clamps. However, DVC MK-801 negated the ability of MBH lactate or Ad-DN AMPK to increase glucose infusion or lower glucose production. Molecular knockdown of DVC NR1 of NMDA receptor via Ad-shRNA NR1 injection also negated MBH Ad-DN AMPK to lower glucose production. Molecular and pharmacological inhibition of DVC NMDA receptors negated hypothalamic nutrient sensing mechanisms activated by lactate metabolism or AMPK inhibition to lower glucose production. Thus, DVC NMDA receptor is required for hypothalamic nutrient sensing to lower glucose production and that hypothalamic nutrient sensing activates a forebrain-hindbrain circuit to lower glucose production.

Procyanidin dimer B2-mediated IRAK-M induction negatively regulates TLR4 signaling in macrophages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sung, Nak-Yun; Yang, Mi-So; Song, Du-Sub

Highlights: •Pro B2 elevated the expression of IRAK-M, a negative regulator of TLR signaling. •LPS-induced expression of cell surface molecules was inhibited by Pro B2. •LPS-induced production of pro-inflammatory cytokines was inhibited by Pro B2. •Pro B2 inhibited LPS-induced activation of MAPKs and NF-κB through IRAK-M. •Pro B2 inactivated naïve T cells by inhibiting LPS-induced cytokines via IRAK-M. -- Abstract: Polyphenolic compounds have been found to possess a wide range of physiological activities that may contribute to their beneficial effects against inflammation-related diseases; however, the molecular mechanisms underlying this anti-inflammatory activity are not completely characterized, and many features remain tomore » be elucidated. In this study, we investigated the molecular basis for the down-regulation of toll-like receptor 4 (TLR4) signal transduction by procyanidin dimer B2 (Pro B2) in macrophages. Pro B2 markedly elevated the expression of the interleukin (IL)-1 receptor-associated kinase (IRAK)-M protein, a negative regulator of TLR signaling. Lipopolysaccharide (LPS)-induced expression of cell surface molecules (CD80, CD86, and MHC class I/II) and production of pro-inflammatory cytokines (tumor necrosis factor-α, IL-1β, IL-6, and IL-12p70) were inhibited by Pro B2, and this action was prevented by IRAK-M silencing. In addition, Pro B2-treated macrophages inhibited LPS-induced activation of mitogen-activated protein kinases such as extracellular signal-regulated kinase 1/2, p38, and c-Jun N-terminal kinase and the translocation of nuclear factor κB and p65 through IRAK-M. We also found that Pro B2-treated macrophages inactivated naïve T cells by inhibiting LPS-induced interferon-γ and IL-2 secretion through IRAK-M. These novel findings provide new insights into the understanding of negative regulatory mechanisms of the TLR4 signaling pathway and the immune-pharmacological role of Pro B2 in the immune response against the development and progression of many chronic diseases.« less

NK cell activation: distinct stimulatory pathways counterbalancing inhibitory signals.

PubMed

Bakker, A B; Wu, J; Phillips, J H; Lanier, L L

2000-01-01

A delicate balance between positive and negative signals regulates NK cell effector function. Activation of NK cells may be initiated by the triggering of multiple adhesion or costimulatory molecules, and can be counterbalanced by inhibitory signals induced by receptors for MHC class I. A common pathway of inhibitory signaling is provided by immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in the cytoplasmic domains of these receptors which mediate the recruitment of SH2 domain-bearing tyrosine phosphate-1 (SHP-1). In contrast to the extensive progress that has been made regarding the negative regulation of NK cell function, our knowledge of the signals that activate NK cells is still poor. Recent studies of the activating receptor complexes have shed new light on the induction of NK cell effector function. Several NK receptors using novel adaptors with immunoreceptor tyrosine-based activation motifs (ITAMs) and with PI 3-kinase recruiting motifs have been implicated in NK cell stimulation.

Mindfulness meditation improves emotion regulation and reduces drug abuse.

PubMed

Tang, Yi-Yuan; Tang, Rongxiang; Posner, Michael I

2016-06-01

The core clinical symptoms of addiction include an enhanced incentive for drug taking (craving), impaired self-control (impulsivity and compulsivity), emotional dysregulation (negative mood) and increased stress reactivity. Symptoms related to impaired self-control involve reduced activity in anterior cingulate cortex (ACC), adjacent prefrontal cortex (mPFC) and other brain areas. Behavioral training such as mindfulness meditation can increase the function of control networks including those leading to improved emotion regulation and thus may be a promising approach for the treatment of addiction. In a series of randomized controlled trials (RCTs), we tested whether increased ACC/mPFC activity is related to better self-control abilities in executive functions, emotion regulation and stress response in healthy and addicted populations. After a brief mindfulness training (Integrative Body-Mind Training, IBMT), we used the Positive and Negative Affect Schedule (PANAS) and Profile of Mood States (POMS) to measure emotion regulation, salivary cortisol for the stress response and fMRI for brain functional and DTI structural changes. Relaxation training was used to serve as an active control. In both smokers and nonsmokers, improved self-control abilities in emotion regulation and stress reduction were found after training and these changes were related to increased ACC/mPFC activity following training. Compared with nonsmokers, smokers showed reduced ACC/mPFC activity in the self-control network before training, and these deficits were ameliorated after training. These results indicate that promoting emotion regulation and improving ACC/mPFC brain activity can help for addiction prevention and treatment. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Neuronal migration is regulated by endogenous RNAi and chromatin-binding factor ZFP-1/AF10 in Caenorhabditis elegans.

PubMed

Kennedy, Lisa M; Grishok, Alla

2014-05-01

Endogenous short RNAs and the conserved plant homeodomain (PHD) zinc-finger protein ZFP-1/AF10 regulate overlapping sets of genes in Caenorhabditis elegans, which suggests that they control common biological pathways. We have shown recently that the RNAi factor RDE-4 and ZFP-1 negatively modulate transcription of the insulin/PI3 signaling-dependent kinase PDK-1 to promote C. elegans fitness. Moreover, we have demonstrated that the insulin/IGF-1-PI3K-signaling pathway regulates the activity of the DAF-16/FOXO transcription factor in the hypodermis to nonautonomously promote the anterior migrations of the hermaphrodite-specific neurons (HSNs) during embryogenesis of C. elegans. In this study, we implicate the PHD-containing isoform of ZFP-1 and endogenous RNAi in the regulation of HSN migration. ZFP-1 affects HSN migration in part through its negative effect on pdk-1 transcription and modulation of downstream DAF-16 activity. We also identify a novel role for ZFP-1 and RNAi pathway components, including RDE-4, in the regulation of HSN migration in parallel with DAF-16. Therefore, the coordinated activities of DAF-16, ZFP-1, and endogenous RNAi contribute to gene regulation during development to ensure proper neuronal positioning.

Neuronal Migration Is Regulated by Endogenous RNAi and Chromatin-Binding Factor ZFP-1/AF10 in Caenorhabditis elegans

PubMed Central

Kennedy, Lisa M.; Grishok, Alla

2014-01-01

Endogenous short RNAs and the conserved plant homeodomain (PHD) zinc-finger protein ZFP-1/AF10 regulate overlapping sets of genes in Caenorhabditis elegans, which suggests that they control common biological pathways. We have shown recently that the RNAi factor RDE-4 and ZFP-1 negatively modulate transcription of the insulin/PI3 signaling-dependent kinase PDK-1 to promote C. elegans fitness. Moreover, we have demonstrated that the insulin/IGF-1-PI3K-signaling pathway regulates the activity of the DAF-16/FOXO transcription factor in the hypodermis to nonautonomously promote the anterior migrations of the hermaphrodite-specific neurons (HSNs) during embryogenesis of C. elegans. In this study, we implicate the PHD-containing isoform of ZFP-1 and endogenous RNAi in the regulation of HSN migration. ZFP-1 affects HSN migration in part through its negative effect on pdk-1 transcription and modulation of downstream DAF-16 activity. We also identify a novel role for ZFP-1 and RNAi pathway components, including RDE-4, in the regulation of HSN migration in parallel with DAF-16. Therefore, the coordinated activities of DAF-16, ZFP-1, and endogenous RNAi contribute to gene regulation during development to ensure proper neuronal positioning. PMID:24558261

TCPs, WUSs, and WINDs: families of transcription factors that regulate shoot meristem formation, stem cell maintenance, and somatic cell differentiation.

PubMed

Ikeda, Miho; Ohme-Takagi, Masaru

2014-01-01

In contrast to somatic mammalian cells, which cannot alter their fate, plant cells can dedifferentiate to form totipotent callus cells and regenerate a whole plant, following treatment with specific phytohormones. However, the regulatory mechanisms and key factors that control differentiation-dedifferentiation and cell totipotency have not been completely clarified in plants. Recently, several plant transcription factors that regulate meristem formation and dedifferentiation have been identified and include members of the TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP), WUSCHEL (WUS), and WOUND INDUCED DEDIFFERENTIATION (WIND1) families. WUS and WIND positively control plant cell totipotency, while TCP negatively controls it. Interestingly, TCP is a transcriptional activator that acts as a negative regulator of shoot meristem formation, and WUS is a transcriptional repressor that positively maintains totipotency of the stem cells of the shoot meristem. We describe here the functions of TCP, WUS, and WIND transcription factors in the regulation of differentiation-dedifferentiation by positive and negative transcriptional regulators.

RANK-c attenuates aggressive properties of ER-negative breast cancer by inhibiting NF-κB activation and EGFR signaling.

PubMed

Sirinian, Chaido; Papanastasiou, Anastasios D; Schizas, Michail; Spella, Magda; Stathopoulos, Georgios T; Repanti, Maria; Zarkadis, Ioannis K; King, Tari A; Kalofonos, Haralabos P

2018-05-29

The RANK/RANKL axis emerges as a key regulator of breast cancer initiation, progression, and metastasis. RANK-c is a RANK receptor isoform produced through alternative splicing of the TNFRSF11A (RANK) gene and a dominant-negative regulator of RANK-induced nuclear factor-κB (NF-κB) activation. Here we report that RANK-c transcript is expressed in 3.2% of cases in The Cancer Genome Atlas breast cancer cohort evenly between ER-positive and ER-negative cases. Nevertheless, the ratio of RANK to RANK-c (RANK/RANK-c) is increased in ER-negative breast cancer cell lines compared to ER-positive breast cancer cell lines. In addition, forced expression of RANK-c in ER-negative breast cancer cell lines inhibited stimuli-induced NF-κB activation and attenuated migration, invasion, colony formation, and adhesion of cancer cells. Further, RANK-c expression in MDA-MB-231 cells inhibited lung metastasis and colonization in vivo. The RANK-c-mediated inhibition of cancer cell aggressiveness and nuclear factor-κB (NF-κB) activation in breast cancer cells seems to rely on a RANK-c/TNF receptor-associated factor-2 (TRAF2) protein interaction. This was further confirmed by a mutated RANK-c that is unable to interact with TRAF2 and abolishes the ability to attenuate NF-κB activation, migration, and invasion. Additional protein interaction characterization revealed epidermal growth factor receptor (EGFR) as a novel interacting partner for RANK-c in breast cancer cells with a negative effect on EGFR phosphorylation and EGF-dependent downstream signaling pathway activation. Our findings further elucidate the complex molecular biology of the RANKL/RANK system in breast cancer and provide preliminary data for RANK-c as a possible marker for disease progression and aggressiveness.

How children use drawing to regulate their emotions.

PubMed

Drake, Jennifer E; Winner, Ellen

2013-01-01

We examined two ways in which drawing may function to elevate mood in children-venting (expressing negative feelings) and distraction (expressing something unrelated to the negative feelings). We examined the effectiveness of drawing as an emotion regulator when drawing is used to vent versus distract (Study 1) and tested whether the effects found are specific to the activity of creating one's own drawing or generalisable to a drawing activity in which children had to copy another's drawing (Study 2). To induce a negative mood, we asked children to think of a disappointing event. Mood was assessed before and after the assigned activity. In both studies, mood improved significantly more in the distract than in the vent or copy condition. Study 1 demonstrates that drawing improves mood in children via distraction and not via venting. Study 2 demonstrates that this effect is specific to a drawing task in which an image is freely constructed. When a copying task is used, the effect disappears.

Evidence of successful modulation of brain activation and subjective experience during reappraisal of negative emotion in unmedicated depression.

PubMed

Dillon, Daniel Gerard; Pizzagalli, Diego Andrea

2013-05-30

Functional magnetic resonance imaging (fMRI) was used to examine cognitive regulation of negative emotion in 12 unmedicated patients with major depressive disorder (MDD) and 24 controls. The participants used reappraisal to increase (real condition) and reduce (photo condition) the personal relevance of negative and neutral pictures during fMRI as valence ratings were collected; passive viewing (look condition) served as a baseline. Reappraisal was not strongly affected by MDD. Ratings indicated that both groups successfully reappraised negative emotional experience. Both groups also showed better memory for negative vs. neutral pictures 2 weeks later. Across groups, increased brain activation was observed on negative/real vs. negative/look and negative/photo trials in left dorsolateral prefrontal cortex (DLPFC), rostral anterior cingulate, left parietal cortex, caudate, and right amygdala. Depressive severity was inversely correlated with activation modulation in the left DLPFC, right amygdala, and right cerebellum during negative reappraisal. The lack of group differences suggests that depressed adults can modulate the brain activation and subjective experience elicited by negative pictures when given clear instructions. However, the negative relationship between depression severity and effects of reappraisal on brain activation indicates that group differences may be detectable in larger samples of more severely depressed participants. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Novel mutations in the inhibitory adaptor protein LNK drive JAK-STAT signaling in patients with myeloproliferative neoplasms

PubMed Central

Oh, Stephen T.; Simonds, Erin F.; Jones, Carol; Hale, Matthew B.; Goltsev, Yury; Gibbs, Kenneth D.; Merker, Jason D.; Zehnder, James L.; Nolan, Garry P.

2010-01-01

Dysregulated Janus kinase–signal transducer and activator of transcription (JAK-STAT) signaling due to activation of tyrosine kinases is a common feature of myeloid malignancies. Here we report the first human disease-related mutations in the adaptor protein LNK, a negative regulator of JAK-STAT signaling, in 2 patients with JAK2 V617F–negative myeloproliferative neoplasms (MPNs). One patient exhibited a 5 base-pair deletion and missense mutation leading to a premature stop codon and loss of the pleckstrin homology (PH) and Src homology 2 (SH2) domains. A second patient had a missense mutation (E208Q) in the PH domain. BaF3-MPL cells transduced with these LNK mutants displayed augmented and sustained thrombopoietin-dependent growth and signaling. Primary samples from MPN patients bearing LNK mutations exhibited aberrant JAK-STAT activation, and cytokine-responsive CD34+ early progenitors were abnormally abundant in both patients. These findings indicate that JAK-STAT activation due to loss of LNK negative feedback regulation is a novel mechanism of MPN pathogenesis. PMID:20404132

A minimal mathematical model combining several regulatory cycles from the budding yeast cell cycle.

PubMed

Sriram, K; Bernot, G; Képès, F

2007-11-01

A novel topology of regulatory networks abstracted from the budding yeast cell cycle is studied by constructing a simple nonlinear model. A ternary positive feedback loop with only positive regulations is constructed with elements that activates the subsequent element in a clockwise fashion. A ternary negative feedback loop with only negative regulations is constructed with the elements that inhibit the subsequent element in an anticlockwise fashion. Positive feedback loop exhibits bistability, whereas the negative feedback loop exhibits limit cycle oscillations. The novelty of the topology is that the corresponding elements in these two homogeneous feedback loops are linked by the binary positive feedback loops with only positive regulations. This results in the emergence of mixed feedback loops in the network that displays complex behaviour like the coexistence of multiple steady states, relaxation oscillations and chaos. Importantly, the arrangement of the feedback loops brings in the notion of checkpoint in the model. The model also exhibits domino-like behaviour, where the limit cycle oscillations take place in a stepwise fashion. As the aforementioned topology is abstracted from the budding yeast cell cycle, the events that govern the cell cycle are considered for the present study. In budding yeast, the sequential activation of the transcription factors, cyclins and their inhibitors form mixed feedback loops. The transcription factors that involve in the positive regulation in a clockwise orientation generates ternary positive feedback loop, while the cyclins and their inhibitors that involve in the negative regulation in an anticlockwise orientation generates ternary negative feedback loop. The mutual regulation between the corresponding elements in the transcription factors and the cyclins and their inhibitors generates binary positive feedback loops. The bifurcation diagram constructed for the whole system can be related to the different events of the cell cycle in terms of dynamical system theory. The checkpoint mechanism that plays an important role in different phases of the cell cycle are accounted for by silencing appropriate feedback loops in the model.

Staying Cool when Things Get Hot: Emotion Regulation Modulates Neural Mechanisms of Memory Encoding

PubMed Central

Hayes, Jasmeet Pannu; Morey, Rajendra A.; Petty, Christopher M.; Seth, Srishti; Smoski, Moria J.; McCarthy, Gregory; LaBar, Kevin S.

2010-01-01

During times of emotional stress, individuals often engage in emotion regulation to reduce the experiential and physiological impact of negative emotions. Interestingly, emotion regulation strategies also influence memory encoding of the event. Cognitive reappraisal is associated with enhanced memory while expressive suppression is associated with impaired explicit memory of the emotional event. However, the mechanism by which these emotion regulation strategies affect memory is unclear. We used event-related fMRI to investigate the neural mechanisms that give rise to memory formation during emotion regulation. Twenty-five participants viewed negative pictures while alternately engaging in cognitive reappraisal, expressive suppression, or passive viewing. As part of the subsequent memory design, participants returned to the laboratory two weeks later for a surprise memory test. Behavioral results showed a reduction in negative affect and a retention advantage for reappraised stimuli relative to the other conditions. Imaging results showed that successful encoding during reappraisal was uniquely associated with greater co-activation of the left inferior frontal gyrus, amygdala, and hippocampus, suggesting a possible role for elaborative encoding of negative memories. This study provides neurobehavioral evidence that engaging in cognitive reappraisal is advantageous to both affective and mnemonic processes. PMID:21212840

Endocannabinoid Signaling, Glucocorticoid-Mediated Negative Feedback and Regulation of the HPA Axis

PubMed Central

Hill, M. N.; Tasker, J. G.

2012-01-01

The hypothalamic-pituitary-adrenal (HPA) axis regulates the outflow of glucocorticoid hormones under basal conditions and in response to stress. Within the last decade, a large body of evidence has mounted indicating that the endocannabinoid system is involved in the central regulation of the stress response; however, the specific role endocannabinoid signalling plays in phases of HPA axis regulation, or the neural sites of action mediating this regulation, was not mapped out until recently. This review aims to collapse the current state of knowledge regarding the role of the endocannabinoid system in the regulation of the HPA axis to put together a working model of how and where endocannabinoids act within the brain to regulate outflow of the HPA axis. Specifically, we discuss the role of the endocannabinoid system in the regulation of the HPA axis under basal conditions, activation in response to acute stress and glucocorticoid-mediated negative feedback. Interestingly, there appears to be some anatomical specificity to the role of the endocannabinoid system in each phase of HPA axis regulation, as well as distinct roles of both anandamide and 2-arachidonoylglycerol in these phases. Ultimately, the current level of information indicates that endocannabinoid signalling acts to suppress HPA axis activity through concerted actions within the prefrontal cortex, amygdala and hypothalamus. PMID:22214537

Synergistic role of Sprouty2 inactivation and c-Met up-regulation in mouse and human hepatocarcinogenesis.

PubMed

Lee, Susie A; Ladu, Sara; Evert, Matthias; Dombrowski, Frank; De Murtas, Valentina; Chen, Xin; Calvisi, Diego F

2010-08-01

Sprouty2 (Spry2), a negative feedback regulator of the Ras/mitogen-activated protein kinase (MAPK) pathway, is frequently down-regulated in human hepatocellular carcinoma (HCC). We tested the hypothesis that loss of Spry2 cooperates with unconstrained activation of the c-Met protooncogene to induce hepatocarcinogenesis via in vitro and in vivo approaches. We found coordinated down-regulation of Spry2 protein expression and activation of c-Met as well as its downstream effectors extracellular signal-regulated kinase (ERK) and v-akt murine thymoma viral oncogene homolog (AKT) in a subset of human HCC samples with poor outcome. Mechanistic studies revealed that Spry2 function is disrupted in human HCC via multiple mechanisms at both transcriptional and post-transcriptional level, including promoter hypermethylation, loss of heterozygosity, and proteosomal degradation by neural precursor cell expressed, developmentally down-regulated 4 (NEDD4). In HCC cell lines, Spry2 overexpression inhibits c-Met-induced cell proliferation as well as ERK and AKT activation, whereas loss of Spry2 potentiates c-Met signaling. Most importantly, we show that blocking Spry2 activity via a dominant negative form of Spry2 cooperates with c-Met to promote hepatocarcinogenesis in the mouse liver by sustaining proliferation and angiogenesis. The tumors exhibited high levels of activated ERK and AKT, recapitulating the subgroup of human HCC with a clinically aggressive phenotype. The occurrence of frequent genetic, epigenetic, and biochemical events leading to Spry2 inactivation provides solid evidence that Spry2 functions as a tumor suppressor gene in liver cancer. Coordinated deregulation of Spry2 and c-Met signaling may be a pivotal oncogenic mechanism responsible for unrestrained activation of ERK and AKT pathways in human hepatocarcinogenesis.

Repression of enhancer II activity by a negative regulatory element in the hepatitis B virus genome.

PubMed Central

Lo, W Y; Ting, L P

1994-01-01

Enhancer II of human hepatitis B virus has dual functions in vivo. Located at nucleotides (nt) 1646 to 1741, it can stimulate the surface and X promoters from a downstream position. Moreover, the same sequence can also function as upstream regulatory element that activates the core promoter in a position- and orientation-dependent manner. In this study, we report the identification and characterization of a negative regulatory element (NRE) upstream of enhancer II (nt 1613 to 1636) which can repress both the enhancer and upstream stimulatory function of the enhancer II sequence in differentiated liver cells. This NRE has marginal inhibitory effect by itself but a strong repressive function in the presence of a functional enhancer II. Mutational analysis reveals that sequence from nt 1616 to 1621 is required for repression of enhancer activity by the NRE. Gel shift analysis reveals that this negative regulatory region can be recognized by a specific protein factor(s) present at the 0.4 M NaCl fraction of HepG2 nuclear extracts. The discovery of the NRE indicates that HBV gene transcription is controlled by combined effects of both positive and negative regulation. It also provides a unique system with which to study the mechanism of negative regulation of gene expression. Images PMID:8107237

Long non-coding RNA GAS5 aggravates hypoxia injury in PC-12 cells via down-regulating miR-124.

PubMed

Hu, Xiaoli; Liu, Juan; Zhao, Gang; Zheng, Jiaping; Qin, Xia

2018-05-08

One important feature of cerebral ischemia is hypoxia injury in nerve cells. Growth arrest-specific transcript 5 (GAS5) is widely reported as a tumor suppressor gene; however, the investigations about its role in cerebrovascular disease are relatively rare. This study was aimed to explore the impact of GAS5 on hypoxia response in nervous cells. PC-12 cells were incubated under anoxic condition to induce hypoxia injury. Regulatory effects of GAS5 on miR-124 and miR-124 on ICAM-1 expression were assessed by qRT-PCR and/or Western blot. Targeting effect of miR-124 on ICAM-1 3'-untranslated regions (UTR) was evaluated through dual luciferase activity assay. The potential regulatory mechanism on hypoxia injury in PC-12 cells was assessed by detecting key elements of NF-κB and Notch signaling pathways using Western blot. GAS5 ectopic expression accentuated hypoxia injury in PC-12 cells. miR-124 expression was negatively regulated by GAS5 expression. Cells with overexpressions of GAS5 and miR-124 alleviated hypoxia injury as in compassion with cells only with GAS5 overexpression. ICAM-1 expression was negatively regulated by miR-124 expression. ICAM-1 was a functional target of miR-124. ICAM-1 overexpression aggravated hypoxia injury, but inversely, ICAM-1 silence diminished hypoxia damage. Besides, ICAM-1 expression was negatively related with activation of NF-κB and Notch pathways. GAS5-miR-124-ICAM-1 axis could regulate hypoxia injury in PC-12 cells. GAS5 might aggravate hypoxia injury via down-regulating miR-124, then up-regulating ICAM-1, and further enhancing activations of NF-κB and Notch pathways. © 2018 Wiley Periodicals, Inc.

Rga6 is a fission yeast Rho GAP involved in Cdc42 regulation of polarized growth

PubMed Central

Revilla-Guarinos, M. T.; Martín-García, Rebeca; Villar-Tajadura, M. Antonia; Estravís, Miguel; Coll, Pedro M.; Pérez, Pilar

2016-01-01

Active Cdc42 is essential for the establishment of polarized growth. This GTPase is negatively regulated by the GTPase-activating proteins (GAPs), which are important for the spatial specificity of Cdc42 function. Rga4 is the only GAP described as negative regulator of fission yeast Cdc42. We report here that Rga6, another fission yeast Cdc42 GAP, shares some functions with Rga4. Cells lacking Rga6 are viable but slightly shorter and broader than wild type, and cells lacking Rga6 and Rga4 simultaneously are rounded. In these cells, active Cdc42 is observed all around the membrane. These additive effects indicate that both GAPs collaborate in the spatial regulation of active Cdc42. Rga6 localizes to the plasma membrane, forming clusters different from those formed by Rga4. A polybasic region at the Rga6 C-terminus is responsible for its membrane localization. Rga6-GFP fluorescence decreases considerably at the growing tips, and this decrease is dependent on the actin cables. Of note, in the absence of Rga6, the amplitude of active Cdc42 oscillations at the tips decreases, and less GTP-Cdc42 accumulates at the new end of the cells. We propose that Rga6 collaborates with Rga4 to spatially restrict active Cdc42 at the cell tips and maintain cell dimensions. PMID:26960792

Thioredoxin-1 Negatively Modulates ADAM17 Activity Through Direct Binding and Indirect Reductive Activity.

PubMed

Granato, Daniela C; E Costa, Rute A P; Kawahara, Rebeca; Yokoo, Sami; Aragão, Annelize Z; Domingues, Romênia R; Pauletti, Bianca A; Honorato, Rodrigo V; Fattori, Juliana; Figueira, Ana Carolina M; Oliveira, Paulo S L; Consonni, Silvio R; Fernandes, Denise; Laurindo, Francisco; Hansen, Hinrich P; Paes Leme, Adriana F

2018-02-27

A disintegrin and metalloprotease 17 (ADAM17) modulates signaling events by releasing surface protein ectodomains such as TNFa and the EGFR-ligands. We have previously characterized cytoplasmic thioredoxin-1 (Trx-1) as a partner of ADAM17 cytoplasmic domain. Still, the mechanism of ADAM17 regulation by Trx-1 is unknown, and it has become of paramount importance to assess the degree of influence that Trx-1 has on metalloproteinase ADAM17. Combining discovery and targeted proteomic approaches, we uncovered that Trx-1 negatively regulates ADAM17 by direct and indirect effect. We performed cell-based assays with synthetic peptides and site-directed mutagenesis, and we demonstrated that the interaction interface of Trx-1 and ADAM17 is important for the negative regulation of ADAM17 activity. However, both Trx-1 K72A and catalytic site mutant Trx-1 C32/35S rescued ADAM17 activity, although the interaction with Trx-1 C32/35S was unaffected, suggesting an indirect effect of Trx-1. We confirmed that the Trx-1 C32/35S mutant showed diminished reductive capacity, explaining this indirect effect on increasing ADAM17 activity through oxidant levels. Interestingly, Trx-1 K72A mutant showed similar oxidant levels to Trx-1 C32/35S , even though its catalytic site was preserved. We further demonstrated that the general reactive oxygen species inhibitor, Nacetylcysteine (NAC), maintained the regulation of ADAM17 dependent of Trx-1 reductase activity levels; whereas the electron transport chain modulator, rotenone, abolished Trx-1 effect on ADAM17 activity. We show for the first time that the mechanism of ADAM17 regulation, Trx-1 dependent, can be by direct interaction and indirect effect, bringing new insights into the cross-talk between isomerases and mammalian metalloproteinases. This unexpected Trx-1 K72A behavior was due to more dimer formation and, consequently, the reduction of its Trx-1 reductase activity, evaluated through dimer verification, by gel filtration and mass spectrometry analysis. Antioxid. Redox Signal. 00, 000-000.

Cytosolic Nucleotides Block and Regulate the Arabidopsis Vacuolar Anion Channel AtALMT9*

PubMed Central

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-01-01

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al3+ to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. PMID:25028514

Cytosolic nucleotides block and regulate the Arabidopsis vacuolar anion channel AtALMT9.

PubMed

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-09-12

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al(3+) to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

CREB activity in dopamine D1 receptor expressing neurons regulates cocaine-induced behavioral effects

PubMed Central

Bilbao, Ainhoa; Rieker, Claus; Cannella, Nazzareno; Parlato, Rosanna; Golda, Slawomir; Piechota, Marcin; Korostynski, Michal; Engblom, David; Przewlocki, Ryszard; Schütz, Günther; Spanagel, Rainer; Parkitna, Jan R.

2014-01-01

It is suggested that striatal cAMP responsive element binding protein (CREB) regulates sensitivity to psychostimulants. To test the cell-specificity of this hypothesis we examined the effects of a dominant-negative CREB protein variant expressed in dopamine receptor D1 (D1R) neurons on cocaine-induced behaviors. A transgenic mouse strain was generated by pronuclear injection of a BAC-derived transgene harboring the A-CREB sequence under the control of the D1R gene promoter. Compared to wild-type, drug-naïve mutants showed moderate alterations in gene expression, especially a reduction in basal levels of activity-regulated transcripts such as Arc and Egr2. The behavioral responses to cocaine were elevated in mutant mice. Locomotor activity after acute treatment, psychomotor sensitization after intermittent drug injections and the conditioned locomotion after saline treatment were increased compared to wild-type littermates. Transgenic mice had significantly higher cocaine conditioned place preference, displayed normal extinction of the conditioned preference, but showed an augmented cocaine-seeking response following priming-induced reinstatement. This enhanced cocaine-seeking response was associated with increased levels of activity-regulated transcripts and prodynorphin. The primary reinforcing effects of cocaine were not altered in the mutant mice as they did not differ from wild-type in cocaine self-administration under a fixed ratio schedule at the training dose. Collectively, our data indicate that expression of a dominant-negative CREB variant exclusively in neurons expressing D1R is sufficient to recapitulate the previously reported behavioral phenotypes associated with virally expressed dominant-negative CREB. PMID:24966820

The paracaspase MALT1 cleaves HOIL1 reducing linear ubiquitination by LUBAC to dampen lymphocyte NF-κB signalling

PubMed Central

Klein, Theo; Fung, Shan-Yu; Renner, Florian; Blank, Michael A.; Dufour, Antoine; Kang, Sohyeong; Bolger-Munro, Madison; Scurll, Joshua M.; Priatel, John J.; Schweigler, Patrick; Melkko, Samu; Gold, Michael R.; Viner, Rosa I.; Régnier, Catherine H.; Turvey, Stuart E.; Overall, Christopher M.

2015-01-01

Antigen receptor signalling activates the canonical NF-κB pathway via the CARD11/BCL10/MALT1 (CBM) signalosome involving key, yet ill-defined roles for linear ubiquitination. The paracaspase MALT1 cleaves and removes negative checkpoint proteins, amplifying lymphocyte responses in NF-κB activation and in B-cell lymphoma subtypes. To identify new human MALT1 substrates, we compare B cells from the only known living MALT1mut/mut patient with healthy MALT1+/mut family members using 10-plex Tandem Mass Tag TAILS N-terminal peptide proteomics. We identify HOIL1 of the linear ubiquitin chain assembly complex as a novel MALT1 substrate. We show linear ubiquitination at B-cell receptor microclusters and signalosomes. Late in the NF-κB activation cycle HOIL1 cleavage transiently reduces linear ubiquitination, including of NEMO and RIP1, dampening NF-κB activation and preventing reactivation. By regulating linear ubiquitination, MALT1 is both a positive and negative pleiotropic regulator of the human canonical NF-κB pathway—first promoting activation via the CBM—then triggering HOIL1-dependent negative-feedback termination, preventing reactivation. PMID:26525107

Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

PubMed Central

Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

2015-01-01

Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

Lifeguard inhibition of Fas-mediated apoptosis: A possible mechanism for explaining the cisplatin resistance of triple-negative breast cancer cells.

PubMed

Radin, Daniel; Lippa, Arnold; Patel, Parth; Leonardi, Donna

2016-02-01

Triple-negative breast cancer does not express estrogen receptor-α, progesterone or the HER2 receptor making hormone or antibody therapy ineffective. Cisplatin may initiate p73-dependent apoptosis in p53 mutant cell lines through Fas trimerization and Caspase-8 activation and Bax up regulation and subsequent Caspase-9 activation. The triple-negative breast cancer, MDA-MB-231, overexpresses the protein Lifeguard, which inhibits Fas-mediated apoptosis by inhibiting Caspase-8 activation after Fas trimerization. The relationship between Fas, Lifeguard and cisplatin is investigated by down regulating Lifeguard via shRNA. Results demonstrate that cisplatin's efficacy increases when Lifeguard is down regulated. Lifeguard Knockdown MDA-MB-231 continue to decrease in cell viability from 24 to 48h after cisplatin treatment while no additional decrease in viability is observed in the Wild-Type MDA over the same period. Higher Caspase-8 activity in the Lifeguard knockdown MDA after cisplatin administration could explain the significant decrease in cell viability from 24 to 48h. This cell type is also more sensitive to Fas ligand-mediated reductions in cell viability, confirming Lifeguard's anti-apoptotic function through the Fas receptor. This research suggests that the efficacy of chemotherapy acting through the Fas pathway would increase if Lifeguard were not overexpressed to inhibit Fas-mediated apoptosis. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Human I-mfa domain proteins specifically interact with KSHV LANA and affect its regulation of Wnt signaling-dependent transcription

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusano, Shuichi, E-mail: skusano@m2.kufm.kagoshima-u.ac.jp; Eizuru, Yoshito

2010-06-04

Kaposi's sarcoma-associated herpes virus (KSHV)-encoded latency-associated nuclear antigen (LANA) protein has been reported to interact with glycogen synthase kinase 3{beta} (GSK-3{beta}) and to negatively regulate its activity, leading to stimulation of GSK-3{beta}-dependent {beta}-catenin degradation. We show here that the I-mfa domain proteins, HIC (human I-mfa domain-containing protein) and I-mfa (inhibitor of MyoD family a), interacted in vivo with LANA through their C-terminal I-mfa domains. This interaction affected the intracellular localization of HIC, inhibited the LANA-dependent transactivation of a {beta}-catenin-regulated reporter construct, and decreased the level of the LANA.GSK-3{beta} complex. These data reveal for the first time that I-mfa domain proteinsmore » interact with LANA and negatively regulate LANA-mediated activation of Wnt signaling-dependent transcription by inhibiting the formation of the LANA.GSK-3{beta} complex.« less

Neural correlates of emotional regulation while viewing films.

PubMed

Shimamura, Arthur P; Marian, Diane E; Haskins, Andrew L

2013-03-01

Negative and arousal-inducing film clips were used to assess the neural correlates of emotional expression and suppression. Compared to viewing neutral clips, both negative (disgusting) and arousal (action) clips activated primarily posterior regions in the parietal and occipital cortex when participants were instructed to express their emotions. When instructed to suppress their emotions while viewing negative clips, a broad frontoparietal network was activated that included lateral, medial, and orbital regions in the prefrontal cortex as well as lateral and medial regions of the posterior parietal cortex. The suppression of arousal clips also activated prefrontal and parietal regions, though not to the same extent as the suppression of negative clips. The findings demonstrate the potency of using movies to engage emotional processes and highlight a broad frontoparietal network that is engaged during the suppression of negative film clips.

FOREVER YOUNG FLOWER Negatively Regulates Ethylene Response DNA-Binding Factors by Activating an Ethylene-Responsive Factor to Control Arabidopsis Floral Organ Senescence and Abscission1

PubMed Central

Li, Pei-Fang; Lee, Yung-I; Yang, Chang-Hsien

2015-01-01

In this study of Arabidopsis (Arabidopsis thaliana), we investigated the relationship between FOREVER YOUNG FLOWER (FYF) and Ethylene Response DNA-binding Factors (EDFs) and functionally analyzed a key FYF target, an Ethylene-Responsive Factor (ERF), that controls flower senescence/abscission. Ectopic expression of EDF1/2/3/4 caused promotion of flower senescence/abscission and the activation of the senescence-associated genes. The presence of a repressor domain in EDFs and the enhancement of the promotion of senescence/abscission in EDF1/2/3/4+SRDX (converting EDFs to strong repressors by fusion with the ERF-associated amphiphilic repression motif repression domain SRDX) transgenic plants suggested that EDFs act as repressors. The significant reduction of β-glucuronidase (GUS) expression by 35S:FYF in EDF1/2/3/4:GUS plants indicates that EDF1/2/3/4 functions downstream of FYF in regulating flower senescence/abscission. In this study, we also characterized an ERF gene, FOREVER YOUNG FLOWER UP-REGULATING FACTOR1 (FUF1), which is up-regulated by FYF during flower development. Ectopic expression of FUF1 caused similar delayed flower senescence/abscission as seen in 35S:FYF plants. This phenotype was correlated with deficient abscission zone formation, ethylene insensitivity, and down-regulation of EDF1/2/3/4 and abscission-associated genes in 35S:FUF1 flowers. In contrast, significant promotion of flower senescence/abscission and up-regulation of EDF1/2/3/4 were observed in 35S:FUF1+SRDX transgenic dominant-negative plants, in which FUF1 is converted to a potent repressor by fusion to an SRDX-suppressing motif. Thus, FUF1 acts as an activator in suppressing EDF1/2/3/4 function and senescence/abscission of the flowers. Our results reveal that FYF regulates flower senescence/abscission by negatively regulating EDF1/2/3/4, which is the downstream gene in the ethylene response, by activating FUF1 in Arabidopsis. PMID:26063506

FOREVER YOUNG FLOWER Negatively Regulates Ethylene Response DNA-Binding Factors by Activating an Ethylene-Responsive Factor to Control Arabidopsis Floral Organ Senescence and Abscission.

PubMed

Chen, Wei-Han; Li, Pei-Fang; Chen, Ming-Kun; Lee, Yung-I; Yang, Chang-Hsien

2015-08-01

In this study of Arabidopsis (Arabidopsis thaliana), we investigated the relationship between FOREVER YOUNG FLOWER (FYF) and Ethylene Response DNA-binding Factors (EDFs) and functionally analyzed a key FYF target, an Ethylene-Responsive Factor (ERF), that controls flower senescence/abscission. Ectopic expression of EDF1/2/3/4 caused promotion of flower senescence/abscission and the activation of the senescence-associated genes. The presence of a repressor domain in EDFs and the enhancement of the promotion of senescence/abscission in EDF1/2/3/4+SRDX (converting EDFs to strong repressors by fusion with the ERF-associated amphiphilic repression motif repression domain SRDX) transgenic plants suggested that EDFs act as repressors. The significant reduction of β-glucuronidase (GUS) expression by 35S:FYF in EDF1/2/3/4:GUS plants indicates that EDF1/2/3/4 functions downstream of FYF in regulating flower senescence/abscission. In this study, we also characterized an ERF gene, FOREVER YOUNG FLOWER UP-REGULATING FACTOR1 (FUF1), which is up-regulated by FYF during flower development. Ectopic expression of FUF1 caused similar delayed flower senescence/abscission as seen in 35S:FYF plants. This phenotype was correlated with deficient abscission zone formation, ethylene insensitivity, and down-regulation of EDF1/2/3/4 and abscission-associated genes in 35S:FUF1 flowers. In contrast, significant promotion of flower senescence/abscission and up-regulation of EDF1/2/3/4 were observed in 35S:FUF1+SRDX transgenic dominant-negative plants, in which FUF1 is converted to a potent repressor by fusion to an SRDX-suppressing motif. Thus, FUF1 acts as an activator in suppressing EDF1/2/3/4 function and senescence/abscission of the flowers. Our results reveal that FYF regulates flower senescence/abscission by negatively regulating EDF1/2/3/4, which is the downstream gene in the ethylene response, by activating FUF1 in Arabidopsis. © 2015 American Society of Plant Biologists. All Rights Reserved.

The Wheat Mediator Subunit TaMED25 Interacts with the Transcription Factor TaEIL1 to Negatively Regulate Disease Resistance against Powdery Mildew.

PubMed

Liu, Jie; Zhang, Tianren; Jia, Jizeng; Sun, Jiaqiang

2016-03-01

Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici, is a major limitation for the production of bread wheat (Triticum aestivum). However, to date, the transcriptional regulation of bread wheat defense against powdery mildew remains largely unknown. Here, we report the function and molecular mechanism of the bread wheat Mediator subunit 25 (TaMED25) in regulating the bread wheat immune response signaling pathway. Three homoalleles of TaMED25 from bread wheat were identified and mapped to chromosomes 5A, 5B, and 5D, respectively. We show that knockdown of TaMED25 by barley stripe mosaic virus-induced gene silencing reduced bread wheat susceptibility to the powdery mildew fungus during the compatible plant-pathogen interaction. Moreover, our results indicate that MED25 may play a conserved role in regulating bread wheat and barley (Hordeum vulgare) susceptibility to powdery mildew. Similarly, bread wheat ETHYLENE INSENSITIVE3-LIKE1 (TaEIL1), an ortholog of Arabidopsis (Arabidopsis thaliana) ETHYLENE INSENSITIVE3, negatively regulates bread wheat resistance against powdery mildew. Using various approaches, we demonstrate that the conserved activator-interacting domain of TaMED25 interacts physically with the separate amino- and carboxyl-terminal regions of TaEIL1, contributing to the transcriptional activation activity of TaEIL1. Furthermore, we show that TaMED25 and TaEIL1 synergistically activate ETHYLENE RESPONSE FACTOR1 (TaERF1) transcription to modulate bread wheat basal disease resistance to B. graminis f. sp. tritici by repressing the expression of pathogenesis-related genes and deterring the accumulation of reactive oxygen species. Collectively, we identify the TaMED25-TaEIL1-TaERF1 signaling module as a negative regulator of bread wheat resistance to powdery mildew. © 2016 American Society of Plant Biologists. All Rights Reserved.

The Wheat Mediator Subunit TaMED25 Interacts with the Transcription Factor TaEIL1 to Negatively Regulate Disease Resistance against Powdery Mildew1

PubMed Central

Zhang, Tianren; Jia, Jizeng; Sun, Jiaqiang

2016-01-01

Powdery mildew, caused by the biotrophic fungal pathogen Blumeria graminis f. sp. tritici, is a major limitation for the production of bread wheat (Triticum aestivum). However, to date, the transcriptional regulation of bread wheat defense against powdery mildew remains largely unknown. Here, we report the function and molecular mechanism of the bread wheat Mediator subunit 25 (TaMED25) in regulating the bread wheat immune response signaling pathway. Three homoalleles of TaMED25 from bread wheat were identified and mapped to chromosomes 5A, 5B, and 5D, respectively. We show that knockdown of TaMED25 by barley stripe mosaic virus-induced gene silencing reduced bread wheat susceptibility to the powdery mildew fungus during the compatible plant-pathogen interaction. Moreover, our results indicate that MED25 may play a conserved role in regulating bread wheat and barley (Hordeum vulgare) susceptibility to powdery mildew. Similarly, bread wheat ETHYLENE INSENSITIVE3-LIKE1 (TaEIL1), an ortholog of Arabidopsis (Arabidopsis thaliana) ETHYLENE INSENSITIVE3, negatively regulates bread wheat resistance against powdery mildew. Using various approaches, we demonstrate that the conserved activator-interacting domain of TaMED25 interacts physically with the separate amino- and carboxyl-terminal regions of TaEIL1, contributing to the transcriptional activation activity of TaEIL1. Furthermore, we show that TaMED25 and TaEIL1 synergistically activate ETHYLENE RESPONSE FACTOR1 (TaERF1) transcription to modulate bread wheat basal disease resistance to B. graminis f. sp. tritici by repressing the expression of pathogenesis-related genes and deterring the accumulation of reactive oxygen species. Collectively, we identify the TaMED25-TaEIL1-TaERF1 signaling module as a negative regulator of bread wheat resistance to powdery mildew. PMID:26813794

DAX1 suppresses FXR transactivity as a novel co-repressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jin; Lu, Yan; Liu, Ruya

2011-09-09

Highlights: {yields} DAX1 is co-localized with FXR and interacts with FXR. {yields} DAX1 acts as a negative regulator of FXR. {yields} Three LXXLL motifs in the N-terminus of DAX1 were required. {yields} DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor familymore » due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1{alpha}. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.« less

A PLC-γ1 Feedback Pathway Regulates Lck Substrate Phosphorylation at the T-Cell Receptor and SLP-76 Complex.

PubMed

Belmont, Judson; Gu, Tao; Mudd, Ashley; Salomon, Arthur R

2017-08-04

Phospholipase C gamma 1 (PLC-γ1) occupies a critically important position in the T-cell signaling pathway. While its functions as a regulator of both Ca 2+ signaling and PKC-family kinases are well characterized, PLC-γ1's role in the regulation of early T-cell receptor signaling events is incompletely understood. Activation of the T-cell receptor leads to the formation of a signalosome complex between SLP-76, LAT, PLC-γ1, Itk, and Vav1. Recent studies have revealed the existence of both positive and negative feedback pathways from SLP-76 to the apical kinase in the pathway, Lck. To determine if PLC-γ1 contributes to the regulation of these feedback networks, we performed a quantitative phosphoproteomic analysis of PLC-γ1-deficient T cells. These data revealed a previously unappreciated role for PLC-γ1 in the positive regulation of Zap-70 and T-cell receptor tyrosine phosphorylation. Conversely, PLC-γ1 negatively regulated the phosphorylation of SLP-76-associated proteins, including previously established Lck substrate phosphorylation sites within this complex. While the positive and negative regulatory phosphorylation sites on Lck were largely unchanged, Tyr 192 phosphorylation was elevated in Jgamma1. The data supports a model wherein Lck's targeting, but not its kinase activity, is altered by PLC-γ1, possibly through Lck Tyr 192 phosphorylation and increased association of the kinase with protein scaffolds SLP-76 and TSAd.

Optomotor-blind negatively regulates Drosophila eye development by blocking Jak/STAT signaling.

PubMed

Tsai, Yu-Chen; Grimm, Stefan; Chao, Ju-Lan; Wang, Shih-Chin; Hofmeyer, Kerstin; Shen, Jie; Eichinger, Fred; Michalopoulou, Theoni; Yao, Chi-Kuang; Chang, Chih-Hsuan; Lin, Shih-Han; Sun, Y Henry; Pflugfelder, Gert O

2015-01-01

Organ formation requires a delicate balance of positive and negative regulators. In Drosophila eye development, wingless (wg) is expressed at the lateral margins of the eye disc and serves to block retinal development. The T-box gene optomotor-blind (omb) is expressed in a similar pattern and is regulated by Wg. Omb mediates part of Wg activity in blocking eye development. Omb exerts its function primarily by blocking cell proliferation. These effects occur predominantly in the ventral margin. Our results suggest that the primary effect of Omb is the blocking of Jak/STAT signaling by repressing transcription of upd which encodes the Jak receptor ligand Unpaired.

Selective Regulation of Maize Plasma Membrane Aquaporin Trafficking and Activity by the SNARE SYP121[W

PubMed Central

Besserer, Arnaud; Burnotte, Emeline; Bienert, Gerd Patrick; Chevalier, Adrien S.; Errachid, Abdelmounaim; Grefen, Christopher; Blatt, Michael R.; Chaumont, François

2012-01-01

Plasma membrane intrinsic proteins (PIPs) are aquaporins facilitating the diffusion of water through the cell membrane. We previously showed that the traffic of the maize (Zea mays) PIP2;5 to the plasma membrane is dependent on the endoplasmic reticulum diacidic export motif. Here, we report that the post-Golgi traffic and water channel activity of PIP2;5 are regulated by the SNARE (for soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) SYP121, a plasma membrane resident syntaxin involved in vesicle traffic, signaling, and regulation of K+ channels. We demonstrate that the expression of the dominant-negative SYP121-Sp2 fragment in maize mesophyll protoplasts or epidermal cells leads to a decrease in the delivery of PIP2;5 to the plasma membrane. Protoplast and oocyte swelling assays showed that PIP2;5 water channel activity is negatively affected by SYP121-Sp2. A combination of in vitro (copurification assays) and in vivo (bimolecular fluorescence complementation, Förster resonance energy transfer, and yeast split-ubiquitin) approaches allowed us to demonstrate that SYP121 and PIP2;5 physically interact. Together with previous data demonstrating the role of SYP121 in regulating K+ channel trafficking and activity, these results suggest that SYP121 SNARE contributes to the regulation of the cell osmotic homeostasis. PMID:22942383

Selective regulation of maize plasma membrane aquaporin trafficking and activity by the SNARE SYP121.

PubMed

Besserer, Arnaud; Burnotte, Emeline; Bienert, Gerd Patrick; Chevalier, Adrien S; Errachid, Abdelmounaim; Grefen, Christopher; Blatt, Michael R; Chaumont, François

2012-08-01

Plasma membrane intrinsic proteins (PIPs) are aquaporins facilitating the diffusion of water through the cell membrane. We previously showed that the traffic of the maize (Zea mays) PIP2;5 to the plasma membrane is dependent on the endoplasmic reticulum diacidic export motif. Here, we report that the post-Golgi traffic and water channel activity of PIP2;5 are regulated by the SNARE (for soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) SYP121, a plasma membrane resident syntaxin involved in vesicle traffic, signaling, and regulation of K(+) channels. We demonstrate that the expression of the dominant-negative SYP121-Sp2 fragment in maize mesophyll protoplasts or epidermal cells leads to a decrease in the delivery of PIP2;5 to the plasma membrane. Protoplast and oocyte swelling assays showed that PIP2;5 water channel activity is negatively affected by SYP121-Sp2. A combination of in vitro (copurification assays) and in vivo (bimolecular fluorescence complementation, Förster resonance energy transfer, and yeast split-ubiquitin) approaches allowed us to demonstrate that SYP121 and PIP2;5 physically interact. Together with previous data demonstrating the role of SYP121 in regulating K(+) channel trafficking and activity, these results suggest that SYP121 SNARE contributes to the regulation of the cell osmotic homeostasis.

Prefrontal mediation of emotion regulation in social anxiety disorder during laughter perception.

PubMed

Kreifelts, Benjamin; Brück, Carolin; Ethofer, Thomas; Ritter, Jan; Weigel, Lena; Erb, Michael; Wildgruber, Dirk

2017-02-01

Social anxiety disorder (SAD) is characterized by negatively biased perception of social cues and deficits in emotion regulation. While negatively biased perception is thought to maintain social anxiety, emotion regulation represents an ability necessary to overcome both biased perception and social anxiety. Here, we used laughter as a social threat in a functional magnetic resonance imaging (fMRI) study to identify cerebral mediators linking SAD with attention and interpretation biases and their modification through cognitive emotion regulation in the form of reappraisal. We found that reappraisal abolished the negative laughter interpretation bias in SAD and that this process was directly mediated through activation patterns of the left dorsolateral prefrontal cortex (DLPFC) serving as a cerebral pivot between biased social perception and its normalization through reappraisal. Connectivity analyses revealed reduced prefrontal control over threat-processing sensory cortices (here: the temporal voice area) during cognitive emotion regulation in SAD. Our results indicate a central role for the left DLPFC in SAD which might represent a valuable target for future research on interventions either aiming to directly modulate cognitive emotion regulation in SAD or to evaluate its potential as physiological marker for psychotherapeutic interventions relying on emotion regulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein Phosphotyrosine Phosphatase 1B (PTP1B) in Calpain-dependent Feedback Regulation of Vascular Endothelial Growth Factor Receptor (VEGFR2) in Endothelial Cells

PubMed Central

Zhang, Yixuan; Li, Qiang; Youn, Ji Youn; Cai, Hua

2017-01-01

The VEGF/VEGFR2/Akt/eNOS/NO pathway is essential to VEGF-induced angiogenesis. We have previously discovered a novel role of calpain in mediating VEGF-induced PI3K/AMPK/Akt/eNOS activation through Ezrin. Here, we sought to identify possible feedback regulation of VEGFR2 by calpain via its substrate protein phosphotyrosine phosphatase 1B (PTP1B), and the relevance of this pathway to VEGF-induced angiogenesis, especially in diabetic wound healing. Overexpression of PTP1B inhibited VEGF-induced VEGFR2 and Akt phosphorylation in bovine aortic endothelial cells, while PTP1B siRNA increased both, implicating negative regulation of VEGFR2 by PTP1B. Calpain inhibitor ALLN induced VEGFR2 activation, which can be completely blocked by PTP1B overexpression. Calpain activation induced by overexpression or Ca/A23187 resulted in PTP1B cleavage, which can be blocked by ALLN. Moreover, calpain activation inhibited VEGF-induced VEGFR2 phosphorylation, which can be restored by PTP1B siRNA. These data implicate calpain/PTP1B negative feedback regulation of VEGFR2, in addition to the primary signaling pathway of VEGF/VEGFR2/calpain/PI3K/AMPK/Akt/eNOS. We next examined a potential role of PTP1B in VEGF-induced angiogenesis. Endothelial cells transfected with PTP1B siRNA showed faster wound closure in response to VEGF. Aortic discs isolated from PTP1B siRNA-transfected mice also had augmented endothelial outgrowth. Importantly, PTP1B inhibition and/or calpain overexpression significantly accelerated wound healing in STZ-induced diabetic mice. In conclusion, our data for the first time demonstrate a calpain/PTP1B/VEGFR2 negative feedback loop in the regulation of VEGF-induced angiogenesis. Modulation of local PTP1B and/or calpain activities may prove beneficial in the treatment of impaired wound healing in diabetes. PMID:27872190

Exercise dependence score in patients with longstanding eating disorders and controls: the importance of affect regulation and physical activity intensity.

PubMed

Bratland-Sanda, Solfrid; Martinsen, Egil W; Rosenvinge, Jan H; Rø, Oyvind; Hoffart, Asle; Sundgot-Borgen, Jorunn

2011-01-01

To examine associations among exercise dependence score, amount of physical activity and eating disorder (ED) symptoms in patients with longstanding ED and non-clinical controls. Adult female inpatients (n = 59) and 53 age-matched controls participated in this cross sectional study. Assessments included the eating disorders examination, eating disorders inventory, exercise dependence scale, reasons for exercise inventory, and MTI Actigraph accelerometer. Positive associations were found among vigorous, not moderate, physical activity, exercise dependence score and ED symptoms in patients. In the controls, ED symptoms were negatively associated with vigorous physical activity and not correlated with exercise dependence score. Exercise for negative affect regulation, not weight/appearance, and amount of vigorous physical activity were explanatory variables for exercise dependence score in both groups. The positive associations among exercise dependence score, vigorous physical activity and ED symptoms need proper attention in the treatment of longstanding ED. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.

MAP Kinase-Mediated Negative Regulation of Symbiotic Nodule Formation in Medicago truncatula.

PubMed

Ryu, Hojin; Laffont, Carole; Frugier, Florian; Hwang, Ildoo

2017-01-01

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula . The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN . We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.

MAP Kinase-Mediated Negative Regulation of Symbiotic Nodule Formation in Medicago truncatula

PubMed Central

Ryu, Hojin; Laffont, Carole; Frugier, Florian; Hwang, Ildoo

2017-01-01

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors. PMID:28152300

The role of body-related self-conscious emotions in motivating women's physical activity.

PubMed

Sabiston, Catherine M; Brunet, Jennifer; Kowalski, Kent C; Wilson, Philip M; Mack, Diane E; Crocker, Peter R E

2010-08-01

The purpose of this study was to test a model where body-related self-conscious emotions of shame, guilt, and pride were associated with physical activity regulations and behavior. Adult women (N = 389; M age = 29.82, SD = 15.20 years) completed a questionnaire assessing body-related pride, shame, and guilt, motivational regulations, and leisure-time physical activity. The hypothesized measurement and structural models were deemed adequate, as was a revised model examining shame-free guilt and guilt-free shame. In the revised structural model, body-related pride was positively significantly related to identified and intrinsic regulations. Body-related shame-free guilt was significantly associated with external, introjected, and identified regulations. Body-related guilt-free shame was significantly positively related to external and introjected regulation, and negatively associated with intrinsic regulation. Identified and intrinsic regulations were significantly positively related to physical activity (R2 = .62). These findings highlight the importance of targeting and understanding the realm of body-related self-conscious emotions and the associated links to regulations and physical activity behavior.

GlnR-Mediated Regulation of ectABCD Transcription Expands the Role of the GlnR Regulon to Osmotic Stress Management

PubMed Central

Shao, ZhiHui; Deng, WanXin; Li, ShiYuan; He, JuanMei; Ren, ShuangXi; Huang, WeiRen; Lu, YinHua; Zhao, GuoPing

2015-01-01

ABSTRACT Ectoine and hydroxyectoine are excellent compatible solutes for bacteria to deal with environmental osmotic stress and temperature damages. The biosynthesis cluster of ectoine and hydroxyectoine is widespread among microorganisms, and its expression is activated by high salinity and temperature changes. So far, little is known about the mechanism of the regulation of the transcription of ect genes and only two MarR family regulators (EctR1 in methylobacteria and the EctR1-related regulator CosR in Vibrio cholerae) have been found to negatively regulate the expression of ect genes. Here, we characterize GlnR, the global regulator for nitrogen metabolism in actinomycetes, as a negative regulator for the transcription of ectoine/hydroxyectoine biosynthetic genes (ect operon) in Streptomyces coelicolor. The physiological role of this transcriptional repression by GlnR is proposed to protect the intracellular glutamate pool, which acts as a key nitrogen donor for both the nitrogen metabolism and the ectoine/hydroxyectoine biosynthesis. IMPORTANCE High salinity is deleterious, and cells must evolve sophisticated mechanisms to cope with this osmotic stress. Although production of ectoine and hydroxyectoine is one of the most frequently adopted strategies, the in-depth mechanism of regulation of their biosynthesis is less understood. So far, only two MarR family negative regulators, EctR1 and CosR, have been identified in methylobacteria and Vibrio, respectively. Here, our work demonstrates that GlnR, the global regulator for nitrogen metabolism, is a negative transcriptional regulator for ect genes in Streptomyces coelicolor. Moreover, a close relationship is found between nitrogen metabolism and osmotic resistance, and GlnR-mediated regulation of ect transcription is proposed to protect the intracellular glutamate pool. Meanwhile, the work reveals the multiple roles of GlnR in bacterial physiology. PMID:26170409

AP-1-mediated chromatin looping regulates ZEB2 transcription: new insights into TNFα-induced epithelial-mesenchymal transition in triple-negative breast cancer.

PubMed

Qiao, Yichun; Shiue, Chiou-Nan; Zhu, Jian; Zhuang, Ting; Jonsson, Philip; Wright, Anthony P H; Zhao, Chunyan; Dahlman-Wright, Karin

2015-04-10

The molecular determinants of malignant cell behaviour in triple-negative breast cancer (TNBC) are poorly understood. Recent studies have shown that regulators of epithelial-mesenchymal transition (EMT) are potential therapeutic targets for TNBC. In this study, we demonstrate that the inflammatory cytokine TNFα induces EMT in TNBC cells via activation of AP-1 signaling and subsequently induces expression of the EMT regulator ZEB2. We also show that TNFα activates both the PI3K/Akt and MAPK/ERK pathways, which act upstream of AP-1. We further investigated in detail AP-1 regulation of ZEB2 expression. We show that two ZEB2 transcripts derived from distinct promoters are both expressed in breast cancer cell lines and breast tumor samples. Using the chromosome conformation capture assay, we demonstrate that AP-1, when activated by TNFα, binds to a site in promoter 1b of the ZEB2 gene where it regulates the expression of both promoter 1b and 1a, the latter via mediating long range chromatin interactions. Overall, this work provides a plausible mechanism for inflammation-induced metastatic potential in TNBC, involving a novel regulatory mechanism governing ZEB2 isoform expression.

AP-1-mediated chromatin looping regulates ZEB2 transcription: new insights into TNFα-induced epithelial–mesenchymal transition in triple-negative breast cancer

PubMed Central

Qiao, Yichun; Shiue, Chiou-Nan; Zhu, Jian; Zhuang, Ting; Jonsson, Philip; Wright, Anthony P.H.; Zhao, Chunyan; Dahlman-Wright, Karin

2015-01-01

The molecular determinants of malignant cell behaviour in triple-negative breast cancer (TNBC) are poorly understood. Recent studies have shown that regulators of epithelial-mesenchymal transition (EMT) are potential therapeutic targets for TNBC. In this study, we demonstrate that the inflammatory cytokine TNFα induces EMT in TNBC cells via activation of AP-1 signaling and subsequently induces expression of the EMT regulator ZEB2. We also show that TNFα activates both the PI3K/Akt and MAPK/ERK pathways, which act upstream of AP-1. We further investigated in detail AP-1 regulation of ZEB2 expression. We show that two ZEB2 transcripts derived from distinct promoters are both expressed in breast cancer cell lines and breast tumor samples. Using the chromosome conformation capture assay, we demonstrate that AP-1, when activated by TNFα, binds to a site in promoter 1b of the ZEB2 gene where it regulates the expression of both promoter 1b and 1a, the latter via mediating long range chromatin interactions. Overall, this work provides a plausible mechanism for inflammation-induced metastatic potential in TNBC, involving a novel regulatory mechanism governing ZEB2 isoform expression. PMID:25762639

Transport systems of Ventricaria ventricosa: asymmetry of the hyper- and hypotonic regulation mechanisms.

PubMed

Bisson, M A; Beilby, M J

2008-01-01

Hyper- and hypotonic stresses elicit apparently symmetrical responses in the alga Ventricaria. With hypertonic stress, membrane potential difference (PD) between the vacuole and the external medium becomes more positive, conductance at positive PDs (Gmpos) increases and KCl is actively taken up to increase turgor. With hypotonic stress, the membrane PD becomes more negative, conductance at negative PDs (Gmneg) increases and KCl is lost to decrease turgor. We used inhibitors that affect active transport to determine whether agents that inhibit the K(+) pump and hypertonic regulation also inhibit hypotonic regulatory responses. Cells whose turgor pressure was held low by the pressure probe (turgor-clamped) exhibited the same response as cells challenged by hyperosmotic medium, although the response was maintained longer than in osmotically challenged cells, which regulate turgor. The role of active K(+) transport was confirmed by the effects of decreased light, dichlorophenyldimethyl urea and diethylstilbestrol, which induced a uniformly low conductance (quiet state). Cells clamped to high turgor exhibited the same response as cells challenged by hypo-osmotic medium, but the response was similarly transient, making effects of inhibitors hard to determine. Unlike clamped cells, cells challenged by hypo-osmotic medium responded to inhibitors with rapid, transient, negative-going PDs, with decreased Gmneg and increased Gmpos (linearized I-V), achieving the quiet state as PD recovered. These changes are different from those exerted on the pump state, indicating that different transport systems are responsible for turgor regulation in the two cases.

Activation of Extracellular Signal-Regulated Kinase in the Anterior Cingulate Cortex Contributes to the Induction and Expression of Affective Pain

PubMed Central

Cao, Hong; Gao, Yong-Jing; Ren, Wen-Hua; Li, Ting-Ting; Duan, Kai-Zheng; Cui, Yi-Hui; Cao, Xiao-Hua; Zhao, Zhi-Qi; Ji, Ru-Rong; Zhang, Yu-Qiu

2009-01-01

The anterior cingulate cortex (ACC) is implicated in the affective response to noxious stimuli. However, little is known about the molecular mechanisms involved. The present study demonstrated that extracellular signal-regulated kinase (ERK) activation in the ACC plays a crucial role in pain-related negative emotion. Intraplantar formalin injection produced a transient ERK activation in laminae V–VI and a persistent ERK activation in laminae II–III of the rostral ACC (rACC) bilaterally. Using formalin-induced conditioned place avoidance (F-CPA) in rats, which is believed to reflect the pain-related negative emotion, we found that blockade of ERK activation in the rACC with MEK inhibitors prevented the induction of F-CPA. Interestingly, this blockade did not affect formalin-induced two-phase spontaneous nociceptive responses and CPA acquisition induced by electric foot-shock or U69,593, an innocuous aversive agent. Upstream, NMDA receptor, adenylyl cyclase (AC) and PKA activators activated ERK in rACC slices. Consistently, intra-rACC microinjection of AC or PKA inhibitors prevented F-CPA induction. Downstream, phosphorylation of cAMP response element binding protein (CREB) was induced in the rACC by formalin injection and by NMDA, AC and PKA activators in brain slices, which was suppressed by MEK inhibitors. Furthermore, ERK also contributed to the expression of pain-related negative emotion. Thus, when rats were re-exposed to the conditioning context for retrieval of pain experience, ERK and CREB were re-activated in the rACC, and inhibiting ERK activation blocked the expression of F-CPA. All together, our results demonstrate that ERK activation in the rACC is required for the induction and expression of pain-related negative affect. PMID:19279268

Emotion regulation strategies mediate the associations of positive and negative affect to upper extremity physical function.

PubMed

Talaei-Khoei, Mojtaba; Nemati-Rezvani, Hora; Fischerauer, Stefan F; Ring, David; Chen, Neal; Vranceanu, Ana-Maria

2017-05-01

The Gross process model of emotion regulation holds that emotion-eliciting situations (e.g. musculoskeletal illness) can be strategically regulated to determine the final emotional and behavioral response. Also, there is some evidence that innate emotional traits may predispose an individual to a particular regulating coping style. We enrolled 107 patients with upper extremity musculoskeletal illness in this cross-sectional study. They completed self-report measures of positive and negative affect, emotion regulation strategies (cognitive reappraisal and expressive suppression), upper extremity physical function, pain intensity, and demographics. We used Preacher and Hayes' bootstrapping approach to process analysis to infer the direct effect of positive and negative affect on physical function as well as their indirect effects through activation of emotion regulation strategies. Negative affect was associated with decreased physical function. The association was partly mediated by expressive suppression (b (SE)=-.10 (.05), 95% BCa CI [-.21, -.02]). Positive affect was associated with increased physical function. Cognitive reappraisal partially mediated this association (b (SE)=.11 (.05), 95% BCa CI [.03, .24]). After controlling for pain intensity, the ratio of the mediated effect to total effect grew even larger in controlled model comparing to uncontrolled model (33% vs. 26% for expressive suppression and 32% vs. 30% for cognitive reappraisal). The relationships between affect, emotion regulation strategies and physical function appear to be more dependent on the emotional response to an orthopedic condition rather than the intensity of the nociceptive stimulation of the pain. Findings support integration of emotion regulation training in skill-based psychotherapy in this population to mitigate the effect of negative affect and enhance the influence of positive affect on physical function. Copyright © 2017 Elsevier Inc. All rights reserved.

Cultural differences and similarities in beliefs, practices, and neural mechanisms of emotion regulation.

PubMed

Qu, Yang; Telzer, Eva H

2017-01-01

The current research examined whether culture shapes the beliefs, practices, and neural basis of emotion regulation. Twenty-nine American and Chinese participants reported their implicit theory of emotion and frequency of reappraisal use. They also underwent an fMRI scan while completing an emotion regulation task. Chinese (vs. American) participants reported more frequent use of reappraisal, which was mediated by their higher incremental theory of emotion (i.e., believing that emotion is changeable through effort). Although there were some cultural similarities in neural activation during emotion regulation, Chinese participants showed less ventrolateral prefrontal cortex (VLPFC) activation than American participants when regulating negative emotions. Lower VLPFC activation was associated with higher incremental theory of emotion and more frequent use of cognitive reappraisal. Findings suggest that culture may shape how individuals perceive and engage in emotion regulation, and ultimately, the neural mechanisms underlying emotion regulation. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

β-Catenin activity in the dermal papilla of the hair follicle regulates pigment-type switching

PubMed Central

Enshell-Seijffers, David; Lindon, Catherine; Wu, Eleanor; Taketo, Makoto M.; Morgan, Bruce A.

2010-01-01

The switch between black and yellow pigment is mediated by the interaction between Melanocortin receptor 1 (Mc1r) and its antagonist Agouti, but the genetic and developmental mechanisms that modify this interaction to obtain different coat color in distinct environments are poorly understood. Here, the role of Wnt/β-catenin signaling in the regulation of pigment-type switching was studied. Loss and gain of function of β-catenin in the dermal papilla (DP) of the hair follicle results in yellow and black animals, respectively. β-Catenin activity in the DP suppresses Agouti expression and activates Corin, a negative regulator of Agouti activity. In addition, β-catenin activity in the DP regulates melanocyte activity by a mechanism that is independent of both Agouti and Corin. The coordinate and inverse regulation of Agouti and Corin renders pelage pigmentation sensitive to changes in β-catenin activity in the DP that do not alter pelage structure. As a result, the signals that specify two biologically distinct quantitative traits are partially uncoupled despite their common regulation by the β-catenin pathway in the same cells. PMID:21098273

Negative feedback regulation of Homer 1a on norepinephrine-dependent cardiac hypertrophy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiarello, Carmelina; Bortoloso, Elena; Carpi, Andrea

2013-07-15

Homers are scaffolding proteins that modulate diverse cell functions being able to assemble signalling complexes. In this study, the presence, sub-cellular distribution and function of Homer 1 was investigated. Homer 1a and Homer 1b/c are constitutively expressed in cardiac muscle of both mouse and rat and in HL-1 cells, a cardiac cell line. As judged by confocal immunofluorescence microscopy, Homer 1a displays sarcomeric and peri-nuclear localization. In cardiomyocytes and cultured HL-1 cells, the hypertrophic agonist norepinephrine (NE) induces α{sub 1}-adrenergic specific Homer 1a over-expression, with a two-to-three-fold increase within 1 h, and no up-regulation of Homer 1b/c, as judged bymore » Western blot and qPCR. In HL-1 cells, plasmid-driven over-expression of Homer 1a partially antagonizes activation of ERK phosphorylation and ANF up-regulation, two well-established, early markers of hypertrophy. At the morphometric level, NE-induced increase of cell size is likewise and partially counteracted by exogenous Homer 1a. Under the same experimental conditions, Homer 1b/c does not have any effect on ANF up-regulation nor on cell hypertrophy. Thus, Homer 1a up-regulation is associated to early stages of cardiac hypertrophy and appears to play a negative feedback regulation on molecular transducers of hypertrophy. -- Highlights: • Homer 1a is constitutively expressed in cardiac tissue. • In HL-1 cells, norepinephrine activates signaling pathways leading to hypertrophy. • Homer 1a up-regulation is an early event of norepinephrine-induced hypertrophy. • Homer 1a plays a negative feedback regulation modulating pathological hypertrophy. • Over-expression of Homer 1a per se does not induce hypertrophy.« less

Relations among school students' self-determined motivation, perceived enjoyment, effort, and physical activity behaviors.

PubMed

Zhang, Tao

2009-12-01

Guided by the self-determination theory, the purpose of this study was to examine the predictive strength of self-determined motivation toward motivational outcomes (perceived enjoyment, perceived effort, physical activity behaviors) for 286 middle school students in physical education. Analyses indicated that intrinsic motivation, identified regulation, and introjected regulation were positively related to students' enjoyment, perceived effort, and physical activity, whereas amotivation was negatively associated with students' enjoyment and perceived effort. The findings highlighted the importance of higher self-determined motivation (intrinsic motivation and identified regulation) in students' perceived enjoyment, effort, and physical activity behaviors. This study supports the use of self-determination theory to investigate students' motivational outcomes in school physical education.

Phosphorylation acts positively and negatively to regulate MRTF-A subcellular localisation and activity

PubMed Central

Panayiotou, Richard; Miralles, Francesc; Pawlowski, Rafal; Diring, Jessica; Flynn, Helen R; Skehel, Mark; Treisman, Richard

2016-01-01

The myocardin-related transcription factors (MRTF-A and MRTF-B) regulate cytoskeletal genes through their partner transcription factor SRF. The MRTFs bind G-actin, and signal-regulated changes in cellular G-actin concentration control their nuclear accumulation. The MRTFs also undergo Rho- and ERK-dependent phosphorylation, but the function of MRTF phosphorylation, and the elements and signals involved in MRTF-A nuclear export are largely unexplored. We show that Rho-dependent MRTF-A phosphorylation reflects relief from an inhibitory function of nuclear actin. We map multiple sites of serum-induced phosphorylation, most of which are S/T-P motifs and show that S/T-P phosphorylation is required for transcriptional activation. ERK-mediated S98 phosphorylation inhibits assembly of G-actin complexes on the MRTF-A regulatory RPEL domain, promoting nuclear import. In contrast, S33 phosphorylation potentiates the activity of an autonomous Crm1-dependent N-terminal NES, which cooperates with five other NES elements to exclude MRTF-A from the nucleus. Phosphorylation thus plays positive and negative roles in the regulation of MRTF-A. DOI: http://dx.doi.org/10.7554/eLife.15460.001 PMID:27304076

The PPAR{gamma} coding region and its role in visceral obesity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boon Yin, Khoo; Institute for Research in Molecular Medicine; Najimudin, Nazalan

Peroxisome proliferator-activated receptor gamma (PPAR{gamma}) is a ligand activated transcription factor, plays many essential roles of biological function in higher organisms. The PPAR{gamma} is mainly expressed in adipose tissue. It regulates the transcriptional activity of genes by binding with other transcription factor. The PPAR{gamma} coding region has been found to be closest to that of monkey in ours and other research groups. Thus, monkey is a more suitable animal model for future PPAR{gamma} studying, although mice and rat are frequently being used. The PPAR{gamma} is involved in regulating alterations of adipose tissue masses result from changes in mature adipocyte sizemore » and/or number through a complex interplay process called adipogenesis. However, the role of PPAR{gamma} in negatively regulating the process of adipogenesis remains unclear. This review may help we investigate the differential expression of key transcription factor in adipose tissue in response to visceral obesity-induced diet in vivo. The study may also provide valuable information to define a more appropriate physiological condition in adipogenesis which may help to prevent diseases cause by negative regulation of the transcription factors in adipose tissue.« less

Osteoblast differentiation and skeletal development are regulated by Mdm2–p53 signaling

PubMed Central

Lengner, Christopher J.; Steinman, Heather A.; Gagnon, James; Smith, Thomas W.; Henderson, Janet E.; Kream, Barbara E.; Stein, Gary S.; Lian, Jane B.; Jones, Stephen N.

2006-01-01

Mdm2 is required to negatively regulate p53 activity at the peri-implantation stage of early mouse development. However, the absolute requirement for Mdm2 throughout embryogenesis and in organogenesis is unknown. To explore Mdm2–p53 signaling in osteogenesis, Mdm2-conditional mice were bred with Col3.6-Cre–transgenic mice that express Cre recombinase in osteoblast lineage cells. Mdm2-conditional Col3.6-Cre mice die at birth and display multiple skeletal defects. Osteoblast progenitor cells deleted for Mdm2 have elevated p53 activity, reduced proliferation, reduced levels of the master osteoblast transcriptional regulator Runx2, and reduced differentiation. In contrast, p53-null osteoprogenitor cells have increased proliferation, increased expression of Runx2, increased osteoblast maturation, and increased tumorigenic potential, as mice specifically deleted for p53 in osteoblasts develop osteosarcomas. These results demonstrate that p53 plays a critical role in bone organogenesis and homeostasis by negatively regulating bone development and growth and by suppressing bone neoplasia and that Mdm2-mediated inhibition of p53 function is a prerequisite for Runx2 activation, osteoblast differentiation, and proper skeletal formation. PMID:16533949

Negative regulation of protein phosphatase 2Cbeta by ISG15 conjugation.

PubMed

Takeuchi, Tomoharu; Kobayashi, Takayasu; Tamura, Shinri; Yokosawa, Hideyoshi

2006-08-07

ISG15, an interferon-upregulated ubiquitin-like protein, is covalently conjugated to various cellular proteins (ISGylation). In this study, we found that protein phosphatase 2Cbeta (PP2Cbeta), which functions in the nuclear factor kappaB (NF-kappaB) pathway via dephosphorylation of TGF-beta-activated kinase, was ISGylated, and analysis by NF-kappaB luciferase reporter assay revealed that PP2Cbeta activity was suppressed by co-expression of ISG15, UBE1L, and UbcH8. We determined the ISGylation sites of PP2Cbeta and constructed its ISGylation-resistant mutant. In contrast to the wild type, this mutant suppressed the NF-kappaB pathway even in the presence of ISG15, UBE1L, and UbcH8. Thus, we propose that ISGylation negatively regulates PP2Cbeta activity.

Association of stigma resistance with emotion regulation - functional magnetic resonance imaging and neuropsychological findings.

PubMed

Raij, Tuukka T; Korkeila, Jyrki; Joutsenniemi, Kaisla; Saarni, Samuli I; Riekki, Tapani J J

2014-04-01

[corrected] Personal characteristics contribute to whether negative attitudes in society are internalized as deteriorating self-stigma. Studies in healthy subjects suggest that resilience is associated with the regulation of amygdala activation by the medial prefrontal cortex (mPFC), but little is known about the factors that contribute to individual stigma resistance in psychiatric patients. We assessed stigma (by measuring association strengths between social inferiority and schizophrenia by an implicit association test) in 20 patients with schizophrenia and in 16 age- and sex-matched healthy control subjects. The brain activation strengths were measured by functional magnetic resonance imaging during evaluation of schizophrenia-related statements and of control statements. Association strengths between social inferiority and schizophrenia were inversely related to the strength of the activation of the rostro-ventral mPFC. This inverse correlation survived adjustment for global functioning, depression symptom scores, and insight. Activation of the rostro-ventral mPFC was negatively correlated with activation of the amygdala. The association strengths between social inferiority and schizophrenia correlated with the compromised performance in a Stroop task, which is a measure of cognitive regulation. Our findings suggest that individual stigma resistance is associated with emotion regulation. These findings may help to understand better stigma resistance and thereby aid the development of patient interventions that add to the public anti-stigma work in reducing devastating effects of stigma. © 2014.

Phosphoinositide regulation of TRPV1 revisited

PubMed Central

Rohacs, Tibor

2015-01-01

The heat- and capsaicin-sensitive Transient Receptor Potential Vanilloid 1 ion channel (TRPV1) is regulated by plasma membrane phosphoinositides. The effects of these lipids on this channel have been controversial. Recent articles re-ignited the debate and also offered resolution to place some of the data in a coherent picture. This review summarizes the literature on this topic and provides a detailed and critical discussion on the experimental evidence for the various effects of phosphatidylinositol 4,5-bisphosphayte [PI(4,5)P2 or PIP2] on TRPV1. We conclude that PI(4,5)P2 and potentially its precursor PI(4)P are positive cofactors for TRPV1, acting via direct interaction with the channel, and their depletion by Ca2+-induced activation of phospholipase Cδ isoforms (PLCδ) limits channel activity during capsaicin-induced desensitization. Other negatively charged lipids at higher concentrations can also support channel activity, which may explain some controversies in the literature. PI(4,5)P2 also partially inhibits channel activity in some experimental settings, and relief from this inhibition upon PLCβ activation may contribute to sensitization. The negative effect of PI(4,5)P2 is more controversial and its mechanism is less well understood. Other TRP channels from the TRPV and TRPC families may also undergo similar dual regulation by phosphoinositides, thus the complexity of TRPV1 regulation is not unique to this channel. PMID:25754030

Deliberate real-time mood regulation in adulthood: the importance of age, fixation and attentional functioning.

PubMed

Noh, Soo Rim; Lohani, Monika; Isaacowitz, Derek M

2011-09-01

While previous research has linked executive attention to emotion regulation, the current study investigated the role of attentional alerting (i.e., efficient use of external warning cues) on younger (N=39) and older (N=44) adults' use of gaze to regulate their mood in real time. Participants viewed highly arousing unpleasant images while reporting their mood and were instructed to deliberately manage how they felt and to minimise the effect of those stimuli on their mood. Fixations toward the most negative areas of the images were recorded with eye tracking. We examined whether looking less at the most negative regions, compared to each individual's own tendency, was a beneficial mood regulatory strategy and how it interacted with age and alerting ability. High alerting older adults, who rely more on external cues to guide their attention, experienced a smaller decline in mood over time by activating a less-negative-looking approach (compared to their own average tendency), effectively looking away from the most negative areas of the images. More negative gaze patterns predicted better mood for younger adults, though this effect decreased over time. Alerting did not moderate gaze-mood links in younger adults. Successful mood regulation may thus depend on particular combinations of age, fixation, and attention.

Deliberate Real-time Mood Regulation in Adulthood: The Importance of Age, Fixation and Attentional Functioning

PubMed Central

Noh, Soo Rim; Lohani, Monika; Isaacowitz, Derek M.

2011-01-01

While previous research has linked executive attention to emotion regulation, the current study investigated the role of attentional alerting (i.e., efficient use of external warning cues) on younger (N = 39) and older (N = 44) adults’ use of gaze to regulate their mood in real time. Participants viewed highly arousing unpleasant images while reporting their mood and were instructed to deliberately manage how they felt and to minimize the effect of those stimuli on their mood. Fixations toward the most negative areas of the images were recorded with eye tracking. We examined whether looking less at the most negative regions, compared to each individual’s own tendency, was a beneficial mood regulatory strategy and how it interacted with age and alerting ability. High alerting older adults, who rely more on external cues to guide their attention, experienced a smaller decline in mood over time by activating a less-negative-looking approach (compared to their own average tendency), effectively looking away from the most negative areas of the images. More negative gaze patterns predicted better mood for younger adults, though this effect decreased over time. Alerting did not moderate gaze-mood links in younger adults. Successful mood regulation may thus depend on particular combinations of age, fixation, and attention. PMID:21432641

Differential regulation of Smad3 and of the type II transforming growth factor-β receptor in mitosis: implications for signaling.

PubMed

Hirschhorn, Tal; Barizilay, Lior; Smorodinsky, Nechama I; Ehrlich, Marcelo

2012-01-01

The response to transforming growth factor-β (TGF-β) depends on cellular context. This context is changed in mitosis through selective inhibition of vesicle trafficking, reduction in cell volume and the activation of mitotic kinases. We hypothesized that these alterations in cell context may induce a differential regulation of Smads and TGF-β receptors. We tested this hypothesis in mesenchymal-like ovarian cancer cells, arrested (or not) in mitosis with 2-methoxyestradiol (2ME2). In mitosis, without TGF-β stimulation, Smad3 was phosphorylated at the C-terminus and linker regions and localized to the mitotic spindle. Phosphorylated Smad3 interacted with the negative regulators of Smad signaling, Smurf2 and Ski, and failed to induce a transcriptional response. Moreover, in cells arrested in mitosis, Smad3 levels were progressively reduced. These phosphorylations and reduction in the levels of Smad3 depended on ERK activation and Mps1 kinase activity, and were abrogated by increasing the volume of cells arrested in mitosis with hypotonic medium. Furthermore, an Mps1-dependent phosphorylation of GFP-Smad3 was also observed upon its over-expression in interphase cells, suggesting a mechanism of negative regulation which counters increases in Smad3 concentration. Arrest in mitosis also induced a block in the clathrin-mediated endocytosis of the type II TGF-β receptor (TβRII). Moreover, following the stimulation of mitotic cells with TGF-β, the proteasome-mediated attenuation of TGF-β receptor activity, the degradation and clearance of TβRII from the plasma membrane, and the clearance of the TGF-β ligand from the medium were compromised, and the C-terminus phosphorylation of Smad3 was prolonged. We propose that the reduction in Smad3 levels, its linker phosphorylation, and its association with negative regulators (observed in mitosis prior to ligand stimulation) represent a signal attenuating mechanism. This mechanism is balanced by the retention of active TGF-β receptors at the plasma membrane. Together, both mechanisms allow for a regulated cellular response to TGF-β stimuli in mitosis.

Differential Regulation of Smad3 and of the Type II Transforming Growth Factor-β Receptor in Mitosis: Implications for Signaling

PubMed Central

Hirschhorn, Tal; Barizilay, Lior; Smorodinsky, Nechama I.; Ehrlich, Marcelo

2012-01-01

The response to transforming growth factor-β (TGF-β) depends on cellular context. This context is changed in mitosis through selective inhibition of vesicle trafficking, reduction in cell volume and the activation of mitotic kinases. We hypothesized that these alterations in cell context may induce a differential regulation of Smads and TGF-β receptors. We tested this hypothesis in mesenchymal-like ovarian cancer cells, arrested (or not) in mitosis with 2-methoxyestradiol (2ME2). In mitosis, without TGF-β stimulation, Smad3 was phosphorylated at the C-terminus and linker regions and localized to the mitotic spindle. Phosphorylated Smad3 interacted with the negative regulators of Smad signaling, Smurf2 and Ski, and failed to induce a transcriptional response. Moreover, in cells arrested in mitosis, Smad3 levels were progressively reduced. These phosphorylations and reduction in the levels of Smad3 depended on ERK activation and Mps1 kinase activity, and were abrogated by increasing the volume of cells arrested in mitosis with hypotonic medium. Furthermore, an Mps1-dependent phosphorylation of GFP-Smad3 was also observed upon its over-expression in interphase cells, suggesting a mechanism of negative regulation which counters increases in Smad3 concentration. Arrest in mitosis also induced a block in the clathrin-mediated endocytosis of the type II TGF-β receptor (TβRII). Moreover, following the stimulation of mitotic cells with TGF-β, the proteasome-mediated attenuation of TGF-β receptor activity, the degradation and clearance of TβRII from the plasma membrane, and the clearance of the TGF-β ligand from the medium were compromised, and the C-terminus phosphorylation of Smad3 was prolonged. We propose that the reduction in Smad3 levels, its linker phosphorylation, and its association with negative regulators (observed in mitosis prior to ligand stimulation) represent a signal attenuating mechanism. This mechanism is balanced by the retention of active TGF-β receptors at the plasma membrane. Together, both mechanisms allow for a regulated cellular response to TGF-β stimuli in mitosis. PMID:22927969

Thyroid hormone negatively regulates CDX2 and SOAT2 mRNA expression via induction of miRNA-181d in hepatic cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yap, Chui Sun; Sinha, Rohit Anthony; Ota, Sho

2013-11-01

Highlights: •Thyroid hormone induces miR-181d expression in human hepatic cells and mouse livers. •Thyroid hormone downregulates CDX2 and SOAT2 (or ACAT2) via miR-181d. •miR-181d reduces cholesterol output from human hepatic cells. -- Abstract: Thyroid hormones (THs) regulate transcription of many metabolic genes in the liver through its nuclear receptors (TRs). Although the molecular mechanisms for positive regulation of hepatic genes by TH are well understood, much less is known about TH-mediated negative regulation. Recently, several nuclear hormone receptors were shown to downregulate gene expression via miRNAs. To further examine the potential role of miRNAs in TH-mediated negative regulation, we usedmore » a miRNA microarray to identify miRNAs that were directly regulated by TH in a human hepatic cell line. In our screen, we discovered that miRNA-181d is a novel hepatic miRNA that was regulated by TH in hepatic cell culture and in vivo. Furthermore, we identified and characterized two novel TH-regulated target genes that were downstream of miR-181d signaling: caudal type homeobox 2 (CDX2) and sterol O-acyltransferase 2 (SOAT2 or ACAT2). CDX2, a known positive regulator of hepatocyte differentiation, was regulated by miR-181d and directly activated SOAT2 gene expression. Since SOAT2 is an enzyme that generates cholesteryl esters that are packaged into lipoproteins, our results suggest miR-181d plays a significant role in the negative regulation of key metabolic genes by TH in the liver.« less

A Role for APETALA1/FRUITFULL Transcription Factors in Tomato Leaf Development[C][W

PubMed Central

Burko, Yogev; Shleizer-Burko, Sharona; Yanai, Osnat; Shwartz, Ido; Zelnik, Iris Daphne; Jacob-Hirsch, Jasmine; Kela, Itai; Eshed-Williams, Leor; Ori, Naomi

2013-01-01

Flexible maturation rates underlie part of the diversity of leaf shape, and tomato (Solanum lycopersicum) leaves are compound due to prolonged organogenic activity of the leaf margin. The CINCINNATA -TEOSINTE BRANCHED1, CYCLOIDEA, PCF (CIN-TCP) transcription factor LANCEOLATE (LA) restricts this organogenic activity and promotes maturation. Here, we show that tomato APETALA1/FRUITFULL (AP1/FUL) MADS box genes are involved in tomato leaf development and are repressed by LA. AP1/FUL expression is correlated negatively with LA activity and positively with the organogenic activity of the leaf margin. LA binds to the promoters of the AP1/FUL genes MBP20 and TM4. Overexpression of MBP20 suppressed the simple-leaf phenotype resulting from upregulation of LA activity or from downregulation of class I knotted like homeobox (KNOXI) activity. Overexpression of a dominant-negative form of MBP20 led to leaf simplification and partly suppressed the increased leaf complexity of plants with reduced LA activity or increased KNOXI activity. Tomato plants overexpressing miR319, a negative regulator of several CIN-TCP genes including LA, flower with fewer leaves via an SFT-dependent pathway, suggesting that miR319-sensitive CIN-TCPs delay flowering in tomato. These results identify a role for AP1/FUL genes in vegetative development and show that leaf and plant maturation are regulated via partially independent mechanisms. PMID:23771895

A role for APETALA1/fruitfull transcription factors in tomato leaf development.

PubMed

Burko, Yogev; Shleizer-Burko, Sharona; Yanai, Osnat; Shwartz, Ido; Zelnik, Iris Daphne; Jacob-Hirsch, Jasmine; Kela, Itai; Eshed-Williams, Leor; Ori, Naomi

2013-06-01

Flexible maturation rates underlie part of the diversity of leaf shape, and tomato (Solanum lycopersicum) leaves are compound due to prolonged organogenic activity of the leaf margin. The CINCINNATA-teosinte branched1, cycloidea, PCF (CIN-TCP) transcription factor lanceolate (LA) restricts this organogenic activity and promotes maturation. Here, we show that tomato APETALA1/fruitfull (AP1/FUL) MADS box genes are involved in tomato leaf development and are repressed by LA. AP1/FUL expression is correlated negatively with LA activity and positively with the organogenic activity of the leaf margin. LA binds to the promoters of the AP1/FUL genes MBP20 and TM4. Overexpression of MBP20 suppressed the simple-leaf phenotype resulting from upregulation of LA activity or from downregulation of class I knotted like homeobox (KNOXI) activity. Overexpression of a dominant-negative form of MBP20 led to leaf simplification and partly suppressed the increased leaf complexity of plants with reduced LA activity or increased KNOXI activity. Tomato plants overexpressing miR319, a negative regulator of several CIN-TCP genes including LA, flower with fewer leaves via an SFT-dependent pathway, suggesting that miR319-sensitive CIN-TCPs delay flowering in tomato. These results identify a role for AP1/FUL genes in vegetative development and show that leaf and plant maturation are regulated via partially independent mechanisms.

The C-terminal domain of Nrf1 negatively regulates the full-length CNC-bZIP factor and its shorter isoform LCR-F1/Nrf1β; both are also inhibited by the small dominant-negative Nrf1γ/δ isoforms that down-regulate ARE-battery gene expression.

PubMed

Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

2014-01-01

The C-terminal domain (CTD, aa 686-741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ.

Allelic Dependent Expression of an Activating Fc receptor on B cells Enhances Humoral Immune Responses

PubMed Central

Li, Xinrui; Wu, Jianming; Ptacek, Travis; Redden, David T; Brown, Elizabeth E; Alarcón, Graciela S; Ramsey-Goldman, Rosalind; Petri, Michelle A; Reveille, John D.; Kaslow, Richard A; Kimberly, Robert P; Edberg, Jeffrey C

2014-01-01

B cells are pivotal regulators of acquired immune responses and recent work in both experimental murine models and humans has demonstrated that subtle changes in the regulation of B cell function can significantly alter immunological responses. The balance of negative and positive signals in maintaining an appropriate B cell activation threshold is critical in B lymphocyte immune tolerance and autoreactivity. FcγRIIb (CD32B), the only recognized Fcγ receptor on B cells, provides IgG-mediated negative modulation through a tyrosine-based inhibition motif which down-regulates B cell receptor initiated signaling. These properties make FcγRIIb a promising target for antibody-based therapy. Here we report the discovery of allele-dependent expression of the activating FcγRIIc on B cells. Identical to FcγRIIb in the extracellular domain, FcγRIIc has a tyrosine-based activation motif in its cytoplasmic domain. In both human B cells and in B cells from mice transgenic for human FcγRIIc, FcγRIIc expression counterbalances the negative feedback of FcγRIIb and enhances humoral responses to immunization in mice and to BioThrax® vaccination in a human Anthrax vaccine trial. Moreover, the FCGR2C-ORF allele is associated with the risk of development of autoimmunity in humans. FcγRIIc expression on B cells challenges the prevailing paradigm of uni-directional negative feedback by IgG immune complexes via the inhibitory FcγRIIb, is a previously unrecognized determinant in human antibody/autoantibody responses, and opens the opportunity for more precise personalized use of B cell targeted antibody-based therapy. PMID:24353158

GDSL LIPASE1 Modulates Plant Immunity through Feedback Regulation of Ethylene Signaling1[W

PubMed Central

Kim, Hye Gi; Kwon, Sun Jae; Jang, Young Jin; Nam, Myung Hee; Chung, Joo Hee; Na, Yun-Cheol; Guo, Hongwei; Park, Ohkmae K.

2013-01-01

Ethylene is a key signal in the regulation of plant defense responses. It is required for the expression and function of GDSL LIPASE1 (GLIP1) in Arabidopsis (Arabidopsis thaliana), which plays an important role in plant immunity. Here, we explore molecular mechanisms underlying the relationship between GLIP1 and ethylene signaling by an epistatic analysis of ethylene response mutants and GLIP1-overexpressing (35S:GLIP1) plants. We show that GLIP1 expression is regulated by ethylene signaling components and, further, that GLIP1 expression or application of petiole exudates from 35S:GLIP1 plants affects ethylene signaling both positively and negatively, leading to ETHYLENE RESPONSE FACTOR1 activation and ETHYLENE INSENSITIVE3 (EIN3) down-regulation, respectively. Additionally, 35S:GLIP1 plants or their exudates increase the expression of the salicylic acid biosynthesis gene SALICYLIC ACID INDUCTION-DEFICIENT2, known to be inhibited by EIN3 and EIN3-LIKE1. These results suggest that GLIP1 regulates plant immunity through positive and negative feedback regulation of ethylene signaling, and this is mediated by its activity to accumulate a systemic signal(s) in the phloem. We propose a model explaining how GLIP1 regulates the fine-tuning of ethylene signaling and ethylene-salicylic acid cross talk. PMID:24170202

An Integrated Process Model of Stereotype Threat Effects on Performance

PubMed Central

Johns, Michael; Forbes, Chad

2008-01-01

Research showing that activation of negative stereotypes can impair the performance of stigmatized individuals on a wide variety of tasks has proliferated. However, a complete understanding of the processes underlying these stereotype threat effects on behavior is still lacking. The authors examine stereotype threat in the context of research on stress arousal, vigilance, working memory, and self-regulation to develop a process model of how negative stereotypes impair performance on cognitive and social tasks that require controlled processing, as well as sensorimotor tasks that require automatic processing. The authors argue that stereotype threat disrupts performance via 3 distinct, yet interrelated, mechanisms: (a) a physiological stress response that directly impairs prefrontal processing, (b) a tendency to actively monitor performance, and (c) efforts to suppress negative thoughts and emotions in the service of self-regulation. These mechanisms combine to consume executive resources needed to perform well on cognitive and social tasks. The active monitoring mechanism disrupts performance on sensorimotor tasks directly. Empirical evidence for these assertions is reviewed, and implications for interventions designed to alleviate stereotype threat are discussed. PMID:18426293

MicroRNA-146 inhibits thrombin-induced NF-κB activation and subsequent inflammatory responses in human retinal endothelial cells.

PubMed

Cowan, Colleen; Muraleedharan, Chithra K; O'Donnell, James J; Singh, Pawan K; Lum, Hazel; Kumar, Ashok; Xu, Shunbin

2014-07-01

Nuclear factor-κB (NF-κB), a key regulator of immune and inflammatory responses, plays important roles in diabetes-induced microvascular complications including diabetic retinopathy (DR). Thrombin activates NF-κB through protease-activated receptor (PAR)-1, a member of the G-protein-coupled receptor (GPCR) superfamily, and contributes to DR. The current study is to uncover the roles of microRNA (miRNA) in thrombin-induced NF-κB activation and retinal endothelial functions. Target prediction was performed using the TargetScan algorithm. Predicted target was experimentally validated by luciferase reporter assays. Human retinal endothelial cells (HRECs) were transfected with miRNA mimics or antimiRs and treated with thrombin. Expression levels of miR-146 and related protein-coding genes were analyzed by quantitative (q)RT-PCR. Functional changes of HRECs were analyzed by leukocyte adhesion assays. We identified that caspase-recruitment domain (CARD)-containing protein 10 (CARD10), an essential scaffold/adaptor protein of GPCR-mediated NF-κB activation pathway, is a direct target of miR-146. Thrombin treatment resulted in NF-κB-dependent upregulation of miR-146 in HRECs; while transfection of miR-146 mimics resulted in significant downregulation of CARD10 and prevented thrombin-induced NF-κB activation, suggest that a negative feedback regulation of miR-146 on thrombin-induced NF-κB through targeting CARD10. Furthermore, overexpression of miR-146 prevented thrombin-induced increased leukocyte adhesion to HRECs. We uncovered a novel negative feedback regulatory mechanism on thrombin-induced GPCR-mediated NF-κB activation by miR-146. In combination with the negative feedback regulation of miR-146 on the IL-1R/toll-like receptor (TLR)-mediated NF-κB activation in RECs that we reported previously, our results underscore a pivotal, negative regulatory role of miR-146 on multiple NF-κB activation pathways and related inflammatory processes in DR. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Ser/Thr Phosphorylation Regulates the Fatty Acyl-AMP Ligase Activity of FadD32, an Essential Enzyme in Mycolic Acid Biosynthesis*

PubMed Central

Le, Nguyen-Hung; Molle, Virginie; Eynard, Nathalie; Miras, Mathieu; Stella, Alexandre; Bardou, Fabienne; Galandrin, Ségolène; Guillet, Valérie; André-Leroux, Gwenaëlle; Bellinzoni, Marco; Alzari, Pedro; Mourey, Lionel; Burlet-Schiltz, Odile; Daffé, Mamadou; Marrakchi, Hedia

2016-01-01

Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is a well known source of antituberculous drug targets. Among the promising new targets in the pathway, FadD32 is an essential enzyme required for the activation of the long meromycolic chain of mycolic acids and is essential for mycobacterial growth. Following the in-depth biochemical, biophysical, and structural characterization of FadD32, we investigated its putative regulation via post-translational modifications. Comparison of the fatty acyl-AMP ligase activity between phosphorylated and dephosphorylated FadD32 isoforms showed that the native protein is phosphorylated by serine/threonine protein kinases and that this phosphorylation induced a significant loss of activity. Mass spectrometry analysis of the native protein confirmed the post-translational modifications and identified Thr-552 as the phosphosite. Phosphoablative and phosphomimetic FadD32 mutant proteins confirmed both the position and the importance of the modification and its correlation with the negative regulation of FadD32 activity. Investigation of the mycolic acid condensation reaction catalyzed by Pks13, involving FadD32 as a partner, showed that FadD32 phosphorylation also impacts the condensation activity. Altogether, our results bring to light FadD32 phosphorylation by serine/threonine protein kinases and its correlation with the enzyme-negative regulation, thus shedding a new horizon on the mycolic acid biosynthesis modulation and possible inhibition strategies for this promising drug target. PMID:27590338

Optomotor-Blind Negatively Regulates Drosophila Eye Development by Blocking Jak/STAT Signaling

PubMed Central

Tsai, Yu-Chen; Grimm, Stefan; Chao, Ju-Lan; Wang, Shih-Chin; Hofmeyer, Kerstin; Shen, Jie; Eichinger, Fred; Michalopoulou, Theoni; Yao, Chi-Kuang; Chang, Chih-Hsuan; Lin, Shih-Han; Sun, Y. Henry; Pflugfelder, Gert O.

2015-01-01

Organ formation requires a delicate balance of positive and negative regulators. In Drosophila eye development, wingless (wg) is expressed at the lateral margins of the eye disc and serves to block retinal development. The T-box gene optomotor-blind (omb) is expressed in a similar pattern and is regulated by Wg. Omb mediates part of Wg activity in blocking eye development. Omb exerts its function primarily by blocking cell proliferation. These effects occur predominantly in the ventral margin. Our results suggest that the primary effect of Omb is the blocking of Jak/STAT signaling by repressing transcription of upd which encodes the Jak receptor ligand Unpaired. PMID:25781970

Negative Regulation of Type 2 Immunity

PubMed Central

de Kouchkovsky, Dimitri A.; Ghosh, Sourav; Rothlin, Carla V.

2017-01-01

Type 2 immunity encompasses the mechanisms through which the immune system responds to helminths and an array of environmental substances such as allergens. In the developing world, billions of individuals are chronically infected with endemic parasitic helminths. In comparison, in the industrialized world, millions of individuals suffer from dysregulated type 2 immunity, referred to clinically as atopic diseases including asthma, allergic rhinitis and atopic dermatitis. Thus, type 2 immunity must be carefully regulated to mount protective host response yet avoid inappropriate activation and immunopathology. In this review, we describe the keys players and connections at play in type 2 responses and focus on the emerging mechanisms involved in the negative regulation of type 2 immunity. PMID:28082101

NF-κB RelB Negatively Regulates Osteoblast Differentiation and Bone Formation

PubMed Central

Yao, Zhenqiang; Li, Yanyun; Yin, Xiaoxiang; Dong, Yufeng; Xing, Lianping; Boyce, Brendan F.

2013-01-01

RelA-mediated NF-κB canonical signaling promotes mesenchymal progenitor cell (MPC) proliferation, but inhibits differentiation of mature osteoblasts (OBs) and thus negatively regulates bone formation. Previous studies suggest that NF-κB RelB may also negatively regulate bone formation through non-canonical signaling, but they involved a complex knockout mouse model and the molecular mechanisms involved were not investigated. Here, we report that RelB−/− mice develop age-related increased trabecular bone mass associated with increased bone formation. RelB−/− bone marrow stromal cells expanded faster in vitro and have enhanced OB differentiation associated with increased expression of the osteoblastogenic transcription factor, Runx2. In addition, RelB directly targeted the Runx2 promoter to inhibit its activation. Importantly, RelB−/− bone-derived MPCs formed bone more rapidly than wild-type cells after they were injected into a murine tibial bone defect model. Our findings indicate that RelB negatively regulates bone mass as mice age and limits bone formation in healing bone defects, suggesting that inhibition of RelB could reduce age-related bone loss and enhance bone repair. PMID:24115294

Active pain coping is associated with the response in real-time fMRI neurofeedback during pain.

PubMed

Emmert, Kirsten; Breimhorst, Markus; Bauermann, Thomas; Birklein, Frank; Rebhorn, Cora; Van De Ville, Dimitri; Haller, Sven

2017-06-01

Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback is used as a tool to gain voluntary control of activity in various brain regions. Little emphasis has been put on the influence of cognitive and personality traits on neurofeedback efficacy and baseline activity. Here, we assessed the effect of individual pain coping on rt-fMRI neurofeedback during heat-induced pain. Twenty-eight healthy subjects completed the Coping Strategies Questionnaire (CSQ) prior to scanning. The first part of the fMRI experiment identified target regions using painful heat stimulation. Then, subjects were asked to down-regulate the pain target brain region during four neurofeedback runs with painful heat stimulation. Functional MRI analysis included correlation analysis between fMRI activation and pain ratings as well as CSQ ratings. At the behavioral level, the active pain coping (first principal component of CSQ) was correlated with pain ratings during neurofeedback. Concerning neuroimaging, pain sensitive regions were negatively correlated with pain coping. During neurofeedback, the pain coping was positively correlated with activation in the anterior cingulate cortex, prefrontal cortex, hippocampus and visual cortex. Thermode temperature was negatively correlated with anterior insula and dorsolateral prefrontal cortex activation. In conclusion, self-reported pain coping mechanisms and pain sensitivity are a source of variance during rt-fMRI neurofeedback possibly explaining variations in regulation success. In particular, active coping seems to be associated with successful pain regulation.

Suppression of Mediator is regulated by Cdk8-dependent Grr1 turnover of the Med3 coactivator.

PubMed

Gonzalez, Deyarina; Hamidi, Nurul; Del Sol, Ricardo; Benschop, Joris J; Nancy, Thomas; Li, Chao; Francis, Lewis; Tzouros, Manuel; Krijgsveld, Jeroen; Holstege, Frank C P; Conlan, R Steven

2014-02-18

Mediator, an evolutionary conserved large multisubunit protein complex with a central role in regulating RNA polymerase II-transcribed genes, serves as a molecular switchboard at the interface between DNA binding transcription factors and the general transcription machinery. Mediator subunits include the Cdk8 module, which has both positive and negative effects on activator-dependent transcription through the activity of the cyclin-dependent kinase Cdk8, and the tail module, which is required for positive and negative regulation of transcription, correct preinitiation complex formation in basal and activated transcription, and Mediator recruitment. Currently, the molecular mechanisms governing Mediator function remain largely undefined. Here we demonstrate an autoregulatory mechanism used by Mediator to repress transcription through the activity of distinct components of different modules. We show that the function of the tail module component Med3, which is required for transcription activation, is suppressed by the kinase activity of the Cdk8 module. Med3 interacts with, and is phosphorylated by, Cdk8; site-specific phosphorylation triggers interaction with and degradation by the Grr1 ubiquitin ligase, thereby preventing transcription activation. This active repression mechanism involving Grr1-dependent ubiquitination of Med3 offers a rationale for the substoichiometric levels of the tail module that are found in purified Mediator and the corresponding increase in tail components seen in cdk8 mutants.

The Growth Hormone Receptor: Mechanism of Receptor Activation, Cell Signaling, and Physiological Aspects

PubMed Central

Dehkhoda, Farhad; Lee, Christine M. M.; Medina, Johan; Brooks, Andrew J.

2018-01-01

The growth hormone receptor (GHR), although most well known for regulating growth, has many other important biological functions including regulating metabolism and controlling physiological processes related to the hepatobiliary, cardiovascular, renal, gastrointestinal, and reproductive systems. In addition, growth hormone signaling is an important regulator of aging and plays a significant role in cancer development. Growth hormone activates the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signaling pathway, and recent studies have provided a new understanding of the mechanism of JAK2 activation by growth hormone binding to its receptor. JAK2 activation is required for growth hormone-mediated activation of STAT1, STAT3, and STAT5, and the negative regulation of JAK–STAT signaling comprises an important step in the control of this signaling pathway. The GHR also activates the Src family kinase signaling pathway independent of JAK2. This review covers the molecular mechanisms of GHR activation and signal transduction as well as the physiological consequences of growth hormone signaling. PMID:29487568

Fisetin, a bioactive flavonol, attenuates allergic airway inflammation through negative regulation of NF-κB.

PubMed

Goh, Fera Y; Upton, Nadine; Guan, Shouping; Cheng, Chang; Shanmugam, Muthu K; Sethi, Gautam; Leung, Bernard P; Wong, W S Fred

2012-03-15

Persistent activation of nuclear factor-κB (NF-κB) has been associated with the development of asthma. Fisetin (3,7,3',4'-tetrahydroxyflavone), a naturally occurring bioactive flavonol, has been shown to inhibit NF-κB activity. We hypothesized that fisetin may attenuate allergic asthma via negative regulation of the NF-κB activity. Female BALB/c mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Fisetin dose-dependently inhibited ovalbumin-induced increases in total cell count, eosinophil count, and IL-4, IL-5 and IL-13 levels recovered in bronchoalveolar lavage fluid. It attenuated ovalbumin-induced lung tissue eosinophilia and airway mucus production, mRNA expression of adhesion molecules, chitinase, IL-17, IL-33, Muc5ac and inducible nitric oxide synthase in lung tissues, and airway hyperresponsiveness to methacholine. Fisetin blocked NF-κB subunit p65 nuclear translocation and DNA-binding activity in the nuclear extracts from lung tissues of ovalbumin-challenged mice. In normal human bronchial epithelial cells, fisetin repressed TNF-α-induced NF-κB-dependent reporter gene expression. Our findings implicate a potential therapeutic value of fisetin in the treatment of asthma through negative regulation of NF-κB pathway. Copyright © 2012 Elsevier B.V. All rights reserved.

Immunobiotic Lactobacillus jensenii Elicits Anti-Inflammatory Activity in Porcine Intestinal Epithelial Cells by Modulating Negative Regulators of the Toll-Like Receptor Signaling Pathway

PubMed Central

Shimazu, Tomoyuki; Villena, Julio; Tohno, Masanori; Fujie, Hitomi; Hosoya, Shoichi; Shimosato, Takeshi; Aso, Hisashi; Suda, Yoshihito; Kawai, Yasushi; Saito, Tadao; Makino, Seiya; Ikegami, Shuji; Itoh, Hiroyuki

2012-01-01

The effect of Lactobacillus jensenii TL2937 on the inflammatory immune response triggered by enterotoxigenic Escherichia coli (ETEC) and lipopolysaccharide (LPS) in a porcine intestinal epitheliocyte cell line (PIE cells) was evaluated. Challenges with ETEC or LPS elicited Toll-like receptor 4 (TLR4)-mediated inflammatory responses in cultured PIE cells, indicating that our cell line may be useful for studying inflammation in the guts of weaning piglets. In addition, we demonstrated that L. jensenii TL2937 attenuated the expression of proinflammatory cytokines and chemokines caused by ETEC or LPS challenge by downregulating TLR4-dependent nuclear factorκB (NF-κB) and mitogen-activated protein kinase (MAPK) activation. Furthermore, we demonstrated that L. jensenii TL2937 stimulation of PIE cells upregulated three negative regulators of TLRs: A20, Bcl-3, and MKP-1, deepening the understanding of an immunobiotic mechanism of action. L. jensenii TL2937-mediated induction of negative regulators of TLRs would have a substantial physiological impact on homeostasis in PIE cells, because excessive TLR inflammatory signaling would be downregulated. These results indicated that PIE cells can be used to study the mechanisms involved in the protective activity of immunobiotics against intestinal inflammatory damage and may provide useful information for the development of new immunologically functional feeds that help to prevent inflammatory intestinal disorders, including weaning-associated intestinal inflammation. PMID:22083706

GPR30 Activation Opposes Estrogen-Dependent Uterine Growth via Inhibition of Stromal ERK1/2 and Estrogen Receptor Alpha (ERα) Phosphorylation Signals

PubMed Central

Gao, Fei; Ma, Xinghong; Ostmann, Alicia B.

2011-01-01

Although estradiol-17β (E2)-regulated early and late phase uterine responses have been well defined, the molecular mechanisms linking the phases remain poorly understood. We have previously shown that E2-regulated early signals mediate cross talk with estrogen receptor (ER)-α to elicit uterine late growth responses. G protein-coupled receptor (GPR30) has been implicated in early nongenomic signaling mediated by E2, although its role in E2-dependent uterine biology is unclear. Using selective activation of GPR30 by G-1, we show here a new function of GPR30 in regulating early signaling events, including the inhibition of ERK1/2 and ERα (Ser118) phosphorylation signals and perturbation of growth regulation under the direction of E2 in the mouse uterus. We observed that GPR30 primarily localizes in the uterine epithelial cells, and its activation alters gene expression and mediates inhibition of ERK1/2 and ERα (Ser118) phosphorylation signals in the stromal compartment, suggesting a paracrine signaling is involved. Importantly, viral-driven manipulation of GPR30 or pharmacological inhibition of ERK1/2 activation effectively alters E2-dependent uterine growth responses. Overall, GPR30 is a negative regulator of ERα-dependent uterine growth in response to E2. Our work has uncovered a novel GPR30-regulated inhibitory event, which may be physiologically relevant in both normal and pathological situations to negatively balance ERα-dependent uterine growth regulatory functions induced by E2. PMID:21303939

DHEA Enhances Emotion Regulation Neurocircuits and Modulates Memory for Emotional Stimuli

PubMed Central

Sripada, Rebecca K; Marx, Christine E; King, Anthony P; Rajaram, Nirmala; Garfinkel, Sarah N; Abelson, James L; Liberzon, Israel

2013-01-01

Dehydroepiandrosterone (DHEA) is a neurosteroid with anxiolytic, antidepressant, and antiglucocorticoid properties. It is endogenously released in response to stress, and may reduce negative affect when administered exogenously. Although there have been multiple reports of DHEA's antidepressant and anxiolytic effects, no research to date has examined the neural pathways involved. In particular, brain imaging has not been used to link neurosteroid effects to emotion neurocircuitry. To investigate the brain basis of DHEA's impact on emotion modulation, patients were administered 400 mg of DHEA (N=14) or placebo (N=15) and underwent 3T fMRI while performing the shifted-attention emotion appraisal task (SEAT), a test of emotional processing and regulation. Compared with placebo, DHEA reduced activity in the amygdala and hippocampus, enhanced connectivity between the amygdala and hippocampus, and enhanced activity in the rACC. These activation changes were associated with reduced negative affect. DHEA reduced memory accuracy for emotional stimuli, and also reduced activity in regions associated with conjunctive memory encoding. These results demonstrate that DHEA reduces activity in regions associated with generation of negative emotion and enhances activity in regions linked to regulatory processes. Considering that activity in these regions is altered in mood and anxiety disorders, our results provide initial neuroimaging evidence that DHEA may be useful as a pharmacological intervention for these conditions and invite further investigation into the brain basis of neurosteroid emotion regulatory effects. PMID:23552182

The ribonucleoprotein Csr network.

PubMed

Seyll, Ethel; Van Melderen, Laurence

2013-11-08

Ribonucleoprotein complexes are essential regulatory components in bacteria. In this review, we focus on the carbon storage regulator (Csr) network, which is well conserved in the bacterial world. This regulatory network is composed of the CsrA master regulator, its targets and regulators. CsrA binds to mRNA targets and regulates translation either negatively or positively. Binding to small non-coding RNAs controls activity of this protein. Expression of these regulators is tightly regulated at the level of transcription and stability by various global regulators (RNAses, two-component systems, alarmone). We discuss the implications of these complex regulations in bacterial adaptation.

ChIP-seq reveals broad roles of SARD1 and CBP60g in regulating plant immunity.

PubMed

Sun, Tongjun; Zhang, Yaxi; Li, Yan; Zhang, Qian; Ding, Yuli; Zhang, Yuelin

2015-12-18

Recognition of pathogens by host plants leads to rapid transcriptional reprogramming and activation of defence responses. The expression of many defence regulators is induced in this process, but the mechanisms of how they are controlled transcriptionally are largely unknown. Here we use chromatin immunoprecipitation sequencing to show that the transcription factors SARD1 and CBP60g bind to the promoter regions of a large number of genes encoding key regulators of plant immunity. Among them are positive regulators of systemic immunity and signalling components for effector-triggered immunity and PAMP-triggered immunity, which is consistent with the critical roles of SARD1 and CBP60g in these processes. In addition, SARD1 and CBP60g target a number of genes encoding negative regulators of plant immunity, suggesting that they are also involved in negative feedback regulation of defence responses. Based on these findings we propose that SARD1 and CBP60g function as master regulators of plant immune responses.

In Sickness and in Health: The Co-Regulation of Inflammation and Social Behavior

PubMed Central

Eisenberger, Naomi I; Moieni, Mona; Inagaki, Tristen K; Muscatell, Keely A; Irwin, Michael R

2017-01-01

Although it has commonly been assumed that the immune system and the processes that govern social behavior are separate, non-communicating entities, research over the past several decades suggests otherwise. Considerable evidence now shows that inflammatory processes and social behavior are actually powerful regulators of one another. This review first summarizes evidence that inflammatory processes regulate social behavior, leading to characteristic changes that may help an individual navigate the social environment during times of sickness. Specifically, this review shows that inflammation: (1) increases threat-related neural sensitivity to negative social experiences (eg, rejection, negative social feedback), presumably to enhance sensitivity to threats to well-being or safety in order to avoid them and (2) enhances reward-related neural sensitivity to positive social experiences (eg, viewing close others and receiving positive social feedback), presumably to increase approach-related motivation towards others who might provide support and care during sickness. Next, this review summarizes evidence showing that social behavior also regulates aspects of inflammatory activity, preparing the body for situations in which wounding and infection may be more likely (social isolation). Here, we review research showing: (1) that exposure to social stressors increases proinflammatory activity, (2) that individuals who are more socially isolated (ie, lonely) show increased proinflammatory activity, and (3) that individuals who are more socially isolated show increased proinflammatory activity in response to an inflammatory challenge or social stressor. The implications of the co-regulation of inflammation and social behavior are discussed. PMID:27480575

Effect of aging on microRNAs and regulation of pathogen recognition receptors

PubMed Central

Olivieri, Fabiola; Procopio, Antonio Dormenico

2014-01-01

Immunosenescence is the multifactorial age-associated immune deteriorization that leads to increased susceptibility to infections and decreased responses to vaccines. Recent studies have shown a fundamental role for microRNAs (miRNAs) in regulating immune responses, and nearly all the miRNAs involved in immune regulation show modulation during aging. Aging-associated miRNAs are largely negative regulators of the immune innate response and target central nodes of aging-associated networks, in particular, NF-κB, the downstream effector of TLR signals that leads to induction of proinflammatory responses. Multiple miRNAs have been reported to share similar regulatory activity. Here we review miRNA regulation of human innate immune recognition in aging, including both activation and resolution of inflammation, critical issues in detection, and areas of active investigation into our understanding of immunosenescence. PMID:24769423

Orphan Nuclear Receptor Small Heterodimer Partner Negatively Regulates Growth Hormone-mediated Induction of Hepatic Gluconeogenesis through Inhibition of Signal Transducer and Activator of Transcription 5 (STAT5) Transactivation*

PubMed Central

Kim, Yong Deuk; Li, Tiangang; Ahn, Seung-Won; Kim, Don-Kyu; Lee, Ji-Min; Hwang, Seung-Lark; Kim, Yong-Hoon; Lee, Chul-Ho; Lee, In-Kyu; Chiang, John Y. L.; Choi, Hueng-Sik

2012-01-01

Growth hormone (GH) is a key metabolic regulator mediating glucose and lipid metabolism. Ataxia telangiectasia mutated (ATM) is a member of the phosphatidylinositol 3-kinase superfamily and regulates cell cycle progression. The orphan nuclear receptor small heterodimer partner (SHP: NR0B2) plays a pivotal role in regulating metabolic processes. Here, we studied the role of ATM on GH-dependent regulation of hepatic gluconeogenesis in the liver. GH induced phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase gene expression in primary hepatocytes. GH treatment and adenovirus-mediated STAT5 overexpression in hepatocytes increased glucose production, which was blocked by a JAK2 inhibitor, AG490, dominant negative STAT5, and STAT5 knockdown. We identified a STAT5 binding site on the PEPCK gene promoter using reporter assays and point mutation analysis. Up-regulation of SHP by metformin-mediated activation of the ATM-AMP-activated protein kinase pathway led to inhibition of GH-mediated induction of hepatic gluconeogenesis, which was abolished by an ATM inhibitor, KU-55933. Immunoprecipitation studies showed that SHP physically interacted with STAT5 and inhibited STAT5 recruitment on the PEPCK gene promoter. GH-induced hepatic gluconeogenesis was decreased by either metformin or Ad-SHP, whereas the inhibition by metformin was abolished by SHP knockdown. Finally, the increase of hepatic gluconeogenesis following GH treatment was significantly higher in the liver of SHP null mice compared with that of wild-type mice. Overall, our results suggest that the ATM-AMP-activated protein kinase-SHP network, as a novel mechanism for regulating hepatic glucose homeostasis via a GH-dependent pathway, may be a potential therapeutic target for insulin resistance. PMID:22977252

NLRP12 Suppresses Colon Inflammation and Tumorigenesis through the Negative Regulation of Non-canonical NF-κB Signaling and MAP Kinase Activation

PubMed Central

Allen, Irving C.; Wilson, Justin E.; Schneider, Monika; Lich, John D.; Roberts, Reid A.; Arthur, Janelle C.; Woodford, Rita-Marie T.; Davis, Beckley K.; Uronis, Joshua M.; Herfarth, Hans H.; Jobin, Christian; Rogers, Arlin B.; Ting, Jenny P.-Y.

2013-01-01

SUMMARY In vitro data suggest that a subgroup of NLR proteins, including NLRP12, inhibits the transcription factor NF-κB, although physiologic and disease-relevant evidence is largely missing. Dysregulated NF-κB activity is associated with colonic inflammation and cancer, and we found Nlrp12-/- mice were highly susceptible to colitis and colitis-associated colon cancer. Polyps isolated from Nlrp12-/- mice showed elevated non-canonical NF-κB activation and increased expression of target genes that were associated with cancer, including Cxcl13 and Cxcl12. NLRP12 negatively regulated ERK and AKT signaling pathways in affected tumor tissues. Both hematopoietic and nonhematopoietic-derived NLRP12 contributed to inflammation, but the latter dominantly contributed to tumorigenesis. The non-canonical NF-κB pathway was regulated upon degradation of TRAF3 and activation of NIK. NLRP12 interacted with both NIK and TRAF3, and Nlrp12-/- cells have constitutively elevated NIK, p100 processing to p52 and reduced TRAF3. Thus, NLRP12 is a checkpoint of noncanonical NF-κB, inflammation and tumorigenesis. PMID:22503542

Adaptor protein Lnk negatively regulates the mutant MPL, MPLW515L associated with myeloproliferative disorders

PubMed Central

Gueller, Saskia; Chumakova, Katya; Kawamata, Norihiko; Liu, Liqin; Koeffler, H. Phillip

2007-01-01

Recently, activating myeloproliferative leukemia virus oncogene (MPL) mutations, MPLW515L/K, were described in myeloproliferative disorder (MPD) patients. MPLW515L leads to activation of downstream signaling pathways and cytokine-independent proliferation in hematopoietic cells. The adaptor protein Lnk is a negative regulator of several cytokine receptors, including MPL. We show that overexpression of Lnk in Ba/F3-MPLW515L cells inhibits cytokine-independent growth, while suppression of Lnk in UT7-MPLW515L cells enhances proliferation. Lnk blocks the activation of Jak2, Stat3, Erk, and Akt in these cells. Furthermore, MPLW515L-expressing cells are more susceptible to Lnk inhibitory functions than their MPL wild-type (MPLWT)–expressing counterparts. Lnk associates with activated MPLWT and MPLW515L and colocalizes with the receptors at the plasma membrane. The SH2 domain of Lnk is essential for its binding and for its down-regulation of MPLWT and MPLW515L. Lnk itself is tyrosine-phosphorylated following thrombopoietin stimulation. Further elucidating the cellular pathways that attenuate MPLW515L will provide insight into the pathogenesis of MPD and could help develop specific therapeutic approaches. PMID:17693582

Adaptor protein Lnk negatively regulates the mutant MPL, MPLW515L associated with myeloproliferative disorders.

PubMed

Gery, Sigal; Gueller, Saskia; Chumakova, Katya; Kawamata, Norihiko; Liu, Liqin; Koeffler, H Phillip

2007-11-01

Recently, activating myeloproliferative leukemia virus oncogene (MPL) mutations, MPLW515L/K, were described in myeloproliferative disorder (MPD) patients. MPLW515L leads to activation of downstream signaling pathways and cytokine-independent proliferation in hematopoietic cells. The adaptor protein Lnk is a negative regulator of several cytokine receptors, including MPL. We show that overexpression of Lnk in Ba/F3-MPLW515L cells inhibits cytokine-independent growth, while suppression of Lnk in UT7-MPLW515L cells enhances proliferation. Lnk blocks the activation of Jak2, Stat3, Erk, and Akt in these cells. Furthermore, MPLW515L-expressing cells are more susceptible to Lnk inhibitory functions than their MPL wild-type (MPLWT)-expressing counterparts. Lnk associates with activated MPLWT and MPLW515L and colocalizes with the receptors at the plasma membrane. The SH2 domain of Lnk is essential for its binding and for its down-regulation of MPLWT and MPLW515L. Lnk itself is tyrosine-phosphorylated following thrombopoietin stimulation. Further elucidating the cellular pathways that attenuate MPLW515L will provide insight into the pathogenesis of MPD and could help develop specific therapeutic approaches.

Positive And Negative Feedback Loops Coupled By Common Transcription Activator And Repressor

NASA Astrophysics Data System (ADS)

Sielewiesiuk, Jan; Łopaciuk, Agata

2015-03-01

Dynamical systems consisting of two interlocked loops with negative and positive feedback have been studied using the linear analysis of stability and numerical solutions. Conditions for saddle-node bifurcation were formulated in a general form. Conditions for Hopf bifurcations were found in a few symmetrical cases. Auto-oscillations, when they exist, are generated by the negative feedback repressive loop. This loop determines the frequency and amplitude of oscillations. The positive feedback loop of activation slightly modifies the oscillations. Oscillations are possible when the difference between Hilll's coefficients of the repression and activation is sufficiently high. The highly cooperative activation loop with a fast turnover slows down or even makes the oscillations impossible. The system under consideration can constitute a component of epigenetic or enzymatic regulation network.

Protein phosphatase AP2C1 negatively regulates basal resistance and defense responses to Pseudomonas syringae.

PubMed

Shubchynskyy, Volodymyr; Boniecka, Justyna; Schweighofer, Alois; Simulis, Justinas; Kvederaviciute, Kotryna; Stumpe, Michael; Mauch, Felix; Balazadeh, Salma; Mueller-Roeber, Bernd; Boutrot, Freddy; Zipfel, Cyril; Meskiene, Irute

2017-02-01

Mitogen-activated protein kinases (MAPKs) mediate plant immune responses to pathogenic bacteria. However, less is known about the cell autonomous negative regulatory mechanism controlling basal plant immunity. We report the biological role of Arabidopsis thaliana MAPK phosphatase AP2C1 as a negative regulator of plant basal resistance and defense responses to Pseudomonas syringae. AP2C2, a closely related MAPK phosphatase, also negatively controls plant resistance. Loss of AP2C1 leads to enhanced pathogen-induced MAPK activities, increased callose deposition in response to pathogen-associated molecular patterns or to P. syringae pv. tomato (Pto) DC3000, and enhanced resistance to bacterial infection with Pto. We also reveal the impact of AP2C1 on the global transcriptional reprogramming of transcription factors during Pto infection. Importantly, ap2c1 plants show salicylic acid-independent transcriptional reprogramming of several defense genes and enhanced ethylene production in response to Pto. This study pinpoints the specificity of MAPK regulation by the different MAPK phosphatases AP2C1 and MKP1, which control the same MAPK substrates, nevertheless leading to different downstream events. We suggest that precise and specific control of defined MAPKs by MAPK phosphatases during plant challenge with pathogenic bacteria can strongly influence plant resistance. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

CRYPTOCHROME 2 and PHOTOTROPIN 2 regulate resistance protein mediated viral 2 defense by negatively regulating a E3 ubiquitin ligase

USDA-ARS?s Scientific Manuscript database

Light harvested by plants is essential for the survival of most life forms. This light perception ability requires the activities of proteins termed photoreceptors. We report a function for photoreceptors in mediating resistance (R) protein-derived plant defense. The blue-light photoreceptors, crypt...

Regulation of aldosterone secretion by mineralocorticoid receptor-mediated signaling.

PubMed

Chong, Cherish; Hamid, Anis; Yao, Tham; Garza, Amanda E; Pojoga, Luminita H; Adler, Gail K; Romero, Jose R; Williams, Gordon H

2017-03-01

We posit the existence of a paracrine/autocrine negative feedback loop, mediated by the mineralocorticoid receptor (MR), regulating aldosterone secretion. To assess this hypothesis, we asked whether altering MR activity in zona glomerulosa (ZG) cells affects aldosterone production. To this end, we studied ex vivo ZG cells isolated from male Wistar rats fed chow containing either high (1.6% Na + (HS)) or low (0.03% Na + (LS)) amount of sodium. Western blot analyses demonstrated that MR was present in both the ZG and zona fasciculata/zona reticularis (ZF/ZR/ZR). In ZG cells isolated from rats on LS chow, MR activation by fludrocortisone produced a 20% and 60% reduction in aldosterone secretion basally and in response to angiotensin II (ANGII) stimulation, respectively. Corticosterone secretion was increased in these cells suggesting that aldosterone synthase activity was being reduced by fludrocortisone. In contrast, canrenoic acid, an MR antagonist, enhanced aldosterone production by up to 30% both basally and in response to ANGII. Similar responses were observed in ZG cells from rats fed HS. Modulating glucocorticoid receptor (GR) activity did not alter aldosterone production by ZG cells; however, altering GR activity did modify corticosterone production from ZF/ZR/ZR cells both basally and in response to adrenocorticotropic hormone (ACTH). Additionally, activating the MR in ZF/ZR/ZR cells strikingly reduced corticosterone secretion. In summary, these data support the hypothesis that negative ultra-short feedback loops regulate adrenal steroidogenesis. In the ZG, aldosterone secretion is regulated by the MR, but not the GR, an effect that appears to be secondary to a change in aldosterone synthase activity. © 2017 Society for Endocrinology.

A Loss-of-Function Screen for Phosphatases that Regulate Neurite Outgrowth Identifies PTPN12 as a Negative Regulator of TrkB Tyrosine Phosphorylation

PubMed Central

Ambjørn, Malene; Dubreuil, Véronique; Miozzo, Federico; Nigon, Fabienne; Møller, Bente; Issazadeh-Navikas, Shohreh; Berg, Jacob; Lees, Michael; Sap, Jan

2013-01-01

Alterations in function of the neurotrophin BDNF are associated with neurodegeneration, cognitive decline, and psychiatric disorders. BDNF promotes axonal outgrowth and branching, regulates dendritic tree morphology and is important for axonal regeneration after injury, responses that largely result from activation of its tyrosine kinase receptor TrkB. Although intracellular neurotrophin (NT) signaling presumably reflects the combined action of kinases and phosphatases, little is known about the contributions of the latter to TrkB regulation. The issue is complicated by the fact that phosphatases belong to multiple independently evolved families, which are rarely studied together. We undertook a loss-of-function RNA-interference-based screen of virtually all known (254) human phosphatases to understand their function in BDNF/TrkB-mediated neurite outgrowth in differentiated SH-SY5Y cells. This approach identified phosphatases from diverse families, which either positively or negatively modulate BDNF-TrkB-mediated neurite outgrowth, and most of which have little or no previously established function related to NT signaling. “Classical” protein tyrosine phosphatases (PTPs) accounted for 13% of the candidate regulatory phosphatases. The top classical PTP identified as a negative regulator of BDNF-TrkB-mediated neurite outgrowth was PTPN12 (also called PTP-PEST). Validation and follow-up studies showed that endogenous PTPN12 antagonizes tyrosine phosphorylation of TrkB itself, and the downstream activation of ERK1/2. We also found PTPN12 to negatively regulate phosphorylation of p130cas and FAK, proteins with previously described functions related to cell motility and growth cone behavior. Our data provide the first comprehensive survey of phosphatase function in NT signaling and neurite outgrowth. They reveal the complexity of phosphatase control, with several evolutionarily unrelated phosphatase families cooperating to affect this biological response, and hence the relevance of considering all phosphatase families when mining for potentially druggable targets. PMID:23785422

Autonomous Motivation Predicts 7-Day Physical Activity in Hong Kong Students.

PubMed

Ha, Amy S; Ng, Johan Y Y

2015-07-01

Autonomous motivation predicts positive health behaviors such as physical activity. However, few studies have examined the relation between motivational regulations and objectively measured physical activity and sedentary behaviors. Thus, we investigated whether different motivational regulations (autonomous motivation, controlled motivation, and amotivation) predicted 7-day physical activity, sedentary behaviors, and health-related quality of life (HRQoL) of students. A total of 115 students (mean age = 11.6 years, 55.7% female) self-reported their motivational regulations and health-related quality of life. Physical activity and sedentary behaviors were measured using accelerometers for seven days. Using multilevel modeling, we found that autonomous motivation predicted higher levels of moderate-to-vigorous physical activity, less sedentary behaviors, and better HRQoL. Controlled motivation and amotivation each only negatively predicted one facet of HRQoL. Results suggested that autonomous motivation could be an important predictor of physical activity behaviors in Hong Kong students. Promotion of this form of motivational regulation may also increase HRQoL. © 2015 The International Association of Applied Psychology.

FRNK negatively regulates IL-4-mediated inflammation.

PubMed

Sharma, Ritu; Colarusso, Pina; Zhang, Hong; Stevens, Katarzyna M; Patel, Kamala D

2015-02-15

Focal adhesion kinase (FAK)-related nonkinase (PTK2 isoform 6 in humans, hereafter referred to as FRNK) is a cytoskeletal regulatory protein that has recently been shown to dampen lung fibrosis, yet its role in inflammation is unknown. Here, we show for the first time that expression of FRNK negatively regulates IL-4-mediated inflammation in a human model of eosinophil recruitment. Mechanistically, FRNK blocks eosinophil accumulation, firm adhesion and transmigration by preventing transcription and protein expression of VCAM-1 and CCL26. IL-4 activates STAT6 to induce VCAM-1 and CCL26 transcription. We now show that IL-4 also increases GATA6 to induce VCAM-1 expression. FRNK blocks IL-4-induced GATA6 transcription but has little effect on GATA6 protein expression and no effect on STAT6 activation. FRNK can block FAK or Pyk2 signaling and we, thus, downregulated these proteins using siRNA to determine whether signaling from either protein is involved in the regulation of VCAM-1 and CCL26. Knockdown of FAK, Pyk2 or both had no effect on VCAM-1 or CCL26 expression, which suggests that FRNK acts independently of FAK and Pyk2 signaling. Finally, we found that IL-4 induces the late expression of endogenous FRNK. In summary, FRNK represents a novel mechanism to negatively regulate IL-4-mediated inflammation. © 2015. Published by The Company of Biologists Ltd.

Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem1[OPEN

PubMed Central

Street, Ian H.; Aman, Sitwat; Zubo, Yan; Ramzan, Aleena; Wang, Xiaomin; Shakeel, Samina N.; Kieber, Joseph J.; Schaller, G. Eric

2015-01-01

The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem. PMID:26149574

Functional Divergence of Platelet Protein Kinase C (PKC) Isoforms in Thrombus Formation on Collagen*

PubMed Central

Gilio, Karen; Harper, Matthew T.; Cosemans, Judith M. E. M.; Konopatskaya, Olga; Munnix, Imke C. A.; Prinzen, Lenneke; Leitges, Michael; Liu, Qinghang; Molkentin, Jeffery D.; Heemskerk, Johan W. M.; Poole, Alastair W.

2010-01-01

Arterial thrombosis, a major cause of myocardial infarction and stroke, is initiated by activation of blood platelets by subendothelial collagen. The protein kinase C (PKC) family centrally regulates platelet activation, and it is becoming clear that the individual PKC isoforms play distinct roles, some of which oppose each other. Here, for the first time, we address all four of the major platelet-expressed PKC isoforms, determining their comparative roles in regulating platelet adhesion to collagen and their subsequent activation under physiological flow conditions. Using mouse gene knock-out and pharmacological approaches in human platelets, we show that collagen-dependent α-granule secretion and thrombus formation are mediated by the conventional PKC isoforms, PKCα and PKCβ, whereas the novel isoform, PKCθ, negatively regulates these events. PKCδ also negatively regulates thrombus formation but not α-granule secretion. In addition, we demonstrate for the first time that individual PKC isoforms differentially regulate platelet calcium signaling and exposure of phosphatidylserine under flow. Although platelet deficient in PKCα or PKCβ showed reduced calcium signaling and phosphatidylserine exposure, these responses were enhanced in the absence of PKCθ. In summary therefore, this direct comparison between individual subtypes of PKC, by standardized methodology under flow conditions, reveals that the four major PKCs expressed in platelets play distinct non-redundant roles, where conventional PKCs promote and novel PKCs inhibit thrombus formation on collagen. PMID:20479008

Functional divergence of platelet protein kinase C (PKC) isoforms in thrombus formation on collagen.

PubMed

Gilio, Karen; Harper, Matthew T; Cosemans, Judith M E M; Konopatskaya, Olga; Munnix, Imke C A; Prinzen, Lenneke; Leitges, Michael; Liu, Qinghang; Molkentin, Jeffery D; Heemskerk, Johan W M; Poole, Alastair W

2010-07-23

Arterial thrombosis, a major cause of myocardial infarction and stroke, is initiated by activation of blood platelets by subendothelial collagen. The protein kinase C (PKC) family centrally regulates platelet activation, and it is becoming clear that the individual PKC isoforms play distinct roles, some of which oppose each other. Here, for the first time, we address all four of the major platelet-expressed PKC isoforms, determining their comparative roles in regulating platelet adhesion to collagen and their subsequent activation under physiological flow conditions. Using mouse gene knock-out and pharmacological approaches in human platelets, we show that collagen-dependent alpha-granule secretion and thrombus formation are mediated by the conventional PKC isoforms, PKCalpha and PKCbeta, whereas the novel isoform, PKC, negatively regulates these events. PKCdelta also negatively regulates thrombus formation but not alpha-granule secretion. In addition, we demonstrate for the first time that individual PKC isoforms differentially regulate platelet calcium signaling and exposure of phosphatidylserine under flow. Although platelet deficient in PKCalpha or PKCbeta showed reduced calcium signaling and phosphatidylserine exposure, these responses were enhanced in the absence of PKC. In summary therefore, this direct comparison between individual subtypes of PKC, by standardized methodology under flow conditions, reveals that the four major PKCs expressed in platelets play distinct non-redundant roles, where conventional PKCs promote and novel PKCs inhibit thrombus formation on collagen.

Phosphorylation of Minichromosome Maintenance 3 (MCM3) by Checkpoint Kinase 1 (Chk1) Negatively Regulates DNA Replication and Checkpoint Activation.

PubMed

Han, Xiangzi; Mayca Pozo, Franklin; Wisotsky, Jacob N; Wang, Benlian; Jacobberger, James W; Zhang, Youwei

2015-05-08

Mechanisms controlling DNA replication and replication checkpoint are critical for the maintenance of genome stability and the prevention or treatment of human cancers. Checkpoint kinase 1 (Chk1) is a key effector protein kinase that regulates the DNA damage response and replication checkpoint. The heterohexameric minichromosome maintenance (MCM) complex is the core component of mammalian DNA helicase and has been implicated in replication checkpoint activation. Here we report that Chk1 phosphorylates the MCM3 subunit of the MCM complex at Ser-205 under normal growth conditions. Mutating the Ser-205 of MCM3 to Ala increased the length of DNA replication track and shortened the S phase duration, indicating that Ser-205 phosphorylation negatively controls normal DNA replication. Upon replicative stress treatment, the inhibitory phosphorylation of MCM3 at Ser-205 was reduced, and this reduction was accompanied with the generation of single strand DNA, the key platform for ataxia telangiectasia mutated and Rad3-related (ATR) activation. As a result, the replication checkpoint is activated. Together, these data provide significant insights into the regulation of both normal DNA replication and replication checkpoint activation through the novel phosphorylation of MCM3 by Chk1. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

HECT Domain-containing E3 Ubiquitin Ligase NEDD4L Negatively Regulates Wnt Signaling by Targeting Dishevelled for Proteasomal Degradation*

PubMed Central

Ding, Yi; Zhang, Yan; Xu, Chao; Tao, Qing-Hua; Chen, Ye-Guang

2013-01-01

Wnt signaling plays a pivotal role in embryogenesis and tissue homeostasis. Dishevelled (Dvl) is a central mediator for both Wnt/β-catenin and Wnt/planar cell polarity pathways. NEDD4L, an E3 ubiquitin ligase, has been shown to regulate ion channel activity, cell signaling, and cell polarity. Here, we report a novel role of NEDD4L in the regulation of Wnt signaling. NEDD4L induces Dvl2 polyubiquitination and targets Dvl2 for proteasomal degradation. Interestingly, the NEDD4L-mediated ubiquitination of Dvl2 is Lys-6, Lys-27, and Lys-29 linked but not typical Lys-48-linked ubiquitination. Consistent with the role of Dvl in both Wnt/β-catenin and Wnt/planar cell polarity signaling, NEDD4L regulates the cellular β-catenin level and Rac1, RhoA, and JNK activities. We have further identified a hierarchical regulation that Wnt5a induces JNK-mediated phosphorylation of NEDD4L, which in turn promotes its ability to degrade Dvl2. Finally, we show that NEDD4L inhibits Dvl2-induced axis duplication in Xenopus embryos. Our work thus demonstrates that NEDD4L is a negative feedback regulator of Wnt signaling. PMID:23396981

Free Market Ideology and Deregulation in Colorado’s Oilfields: Evidence for triple movement activism?

PubMed Central

Malin, Stephanie A.; Mayer, Adam; Shreeve, Kelly; Olson-Hazboun, Shawn K.; Adgate, John

2017-01-01

Unconventional oil and gas extraction (UOGE) has spurred an unprecedented boom in on-shore production in the U.S. Despite a surge in related research, a void exists regarding inquiries into policy outcomes and perceptions. To address this, support for federal regulatory exemptions for UOGE is examined using survey data collected in 2015 from two northern Colorado communities. Current regulatory exemptions for UOGE can be understood as components of broader societal processes of neoliberalization. Free market ideology increases public support for federal regulatory exemptions for UOGE. Perceived negative impacts do not necessarily drive people to support increased federal regulation. Utilizing neo-Polanyian theory, interaction between free market ideology and perceived negative impacts is explored. Free market ideology appears to moderate people’s views of regulation: increasing the effect of perceived negative impacts while simultaneously increasing support for deregulation. To conclude, the ways in which free market ideology might normalize the impacts of UOGE activity are discussed. PMID:29225425

Barrier role of actin filaments in regulated mucin secretion from airway goblet cells.

PubMed

Ehre, Camille; Rossi, Andrea H; Abdullah, Lubna H; De Pestel, Kathleen; Hill, Sandra; Olsen, John C; Davis, C William

2005-01-01

Airway goblet cells secrete mucin onto mucosal surfaces under the regulation of an apical, phospholipase C/G(q)-coupled P2Y(2) receptor. We tested whether cortical actin filaments negatively regulate exocytosis in goblet cells by forming a barrier between secretory granules and plasma membrane docking sites as postulated for other secretory cells. Immunostaining of human lung tissues and SPOC1 cells (an epithelial, mucin-secreting cell line) revealed an apical distribution of beta- and gamma-actin in ciliated and goblet cells. In goblet cells, actin appeared as a prominent subplasmalemmal sheet lying between granules and the apical membrane, and it disappeared from SPOC1 cells activated by purinergic agonist. Disruption of actin filaments with latrunculin A stimulated SPOC1 cell mucin secretion under basal and agonist-activated conditions, whereas stabilization with jasplakinolide or overexpression of beta- or gamma-actin conjugated to yellow fluorescent protein (YFP) inhibited secretion. Myristoylated alanine-rich C kinase substrate, a PKC-activated actin-plasma membrane tethering protein, was phosphorylated after agonist stimulation, suggesting a translocation to the cytosol. Scinderin (or adseverin), a Ca(2+)-activated actin filament severing and capping protein was cloned from human airway and SPOC1 cells, and synthetic peptides corresponding to its actin-binding domains inhibited mucin secretion. We conclude that actin filaments negatively regulate mucin secretion basally in airway goblet cells and are dynamically remodeled in agonist-stimulated cells to promote exocytosis.

Cut! that’s a wrap: regulating negative emotion by ending emotion-eliciting situations

PubMed Central

Vujovic, Lara; Opitz, Philipp C.; Birk, Jeffrey L.; Urry, Heather L.

2014-01-01

Little is known about the potentially powerful set of emotion regulation (ER) processes that target emotion-eliciting situations. We thus studied the decision to end emotion-eliciting situations in the laboratory. We hypothesized that people would try to end negative situations more frequently than neutral situations to regulate distress. In addition, motivated by the selection, optimization, and compensation with ER framework, we hypothesized that failed attempts to end the situation would prompt either (a) greater negative emotion or (b) compensatory use of a different ER process, attentional deployment (AD). Fifty-eight participants (18–26 years old, 67% women) viewed negative and neutral pictures and pressed a key whenever they wished to stop viewing them. After key press, the picture disappeared (“success”) or stayed (“failure”) on screen. To index emotion, we measured corrugator and electrodermal activity, heart rate, and self-reported arousal. To index overt AD, we measured eye gaze. As their reason for ending the situation, participants more frequently reported being upset by high- than low-arousal negative pictures; they more frequently reported being bored by low- than high-arousal neutral pictures. Nevertheless, participants’ negative emotional responding did not increase in the context of ER failure nor did they use overt AD as a compensatory ER strategy. We conclude that situation-targeted ER processes are used to regulate emotional responses to high-arousal negative and low-arousal neutral situations; ER processes other than overt AD may be used to compensate for ER failure in this context. PMID:24592251

Is There a Paradox of Aging: When the Negative Aging Stereotype Meets the Positivity Effect in Older Adults.

PubMed

Zhou, Liqing; Lu, Jia; Chen, Guopeng; Dong, Li; Yao, Yujia

2017-01-01

Background/Study Context: Socioemotional selectivity theory (SST) states that the positivity effect is a result of older adults' emotion regulation and that older adults derive more emotional satisfaction from prioritizing positive information processing. The authors explored whether the positivity effect appeared when the negative aging stereotype was activated in older adults and also whether the effect differed between mixed and unmixed valence conditions. Sixty younger (18-23 years of age) and 60 older (60-87 years of age) adults were randomly assigned to a control group and a priming group, in which the negative aging stereotype was activated. All the participants were asked to select 15 words that best described the elderly from a mixed-word list (positive and negative words were mixed together) and from an unmixed-word list (positive and negative words were separated). Older adults in the control group selected more positive words, whereas among younger adults, selection did not differ by valence in either the mixed- or unmixed-word list conditions. There were no differences between the positive and negative word choices of the younger and older adults in the priming group. We calculated the differences between the numbers of positive and negative words, and the differences in the older adults' word choices were larger than those among the younger adults; the differences were also larger in the control group than in the priming group. The positivity effect worked by choosing positive stimuli rather than avoiding negative stimuli. The role of emotion regulation in older adults was limited, and when the positivity effect faced the effect of the negative aging stereotype, the negative stereotype effect was dominant. Future research should explore the changes in the positivity effect in the face of a positive aging stereotype and what roles other factors (e.g., activation level of the stereotype, arousal level of affective words) might play.

Cognitive Emotion Regulation Strategies Associated With the DSM-5 Posttraumatic Stress Disorder Criteria.

PubMed

Kaczkurkin, Antonia N; Zang, Yinyin; Gay, Natalie G; Peterson, Alan L; Yarvis, Jeffrey S; Borah, Elisa V; Dondanville, Katherine A; Hembree, Elizabeth A; Litz, Brett T; Mintz, Jim; Young-McCaughan, Stacey; Foa, Edna B

2017-08-01

Maladaptive cognitive emotion regulation strategies have been proposed to contribute to the maintenance of posttraumatic stress disorder (PTSD). Prior work has focused on the relationship between these strategies and PTSD as a whole, rather than on how they are related to each PTSD symptom cluster. The purpose of the current study was to determine whether cognitive emotion regulation strategies are predictive of certain PTSD symptom clusters under the Diagnostic and Statistical Manual of Mental Disorders 5th ed. (DSM-5; American Psychiatric Association, 2013) criteria (intrusive thoughts, avoidance, negative alterations in cognitions and mood, and hyperarousal). Participants included 365 treatment-seeking, active-duty military personnel with PTSD. The negative alterations in cognitions and mood cluster were associated with dysfunctional cognitions: greater negative cognitions about the self, negative cognitions about the world, and self-blame, as well as catastrophizing (Rc2 = .519). The negative alterations in cognitions and mood cluster did not show a strong relationship with blaming others, possibly due to the complex nature of self- and other-blame in this primarily deployment-related PTSD sample. Finally, the intrusive thoughts cluster was associated with catastrophizing (Rc2 = .211), suggesting an association between frequent intrusive memories and excessively negative interpretation of those memories. Copyright © 2017 International Society for Traumatic Stress Studies.

BRCA1-IRIS regulates cyclin D1 expression in breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakuci, Enkeleda; Mahner, Sven; DiRenzo, James

2006-10-01

The regulator of cell cycle progression, cyclin D1, is up-regulated in breast cancer cells; its expression is, in part, dependent on ER{alpha} signaling. However, many ER{alpha}-negative tumors and tumor cell lines (e.g., SKBR3) also show over-expression of cyclin D1. This suggests that, in addition to ER{alpha} signaling, cyclin D1 expression is under the control of other signaling pathways; these pathways may even be over-expressed in the ER{alpha}-negative cells. We previously noticed that both ER{alpha}-positive and -negative cell lines over-express BRCA1-IRIS mRNA and protein. Furthermore, the level of over-expression of BRCA1-IRIS in ER{alpha}-negative cell lines even exceeded its over-expression level inmore » ER{alpha}-positive cell lines. In this study, we show that: (1) BRCA1-IRIS forms complex with two of the nuclear receptor co-activators, namely, SRC1 and SRC3 (AIB1) in an ER{alpha}-independent manner. (2) BRCA1-IRIS alone, or in connection with co-activators, is recruited to the cyclin D1 promoter through its binding to c-Jun/AP1 complex; this binding activates the cyclin D1 expression. (3) Over-expression of BRCA1-IRIS in breast cells over-activates JNK/c-Jun; this leads to the induction of cyclin D1 expression and cellular proliferation. (4) BRCA1-IRIS activation of JNK/c-Jun/AP1 appears to account for this, because in cells that were depleted from BRCA1-IRIS, JNK remained inactive. However, depletion of SRC1 or SRC3 instead reduced c-Jun expression. Our data suggest that this novel signaling pathway links BRCA1-IRIS to cellular proliferation through c-Jun/AP1 nuclear pathway; finally, this culminates in the increased expression of the cyclin D1 gene.« less

Epigenetic suppression of neprilysin regulates breast cancer invasion

PubMed Central

Stephen, H M; Khoury, R J; Majmudar, P R; Blaylock, T; Hawkins, K; Salama, M S; Scott, M D; Cosminsky, B; Utreja, N K; Britt, J; Conway, R E

2016-01-01

In women, invasive breast cancer is the second most common cancer and the second cause of cancer-related death. Therefore, identifying novel regulators of breast cancer invasion could lead to additional biomarkers and therapeutic targets. Neprilysin, a cell-surface enzyme that cleaves and inactivates a number of substrates including endothelin-1 (ET1), has been implicated in breast cancer, but whether neprilysin promotes or inhibits breast cancer cell progression and metastasis is unclear. Here, we asked whether neprilysin expression predicts and functionally regulates breast cancer cell invasion. RT–PCR and flow cytometry analysis of MDA-MB-231 and MCF-7 breast cancer cell lines revealed decreased neprilysin expression compared with normal epithelial cells. Expression was also suppressed in invasive ductal carcinoma (IDC) compared with normal tissue. In addition, in vtro invasion assays demonstrated that neprilysin overexpression decreased breast cancer cell invasion, whereas neprilysin suppression augmented invasion. Furthermore, inhibiting neprilysin in MCF-7 breast cancer cells increased ET1 levels significantly, whereas overexpressing neprilysin decreased extracellular-signal related kinase (ERK) activation, indicating that neprilysin negatively regulates ET1-induced activation of mitogen-activated protein kinase (MAPK) signaling. To determine whether neprilysin was epigenetically suppressed in breast cancer, we performed bisulfite conversion analysis of breast cancer cells and clinical tumor samples. We found that the neprilysin promoter was hypermethylated in breast cancer; chemical reversal of methylation in MDA-MB-231 cells reactivated neprilysin expression and inhibited cancer cell invasion. Analysis of cancer databases revealed that neprilysin methylation significantly associates with survival in stage I IDC and estrogen receptor-negative breast cancer subtypes. These results demonstrate that neprilysin negatively regulates the ET axis in breast cancer, and epigenetic suppression of neprilysin in invasive breast cancer cells enables invasion. Together, this implicates neprilysin as an important regulator of breast cancer invasion and clarifies its utility as a potential biomarker for invasive breast cancer. PMID:26950599

Epigenetic suppression of neprilysin regulates breast cancer invasion.

PubMed

Stephen, H M; Khoury, R J; Majmudar, P R; Blaylock, T; Hawkins, K; Salama, M S; Scott, M D; Cosminsky, B; Utreja, N K; Britt, J; Conway, R E

2016-03-07

In women, invasive breast cancer is the second most common cancer and the second cause of cancer-related death. Therefore, identifying novel regulators of breast cancer invasion could lead to additional biomarkers and therapeutic targets. Neprilysin, a cell-surface enzyme that cleaves and inactivates a number of substrates including endothelin-1 (ET1), has been implicated in breast cancer, but whether neprilysin promotes or inhibits breast cancer cell progression and metastasis is unclear. Here, we asked whether neprilysin expression predicts and functionally regulates breast cancer cell invasion. RT-PCR and flow cytometry analysis of MDA-MB-231 and MCF-7 breast cancer cell lines revealed decreased neprilysin expression compared with normal epithelial cells. Expression was also suppressed in invasive ductal carcinoma (IDC) compared with normal tissue. In addition, in vtro invasion assays demonstrated that neprilysin overexpression decreased breast cancer cell invasion, whereas neprilysin suppression augmented invasion. Furthermore, inhibiting neprilysin in MCF-7 breast cancer cells increased ET1 levels significantly, whereas overexpressing neprilysin decreased extracellular-signal related kinase (ERK) activation, indicating that neprilysin negatively regulates ET1-induced activation of mitogen-activated protein kinase (MAPK) signaling. To determine whether neprilysin was epigenetically suppressed in breast cancer, we performed bisulfite conversion analysis of breast cancer cells and clinical tumor samples. We found that the neprilysin promoter was hypermethylated in breast cancer; chemical reversal of methylation in MDA-MB-231 cells reactivated neprilysin expression and inhibited cancer cell invasion. Analysis of cancer databases revealed that neprilysin methylation significantly associates with survival in stage I IDC and estrogen receptor-negative breast cancer subtypes. These results demonstrate that neprilysin negatively regulates the ET axis in breast cancer, and epigenetic suppression of neprilysin in invasive breast cancer cells enables invasion. Together, this implicates neprilysin as an important regulator of breast cancer invasion and clarifies its utility as a potential biomarker for invasive breast cancer.

Negative transcriptional regulation of mitochondrial transcription factor A (TFAM) by nuclear TFAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Eun Jin; Kang, Young Cheol; Park, Wook-Ha

2014-07-18

Highlights: • TFAM localizes in nuclei and mitochondria of neuronal cells. • Nuclear TFAM does not bind the Tfam promoter. • Nuclear TFAM reduced the Tfam promoter activity via suppressing NRF-1 activity. • A novel self-negative feedback regulation of Tfam gene expression is explored. • FAM may play different roles depending on its subcellular localizations. - Abstract: The nuclear DNA-encoded mitochondrial transcription factor A (TFAM) is synthesized in cytoplasm and transported into mitochondria. TFAM enhances both transcription and replication of mitochondrial DNA. It is unclear, however, whether TFAM plays a role in regulating nuclear gene expression. Here, we demonstrated thatmore » TFAM was localized to the nucleus and mitochondria by immunostaining, subcellular fractionation, and TFAM-green fluorescent protein hybrid protein studies. In HT22 hippocampal neuronal cells, human TFAM (hTFAM) overexpression suppressed human Tfam promoter-mediated luciferase activity in a dose-dependent manner. The mitochondria targeting sequence-deficient hTFAM also repressed Tfam promoter activity to the same degree as hTFAM. It indicated that nuclear hTFAM suppressed Tfam expression without modulating mitochondrial activity. The repression required for nuclear respiratory factor-1 (NRF-1), but hTFAM did not bind to the NRF-1 binding site of its promoter. TFAM was co-immunoprecipitated with NRF-1. Taken together, we suggest that nuclear TFAM down-regulate its own gene expression as a NRF-1 repressor, showing that TFAM may play different roles depending on its subcellular localizations.« less

Negative Regulation of NF-κB by the ING4 Tumor Suppressor in Breast Cancer

PubMed Central

Byron, Sara A.; Min, Elizabeth; Thal, Tanya S.; Hostetter, Galen; Watanabe, Aprill T.; Azorsa, David O.; Little, Tanya H.; Tapia, Coya; Kim, Suwon

2012-01-01

Nuclear Factor kappa B (NF-κB) is a key mediator of normal immune response but contributes to aggressive cancer cell phenotypes when aberrantly activated. Here we present evidence that the Inhibitor of Growth 4 (ING4) tumor suppressor negatively regulates NF-κB in breast cancer. We surveyed primary breast tumor samples for ING4 protein expression using tissue microarrays and a newly generated antibody. We found that 34% of tumors expressed undetectable to low levels of the ING4 protein (n = 227). Tumors with low ING4 expression were frequently large in size, high grade, and lymph node positive, suggesting that down-regulation of ING4 may contribute to breast cancer progression. In the same tumor set, we found that low ING4 expression correlated with high levels of nuclear phosphorylated p65/RelA (p-p65), an activated form of NF-κB (p = 0.018). Fifty seven percent of ING4-low/p-p65-high tumors were lymph node-positive, indicating a high metastatic tendency of these tumors. Conversely, ectopic expression of ING4 inhibited p65/RelA phosphorylation in T47D and MCF7 breast cancer cells. In addition, ING4 suppressed PMA-induced cell invasion and NF-κB-target gene expression in T47D cells, indicating that ING4 inhibited NF-κB activity in breast cancer cells. Supportive of the ING4 function in the regulation of NF-κB-target gene expression, we found that ING4 expression levels inversely correlated with the expression of NF-κB-target genes in primary breast tumors by analyzing public gene expression datasets. Moreover, low ING4 expression or high expression of the gene signature composed of a subset of ING4-repressed NF-κB-target genes was associated with reduced disease-free survival in breast cancer patients. Taken together, we conclude that ING4 negatively regulates NF-κB in breast cancer. Consequently, down-regulation of ING4 leads to activation of NF-κB, contributing to tumor progression and reduced disease-free patient survival in breast cancer. PMID:23056468

Class IA phosphoinositide 3-kinase regulates heart size and physiological cardiac hypertrophy.

PubMed

Luo, Ji; McMullen, Julie R; Sobkiw, Cassandra L; Zhang, Li; Dorfman, Adam L; Sherwood, Megan C; Logsdon, M Nicole; Horner, James W; DePinho, Ronald A; Izumo, Seigo; Cantley, Lewis C

2005-11-01

Class I(A) phosphoinositide 3-kinases (PI3Ks) are activated by growth factor receptors, and they regulate, among other processes, cell growth and organ size. Studies using transgenic mice overexpressing constitutively active and dominant negative forms of the p110alpha catalytic subunit of class I(A) PI3K have implicated the role of this enzyme in regulating heart size and physiological cardiac hypertrophy. To further understand the role of class I(A) PI3K in controlling heart growth and to circumvent potential complications from the overexpression of dominant negative and constitutively active proteins, we generated mice with muscle-specific deletion of the p85alpha regulatory subunit and germ line deletion of the p85beta regulatory subunit of class I(A) PI3K. Here we show that mice with cardiac deletion of both p85 subunits exhibit attenuated Akt signaling in the heart, reduced heart size, and altered cardiac gene expression. Furthermore, exercise-induced cardiac hypertrophy is also attenuated in the p85 knockout hearts. Despite such defects in postnatal developmental growth and physiological hypertrophy, the p85 knockout hearts exhibit normal contractility and myocardial histology. Our results therefore provide strong genetic evidence that class I(A) PI3Ks are critical regulators for the developmental growth and physiological hypertrophy of the heart.

Negative Regulation of Anthocynanin Biosynthesis in Arabidopsis by a miR156-Targeted SPL Transcription Factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gou, J.Y.; Liu, C.; Felippes, F. F.

2011-04-01

Flavonoids are synthesized through an important metabolic pathway that leads to the production of diverse secondary metabolites, including anthocyanins, flavonols, flavones, and proanthocyanidins. Anthocyanins and flavonols are derived from Phe and share common precursors, dihydroflavonols, which are substrates for both flavonol synthase and dihydroflavonol 4-reductase. In the stems of Arabidopsis thaliana, anthocyanins accumulate in an acropetal manner, with the highest level at the junction between rosette and stem. We show here that this accumulation pattern is under the regulation of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, which are deeply conserved and known to have important roles in regulating phasemore » change and flowering. Increased miR156 activity promotes accumulation of anthocyanins, whereas reduced miR156 activity results in high levels of flavonols. We further provide evidence that at least one of the miR156 targets, SPL9, negatively regulates anthocyanin accumulation by directly preventing expression of anthocyanin biosynthetic genes through destabilization of a MYB-bHLH-WD40 transcriptional activation complex. Our results reveal a direct link between the transition to flowering and secondary metabolism and provide a potential target for manipulation of anthocyanin and flavonol content in plants.« less

Modulating inflammation through the negative regulation of NF-κB signaling.

PubMed

Rothschild, Daniel E; McDaniel, Dylan K; Ringel-Scaia, Veronica M; Allen, Irving C

2018-02-01

Immune system activation is essential to thwart the invasion of pathogens and respond appropriately to tissue damage. However, uncontrolled inflammation can result in extensive collateral damage underlying a diverse range of auto-inflammatory, hyper-inflammatory, and neoplastic diseases. The NF-κB signaling pathway lies at the heart of the immune system and functions as a master regulator of gene transcription. Thus, this signaling cascade is heavily targeted by mechanisms designed to attenuate overzealous inflammation and promote resolution. Mechanisms associated with the negative regulation of NF-κB signaling are currently under intense investigation and have yet to be fully elucidated. Here, we provide an overview of mechanisms that negatively regulate NF-κB signaling through either attenuation of signal transduction, inhibition of posttranscriptional signaling, or interference with posttranslational modifications of key pathway components. While the regulators discussed for each group are far from comprehensive, they exemplify common mechanistic approaches that inhibit this critical biochemical signaling cascade. Despite their diversity, a commonality among these regulators is their selection of specific targets at key inflection points in the pathway, such as TNF-receptor-associated factor family members or essential kinases. A better understanding of these negative regulatory mechanisms will be essential to gain greater insight related to the maintenance of immune system homeostasis and inflammation resolution. These processes are vital elements of disease pathology and have important implications for targeted therapeutic strategies. ©2018 Society for Leukocyte Biology.

Silencing OsSLR1 enhances the resistance of rice to the brown planthopper Nilaparvata lugens.

PubMed

Zhang, Jin; Luo, Ting; Wang, Wanwan; Cao, Tiantian; Li, Ran; Lou, Yonggen

2017-10-01

DELLA proteins, negative regulators of the gibberellin (GA) pathway, play important roles in plant growth, development and pathogen resistance by regulating multiple phytohormone signals. Yet, whether and how they regulate plant herbivore resistance remain unknown. We found that the expression of the rice DELLA gene OsSLR1 was down-regulated by an infestation of female adults of the brown planthopper (BPH) Nilaparvata lugens. On one hand, OsSLR1 positively regulated BPH-induced levels of two mitogen-activated protein kinase and four WRKY transcripts, and of jasmonic acid, ethylene and H 2 O 2 . On the other hand, silencing OsSLR1 enhanced constitutive levels of defence-related compounds, phenolic acids, lignin and cellulose, as well as the resistance of rice to BPH in the laboratory and in the field. The increased resistance in rice with silencing of OsSLR1 is probably due to impaired JA and ethylene pathways, and, at least in part, to the increased lignin level and mechanical hardness of rice leaf sheaths. Our findings illustrate that OsSLR1, acting as an early negative regulator, plays an important role in regulating the resistance of rice to BPH by activating appropriate defence-related signalling pathways and compounds. Moreover, our data also provide new insights into relationships between plant growth and defence. © 2017 John Wiley & Sons Ltd.

Protein Phosphotyrosine Phosphatase 1B (PTP1B) in Calpain-dependent Feedback Regulation of Vascular Endothelial Growth Factor Receptor (VEGFR2) in Endothelial Cells: IMPLICATIONS IN VEGF-DEPENDENT ANGIOGENESIS AND DIABETIC WOUND HEALING.

PubMed

Zhang, Yixuan; Li, Qiang; Youn, Ji Youn; Cai, Hua

2017-01-13

The VEGF/VEGFR2/Akt/eNOS/NO pathway is essential to VEGF-induced angiogenesis. We have previously discovered a novel role of calpain in mediating VEGF-induced PI3K/AMPK/Akt/eNOS activation through Ezrin. Here, we sought to identify possible feedback regulation of VEGFR2 by calpain via its substrate protein phosphotyrosine phosphatase 1B (PTP1B), and the relevance of this pathway to VEGF-induced angiogenesis, especially in diabetic wound healing. Overexpression of PTP1B inhibited VEGF-induced VEGFR2 and Akt phosphorylation in bovine aortic endothelial cells, while PTP1B siRNA increased both, implicating negative regulation of VEGFR2 by PTP1B. Calpain inhibitor ALLN induced VEGFR2 activation, which can be completely blocked by PTP1B overexpression. Calpain activation induced by overexpression or Ca/A23187 resulted in PTP1B cleavage, which can be blocked by ALLN. Moreover, calpain activation inhibited VEGF-induced VEGFR2 phosphorylation, which can be restored by PTP1B siRNA. These data implicate calpain/PTP1B negative feedback regulation of VEGFR2, in addition to the primary signaling pathway of VEGF/VEGFR2/calpain/PI3K/AMPK/Akt/eNOS. We next examined a potential role of PTP1B in VEGF-induced angiogenesis. Endothelial cells transfected with PTP1B siRNA showed faster wound closure in response to VEGF. Aortic discs isolated from PTP1B siRNA-transfected mice also had augmented endothelial outgrowth. Importantly, PTP1B inhibition and/or calpain overexpression significantly accelerated wound healing in STZ-induced diabetic mice. In conclusion, our data for the first time demonstrate a calpain/PTP1B/VEGFR2 negative feedback loop in the regulation of VEGF-induced angiogenesis. Modulation of local PTP1B and/or calpain activities may prove beneficial in the treatment of impaired wound healing in diabetes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Kruppel-like factor 2 (KLF2) regulates proinflammatory activation of monocytes

PubMed Central

Das, Hiranmoy; Kumar, Ajay; Lin, Zhiyong; Patino, Willmar D.; Hwang, Paul M.; Feinberg, Mark W.; Majumder, Pradip K.; Jain, Mukesh K.

2006-01-01

The mechanisms regulating activation of monocytes remain incompletely understood. Herein we provide evidence that Kruppel-like factor 2 (KLF2) inhibits proinflammatory activation of monocytes. In vitro, KLF2 expression in monocytes is reduced by cytokine activation or differentiation. Consistent with this observation, KLF2 expression in circulating monocytes is reduced in patients with chronic inflammatory conditions such as coronary artery disease. Adenoviral overexpression of KLF2 inhibits the LPS-mediated induction of proinflammatory factors, cytokines, and chemokines and reduces phagocytosis. Conversely, short interfering RNA-mediated reduction in KLF2 increased inflammatory gene expression. Reconstitution of immunodeficient mice with KLF2-overexpressing monocytes significantly reduced carrageenan-induced acute paw edema formation. Mechanistically, KLF2 inhibits the transcriptional activity of both NF-κB and activator protein 1, in part by means of recruitment of transcriptional coactivator p300/CBP-associated factor. These observations identify KLF2 as a novel negative regulator of monocytic activation. PMID:16617118

C/EBP beta regulation of the tumor necrosis factor alpha gene.

PubMed Central

Pope, R M; Leutz, A; Ness, S A

1994-01-01

Activated macrophages contribute to chronic inflammation by the secretion of cytokines and proteinases. Tumor necrosis factor alpha (TNF alpha) is particularly important in this process because of its ability to regulate other inflammatory mediators in an autocrine and paracrine fashion. The mechanism(s) responsible for the cell type-specific regulation of TNF alpha is not known. We present data to show that the expression of TNF alpha is regulated by the transcription factor C/EBP beta (NF-IL6). C/EBP beta activated the TNF alpha gene promoter in cotransfection assays and bound to it at a site which failed to bind the closely related protein C/EBP alpha. Finally, a dominant-negative version of C/EBP beta blocked TNF alpha promoter activation in myeloid cells. Our results implicate C/EBP beta as an important regulator of TNF alpha by myelomonocytic cells. Images PMID:7929820

GlnR-Mediated Regulation of ectABCD Transcription Expands the Role of the GlnR Regulon to Osmotic Stress Management.

PubMed

Shao, ZhiHui; Deng, WanXin; Li, ShiYuan; He, JuanMei; Ren, ShuangXi; Huang, WeiRen; Lu, YinHua; Zhao, GuoPing; Cai, ZhiMing; Wang, Jin

2015-10-01

Ectoine and hydroxyectoine are excellent compatible solutes for bacteria to deal with environmental osmotic stress and temperature damages. The biosynthesis cluster of ectoine and hydroxyectoine is widespread among microorganisms, and its expression is activated by high salinity and temperature changes. So far, little is known about the mechanism of the regulation of the transcription of ect genes and only two MarR family regulators (EctR1 in methylobacteria and the EctR1-related regulator CosR in Vibrio cholerae) have been found to negatively regulate the expression of ect genes. Here, we characterize GlnR, the global regulator for nitrogen metabolism in actinomycetes, as a negative regulator for the transcription of ectoine/hydroxyectoine biosynthetic genes (ect operon) in Streptomyces coelicolor. The physiological role of this transcriptional repression by GlnR is proposed to protect the intracellular glutamate pool, which acts as a key nitrogen donor for both the nitrogen metabolism and the ectoine/hydroxyectoine biosynthesis. High salinity is deleterious, and cells must evolve sophisticated mechanisms to cope with this osmotic stress. Although production of ectoine and hydroxyectoine is one of the most frequently adopted strategies, the in-depth mechanism of regulation of their biosynthesis is less understood. So far, only two MarR family negative regulators, EctR1 and CosR, have been identified in methylobacteria and Vibrio, respectively. Here, our work demonstrates that GlnR, the global regulator for nitrogen metabolism, is a negative transcriptional regulator for ect genes in Streptomyces coelicolor. Moreover, a close relationship is found between nitrogen metabolism and osmotic resistance, and GlnR-mediated regulation of ect transcription is proposed to protect the intracellular glutamate pool. Meanwhile, the work reveals the multiple roles of GlnR in bacterial physiology. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Lack of Csk-mediated negative regulation in a unicellular SRC kinase.

PubMed

Schultheiss, Kira P; Suga, Hiroshi; Ruiz-Trillo, Iñaki; Miller, W Todd

2012-10-16

Phosphotyrosine-based signaling plays a vital role in cellular communication in multicellular organisms. Unexpectedly, unicellular choanoflagellates (the closest phylogenetic group to metazoans) possess numbers of tyrosine kinases that are comparable to those in complex metazoans. Here, we have characterized tyrosine kinases from the filasterean Capsaspora owczarzaki, a unicellular protist representing the sister group to choanoflagellates and metazoans. Two Src-like tyrosine kinases have been identified in C. owczarzaki (CoSrc1 and CoSrc2), both of which have the arrangement of SH3, SH2, and catalytic domains seen in mammalian Src kinases. In Capsaspora cells, CoSrc1 and CoSrc2 localize to punctate structures in filopodia that may represent primordial focal adhesions. We have cloned, expressed, and purified both enzymes. CoSrc1 and CoSrc2 are active tyrosine kinases. Mammalian Src kinases are normally regulated in a reciprocal fashion by autophosphorylation in the activation loop (which increases activity) and by Csk-mediated phosphorylation of the C-terminal tail (which inhibits activity). Similar to mammalian Src kinases, the enzymatic activities of CoSrc1 and CoSrc2 are increased by autophosphorylation in the activation loop. We have identified a Csk-like kinase (CoCsk) in the genome of C. owczarzaki. We cloned, expressed, and purified CoCsk and found that it has no measurable tyrosine kinase activity. Furthermore, CoCsk does not phosphorylate or regulate CoSrc1 or CoSrc2 in cells or in vitro, and CoSrc1 and CoSrc2 are active in Capsaspora cell lysates. Thus, the function of Csk as a negative regulator of Src family kinases appears to have arisen with the emergence of metazoans.

TIS21/(BTG2) negatively regulates estradiol-stimulated expansion of hematopoietic stem cells by derepressing Akt phosphorylation and inhibiting mTOR signal transduction.

PubMed

Kim, Bong Cho; Ryu, Min Sook; Oh, S Paul; Lim, In Kyoung

2008-09-01

It has been known that 12-O-tetradecanoyl phorbol-13-acetate-inducible sequence 21 (TIS21), ortholog of human B-cell translocation gene 2, regulates expansions of stage-specific thymocytes and hematopoietic progenitors. In the present study, lineage-negative (Lin(-))/stem cell antigen-1-positive (Sca-1+)/c-Kit+ (LSK) cell content was significantly elevated in bone marrow (BM) of TIS21-knockout (TIS21(-/-)) female mice, suggesting 17beta-estradiol (E(2))-regulated progenitor expansion. E(2) induced DNA synthesis and cell proliferation of mouse embryonic fibroblasts (MEFs) isolated from TIS21(-/-) mice, but not wild type (WT). In contrast to WT, E(2) failed to activate protein kinase B (Akt) in the TIS21(-/-) MEFs, independent of extracellular signal-regulated kinase 1/2 (Erk1/2) activation. Despite attenuation of Akt activation, mammalian target of rapamycin (mTOR) was constitutively activated in the TIS21(-/-) MEFs. Furthermore, mitogen-activated protein kinase 1/2 inhibitor or knockdown of Erk1 could restore activation of Akt and downregulate mTOR. Immunoprecipitation showed Akt preferentially bound to phosphorylated Erk1/2 (p-Erk1/2) in TIS21(-/-) cells, but reconstitution of TIS21 inhibited their interaction. E(2)-injected TIS21(-/-) male mice also increased LSK cells in BM. Taken together, expansion of hematopoietic progenitors in TIS21(-/-) female mice might be through inhibition of Akt activation, and constitutive activation of mTOR via preferential binding of TIS21 to E(2)-induced p-Erk1/2, compared with that of Akt. Our results suggest that TIS21 plays a pivotal role in maintaining the hematopoietic stem cell compartment and hematopoiesis.

The negative cell cycle regulator, Tob (transducer of ErbB-2), is involved in motor skill learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Xinming; Shanghai Institute of Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031; Gao Xiang

Tob (transducer of ErbB-2) is a negative cell cycle regulator with anti-proliferative activity in peripheral tissues. Our previous study identified Tob as a protein involved in hippocampus-dependent memory consolidation (M.L. Jin, X.M. Wang, Y.Y. Tu, X.H. Zhang, X. Gao, N. Guo, Z.Q. Xie, G.P. Zhao, N.H. Jing, B.M. Li, Y.Yu, The negative cell cycle regulator, Tob (Transducer of ErbB-2), is a multifunctional protein involved in hippocampus-dependent learning and memory, Neuroscience 131 (2005) 647-659). Here, we provide evidence that Tob in the central nervous system is engaged in acquisition of motor skill. Tob has a relatively high expression in the cerebellum.more » Tob expression is up-regulated in the cerebellum after rats receive training on a rotarod-running task. Rats infused with Tob antisense oligonucleotides into the 4th ventricle exhibit a severe deficit in running on a rotating rod or walking across a horizontally elevated beam.« less

Self-determined motivation and physical activity in children and adolescents: a systematic review and meta-analysis.

PubMed

B Owen, Katherine; Smith, Jordan; Lubans, David R; Ng, Johan Y Y; Lonsdale, Chris

2014-10-01

Self-determination theory is used as a framework for examining the relation between motivation and physical activity. The purpose of this review was to systematically review studies that assessed the association between self-determined motivation and physical activity levels in children and adolescents. We searched electronic databases in April 2013. Included studies assessed the relation between motivation (as outlined in self-determination theory) and physical activity in children and adolescents. Forty-six studies (n=15,984 participants) met the inclusion criteria. Meta-analysis indicated that overall levels of self-determined motivation had a weak to moderate, positive associations with physical activity (ρ=.21 to .31). Autonomous forms of motivation (i.e., intrinsic motivation and identified regulation) had moderate, positive associations with physical activity (ρ=.27 to .38), whereas controlled forms of motivation (i.e., introjection and external regulation) had weak, negative associations with physical activity (ρ=-.03 to -.17). Amotivation had a weak, negative association with physical activity (ρ=-.11 to -.21). Evidence provides some support for self-determination theory tenets. However, there was substantial heterogeneity in most associations and many studies had methodological shortcomings. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Mothers' depressive symptoms and children's externalizing behavior: Children's negative emotionality in the development of hostile attributions.

PubMed

Wang, Yiji; Dix, Theodore

2017-03-01

This study examined processes that might account for why negatively emotional children are at high risk for externalizing behavior problems when raised by mothers with depressive symptoms. Because negative emotionality regulates adaptation to stress, we predicted that it would undermine children's adjustment to mothers' depressive symptoms by increasing child emotions likely to elicit reciprocal negativity from depressed mothers, bias negatively children's attributions about others, and activate difficult-to-control oppositional responses. In a large sample (N = 1,082) evaluated from 6 months to second grade, results showed that, when mothers had depressive symptoms early in the child's development, children who were high in negative emotionality-but not those who were low-displayed increased risk for externalizing problems in second grade. This risk reflected tendencies for negatively emotional children, when raised by mothers with depressive symptoms, to develop hostile attributions about others and poor self-regulation of the negativity these attributions promote. The findings suggest that, when mothers with depressive symptoms raise negatively emotional children, children's risk for externalizing behavior problems may reflect tendencies for high negative emotion in children and reciprocal negativity in the dyad to undermine the development of attributional and self-regulatory processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

A Quantitative RNAi Screen for JNK Modifiers Identifies Pvr as a Novel Regulator of Drosophila Immune Signaling

PubMed Central

Bond, David; Foley, Edan

2009-01-01

Drosophila melanogaster responds to gram-negative bacterial challenges through the IMD pathway, a signal transduction cassette that is driven by the coordinated activities of JNK, NF-κB and caspase modules. While many modifiers of NF-κB activity were identified in cell culture and in vivo assays, the regulatory apparatus that determines JNK inputs into the IMD pathway is relatively unexplored. In this manuscript, we present the first quantitative screen of the entire genome of Drosophila for novel regulators of JNK activity in the IMD pathway. We identified a large number of gene products that negatively or positively impact on JNK activation in the IMD pathway. In particular, we identified the Pvr receptor tyrosine kinase as a potent inhibitor of JNK activation. In a series of in vivo and cell culture assays, we demonstrated that activation of the IMD pathway drives JNK-dependent expression of the Pvr ligands, Pvf2 and Pvf3, which in turn act through the Pvr/ERK MAP kinase pathway to attenuate the JNK and NF-κB arms of the IMD pathway. Our data illuminate a poorly understood arm of a critical and evolutionarily conserved innate immune response. Furthermore, given the pleiotropic involvement of JNK in eukaryotic cell biology, we believe that many of the novel regulators identified in this screen are of interest beyond immune signaling. PMID:19893628

Palmitate-induced ER stress and subsequent C 1 HOP activation attenuates leptin and IGF1expression in the brain

USDA-ARS?s Scientific Manuscript database

Background: The peptide hormones insulin-like growth factor-1 (IGF1) and leptin mediate a myriad of biological effects both in the peripheral and central nervous systems. The transcription of these two hormones is regulated by the transcription factor C/EBPa, which in turn is negatively regulated by...

The C-Terminal Domain of Nrf1 Negatively Regulates the Full-Length CNC-bZIP Factor and Its Shorter Isoform LCR-F1/Nrf1β; Both Are Also Inhibited by the Small Dominant-Negative Nrf1γ/δ Isoforms that Down-Regulate ARE-Battery Gene Expression

PubMed Central

Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

2014-01-01

The C-terminal domain (CTD, aa 686–741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ. PMID:25290918

GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters.

PubMed

Ramesh, Sunita A; Tyerman, Stephen D; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A; Ryan, Peter R; Gilliham, Matthew; Gillham, Matthew

2015-07-29

The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms.

GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters

PubMed Central

Ramesh, Sunita A.; Tyerman, Stephen D.; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A.; Ryan, Peter R.; Gillham, Matthew

2015-01-01

The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms. PMID:26219411

The maize WRKY transcription factor ZmWRKY17 negatively regulates salt stress tolerance in transgenic Arabidopsis plants.

PubMed

Cai, Ronghao; Dai, Wei; Zhang, Congsheng; Wang, Yan; Wu, Min; Zhao, Yang; Ma, Qing; Xiang, Yan; Cheng, Beijiu

2017-12-01

We cloned and characterized the ZmWRKY17 gene from maize. Overexpression of ZmWRKY17 in Arabidopsis led to increased sensitivity to salt stress and decreased ABA sensitivity through regulating the expression of some ABA- and stress-responsive genes. The WRKY transcription factors have been reported to function as positive or negative regulators in many different biological processes including plant development, defense regulation and stress response. This study isolated a maize WRKY gene, ZmWRKY17, and characterized its role in tolerance to salt stress by generating transgenic Arabidopsis plants. Expression of the ZmWRKY17 was up-regulated by drought, salt and abscisic acid (ABA) treatments. ZmWRKY17 was localized in the nucleus with no transcriptional activation in yeast. Yeast one-hybrid assay showed that ZmWRKY17 can specifically bind to W-box, and it can activate W-box-dependent transcription in planta. Heterologous overexpression of ZmWRKY17 in Arabidopsis remarkably reduced plant tolerance to salt stress, as determined through physiological analyses of the cotyledons greening rate, root growth, relative electrical leakage and malondialdehyde content. Additionally, ZmWRKY17 transgenic plants showed decreased sensitivity to ABA during seed germination and early seedling growth. Transgenic plants accumulated higher content of ABA than wild-type (WT) plants under NaCl condition. Transcriptome and quantitative real-time PCR analyses revealed that some stress-related genes in transgenic seedlings showed lower expression level than that in the WT when treated with NaCl. Taken together, these results suggest that ZmWRKY17 may act as a negative regulator involved in the salt stress responses through ABA signalling.

Caveolae are negative regulators of transforming growth factor-beta1 signaling in ureteral smooth muscle cells.

PubMed

Stehr, Maximilian; Estrada, Carlos R; Khoury, Joseph; Danciu, Theodora E; Sullivan, Maryrose P; Peters, Craig A; Solomon, Keith R; Freeman, Michael R; Adam, Rosalyn M

2004-12-01

The mechanisms underlying ureteral cell regulation are largely unknown. Previous studies have identified lipid rafts/caveolae as regulators of growth stimulatory signals in ureteral smooth muscle cells (USMCs). In this study we determined whether growth inhibitory signaling by transforming growth factor-beta1 (TGF-beta1) is also regulated by caveolae in USMC. Expression of components of the TGF-beta1 signaling axis in USMCs was determined by immunoblot and mRNA analyses. Growth regulatory activity of TGF-beta1 was assessed by H-thymidine incorporation. In select experiments caveolae were disrupted reversibly by cholesterol depletion and replenishment prior to TGF-beta1 treatment. TGF-beta1-responsive gene expression was evaluated using the TGF-beta1 responsive promoter-reporter construct 3TP-Lux. USMCs expressed TGF-beta1, types I and II TGF-beta1 receptors, and the effector Smad-2. TGF-beta1 potently inhibited DNA synthesis in USMCs (IC50 60 pM). TGF-beta1 mediated DNA synthesis inhibition was potentiated following the disruption of caveolae by cholesterol depletion. This effect was reversible with membrane cholesterol restoration. TGF-beta1 stimulated gene activity was augmented by caveolae disruption, while caveolae reformation returned promoter activity to baseline levels. TGF-beta1 is a potent growth inhibitor of USMCs and its activity can be enhanced by caveolae ablation. These findings suggest a role for TGF-beta1 in the growth regulation of normal ureteral cells and implicate caveolar membrane domains in the negative regulation of TGF-beta1 signaling. These studies may be relevant to ureteral pathologies that are characterized by smooth muscle dysplasia.

Development of Small Molecule Activators of Protein Phosphotase 2A (SMAPs) for the Treatment of Castration Resistant Prostate Cancer

DTIC Science & Technology

2016-10-01

views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the...fide tumor suppressor, and a key negative regulator of critical oncogenic proteins including the androgen receptor ( AR ), Akt, Erk, and Myc. We have...the AR and other key PP2A regulated oncogenic pathways. Purpose: We hypothesize that our novel derivative DT-061 activates PP2A, downregulates key

Role of Merlin/NF2 in mTOR Signaling and Meningioma Growth

DTIC Science & Technology

2012-04-01

this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson...this research project is to mechanistically define how merlin regulates mTORC1 signaling, to examine signaling downstream of mTORC2 and to validate the...TSC1-TSC2 protein complex. Similar to TSC proteins, merlin negatively regulates mTORC1 and positively regulates mTORC2 However, contrary to activation

Enhancing well-being at work: The role of emotion regulation skills as personal resources.

PubMed

Buruck, Gabriele; Dörfel, Denise; Kugler, Joachim; Brom, Sarah Susanne

2016-10-01

Dealing with negative emotions is a crucial work demand, particularly for employees in health care. Job resources (e.g., autonomy, social support, or reward) but also personal resources (such as emotion regulation strategies) might reduce job stress and support well-being. Following this, the present study focused on strengthening emotion regulation as 1 way of dealing with high job demands. The aim of this study was to evaluate the impact of a standardized emotion regulation training (Affect Regulation Training [ART]; Berking, 2010) to improve emotion regulation skills and well-being of employees in elderly health care. Therefore, 96 elderly care workers filled out an established questionnaire of emotion regulation skills as well as a measure of well-being at pretreatment, posttreatment and at 6-month follow-up. The findings show that the ART fosters emotion regulation skills. In particularly, acceptance, tolerance, and modification of negative emotions was enhanced in the training groups in comparison to a control-group. Modification, meaning the ability to actively change emotions, improved even more over the follow-up-period. Simultaneously, well-being of participants increased over all measurement time points in the ART-group compared with the control-group. Additionally, the improvement in emotion regulation skills from pre to posttreatment was related to well-being at follow-up. In summary, our results support the ART as an effective intervention for dealing with negative emotions and to enhance well-being among employees in elderly care. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Cultural differences in hedonic emotion regulation after a negative event.

PubMed

Miyamoto, Yuri; Ma, Xiaoming; Petermann, Amelia G

2014-08-01

Beliefs about emotions can influence how people regulate their emotions. The present research examined whether Eastern dialectical beliefs about negative emotions lead to cultural differences in how people regulate their emotions after experiencing a negative event. We hypothesized that, because of dialectical beliefs about negative emotions prevalent in Eastern culture, Easterners are less motivated than Westerners to engage in hedonic emotion regulation-up-regulation of positive emotions and down-regulation of negative emotions. By assessing online reactions to a recent negative event, Study 1 found that European Americans are more motivated to engage in hedonic emotion regulation. Furthermore, consistent with the reported motivation to regulate emotion hedonically, European Americans show a steeper decline in negative emotions 1 day later than do Asians. By examining retrospective memory of reactions to a past negative event, Study 2 further showed that cultural differences in hedonic emotion regulation are mediated by cultural differences in dialectical beliefs about motivational and cognitive utility of negative emotions, but not by personal deservingness or self-efficacy beliefs. These findings demonstrate the role of cultural beliefs in shaping emotion regulation and emotional experiences.

PGC-1-related coactivator (PRC) negatively regulates endothelial adhesion of monocytes via inhibition of NF κB activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chengye, Zhan; Daixing, Zhou, E-mail: dxzhou7246@hotmail.com; Qiang, Zhong

2013-09-13

Highlights: •First time to display that LPS downregulate the expression of PRC. •First time to show that PRC inhibits the induction of VCAM-1 and E-selectin. •First time to show that PRC inhibit monocytes attachment to endothelial cells. •First time to display that PRC inhibits transcriptional activity of NF-κB. •PRC protects the respiration rate and suppresses the glycolysis rate against LPS. -- Abstract: PGC-1-related coactivator (PRC) is a growth-regulated transcriptional cofactor known to activate many of the nuclear genes specifying mitochondrial respiratory function. Endothelial dysfunction is a prominent feature found in many inflammatory diseases. Adhesion molecules, such as VCAM-1, mediate themore » attachment of monocytes to endothelial cells, thereby playing an important role in endothelial inflammation. The effects of PRC in regards to endothelial inflammation remain unknown. In this study, our findings show that PRC can be inhibited by the inflammatory cytokine LPS in cultured human umbilical vein endothelial cells (HUVECs). In the presence of LPS, the expression of endothelial cell adhesion molecular, such as VCAM1 and E-selectin, is found to be increased. These effects can be negated by overexpression of PRC. Importantly, monocyte adhesion to endothelial cells caused by LPS is significantly attenuated by PRC. In addition, overexpression of PRC protects mitochondrial metabolic function and suppresses the rate of glycolysis against LPS. It is also found that overexpression of PRC decreases the transcriptional activity of NF-κB. These findings suggest that PRC is a negative regulator of endothelial inflammation.« less

Genetic variation in MAOA modulates prefrontal cortical regulation of approach-avoidance reactions.

PubMed

Ernst, Lena H; Lutz, Elisabeth; Ehlis, Ann-Christine; Fallgatter, Andreas J; Reif, Andreas; Plichta, Michael M

2013-01-01

Regulation of automatic approach and avoidance behavior requires affective and cognitive control, which are both influenced by a genetic variation in the gene encoding Monoamine Oxidase A (termed MAOA-uVNTR). The current study investigated MAOA genotype as a moderator of prefrontal cortical activation measured with functional near-infrared spectroscopy (fNIRS) in 37 healthy young adults during performance of the approach-avoidance task with positive and negative pictures. Carriers of the low- compared to the high-expressing genetic variant (MAOA-L vs. MAOA-H) showed increasing regulatory activity in the right dorsolateral prefrontal cortex (DLPFC) during incompatible conditions (approach negative, avoid positive). This might have been a compensatory mechanism for stronger emotional reactions as shown in previous studies and might have prevented any influence of incompatibility on behavior. In contrast, fewer errors but also lower activity in the right DLPFC during processing of negative compared to positive stimuli indicated MAOA-H carriers to have used other regulatory areas. This resulted in slower reaction times in incompatible conditions, but--in line with the known better cognitive regulation efficiency--allowed them to perform incompatible reactions without activating the DLPFC as the highest control instance. Carriers of one low- and one high-expressing allele lay as an intermediate group between the reactions of the low- and high-expressing groups. The relatively small sample size and restriction to fNIRS for assessment of cortical activity limit our findings. Nevertheless, these first results suggest monoam-inergic mechanisms to contribute to interindividual differences in the two basic behavioral principles of approach and avoidance and their neuronal correlates. Copyright © 2013 S. Karger AG, Basel.

Emotional reactivity and regulation in individuals with psychopathic traits: Evidence for a disconnect between neurophysiology and self-report.

PubMed

Ellis, Jennifer D; Schroder, Hans S; Patrick, Christopher J; Moser, Jason S

2017-10-01

Individuals with psychopathic traits often demonstrate blunted reactivity to negative emotional stimuli. However, it is not yet clear whether these individuals also have difficulty regulating their emotional responses to negative stimuli. To address this question, participants with varying levels of psychopathic traits (indexed by the Triarchic Measure of Psychopathy; Patrick, 2010) completed a task in which they passively viewed, increased, or decreased their emotions to negative picture stimuli while electrocortical activity was recorded. During passive viewing of negative images, higher boldness, but not higher disinhibition or meanness, was associated with reduced amplitude of the late positive potential (LPP), an ERP that indexes reactivity to emotionally relevant stimuli. However, all participants demonstrated expected enhancement of the LPP when asked to increase their emotional response. Participants did not show expected suppression of the LPP when asked to decrease their emotional response. Contrary to the electrophysiological data, individuals with higher boldness did not self-report experiencing blunted emotional response during passive viewing trials, and they reported experiencing greater emotional reactivity relative to other participants when regulating (e.g., both increasing and decreasing) their emotions. Results suggest inconsistency between physiological and self-report indices of emotion among high-bold individuals during both affective processing and regulation. © 2017 Society for Psychophysiological Research.

Down-Regulation of Negative Emotional Processing by Transcranial Direct Current Stimulation: Effects of Personality Characteristics

PubMed Central

Peña-Gómez, Cleofé; Vidal-Piñeiro, Dídac; Clemente, Immaculada C.; Pascual-Leone, Álvaro; Bartrés-Faz, David

2011-01-01

Evidence from neuroimaging and electrophysiological studies indicates that the left dorsolateral prefrontal cortex (DLPFC) is a core region in emotional processing, particularly during down-regulation of negative emotional conditions. However, emotional regulation is a process subject to major inter-individual differences, some of which may be explained by personality traits. In the present study we used transcranial direct current stimulation (tDCS) over the left DLPFC to investigate whether transiently increasing the activity of this region resulted in changes in the ratings of positive, neutral and negative emotional pictures. Results revealed that anodal, but not cathodal, tDCS reduced the perceived degree of emotional valence for negative stimuli, possibly due to an enhancement of cognitive control of emotional expression. We also aimed to determine whether personality traits (extraversion and neuroticism) might condition the impact of tDCS. We found that individuals with higher scores on the introversion personality dimension were more permeable than extraverts to the modulatory effects of the stimulation. The present study underlines the role of the left DLPFC in emotional regulation, and stresses the importance of considering individual personality characteristics as a relevant variable, although replication is needed given the limited sample size of our study. PMID:21829522

Characterization of an activation-tagged mutant uncovers a role of GLABRA2 in anthocyanin biosynthesis in Arabidopsis

DOE PAGES

Wang, Xiaoyu; Wang, Xianling; Hu, Qingnan; ...

2015-06-17

In Arabidopsis, anthocyanin biosynthesis is controlled by a MYB-bHLH-WD40 (MBW) transcriptional activator complex. The MBW complex activates the transcription of late biosynthesis genes in the flavonoid pathway, leading to the production of anthocyanins. A similar MBW complex regulates epidermal cell fate by activating the transcription of GLABRA2 (GL2), a homeodomain transcription factor required for trichome formation in shoots and non-hair cell formation in roots. Here we provide experimental evidence to show that GL2 also plays a role in regulating anthocyanin biosynthesis in Arabidopsis. From an activation-tagged mutagenized population of Arabidopsis plants, we isolated a dominant, gain-of-function mutant with reduced anthocyanins.more » Molecular cloning revealed that this phenotype is caused by an elevated expression of GL2, thus the mutant was named gl2-1D. Consistent with the view that GL2 acts as a negative regulator of anthocyanin biosynthesis, gl2-1D seedlings accumulated less whereas gl2-3 seedlings accumulated more anthocyanins in response to sucrose. Gene expression analysis indicated that expression of late, but not early, biosynthesis genes in the flavonoid pathway was dramatically reduced in gl2-1D but elevated in gl2-3 mutants. Further analysis showed that expression of some MBW component genes involved in the regulation of late biosynthesis genes was reduced in gl2-1D but elevated in gl2-3 mutants, and chromatin immunoprecipitation results indicated that some MBW component genes are targets of GL2. We also showed that GL2 functions as a transcriptional repressor. Altogether, these results indicate that GL2 negatively regulates anthocyanin biosynthesis in Arabidopsis by directly repressing the expression of some MBW component genes.« less

Characterization of an activation-tagged mutant uncovers a role of GLABRA2 in anthocyanin biosynthesis in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiaoyu; Wang, Xianling; Hu, Qingnan

In Arabidopsis, anthocyanin biosynthesis is controlled by a MYB-bHLH-WD40 (MBW) transcriptional activator complex. The MBW complex activates the transcription of late biosynthesis genes in the flavonoid pathway, leading to the production of anthocyanins. A similar MBW complex regulates epidermal cell fate by activating the transcription of GLABRA2 (GL2), a homeodomain transcription factor required for trichome formation in shoots and non-hair cell formation in roots. Here we provide experimental evidence to show that GL2 also plays a role in regulating anthocyanin biosynthesis in Arabidopsis. From an activation-tagged mutagenized population of Arabidopsis plants, we isolated a dominant, gain-of-function mutant with reduced anthocyanins.more » Molecular cloning revealed that this phenotype is caused by an elevated expression of GL2, thus the mutant was named gl2-1D. Consistent with the view that GL2 acts as a negative regulator of anthocyanin biosynthesis, gl2-1D seedlings accumulated less whereas gl2-3 seedlings accumulated more anthocyanins in response to sucrose. Gene expression analysis indicated that expression of late, but not early, biosynthesis genes in the flavonoid pathway was dramatically reduced in gl2-1D but elevated in gl2-3 mutants. Further analysis showed that expression of some MBW component genes involved in the regulation of late biosynthesis genes was reduced in gl2-1D but elevated in gl2-3 mutants, and chromatin immunoprecipitation results indicated that some MBW component genes are targets of GL2. We also showed that GL2 functions as a transcriptional repressor. Altogether, these results indicate that GL2 negatively regulates anthocyanin biosynthesis in Arabidopsis by directly repressing the expression of some MBW component genes.« less

Differential Regulation of Multiple Steps in Inositol 1,4,5-Trisphosphate Signaling by Protein Kinase C Shapes Hormone-stimulated Ca2+ Oscillations*

PubMed Central

Bartlett, Paula J.; Metzger, Walson; Gaspers, Lawrence D.; Thomas, Andrew P.

2015-01-01

How Ca2+ oscillations are generated and fine-tuned to yield versatile downstream responses remains to be elucidated. In hepatocytes, G protein-coupled receptor-linked Ca2+ oscillations report signal strength via frequency, whereas Ca2+ spike amplitude and wave velocity remain constant. IP3 uncaging also triggers oscillatory Ca2+ release, but, in contrast to hormones, Ca2+ spike amplitude, width, and wave velocity were dependent on [IP3] and were not perturbed by phospholipase C (PLC) inhibition. These data indicate that oscillations elicited by IP3 uncaging are driven by the biphasic regulation of the IP3 receptor by Ca2+, and, unlike hormone-dependent responses, do not require PLC. Removal of extracellular Ca2+ did not perturb Ca2+ oscillations elicited by IP3 uncaging, indicating that reloading of endoplasmic reticulum stores via plasma membrane Ca2+ influx does not entrain the signal. Activation and inhibition of PKC attenuated hormone-induced Ca2+ oscillations but had no effect on Ca2+ increases induced by uncaging IP3. Importantly, PKC activation and inhibition differentially affected Ca2+ spike frequencies and kinetics. PKC activation amplifies negative feedback loops at the level of G protein-coupled receptor PLC activity and/or IP3 metabolism to attenuate IP3 levels and suppress the generation of Ca2+ oscillations. Inhibition of PKC relieves negative feedback regulation of IP3 accumulation and, thereby, shifts Ca2+ oscillations toward sustained responses or dramatically prolonged spikes. PKC down-regulation attenuates phenylephrine-induced Ca2+ wave velocity, whereas responses to IP3 uncaging are enhanced. The ability to assess Ca2+ responses in the absence of PLC activity indicates that IP3 receptor modulation by PKC regulates Ca2+ release and wave velocity. PMID:26078455

Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms

PubMed Central

Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

2014-01-01

Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities. PMID:25535553

Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms.

PubMed

Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

2014-09-01

Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.

A cotton Raf-like MAP3K gene, GhMAP3K40, mediates reduced tolerance to biotic and abiotic stress in Nicotiana benthamiana by negatively regulating growth and development.

PubMed

Chen, Xiaobo; Wang, Ji; Zhu, Ming; Jia, Haihong; Liu, Dongdong; Hao, Lili; Guo, Xingqi

2015-11-01

Mitogen-activated protein kinase (MAPK) cascades mediate various responses in plants. As the top component, MAP3Ks deserve more attention; however, little is known about the role of MAP3Ks, especially in cotton, a worldwide economic crop. In this study, a gene encoding a putative Raf-like MAP3K, GhMAP3K40, was isolated. GhMAP3K40 expression was induced by stress and multiple signal molecules. The plants overexpressing GhMAP3K40 had an enhanced tolerance to drought and salt stress at the germination stage. However, at the seedling stage, the transgenic plants suffered more severe damage after drought, exposure to pathogens and oxidative stress. The defence-related genes and the antioxidant system were activated in transgenic palnts, suggesting that GhMAP3K40 positively regulate the defence response. The transgenic plants were less able to prevent pathogenic invasion, which was due to defects in the cell structure of the leaves. The root system of the control plants were stronger compared with the transgenic plants. These results indicated a negative role of GhMAP3K40 in growth and development and GhMAP3K40 possibly caused the defects by down-regulating the lignin biosynthesis. Overall, these results suggest that GhMAP3K40 may positively regulate defence response but cause reduced tolerance to biotic and abiotic stress by negatively regulating growth and development. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

miR-30 Family Members Negatively Regulate Osteoblast Differentiation*

PubMed Central

Wu, Tingting; Zhou, Haibo; Hong, Yongfeng; Li, Jing; Jiang, Xinquan; Huang, Hui

2012-01-01

miRNAs are endogenously expressed 18- to 25-nucleotide RNAs that regulate gene expression through translational repression by binding to a target mRNA. Recently, it has been indicated that miRNAs are closely related to osteogenesis. Our previous data suggested that miR-30 family members might be important regulators during the biomineralization process. However, whether and how they modulate osteogenic differentiation have not been explored. In this study, we demonstrated that miR-30 family members negatively regulate BMP-2-induced osteoblast differentiation by targeting Smad1 and Runx2. Evidentially, overexpression of miR-30 family members led to a decrease of alkaline phosphatase activity, whereas knockdown of them increased the activity. Then bioinformatic analysis identified potential target sites of the miR-30 family located in the 3′ untranslated regions of Smad1 and Runx2. Western blot analysis and quantitative RT-PCR assays demonstrated that miR-30 family members inhibit Smad1 gene expression on the basis of repressing its translation. Furthermore, dual-luciferase reporter assays confirmed that Smad1 is a direct target of miR-30 family members. Rescue experiments that overexpress Smad1 and Runx2 significantly eliminated the inhibitory effect of miR-30 on osteogenic differentiation and provided strong evidence that miR-30 mediates the inhibition of osteogenesis by targeting Smad1 and Runx2. Also, the inhibitory effects of the miR-30 family were validated in mouse bone marrow mesenchymal stem cells. Therefore, our study uncovered that miR-30 family members are key negative regulators of BMP-2-mediated osteogenic differentiation. PMID:22253433

HMBA Enhances Prostratin-Induced Activation of Latent HIV-1 via Suppressing the Expression of Negative Feedback Regulator A20/TNFAIP3 in NF-κB Signaling.

PubMed

Chen, Duchu; Wang, Huiping; Aweya, Jude Juventus; Chen, Yanheng; Chen, Meihua; Wu, Xiaomeng; Chen, Xiaonan; Lu, Jing; Chen, Ruichuan; Liu, Min

2016-01-01

In the past decade, much emphasis has been put on the transcriptional activation of HIV-1, which is proposed as a promised strategy for eradicating latent HIV-1 provirus. Two drugs, prostratin and hexamethylene bisacetamide (HMBA), have shown potent effects as inducers for releasing HIV-1 latency when used alone or in combination, although their cellular target(s) are currently not well understood, especially under drug combination. Here, we have shown that HMBA and prostratin synergistically release HIV-1 latency via different mechanisms. While prostratin strongly stimulates HMBA-induced HIV-1 transcription via improved P-TEFb activation, HMBA is capable of boosting NF-κB-dependent transcription initiation by suppressing prostratin-induced expression of the deubiquitinase A20, a negative feedback regulator in the NF-κB signaling pathway. In addition, HMBA was able to increase prostratin-induced phosphorylation and degradation of NF-κB inhibitor IκBα, thereby enhancing and prolonging prostratin-induced nuclear translocation of NF-κB, a prerequisite for stimulation of transcription initiation. Thus, by blocking the negative feedback circuit, HMBA functions as a signaling enhancer of the NF-κB signaling pathway.

Tracing How Normative Messages May Influence Physical Activity Intention.

PubMed

van Bavel, René; Esposito, Gabriele; Baranowski, Tom; Duch-Brown, Néstor

2017-04-01

Normative messages have been shown to increase intention to do physical activity. We traced how "positive" and "negative" normative messages influenced physical activity intention by comparing constructs of the model of goal-directed behavior with descriptive norms (MGDB + DNs) across control and treatment groups in an experiment. For this purpose, 16-24-year-old respondents (n = 1,200) in Bulgaria, Croatia, and Romania were asked about their age, sex, and levels of physical activity before being exposed to positive and negative normative messages and completing a questionnaire with MGDB + DNs scales. Different MGDB + DNs constructs were influenced by the normative messages: compared with the control, the negative message group showed stronger attitudes (p = .003) and the positive message group showed higher positive anticipated emotions (p = .005). The positive message's effect is consistent with the literature on conformity to social norms. The negative message's effect lends itself to interpretations based on social identity and deviance regulation theories.

NHERF1 inhibits proliferation of triple-negative breast cancer cells by suppressing GPER signaling.

PubMed

Wang, Yan; Peng, Zhiqiang; Meng, Ran; Tao, Tao; Wang, Qiqi; Zhao, Chunjuan; Liu, Hua; Song, Ran; Zheng, Junfang; Qin, Qiong; He, Junqi

2017-07-01

G protein-coupled estrogen receptor (GPER) signaling is activated in triple-negative breast cancer (TNBC); however, the detailed mechanisms of its regulation remain unclear. The present study aimed to elucidate the molecular mechanisms involved in GPER activation in TNBC. In MDA-MB-231 cells, a TNBC cell line, NHERF1 interaction with GPER was verified by co-immunoprecipitation and immunofluorescent staining assays. Overexpression of NHERF1 in MDA-MB-231 cells inhibited GPER-mediated proliferation and phosphorylation of ERK1/2 and Akt. Furthermore, NHERF1 expression levels were negatively correlated with the gene signatures of GPER activation, ERK1/2 and Akt signaling, and cell proliferation in early stage of TNBC tumors from the TCGA data set. Taken together, NHERF1 inhibited the activation of GPER-mediated signaling and suppressed the proliferation of triple-negative breast cancer cells. Loss of NHERF1 expression may play a pivotal role in the early stage of TNBC carcinogenesis.

Degradation of the HilC and HilD regulator proteins by ATP-dependent Lon protease leads to downregulation of Salmonella pathogenicity island 1 gene expression.

PubMed

Takaya, Akiko; Kubota, Yohsuke; Isogai, Emiko; Yamamoto, Tomoko

2005-02-01

Salmonella pathogenicity island 1 (SPI1) enables infecting Salmonella to cross the small intestinal barrier and to escape phagocytosis by inducing apoptosis. Several environmental signals and transcriptional regulators modulate the expression of hilA, which encodes a protein playing a central role in the regulatory hierarchy of SPI1 gene expression. We have previously shown that Lon, a stress-induced ATP-dependent protease, is a negative regulator of hilA, suggesting that it targets factors required for activating hilA expression. To elucidate the mechanisms by which Lon protease negatively regulates SPI1 transcription, we looked for its substrate proteins. We found that HilC and HilD, which are positive regulators of hilA expression, accumulate in Lon-depleted cells, and that the enhancement of SPI1 expression that occurs in a lon-disrupted mutant is not observed in the lon hilC hilD triple null mutant. Furthermore, we demonstrated that the half-lives of HilC and HilD are, respectively, about 12 times and three times longer in the Lon-depleted mutant, than in the Lon+ cells, suggesting that Lon targets both of HilC and HilD. In view of these findings, we suggest that the regulation of SPI1 expression is negatively controlled through degradation of the HilC and HilD transcriptional regulators by Lon.

PUB1 Interacts with the Receptor Kinase DMI2 and Negatively Regulates Rhizobial and Arbuscular Mycorrhizal Symbioses through Its Ubiquitination Activity in Medicago truncatula.

PubMed

Vernié, Tatiana; Camut, Sylvie; Camps, Céline; Rembliere, Céline; de Carvalho-Niebel, Fernanda; Mbengue, Malick; Timmers, Ton; Gasciolli, Virginie; Thompson, Richard; le Signor, Christine; Lefebvre, Benoit; Cullimore, Julie; Hervé, Christine

2016-04-01

PUB1, an E3 ubiquitin ligase, which interacts with and is phosphorylated by the LYK3 symbiotic receptor kinase, negatively regulates rhizobial infection and nodulation during the nitrogen-fixing root nodule symbiosis in Medicago truncatula In this study, we show that PUB1 also interacts with and is phosphorylated by DOES NOT MAKE INFECTIONS 2, the key symbiotic receptor kinase of the common symbiosis signaling pathway, required for both the rhizobial and the arbuscular mycorrhizal (AM) endosymbioses. We also show here that PUB1 expression is activated during successive stages of root colonization by Rhizophagus irregularis that is compatible with its interaction with DOES NOT MAKE INFECTIONS 2. Through characterization of a mutant, pub1-1, affected by the E3 ubiquitin ligase activity of PUB1, we have shown that the ubiquitination activity of PUB1 is required to negatively modulate successive stages of infection and development of rhizobial and AM symbioses. In conclusion, PUB1 represents, to our knowledge, a novel common component of symbiotic signaling integrating signal perception through interaction with and phosphorylation by two key symbiotic receptor kinases, and downstream signaling via its ubiquitination activity to fine-tune both rhizobial and AM root endosymbioses. © 2016 American Society of Plant Biologists. All Rights Reserved.

Role of Fatty Acid Kinase in Cellular Lipid Homeostasis and SaeRS-Dependent Virulence Factor Expression in Staphylococcus aureus

PubMed Central

Ericson, Megan E.; Subramanian, Chitra; Frank, Matthew W.

2017-01-01

ABSTRACT The SaeRS two-component system is a master activator of virulence factor transcription in Staphylococcus aureus, but the cellular factors that control its activity are unknown. Fatty acid (FA) kinase is a two-component enzyme system required for extracellular FA uptake and SaeRS activity. Here, we demonstrate the existence of an intracellular nonesterified FA pool in S. aureus that is elevated in strains lacking FA kinase activity. SaeRS-mediated transcription is restored in FA kinase-negative strains when the intracellular FA pool is reduced either by growth with FA-depleted bovine serum albumin to extract the FA into the medium or by the heterologous expression of Neisseria gonorrhoeae acyl-acyl carrier protein synthetase to activate FA for phospholipid synthesis. These data show that FAs act as negative regulators of SaeRS signaling, and FA kinase activates SaeRS-dependent virulence factor production by lowering inhibitory FA levels. Thus, FA kinase plays a role in cellular lipid homeostasis by activating FA for incorporation into phospholipid, and it indirectly regulates SaeRS signaling by maintaining a low intracellular FA pool. PMID:28765222

Tetraspanin 6 (TSPAN6) Negatively Regulates Retinoic Acid-inducible Gene I-like Receptor-mediated Immune Signaling in a Ubiquitination-dependent Manner*

PubMed Central

Wang, Yetao; Tong, Xiaomei; Omoregie, Ehimwenma Sheena; Liu, Wenjun; Meng, Songdong; Ye, Xin

2012-01-01

The recognition between retinoic acid-inducible gene I-like receptors (RLRs) and viral RNA triggers an intracellular cascade of signaling to induce the expression of type I IFNs. Both positive and negative regulation of the RLR signaling pathway are important for the host antiviral immune response. Here, we demonstrate that the tetraspanin protein TSPAN6 inhibits RLR signaling by affecting the formation of the adaptor MAVS (mitochondrial antiviral signaling)-centered signalosome. We found that overexpression of TSPAN6 impaired RLR-mediated activation of IFN-stimulated response element, NF-κB, and IFN-β promoters, whereas knockdown of TSPAN6 enhanced the RLR-mediated signaling pathway. Interestingly, as the RLR pathway was activated, TSPAN6 underwent Lys-63-linked ubiquitination, which promoted its association with MAVS. The interaction of TSPAN6 and MAVS interfered with the recruitment of RLR downstream molecules TRAF3, MITA, and IRF3 to MAVS. Further study revealed that the first transmembrane domain of TSPAN6 is critical for its ubiquitination and association with MAVS as well as its inhibitory effect on RLR signaling. We concluded that TSPAN6 functions as a negative regulator of the RLR pathway by interacting with MAVS in a ubiquitination-dependent manner. PMID:22908223

The association between physical activity and eating self-regulation in overweight and obese women.

PubMed

Carraça, Eliana V; Silva, Marlene N; Coutinho, Sílvia R; Vieira, Paulo N; Minderico, Cláudia S; Sardinha, Luís B; Teixeira, Pedro J

2013-01-01

Successful weight management relies heavily on eating and exercise behaviors. However, little is known about the association between both on a psychosocial level. This study examined the relationship between exercise and eating regulation by exploring the mediating effects of negative body image investment and depressive mood, and their stability through time. Analyses were conducted at two different moments (12 and 36 months), involving a sample of 221 overweight/obese women (age: 37.6 ± 7 years; BMI: 31.6 ± 4.1 kg/m(2)) that participated in a behavioral weight control intervention. Bivariate correlations and mediation analyses using Preacher & Hayes resampling procedures were conducted. At 12 months, negative body image investment was the only significant mediator of the exercise-eating relationship. This variable explained larger portions of the indirect effects of structured rather than lifestyle exercise on eating. At 36 months, negative investment and to a lesser extent depressive mood partially explained the exercise-eating association. Our findings suggest that, besides physiological effects of exercise, psychological mechanisms related to body image and mood also explain the role of physical activity as a 'gateway behavior' for improved eating regulation in overweight women. These effects appear to be stable and may help understand the key role of exercise in long-term weight management.

Beyond Symmetry Breaking: Competition and Negative Feedback in GTPase regulation

PubMed Central

Wu, Chi-Fang; Lew, Daniel J.

2013-01-01

Summary Cortical domains are often specified by the local accumulation of active GTPases. Such domains can arise through spontaneous symmetry breaking, suggesting that GTPase accumulation occurs via positive feedback. Here, we focus on recent advances in fungal and plant cell models, where new work suggests that polarity-controlling GTPases develop only one “front” because GTPase clusters engage in a winner-takes-all competition. However, in some circumstances two or more GTPase domains can co-exist, and the basis for the switch from competition to coexistence remains an open question. Polarity GTPases can undergo oscillatory clustering and dispersal, suggesting that these systems contain negative feedback. Negative feedback may prevent polarity clusters from spreading too far, regulate the balance between competition and co-existence, and provide directional flexibility for cells tracking gradients. PMID:23731999

Clarifying beliefs underlying hunter intentions to support a ban on lead shot

USGS Publications Warehouse

Schroeder, Susan A.; Fulton, David C.; Doncarlos, Kathy

2016-01-01

Shot from hunting adds toxic lead to environments worldwide. Existing lead shot regulations have been instituted with little understanding of hunter beliefs and attitudes. This study applied the Theory of Reasoned Action, using a multilevel, multivariate approach, to clarify how positive and negative beliefs relate to attitudes about a ban on lead shot. Structure coefficients and commonality analysis were employed to further examine relationships between beliefs and attitudes. Results suggest that while both positive and negative outcomes influence attitudes, positive outcomes were more influential for supporters and negative beliefs for opposers. Management may need to focus on the results from hunters who indicated that they would be unlikely to support a ban, as these hunters include those who may actively oppose additional efforts to regulate lead.

Behavioral impact of neurotransmitter-activated GPCRs: Muscarinic and GABAB receptors regulate C. elegans locomotion

PubMed Central

Dittman, Jeremy S; Kaplan, Joshua M

2008-01-01

Neurotransmitter released from presynaptic terminals activates both ligand-gated ion channels (ionotropic receptors) and a variety of G protein-coupled receptors (GPCRs). These neurotransmitter receptors are expressed on both pre- and postsynaptic cells. Thus, each neurotransmitter acts on multiple receptor classes, generating a large repertoire of physiological responses. The impact of many ionotropic receptors on neuronal activity and behavior has been clearly elucidated; however, much less is known about how neurotransmitter-gated GPCRs regulate neurons and circuits. In C. elegans, both Acetylcholine (ACh) and GABA are released in the nerve cord and mediate fast neuromuscular excitation and inhibition during locomotion. Here we identify a muscarinic receptor (GAR-2) and the GABAB receptor dimer (GBB-1/2) that detect synaptically released ACh and GABA, respectively. Both GAR-2 and GBB-1/2 inhibited cholinergic motor neurons when ACh and GABA levels were enhanced. Loss of either GPCR resulted in movement defects, suggesting that these receptors are activated during locomotion. When the negative feedback provided by GAR-2 was replaced with positive feedback, animals became highly sensitive to ACh levels and locomotion was severely impaired. Thus, conserved GPCRs act in the nematode motor circuit to provide negative feedback and to regulate locomotory behaviors that underlie navigation. PMID:18614679

Frontal EEG and emotion regulation: electrocortical activity in response to emotional film clips is associated with reduced mood induction and attention interference effects.

PubMed

Dennis, Tracy A; Solomon, Beylul

2010-12-01

Frontal EEG activity is thought to reflect affective dispositions, but may also reflect the emotional demands of a specific context combined with the capability to regulate emotions in that context. The present study examined this hypothesis by testing whether frontal EEG activity during mood inductions versus a resting baseline predicted emotion regulation. EEG was recorded while participants (N=66, 40 females) received a fearful, sad, or neutral mood induction. Emotion regulation was measured following the mood inductions as self-reported change in negative mood and as attention interference in a task with mood-congruent emotional distracters. Greater frontal EEG activity during the mood inductions versus baseline was associated with more effective emotion regulation: less post-induction sadness and anxiety and reduced mood-congruent attention interference effects. Effects did not differ between the left and right hemispheres. Results support the hypothesis that frontal EEG activity reflects both emotional context and emotion-regulatory capabilities. Copyright © 2010 Elsevier B.V. All rights reserved.

PIF4 and PIF5 transcription factors link blue light and auxin to regulate the phototropic response in Arabidopsis.

PubMed

Sun, Jiaqiang; Qi, Linlin; Li, Yanan; Zhai, Qingzhe; Li, Chuanyou

2013-06-01

Both blue light (BL) and auxin are essential for phototropism in Arabidopsis thaliana. However, the mechanisms by which light is molecularly linked to auxin during phototropism remain elusive. Here, we report that phytochrome interacting factoR4 (PIF4) and PIF5 act downstream of the BL sensor phototropin1 (PHOT1) to negatively modulate phototropism in Arabidopsis. We also reveal that PIF4 and PIF5 negatively regulate auxin signaling. Furthermore, we demonstrate that PIF4 directly activates the expression of the auxin/indole-3-acetic acid (IAA) genes IAA19 and IAA29 by binding to the G-box (CACGTG) motifs in their promoters. Our genetic assays demonstrate that IAA19 and IAA29, which physically interact with auxin response factor7 (ARF7), are sufficient for PIF4 to negatively regulate auxin signaling and phototropism. This study identifies a key step of phototropic signaling in Arabidopsis by showing that PIF4 and PIF5 link light and auxin.

Neural Correlates of the Use of Psychological Distancing to Regulate Responses to Negative Social Cues: A Study of Patients with Borderline Personality Disorder

PubMed Central

Koenigsberg, Harold W.; Fan, Jin; Ochsner, Kevin; Liu, Xun; Guise, Kevin G.; Pizzarello, Scott; Dorantes, Christine; Guerreri, Stephanie; Tecuta, Lucia; Goodman, Marianne; New, Antonia; Siever, Larry J

2009-01-01

Background Emotional instability is a defining feature of borderline personality disorder (BPD), yet little is understood about its underlying neural correlates. One possible contributing factor to emotional instability is a failure to adequately employ adaptive cognitive regulatory strategies such as psychological distancing. Method To determine whether there are differences in neural dynamics underlying this control strategy, between BPD patients and healthy volunteers (HC’s), BOLD fMRI signals were acquired as 18 BPD and 16 HC subjects distanced from or simply looked at negative and neutral pictures depicting social interactions. Contrasts in signal between distance and look condition were compared between groups to identify commonalities and differences in regional activation. Results BPD patients show a different pattern of activation compared to HC subjects when looking at negative vs. neutral pictures. When distancing vs. looking at negative pictures, both groups showed decreased negative affect in rating and increased activation of the dorsolateral prefrontal cortex, areas near/along the intraparietal sulcus (IPS), ventrolateral prefrontal cortex and posterior cingulate/precuneus regions. However, the BPD group showed less BOLD signal change in dorsal anterior cingulate cortex and IPS, less deactivation in the amygdala and greater activation in the superior temporal sulcus and superior frontal gyrus. Conclusion BPD and HC subjects display different neural dynamics while passively viewing social emotional stimuli. In addition, BPD patients do not engage the cognitive control regions to the extent that HC’s do when employing a distancing strategy to regulate emotional reactions, which may be a factor contributing to the affective instability of BPD. PMID:19651401

State-Dependent Differences in Emotion Regulation Between Unmedicated Bipolar Disorder and Major Depressive Disorder.

PubMed

Rive, Maria M; Mocking, Roel J T; Koeter, Maarten W J; van Wingen, Guido; de Wit, Stella J; van den Heuvel, Odile A; Veltman, Dick J; Ruhé, Henricus G; Schene, Aart H

2015-07-01

Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD and BD. Better insight into these differences would be helpful for differentiation based on disorder-specific underlying pathophysiological mechanisms. Previous studies comparing these disorders often allowed medication use, limiting generalizability and validity. Moreover, patients with MDD and BD were mostly compared during the depressed, but not the remitted, state, while state might potentially modulate differences between MDD and BD. To investigate positive and negative emotion regulation in medication-free patients with MDD and BD in 2 mood states: depressed or remitted. A cross-sectional study conducted from May 2009 to August 2013 comparing behavioral and functional magnetic resonance imaging emotion regulation data of 42 patients with MDD, 35 with BD, and 36 healthy control (HC) participants free of psychotropic medication recruited from several psychiatric institutions across the Netherlands. A voluntary emotion regulation functional magnetic resonance imaging task using positive and negative pictures. Behavioral and functional magnetic resonance imaging blood oxygen level-dependent responses during emotion regulation. In the remitted state, only patients with BD showed impaired emotion regulation (t = 3.39; P < .001; Cohen d = 0.70), irrespective of emotion type and associated with increased dorsolateral prefrontal cortex activity compared with those with MDD and healthy control participants (P = .008). In the depressed state, patients with MDD and BD differed with regard to happy vs sad emotion regulation (t = 4.19; P < .001; Cohen d = 1.66) associated with differences in rostral anterior cingulate activity (P < .001). Patients with MDD regulated sad and happy emotions poorly compared with those with BD and healthy control participants, while they demonstrated no rostral anterior cingulate difference between happy and sad emotion regulation. In contrast, patients with BD performed worse than those with MDD on sad emotion regulation but normal on happy emotion regulation, and they demonstrated significantly less rostral anterior cingulate activity while regulating happy compared with sad emotions. Medication-free patients with MDD vs BD appear to differ in brain activations during emotion regulation, both while depressed and in remission. These different neuropathophysiological mechanisms between MDD and BD may be useful for further development of additional diagnostic tools.

Dynamic control of type I IFN signalling by an integrated network of negative regulators.

PubMed

Porritt, Rebecca A; Hertzog, Paul J

2015-03-01

Whereas type I interferons (IFNs) have critical roles in protection from pathogens, excessive IFN responses contribute to pathology in both acute and chronic settings, pointing to the importance of balancing activating signals with regulatory mechanisms that appropriately tune the response. Here we review evidence for an integrated network of negative regulators of IFN production and action, which function at all levels of the activating and effector signalling pathways. We propose that the aim of this extensive network is to limit tissue damage while enabling an IFN response that is temporally appropriate and of sufficient magnitude. Understanding the architecture and dynamics of this network, and how it differs in distinct tissues, will provide new insights into IFN biology and aid the design of more effective therapeutics. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Motivations for health and their associations with lifestyle, work style, health, vitality, and employee productivity.

PubMed

van Scheppingen, Arjella R; de Vroome, Ernest M M; ten Have, Kristin C J M; Zwetsloot, Gerard I J M; Bos, Ellen H; van Mechelen, Willem

2014-05-01

Investigate employees' underlying motivational regulatory styles toward healthy living and their associations with lifestyle, work style, health, vitality, and productivity. Regression analyses on cross-sectional data from Dutch employees (n = 629), obtained as baseline measurement before a workplace health promotion project. Controlled regulation was not associated with smoking and alcohol use, and negatively associated with physical activity, healthy dietary habits, relaxation, and a balanced work style. Autonomous regulation was positively associated with physical activity, healthy dietary habits, and relaxation, and negatively associated with smoking and alcohol use. Healthy lifestyle and work style were associated with perceived health and vitality, which in turn were associated with employees' productivity (absenteeism and presenteeism). Internalization of the value of health is important to promote a healthy lifestyle and work style among employees, and has meaningful business implications.

The Btk-dependent PIP5K1γ lipid kinase activation by Fas counteracts FasL-induced cell death.

PubMed

Rossin, Aurélie; Lounnas, Nadia; Durivault, Jérôme; Miloro, Giorgia; Gagnoux-Palacios, Laurent; Hueber, Anne-Odile

2017-11-01

The Fas/FasL system plays a critical role in death by apoptosis and immune escape of cancer cells. The Fas receptor being ubiquitously expressed in tissues, its apoptotic-inducing function, initiated upon FasL binding, is tightly regulated by several negative regulatory mechanisms to prevent inappropriate cell death. One of them, involving the non-receptor tyrosine kinase Btk, was reported mainly in B cells and only poorly described. We report here that Btk negatively regulates, through its tyrosine kinase activity, the FasL-mediated cell death in epithelial cell lines from colon cancer origin. More importantly, we show that Btk interacts not only with Fas but also with the phosphatidylinositol-4-phosphate 5-kinase, PIP5K1γ, which, upon stimulation by Fas ligand, is responsible of a rapid and transient synthesis of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P 2 ). This production requires both the presence and the tyrosine kinase activity of Btk, and participates in the negative regulation of FasL-mediated cell death since knocking down PIP5K1γ expression significantly strengthens the apoptotic signal upon FasL engagement. Altogether, our data demonstrate the cooperative role of Btk and PIP5K1γ in a FasL-induced PI(4,5)P 2 production, both proteins participating to the threshold setting of FasL-induced apoptotic commitment in colorectal cell lines.

Dopamine Synthesis and D3 Receptor Activation in Pancreatic β-Cells Regulates Insulin Secretion and Intracellular [Ca2+] Oscillations

PubMed Central

Ustione, Alessandro

2012-01-01

Pancreatic islets are critical for glucose homeostasis via the regulated secretion of insulin and other hormones. We propose a novel mechanism that regulates insulin secretion from β-cells within mouse pancreatic islets: a dopaminergic negative feedback acting on insulin secretion. We show that islets are a site of dopamine synthesis and accumulation outside the central nervous system. We show that both dopamine and its precursor l-dopa inhibit glucose-stimulated insulin secretion, and this inhibition correlates with a reduction in frequency of the intracellular [Ca2+] oscillations. We further show that the effects of dopamine are abolished by a specific antagonist of the dopamine receptor D3. Because the dopamine transporter and dopamine receptors are expressed in the islets, we propose that cosecretion of dopamine with insulin activates receptors on the β-cell surface. D3 receptor activation results in changes in intracellular [Ca2+] dynamics, which, in turn, lead to lowered insulin secretion. Because blocking dopaminergic negative feedback increases insulin secretion, expanding the knowledge of this pathway in β-cells might offer a potential new target for the treatment of type 2 diabetes. PMID:22918877

Ethylene Mediates Alkaline-Induced Rice Growth Inhibition by Negatively Regulating Plasma Membrane H+-ATPase Activity in Roots

PubMed Central

Chen, Haifei; Zhang, Quan; Cai, Hongmei; Xu, Fangsen

2017-01-01

pH is an important factor regulating plant growth. Here, we found that rice was better adapted to low pH than alkaline conditions, as its growth was severely inhibited at high pH, with shorter root length and an extreme biomass reduction. Under alkaline stress, the expression of genes for ethylene biosynthesis enzymes in rice roots was strongly induced by high pH and exogenous ethylene precursor ACC and ethylene overproduction in etol1-1 mutant aggravated the alkaline stress-mediated inhibition of rice growth, especially for the root elongation with decreased cell length in root apical regions. Conversely, the ethylene perception antagonist silver (Ag+) and ein2-1 mutants could partly alleviate the alkaline-induced root elongation inhibition. The H+-ATPase activity was extremely inhibited by alkaline stress and exogenous ACC. However, the H+-ATPase-mediated rhizosphere acidification was enhanced by exogenous Ag+, while H+ efflux on the root surface was extremely inhibited by exogenous ACC, suggesting that ethylene negatively regulated H+-ATPase activity under high-pH stress. Our results demonstrate that H+-ATPase is involved in ethylene-mediated inhibition of rice growth under alkaline stress. PMID:29114258

Effects of c-Jun N-terminal kinase on Activin A/Smads signaling in PC12 cell suffered from oxygen-glucose deprivation.

PubMed

Wang, J Q; Xu, Z H; Liang, W Z; He, J T; Cui, Y; Liu, H Y; Xue, L X; Shi, W; Shao, Y K; Mang, J; Xu, Z X

2016-02-29

Activin A (Act A), a member of transforming growth factor-β (TGF-β) superfamily, is an early gene in response to cerebral ischemia. Growing evidences confirm the neuroprotective effect of Act A in ischemic injury through Act A/Smads signal activation. In this process, regulation networks are involved in modulating the outcomes of Smads signaling. Among these regulators, crosstalk between c-Jun N-terminal kinase (JNK) and Smads signaling has been found in the TGF-β induced epithelial-mesenchymal transition. However, in neural ischemia, the speculative regulation between JNK and Act A/Smads signaling pathways has not been clarified. To explore this issue, an Oxygen Glucose Deprivation (OGD) model was introduced to nerve-like PC12 cells. We found that JNK signal activation occurred at the early time of OGD injury (1 h). Act A administration suppressed JNK phosphorylation. In addition, JNK inhibition could elevate the strength of Smads signaling and attenuate neural apoptosis after OGD injury. Our results indicated a negative regulation effect of JNK on Smads signaling in ischemic injury. Taken together, JNK, as a critical site for neural apoptosis and negative regulator for Act A/Smads signaling, was presumed to be a molecular therapeutic target for ischemia.

Lead/acid battery design and operation

NASA Astrophysics Data System (ADS)

Manders, J. E.; Bui, N.; Lambert, D. W. H.; Navarette, J.; Nelson, R. F.; Valeriote, E. M.

In keeping with the tradition of previous meetings, the Seventh Asian Battery Conference closed with the delegates putting questions to an expert panel of battery scientists and technologies. The proceedings were lively and the subjects were as follows. Grid alloys: gassing characteristics; influence of minor constituents on metallurgical and electrochemical characteristics; latest trends in composition; alloys for cast-on straps. Battery manufacture and operation: plate formation ( α-PbO 2: β-PbO 2 ratio); dendritic shorts. Separators: contribution to battery internal resistance; influence of negative-plate enveloping; reduced backweb. Valve-regulated lead/acid batteries: positive active-material: negative active-material ratio; hydrogen evolution and dry-out; negative-plate self-discharge; tank vs. box formation.

Genetics of the Blue Light-Dependent Signal Cascade That Controls Phototaxis in the Cyanobacterium Synechocystis sp. PCC6803.

PubMed

Sugimoto, Yuki; Nakamura, Hiroshi; Ren, Shukun; Hori, Koichi; Masuda, Shinji

2017-03-01

The Synechocystis sp. PCC6803 can move on a solid surface in response to light, a phenomenon called phototaxis. Although many of the photoreceptors involved in phototaxis have been identified, the mechanisms that regulate directional motility of Synechocystis are not well understood. Previous studies showed that a mutant lacking the blue light-using flavin (BLUF) photoreceptor PixD exhibits negative phototaxis under conditions where the wild type responds positively. PixD interacts with the pseudo-response regulator-like protein PixE in a light-dependent manner, suggesting that this intermolecular interaction is important for phototaxis regulation, although genetic evidence has been lacking. To gain further insight into phototaxis regulation by PixD-PixE signaling, we constructed the deletion mutants ΔPixE and ΔPixD-ΔPixE, and characterized their phenotypes, which matched those of the wild type (positive phototaxis). Because ΔPixD exhibited negative phototaxis, PixE must function downstream of PixD. Under intense blue light (>100 μmol m-2 s-1; 470 nm) the wild type exhibited negative phototaxis, but ΔPixD-PixE exhibited positive phototaxis toward low-intensity blue light (∼0.8 μmol m-2 s-1; 470 nm). These results suggest that an unknown light-sensing system(s), that is necessary for directional cell movement, can be activated by low-intensity blue light; on the other hand, PixD needs high-intensity blue light to be activated. We also isolated spontaneous mutants that compensated for the pixE deletion. Genome-wide sequencing of the mutants revealed that the uncharacterized gene sll2003 regulates positive and negative phototaxis in response to light intensity. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Appraisals to affect: Testing the integrative cognitive model of bipolar disorder.

PubMed

Palmier-Claus, Jasper E; Dodd, Alyson; Tai, Sara; Emsley, Richard; Mansell, Warren

2016-09-01

Cognitive models have suggested that extreme appraisals of affective states and maladaptive affect regulation strategies are important in the development of bipolar symptomatology. Little is known about the pathway by which these appraisals and behaviours interact in the formation of activated and depressed affective states. This study tested the predictions that (1) ascent behaviours mediate the relationship between positive appraisals of activated mood and activation; and (2) descent behaviours mediate the relationship between negative appraisals of activated mood and depression. A total of 52 individuals with a DSM-IV diagnosis of bipolar I or II disorder (confirmed by structured interview) completed biweekly assessments of affect regulation behaviours and mood for 4 weeks. Positive and negative appraisals of affective states were assessed at baseline through the Hypomanic Attitudes and Positive Prediction Inventory. Multilevel mediation analysis was used to explore the data. Ascent behaviours partially mediated the relationship between positive appraisals of activated mood and activation. Descent behaviours, but not negative appraisals of activated mood, predicted levels of depression indicating the absence of a mediation effect. The results suggest that positive appraisals of activated mood can escalate activation in individuals with bipolar disorder. Such appraisals may be inherently rewarding and reinforcing directly elevating levels of activation, whilst increasing individuals' use of ascent behaviours. The results are consistent with the view that appraisals and behaviours should be targeted during cognitive behavioural therapy for bipolar disorder. It may be beneficial to target positive appraisals of activated mood in cognitive behavioural therapy for mania. Cognitive behavioural therapists may also wish to focus on identifying and targeting individuals' use of ascent behaviours to reduce highly activated states. © 2015 The British Psychological Society.

CYTOKININ OXIDASE/DEHYDROGENASE3 Maintains Cytokinin Homeostasis during Root and Nodule Development in Lotus japonicus1[OPEN

PubMed Central

Heckmann, Anne B.; Kelly, Simon

2016-01-01

Cytokinins are required for symbiotic nodule development in legumes, and cytokinin signaling responses occur locally in nodule primordia and in developing nodules. Here, we show that the Lotus japonicus Ckx3 cytokinin oxidase/dehydrogenase gene is induced by Nod factor during the early phase of nodule initiation. At the cellular level, pCkx3::YFP reporter-gene studies revealed that the Ckx3 promoter is active during the first cortical cell divisions of the nodule primordium and in growing nodules. Cytokinin measurements in ckx3 mutants confirmed that CKX3 activity negatively regulates root cytokinin levels. Particularly, tZ and DHZ type cytokinins in both inoculated and uninoculated roots were elevated in ckx3 mutants, suggesting that these are targets for degradation by the CKX3 cytokinin oxidase/dehydrogenase. The effect of CKX3 on the positive and negative roles of cytokinin in nodule development, infection and regulation was further clarified using ckx3 insertion mutants. Phenotypic analysis indicated that ckx3 mutants have reduced nodulation, infection thread formation and root growth. We also identify a role for cytokinin in regulating nodulation and nitrogen fixation in response to nitrate as ckx3 phenotypes are exaggerated at increased nitrate levels. Together, these findings show that cytokinin accumulation is tightly regulated during nodulation in order to balance the requirement for cell divisions with negative regulatory effects of cytokinin on infection events and root development. PMID:26644503

Insulin Activates RSK (p90 Ribosomal S6 Kinase) to Trigger a New Negative Feedback Loop That Regulates Insulin Signaling for Glucose Metabolism*

PubMed Central

Smadja-Lamère, Nicolas; Shum, Michael; Déléris, Paul; Roux, Philippe P.; Abe, Jun-Ichi; Marette, André

2013-01-01

We previously demonstrated that the mTORC1/S6K1 pathway is activated by insulin and nutrient overload (e.g. amino acids (AA)), which leads to the inhibition of the PI3K/Akt pathway via the inhibitory serine phosphorylation of IRS-1, notably on serine 1101 (Ser-1101). However, even in the absence of AA, insulin can still promote IRS-1 Ser-1101 phosphorylation by other kinases that remain to be fully characterized. Here, we describe a new negative regulator of IRS-1, the p90 ribosomal S6 kinase (RSK). Computational analyses revealed that Ser-1101 within IRS-1 falls into the consensus motif of RSK. Moreover, recombinant RSK phosphorylated IRS-1 C-terminal fragment on Ser-1101, which was prevented by mutations of this site or when a kinase-inactive mutant of RSK was used. Using antibodies directed toward the phosphorylation sites located in the activation segment of RSK (Ser-221 or Ser-380), we found that insulin activates RSK in L6 myocytes in the absence of AA overload. Inhibition of RSK using either the pharmacological inhibitor BI-D1870 or after adenoviral expression of a dominant negative RSK1 mutant (RSK1-DN) showed that RSK selectively phosphorylates IRS-1 on Ser-1101. Accordingly, expression of the RSK1-DN mutant in L6 myocytes and FAO hepatic cells improved insulin action on glucose uptake and glucose production, respectively. Furthermore, RSK1 inhibition prevented insulin resistance in L6 myocytes chronically exposed to high glucose and high insulin. These results show that RSK is a novel regulator of insulin signaling and glucose metabolism and a potential mediator of insulin resistance, notably through the negative phosphorylation of IRS-1 on Ser-1101. PMID:24036112

EDS1 contributes to nonhost resistance of Arabidopsis thaliana against Erwinia amylovora.

PubMed

Moreau, Manon; Degrave, Alexandre; Vedel, Régine; Bitton, Frédérique; Patrit, Oriane; Renou, Jean-Pierre; Barny, Marie-Anne; Fagard, Mathilde

2012-03-01

Erwinia amylovora causes fire blight in rosaceous plants. In nonhost Arabidopsis thaliana, E. amylovora triggers necrotic symptoms associated with transient bacterial multiplication, suggesting either that A. thaliana lacks a susceptibility factor or that it actively restricts E. amylovora growth. Inhibiting plant protein synthesis at the time of infection led to an increase in necrosis and bacterial multiplication and reduced callose deposition, indicating that A. thaliana requires active protein synthesis to restrict E. amylovora growth. Analysis of the callose synthase-deficient pmr4-1 mutant indicated that lack of callose deposition alone did not lead to increased sensitivity to E. amylovora. Transcriptome analysis revealed that approximately 20% of the genes induced following E. amylovora infection are related to defense and signaling. Analysis of mutants affected in NDR1 and EDS1, two main components of the defense-gene activation observed, revealed that E. amylovora multiplied ten times more in the eds1-2 mutant than in the wild type but not in the ndr1-1 mutant. Analysis of mutants affected in three WRKY transcription factors showing EDS1-dependent activation identified WRKY46 and WRKY54 as positive regulators and WRKY70 as a negative regulator of defense against E. amylovora. Altogether, we show that EDS1 is a positive regulator of nonhost resistance against E. amylovora in A. thaliana and hypothesize that it controls the production of several effective defenses against E. amylovora through the action of WRKY46 and WRKY54, while WRKY70 acts as a negative regulator.

DYRK1A is a novel negative regulator of cardiomyocyte hypertrophy.

PubMed

Kuhn, Christian; Frank, Derk; Will, Rainer; Jaschinski, Christoph; Frauen, Robert; Katus, Hugo A; Frey, Norbert

2009-06-19

Activation of the phosphatase calcineurin and its downstream targets, transcription factors of the NFAT family, results in cardiomyocyte hypertrophy. Recently, it has been shown that the dual specificity tyrosine (Y) phosphorylation-regulated kinase 1A (DYRK1A) is able to antagonize calcineurin signaling by directly phosphorylating NFATs. We thus hypothesized that DYRK1A might modulate the hypertrophic response of cardiomyocytes. In a model of phenylephrine-induced hypertrophy, adenovirus-mediated overexpression of DYKR1A completely abrogated the hypertrophic response and significantly reduced the expression of the natriuretic peptides ANF and BNP. Furthermore, DYRK1A blunted cardiomyocyte hypertrophy induced by overexpression of constitutively active calcineurin and attenuated the induction of the hypertrophic gene program. Conversely, knockdown of DYRK1A, utilizing adenoviruses encoding for a specific synthetic miRNA, resulted in an increase in cell surface area accompanied by up-regulation of ANF- mRNA. Similarly, treatment of cardiomyocytes with harmine, a specific inhibitor of DYRK1A, revealed cardiomyocyte hypertrophy on morphological and molecular level. Moreover, constitutively active calcineurin led to robust induction of an NFAT-dependent luciferase reporter, whereas DYRK1A attenuated calcineurin-induced reporter activation in cardiomyocytes. Conversely, both knockdown and pharmacological inhibition of DYRK1A significantly augmented the effect of calcineurin in this assay. In summary, we identified DYRK1A as a novel negative regulator of cardiomyocyte hypertrophy. Mechanistically, this effect appears to be mediated via inhibition of NFAT transcription factors.

DYRK1A Is a Novel Negative Regulator of Cardiomyocyte Hypertrophy*

PubMed Central

Kuhn, Christian; Frank, Derk; Will, Rainer; Jaschinski, Christoph; Frauen, Robert; Katus, Hugo A.; Frey, Norbert

2009-01-01

Activation of the phosphatase calcineurin and its downstream targets, transcription factors of the NFAT family, results in cardiomyocyte hypertrophy. Recently, it has been shown that the dual specificity tyrosine (Y) phosphorylation-regulated kinase 1A (DYRK1A) is able to antagonize calcineurin signaling by directly phosphorylating NFATs. We thus hypothesized that DYRK1A might modulate the hypertrophic response of cardiomyocytes. In a model of phenylephrine-induced hypertrophy, adenovirus-mediated overexpression of DYKR1A completely abrogated the hypertrophic response and significantly reduced the expression of the natriuretic peptides ANF and BNP. Furthermore, DYRK1A blunted cardiomyocyte hypertrophy induced by overexpression of constitutively active calcineurin and attenuated the induction of the hypertrophic gene program. Conversely, knockdown of DYRK1A, utilizing adenoviruses encoding for a specific synthetic miRNA, resulted in an increase in cell surface area accompanied by up-regulation of ANF- mRNA. Similarly, treatment of cardiomyocytes with harmine, a specific inhibitor of DYRK1A, revealed cardiomyocyte hypertrophy on morphological and molecular level. Moreover, constitutively active calcineurin led to robust induction of an NFAT-dependent luciferase reporter, whereas DYRK1A attenuated calcineurin-induced reporter activation in cardiomyocytes. Conversely, both knockdown and pharmacological inhibition of DYRK1A significantly augmented the effect of calcineurin in this assay. In summary, we identified DYRK1A as a novel negative regulator of cardiomyocyte hypertrophy. Mechanistically, this effect appears to be mediated via inhibition of NFAT transcription factors. PMID:19372220

Tunable regulation of CREB DNA binding activity couples genotoxic stress response and metabolism

PubMed Central

Kim, Sang Hwa; Trinh, Anthony T.; Larsen, Michele Campaigne; Mastrocola, Adam S.; Jefcoate, Colin R.; Bushel, Pierre R.; Tibbetts, Randal S.

2016-01-01

cAMP response element binding protein (CREB) is a key regulator of glucose metabolism and synaptic plasticity that is canonically regulated through recruitment of transcriptional coactivators. Here we show that phosphorylation of CREB on a conserved cluster of Ser residues (the ATM/CK cluster) by the DNA damage-activated protein kinase ataxia-telangiectasia-mutated (ATM) and casein kinase1 (CK1) and casein kinase2 (CK2) positively and negatively regulates CREB-mediated transcription in a signal dependent manner. In response to genotoxic stress, phosphorylation of the ATM/CK cluster inhibited CREB-mediated gene expression, DNA binding activity and chromatin occupancy proportional to the number of modified Ser residues. Paradoxically, substoichiometric, ATM-independent, phosphorylation of the ATM/CK cluster potentiated bursts in CREB-mediated transcription by promoting recruitment of the CREB coactivator, cAMP-regulated transcriptional coactivators (CRTC2). Livers from mice expressing a non-phosphorylatable CREB allele failed to attenuate gluconeogenic genes in response to DNA damage or fully activate the same genes in response to glucagon. We propose that phosphorylation-dependent regulation of DNA binding activity evolved as a tunable mechanism to control CREB transcriptional output and promote metabolic homeostasis in response to rapidly changing environmental conditions. PMID:27431323

TRIM25 in the Regulation of the Antiviral Innate Immunity.

PubMed

Martín-Vicente, María; Medrano, Luz M; Resino, Salvador; García-Sastre, Adolfo; Martínez, Isidoro

2017-01-01

TRIM25 is an E3 ubiquitin ligase enzyme that is involved in various cellular processes, including regulation of the innate immune response against viruses. TRIM25-mediated ubiquitination of the cytosolic pattern recognition receptor RIG-I is an essential step for initiation of the intracellular antiviral response and has been thoroughly documented. In recent years, however, additional roles of TRIM25 in early innate immunity are emerging, including negative regulation of RIG-I, activation of the melanoma differentiation-associated protein 5-mitochondrial antiviral signaling protein-TRAF6 antiviral axis and modulation of p53 levels and activity. In addition, the ability of TRIM25 to bind RNA may uncover new mechanisms by which this molecule regulates intracellular signaling and/or RNA virus replication.

Mindfulness in schizophrenia: Associations with self-reported motivation, emotion regulation, dysfunctional attitudes, and negative symptoms.

PubMed

Tabak, Naomi T; Horan, William P; Green, Michael F

2015-10-01

Mindfulness-based interventions are gaining empirical support as alternative or adjunctive treatments for a variety of mental health conditions, including anxiety, depression, and substance use disorders. Emerging evidence now suggests that mindfulness-based treatments may also improve clinical features of schizophrenia, including negative symptoms. However, no research has examined the construct of mindfulness and its correlates in schizophrenia. In this study, we examined self-reported mindfulness in patients (n=35) and controls (n=25) using the Five-Facet Mindfulness Questionnaire. We examined correlations among mindfulness, negative symptoms, and psychological constructs associated with negative symptoms and adaptive functioning, including motivation, emotion regulation, and dysfunctional attitudes. As hypothesized, patients endorsed lower levels of mindfulness than controls. In patients, mindfulness was unrelated to negative symptoms, but it was associated with more adaptive emotion regulation (greater reappraisal) and beliefs (lower dysfunctional attitudes). Some facets of mindfulness were also associated with self-reported motivation (behavioral activation and inhibition). These patterns of correlations were similar in patients and controls. Findings from this initial study suggest that schizophrenia patients may benefit from mindfulness-based interventions because they (a) have lower self-reported mindfulness than controls and (b) demonstrate strong relationships between mindfulness and psychological constructs related to adaptive functioning. Copyright © 2015 Elsevier B.V. All rights reserved.

TNF-alpha increases ubiquitin-conjugating activity in skeletal muscle by up-regulating UbcH2/E220k

NASA Technical Reports Server (NTRS)

Li, Yi-Ping; Lecker, Stewart H.; Chen, Yuling; Waddell, Ian D.; Goldberg, Alfred L.; Reid, Michael B.

2003-01-01

In some inflammatory diseases, TNF-alpha is thought to stimulate muscle catabolism via an NF-kappaB-dependent process that increases ubiquitin conjugation to muscle proteins. The transcriptional mechanism of this response has not been determined. Here we studied the potential role of UbcH2, a ubiquitin carrier protein and homologue of murine E220k. We find that UbcH2 is constitutively expressed by human skeletal and cardiac muscles, murine limb muscle, and cultured myotubes. TNF-alpha stimulates UbcH2 expression in mouse limb muscles in vivo and in cultured myotubes. The UbcH2 promoter region contains a functional NF-kappaB binding site; NF-kappaB binding to this sequence is increased by TNF-alpha stimulation. A dominant negative inhibitor of NF-kappaB activation blocks both UbcH2 up-regulation and the increase in ubiquitin-conjugating activity stimulated by TNF-alpha. In extracts from TNF-alpha-treated myotubes, ubiquitin-conjugating activity is limited by UbcH2 availability; activity is inhibited by an antiserum to UbcH2 or a dominant negative mutant of UbcH2 and is enhanced by wild-type UbcH2. Thus, UbcH2 up-regulation is a novel response to TNF-alpha/NF-kappaB signaling in skeletal muscle that appears to be essential for the increased ubiquitin conjugation induced by this cytokine.

Dopamine negatively modulates the NCA ion channels in C. elegans

PubMed Central

Topalidou, Irini; Pereira, Laura

2017-01-01

The NALCN/NCA ion channel is a cation channel related to voltage-gated sodium and calcium channels. NALCN has been reported to be a sodium leak channel with a conserved role in establishing neuronal resting membrane potential, but its precise cellular role and regulation are unclear. The Caenorhabditis elegans orthologs of NALCN, NCA-1 and NCA-2, act in premotor interneurons to regulate motor circuit activity that sustains locomotion. Recently we found that NCA-1 and NCA-2 are activated by a signal transduction pathway acting downstream of the heterotrimeric G protein Gq and the small GTPase Rho. Through a forward genetic screen, here we identify the GPCR kinase GRK-2 as a new player affecting signaling through the Gq-Rho-NCA pathway. Using structure-function analysis, we find that the GPCR phosphorylation and membrane association domains of GRK-2 are required for its function. Genetic epistasis experiments suggest that GRK-2 acts on the D2-like dopamine receptor DOP-3 to inhibit Go signaling and positively modulate NCA-1 and NCA-2 activity. Through cell-specific rescuing experiments, we find that GRK-2 and DOP-3 act in premotor interneurons to modulate NCA channel function. Finally, we demonstrate that dopamine, through DOP-3, negatively regulates NCA activity. Thus, this study identifies a pathway by which dopamine modulates the activity of the NCA channels. PMID:28968387

Dopamine negatively modulates the NCA ion channels in C. elegans.

PubMed

Topalidou, Irini; Cooper, Kirsten; Pereira, Laura; Ailion, Michael

2017-10-01

The NALCN/NCA ion channel is a cation channel related to voltage-gated sodium and calcium channels. NALCN has been reported to be a sodium leak channel with a conserved role in establishing neuronal resting membrane potential, but its precise cellular role and regulation are unclear. The Caenorhabditis elegans orthologs of NALCN, NCA-1 and NCA-2, act in premotor interneurons to regulate motor circuit activity that sustains locomotion. Recently we found that NCA-1 and NCA-2 are activated by a signal transduction pathway acting downstream of the heterotrimeric G protein Gq and the small GTPase Rho. Through a forward genetic screen, here we identify the GPCR kinase GRK-2 as a new player affecting signaling through the Gq-Rho-NCA pathway. Using structure-function analysis, we find that the GPCR phosphorylation and membrane association domains of GRK-2 are required for its function. Genetic epistasis experiments suggest that GRK-2 acts on the D2-like dopamine receptor DOP-3 to inhibit Go signaling and positively modulate NCA-1 and NCA-2 activity. Through cell-specific rescuing experiments, we find that GRK-2 and DOP-3 act in premotor interneurons to modulate NCA channel function. Finally, we demonstrate that dopamine, through DOP-3, negatively regulates NCA activity. Thus, this study identifies a pathway by which dopamine modulates the activity of the NCA channels.

HAT1 induces lung cancer cell apoptosis via up regulating Fas.

PubMed

Han, Na; Shi, Lei; Guo, Qiuyun; Sun, Wei; Yu, Yang; Yang, Li; Zhang, Xiaoxi; Zhang, Mengxian

2017-10-27

The dysfunction of apoptosis is one of the factors contributing to lung cancer (LC) growth. Histone acetyltransferase HAT1 can up regulate cell apoptosis. This study aims to investigate the mechanism by which HAT1 induces LC cell (LCC) apoptosis via up regulating the expression of Fas. In this study, the surgically removed human LC tissues were collected. LCCs were isolated from the LC tissues and analyzed for the expression of HAT1 and Fas by RT-qPCR and Western blotting. We observed that the expression of Fas was negatively correlated with PAR2 in LCCs. Activation of PAR2 suppressed the expression of Fas in normal lung epithelial cells. The expression of HAT1 was lower and positively correlated with Fas expression and negatively correlated with PAR2 expression in LCCs. Activation of PAR2 suppressed Fas expression in lung epithelial cells via inhibiting HAT1. Restoration of HAT1 expression restored Fas expression in LCCs and induced LCC apoptosis. In conclusion, less expression of HAT1 in LCCs was associated with the pathogenesis of LC. Up regulation of HAT1 expression in LCCs can induce LCCs apoptosis, which may be a potential novel therapy for the treatment of LC.

Neural correlates of the affect regulation model in schizophrenia patients with substance use history: a functional magnetic resonance imaging study.

PubMed

Mancini-Marïe, Adham; Potvin, Stéphane; Fahim, Cherine; Beauregard, Mario; Mensour, Boualem; Stip, Emmanuel

2006-03-01

The lifetime prevalence of substance use disorders among schizophrenia patients is close to 50%. The negative consequences of substance abuse in schizophrenia are well documented, but the etiology of this comorbid condition remains unknown. According to the affect regulation model, schizophrenia patients abuse drugs in order to cope with their negative affects. Supporting the model, clinical studies have shown that dual-diagnosis patients have less blunting of affect and that they experience more negative affect. We hypothesized that patients with a history of substance use would have increased cerebral activations in response to aversive stimuli when compared to abstinent patients. Schizophrenia patients were divided into 2 groups: patients with (SCZ-SU group; N = 12) and without (SCZ group; N = 11) a current or past substance use disorder (alcohol, cannabis, and/or LSD). Diagnoses were made according to DSM-IV criteria. Using functional magnetic resonance imaging (fMRI), patients were scanned during passive viewing of emotionally negative pictures (International Affective Picture System). Data were gathered from September 2001 to December 2003. Subjectively, the emotional experience induced by viewing the negative pictures was rated significantly higher in the SCZ-SU group than in the SCZ group (p = .008). Neurally, in the SCZ-SU group, significant loci of activation were identified in the right medial prefrontal cortex (Brodmann's area [BA] 10), left medial prefrontal cortex (BA 10), right orbitofrontal cortex (BA 47), and left amygdala. No significant loci of activation were observed in the SCZ group. These results suggest that the functioning of the medial prefrontal cortex, thought to be impaired in patients with prominent negative symptoms, is more preserved in dual-diagnosis schizophrenia. This relative preservation could be primary or secondary to substance use.

Abnormal brain activation during directed forgetting of negative memory in depressed patients.

PubMed

Yang, Wenjing; Chen, Qunlin; Liu, Peiduo; Cheng, Hongsheng; Cui, Qian; Wei, Dongtao; Zhang, Qinglin; Qiu, Jiang

2016-01-15

The frequent occurrence of uncontrollable negative thoughts and memories is a troubling aspect of depression. Thus, knowledge on the mechanism underlying intentional forgetting of these thoughts and memories is crucial to develop an effective emotion regulation strategy for depressed individuals. Behavioral studies have demonstrated that depressed participants cannot intentionally forget negative memories. However, the neural mechanism underlying this process remains unclear. In this study, participants completed the directed forgetting task in which they were instructed to remember or forget neutral or negative words. Standard univariate analysis based on the General Linear Model showed that the depressed participants have higher activation in the inferior frontal gyrus (IFG), superior frontal gyrus (SFG), superior parietal gyrus (SPG), and inferior temporal gyrus (ITG) than the healthy individuals. The results indicated that depressed participants recruited more frontal and parietal inhibitory control resources to inhibit the TBF items, but the attempt still failed because of negative bias. We also used the Support Vector Machine to perform multivariate pattern classification based on the brain activation during directed forgetting. The pattern of brain activity in directed forgetting of negative words allowed correct group classification with an overall accuracy of 75% (P=0.012). The brain regions which are critical for this discrimination showed abnormal activation when depressed participants were attempting to forget negative words. These results indicated that the abnormal neural circuitry when depressed individuals tried to forget the negative words might provide neurobiological markers for depression. Copyright © 2015 Elsevier B.V. All rights reserved.

PecS regulates the urate-responsive expression of type 1 fimbriae in Klebsiella pneumoniae CG43.

PubMed

Wang, Zhe-Chong; Liu, Chia-Jui; Huang, Ying-Jung; Wang, Yu-Seng; Peng, Hwei-Ling

2015-12-01

In the Klebsiella pneumoniae CG43 genome, the divergently transcribed genes coding for PecS, the MarR-type transcription factor, and PecM, the drug metabolite transporter, are located between the type 1 and type 3 fimbrial gene clusters. The intergenic sequence pecO between pecS and pecM contains three putative PecS binding sites and a CpxR box. Electrophoretic mobility shift assay revealed that the recombinant PecS and CpxR could specifically bind to the pecO sequence, and the specific interaction of PecS and pecO could be attenuated by urate. The expression of pecS and pecM was negatively regulated by CpxAR and PecS, and was inducible by exogenous urate in the absence of cpxAR. Compared with CG43S3ΔcpxAR, the derived mutants CG43S3ΔcpxARΔpecS and CG43S3ΔcpxARΔpecSΔpecM exerted similar levels of sensitivity to H2O2 or paraquat, but higher levels of mannose-sensitive yeast agglutination activity and FimA production. The promoter activity and transcript levels of fimA in CG43S3ΔcpxAR were also increased by deleting pecS. However, no binding activity between PecS and the fimA promoter could be observed. Nevertheless, PecS deletion could reduce the expression of the global regulator HNS and release the negative effect of HNS on FimA expression. In CG43S3ΔcpxAR, the expression of FimA as well as PecS was inducible by urate, whilst urate-induced FimA expression was inhibited by the deletion of pecS. Taken together, we propose that K. pneumoniae PecS indirectly and negatively regulates the expression of type 1 fimbriae, and the regulation is urate-inducible in the absence of CpxAR.

Corticotrigeminal Projections from the Insular Cortex to the Trigeminal Caudal Subnucleus Regulate Orofacial Pain after Nerve Injury via Extracellular Signal-Regulated Kinase Activation in Insular Cortex Neurons.

PubMed

Wang, Jian; Li, Zhi-Hua; Feng, Ban; Zhang, Ting; Zhang, Han; Li, Hui; Chen, Tao; Cui, Jing; Zang, Wei-Dong; Li, Yun-Qing

2015-01-01

Cortical neuroplasticity alterations are implicated in the pathophysiology of chronic orofacial pain. However, the relationship between critical cortex excitability and orofacial pain maintenance has not been fully elucidated. We recently demonstrated a top-down corticospinal descending pain modulation pathway from the anterior cingulate cortex (ACC) to the spinal dorsal horn that could directly regulate nociceptive transmission. Thus, we aimed to investigate possible corticotrigeminal connections that directly influence orofacial nociception in rats. Infraorbital nerve chronic constriction injury (IoN-CCI) induced significant orofacial nociceptive behaviors as well as pain-related negative emotions such as anxiety/depression in rats. By combining retrograde and anterograde tract tracing, we found powerful evidence that the trigeminal caudal subnucleus (Vc), especially the superficial laminae (I/II), received direct descending projections from granular and dysgranular parts of the insular cortex (IC). Extracellular signal-regulated kinase (ERK), an important signaling molecule involved in neuroplasticity, was significantly activated in the IC following IoN-CCI. Moreover, in IC slices from IoN-CCI rats, U0126, an inhibitor of ERK activation, decreased both the amplitude and the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) and reduced the paired-pulse ratio (PPR) of Vc-projecting neurons. Additionally, U0126 also reduced the number of action potentials in the Vc-projecting neurons. Finally, intra-IC infusion of U0126 obviously decreased Fos expression in the Vc, accompanied by the alleviation of both nociceptive behavior and negative emotions. Thus, the corticotrigeminal descending pathway from the IC to the Vc could directly regulate orofacial pain, and ERK deactivation in the IC could effectively alleviate neuropathic pain as well as pain-related negative emotions in IoN-CCI rats, probably through this top-down pathway. These findings may help researchers and clinicians to better understand the underlying modulation mechanisms of orofacial neuropathic pain and indicate a novel mechanism of ERK inhibitor-induced analgesia.

MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

PubMed

Xu, Hui; Yan, Yaping; Williams, Mark S; Carey, Gregory B; Yang, Jingxian; Li, Hongmei; Zhang, Guang-Xian; Rostami, Abdolmohamad

2010-11-01

MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK) and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

DELLA proteins negatively regulate dark-induced senescence and chlorophyll degradation in Arabidopsis through interaction with the transcription factor WRKY6.

PubMed

Zhang, Yongqiang; Liu, Zhongjuan; Wang, Xiaoyun; Wang, Jianfeng; Fan, Kai; Li, Zhaowei; Lin, Wenxiong

2018-03-24

DELLA proteins' negative regulation of dark-induced senescence and chlorophyll degradation in Arabidopsis is through interaction with WRKY6 and thus repression of its transcriptional activities on senescence-related genes. Senescence is an intricate and highly orchestrated process regulated by numerous endogenous and environmental signals. Gibberellins (GAs) and their signaling components DELLA proteins have been known to participate in the regulation of senescence. However, the mechanism of the GA-DELLA system involved in the senescence process remains largely unclear. Darkness is a known environmental factor that induces plant senescence. In this study, exogenous GA 3 (an active form of GA) accelerated but paclobutrazol (a specific GA biosynthesis inhibitor) retarded dark-induced leaf yellowing in Arabidopsis. Moreover, the dark-triggered decrease in chlorophyll content, increase in cell membrane leakage, and upregulation of senescence-associated genes were notably impaired in both endogenous GA-decreased mutants ga3ox1/ga3ox2 and ga20ox1/ga20ox2 compared with those in wild-type Col-0. These effects of darkness were enhanced in the quintuple mutant of DELLA genes gai-t6/rga-t2/rgl1-1/rgl2-1/rgl3-1 and conversely attenuated in the gain-of-function mutant gai and transgenic plant 35S::TAP-RGAd17 compared with wild-type Ler. Subsequently, RGA interacted with the transcription factor WRKY6 in a yeast two-hybrid assay, as confirmed by bimolecular fluorescence complementation and pull-down analyses. In addition, mutation and overexpression of WRKY6 retarded and accelerated dark-induced senescence, respectively. Furthermore, transient expression assays in Arabidopsis protoplasts indicated that RGA and GAI weakened the transcriptional activities of WRKY6 on its downstream senescence-related genes, including SAG13 and SGR. Taken together, these results suggest that GAs positively and DELLAs negatively regulate dark-induced senescence and chlorophyll degradation in Arabidopsis. DELLAs function in this process, at least in part, by interacting with WRKY6.

Gender and neural substrates subserving implicit processing of death-related linguistic cues.

PubMed

Qin, Jungang; Shi, Zhenhao; Ma, Yina; Han, Shihui

2018-02-01

Our recent functional magnetic resonance imaging study revealed decreased activities in the anterior cingulate cortex (ACC) and bilateral insula for women during the implicit processing of death-related linguistic cues. Current work tested whether aforementioned activities are common for women and men and explored potential gender differences. We scanned twenty males while they performed a color-naming task on death-related, negative-valence, and neutral-valence words. Whole-brain analysis showed increased left frontal activity and decreased activities in the ACC and bilateral insula to death-related versus negative-valence words for both men and women. However, relative to women, men showed greater increased activity in the left middle frontal cortex and decreased activity in the right cerebellum to death-related versus negative-valence words. The results suggest, while implicit processing of death-related words is characterized with weakened sense of oneself for both women and men, men may recruit stronger cognitive regulation of emotion than women.

Cot/Tpl2 regulates IL-23 p19 expression in LPS-stimulated macrophages through ERK activation.

PubMed

Kakimoto, K; Musikacharoen, T; Chiba, N; Bandow, K; Ohnishi, T; Matsuguchi, T

2010-03-01

We have previously reported that a serine/threonine protein kinase, Cot/Tpl2, is a negative regulator of Th1-type immunity through inhibiting IL-12 expression in antigen presenting cells (APCs) stimulated by Toll-like receptor (TLR) ligands. We here show that Cot/Tpl2(-/-) macrophages produce significantly less IL-23, an important regulator of Th17-type response, than the wild-type counterparts in response to lipopolysaccharide (LPS), which is a ligand for TLR4. The decreased IL-23 production in Cot/Tpl2(-/-) macrophages is, at least partly, regulated at the transcriptional level, as the LPS-mediated IL-23 p19 mRNA induction was significantly less in Cot/Tpl2(-/-) macrophages. Chemical inhibition of extracellular signal-regulated kinase (ERK) activity similarly inhibited IL-23 expression in LPS-stimulated wild-type macrophages. As Cot/Tpl2 is an essential upstream component of the ERK activation pathway of LPS, it is suggested that Cot/Tpl2 positively regulates IL-23 expression through ERK activation. These results indicate that Cot/Tpl2 may be involved in balancing Th1/Th17 differentiation by regulating the expression ratio of IL-12 and IL-23 in APCs.

ACTIVITY-DEPENDENT, STRESS-RESPONSIVE BDNF SIGNALING AND THE QUEST FOR OPTIMAL BRAIN HEALTH AND RESILIENCE THROUGHOUT THE LIFESPAN

PubMed Central

Rothman, S. M.; Mattson, M. P.

2013-01-01

During development of the nervous system, the formation of connections (synapses) between neurons is dependent upon electrical activity in those neurons, and neurotrophic factors produced by target cells play a pivotal role in such activity-dependent sculpting of the neural networks. A similar interplay between neurotransmitter and neurotrophic factor signaling pathways mediates adaptive responses of neural networks to environmental demands in adult mammals, with the excitatory neurotransmitter glutamate and brain-derived neurotrophic factor (BDNF) being particularly prominent regulators of synaptic plasticity throughout the central nervous system. Optimal brain health throughout the lifespan is promoted by intermittent challenges such as exercise, cognitive stimulation and dietary energy restriction, that subject neurons to activity-related metabolic stress. At the molecular level, such challenges to neurons result in the production of proteins involved in neurogenesis, learning and memory and neuronal survival; examples include proteins that regulate mitochondrial biogenesis, protein quality control, and resistance of cells to oxidative, metabolic and proteotoxic stress. BDNF signaling mediates up-regulation of several such proteins including the protein chaperone GRP-78, antioxidant enzymes, the cell survival protein Bcl-2, and the DNA repair enzyme APE1. Insufficient exposure to such challenges, genetic factors may conspire to impair BDNF production and/or signaling resulting in the vulnerability of the brain to injury and neurodegenerative disorders including Alzheimer’s, Parkinson’s and Huntington’s diseases. Further, BDNF signaling is negatively regulated by glucocorticoids. Glucocorticoids impair synaptic plasticity in the brain by negatively regulating spine density, neurogenesis and long-term potentiation, effects that are potentially linked to glucocorticoid regulation of BDNF. Findings suggest that BDNF signaling in specific brain regions mediates some of the beneficial effects of exercise and energy restriction on peripheral energy metabolism and the cardiovascular system. Collectively, the findings described in this article suggest the possibility of developing prescriptions for optimal brain health based on activity-dependent BDNF signaling. PMID:23079624

Regulation of Neurite Outgrowth in N1E-115 Cells through PDZ-Mediated Recruitment of Diacylglycerol Kinase ζ

PubMed Central

Yakubchyk, Yury; Abramovici, Hanan; Maillet, Jean-Christian; Daher, Elias; Obagi, Christopher; Parks, Robin J.; Topham, Matthew K.; Gee, Stephen H.

2005-01-01

Syntrophins are scaffold proteins that regulate the subcellular localization of diacylglycerol kinase ζ (DGK-ζ), an enzyme that phosphorylates the lipid second-messenger diacylglycerol to yield phosphatidic acid. DGK-ζ and syntrophins are abundantly expressed in neurons of the developing and adult brain, but their function is unclear. Here, we show that they are present in cell bodies, neurites, and growth cones of cultured cortical neurons and differentiated N1E-115 neuroblastoma cells. Overexpression of DGK-ζ in N1E-115 cells induced neurite formation in the presence of serum, which normally prevents neurite outgrowth. This effect was independent of DGK-ζ kinase activity but dependent on a functional C-terminal PDZ-binding motif, which specifically interacts with syntrophin PDZ domains. DGK-ζ mutants with a blocked C terminus acted as dominant-negative inhibitors of outgrowth from serum-deprived N1E-115 cells and cortical neurons. Several lines of evidence suggest DGK-ζ promotes neurite outgrowth through association with the GTPase Rac1. DGK-ζ colocalized with Rac1 in neuronal processes and DGK-ζ-induced outgrowth was inhibited by dominant-negative Rac1. Moreover, DGK-ζ directly interacts with Rac1 through a binding site located within its C1 domains. Together with syntrophin, these proteins form a tertiary complex in N1E-115 cells. A DGK-ζ mutant that mimics phosphorylation of the MARCKS domain was unable to bind an activated Rac1 mutant (Rac1V12) and phorbol myristate acetate-induced protein kinase C activation inhibited the interaction of DGK-ζ with Rac1V12, suggesting protein kinase C-mediated phosphorylation of the MARCKS domain negatively regulates DGK-ζ binding to active Rac1. Collectively, these findings suggest DGK-ζ, syntrophin, and Rac1 form a regulated signaling complex that controls polarized outgrowth in neuronal cells. PMID:16055737

NLRP3 inflammasome inhibition is disrupted in a group of auto-inflammatory disease CAPS mutations.

PubMed

Mortimer, Leanne; Moreau, France; MacDonald, Justin A; Chadee, Kris

2016-10-01

Inflammasomes are positioned to rapidly escalate the intensity of inflammation by activating interleukin (IL)-1β, IL-18 and cell death by pyroptosis. However, negative regulation of inflammasomes remains poorly understood, as is the signaling cascade that dampens inflammasome activity. We found that rapid NLRP3 inflammasome activation was directly inhibited by protein kinase A (PKA), which was induced by prostaglandin E2 (PGE2) signaling via the PGE2 receptor E-prostanoid 4 (EP4). PKA directly phosphorylated the cytoplasmic receptor NLRP3 and attenuated its ATPase function. We found that Ser295 in human NLRP3 was critical for rapid inhibition and PKA phosphorylation. Mutations in NLRP3-encoding residues adjacent to Ser295 have been linked to the inflammatory disease CAPS (cryopyrin-associated periodic syndromes). NLRP3-S295A phenocopied the human CAPS mutants. These data suggest that negative regulation at Ser295 is critical for restraining the NLRP3 inflammasome and identify a molecular basis for CAPS-associated NLRP3 mutations.

TACE (ADAM17) inhibits Schwann cell myelination

PubMed Central

Marca, Rosa La; Cerri, Federica; Horiuchi, Keisuke; Bachi, Angela; Feltri, M Laura; Wrabetz, Lawrence; Blobel, Carl P; Quattrini, Angelo; Salzer, James L; Taveggia, Carla

2012-01-01

Tumor necrosis factor-α–converting enzyme (TACE; also known as ADAM17) is a proteolytic sheddase that is responsible for the cleavage of several membrane-bound molecules. We report that TACE cleaves neuregulin-1 (NRG1) type III in the epidermal growth factor domain, probably inactivating it (as assessed by deficient activation of the phosphatidylinositol-3-OH kinase pathway), and thereby negatively regulating peripheral nervous system (PNS) myelination. Lentivirus-mediated knockdown of TACE in vitro in dorsal root ganglia neurons accelerates the onset of myelination and results in hypermyelination. In agreement, motor neurons of conditional knockout mice lacking TACE specifically in these cells are significantly hypermyelinated, and small-caliber fibers are aberrantly myelinated. Further, reduced TACE activity rescues hypomyelination in NRG1 type III haploinsufficient mice in vivo. We also show that the inhibitory effect of TACE is neuron-autonomous, as Schwann cells lacking TACE elaborate myelin of normal thickness. Thus, TACE is a modulator of NRG1 type III activity and is a negative regulator of myelination in the PNS. PMID:21666671

Negative regulation of glial engulfment activity by Draper terminates glial responses to axon injury

PubMed Central

Logan, Mary A.; Hackett, Rachel; Doherty, Johnna; Sheehan, Amy; Speese, Sean D.; Freeman, Marc R.

2012-01-01

Neuronal injury elicits potent cellular responses from glia, but molecular pathways modulating glial activation, phagocytic function, and termination of reactive responses remain poorly defined. Here we show that positive or negative regulation of glial reponses to axon injury are molecularly encoded by unique isoforms of the Drosophila engulfment receptor Draper. Draper-I promotes engulfment of axonal debris through an immunoreceptor tyrosine-based activation motif (ITAM). In contrast, Draper-II, an alternative splice variant, potently inhibits glial engulfment function. Draper-II suppresses Draper-I signaling through a novel immunoreceptor tyrosine-based inhibitory motif (ITIM)-like domain and the tyrosine phosphatase Corkscrew (Csw). Intriguingly, loss of Draper-II/Csw signaling prolongs expression of glial engulfment genes after axotomy and reduces the ability of glia to respond to secondary axotomy. Our work highlights a novel role for Draper-II in inhibiting glial responses to neurodegeneration, and indicates a balance of opposing Draper-I/-II signaling events is essential to maintain glial sensitivity to brain injury. PMID:22426252

NF-κB in Hematological Malignancies

PubMed Central

Imbert, Véronique; Peyron, Jean-François

2017-01-01

NF-κB (Nuclear Factor Κ-light-chain-enhancer of activated B cells) transcription factors are critical regulators of immunity, stress response, apoptosis, and differentiation. Molecular defects promoting the constitutive activation of canonical and non-canonical NF-κB signaling pathways contribute to many diseases, including cancer, diabetes, chronic inflammation, and autoimmunity. In the present review, we focus our attention on the mechanisms of NF-κB deregulation in hematological malignancies. Key positive regulators of NF-κB signaling can act as oncogenes that are often prone to chromosomal translocation, amplifications, or activating mutations. Negative regulators of NF-κB have tumor suppressor functions, and are frequently inactivated either by genomic deletions or point mutations. NF-κB activation in tumoral cells is also driven by the microenvironment or chronic signaling that does not rely on genetic alterations. PMID:28561798

Adipocyte iron regulates leptin and food intake

PubMed Central

Gao, Yan; Li, Zhonggang; Gabrielsen, J. Scott; Simcox, Judith A.; Lee, Soh-hyun; Jones, Deborah; Cooksey, Bob; Stoddard, Gregory; Cefalu, William T.; McClain, Donald A.

2015-01-01

Dietary iron supplementation is associated with increased appetite. Here, we investigated the effect of iron on the hormone leptin, which regulates food intake and energy homeostasis. Serum ferritin was negatively associated with serum leptin in a cohort of patients with metabolic syndrome. Moreover, the same inverse correlation was observed in mice fed a high-iron diet. Adipocyte-specific loss of the iron exporter ferroportin resulted in iron loading and decreased leptin, while decreased levels of hepcidin in a murine hereditary hemochromatosis (HH) model increased adipocyte ferroportin expression, decreased adipocyte iron, and increased leptin. Treatment of 3T3-L1 adipocytes with iron decreased leptin mRNA in a dose-dependent manner. We found that iron negatively regulates leptin transcription via cAMP-responsive element binding protein activation (CREB activation) and identified 2 potential CREB-binding sites in the mouse leptin promoter region. Mutation of both sites completely blocked the effect of iron on promoter activity. ChIP analysis revealed that binding of phosphorylated CREB is enriched at these two sites in iron-treated 3T3-L1 adipocytes compared with untreated cells. Consistent with the changes in leptin, dietary iron content was also directly related to food intake, independently of weight. These findings indicate that levels of dietary iron play an important role in regulation of appetite and metabolism through CREB-dependent modulation of leptin expression. PMID:26301810

Recovery from Unrecognized Sleep Loss Accumulated in Daily Life Improved Mood Regulation via Prefrontal Suppression of Amygdala Activity

PubMed Central

Motomura, Yuki; Kitamura, Shingo; Nakazaki, Kyoko; Oba, Kentaro; Katsunuma, Ruri; Terasawa, Yuri; Hida, Akiko; Moriguchi, Yoshiya; Mishima, Kazuo

2017-01-01

Many modern people suffer from sleep debt that has accumulated in everyday life but is not subjectively noticed [potential sleep debt (PSD)]. Our hypothesis for this study was that resolution of PSD through sleep extension optimizes mood regulation by altering the functional connectivity between the amygdala and prefrontal cortex. Fifteen healthy male participants underwent an experiment consisting of a baseline (BL) evaluation followed by two successive interventions, namely, a 9-day sleep extension followed by one night of total sleep deprivation (TSD). Tests performed before and after the interventions included a questionnaire on negative mood and neuroimaging with arterial spin labeling MRI for evaluating regional cerebral blood flow (rCBF) and functional connectivity. Negative mood and amygdala rCBF were significantly reduced after sleep extension compared with BL. The amygdala had a significant negative functional connectivity with the medial prefrontal cortex (FCamg–MPFC), and this negative connectivity was greater after sleep extension than at BL. After TSD, these indices reverted to the same level as at BL. An additional path analysis with structural equation modeling showed that the FCamg–MPFC significantly explained the amygdala rCBF and that the amygdala rCBF significantly explained the negative mood. These findings suggest that the use of our sleep extension protocol normalized amygdala activity via negative amygdala–MPFC functional connectivity. The resolution of unnoticed PSD may improve mood by enhancing frontal suppression of hyperactivity in the amygdala caused by PSD accumulating in everyday life. PMID:28713328

Mitochondrial flashes regulate ATP homeostasis in the heart

PubMed Central

Wang, Xianhua; Zhang, Xing; Wu, Di; Huang, Zhanglong; Hou, Tingting; Jian, Chongshu; Yu, Peng; Lu, Fujian; Zhang, Rufeng; Sun, Tao; Li, Jinghang; Qi, Wenfeng; Wang, Yanru; Gao, Feng; Cheng, Heping

2017-01-01

The maintenance of a constant ATP level (‘set-point’) is a vital homeostatic function shared by eukaryotic cells. In particular, mammalian myocardium exquisitely safeguards its ATP set-point despite 10-fold fluctuations in cardiac workload. However, the exact mechanisms underlying this regulation of ATP homeostasis remain elusive. Here we show mitochondrial flashes (mitoflashes), recently discovered dynamic activity of mitochondria, play an essential role for the auto-regulation of ATP set-point in the heart. Specifically, mitoflashes negatively regulate ATP production in isolated respiring mitochondria and, their activity waxes and wanes to counteract the ATP supply-demand imbalance caused by superfluous substrate and altered workload in cardiomyocytes. Moreover, manipulating mitoflash activity is sufficient to inversely shift the otherwise stable ATP set-point. Mechanistically, the Bcl-xL-regulated proton leakage through F1Fo-ATP synthase appears to mediate the coupling between mitoflash production and ATP set-point regulation. These findings indicate mitoflashes appear to constitute a digital auto-regulator for ATP homeostasis in the heart. DOI: http://dx.doi.org/10.7554/eLife.23908.001 PMID:28692422

A peptide export-import control circuit modulating bacterial development regulates protein phosphatases of the phosphorelay.

PubMed

Perego, M

1997-08-05

The phosphorelay signal transduction system activates developmental transcription in sporulation of Bacillus subtilis by phosphorylation of aspartyl residues of the Spo0F and Spo0A response regulators. The phosphorylation level of these response regulators is determined by the opposing activities of protein kinases and protein aspartate phosphatases that interpret positive and negative signals for development in a signal integration circuit. The RapA protein aspartate phosphatase of the phosphorelay is regulated by a peptide that directly inhibits its activity. This peptide is proteolytically processed from an inactive pre-inhibitor protein encoded in the phrA gene. The pre-inhibitor is cleaved by the protein export apparatus to a putative pro-inhibitor that is further processed to the active inhibitor peptide and internalized by the oligopeptide permease. This export-import circuit is postulated to be a mechanism for timing phosphatase activity where the processing enzymes regulate the rate of formation of the active inhibitor. The processing events may, in turn, be controlled by a regulatory hierarchy. Chromosome sequencing has revealed several other phosphatase-prepeptide gene pairs in B. subtilis, suggesting that the use of this mechanism may be widespread in signal transduction.

A peptide export–import control circuit modulating bacterial development regulates protein phosphatases of the phosphorelay

PubMed Central

Perego, Marta

1997-01-01

The phosphorelay signal transduction system activates developmental transcription in sporulation of Bacillus subtilis by phosphorylation of aspartyl residues of the Spo0F and Spo0A response regulators. The phosphorylation level of these response regulators is determined by the opposing activities of protein kinases and protein aspartate phosphatases that interpret positive and negative signals for development in a signal integration circuit. The RapA protein aspartate phosphatase of the phosphorelay is regulated by a peptide that directly inhibits its activity. This peptide is proteolytically processed from an inactive pre-inhibitor protein encoded in the phrA gene. The pre-inhibitor is cleaved by the protein export apparatus to a putative pro-inhibitor that is further processed to the active inhibitor peptide and internalized by the oligopeptide permease. This export–import circuit is postulated to be a mechanism for timing phosphatase activity where the processing enzymes regulate the rate of formation of the active inhibitor. The processing events may, in turn, be controlled by a regulatory hierarchy. Chromosome sequencing has revealed several other phosphatase–prepeptide gene pairs in B. subtilis, suggesting that the use of this mechanism may be widespread in signal transduction. PMID:9238025

Transcription of two adjacent carbohydrate utilization gene clusters in Bifidobacterium breve UCC2003 is controlled by LacI- and repressor open reading frame kinase (ROK)-type regulators.

PubMed

O'Connell, Kerry Joan; Motherway, Mary O'Connell; Liedtke, Andrea; Fitzgerald, Gerald F; Paul Ross, R; Stanton, Catherine; Zomer, Aldert; van Sinderen, Douwe

2014-06-01

Members of the genus Bifidobacterium are commonly found in the gastrointestinal tracts of mammals, including humans, where their growth is presumed to be dependent on various diet- and/or host-derived carbohydrates. To understand transcriptional control of bifidobacterial carbohydrate metabolism, we investigated two genetic carbohydrate utilization clusters dedicated to the metabolism of raffinose-type sugars and melezitose. Transcriptomic and gene inactivation approaches revealed that the raffinose utilization system is positively regulated by an activator protein, designated RafR. The gene cluster associated with melezitose metabolism was shown to be subject to direct negative control by a LacI-type transcriptional regulator, designated MelR1, in addition to apparent indirect negative control by means of a second LacI-type regulator, MelR2. In silico analysis, DNA-protein interaction, and primer extension studies revealed the MelR1 and MelR2 operator sequences, each of which is positioned just upstream of or overlapping the correspondingly regulated promoter sequences. Similar analyses identified the RafR binding operator sequence located upstream of the rafB promoter. This study indicates that transcriptional control of gene clusters involved in carbohydrate metabolism in bifidobacteria is subject to conserved regulatory systems, representing either positive or negative control.

POSH regulates Hippo signaling through ubiquitin-mediated expanded degradation.

PubMed

Ma, Xianjue; Guo, Xiaowei; Richardson, Helena E; Xu, Tian; Xue, Lei

2018-02-27

The Hippo signaling pathway is a master regulator of organ growth, tissue homeostasis, and tumorigenesis. The activity of the Hippo pathway is controlled by various upstream components, including Expanded (Ex), but the precise molecular mechanism of how Ex is regulated remains poorly understood. Here we identify Plenty of SH3s (POSH), an E3 ubiquitin ligase, as a key component of Hippo signaling in Drosophila POSH overexpression synergizes with loss of Kibra to induce overgrowth and up-regulation of Hippo pathway target genes. Furthermore, knockdown of POSH impedes dextran sulfate sodium-induced Yorkie-dependent intestinal stem cell renewal, suggesting a physiological role of POSH in modulating Hippo signaling. Mechanistically, POSH binds to the C-terminal of Ex and is essential for the Crumbs-induced ubiquitination and degradation of Ex. Our findings establish POSH as a crucial regulator that integrates the signal from the cell surface to negatively regulate Ex-mediated Hippo activation in Drosophila .

D-tyrosine negatively regulates melanin synthesis by competitively inhibiting tyrosinase activity.

PubMed

Park, Jisu; Jung, Hyejung; Kim, Kyuri; Lim, Kyung-Min; Kim, Ji-Young; Jho, Eek-Hoon; Oh, Eok-Soo

2018-05-01

Although L-tyrosine is well known for its melanogenic effect, the contribution of D-tyrosine to melanin synthesis was previously unexplored. Here, we reveal that, unlike L-tyrosine, D-tyrosine dose-dependently reduced the melanin contents of human MNT-1 melanoma cells and primary human melanocytes. In addition, 500 μM of D-tyrosine completely inhibited 10 μM L-tyrosine-induced melanogenesis, and both in vitro assays and L-DOPA staining MNT-1 cells showed that tyrosinase activity is reduced by D-tyrosine treatment. Thus, D-tyrosine appears to inhibit L-tyrosine-mediated melanogenesis by competitively inhibiting tyrosinase activity. Furthermore, we found that D-tyrosine inhibited melanogenesis induced by α-MSH treatment or UV irradiation, which are the most common environmental factors responsible for melanin synthesis. Finally, we confirmed that D-tyrosine reduced melanin synthesis in the epidermal basal layer of a 3D human skin model. Taken together, these data suggest that D-tyrosine negatively regulates melanin synthesis by inhibiting tyrosinase activity in melanocyte-derived cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Negative feedback regulation of human platelets via autocrine activation of the platelet-derived growth factor alpha-receptor.

PubMed

Vassbotn, F S; Havnen, O K; Heldin, C H; Holmsen, H

1994-05-13

Human platelets contain platelet-derived growth factor (PDGF) in their alpha-granules which is released during platelet exocytosis. We show by immunoprecipitation and 125I-PDGF binding experiments that human platelets have functionally active PDGF alpha-receptors, but not beta-receptors. The PDGF alpha-receptor (PDGFR-alpha) was identified as a 170-kDa glycosylated protein-tyrosine kinase as found in other cell types. Stimulation of platelets with 0.1 unit/ml thrombin resulted in a significant increase (2-5-fold) of the tyrosine phosphorylation of the PDGFR-alpha, as determined by immunoprecipitation with phosphotyrosine antiserum as well as with PDGFR-alpha antiserum. The observed thrombin-induced autophosphorylation of the PDGFR-alpha was inhibited by the addition of a neutralizing monoclonal PDGF antibody. Thus, our results suggest that the platelet PDGFR-alpha is stimulated in an autocrine manner by PDGF secreted during platelet activation. Preincubation of platelets with PDGF inhibited thrombin-induced platelet aggregation and secretion of ATP + ADP and beta-hexosaminidase. Thrombin-induced platelet aggregation was also reversed when PDGF was added 30 s after thrombin stimulation. Inhibition of the autocrine PDGF pathway during platelet activation by the PDGF antibody led to a potentiation of thrombin-induced beta-hexosaminidase secretion. Thus, the PDGFR-alpha takes part in a negative feedback regulation during platelet activation. Our demonstration of PDGF alpha-receptors on human platelets and its inhibitory function during platelet activation identifies a new possible role of PDGF in the regulation of thrombosis.

Rgs1 regulates multiple Gα subunits in Magnaporthe pathogenesis, asexual growth and thigmotropism

PubMed Central

Liu, Hao; Suresh, Angayarkanni; Willard, Francis S; Siderovski, David P; Lu, Shen; Naqvi, Naweed I

2007-01-01

Regulators of G-protein signaling (RGS proteins) negatively regulate heterotrimeric G-protein cascades that enable eukaryotic cells to perceive and respond to external stimuli. The rice-blast fungus Magnaporthe grisea forms specialized infection structures called appressoria in response to inductive surface cues. We isolated Magnaporthe RGS1 in a screen for mutants that form precocious appressoria on non-inductive surfaces. We report that a thigmotropic cue is necessary for initiating appressoria and for accumulating cAMP. Similar to an RGS1-deletion strain, magAG187S (RGS-insensitive Gαs) and magAQ208L (GTPase-dead) mutants accumulated excessive cAMP and elaborated appressoria on non-inductive surfaces, suggesting that Rgs1 regulates MagA during pathogenesis. Rgs1 was also found to negatively regulate the Gαi subunit MagB during asexual development. Deficiency of MAGB suppressed the hyper-conidiation defect in RGS1-deletion strain, whereas magBG183S and magBQ204L mutants produced more conidia, similar to the RGS1-deletion strain. Rgs1 physically interacted with GDP·AlF4−-activated forms of MagA, MagB and MagC (a GαII subunit). Thus, Rgs1 serves as a negative regulator of all Gα subunits in Magnaporthe and controls important developmental events during asexual and pathogenic development. PMID:17255942

Disruption of Abscisic Acid Signaling Constitutively Activates Arabidopsis Resistance to the Necrotrophic Fungus Plectosphaerella cucumerina1[W

PubMed Central

Sánchez-Vallet, Andrea; López, Gemma; Ramos, Brisa; Delgado-Cerezo, Magdalena; Riviere, Marie-Pierre; Llorente, Francisco; Fernández, Paula Virginia; Miedes, Eva; Estevez, José Manuel; Grant, Murray; Molina, Antonio

2012-01-01

Plant resistance to necrotrophic fungi is regulated by a complex set of signaling pathways that includes those mediated by the hormones salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and abscisic acid (ABA). The role of ABA in plant resistance remains controversial, as positive and negative regulatory functions have been described depending on the plant-pathogen interaction analyzed. Here, we show that ABA signaling negatively regulates Arabidopsis (Arabidopsis thaliana) resistance to the necrotrophic fungus Plectosphaerella cucumerina. Arabidopsis plants impaired in ABA biosynthesis, such as the aba1-6 mutant, or in ABA signaling, like the quadruple pyr/pyl mutant (pyr1pyl1pyl2pyl4), were more resistant to P. cucumerina than wild-type plants. In contrast, the hab1-1abi1-2abi2-2 mutant impaired in three phosphatases that negatively regulate ABA signaling displayed an enhanced susceptibility phenotype to this fungus. Comparative transcriptomic analyses of aba1-6 and wild-type plants revealed that the ABA pathway negatively regulates defense genes, many of which are controlled by the SA, JA, or ET pathway. In line with these data, we found that aba1-6 resistance to P. cucumerina was partially compromised when the SA, JA, or ET pathway was disrupted in this mutant. Additionally, in the aba1-6 plants, some genes encoding cell wall-related proteins were misregulated. Fourier transform infrared spectroscopy and biochemical analyses of cell walls from aba1-6 and wild-type plants revealed significant differences in their Fourier transform infrared spectratypes and uronic acid and cellulose contents. All these data suggest that ABA signaling has a complex function in Arabidopsis basal resistance, negatively regulating SA/JA/ET-mediated resistance to necrotrophic fungi. PMID:23037505

Ionizing radiation induces cellular senescence of articular chondrocytes via negative regulation of SIRT1 by p38 kinase.

PubMed

Hong, Eun-Hee; Lee, Su-Jae; Kim, Jae-Sung; Lee, Kee-Ho; Um, Hong-Duck; Kim, Jae-Hong; Kim, Song-Ja; Kim, Jong-Il; Hwang, Sang-Gu

2010-01-08

Radiotherapy is increasingly used in the treatment of joint diseases, but limited information is available on the effects of radiation on cartilage. Here, we characterize the molecular mechanisms leading to cellular senescence in irradiated primary cultured articular chondrocytes. Ionizing radiation (IR) causes activation of ERK, in turn generating intracellular reactive oxygen species (ROS) with induction of senescence-associated beta-galactosidase (SA-beta-gal) activity. ROS activate p38 kinase, which further promotes ROS generation, forming a positive feedback loop to sustain ROS-p38 kinase signaling. The ROS inhibitors, nordihydroguaiaretic acid and GSH, suppress phosphorylation of p38 and cell numbers positive for SA-beta-gal following irradiation. Moreover, inhibition of the ERK and p38 kinase pathways leads to blockage of IR-induced SA-beta-gal activity via reduction of ROS generation. Although JNK is activated by ROS, this pathway is not associated with cellular senescence of chondrocytes. Interestingly, IR triggers down-regulation of SIRT1 protein expression but not the transcript level, indicative of post-transcriptional cleavage of the protein. SIRT1 degradation is markedly blocked by SB203589 or MG132 after IR treatment, suggesting that cleavage occurs as a result of binding with p38 kinase, followed by processing via the 26 S proteasomal degradation pathway. Overexpression or activation of SIRT1 significantly reduces the IR-induced senescence phenotype, whereas inhibition of SIRT1 activity induces senescence. Based on these findings, we propose that IR induces cellular senescence of articular chondrocytes by negative post-translational regulation of SIRT1 via ROS-dependent p38 kinase activation.

The impact of verbal framing on brain activity evoked by emotional images.

PubMed

Kisley, Michael A; Campbell, Alana M; Larson, Jenna M; Naftz, Andrea E; Regnier, Jesse T; Davalos, Deana B

2011-12-01

Emotional stimuli generally command more brain processing resources than non-emotional stimuli, but the magnitude of this effect is subject to voluntary control. Cognitive reappraisal represents one type of emotion regulation that can be voluntarily employed to modulate responses to emotional stimuli. Here, the late positive potential (LPP), a specific event-related brain potential (ERP) component, was measured in response to neutral, positive and negative images while participants performed an evaluative categorization task. One experimental group adopted a "negative frame" in which images were categorized as negative or not. The other adopted a "positive frame" in which the exact same images were categorized as positive or not. Behavioral performance confirmed compliance with random group assignment, and peak LPP amplitude to negative images was affected by group membership: brain responses to negative images were significantly reduced in the "positive frame" group. This suggests that adopting a more positive appraisal frame can modulate brain activity elicited by negative stimuli in the environment.

Blue-light-induced PIN3 polarization for root negative phototropic response in Arabidopsis.

PubMed

Zhang, Kun-Xiao; Xu, Heng-Hao; Yuan, Ting-Ting; Zhang, Liang; Lu, Ying-Tang

2013-10-01

Root negative phototropism is an important response in plants. Although blue light is known to mediate this response, the cellular and molecular mechanisms underlying root negative phototropism remain unclear. Here, we report that the auxin efflux carrier PIN-FORMED (PIN) 3 is involved in asymmetric auxin distribution and root negative phototropism. Unilateral blue-light illumination polarized PIN3 to the outer lateral membrane of columella cells at the illuminated root side, and increased auxin activity at the illuminated side of roots, where auxin promotes growth and causes roots bending away from the light source. Furthermore, root negative phototropic response and blue-light-induced PIN3 polarization were modulated by a brefeldin A-sensitive, GNOM-dependent, trafficking pathway and by phot1-regulated PINOID (PID)/PROTEIN PHOSPHATASE 2A (PP2A) activity. Our results indicate that blue-light-induced PIN3 polarization is needed for asymmetric auxin distribution during root negative phototropic response. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Negative role of RIG-I serine 8 phosphorylation in the regulation of interferon-beta production.

PubMed

Nistal-Villán, Estanislao; Gack, Michaela U; Martínez-Delgado, Gustavo; Maharaj, Natalya P; Inn, Kyung-Soo; Yang, Heyi; Wang, Rong; Aggarwal, Aneel K; Jung, Jae U; García-Sastre, Adolfo

2010-06-25

RIG-I (retinoic acid-inducible gene I) and TRIM25 (tripartite motif protein 25) have emerged as key regulatory factors to induce interferon (IFN)-mediated innate immune responses to limit viral replication. Upon recognition of viral RNA, TRIM25 E3 ligase binds the first caspase recruitment domain (CARD) of RIG-I and subsequently induces lysine 172 ubiquitination of the second CARD of RIG-I, which is essential for the interaction with downstream MAVS/IPS-1/CARDIF/VISA and, thereby, IFN-beta mRNA production. Although ubiquitination has emerged as a major factor involved in RIG-I activation, the potential contribution of other post-translational modifications, such as phosphorylation, to the regulation of RIG-I activity has not been addressed. Here, we report the identification of serine 8 phosphorylation at the first CARD of RIG-I as a negative regulatory mechanism of RIG-I-mediated IFN-beta production. Immunoblot analysis with a phosphospecific antibody showed that RIG-I serine 8 phosphorylation steady-state levels were decreased upon stimulation of cells with IFN-beta or virus infection. Substitution of serine 8 in the CARD RIG-I functional domain with phosphomimetic aspartate or glutamate results in decreased TRIM25 binding, RIG-I ubiquitination, MAVS binding, and downstream signaling. Finally, sequence comparison reveals that only primate species carry serine 8, whereas other animal species carry an asparagine, indicating that serine 8 phosphorylation may represent a primate-specific regulation of RIG-I activation. Collectively, these data suggest that the phosphorylation of RIG-I serine 8 operates as a negative switch of RIG-I activation by suppressing TRIM25 interaction, further underscoring the importance of RIG-I and TRIM25 connection in type I IFN signal transduction.

The Arabidopsis Chaperone J3 Regulates the Plasma Membrane H+-ATPase through Interaction with the PKS5 Kinase[C][W

PubMed Central

Yang, Yongqing; Qin, Yunxia; Xie, Changgen; Zhao, Feiyi; Zhao, Jinfeng; Liu, Dafa; Chen, Shouyi; Fuglsang, Anja T.; Palmgren, Michael G.; Schumaker, Karen S.; Deng, Xing Wang; Guo, Yan

2010-01-01

The plasma membrane H+-ATPase (PM H+-ATPase) plays an important role in the regulation of ion and metabolite transport and is involved in physiological processes that include cell growth, intracellular pH, and stomatal regulation. PM H+-ATPase activity is controlled by many factors, including hormones, calcium, light, and environmental stresses like increased soil salinity. We have previously shown that the Arabidopsis thaliana Salt Overly Sensitive2-Like Protein Kinase5 (PKS5) negatively regulates the PM H+-ATPase. Here, we report that a chaperone, J3 (DnaJ homolog 3; heat shock protein 40-like), activates PM H+-ATPase activity by physically interacting with and repressing PKS5 kinase activity. Plants lacking J3 are hypersensitive to salt at high external pH and exhibit decreased PM H+-ATPase activity. J3 functions upstream of PKS5 as double mutants generated using j3-1 and several pks5 mutant alleles with altered kinase activity have levels of PM H+-ATPase activity and responses to salt at alkaline pH similar to their corresponding pks5 mutant. Taken together, our results demonstrate that regulation of PM H+-ATPase activity by J3 takes place via inactivation of the PKS5 kinase. PMID:20418496

The RNA-binding Protein TDP-43 Selectively Disrupts MicroRNA-1/206 Incorporation into the RNA-induced Silencing Complex*♦

PubMed Central

King, Isabelle N.; Yartseva, Valeria; Salas, Donaldo; Kumar, Abhishek; Heidersbach, Amy; Ando, D. Michael; Stallings, Nancy R.; Elliott, Jeffrey L.; Srivastava, Deepak; Ivey, Kathryn N.

2014-01-01

MicroRNA (miRNA) maturation is regulated by interaction of particular miRNA precursors with specific RNA-binding proteins. Following their biogenesis, mature miRNAs are incorporated into the RNA-induced silencing complex (RISC) where they interact with mRNAs to negatively regulate protein production. However, little is known about how mature miRNAs are regulated at the level of their activity. To address this, we screened for proteins differentially bound to the mature form of the miR-1 or miR-133 miRNA families. These muscle-enriched, co-transcribed miRNA pairs cooperate to suppress smooth muscle gene expression in the heart. However, they also have opposing roles, with the miR-1 family, composed of miR-1 and miR-206, promoting myogenic differentiation, whereas miR-133 maintains the progenitor state. Here, we describe a physical interaction between TDP-43, an RNA-binding protein that forms aggregates in the neuromuscular disease, amyotrophic lateral sclerosis, and the miR-1, but not miR-133, family. Deficiency of the TDP-43 Drosophila ortholog enhanced dmiR-1 activity in vivo. In mammalian cells, TDP-43 limited the activity of both miR-1 and miR-206, but not the miR-133 family, by disrupting their RISC association. Consistent with TDP-43 dampening miR-1/206 activity, protein levels of the miR-1/206 targets, IGF-1 and HDAC4, were elevated in TDP-43 transgenic mouse muscle. This occurred without corresponding Igf-1 or Hdac4 mRNA increases and despite higher miR-1 and miR-206 expression. Our findings reveal that TDP-43 negatively regulates the activity of the miR-1 family of miRNAs by limiting their bioavailability for RISC loading and suggest a processing-independent mechanism for differential regulation of miRNA activity. PMID:24719334

The RNA-binding protein TDP-43 selectively disrupts microRNA-1/206 incorporation into the RNA-induced silencing complex.

PubMed

King, Isabelle N; Yartseva, Valeria; Salas, Donaldo; Kumar, Abhishek; Heidersbach, Amy; Ando, D Michael; Stallings, Nancy R; Elliott, Jeffrey L; Srivastava, Deepak; Ivey, Kathryn N

2014-05-16

MicroRNA (miRNA) maturation is regulated by interaction of particular miRNA precursors with specific RNA-binding proteins. Following their biogenesis, mature miRNAs are incorporated into the RNA-induced silencing complex (RISC) where they interact with mRNAs to negatively regulate protein production. However, little is known about how mature miRNAs are regulated at the level of their activity. To address this, we screened for proteins differentially bound to the mature form of the miR-1 or miR-133 miRNA families. These muscle-enriched, co-transcribed miRNA pairs cooperate to suppress smooth muscle gene expression in the heart. However, they also have opposing roles, with the miR-1 family, composed of miR-1 and miR-206, promoting myogenic differentiation, whereas miR-133 maintains the progenitor state. Here, we describe a physical interaction between TDP-43, an RNA-binding protein that forms aggregates in the neuromuscular disease, amyotrophic lateral sclerosis, and the miR-1, but not miR-133, family. Deficiency of the TDP-43 Drosophila ortholog enhanced dmiR-1 activity in vivo. In mammalian cells, TDP-43 limited the activity of both miR-1 and miR-206, but not the miR-133 family, by disrupting their RISC association. Consistent with TDP-43 dampening miR-1/206 activity, protein levels of the miR-1/206 targets, IGF-1 and HDAC4, were elevated in TDP-43 transgenic mouse muscle. This occurred without corresponding Igf-1 or Hdac4 mRNA increases and despite higher miR-1 and miR-206 expression. Our findings reveal that TDP-43 negatively regulates the activity of the miR-1 family of miRNAs by limiting their bioavailability for RISC loading and suggest a processing-independent mechanism for differential regulation of miRNA activity. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

VAV-1 acts in a single interneuron to inhibit motor circuit activity in Caenorhabditis elegans.

PubMed

Fry, Amanda L; Laboy, Jocelyn T; Norman, Kenneth R

2014-11-21

The complex molecular and cellular mechanisms underlying neuronal control of animal movement are not well understood. Locomotion of Caenorhabditis elegans is mediated by a neuronal circuit that produces coordinated sinusoidal movement. Here we utilize this simple, yet elegant, behaviour to show that VAV-1, a conserved guanine nucleotide exchange factor for Rho-family GTPases, negatively regulates motor circuit activity and the rate of locomotion. While vav-1 is expressed in a small subset of neurons, we find that VAV-1 function is required in a single interneuron, ALA, to regulate motor neuron circuit activity. Furthermore, we show by genetic and optogenetic manipulation of ALA that VAV-1 is required for the excitation and activation of this neuron. We find that ALA signalling inhibits command interneuron activity by abrogating excitatory signalling in the command interneurons, which is responsible for promoting motor neuron circuit activity. Together, our data describe a novel neuromodulatory role for VAV-1-dependent signalling in the regulation of motor circuit activity and locomotion.

Negative feedback via RSK modulates Erk-dependent progression from naïve pluripotency.

PubMed

Nett, Isabelle Re; Mulas, Carla; Gatto, Laurent; Lilley, Kathryn S; Smith, Austin

2018-06-12

Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signalling is implicated in initiation of embryonic stem (ES) cell differentiation. The pathway is subject to complex feedback regulation. Here, we examined the ERK-responsive phosphoproteome in ES cells and identified the negative regulator RSK1 as a prominent target. We used CRISPR/Cas9 to create combinatorial mutations in RSK family genes. Genotypes that included homozygous null mutations in Rps6ka1, encoding RSK1, resulted in elevated ERK phosphorylation. These RSK-depleted ES cells exhibit altered kinetics of transition into differentiation, with accelerated downregulation of naïve pluripotency factors, precocious expression of transitional epiblast markers and early onset of lineage specification. We further show that chemical inhibition of RSK increases ERK phosphorylation and expedites ES cell transition without compromising multilineage potential. These findings demonstrate that the ERK activation profile influences the dynamics of pluripotency progression and highlight the role of signalling feedback in temporal control of cell state transitions. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Alternative mechanisms for regulating racial responses according to internal vs external cues.

PubMed

Amodio, David M; Kubota, Jennifer T; Harmon-Jones, Eddie; Devine, Patricia G

2006-06-01

Personal (internal) and normative (external) impetuses for regulating racially biased behaviour are well-documented, yet the extent to which internally and externally driven regulatory processes arise from the same mechanism is unknown. Whereas the regulation of race bias according to internal cues has been associated with conflict-monitoring processes and activation of the dorsal anterior cingulate cortex (dACC), we proposed that responses regulated according to external cues to respond without prejudice involves mechanisms of error-perception, a process associated with rostral anterior cingulate cortex (rACC) activity. We recruited low-prejudice participants who reported high or low sensitivity to non-prejudiced norms, and participants completed a stereotype inhibition task in private or public while electroencephalography was recorded. Analysis of event-related potentials revealed that the error-related negativity component, linked to dACC activity, predicted behavioural control of bias across conditions, whereas the error-perception component, linked to rACC activity, predicted control only in public among participants sensitive to external pressures to respond without prejudice.

Individual differences in cognitive reappraisal use and emotion regulatory brain function in combat-exposed veterans with and without PTSD.

PubMed

Fitzgerald, Jacklynn M; MacNamara, Annmarie; Kennedy, Amy E; Rabinak, Christine A; Rauch, Sheila A M; Liberzon, Israel; Phan, K Luan

2017-01-01

Veterans with posttraumatic stress disorder (PTSD) exhibit marked deficits in emotion regulation. Past research has demonstrated underengagement of the prefrontal cortex during regulation of negative affect in those with PTSD, but has been unable to find evidence of impaired downregulation of the amygdala. One possibility is that there exists variability in amygdala reactivity that cuts across diagnostic status and which can be characterized using a continuous measure of individual differences. In healthy/nontraumatized volunteers, individual variability in amygdala engagement during emotion processing and regulation has been shown to relate to habitual use of regulation strategies. The current study examined whether self-reported use of cognitive reappraisal and expressive suppression regulation strategies correlated with brain activation during cognitive reappraisal in combat-exposed veterans with (n = 28) and without PTSD (combat-exposed controls, CEC; n = 20). Results showed that greater self-reported use of cognitive reappraisal was associated with less activation in the right amygdala during volitional attempts to attenuate negative affect using reappraisal, irrespective of PTSD diagnosis. This finding is in line with prior work and extends evidence of an association between habitual use of regulation strategies and amygdala engagement during emotion regulation to a trauma-exposed sample of individuals both with and without PTSD. Furthermore, by providing evidence of individual differences in regulation-related amygdala response in a traumatized sample, this result may increase understanding of the neural mechanisms that support variability in symptom manifestation observed across individuals with PTSD. © 2016 Wiley Periodicals, Inc.

Associations between children's video game playing and psychosocial health: Information from both parent and child reports. [corrected].

PubMed

Lobel, Adam; Granic, Isabela; Engels, Rutger C M E

2014-04-01

Healthy emotion regulation is crucial for navigating stressful situations. Interoceptive awareness-the awareness of one's internal states-is important for such healthy regulation. Given the propensity for video games to induce stress, the associations between in-game and real world emotion regulation strategies during duress are worth exploring. We therefore present a method for measuring the interoceptive awareness of negative affect during stressful video game play, and investigate whether individual differences in this ability relate to emotion regulation strategies. Twenty-six proficient video game players were recruited to play a session of the video game Starcraft II in the lab. Players' physiological and subjective states of in-game negative arousal were measured consecutively. A comparison of these measures was used to calculate players' interoceptive awareness of real time in-game arousal. The relation between interoceptive awareness and a suite of emotion regulation strategies was then investigated. We observed a positive relation between in-game interoceptive awareness and the self-reported tendency to actively seek a resolution to negative affect. A positive trend was also observed between interoceptive awareness and the self-reported tendency to seek instrumental social support. Findings are discussed in terms of the relative effectiveness of different emotion regulation strategies for aiding in-game success. We further discuss the benefits and limitations of this pilot testing. In all, we hope to inspire future research into the associations between in-game arousal and emotion regulation strategies used in everyday life.

Basic helix-loop-helix transcription factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 are negative regulators of jasmonate responses in Arabidopsis.

PubMed

Sasaki-Sekimoto, Yuko; Jikumaru, Yusuke; Obayashi, Takeshi; Saito, Hikaru; Masuda, Shinji; Kamiya, Yuji; Ohta, Hiroyuki; Shirasu, Ken

2013-09-01

Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2.

Basic Helix-Loop-Helix Transcription Factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 Are Negative Regulators of Jasmonate Responses in Arabidopsis1[W][OPEN

PubMed Central

Sasaki-Sekimoto, Yuko; Jikumaru, Yusuke; Obayashi, Takeshi; Saito, Hikaru; Masuda, Shinji; Kamiya, Yuji; Ohta, Hiroyuki; Shirasu, Ken

2013-01-01

Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2. PMID:23852442

Extreme positive and negative appraisals of activated states interact to discriminate bipolar disorder from unipolar depression and non-clinical controls.

PubMed

Kelly, Rebecca E; Mansell, Warren; Wood, Alex M; Alatiq, Yousra; Dodd, Alyson; Searson, Ruth

2011-11-01

This research aimed to test whether positive, negative, or conflicting appraisals about activated mood states (e.g., energetic and high states) predicted bipolar disorder. A sample of individuals from clinical and control groups (171 with bipolar disorder, 42 with unipolar depression, and 64 controls) completed a measure of appraisals of internal states. High negative appraisals related to a higher likelihood of bipolar disorder irrespective of positive appraisals. High positive appraisals related to a higher likelihood of bipolar disorder only when negative appraisals were also high. Individuals were most likely to have bipolar disorder, as opposed to unipolar depression or no diagnosis, when they endorsed both extremely positive and extremely negative appraisals of the same, activated states. Appraisals of internal states were based on self-report. The results indicate that individuals with bipolar disorder tend to appraise activated, energetic internal states in opposing or conflicting ways, interpreting these states as both extremely positive and extremely negative. This may lead to contradictory attempts to regulate these states, which may in turn contribute to mood swing symptoms. Psychological therapy for mood swings and bipolar disorder should address extreme and conflicting appraisals of mood states. Copyright © 2011 Elsevier B.V. All rights reserved.

Duodenal mucosal protein kinase C-δ regulates glucose production in rats.

PubMed

Kokorovic, Andrea; Cheung, Grace W C; Breen, Danna M; Chari, Madhu; Lam, Carol K L; Lam, Tony K T

2011-11-01

Activation of protein kinase C (PKC) enzymes in liver and brain alters hepatic glucose metabolism, but little is known about their role in glucose regulation in the gastrointestinal tract. We investigated whether activation of PKC-δ in the duodenum is sufficient and necessary for duodenal nutrient sensing and regulates hepatic glucose production through a neuronal network in rats. In rats, we inhibited duodenal PKC and evaluated whether nutrient-sensing mechanisms, activated by refeeding, have disruptions in glucose regulation. We then performed gain- and loss-of-function pharmacologic and molecular experiments to target duodenal PKC-δ; we evaluated the impact on glucose production regulation during the pancreatic clamping, while basal levels of insulin were maintained. PKC-δ was detected in the mucosal layer of the duodenum; intraduodenal infusion of PKC inhibitors disrupted glucose homeostasis during refeeding, indicating that duodenal activation of PKC-δ is necessary and sufficient to regulate glucose homeostasis. Intraduodenal infusion of the PKC activator 1-oleoyl-2-acetyl-sn-glycerol (OAG) specifically activated duodenal mucosal PKC-δ and a gut-brain-liver neuronal pathway to reduce glucose production. Molecular and pharmacologic inhibition of duodenal mucosal PKC-δ negated the ability of duodenal OAG and lipids to reduce glucose production. In the duodenal mucosa, PKC-δ regulates glucose homeostasis. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

Neuropilins are positive regulators of Hedgehog signal transduction

PubMed Central

Hillman, R. Tyler; Feng, Brian Y.; Ni, Jun; Woo, Wei-Meng; Milenkovic, Ljiljana; Hayden Gephart, Melanie G.; Teruel, Mary N.; Oro, Anthony E.; Chen, James K.; Scott, Matthew P.

2011-01-01

The Hedgehog (Hh) pathway is essential for vertebrate embryogenesis, and excessive Hh target gene activation can cause cancer in humans. Here we show that Neuropilin 1 (Nrp1) and Nrp2, transmembrane proteins with roles in axon guidance and vascular endothelial growth factor (VEGF) signaling, are important positive regulators of Hh signal transduction. Nrps are expressed at times and locations of active Hh signal transduction during mouse development. Using cell lines lacking key Hh pathway components, we show that Nrps mediate Hh transduction between activated Smoothened (Smo) protein and the negative regulator Suppressor of Fused (SuFu). Nrp1 transcription is induced by Hh signaling, and Nrp1 overexpression increases maximal Hh target gene activation, indicating the existence of a positive feedback circuit. The regulation of Hh signal transduction by Nrps is conserved between mammals and bony fish, as we show that morpholinos targeting the Nrp zebrafish ortholog nrp1a produce a specific and highly penetrant Hh pathway loss-of-function phenotype. These findings enhance our knowledge of Hh pathway regulation and provide evidence for a conserved nexus between Nrps and this important developmental signaling system. PMID:22051878

Dual Role for Hsc70 in the Biogenesis and Regulation of the Heme-Regulated Kinase of the α Subunit of Eukaryotic Translation Initiation Factor 2

PubMed Central

Uma, Sheri; Thulasiraman, Vanitha; Matts, Robert L.

1999-01-01

The heme-regulated kinase of the α subunit of eukaryotic initiation factor 2 (HRI) is activated in rabbit reticulocyte lysate (RRL) in response to a number of environmental conditions, including heme deficiency, heat shock, and oxidative stress. Activation of HRI causes an arrest of initiation of protein synthesis. Recently, we have demonstrated that the heat shock cognate protein Hsc70 negatively modulates the activation of HRI in RRL in response to these environmental conditions. Hsc70 is also known to be a critical component of the Hsp90 chaperone machinery in RRL, which plays an obligatory role for HRI to acquire and maintain a conformation that is competent to activate. Using de novo-synthesized HRI in synchronized pulse-chase translations, we have examined the role of Hsc70 in the regulation of HRI biogenesis and activation. Like Hsp90, Hsc70 interacted with nascent HRI and HRI that was matured to a state which was competent to undergo stimulus-induced activation (mature-competent HRI). Interaction of HRI with Hsc70 was required for the transformation of HRI, as the Hsc70 antagonist clofibric acid inhibited the folding of HRI into a mature-competent conformation. Unlike Hsp90, Hsc70 also interacted with transformed HRI. Clofibric acid disrupted the interaction of Hsc70 with transformed HRI that had been matured and transformed in the absence of the drug. Disruption of Hsc70 interaction with transformed HRI in heme-deficient RRL resulted in its hyperactivation. Furthermore, activation of HRI in response to heat shock or denatured proteins also resulted in a similar blockage of Hsc70 interaction with transformed HRI. These results indicate that Hsc70 is required for the folding and transformation of HRI into an active kinase but is subsequently required to negatively attenuate the activation of transformed HRI. PMID:10454533

Individual differences in self-reported self-control predict successful emotion regulation

PubMed Central

Dörfel, Denise; Steimke, Rosa; Trempler, Ima; Magrabi, Amadeus; Ludwig, Vera U.; Schubert, Torsten; Stelzel, Christine; Walter, Henrik

2016-01-01

Both self-control and emotion regulation enable individuals to adapt to external circumstances and social contexts, and both are assumed to rely on the overlapping neural resources. Here, we tested whether high self-reported self-control is related to successful emotion regulation on the behavioral and neural level. One hundred eight participants completed three self-control questionnaires and regulated their negative emotions during functional magnetic resonance imaging using reappraisal (distancing). Trait self-control correlated positively with successful emotion regulation both subjectively and neurally, as indicated by online ratings of negative emotions and functional connectivity strength between the amygdala and prefrontal areas, respectively. This stronger overall connectivity of the left amygdala was related to more successful subjective emotion regulation. Comparing amygdala activity over time showed that high self-controllers successfully maintained down-regulation of the left amygdala over time, while low self-controllers failed to down-regulate towards the end of the experiment. This indicates that high self-controllers are better at maintaining a motivated state supporting emotion regulation over time. Our results support assumptions concerning a close relation of self-control and emotion regulation as two domains of behavioral control. They further indicate that individual differences in functional connectivity between task-related brain areas directly relate to differences in trait self-control. PMID:27013102

The QTL GNP1 Encodes GA20ox1, Which Increases Grain Number and Yield by Increasing Cytokinin Activity in Rice Panicle Meristems.

PubMed

Wu, Yuan; Wang, Yun; Mi, Xue-Fei; Shan, Jun-Xiang; Li, Xin-Min; Xu, Jian-Long; Lin, Hong-Xuan

2016-10-01

Cytokinins and gibberellins (GAs) play antagonistic roles in regulating reproductive meristem activity. Cytokinins have positive effects on meristem activity and maintenance. During inflorescence meristem development, cytokinin biosynthesis is activated via a KNOX-mediated pathway. Increased cytokinin activity leads to higher grain number, whereas GAs negatively affect meristem activity. The GA biosynthesis genes GA20oxs are negatively regulated by KNOX proteins. KNOX proteins function as modulators, balancing cytokinin and GA activity in the meristem. However, little is known about the crosstalk among cytokinin and GA regulators together with KNOX proteins and how KNOX-mediated dynamic balancing of hormonal activity functions. Through map-based cloning of QTLs, we cloned a GA biosynthesis gene, Grain Number per Panicle1 (GNP1), which encodes rice GA20ox1. The grain number and yield of NIL-GNP1TQ were significantly higher than those of isogenic control (Lemont). Sequence variations in its promoter region increased the levels of GNP1 transcripts, which were enriched in the apical regions of inflorescence meristems in NIL-GNP1TQ. We propose that cytokinin activity increased due to a KNOX-mediated transcriptional feedback loop resulting from the higher GNP1 transcript levels, in turn leading to increased expression of the GA catabolism genes GA2oxs and reduced GA1 and GA3 accumulation. This rebalancing process increased cytokinin activity, thereby increasing grain number and grain yield in rice. These findings uncover important, novel roles of GAs in rice florescence meristem development and provide new insights into the crosstalk between cytokinin and GA underlying development process.

Antimicrobial activity-specific to Gram-negative bacteria and immune modulation-mediated NF-kappaB and Sp1 of a medaka beta-defensin.

PubMed

Zhao, Jiu-Gang; Zhou, Li; Jin, Jun-Yan; Zhao, Zhe; Lan, Jing; Zhang, Yi-Bin; Zhang, Qi-Ya; Gui, Jian-Fang

2009-04-01

Defensins are a group of cationic antimicrobial peptides which play an important role in the innate immune system by exerting their antimicrobial activity against pathogens. In this study, we cloned a novel beta-defensin cDNA from medaka (Oryzias latipes) by rapid amplification of cDNA ends (RACE) technique. The full-length cDNA consists of 480 bp, and the open reading frame (ORF) of 189 bp encodes a polypeptide of 63 amino acids (aa) with a predicted molecular weight of 7.44 kDa. Its genomic organization was analyzed, and Southern blot detection confirmed that only one copy of beta-defensin exists in the medaka HNI strain. RT-PCR, Western blot and immunohistochemistry detections showed that the beta-defensin transcript and protein could be detected in eyes, liver, kidney, blood, spleen and gill, and obviously prevalent expression was found in eyes. Antimicrobial activity of the medaka beta-defensin was evaluated, and the antibacterial activity-specific to Gram-negative bacteria was revealed. Furthermore, the lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, was demonstrated to be able to induce about 13-fold up-regulation of the beta-defensin within first 12h. In addition, promoter and promoter mutagenesis analysis were performed in the medaka beta-defensin. A proximal 100 base pair (bp) sequence (+26 to -73) and the next 1700 bp sequence (-73 to -1755) were demonstrated to be responsible for the basal promoter activity and for the transcription regulation. Three nuclear factor kappa B (NF-kappaB) cis-elements and a Sp1 cis-element were revealed by mutagenesis analysis to exist in the 5' flanking sequence, and they were confirmed to be responsible for the up-regulation of medaka beta-defensin stimulated by LPS. And, the Sp1 cis-element was further revealed to be related to the basal promoter activity, and transcriptional factor II D (TFIID) was found to be in charge of the gene transcription initiation. All the obtained data suggested that the novel medaka beta-defensin should have antimicrobial activity-specific to Gram-negative bacteria, and the antibacterial immune function should be modulated by NF-kappaB and Sp1.

Relationship between serum response factor and androgen receptor in prostate cancer.

PubMed

Prencipe, Maria; O'Neill, Amanda; O'Hurley, Gillian; Nguyen, Lan K; Fabre, Aurelie; Bjartell, Anders; Gallagher, William M; Morrissey, Colm; Kay, Elaine W; Watson, R William

2015-11-01

Serum response factor (SRF) is an important transcription factor in castrate-resistant prostate cancer (CRPC). Since CRPC is associated with androgen receptor (AR) hypersensitivity, we investigated the relationship between SRF and AR. Transcriptional activity was assessed by luciferase assay. Cell proliferation was measured by MTT and flow cytometry. Protein expression in patients was assessed by immunohistochemistry. To investigate AR involvement in SRF response to androgen, AR expression was down-regulated using siRNA. This resulted in the abrogation of SRF induction post-DHT. Moreover, DHT stimulation failed to induce SRF transcriptional activity in AR-negative PC346 DCC cells, which was only restored following AR over-expression. Next, SRF expression was down-regulated by siRNA, resulting in AR increased transcriptional activity in castrate-resistant LNCaP Abl cells but not in the parental LNCaP. This negative feedback loop in the resistant cells was confirmed by immunohistochemistry which showed a negative correlation between AR and SRF expression in CRPC bone metastases and a positive correlation in androgen-naïve prostatectomies. Cell proliferation was next assessed following SRF inhibition, demonstrating that SRF inhibition is more effective than AR inhibition in castrate-resistant cells. Our data support SRF as a promising therapeutic target in combination with current treatments. © 2015 Wiley Periodicals, Inc.

mTORC1 Is a Local, Postsynaptic Voltage Sensor Regulated by Positive and Negative Feedback Pathways

PubMed Central

Niere, Farr; Raab-Graham, Kimberly F.

2017-01-01

The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) serves as a regulator of mRNA translation. Recent studies suggest that mTORC1 may also serve as a local, voltage sensor in the postsynaptic region of neurons. Considering biochemical, bioinformatics and imaging data, we hypothesize that the activity state of mTORC1 dynamically regulates local membrane potential by promoting and repressing protein synthesis of select mRNAs. Our hypothesis suggests that mTORC1 uses positive and negative feedback pathways, in a branch-specific manner, to maintain neuronal excitability within an optimal range. In some dendritic branches, mTORC1 activity oscillates between the “On” and “Off” states. We define this as negative feedback. In contrast, positive feedback is defined as the pathway that leads to a prolonged depolarized or hyperpolarized resting membrane potential, whereby mTORC1 activity is constitutively on or off, respectively. We propose that inactivation of mTORC1 increases the expression of voltage-gated potassium alpha (Kv1.1 and 1.2) and beta (Kvβ2) subunits, ensuring that the membrane resets to its resting membrane potential after experiencing increased synaptic activity. In turn, reduced mTORC1 activity increases the protein expression of syntaxin-1A and promotes the surface expression of the ionotropic glutamate receptor N-methyl-D-aspartate (NMDA)-type subunit 1 (GluN1) that facilitates increased calcium entry to turn mTORC1 back on. Under conditions such as learning and memory, mTORC1 activity is required to be high for longer periods of time. Thus, the arm of the pathway that promotes syntaxin-1A and Kv1 protein synthesis will be repressed. Moreover, dendritic branches that have low mTORC1 activity with increased Kv expression would balance dendrites with constitutively high mTORC1 activity, allowing for the neuron to maintain its overall activity level within an ideal operating range. Finally, such a model suggests that recruitment of more positive feedback dendritic branches within a neuron is likely to lead to neurodegenerative disorders. PMID:28611595

TRIM25 in the Regulation of the Antiviral Innate Immunity

PubMed Central

Martín-Vicente, María; Medrano, Luz M.; Resino, Salvador; García-Sastre, Adolfo; Martínez, Isidoro

2017-01-01

TRIM25 is an E3 ubiquitin ligase enzyme that is involved in various cellular processes, including regulation of the innate immune response against viruses. TRIM25-mediated ubiquitination of the cytosolic pattern recognition receptor RIG-I is an essential step for initiation of the intracellular antiviral response and has been thoroughly documented. In recent years, however, additional roles of TRIM25 in early innate immunity are emerging, including negative regulation of RIG-I, activation of the melanoma differentiation-associated protein 5–mitochondrial antiviral signaling protein–TRAF6 antiviral axis and modulation of p53 levels and activity. In addition, the ability of TRIM25 to bind RNA may uncover new mechanisms by which this molecule regulates intracellular signaling and/or RNA virus replication. PMID:29018447

Neuronal regulation of homeostasis by nutrient sensing.

PubMed

Lam, Tony K T

2010-04-01

In type 2 diabetes and obesity, the homeostatic control of glucose and energy balance is impaired, leading to hyperglycemia and hyperphagia. Recent studies indicate that nutrient-sensing mechanisms in the body activate negative-feedback systems to regulate energy and glucose homeostasis through a neuronal network. Direct metabolic signaling within the intestine activates gut-brain and gut-brain-liver axes to regulate energy and glucose homeostasis, respectively. In parallel, direct metabolism of nutrients within the hypothalamus regulates food intake and blood glucose levels. These findings highlight the importance of the central nervous system in mediating the ability of nutrient sensing to maintain homeostasis. Futhermore, they provide a physiological and neuronal framework by which enhancing or restoring nutrient sensing in the intestine and the brain could normalize energy and glucose homeostasis in diabetes and obesity.

Emotion regulation in preschoolers: the roles of behavioral inhibition, maternal affective behavior, and maternal depression.

PubMed

Feng, Xin; Shaw, Daniel S; Kovacs, Maria; Lane, Tonya; O'Rourke, Flannery E; Alarcon, Joseph H

2008-02-01

This study examined preschoolers' emotion regulation (ER) strategies and the association with temperament, maternal interactive style, and maternal history of childhood-onset depression (COD). Participants were 62 children and their mothers, 37 of whom had mothers with COD. Children's ER was assessed using a disappointment paradigm; temperament assessment also was laboratory-based. Maternal COD was inversely related to offspring's active ER and positive mood. Among children of COD mothers, behavioral inhibition was associated with passive regulation and sadness, and maternal positivity toward these children was associated with child active ER and positive mood. Behavioral inhibition may place children of COD mothers at risk for developing maladaptive ways of regulating negative emotion, whereas mothers' positivity may serve as a protective factor for them.

Snf1 Phosphorylates Adenylate Cyclase and Negatively Regulates Protein Kinase A-dependent Transcription in Saccharomyces cerevisiae.

PubMed

Nicastro, Raffaele; Tripodi, Farida; Gaggini, Marco; Castoldi, Andrea; Reghellin, Veronica; Nonnis, Simona; Tedeschi, Gabriella; Coccetti, Paola

2015-10-09

In eukaryotes, nutrient availability and metabolism are coordinated by sensing mechanisms and signaling pathways, which influence a broad set of cellular functions such as transcription and metabolic pathways to match environmental conditions. In yeast, PKA is activated in the presence of high glucose concentrations, favoring fast nutrient utilization, shutting down stress responses, and boosting growth. On the contrary, Snf1/AMPK is activated in the presence of low glucose or alternative carbon sources, thus promoting an energy saving program through transcriptional activation and phosphorylation of metabolic enzymes. The PKA and Snf1/AMPK pathways share common downstream targets. Moreover, PKA has been reported to negatively influence the activation of Snf1/AMPK. We report a new cross-talk mechanism with a Snf1-dependent regulation of the PKA pathway. We show that Snf1 and adenylate cyclase (Cyr1) interact in a nutrient-independent manner. Moreover, we identify Cyr1 as a Snf1 substrate and show that Snf1 activation state influences Cyr1 phosphorylation pattern, cAMP intracellular levels, and PKA-dependent transcription. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

T cell receptor for antigen induces linker for activation of T cell–dependent activation of a negative signaling complex involving Dok-2, SHIP-1, and Grb-2

PubMed Central

Dong, Shen; Corre, Béatrice; Foulon, Eliane; Dufour, Evelyne; Veillette, André; Acuto, Oreste; Michel, Frédérique

2006-01-01

Adaptor proteins positively or negatively regulate the T cell receptor for antigen (TCR) signaling cascade. We report that after TCR stimulation, the inhibitory adaptor downstream of kinase (Dok)-2 and its homologue Dok-1 are involved in a multimolecular complex including the lipid phosphatase Src homology 2 domain–containing inositol polyphosphate 5′-phosphatase (SHIP)-1 and Grb-2 which interacts with the membrane signaling scaffold linker for activation of T cells (LAT). Knockdown of LAT and SHIP-1 expression indicated that SHIP-1 favored recruitment of Dok-2 to LAT. Knockdown of Dok-2 and Dok-1 revealed their negative control on Akt and, unexpectedly, on Zap-70 activation. Our findings support the view that Dok-1 and -2 are critical elements of a LAT-dependent negative feedback loop that attenuates early TCR signal. Dok-1 and -2 may therefore exert a critical role in shaping the immune response and as gatekeepers for T cell tolerance. PMID:17043143

A PI3-kinase-mediated negative feedback regulates neuronal excitability.

PubMed

Howlett, Eric; Lin, Curtis Chun-Jen; Lavery, William; Stern, Michael

2008-11-01

Use-dependent downregulation of neuronal activity (negative feedback) can act as a homeostatic mechanism to maintain neuronal activity at a particular specified value. Disruption of this negative feedback might lead to neurological pathologies, such as epilepsy, but the precise mechanisms by which this feedback can occur remain incompletely understood. At one glutamatergic synapse, the Drosophila neuromuscular junction, a mutation in the group II metabotropic glutamate receptor gene (DmGluRA) increased motor neuron excitability by disrupting an autocrine, glutamate-mediated negative feedback. We show that DmGluRA mutations increase neuronal excitability by preventing PI3 kinase (PI3K) activation and consequently hyperactivating the transcription factor Foxo. Furthermore, glutamate application increases levels of phospho-Akt, a product of PI3K signaling, within motor nerve terminals in a DmGluRA-dependent manner. Finally, we show that PI3K increases both axon diameter and synapse number via the Tor/S6 kinase pathway, but not Foxo. In humans, PI3K and group II mGluRs are implicated in epilepsy, neurofibromatosis, autism, schizophrenia, and other neurological disorders; however, neither the link between group II mGluRs and PI3K, nor the role of PI3K-dependent regulation of Foxo in the control of neuronal excitability, had been previously reported. Our work suggests that some of the deficits in these neurological disorders might result from disruption of glutamate-mediated homeostasis of neuronal excitability.

Structure of the second RRM domain of Nrd1, a fission yeast MAPK target RNA binding protein, and implication for its RNA recognition and regulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Ayaho; Kanaba, Teppei; Satoh, Ryosuke

Highlights: •Solution structure of the second RRM of Nrd1 was determined. •RNA binding site of the second RRM was estimated. •Regulatory mechanism of RNA binding by phosphorylation is discussed. -- Abstract: Negative regulator of differentiation 1 (Nrd1) is known as a negative regulator of sexual differentiation in fission yeast. Recently, it has been revealed that Nrd1 also regulates cytokinesis, in which physical separation of the cell is achieved by a contractile ring comprising many proteins including actin and myosin. Cdc4, a myosin II light chain, is known to be required for cytokinesis. Nrd1 binds and stabilizes Cdc4 mRNA, and therebymore » suppressing the cytokinesis defects of the cdc4 mutants. Interestingly, Pmk1 MAPK phosphorylates Nrd1, resulting in markedly reduced RNA binding activity. Furthermore, Nrd1 localizes to stress granules in response to various stresses, and Pmk1 phosphorylation enhances the localization. Nrd1 consists of four RRM domains, although the mechanism by which Pmk1 regulates the RNA binding activity of Nrd1 is unknown. In an effort to delineate the relationship between Nrd1 structure and function, we prepared each RNA binding domain of Nrd1 and examined RNA binding to chemically synthesized oligo RNA using NMR. The structure of the second RRM domain of Nrd1 was determined and the RNA binding site on the second RRM domain was mapped by NMR. A plausible mechanism pertaining to the regulation of RNA binding activity by phosphorylation is also discussed.« less

Myostatin signaling regulates Akt activity via the regulation of miR-486 expression.

PubMed

Hitachi, Keisuke; Nakatani, Masashi; Tsuchida, Kunihiro

2014-02-01

Myostatin, also known as growth and differentiation factor-8, is a pivotal negative regulator of skeletal muscle mass and reduces muscle protein synthesis by inhibiting the insulin-like growth factor-1 (IGF-1)/Akt/mammalian target of rapamycin (mTOR) pathway. However, the precise mechanism by which myostatin inhibits the IGF-1/Akt/mTOR pathway remains unclear. In this study, we investigated the global microRNA expression profile in myostatin knockout mice and identified miR-486, a positive regulator of the IGF-1/Akt pathway, as a novel target of myostatin signaling. In myostatin knockout mice, the expression level of miR-486 in skeletal muscle was significantly increased. In addition, we observed increased expression of the primary transcript of miR-486 (pri-miR-486) and Ankyrin 1.5 (Ank1.5), the host gene of miR-486, in myostatin knockout mice. In C2C12 cells, myostatin negatively regulated the expression of Ank1.5. Moreover, canonical myostatin signaling repressed the skeletal muscle-specific promoter activity of miR-486/Ank1.5. This repression was partially mediated by the E-box elements in the proximal region of the promoter. We also show that overexpression of miR-486 induced myotube hypertrophy in vitro and that miR-486 was essential to maintain skeletal muscle size both in vitro and in vivo. In addition, inhibition of miR-486 led to a decrease in Akt activity in C2C12 myotubes. Our findings indicate that miR-486 is one of the intermediary molecules connecting myostatin signaling and the IGF-1/Akt/mTOR pathway in the regulation of skeletal muscle size. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rac1 and Cdc42 GTPases regulate shear stress-driven β-catenin signaling in osteoblasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan, Qiaoqiao; Cho, Eunhye; Yokota, Hiroki

2013-04-19

Highlights: •Shear stress increased TCF/LEF activity and stimulated β-catenin nuclear localization. •Rac1, Cdc42, and RhoA displayed distinct dynamic activity patterns under flow. •Rac1 and Cdc42, but not RhoA, regulate shear stress-driven TCF/LEF activation. •Cytoskeleton did not significantly affect shear stress-induced TCF/LEF activation. -- Abstract: Beta-catenin-dependent TCF/LEF (T-cell factor/lymphocyte enhancing factor) is known to be mechanosensitive and an important regulator for promoting bone formation. However, the functional connection between TCF/LEF activity and Rho family GTPases is not well understood in osteoblasts. Herein we investigated the molecular mechanisms underlying oscillatory shear stress-induced TCF/LEF activity in MC3T3-E1 osteoblast cells using live cell imaging.more » We employed fluorescence resonance energy transfer (FRET)-based and green fluorescent protein (GFP)-based biosensors, which allowed us to monitor signal transduction in living cells in real time. Oscillatory (1 Hz) shear stress (10 dynes/cm{sup 2}) increased TCF/LEF activity and stimulated translocation of β-catenin to the nucleus with the distinct activity patterns of Rac1 and Cdc42. The shear stress-induced TCF/LEF activity was blocked by the inhibition of Rac1 and Cdc42 with their dominant negative mutants or selective drugs, but not by a dominant negative mutant of RhoA. In contrast, constitutively active Rac1 and Cdc42 mutants caused a significant enhancement of TCF/LEF activity. Moreover, activation of Rac1 and Cdc42 increased the basal level of TCF/LEF activity, while their inhibition decreased the basal level. Interestingly, disruption of cytoskeletal structures or inhibition of myosin activity did not significantly affect shear stress-induced TCF/LEF activity. Although Rac1 is reported to be involved in β-catenin in cancer cells, the involvement of Cdc42 in β-catenin signaling in osteoblasts has not been identified. Our findings in this study demonstrate that both Rac1 and Cdc42 GTPases are critical regulators in shear stress-driven β-catenin signaling in osteoblasts.« less

The Association between Physical Activity and Eating Self-Regulation in Overweight and Obese Women

PubMed Central

Carraça, Eliana V.; Silva, Marlene N.; Coutinho, Sílvia R.; Vieira, Paulo N.; Minderico, Cláudia S.; Sardinha, Luís B.; Teixeira, Pedro J.

2013-01-01

Objective Successful weight management relies heavily on eating and exercise behaviors. However, little is known about the association between both on a psychosocial level. This study examined the relationship between exercise and eating regulation by exploring the mediating effects of negative body image investment and depressive mood, and their stability through time. Methods Analyses were conducted at two different moments (12 and 36 months), involving a sample of 221 overweight/obese women (age: 37.6 ± 7 years; BMI: 31.6 ± 4.1 kg/m2) that participated in a behavioral weight control intervention. Bivariate correlations and mediation analyses using Preacher & Hayes resampling procedures were conducted. Results At 12 months, negative body image investment was the only significant mediator of the exercise-eating relationship. This variable explained larger portions of the indirect effects of structured rather than lifestyle exercise on eating. At 36 months, negative investment and to a lesser extent depressive mood partially explained the exercise-eating association. Conclusions Our findings suggest that, besides physiological effects of exercise, psychological mechanisms related to body image and mood also explain the role of physical activity as a ‘gateway behavior’ for improved eating regulation in overweight women. These effects appear to be stable and may help understand the key role of exercise in long-term weight management. PMID:24217426

Positive and negative regulation of T cell responses by fibroblastic reticular cells within paracortical regions of lymph nodes

PubMed Central

Siegert, Stefanie; Luther, Sanjiv A.

2012-01-01

Fibroblastic reticular cells (FRC) form the structural backbone of the T cell rich zones in secondary lymphoid organs (SLO), but also actively influence the adaptive immune response. They provide a guidance path for immigrating T lymphocytes and dendritic cells (DC) and are the main local source of the cytokines CCL19, CCL21, and IL-7, all of which are thought to positively regulate T cell homeostasis and T cell interactions with DC. Recently, FRC in lymph nodes (LN) were also described to negatively regulate T cell responses in two distinct ways. During homeostasis they express and present a range of peripheral tissue antigens, thereby participating in peripheral tolerance induction of self-reactive CD8+ T cells. During acute inflammation T cells responding to foreign antigens presented on DC very quickly release pro-inflammatory cytokines such as interferon γ. These cytokines are sensed by FRC which transiently produce nitric oxide (NO) gas dampening the proliferation of neighboring T cells in a non-cognate fashion. In summary, we propose a model in which FRC engage in a bidirectional crosstalk with both DC and T cells to increase the efficiency of the T cell response. However, during an acute response, FRC limit excessive expansion and inflammatory activity of antigen-specific T cells. This negative feedback loop may help to maintain tissue integrity and function during rapid organ growth. PMID:22973278

The Dishevelled-binding protein CXXC5 negatively regulates cutaneous wound healing

PubMed Central

Lee, Soung-Hoon; Kim, Mi-Yeon; Kim, Hyun-Yi; Lee, Young-Mi; Kim, Heesu; Nam, Kyoung Ae; Roh, Mi Ryung; Min, Do Sik; Chung, Kee Yang

2015-01-01

Wnt/β-catenin signaling plays important roles in cutaneous wound healing and dermal fibrosis. However, its regulatory mechanism has not been fully elucidated, and a commercially available wound-healing agent targeting this pathway is desirable but currently unavailable. We found that CXXC-type zinc finger protein 5 (CXXC5) serves as a negative feedback regulator of the Wnt/β-catenin pathway by interacting with the Dishevelled (Dvl) protein. In humans, CXXC5 protein levels were reduced in epidermal keratinocytes and dermal fibroblasts of acute wounds. A differential regulation of β-catenin, α-smooth muscle actin (α-SMA), and collagen I by overexpression and silencing of CXXC5 in vitro indicated a critical role for this factor in myofibroblast differentiation and collagen production. In addition, CXXC5−/− mice exhibited accelerated cutaneous wound healing, as well as enhanced keratin 14 and collagen synthesis. Protein transduction domain (PTD)–Dvl-binding motif (DBM), a competitor peptide blocking CXXC5-Dvl interactions, disrupted this negative feedback loop and activated β-catenin and collagen production in vitro. Co-treatment of skin wounds with PTD-DBM and valproic acid (VPA), a glycogen synthase kinase 3β (GSK3β) inhibitor which activates the Wnt/β-catenin pathway, synergistically accelerated cutaneous wound healing in mice. Together, these data suggest that CXXC5 would represent a potential target for future therapies aimed at improving wound healing. PMID:26056233

With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl- cotransporters.

PubMed

Mercado, Adriana; de Los Heros, Paola; Melo, Zesergio; Chávez-Canales, María; Murillo-de-Ozores, Adrián R; Moreno, Erika; Bazúa-Valenti, Silvana; Vázquez, Norma; Hadchouel, Juliette; Gamba, Gerardo

2016-07-01

The K(+)-Cl(-) cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms. Copyright © 2016 the American Physiological Society.

With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl− cotransporters

PubMed Central

Mercado, Adriana; de los Heros, Paola; Melo, Zesergio; Chávez-Canales, María; Murillo-de-Ozores, Adrián R.; Moreno, Erika; Bazúa-Valenti, Silvana; Vázquez, Norma; Hadchouel, Juliette

2016-01-01

The K+-Cl− cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na+-K+-2Cl− cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms. PMID:27170636

Mechanisms of JAK/STAT pathway negative regulation by the short coreceptor Eye Transformer/Latran.

PubMed

Fisher, Katherine H; Stec, Wojciech; Brown, Stephen; Zeidler, Martin P

2016-02-01

Transmembrane receptors interact with extracellular ligands to transduce intracellular signaling cascades, modulate target gene expression, and regulate processes such as proliferation, apoptosis, differentiation, and homeostasis. As a consequence, aberrant signaling events often underlie human disease. Whereas the vertebrate JAK/STAT signaling cascade is transduced via multiple receptor combinations, the Drosophila pathway has only one full-length signaling receptor, Domeless (Dome), and a single negatively acting receptor, Eye Transformer/Latran (Et/Lat). Here we investigate the molecular mechanisms underlying Et/Lat activity. We demonstrate that Et/Lat negatively regulates the JAK/STAT pathway activity and can bind to Dome, thus reducing Dome:Dome homodimerization by creating signaling-incompetent Dome:Et/Lat heterodimers. Surprisingly, we find that Et/Lat is able to bind to both JAK and STAT92E but, despite the presence of putative cytokine-binding motifs, does not detectably interact with pathway ligands. We find that Et/Lat is trafficked through the endocytic machinery for lysosomal degradation but at a much slower rate than Dome, a difference that may enhance its ability to sequester Dome into signaling-incompetent complexes. Our data offer new insights into the molecular mechanism and regulation of Et/Lat in Drosophila that may inform our understanding of how short receptors function in other organisms. © 2016 Fisher et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Identification of Mur34 as the Novel Negative Regulator Responsible for the Biosynthesis of Muraymycin in Streptomyces sp. NRRL30471

PubMed Central

Xu, Dongmei; Liu, Guang; Cheng, Lin; Lu, Xinhua; Chen, Wenqing; Deng, Zixin

2013-01-01

Background Muraymycin, a potent translocase I (MraY) inhibitor, is produced by Streptomyces sp. NRRL30471. The muraymycin gene cluster (mur) was recently cloned, and bioinformatic analysis of mur34 revealed its encoding product exhibits high homology to a large family of proteins, including KanI and RacI in individual biosynthetic pathway of kanamycin and ribostamycin. However, the precise role of these proteins remains unknown. Principal Findings Here we report the identification of Mur34 as the novel negative regulator involved in muraymycin biosynthesis. Independent disruption of mur34 on chromosome and cosmid directly resulted in significant improvement of muraymycin production by at least 10 folds, thereof confirming the negative function of Mur34 during muraymycin biosynthesis and realizing the engineered production of muraymycin in heterologous host. Gene expression analysis indicated that the transcription level of the mur genes in mur34 mutant (DM-5) was dramatically enhanced by ca. 30 folds. Electrophoretic mobility shift assay (EMSA) showed that Mur34 specifically bound to the promoter region of mur33. Further experiments showed that a 28-bp region downstream of the transcription start point (TSP) was protected by His6Mur34, and the −10 region is essential for the activity of mur33 promoter. Conclusions Mur34 plays an unambiguously negative role in muraymycin biosynthesis via binding to the upstream of mur33. More importantly, Mur34 represents a novel family of regulators acting in negative manner to regulate the secondary metabolites biosynthesis in bacteria. PMID:24143177

Expression of Tlx in both stem cells and transit amplifying progenitors regulates stem cell activation and differentiation in the neonatal lateral subependymal zone.

PubMed

Obernier, Kirsten; Simeonova, Ina; Fila, Tatiana; Mandl, Claudia; Hölzl-Wenig, Gabriele; Monaghan-Nichols, Paula; Ciccolini, Francesca

2011-09-01

Niche homeostasis in the postnatal subependymal zone of the lateral ventricle (lSEZ) requires coordinated proliferation and differentiation of neural progenitor cells. The mechanisms regulating this balance are scarcely known. Recent observations indicate that the orphan nuclear receptor Tlx is an intrinsic factor essential in maintaining this balance. However, the effect of Tlx on gene expression depends on age and cell-type cues. Therefore, it is essential to establish its expression pattern at different developmental ages. Here, we show for the first time that in the neonatal lSEZ activated neural stem cells (NSCs) and especially transit-amplifying progenitors (TAPs) express Tlx and that its expression may be regulated at the posttranscriptional level. We also provide evidence that in both cell types Tlx affects gene expression in a positive and negative manner. In activated NSCs, but not in TAPs, absence of Tlx leads to overexpression of negative cell cycle regulators and impairment of proliferation. Moreover, in both cell types, the homeobox transcription factor Dlx2 is downregulated in the absence of Tlx. This is paralleled by increased expression of Olig2 in activated NSCs and glial fibrillary acidic protein in TAPs, indicating that in both populations Tlx decreases gliogenesis. Consistent with this, we found a higher proportion of cells expressing glial makers in the neonatal lSEZ of mutant mice than in the wild type counterpart. Thus, Tlx playing a dual role affects the expression of distinct genes in these two lSEZ cell types. Copyright © 2011 AlphaMed Press.

Mechanistic insights into the allosteric regulation of bacterial ADP-glucose pyrophosphorylases

PubMed Central

Comino, Natalia; Cifuente, Javier O.; Marina, Alberto; Orrantia, Ane; Eguskiza, Ander; Guerin, Marcelo E.

2017-01-01

ADP-glucose pyrophosphorylase (AGPase) controls bacterial glycogen and plant starch biosynthetic pathways, the most common carbon storage polysaccharides in nature. AGPase activity is allosterically regulated by a series of metabolites in the energetic flux within the cell. Very recently, we reported the first crystal structures of the paradigmatic AGPase from Escherichia coli (EcAGPase) in complex with its preferred physiological negative and positive allosteric regulators, adenosine 5′-monophosphate (AMP) and fructose 1,6-bisphosphate (FBP), respectively. However, understanding the molecular mechanism by which AMP and FBP allosterically modulates EcAGPase enzymatic activity still remains enigmatic. Here we found that single point mutations of key residues in the AMP-binding site decrease its inhibitory effect but also clearly abolish the overall AMP-mediated stabilization effect in wild-type EcAGPase. Single point mutations of key residues for FBP binding did not revert the AMP-mediated stabilization. Strikingly, an EcAGPase-R130A mutant displayed a dramatic increase in activity when compared with wild-type EcAGPase, and this increase correlated with a significant increment of glycogen content in vivo. The crystal structure of EcAGPase-R130A revealed unprecedented conformational changes in structural elements involved in the allosteric signal transmission. Altogether, we propose a model in which the positive and negative energy reporters regulate AGPase catalytic activity via intra- and interprotomer cross-talk, with a “sensory motif” and two loops, RL1 and RL2, flanking the ATP-binding site playing a significant role. The information reported herein provides exciting possibilities for industrial/biotechnological applications. PMID:28223362

Epidermal growth factor induces G protein-coupled receptor 30 expression in estrogen receptor-negative breast cancer cells.

PubMed

Albanito, Lidia; Sisci, Diego; Aquila, Saveria; Brunelli, Elvira; Vivacqua, Adele; Madeo, Antonio; Lappano, Rosamaria; Pandey, Deo Prakash; Picard, Didier; Mauro, Loredana; Andò, Sebastiano; Maggiolini, Marcello

2008-08-01

Different cellular receptors mediate the biological effects induced by estrogens. In addition to the classical nuclear estrogen receptors (ERs)-alpha and -beta, estrogen also signals through the seven-transmembrane G-protein-coupled receptor (GPR)-30. Using as a model system SkBr3 and BT20 breast cancer cells lacking the classical ER, the regulation of GPR30 expression by 17beta-estradiol, the selective GPR30 ligand G-1, IGF-I, and epidermal growth factor (EGF) was evaluated. Transient transfections with an expression plasmid encoding a short 5'-flanking sequence of the GPR30 gene revealed that an activator protein-1 site located within this region is required for the activating potential exhibited only by EGF. Accordingly, EGF up-regulated GPR30 protein levels, which accumulated predominantly in the intracellular compartment. The stimulatory role elicited by EGF on GPR30 expression was triggered through rapid ERK phosphorylation and c-fos induction, which was strongly recruited to the activator protein-1 site found in the short 5'-flanking sequence of the GPR30 gene. Of note, EGF activating the EGF receptor-MAPK transduction pathway stimulated a regulatory loop that subsequently engaged estrogen through GPR30 to boost the proliferation of SkBr3 and BT20 breast tumor cells. The up-regulation of GPR30 by ligand-activated EGF receptor-MAPK signaling provides new insight into the well-known estrogen and EGF cross talk, which, as largely reported, contributes to breast cancer progression. On the basis of our results, the action of EGF may include the up-regulation of GPR30 in facilitating a stimulatory role of estrogen, even in ER-negative breast tumor cells.

Complex transcriptional and post-transcriptional regulation of an enzyme for Lipopolysaccharide modification

PubMed Central

Moon, Kyung; Six, David A.; Lee, Hyun-Jung; Raetz, Christian R.H.; Gottesman, Susan

2013-01-01

Summary The PhoQ/PhoP two-component system activates many genes for lipopolysaccharide (LPS) modification when cells are grown at low Mg2+ concentrations. An additional target of PhoQ and PhoP is MgrR, an Hfq-dependent small RNA that negatively regulates expression of eptB, also encoding a protein that carries out LPS modification. Examination of LPS confirmed that MgrR effectively silences EptB; the phosphoethanolamine modification associated with EptB is found in ΔmgrR::kan but not mgrR+ cells. Sigma E has been reported to positively regulate eptB, although the eptB promoter does not have the expected Sigma E recognition motifs. The effects of Sigma E and deletion of mgrR on levels of eptB mRNA were independent, and the same 5′ end was found in both cases. In vitro transcription and the behavior of transcriptional and translational fusions demonstrate that Sigma E acts directly at the level of transcription initiation for eptB, from the same start point as Sigma 70. The results suggest that when Sigma E is active, synthesis of eptB transcript outstrips MgrR-dependent degradation; presumably the modification of LPS is important under these conditions. Adding to the complexity of eptB regulation is a second sRNA, ArcZ, which also directly and negatively regulates eptB. PMID:23659637

Calcium/calmodulin-dependent protein kinase II activity regulates the proliferative potential of growth plate chondrocytes.

PubMed

Li, Yuwei; Ahrens, Molly J; Wu, Amy; Liu, Jennifer; Dudley, Andrew T

2011-01-01

For tissues that develop throughout embryogenesis and into postnatal life, the generation of differentiated cells to promote tissue growth is at odds with the requirement to maintain the stem cell/progenitor cell population to preserve future growth potential. In the growth plate cartilage, this balance is achieved in part by establishing a proliferative phase that amplifies the number of progenitor cells prior to terminal differentiation into hypertrophic chondrocytes. Here, we show that endogenous calcium/calmodulin-dependent protein kinase II (CamkII, also known as Camk2) activity is upregulated prior to hypertrophy and that loss of CamkII function substantially blocks the transition from proliferation to hypertrophy. Wnt signaling and Pthrp-induced phosphatase activity negatively regulate CamkII activity. Release of this repression results in activation of multiple effector pathways, including Runx2- and β-catenin-dependent pathways. We present an integrated model for the regulation of proliferation potential by CamkII activity that has important implications for studies of growth control and adult progenitor/stem cell populations.

Dok1 and Dok2 proteins regulate natural killer cell development and function

PubMed Central

Celis-Gutierrez, Javier; Boyron, Marilyn; Walzer, Thierry; Pandolfi, Pier Paolo; Jonjić, Stipan; Olive, Daniel; Dalod, Marc; Vivier, Eric; Nunès, Jacques A

2014-01-01

Natural killer (NK) cells are involved in immune responses against tumors and microbes. NK-cell activation is regulated by intrinsic and extrinsic mechanisms that ensure NK tolerance and efficacy. Here, we show that the cytoplasmic signaling molecules Dok1 and Dok2 are tyrosine phosphorylated upon NK-cell activation. Overexpression of Dok proteins in human NK cells reduces cell activation induced by NK-cell-activating receptors. Dok1 and Dok2 gene ablation in mice induces an NK-cell maturation defect and leads to increased IFN-γ production induced by activating receptors. Taken together, these results reveal that Dok1 and Dok2 proteins are involved in an intrinsic negative feedback loop downstream of NK-cell-activating receptors in mouse and human. PMID:24963146

Drive for thinness, affect regulation and physical activity in eating disorders: a daily life study.

PubMed

Vansteelandt, Kristof; Rijmen, Frank; Pieters, Guido; Probst, Michel; Vanderlinden, Johan

2007-08-01

Using Ecological Momentary Assessment, the within patient associations between drive for thinness, emotional states, momentary urge to be physically active and physical activity were studied in 32 inpatients with an eating disorder. Participants received an electronic device and had to indicate at nine random times a day during 1 week their momentary drive for thinness, positive and negative emotional states and their urge to be physically active and physical activity. Multilevel analyses indicated that patients with higher mean levels for urge to be physically active were characterized by lower body mass index (BMI) and chronically negative affect whereas patients with higher mean levels for physical activity were characterized by lower BMI and higher dispositions for drive for thinness. In addition, within patient relations between drive for thinness and urge to be physically active were moderated by BMI and chronically negative affect whereas within patient relations between drive for thinness and physical activity were moderated by BMI. Finally, also positive emotional states were significantly associated with physical activity within patients. By using a daily process design, characteristics of physical activity were revealed that have not been identified with assessment methods that have a lower time resolution.

SIRT1 Activity Is Linked to Its Brain Region-Specific Phosphorylation and Is Impaired in Huntington’s Disease Mice

PubMed Central

Tulino, Raffaella; Benjamin, Agnesska C.; Jolinon, Nelly; Smith, Donna L.; Chini, Eduardo N.; Carnemolla, Alisia; Bates, Gillian P.

2016-01-01

Huntington’s disease (HD) is a neurodegenerative disorder for which there are no disease-modifying treatments. SIRT1 is a NAD+-dependent protein deacetylase that is implicated in maintaining neuronal health during development, differentiation and ageing. Previous studies suggested that the modulation of SIRT1 activity is neuroprotective in HD mouse models, however, the mechanisms controlling SIRT1 activity are unknown. We have identified a striatum-specific phosphorylation-dependent regulatory mechanism of SIRT1 induction under normal physiological conditions, which is impaired in HD. We demonstrate that SIRT1 activity is down-regulated in the brains of two complementary HD mouse models, which correlated with altered SIRT1 phosphorylation levels. This SIRT1 impairment could not be rescued by the ablation of DBC1, a negative regulator of SIRT1, but was linked to changes in the sub-cellular distribution of AMPK-α1, a positive regulator of SIRT1 function. This work provides insights into the regulation of SIRT1 activity with the potential for the development of novel therapeutic strategies. PMID:26815359

Myostatin and the skeletal muscle atrophy and hypertrophy signaling pathways.

PubMed

Rodriguez, J; Vernus, B; Chelh, I; Cassar-Malek, I; Gabillard, J C; Hadj Sassi, A; Seiliez, I; Picard, B; Bonnieu, A

2014-11-01

Myostatin, a member of the transforming growth factor-β superfamily, is a potent negative regulator of skeletal muscle growth and is conserved in many species, from rodents to humans. Myostatin inactivation can induce skeletal muscle hypertrophy, while its overexpression or systemic administration causes muscle atrophy. As it represents a potential target for stimulating muscle growth and/or preventing muscle wasting, myostatin regulation and functions in the control of muscle mass have been extensively studied. A wealth of data strongly suggests that alterations in skeletal muscle mass are associated with dysregulation in myostatin expression. Moreover, myostatin plays a central role in integrating/mediating anabolic and catabolic responses. Myostatin negatively regulates the activity of the Akt pathway, which promotes protein synthesis, and increases the activity of the ubiquitin-proteasome system to induce atrophy. Several new studies have brought new information on how myostatin may affect both ribosomal biogenesis and translation efficiency of specific mRNA subclasses. In addition, although myostatin has been identified as a modulator of the major catabolic pathways, including the ubiquitin-proteasome and the autophagy-lysosome systems, the underlying mechanisms are only partially understood. The goal of this review is to highlight outstanding questions about myostatin-mediated regulation of the anabolic and catabolic signaling pathways in skeletal muscle. Particular emphasis has been placed on (1) the cross-regulation between myostatin, the growth-promoting pathways and the proteolytic systems; (2) how myostatin inhibition leads to muscle hypertrophy; and (3) the regulation of translation by myostatin.

Human T-Cell Leukemia Virus Type 1 (HTLV-1) Tax Requires CADM1/TSLC1 for Inactivation of the NF-κB Inhibitor A20 and Constitutive NF-κB Signaling

PubMed Central

Thomas, Remy; van der Weyden, Louise; Rauch, Dan; Ratner, Lee; Nyborg, Jennifer K.; Ramos, Juan Carlos; Takai, Yoshimi; Shembade, Noula

2015-01-01

Persistent activation of NF-κB by the Human T-cell leukemia virus type 1 (HTLV-1) oncoprotein, Tax, is vital for the development and pathogenesis of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). K63-linked polyubiquitinated Tax activates the IKK complex in the plasma membrane-associated lipid raft microdomain. Tax also interacts with TAX1BP1 to inactivate the NF-κB negative regulatory ubiquitin-editing A20 enzyme complex. However, the molecular mechanisms of Tax-mediated IKK activation and A20 protein complex inactivation are poorly understood. Here, we demonstrated that membrane associated CADM1 (Cell adhesion molecule1) recruits Ubc13 to Tax, causing K63-linked polyubiquitination of Tax, and IKK complex activation in the membrane lipid raft. The c-terminal cytoplasmic tail containing PDZ binding motif of CADM1 is critical for Tax to maintain persistent NF-κB activation. Finally, Tax failed to inactivate the NF-κB negative regulator ubiquitin-editing enzyme A20 complex, and activate the IKK complex in the lipid raft in absence of CADM1. Our results thus indicate that CADM1 functions as a critical scaffold molecule for Tax and Ubc13 to form a cellular complex with NEMO, TAX1BP1 and NRP, to activate the IKK complex in the plasma membrane-associated lipid rafts, to inactivate NF-κB negative regulators, and maintain persistent NF-κB activation in HTLV-1 infected cells. PMID:25774694

The histone methyltransferase Smyd2 is a negative regulator of macrophage activation by suppressing interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) production.

PubMed

Xu, Guiliang; Liu, Guilin; Xiong, Sidong; Liu, Haiyan; Chen, Xi; Zheng, Biao

2015-02-27

SET and MYND domain-containing 2 (Smyd2), a histone 3 lysine 4- and histone 3 lysine 36 (H3K36)-specific methyltransferase, plays critical roles in cardiac development and tumorigenesis. However, the role of Smyd2 in immunity and inflammation remains poorly understood. In this study, we report that Smyd2 is a novel negative regulator for macrophage activation and M1 polarization. Elevated Smyd2 expression suppresses the production of proinflammatory cytokines, including IL-6 and TNF, and inhibits the expression of important cell surface molecules, including major MHC-II and costimulatory molecules. Furthermore, macrophages with high Smyd2 expression inhibit Th-17 cell differentiation but promote regulatory T cell differentiation as a result of increased TGF-β production and decreased IL-6 secretion. In macrophages, Smyd2 specifically facilitates H3K36 dimethylation at Tnf and Il6 promoters to suppress their transcription and inhibits NF-κB and ERK signaling. Therefore, our data demonstrate that epigenetic modification by Smyd2-mediated H3K36 dimethylation at Tnf and Il6 promoters plays an important role in the regulation of macrophage activation during inflammation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Roles of Stat3 and ERK in G-CSF signaling.

PubMed

Kamezaki, Kenjirou; Shimoda, Kazuya; Numata, Akihiko; Haro, Takashi; Kakumitsu, Haruko; Yoshie, Masumi; Yamamoto, Masahiro; Takeda, Kiyoshi; Matsuda, Tadashi; Akira, Shizuo; Ogawa, Katsuhiro; Harada, Mine

2005-02-01

G-CSF specifically stimulates the proliferation and differentiation of cells that are committed to the neutrophil-granulocyte lineage. Although Stat3 was thought to be essential for the transduction of G-CSF-induced cell proliferation and differentiation signals, mice deficient for Stat3 in hematopoietic cells show neutrocytosis and infiltration of cells into the digestive tract. The number of progenitor cells in the neutrophil lineage is not changed, and G-CSF-induced proliferation of progenitor cells and prolonged neutrophil survival were observed in Stat3-deficient mice. In hematopoietic cells from Stat3-deficient mice, trace levels of SOCS3, a negative regulator of granulopoiesis, were observed, and SOCS3 expression was not induced by G-CSF stimulation. Stat3-null bone marrow cells displayed a significant activation of extra-cellular regulated kinase 1 (ERK1)/ERK2 under basal conditions, and the activation of ERK was enhanced and sustained by G-CSF stimulation. Furthermore, the augmented proliferation of Stat3-deficient bone marrow cells in response to G-CSF was dramatically decreased by addition of a MEK1 inhibitor. These results indicate that Stat3 functions as a negative regulator of G-CSF signaling by inducing SOCS3 expression and that ERK activation is the major factor responsible for inducing the proliferation of hematopoietic cells in response to G-CSF.

CDK5 Regulatory Subunit-Associated Protein 1-like 1 Negatively Regulates Adipocyte Differentiation through Activation of Wnt Signaling Pathway.

PubMed

Take, Kazumi; Waki, Hironori; Sun, Wei; Wada, Takahito; Yu, Jing; Nakamura, Masahiro; Aoyama, Tomohisa; Yamauchi, Toshimasa; Kadowaki, Takashi

2017-08-04

CDK5 Regulatory Subunit-Associated Protein 1-like 1 (CDKAL1) was identified as a susceptibility gene for type 2 diabetes and body mass index in genome-wide association studies. Although it was reported that CDKAL1 is a methylthiotransferase essential for tRNA Lys (UUU) and faithful translation of proinsulin generated in pancreatic β cells, the role of CDKAL1 in adipocytes has not been understood well. In this study, we found that CDKAL1 is expressed in adipose tissue and its expression is increased during differentiation. Stable overexpression of CDKAL1, however, inhibited adipocyte differentiation of 3T3-L1 cells, whereas knockdown of CDKAL1 promoted differentiation. CDKAL1 increased protein levels of β-catenin and its active unphosphorylated form in the nucleus, thereby promoting Wnt target gene expression, suggesting that CDKAL1 activated the Wnt/β-catenin pathway-a well-characterized inhibitory regulator of adipocyte differentiation. Mutant experiments show that conserved cysteine residues of Fe-S clusters of CDKAL1 are essential for its anti-adipogenic action. Our results identify CDKAL1 as novel negative regulator of adipocyte differentiation and provide insights into the link between CDKAL1 and metabolic diseases such as type 2 diabetes and obesity.

Affective regulation of stereotype activation: It’s the (accessible) thought that counts

PubMed Central

Huntsinger, Jeffrey R.; Sinclair, Stacey; Dunn, Elizabeth; Clore, Gerald L.

2010-01-01

Extant research demonstrates that positive affect, compared to negative affect, increases stereotyping. In four experiments we explore whether the link between affect and stereotyping depends, critically, on the relative accessibility of stereotype-relevant thoughts and response tendencies. As well as manipulating mood, we measured or manipulated the accessibility of egalitarian response tendencies (Experiments 1-2) and counter-stereotypic thoughts (Experiments 3-4). In the absence of such response tendencies and thoughts, people in positive moods displayed greater stereotype activation —consistent with past research. By contrast, in the presence of accessible egalitarian response tendencies or counter-stereotypic thoughts, people in positive moods exhibited less stereotype activation than those in negative moods. PMID:20363909

Reward, addiction, and emotion regulation systems associated with rejection in love.

PubMed

Fisher, Helen E; Brown, Lucy L; Aron, Arthur; Strong, Greg; Mashek, Debra

2010-07-01

Romantic rejection causes a profound sense of loss and negative affect. It can induce clinical depression and in extreme cases lead to suicide and/or homicide. To begin to identify the neural systems associated with this natural loss state, we used functional magnetic resonance imaging to study 10 women and 5 men who had recently been rejected by a partner but reported they were still intensely "in love." Participants alternately viewed a photograph of their rejecting beloved and a photograph of a familiar, individual, interspersed with a distraction-attention task. Their responses while looking at their rejecter included love, despair, good, and bad memories, and wondering why this happened. Activation specific to the image of the beloved occurred in areas associated with gains and losses, craving and emotion regulation and included the ventral tegmental area (VTA) bilaterally, ventral striatum, medial and lateral orbitofrontal/prefrontal cortex, and cingulate gyrus. Compared with data from happily-in-love individuals, the regional VTA activation suggests that mesolimbic reward/survival systems are involved in romantic passion regardless of whether one is happily or unhappily in love. Forebrain activations associated with motivational relevance, gain/loss, cocaine craving, addiction, and emotion regulation suggest that higher-order systems subject to experience and learning also may mediate the rejection reaction. The results show activation of reward systems, previously identified by monetary stimuli, in a natural, endogenous, negative emotion state. Activation of areas involved in cocaine addiction may help explain the obsessive behaviors associated with rejection in love.

A HLA class I cis-regulatory element whose activity can be modulated by hormones.

PubMed

Sim, B C; Hui, K M

1994-12-01

To elucidate the basis of the down-regulation in major histocompatibility complex (MHC) class I gene expression and to identify possible DNA-binding regulatory elements that have the potential to interact with class I MHC genes, we have studied the transcriptional regulation of class I HLA genes in human breast carcinoma cells. A 9 base pair (bp) negative cis-regulatory element (NRE) has been identified using band-shift assays employing DNA sequences derived from the 5'-flanking region of HLA class I genes. This 9-bp element, GTCATGGCG, located within exon I of the HLA class I gene, can potently inhibit the expression of a heterologous thymidine kinase (TK) gene promoter and the HLA enhancer element. Furthermore, this regulatory element can exert its suppressive function in either the sense or anti-sense orientation. More interestingly, NRE can suppress dexamethasone-mediated gene activation in the context of the reported glucocorticoid-responsive element (GRE) in MCF-7 cells but has no influence on the estrogen-mediated transcriptional activation of MCF-7 cells in the context of the reported estrogen-responsive element (ERE). Furthermore, the presence of such a regulatory element within the HLA class I gene whose activity can be modulated by hormones correlates well with our observation that the level of HLA class I gene expression can be down-regulated by hormones in human breast carcinoma cells. Such interactions between negative regulatory elements and specific hormone trans-activators are novel and suggest a versatile form of transcriptional control.

Nitric oxide negatively regulates mammalian adult neurogenesis

NASA Astrophysics Data System (ADS)

Packer, Michael A.; Stasiv, Yuri; Benraiss, Abdellatif; Chmielnicki, Eva; Grinberg, Alexander; Westphal, Heiner; Goldman, Steven A.; Enikolopov, Grigori

2003-08-01

Neural progenitor cells are widespread throughout the adult central nervous system but only give rise to neurons in specific loci. Negative regulators of neurogenesis have therefore been postulated, but none have yet been identified as subserving a significant role in the adult brain. Here we report that nitric oxide (NO) acts as an important negative regulator of cell proliferation in the adult mammalian brain. We used two independent approaches to examine the function of NO in adult neurogenesis. In a pharmacological approach, we suppressed NO production in the rat brain by intraventricular infusion of an NO synthase inhibitor. In a genetic approach, we generated a null mutant neuronal NO synthase knockout mouse line by targeting the exon encoding active center of the enzyme. In both models, the number of new cells generated in neurogenic areas of the adult brain, the olfactory subependyma and the dentate gyrus, was strongly augmented, which indicates that division of neural stem cells in the adult brain is controlled by NO and suggests a strategy for enhancing neurogenesis in the adult central nervous system.

PIF4 and PIF5 Transcription Factors Link Blue Light and Auxin to Regulate the Phototropic Response in Arabidopsis[C][W][OPEN

PubMed Central

Sun, Jiaqiang; Qi, Linlin; Li, Yanan; Zhai, Qingzhe; Li, Chuanyou

2013-01-01

Both blue light (BL) and auxin are essential for phototropism in Arabidopsis thaliana. However, the mechanisms by which light is molecularly linked to auxin during phototropism remain elusive. Here, we report that PHYTOCHROME INTERACTING FACTOR4 (PIF4) and PIF5 act downstream of the BL sensor PHOTOTROPIN1 (PHOT1) to negatively modulate phototropism in Arabidopsis. We also reveal that PIF4 and PIF5 negatively regulate auxin signaling. Furthermore, we demonstrate that PIF4 directly activates the expression of the AUXIN/INDOLE-3-ACETIC ACID (IAA) genes IAA19 and IAA29 by binding to the G-box (CACGTG) motifs in their promoters. Our genetic assays demonstrate that IAA19 and IAA29, which physically interact with AUXIN RESPONSE FACTOR7 (ARF7), are sufficient for PIF4 to negatively regulate auxin signaling and phototropism. This study identifies a key step of phototropic signaling in Arabidopsis by showing that PIF4 and PIF5 link light and auxin. PMID:23757399

miR-200a inhibits migration of triple-negative breast cancer cells through direct repression of the EPHA2 oncogene.

PubMed

Tsouko, Efrosini; Wang, Jun; Frigo, Daniel E; Aydoğdu, Eylem; Williams, Cecilia

2015-09-01

Triple-negative breast cancer (TNBC) is characterized by aggressiveness and affects 10-20% of breast cancer patients. Since TNBC lacks expression of ERα, PR and HER2, existing targeted treatments are not effective and the survival is poor. In this study, we demonstrate that the tumor suppressor microRNA miR-200a directly regulates the oncogene EPH receptor A2 (EPHA2) and modulates TNBC migration. We show that EPHA2 expression is correlated with poor survival specifically in basal-like breast cancer and that its expression is repressed by miR-200a through direct interaction with the 3'UTR of EPHA2. This regulation subsequently affects the downstream activation of AMP-activated protein kinase (AMPK) and results in decreased cell migration of TNBC. We establish that miR-200a directs cell migration in a dual manner; in addition to regulating the well-characterized E-cadherin pathway it also regulates a EPHA2 pathway. The miR-200a-EPHA2 axis is a novel mechanism highlighting the possibility of utilizing miR-200a delivery to target TNBC metastases. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Tachykinin-1 in the central nervous system regulates adiposity in rodents.

PubMed

Trivedi, Chitrang; Shan, Xiaoye; Tung, Yi-Chun Loraine; Kabra, Dhiraj; Holland, Jenna; Amburgy, Sarah; Heppner, Kristy; Kirchner, Henriette; Yeo, Giles S H; Perez-Tilve, Diego

2015-05-01

Ghrelin is a circulating hormone that targets the central nervous system to regulate feeding and adiposity. The best-characterized neural system that mediates the effects of ghrelin on energy balance involves the activation of neuropeptide Y/agouti-related peptide neurons, expressed exclusively in the arcuate nucleus of the hypothalamus. However, ghrelin receptors are expressed in other neuronal populations involved in the control of energy balance. We combined laser capture microdissection of several nuclei of the central nervous system expressing the ghrelin receptor (GH secretagoge receptor) with microarray gene expression analysis to identify additional neuronal systems involved in the control of central nervous system-ghrelin action. We identified tachykinin-1 (Tac1) as a gene negatively regulated by ghrelin in the hypothalamus. Furthermore, we identified neuropeptide k as the TAC1-derived peptide with more prominent activity, inducing negative energy balance when delivered directly into the brain. Conversely, loss of Tac1 expression enhances the effectiveness of ghrelin promoting fat mass gain both in male and in female mice and increases the susceptibility to diet-induced obesity in ovariectomized mice. Taken together, our data demonstrate a role TAC1 in the control energy balance by regulating the levels of adiposity in response to ghrelin administration and to changes in the status of the gonadal function.

Gibberellin–Abscisic Acid Balances during Arbuscular Mycorrhiza Formation in Tomato

PubMed Central

Martín-Rodríguez, José A.; Huertas, Raúl; Ho-Plágaro, Tania; Ocampo, Juan A.; Turečková, Veronika; Tarkowská, Danuše; Ludwig-Müller, Jutta; García-Garrido, José M.

2016-01-01

Plant hormones have become appropriate candidates for driving functional plant mycorrhization programs, including the processes that regulate the formation of arbuscules in arbuscular mycorrhizal (AM) symbiosis. Here, we examine the role played by ABA/GA interactions regulating the formation of AM in tomato. We report differences in ABA and GA metabolism between control and mycorrhizal roots. Active synthesis and catabolism of ABA occur in AM roots. GAs level increases as a consequence of a symbiosis-induced mechanism that requires functional arbuscules which in turn is dependent on a functional ABA pathway. A negative interaction in their metabolism has been demonstrated. ABA attenuates GA-biosynthetic and increases GA-catabolic gene expression leading to a reduction in bioactive GAs. Vice versa, GA activated ABA catabolism mainly in mycorrhizal roots. The negative impact of GA3 on arbuscule abundance in wild-type plants is partially offset by treatment with ABA and the application of a GA biosynthesis inhibitor rescued the arbuscule abundance in the ABA-deficient sitiens mutant. These findings, coupled with the evidence that ABA application leads to reduce bioactive GA1, support the hypothesis that ABA could act modifying bioactive GA level to regulate AM. Taken together, our results suggest that these hormones perform essential functions and antagonize each other by oppositely regulating AM formation in tomato roots. PMID:27602046

Cyclin-dependent kinase inhibitor p21(Waf1): contemporary view on its role in senescence and oncogenesis.

PubMed

Romanov, V S; Pospelov, V A; Pospelova, T V

2012-06-01

p21(Waf1) was identified as a protein suppressing cyclin E/A-CDK2 activity and was originally considered as a negative regulator of the cell cycle and a tumor suppressor. It is now considered that p21(Waf1) has alternative functions, and the view of its role in cellular processes has begun to change. At present, p21(Waf1) is known to be involved in regulation of fundamental cellular programs: cell proliferation, differentiation, migration, senescence, and apoptosis. In fact, it not only exhibits antioncogenic, but also oncogenic properties. This review provides a contemporary understanding of the functions of p21(Waf1) depending on its intracellular localization. On one hand, when in the nucleus, it serves as a negative cell cycle regulator and tumor suppressor, in particular by participating in the launch of a senescence program. On the other hand, when p21(Waf1) is localized in the cytoplasm, it acts as an oncogene by regulating migration, apoptosis, and proliferation.

KPNB1 mediates PER/CRY nuclear translocation and circadian clock function.

PubMed

Lee, Yool; Jang, A Reum; Francey, Lauren J; Sehgal, Amita; Hogenesch, John B

2015-08-29

Regulated nuclear translocation of the PER/CRY repressor complex is critical for negative feedback regulation of the circadian clock of mammals. However, the precise molecular mechanism is not fully understood. Here, we report that KPNB1, an importin β component of the ncRNA repressor of nuclear factor of activated T cells (NRON) ribonucleoprotein complex, mediates nuclear translocation and repressor function of the PER/CRY complex. RNAi depletion of KPNB1 traps the PER/CRY complex in the cytoplasm by blocking nuclear entry of PER proteins in human cells. KPNB1 interacts mainly with PER proteins and directs PER/CRY nuclear transport in a circadian fashion. Interestingly, KPNB1 regulates the PER/CRY nuclear entry and repressor function, independently of importin α, its classical partner. Moreover, inducible inhibition of the conserved Drosophila importin β in lateral neurons abolishes behavioral rhythms in flies. Collectively, these data show that KPNB1 is required for timely nuclear import of PER/CRY in the negative feedback regulation of the circadian clock.

Pathways from marital aggression to infant emotion regulation: the development of withdrawal in infancy.

PubMed

Crockenberg, Susan C; Leerkes, Esther M; Lekka, Shamila K

2007-02-01

Associations between marital conflict and infant emotion regulation exist, but explanatory pathways have not been explored. For older children, parental behavior partially mediates this association through a "spillover" process. We test: associations between mothers' and fathers' verbally aggressive marital conflict, infant temperament, and infant withdrawal; mediating effects of negative maternal behavior, and moderating effects of infant temperament, exposure to marital arguments, and contact with father. Eighty mothers, 73 fathers, and their 6-month-old infants participated; parents reported marital aggression prenatally, mothers reported infant exposure to arguments, direct caregiving by father, and infant temperament at 5 months. Negative maternal behavior, infant withdrawal, distress to novelty, activity, and look away were observed at 6 months. Mothers' and fathers' aggressive marital conflict predicted infant withdrawal, interactively with exposure to marital arguments and extent of father caregiving, as did infant temperament and negative maternal behavior. Maternal behavior did not mediate between marital conflict and withdrawal.

Identification of a novel human kinase supporter of Ras (hKSR-2) that functions as a negative regulator of Cot (Tpl2) signaling.

PubMed

Channavajhala, Padma L; Wu, Leeying; Cuozzo, John W; Hall, J Perry; Liu, Wei; Lin, Lih-Ling; Zhang, Yuhua

2003-11-21

Kinase suppressor of Ras (KSR) is an integral and conserved component of the Ras signaling pathway. Although KSR is a positive regulator of the Ras/mitogen-activated protein (MAP) kinase pathway, the role of KSR in Cot-mediated MAPK activation has not been identified. The serine/threonine kinase Cot (also known as Tpl2) is a member of the MAP kinase kinase kinase (MAP3K) family that is known to regulate oncogenic and inflammatory pathways; however, the mechanism(s) of its regulation are not precisely known. In this report, we identify an 830-amino acid novel human KSR, designated hKSR-2, using predictions from genomic data base mining based on the structural profile of the KSR kinase domain. We show that, similar to the known human KSR, hKSR-2 co-immunoprecipitates with many signaling components of the Ras/MAPK pathway, including Ras, Raf, MEK-1, and ERK-1/2. In addition, we demonstrate that hKSR-2 co-immunoprecipitates with Cot and that co-expression of hKSR-2 with Cot significantly reduces Cot-mediated MAPK and NF-kappaB activation. This inhibition is specific to Cot, because Ras-induced ERK and IkappaB kinase-induced NF-kappaB activation are not significantly affected by hKSR-2 co-expression. Moreover, Cot-induced interleukin-8 production in HeLa cells is almost completely inhibited by the concurrent expression of hKSR-2, whereas transforming growth factor beta-activated kinase 1 (TAK1)/TAK1-binding protein 1 (TAB1)-induced interleukin-8 production is not affected by hKSR-2 co-expression. Taken together, these results indicate that hKSR-2, a new member of the KSR family, negatively regulates Cot-mediated MAP kinase and NF-kappaB pathway signaling.

Erbin loss promotes cancer cell proliferation through feedback activation of Akt-Skp2-p27 signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Hao; Laboratory of Cellular and Molecular Immunology, Medical School of Henan University, Kaifeng 475004; Song, Yuhua

2015-07-31

Erbin localizes at the basolateral membrane to regulate cell junctions and polarity in epithelial cells. Dysregulation of Erbin has been implicated in tumorigenesis, and yet it is still unclear if and how disrupted Erbin regulates the biological behavior of cancer cells. We report here that depletion of Erbin leads to cancer cell excessive proliferation in vitro and in vivo. Erbin deficiency accelerates S-phase entry by down-regulating CDK inhibitors p21 and p27 via two independent mechanisms. Mechanistically, Erbin loss promotes p27 degradation by enhancing E3 ligase Skp2 activity though augmenting Akt signaling. Interestingly, we also show that Erbin is an unstable protein whenmore » the Akt-Skp2 signaling is aberrantly activated, which can be specifically destructed by SCF-Skp2 ligase. Erbin loss facilitates cell proliferation and migration in Skp2-dependent manner. Thus, our finding illustrates a novel negative feedback loop between Erbin and Akt-Skp2 signaling. It suggests disrupted Erbin links polarity loss, hyperproliferation and tumorigenesis. - Highlights: • Erbin loss leads to cancer cell excessive proliferation in vitro and in vivo. • Erbin loss accelerates cell cycle though down-regulating p21 and p27 expression. • Erbin is a novel negative modulator of Akt1-Skp2-p27 signaling pathway. • Our study suggests that Erbin loss contributes to Skp2 oncogenic function.« less

R-spondin 3 regulates dorsoventral and anteroposterior patterning by antagonizing Wnt/β-catenin signaling in zebrafish embryos.

PubMed

Rong, Xiaozhi; Chen, Chen; Zhou, Pin; Zhou, Yumei; Li, Yun; Lu, Ling; Liu, Yunzhang; Zhou, Jianfeng; Duan, Cunming

2014-01-01

The Wnt/β-catenin or canonical Wnt signaling pathway plays fundamental roles in early development and in maintaining adult tissue homeostasis. R-spondin 3 (Rspo3) is a secreted protein that has been implicated in activating the Wnt/β-catenin signaling in amphibians and mammals. Here we report that zebrafish Rspo3 plays a negative role in regulating the zygotic Wnt/β-catenin signaling. Zebrafish Rspo3 has a unique domain structure. It contains a third furin-like (FU3) domain. This FU3 is present in other four ray-finned fish species studied but not in elephant shark. In zebrafish, rspo3 mRNA is maternally deposited and has a ubiquitous expression in early embryonic stages. After 12 hpf, its expression becomes tissue-specific. Forced expression of rspo3 promotes dorsoanterior patterning and increases the expression of dorsal and anterior marker genes. Knockdown of rspo3 increases ventral-posterior development and stimulates ventral and posterior marker genes expression. Forced expression of rspo3 abolishes exogenous Wnt3a action and reduces the endogenous Wnt signaling activity. Knockdown of rspo3 results in increased Wnt/β-catenin signaling activity. Further analyses indicate that Rspo3 does not promote maternal Wnt signaling. Human RSPO3 has similar action when tested in zebrafish embryos. These results suggest that Rspo3 regulates dorsoventral and anteroposterior patterning by negatively regulating the zygotic Wnt/β-catenin signaling in zebrafish embryos.

R-Spondin 3 Regulates Dorsoventral and Anteroposterior Patterning by Antagonizing Wnt/β-Catenin Signaling in Zebrafish Embryos

PubMed Central

Zhou, Pin; Zhou, Yumei; Li, Yun; Lu, Ling; Liu, Yunzhang; Zhou, Jianfeng; Duan, Cunming

2014-01-01

The Wnt/β-catenin or canonical Wnt signaling pathway plays fundamental roles in early development and in maintaining adult tissue homeostasis. R-spondin 3 (Rspo3) is a secreted protein that has been implicated in activating the Wnt/β-catenin signaling in amphibians and mammals. Here we report that zebrafish Rspo3 plays a negative role in regulating the zygotic Wnt/β-catenin signaling. Zebrafish Rspo3 has a unique domain structure. It contains a third furin-like (FU3) domain. This FU3 is present in other four ray-finned fish species studied but not in elephant shark. In zebrafish, rspo3 mRNA is maternally deposited and has a ubiquitous expression in early embryonic stages. After 12 hpf, its expression becomes tissue-specific. Forced expression of rspo3 promotes dorsoanterior patterning and increases the expression of dorsal and anterior marker genes. Knockdown of rspo3 increases ventral-posterior development and stimulates ventral and posterior marker genes expression. Forced expression of rspo3 abolishes exogenous Wnt3a action and reduces the endogenous Wnt signaling activity. Knockdown of rspo3 results in increased Wnt/β-catenin signaling activity. Further analyses indicate that Rspo3 does not promote maternal Wnt signaling. Human RSPO3 has similar action when tested in zebrafish embryos. These results suggest that Rspo3 regulates dorsoventral and anteroposterior patterning by negatively regulating the zygotic Wnt/β-catenin signaling in zebrafish embryos. PMID:24918770

The metabolic waste ammonium regulates mTORC2 and mTORC1 signaling

PubMed Central

Merhi, Ahmad; Delrée, Paul; Marini, Anna Maria

2017-01-01

Two structurally and functionally distinct mammalian TOR complexes control cell growth and metabolism in physiological and pathological contexts including cancer. Upregulated glutaminolysis is part of the metabolic reprogramming occurring in cancer, providing fuels for growth but also liberating ammonium, a potent neurotoxic waste product. Here, we identify ammonium as a novel dose-dependent signal mediating rapid mTORC2 activation and further regulating mTORC1. We show that ammonium induces rapid RICTOR-dependent phosphorylation of AKT-S473, a process requiring the PI3K pathway and further involving the Src-family kinase YES1, the FAK kinase and the ITGβ1 integrin. Release of calcium from the endoplasmic reticulum store triggers rapid mTORC2 activation, similar to ammonium-induced activation, the latter being conversely prevented by calcium chelation.Moreover, in analogy to growth factors, ammonium triggers the AKT-dependent phosphoinhibition of the TSC complex and of PRAS40, two negative regulators of mTORC1. Consistent with mTORC1 stimulation, ammonium induces the inhibitory phosphorylation of 4EBP1, a negative regulator of protein biogenesis. Ammonium however dually impacts on the phosphorylation of p70S6K1 triggering a transient AKT-independent decrease in the phosphorylation of this second mTORC1 readout. Finally, we reveal ammonium as a dose-dependent stimulator of proliferation. This study underscores an mTORC2 and mTORC1 response to the so-called ammonium waste. PMID:28303961

The metabolic waste ammonium regulates mTORC2 and mTORC1 signaling.

PubMed

Merhi, Ahmad; Delrée, Paul; Marini, Anna Maria

2017-03-17

Two structurally and functionally distinct mammalian TOR complexes control cell growth and metabolism in physiological and pathological contexts including cancer. Upregulated glutaminolysis is part of the metabolic reprogramming occurring in cancer, providing fuels for growth but also liberating ammonium, a potent neurotoxic waste product. Here, we identify ammonium as a novel dose-dependent signal mediating rapid mTORC2 activation and further regulating mTORC1. We show that ammonium induces rapid RICTOR-dependent phosphorylation of AKT-S473, a process requiring the PI3K pathway and further involving the Src-family kinase YES1, the FAK kinase and the ITGβ1 integrin. Release of calcium from the endoplasmic reticulum store triggers rapid mTORC2 activation, similar to ammonium-induced activation, the latter being conversely prevented by calcium chelation.Moreover, in analogy to growth factors, ammonium triggers the AKT-dependent phosphoinhibition of the TSC complex and of PRAS40, two negative regulators of mTORC1. Consistent with mTORC1 stimulation, ammonium induces the inhibitory phosphorylation of 4EBP1, a negative regulator of protein biogenesis. Ammonium however dually impacts on the phosphorylation of p70S6K1 triggering a transient AKT-independent decrease in the phosphorylation of this second mTORC1 readout. Finally, we reveal ammonium as a dose-dependent stimulator of proliferation. This study underscores an mTORC2 and mTORC1 response to the so-called ammonium waste.

The homeodomain-leucine zipper (HD-Zip) class I transcription factors ATHB7 and ATHB12 modulate abscisic acid signalling by regulating protein phosphatase 2C and abscisic acid receptor gene activities.

PubMed

Valdés, Ana Elisa; Overnäs, Elin; Johansson, Henrik; Rada-Iglesias, Alvaro; Engström, Peter

2012-11-01

Plants perceiving drought activate multiple responses to improve survival, including large-scale alterations in gene expression. This article reports on the roles in the drought response of two Arabidopsis thaliana homeodomain-leucine zipper class I genes; ATHB7 and ATHB12, both strongly induced by water-deficit and abscisic acid (ABA). ABA-mediated transcriptional regulation of both genes is shown to depend on the activity of protein phosphatases type 2C (PP2C). ATHB7 and ATHB12 are, thus, targets of the ABA signalling mechanism defined by the PP2Cs and the PYR/PYL family of ABA receptors, with which the PP2C proteins interact. Our results from chromatin immunoprecipitation and gene expression analyses demonstrate that ATHB7 and ATHB12 act as positive transcriptional regulators of PP2C genes, and thereby as negative regulators of abscisic acid signalling. In support of this notion, our results also show that ATHB7 and ATHB12 act to repress the transcription of genes encoding the ABA receptors PYL5 and PYL8 in response to an ABA stimulus. In summary, we demonstrate that ATHB7 and ATHB12 have essential functions in the primary response to drought, as mediators of a negative feedback effect on ABA signalling in the plant response to water deficit.

Thioredoxin reductase regulates AP-1 activity as well as thioredoxin nuclear localization via active cysteines in response to ionizing radiation.

PubMed

Karimpour, Shervin; Lou, Junyang; Lin, Lilie L; Rene, Luis M; Lagunas, Lucio; Ma, Xinrong; Karra, Sreenivasu; Bradbury, C Matthew; Markovina, Stephanie; Goswami, Prabhat C; Spitz, Douglas R; Hirota, Kiichi; Kalvakolanu, Dhananjaya V; Yodoi, Junji; Gius, David

2002-09-12

A recently identified class of signaling factors uses critical cysteine motif(s) that act as redox-sensitive 'sulfhydryl switches' to reversibly modulate specific signal transduction cascades regulating downstream proteins with similar redox-sensitive sites. For example, signaling factors such as redox factor-1 (Ref-1) and transcription factors such as the AP-1 complex both contain redox-sensitive cysteine motifs that regulate activity in response to oxidative stress. The mammalian thioredoxin reductase-1 (TR) is an oxidoreductase selenocysteine-containing flavoprotein that also appears to regulate multiple downstream intracellular redox-sensitive proteins. Since ionizing radiation (IR) induces oxidative stress as well as increases AP-1 DNA-binding activity via the activation of Ref-1, the potential roles of TR and thioredoxin (TRX) in the regulation of AP-1 activity in response to IR were investigated. Permanently transfected cell lines that overexpress wild type TR demonstrated constitutive increases in AP-1 DNA-binding activity as well as AP-1-dependent reporter gene expression, relative to vector control cells. In contrast, permanently transfected cell lines expressing a TR gene with the active site cysteine motif deleted were unable to induce AP-1 activity or reporter gene expression in response to IR. Transient genetic overexpression of either the TR wild type or dominant-negative genes demonstrated similar results using a transient assay system. One mechanism through which TR regulates AP-1 activity appears to involve TRX sub-cellular localization, with no change in the total TRX content of the cell. These results identify a novel function of the TR enzyme as a signaling factor in the regulation of AP-1 activity via a cysteine motif located in the protein.

Bioassays of quorum sensing compounds using Agrobacterium tumefaciens and Chromobacterium violaceum.

PubMed

Chu, Weihua; Vattem, Dhiraj A; Maitin, Vatsala; Barnes, Mary B; McLean, Robert J C

2011-01-01

In most bacteria, a global level of regulation exists involving intercellular communication via the production and response to cell density-dependent signal molecules. This cell density-dependent regulation has been termed quorum sensing (QS). QS is a global regulator, which has been associated with a number of important features in bacteria including virulence regulation and biofilm formation. Consequently, there is considerable interest in understanding, detecting, and inhibiting QS. Acyl homoserine lactones (acyl HSLs) are used as extracellular QS signals by a variety of Gram-negative bacteria. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigment violacein, the production of which is regulated by acyl HSL-mediated QS. Based on this readily observed pigmentation phenotype, C. violaceum strains can be used to detect various aspects of acyl HSL-mediated QS activity. In another commonly used bioassay organism, Agrobacterium tumefaciens, QS can be detected by the use of a reporter gene such as lacZ. Here, we describe several commonly used approaches incorporating C. violaceum and A. tumefaciens that can be used to detect acyl HSLs and QS inhibition.

Heat shock cognate 71 (HSC71) regulates cellular antiviral response by impairing formation of VISA aggregates.

PubMed

Liu, Zhigang; Wu, Shu-Wen; Lei, Cao-Qi; Zhou, Qian; Li, Shu; Shu, Hong-Bing; Wang, Yan-Yi

2013-05-01

In response to viral infection, RIG-I-like RNA helicases detect viral RNA and signal through the mitochondrial adapter protein VISA. VISA activation leads to rapid activation of transcription factors IRF3 and NF-κB, which collaborate to induce transcription of type I interferon (IFN) genes and cellular antiviral response. It has been demonstrated that VISA is activated by forming prion-like aggregates. However, how this process is regulated remains unknown. Here we show that overexpression of HSC71 resulted in potent inhibition of virus-triggered transcription of IFNB1 gene and cellular antiviral response. Consistently, knockdown of HSC71 had opposite effects. HSC71 interacted with VISA, and negatively regulated virus-triggered VISA aggregation. These findings suggest that HSC71 functions as a check against VISA-mediated antiviral response.

Child Temperament Moderates Effects of Parent-Child Mutuality on Self-Regulation: A Relationship-Based Path for Emotionally Negative Infants

PubMed Central

Kim, Sanghag; Kochanska, Grazyna

2012-01-01

This study examined infants’ negative emotionality as moderating the effect of parent-child Mutually Responsive Orientation (MRO) on children’s self-regulation (N=102). Negative emotionality was observed in anger-eliciting episodes and in interactions with parents at 7 months. MRO was coded in naturalistic interactions at 15 months. Self-regulation was measured at 25 months in effortful control battery and as self-regulated compliance to parental requests and prohibitions. Negative emotionality moderated the effects of mother-child MRO. Highly negative infants were less self-regulated when they were in unresponsive relationships (low MRO), but more self-regulated when in responsive relationships (high MRO). For infants not prone to negative emotionality, there was no link between MRO and self-regulation. The “regions-of-significance” analysis supported the differential susceptibility model not the diathesis-stress model. PMID:22670684

Negative Affect as a Mediator of the Relationship between Vigorous-Intensity Exercise and Smoking

PubMed Central

Tart, Candyce D.; Leyro, Teresa M.; Richter, Ashley; Zvolensky, Michael J.; Rosenfield, David; Smits, Jasper A. J.

2010-01-01

The present cross-sectional study evaluated whether people who engage in vigorous-intensity exercise are better able to regulate negative affective states, thereby changing core maintenance factors of smoking. Participants were a community sample of adults (n = 270) who completed self-report measures of physical activity, cigarette smoking, anxiety sensitivity, and negative affect. Consistent with hypothesis, vigorous-intensity exercise was related to lower levels of cigarette smoking, accounting for 10% of the variance in smoking. Additionally, negative affect mediated the relationship between vigorous-intensity physical activity and cigarette smoking, accounting for about 12% of this relation. Furthermore, these relationships were stronger for individuals with high anxiety sensitivity than for those with low anxiety sensitivity; including anxiety sensitivity as a moderator of the mediated relationship increased the amount of variance accounted for by negative affect to 17%. The findings are discussed in relation to developing further scientific insight into the mechanisms and pathways relevant to understanding the association among vigorous-intensity exercise, smoking, and emotional vulnerability. PMID:20171786

Transcription of Two Adjacent Carbohydrate Utilization Gene Clusters in Bifidobacterium breve UCC2003 Is Controlled by LacI- and Repressor Open Reading Frame Kinase (ROK)-Type Regulators

PubMed Central

O'Connell, Kerry Joan; O'Connell Motherway, Mary; Liedtke, Andrea; Fitzgerald, Gerald F.; Ross, R. Paul; Stanton, Catherine; Zomer, Aldert

2014-01-01

Members of the genus Bifidobacterium are commonly found in the gastrointestinal tracts of mammals, including humans, where their growth is presumed to be dependent on various diet- and/or host-derived carbohydrates. To understand transcriptional control of bifidobacterial carbohydrate metabolism, we investigated two genetic carbohydrate utilization clusters dedicated to the metabolism of raffinose-type sugars and melezitose. Transcriptomic and gene inactivation approaches revealed that the raffinose utilization system is positively regulated by an activator protein, designated RafR. The gene cluster associated with melezitose metabolism was shown to be subject to direct negative control by a LacI-type transcriptional regulator, designated MelR1, in addition to apparent indirect negative control by means of a second LacI-type regulator, MelR2. In silico analysis, DNA-protein interaction, and primer extension studies revealed the MelR1 and MelR2 operator sequences, each of which is positioned just upstream of or overlapping the correspondingly regulated promoter sequences. Similar analyses identified the RafR binding operator sequence located upstream of the rafB promoter. This study indicates that transcriptional control of gene clusters involved in carbohydrate metabolism in bifidobacteria is subject to conserved regulatory systems, representing either positive or negative control. PMID:24705323

Lysophosphatidic acid receptor-5 negatively regulates cellular responses in mouse fibroblast 3T3 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Yan; Hirane, Miku; Araki, Mutsumi

2014-04-04

Highlights: • LPA{sub 5} inhibits the cell growth and motile activities of 3T3 cells. • LPA{sub 5} suppresses the cell motile activities stimulated by hydrogen peroxide in 3T3 cells. • Enhancement of LPA{sub 5} on the cell motile activities inhibited by LPA{sub 1} in 3T3 cells. • The expression and activation of Mmp-9 were inhibited by LPA{sub 5} in 3T3 cells. • LPA signaling via LPA{sub 5} acts as a negative regulator of cellular responses in 3T3 cells. - Abstract: Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors (LPA{sub 1}–LPA{sub 6}) mediates a variety of biological functions, including cellmore » migration. Recently, we have reported that LPA{sub 1} inhibited the cell motile activities of mouse fibroblast 3T3 cells. In the present study, to evaluate a role of LPA{sub 5} in cellular responses, Lpar5 knockdown (3T3-L5) cells were generated from 3T3 cells. In cell proliferation assays, LPA markedly stimulated the cell proliferation activities of 3T3-L5 cells, compared with control cells. In cell motility assays with Cell Culture Inserts, the cell motile activities of 3T3-L5 cells were significantly higher than those of control cells. The activity levels of matrix metalloproteinases (MMPs) were measured by gelatin zymography. 3T3-L5 cells stimulated the activation of Mmp-2, correlating with the expression levels of Mmp-2 gene. Moreover, to assess the co-effects of LPA{sub 1} and LPA{sub 5} on cell motile activities, Lpar5 knockdown (3T3a1-L5) cells were also established from Lpar1 over-expressing (3T3a1) cells. 3T3a1-L5 cells increased the cell motile activities of 3T3a1 cells, while the cell motile activities of 3T3a1 cells were significantly lower than those of control cells. These results suggest that LPA{sub 5} may act as a negative regulator of cellular responses in mouse fibroblast 3T3 cells, similar to the case for LPA{sub 1}.« less

Cell cycle-regulated proteolysis of mitotic target proteins.

PubMed

Bastians, H; Topper, L M; Gorbsky, G L; Ruderman, J V

1999-11-01

The ubiquitin-dependent proteolysis of mitotic cyclin B, which is catalyzed by the anaphase-promoting complex/cyclosome (APC/C) and ubiquitin-conjugating enzyme H10 (UbcH10), begins around the time of the metaphase-anaphase transition and continues through G1 phase of the next cell cycle. We have used cell-free systems from mammalian somatic cells collected at different cell cycle stages (G0, G1, S, G2, and M) to investigate the regulated degradation of four targets of the mitotic destruction machinery: cyclins A and B, geminin H (an inhibitor of S phase identified in Xenopus), and Cut2p (an inhibitor of anaphase onset identified in fission yeast). All four are degraded by G1 extracts but not by extracts of S phase cells. Maintenance of destruction during G1 requires the activity of a PP2A-like phosphatase. Destruction of each target is dependent on the presence of an N-terminal destruction box motif, is accelerated by additional wild-type UbcH10 and is blocked by dominant negative UbcH10. Destruction of each is terminated by a dominant activity that appears in nuclei near the start of S phase. Previous work indicates that the APC/C-dependent destruction of anaphase inhibitors is activated after chromosome alignment at the metaphase plate. In support of this, we show that addition of dominant negative UbcH10 to G1 extracts blocks destruction of the yeast anaphase inhibitor Cut2p in vitro, and injection of dominant negative UbcH10 blocks anaphase onset in vivo. Finally, we report that injection of dominant negative Ubc3/Cdc34, whose role in G1-S control is well established and has been implicated in kinetochore function during mitosis in yeast, dramatically interferes with congression of chromosomes to the metaphase plate. These results demonstrate that the regulated ubiquitination and destruction of critical mitotic proteins is highly conserved from yeast to humans.

The AAA protein spastin possesses two levels of basal ATPase activity.

PubMed

Fan, Xiangyu; Lin, Zhijie; Fan, Guanghui; Lu, Jing; Hou, Yongfei; Habai, Gulijiazi; Sun, Linyue; Yu, Pengpeng; Shen, Yuequan; Wen, Maorong; Wang, Chunguang

2018-05-01

The AAA ATPase spastin is a microtubule-severing enzyme that plays important roles in various cellular events including axon regeneration. Herein, we found that the basal ATPase activity of spastin is negatively regulated by spastin concentration. By determining a spastin crystal structure, we demonstrate the necessity of intersubunit interactions between spastin AAA domains. Neutralization of the positive charges in the microtubule-binding domain (MTBD) of spastin dramatically decreases the ATPase activity at low concentration, although the ATP-hydrolyzing potential is not affected. These results demonstrate that, in addition to the AAA domain, the MTBD region of spastin is also involved in regulating ATPase activity, making interactions between spastin protomers more complicated than expected. © 2018 Federation of European Biochemical Societies.

Rab GTPases Regulate Endothelial Cell Protein C Receptor-Mediated Endocytosis and Trafficking of Factor VIIa

PubMed Central

Nayak, Ramesh C.; Keshava, Shiva; Esmon, Charles T.; Pendurthi, Usha R.; Rao, L. Vijaya Mohan

2013-01-01

Recent studies have established that factor VIIa (FVIIa) binds to the endothelial cell protein C receptor (EPCR). FVIIa binding to EPCR may promote the endocytosis of this receptor/ligand complex. Rab GTPases are known to play a crucial role in the endocytic and exocytic pathways of receptors or receptor/ligand complexes. The present study was undertaken to investigate the role of Rab GTPases in the intracellular trafficking of EPCR and FVIIa. CHO-EPCR cells and human umbilical vein endothelial cells (HUVEC) were transduced with recombinant adenoviral vectors to express wild-type, constitutively active, or dominant negative mutant of various Rab GTPases. Cells were exposed to FVIIa conjugated with AF488 fluorescent probe (AF488-FVIIa), and intracellular trafficking of FVIIa, EPCR, and Rab proteins was evaluated by immunofluorescence confocal microscopy. In cells expressing wild-type or constitutively active Rab4A, internalized AF488-FVIIa accumulated in early/sorting endosomes and its entry into the recycling endosomal compartment (REC) was inhibited. Expression of constitutively active Rab5A induced large endosomal structures beneath the plasma membrane where EPCR and FVIIa accumulated. Dominant negative Rab5A inhibited the endocytosis of EPCR-FVIIa. Expression of constitutively active Rab11 resulted in retention of accumulated AF488-FVIIa in the REC, whereas expression of a dominant negative form of Rab11 led to accumulation of internalized FVIIa in the cytoplasm and prevented entry of internalized FVIIa into the REC. Expression of dominant negative Rab11 also inhibited the transport of FVIIa across the endothelium. Overall our data show that Rab GTPases regulate the internalization and intracellular trafficking of EPCR-FVIIa. PMID:23555015

AMP-activated protein kinase is involved in neural stem cell growth suppression and cell cycle arrest by 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside and glucose deprivation by down-regulating phospho-retinoblastoma protein and cyclin D.

PubMed

Zang, Yi; Yu, Li-Fang; Nan, Fa-Jun; Feng, Lin-Yin; Li, Jia

2009-03-06

The fate of neural stem cells (NSCs), including their proliferation, differentiation, survival, and death, is regulated by multiple intrinsic signals and the extrinsic environment. We had previously reported that 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) directly induces astroglial differentiation of NSCs by activation of the Janus kinase (JAK)/Signal transducer and activator of transcription 3 (STAT3) pathway independently of AMP-activated protein kinase (AMPK). Here, we reported the observation that AICAR inhibited NSC proliferation and its underlying mechanism. Analysis of caspase activity and cell cycle showed that AICAR induced G1/G0 cell cycle arrest in NSCs, associated with decreased levels of poly(ADP-ribose) polymerase, phospho-retinoblastoma protein (Rb), and cyclin D but did not cause apoptosis. Iodotubericidin and Compound C, inhibitors of adenosine kinase and AMPK, respectively, or overexpression of a dominant-negative mutant of AMPK, but not JAK inhibitor, were able to reverse the anti-proliferative effect of AICAR. Glucose deprivation also activated the AMPK pathway, induced G0/G1 arrest, and suppressed the proliferation of NSCs, an effect associated with decreased levels of phospho-Rb and cyclin D protein. Furthermore, Compound C and overexpression of dominant-negative AMPK in C17.2 NSCs could block the glucose deprivation-mediated down-regulation of cyclin D and partially reverse the suppression of proliferation. These results suggest that AICAR and glucose deprivation might induce G1/G0 cell cycle arrest and suppress proliferation of NSCs via phospho-Rb and cyclin D down-regulation. AMPK, but not JAK/STAT3, activation is key for this inhibitory effect and may play an important role in the responses of NSCs to metabolic stresses such as glucose deprivation.

Measuring Generalized Expectancies for Negative Mood Regulation.

ERIC Educational Resources Information Center

Catanzaro, Salvatore J.; Mearns, Jack

Research has suggested the utility of studying individual differences in the regulation of negative mood states. Generalized response expectancies for negative mood regulation were defined as expectancies that some overt behavior or cognition would alleviate negative mood states as they occur across situations. The Generalized Expectancy for…

Human myostatin negatively regulates human myoblast growth and differentiation

PubMed Central

McFarlane, Craig; Hui, Gu Zi; Amanda, Wong Zhi Wei; Lau, Hiu Yeung; Lokireddy, Sudarsanareddy; XiaoJia, Ge; Mouly, Vincent; Butler-Browne, Gillian; Gluckman, Peter D.; Sharma, Mridula

2011-01-01

Myostatin, a member of the transforming growth factor-β superfamily, has been implicated in the potent negative regulation of myogenesis in murine models. However, little is known about the mechanism(s) through which human myostatin negatively regulates human skeletal muscle growth. Using human primary myoblasts and recombinant human myostatin protein, we show here that myostatin blocks human myoblast proliferation by regulating cell cycle progression through targeted upregulation of p21. We further show that myostatin regulates myogenic differentiation through the inhibition of key myogenic regulatory factors including MyoD, via canonical Smad signaling. In addition, we have for the first time demonstrated the capability of myostatin to regulate the Notch signaling pathway during inhibition of human myoblast differentiation. Treatment with myostatin results in the upregulation of Hes1, Hes5, and Hey1 expression during differentiation; moreover, when we interfere with Notch signaling, through treatment with the γ-secretase inhibitor L-685,458, we find enhanced myotube formation despite the presence of excess myostatin. Therefore, blockade of the Notch pathway relieves myostatin repression of differentiation, and myostatin upregulates Notch downstream target genes. Immunoprecipitation studies demonstrate that myostatin treatment of myoblasts results in enhanced association of Notch1-intracellular domain with Smad3, providing an additional mechanism through which myostatin targets and represses the activity of the myogenic regulatory factor MyoD. On the basis of these results, we suggest that myostatin function and mechanism of action are very well conserved between species, and that myostatin regulation of postnatal myogenesis involves interactions with numerous downstream signaling mediators, including the Notch pathway. PMID:21508334

Human myostatin negatively regulates human myoblast growth and differentiation.

PubMed

McFarlane, Craig; Hui, Gu Zi; Amanda, Wong Zhi Wei; Lau, Hiu Yeung; Lokireddy, Sudarsanareddy; Xiaojia, Ge; Mouly, Vincent; Butler-Browne, Gillian; Gluckman, Peter D; Sharma, Mridula; Kambadur, Ravi

2011-07-01

Myostatin, a member of the transforming growth factor-β superfamily, has been implicated in the potent negative regulation of myogenesis in murine models. However, little is known about the mechanism(s) through which human myostatin negatively regulates human skeletal muscle growth. Using human primary myoblasts and recombinant human myostatin protein, we show here that myostatin blocks human myoblast proliferation by regulating cell cycle progression through targeted upregulation of p21. We further show that myostatin regulates myogenic differentiation through the inhibition of key myogenic regulatory factors including MyoD, via canonical Smad signaling. In addition, we have for the first time demonstrated the capability of myostatin to regulate the Notch signaling pathway during inhibition of human myoblast differentiation. Treatment with myostatin results in the upregulation of Hes1, Hes5, and Hey1 expression during differentiation; moreover, when we interfere with Notch signaling, through treatment with the γ-secretase inhibitor L-685,458, we find enhanced myotube formation despite the presence of excess myostatin. Therefore, blockade of the Notch pathway relieves myostatin repression of differentiation, and myostatin upregulates Notch downstream target genes. Immunoprecipitation studies demonstrate that myostatin treatment of myoblasts results in enhanced association of Notch1-intracellular domain with Smad3, providing an additional mechanism through which myostatin targets and represses the activity of the myogenic regulatory factor MyoD. On the basis of these results, we suggest that myostatin function and mechanism of action are very well conserved between species, and that myostatin regulation of postnatal myogenesis involves interactions with numerous downstream signaling mediators, including the Notch pathway.

Adolescent Neurodevelopment of Cognitive Control and Risk-taking in Negative Family Contexts

PubMed Central

McCormick, Ethan M.; Qu, Yang; Telzer, Eva H.

2015-01-01

Adolescents have an increased need to regulate their behavior as they gain access to opportunities for risky behavior; however, cognitive control systems necessary for this regulation remain relatively immature. Parents can impact their adolescent child's abilities to regulate their behavior and engagement in risk taking. Since adolescents undergo significant neural change, negative parent-child relationship quality may impede or alter development in prefrontal regions subserving cognitive control. To test this hypothesis, 20 adolescents completed a go/nogo task during two fMRI scans occurring 1 year apart. Adolescents reporting greater family conflict and lower family cohesion showed longitudinal increases in risk-taking behavior, which was mediated by longitudinal increases in left VLPFC activation during cognitive control. These results underscore the importance of parent-child relationships during early adolescence, and the neural processes by which cognitive control may be derailed and lead to increased risk taking. PMID:26434803

Adolescent neurodevelopment of cognitive control and risk-taking in negative family contexts.

PubMed

McCormick, Ethan M; Qu, Yang; Telzer, Eva H

2016-01-01

Adolescents have an increased need to regulate their behavior as they gain access to opportunities for risky behavior; however, cognitive control systems necessary for this regulation remain relatively immature. Parents can impact their adolescent child's abilities to regulate their behavior and engagement in risk taking. Since adolescents undergo significant neural change, negative parent-child relationship quality may impede or alter development in prefrontal regions subserving cognitive control. To test this hypothesis, 20 adolescents completed a Go/NoGo task during two fMRI scans occurring 1year apart. Adolescents reporting greater family conflict and lower family cohesion showed longitudinal increases in risk-taking behavior, which was mediated by longitudinal increases in left VLPFC activation during cognitive control. These results underscore the importance of parent-child relationships during early adolescence, and the neural processes by which cognitive control may be derailed and may lead to increased risk taking. Published by Elsevier Inc.

Molecular Dynamic Simulation Insights into the Normal State and Restoration of p53 Function

PubMed Central

Fu, Ting; Min, Hanyi; Xu, Yong; Chen, Jianzhong; Li, Guohui

2012-01-01

As a tumor suppressor protein, p53 plays a crucial role in the cell cycle and in cancer prevention. Almost 50 percent of all human malignant tumors are closely related to a deletion or mutation in p53. The activity of p53 is inhibited by over-active celluar antagonists, especially by the over-expression of the negative regulators MDM2 and MDMX. Protein-protein interactions, or post-translational modifications of the C-terminal negative regulatory domain of p53, also regulate its tumor suppressor activity. Restoration of p53 function through peptide and small molecular inhibitors has become a promising strategy for novel anti-cancer drug design and development. Molecular dynamics simulations have been extensively applied to investigate the conformation changes of p53 induced by protein-protein interactions and protein-ligand interactions, including peptide and small molecular inhibitors. This review focuses on the latest MD simulation research, to provide an overview of the current understanding of interactions between p53 and its partners at an atomic level. PMID:22949826

Effects of valence and divided attention on cognitive reappraisal processes

PubMed Central

Leclerc, Christina M.; Kensinger, Elizabeth A.

2014-01-01

Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources. PMID:24493837

Suppression of telomere-binding protein TPP1 resulted in telomere dysfunction and enhanced radiation sensitivity in telomerase-negative osteosarcoma cell line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiang, Weiguang; Department of Oncology, The Third Affiliated Hospital, Soochow University, Changzhou; Wu, Qinqin

Highlights: • Down-regulation of TPP1 shortened telomere length in telomerase-negative cells. • Down-regulation of TPP1 induced cell apoptosis in telomerase-negative cells. • Down-regulation of TPP1 increased radiosensitivity in telomerase-negative cells. - Abstract: Mammalian telomeres are protected by the shelterin complex that contains the six core proteins POT1, TPP1, TIN2, TRF1, TRF2 and RAP1. TPP1, formerly known as TINT1, PTOP, and PIP1, is a key factor that regulates telomerase recruitment and activity. In addition to this, TPP1 is required to mediate the shelterin assembly and stabilize telomere. Previous work has found that TPP1 expression was elevated in radioresistant cells and thatmore » overexpression of TPP1 led to radioresistance and telomere lengthening in telomerase-positive cells. However, the exact effects and mechanism of TPP1 on radiosensitivity are yet to be precisely defined in the ALT cells. Here we report on the phenotypes of the conditional deletion of TPP1 from the human osteosarcoma U2OS cells using ALT pathway to extend the telomeres.TPP1 deletion resulted in telomere shortening, increased apoptosis and radiation sensitivity enhancement. Together, our findings show that TPP1 plays a vital role in telomere maintenance and protection and establish an intimate relationship between TPP1, telomere and cellular response to ionizing radiation, but likely has the specific mechanism yet to be defined.« less

JAK2-V617F-induced MAPK activity is regulated by PI3K and acts synergistically with PI3K on the proliferation of JAK2-V617F-positive cells

PubMed Central

Wolf, Alexandra; Eulenfeld, René; Gäbler, Karoline; Rolvering, Catherine; Haan, Serge; Behrmann, Iris; Denecke, Bernd; Haan, Claude; Schaper, Fred

2013-01-01

The identification of a constitutively active JAK2 mutant, namely JAK2-V617F, was a milestone in the understanding of Philadelphia chromosome-negative myeloproliferative neoplasms. The JAK2-V617F mutation confers cytokine hypersensitivity, constitutive activation of the JAK-STAT pathway, and cytokine-independent growth. In this study we investigated the mechanism of JAK2-V617F-dependent signaling with a special focus on the activation of the MAPK pathway. We observed JAK2-V617F-dependent deregulated activation of the multi-site docking protein Gab1 as indicated by constitutive, PI3K-dependent membrane localization and tyrosine phosphorylation of Gab1. Furthermore, we demonstrate that PI3K signaling regulates MAPK activation in JAK2-V617F-positve cells. This cross-regulation of the MAPK pathway by PI3K affects JAK2-V617F-specific target gene induction, erythroid colony formation, and regulates proliferation of JAK2-V617F-positive patient cells in a synergistically manner. PMID:24069558

miR-219-1-3p is a negative regulator of the mucin MUC4 expression and is a tumor suppressor in pancreatic cancer.

PubMed

Lahdaoui, F; Delpu, Y; Vincent, A; Renaud, F; Messager, M; Duchêne, B; Leteurtre, E; Mariette, C; Torrisani, J; Jonckheere, N; Van Seuningen, I

2015-02-05

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers in the world with one of the worst outcome. The oncogenic mucin MUC4 has been identified as an actor of pancreatic carcinogenesis as it is involved in many processes regulating pancreatic cancer cell biology. MUC4 is not expressed in healthy pancreas whereas it is expressed very early in pancreatic carcinogenesis. Targeting MUC4 in these early steps may thus appear as a promising strategy to slow-down pancreatic tumorigenesis. miRNA negative regulation of MUC4 could be one mechanism to efficiently downregulate MUC4 gene expression in early pancreatic neoplastic lesions. Using in silico studies, we found two putative binding sites for miR-219-1-3p in the 3'-UTR of MUC4 and showed that miR-219-1-3p expression is downregulated both in PDAC-derived cell lines and human PDAC tissues compared with their normal counterparts. We then showed that miR-219-1-3p negatively regulates MUC4 mucin expression via its direct binding to MUC4 3'-UTR. MiR-219-1-3p overexpression (transient and stable) in pancreatic cancer cell lines induced a decrease of cell proliferation associated with a decrease of cyclin D1 and a decrease of Akt and Erk pathway activation. MiR-219-1-3p overexpression also decreased cell migration. Furthermore, miR-219-1-3p expression was found to be conversely correlated with Muc4 expression in early pancreatic intraepithelial neoplasia lesions of Pdx1-Cre;LSL-Kras(G12D) mice. Most interestingly, in vivo studies showed that miR-219-1-3p injection in xenografted pancreatic tumors in mice decreased both tumor growth and MUC4 mucin expression. Altogether, these results identify miR-219-1-3p as a new negative regulator of MUC4 oncomucin that possesses tumor-suppressor activity in PDAC.

Signaling by STATs.

PubMed

Ivashkiv, Lionel B; Hu, Xiaoyu

2004-01-01

A variety of cytokines and growth factors use the Janus kinase (Jak)-STAT signaling pathway to transmit extracellular signals to the nucleus. STATs (signal transducers and activators of transcription) are latent cytoplasmic transcription factors. There are seven mammalian STATs and they have critical, nonredundant roles in mediating cellular transcriptional responses to cytokines. The physiological roles of STATs have been elucidated by analysis of mice rendered deficient in STAT genes. STAT activation is regulated and can be modulated in a positive or negative fashion; it can be reprogrammed to drive different cellular responses. Several auto-regulatory and signaling crosstalk mechanisms for regulating Jak-STAT signaling have been described. Understanding and manipulation of the function of STATs will help in the development of therapeutic strategies for diseases that are regulated by cytokines.

Post-translational regulation of WRKY transcription factors in plant immunity.

PubMed

Ishihama, Nobuaki; Yoshioka, Hirofumi

2012-08-01

Plants have evolved immune system to protect themselves against invading pathogens. Recent research has illustrated that signaling networks, after perception of diverse pathogen-derived signals, facilitate transcriptional reprogramming through mitogen-activated protein kinase (MAPK) cascades. WRKY proteins, which comprise a large family of plant transcription factors, are key players in plant immune responses. WRKY transcription factors participate in the control of defense-related genes either as positive or as negative regulators, and essentially are regulated at the transcriptional level. Emerging evidence emphasizes that group I WRKY transcription factors, which contain a conserved motif in the N-terminal region, are also activated by MAPK-dependent phosphorylation, underlining their importance in plant immunity. Copyright © 2012 Elsevier Ltd. All rights reserved.

An fMRI investigation of the cognitive reappraisal of negative memories

PubMed Central

Holland, Alisha C.; Kensinger, Elizabeth A.

2013-01-01

Episodic memory retrieval can be influenced by individuals’ current goals, including those that are emotional in nature. Participants underwent an fMRI scan while reappraising, or changing the way they thought about aversive images they had previously encoded, to down-regulate (i.e., decrease), up-regulate (i.e., increase), or maintain the emotional intensity associated with their recall. A conjunction analysis between down- and up-regulation during the entire 12-sec recall period revealed that both commonly activated reappraisal-related regions, particularly in the lateral and medial prefrontal cortex (PFC). However, when we analyzed a reappraisal instruction phase prior to recall and then divided the recall phase into the time when individuals were first searching for their memories and later elaborating on their details, we found that down- and up-regulation engaged greater neural activity at different time points. Up-regulation engaged greater PFC activity than down-regulation or maintenance during the reappraisal instruction phase. In contrast, down-regulation engaged greater lateral PFC activity as images were being searched for and retrieved. Maintaining the emotional intensity associated with the aversive images engaged similar regions to a greater extent than either reappraisal condition as participants elaborated on the details of the images they were holding in mind. Our findings suggest that down- and up-regulation engage similar neural regions during memory retrieval, but differ in the timing of this engagement. PMID:23500898

Emotion dysregulation and negative affect: Laboratory and EMA investigations in smokers.

PubMed

MacIntyre, Jessica M; Ruscio, Aimee C; Brede, Emily; Waters, Andrew J

2018-06-01

Difficulties in emotion regulation are associated with addictive behaviors, including smoking. Difficulties in emotion regulation may underlie large, rapid changes in negative affect that can increase likelihood of relapse. We investigated the association between emotion regulation ability and negative affect in smokers assessed both in the laboratory and in the field using Ecological Momentary Assessment. Adult community smokers ( N  = 44) carried a personal digital assistant (PDA) for two weeks and were instructed to complete assessments of negative affect multiple times per day. Participants were instructed that they could smoke as much or as little as they liked. The Difficulties in Emotion Regulation Scale (DERS) and the Positive and Negative Affect Schedule (PANAS) were completed at three lab visits. Participants with higher average DERS scores reported greater negative affect at lab visits. When a participant reported a DERS score at a lab visit higher than their individual average, they also reported higher negative affect at that lab visit. Participants with higher baseline DERS scores reported more labile negative affect during EMA than those with lower baseline DERS scores, and they also reported a higher maximum level of negative affect during EMA. Overall, the findings suggest that changes in emotion regulation are associated with negative affect and that emotion regulation ability is related to both the intensity and lability of negative affect. A better understanding of momentary changes in emotion regulation and negative affect may lead to improved interventions for preventing substance use relapse.

Negative Regulation of Violacein Biosynthesis in Chromobacterium violaceum.

PubMed

Devescovi, Giulia; Kojic, Milan; Covaceuszach, Sonia; Cámara, Miguel; Williams, Paul; Bertani, Iris; Subramoni, Sujatha; Venturi, Vittorio

2017-01-01

In Chromobacteium violaceum , the purple pigment violacein is under positive regulation by the N -acylhomoserine lactone CviI/R quorum sensing system and negative regulation by an uncharacterized putative repressor. In this study we report that the biosynthesis of violacein is negatively controlled by a novel repressor protein, VioS. The violacein operon is regulated negatively by VioS and positively by the CviI/R system in both C. violaceum and in a heterologous Escherichia coli genetic background. VioS does not regulate the CviI/R system and apart from violacein, VioS, and quorum sensing regulate other phenotypes antagonistically. Quorum sensing regulated phenotypes in C. violaceum are therefore further regulated providing an additional level of control.

Effects of salience-network-node neurofeedback training on affective biases in major depressive disorder.

PubMed

Hamilton, J Paul; Glover, Gary H; Bagarinao, Epifanio; Chang, Catie; Mackey, Sean; Sacchet, Matthew D; Gotlib, Ian H

2016-03-30

Neural models of major depressive disorder (MDD) posit that over-response of components of the brain's salience network (SN) to negative stimuli plays a crucial role in the pathophysiology of MDD. In the present proof-of-concept study, we tested this formulation directly by examining the affective consequences of training depressed persons to down-regulate response of SN nodes to negative material. Ten participants in the real neurofeedback group saw, and attempted to learn to down-regulate, activity from an empirically identified node of the SN. Ten other participants engaged in an equivalent procedure with the exception that they saw SN-node neurofeedback indices from participants in the real neurofeedback group. Before and after scanning, all participants completed tasks assessing emotional responses to negative scenes and to negative and positive self-descriptive adjectives. Compared to participants in the sham-neurofeedback group, from pre- to post-training, participants in the real-neurofeedback group showed a greater decrease in SN-node response to negative stimuli, a greater decrease in self-reported emotional response to negative scenes, and a greater decrease in self-reported emotional response to negative self-descriptive adjectives. Our findings provide support for a neural formulation in which the SN plays a primary role in contributing to negative cognitive biases in MDD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Individual differences in self-reported self-control predict successful emotion regulation.

PubMed

Paschke, Lena M; Dörfel, Denise; Steimke, Rosa; Trempler, Ima; Magrabi, Amadeus; Ludwig, Vera U; Schubert, Torsten; Stelzel, Christine; Walter, Henrik

2016-08-01

Both self-control and emotion regulation enable individuals to adapt to external circumstances and social contexts, and both are assumed to rely on the overlapping neural resources. Here, we tested whether high self-reported self-control is related to successful emotion regulation on the behavioral and neural level. One hundred eight participants completed three self-control questionnaires and regulated their negative emotions during functional magnetic resonance imaging using reappraisal (distancing). Trait self-control correlated positively with successful emotion regulation both subjectively and neurally, as indicated by online ratings of negative emotions and functional connectivity strength between the amygdala and prefrontal areas, respectively. This stronger overall connectivity of the left amygdala was related to more successful subjective emotion regulation. Comparing amygdala activity over time showed that high self-controllers successfully maintained down-regulation of the left amygdala over time, while low self-controllers failed to down-regulate towards the end of the experiment. This indicates that high self-controllers are better at maintaining a motivated state supporting emotion regulation over time. Our results support assumptions concerning a close relation of self-control and emotion regulation as two domains of behavioral control. They further indicate that individual differences in functional connectivity between task-related brain areas directly relate to differences in trait self-control. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

SOCS3

PubMed Central

Yasukawa, Hideo; Nagata, Takanobu; Oba, Toyoharu; Imaizumi, Tsutomu

2012-01-01

The suppressors of cytokine signaling (SOCS) family of proteins are cytokine-inducible inhibitors of Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) signaling pathways. Among the family, SOCS1 and SOCS3 potently suppress cytokine actions by inhibiting JAK kinase activities. The generation of mice lacking individual SOCS genes has been instrumental in defining the role of individual SOCS proteins in specific cytokine pathways in vivo; SOCS1 is an essential negative regulator of interferon-γ (IFNγ) and SOCS3 is an essential negative regulator of leukemia inhibitory factor (LIF). JAK-STAT3 activating cytokines have exhibited cardioprotective roles in the heart. The cardiac-specific deletion of SOCS3 enhances the activation of cardioprotective signaling pathways, inhibits myocardial apoptosis and fibrosis and results in the inhibition of left ventricular remodeling after myocardial infarction (MI). We propose that myocardial SOCS3 is a key determinant of left ventricular remodeling after MI, and SOCS3 may serve as a novel therapeutic target to prevent left ventricular remodeling after MI. In this review, we discuss the signaling pathways mediated by JAK-STAT and SOCS proteins and their roles in the development of myocardial injury under stress (e.g., pressure overload, viral infection and ischemia). PMID:24058778

THRAP3 interacts with and inhibits the transcriptional activity of SOX9 during chondrogenesis.

PubMed

Sono, Takashi; Akiyama, Haruhiko; Miura, Shigenori; Deng, Jian Min; Shukunami, Chisa; Hiraki, Yuji; Tsushima, Yu; Azuma, Yoshiaki; Behringer, Richard R; Matsuda, Shuichi

2018-07-01

Sex-determining region Y (Sry)-box (Sox)9 is required for chondrogenesis as a transcriptional activator of genes related to chondrocyte proliferation, differentiation, and cartilage-specific extracellular matrix. Although there have been studies investigating the Sox9-dependent transcriptional complexes, not all their components have been identified. In the present study, we demonstrated that thyroid hormone receptor-associated protein (THRAP)3 is a component of a SOX9 transcriptional complex by liquid chromatography mass spectrometric analysis of FLAG-tagged Sox9-binding proteins purified from FLAG-HA-tagged Sox9 knock-in mice. Thrap3 knockdown in ATDC5 chondrogenic cells increased the expression of Collagen type II alpha 1 chain (Col2a1) without affecting Sox9 expression. THRAP3 and SOX9 overexpression reduced Col2a1 levels to a greater degree than overexpression of SOX9 alone. The negative regulation of SOX9 transcriptional activity by THRAP3 was mediated by interaction between the proline-, glutamine-, and serine-rich domain of SOX9 and the innominate domain of THRAP3. These results indicate that THRAP3 negatively regulates SOX9 transcriptional activity as a cofactor of a SOX9 transcriptional complex during chondrogenesis.

A Longitudinal Study of Emotion Regulation, Emotion Lability/Negativity, and Internalizing Symptomatology in Maltreated and Nonmaltreated Children

PubMed Central

Kim-Spoon, Jungmeen; Cicchetti, Dante; Rogosch, Fred A.

2013-01-01

The longitudinal contributions of emotion regulation and emotion lability/negativity to internalizing symptomatology were examined in a low-income sample (171 maltreated and 151 nonmaltreated children, from age 7 to 10 years). Latent difference score models indicated that, for both maltreated and nonmaltreated children, emotion regulation was a mediator between emotion lability/negativity and internalizing symptomatology, whereas emotion lability/negativity was not a mediator between emotion regulation and internalizing symptomatology. Early maltreatment was associated with high emotion lability/negativity (age 7) that contributed to poor emotion regulation (age 8), which in turn was predictive of increases in internalizing symptomatology (from age 8 to 9). The results imply important roles of emotion regulation in the development of internalizing symptomatology, especially for children with high emotion lability/negativity. PMID:23034132

Distinct regulatory functions of SLP-76 and MIST in NK cell cytotoxicity and IFN-gamma production.

PubMed

Hidano, Shinya; Sasanuma, Hiroki; Ohshima, Keiko; Seino, Ken-ichiro; Kumar, Lalit; Hayashi, Katsuhiko; Hikida, Masaki; Kurosaki, Tomohiro; Taniguchi, Masaru; Geha, Raif S; Kitamura, Daisuke; Goitsuka, Ryo

2008-03-01

Activation of NK cells is triggered by multiple receptors. We demonstrate here that SLP-76 is required for CD16- and NKG2D-mediated NK cell cytotoxicity, while MIST negatively regulates these responses in an SLP-76-dependent manner. Exceptionally, MIST acts as a positive regulator of cytotoxicity against YAC-1 cells, although SLP-76 plays a more key role. SLP-76 acts as a dominant positive regulator for both NKG2D-mediated and YAC-1 cell-triggered IFN-gamma production. Although NKG2D-mediated IFN-gamma production depends on phospholipase C (PLC) gamma 2, YAC-1 cell-triggered IFN-gamma production is PLC gamma 2- and Syk/ZAP-70 independent and nuclear factor-kappa B mediated. SLP-76 is required for this process in the presence of MIST but is dispensable in the absence of MIST. Thus, YAC-1 cell-triggered NKG2D-independent IFN-gamma production appears to be regulated by SLP-76-dependent and -independent pathways, in which the latter is negatively regulated by MIST. Taken together, these results suggest that SLP-76 and MIST distinctly but interactively regulate NK cell cytotoxicity and IFN-gamma production.

DR2539 is a novel DtxR-like regulator of Mn/Fe ion homeostasis and antioxidant enzyme in Deinococcus radiodurans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Huan; Zhejiang Institute of Microbiology, Zhejiang Province, Hangzhou 310012; Wu, Rongrong

2010-05-28

Transcriptional regulators of the diphtheria toxin repressor (DtxR) family control the expression of genes involved in the uptake of iron and manganese, which is not only necessitous nutrients but also was suggested to be essential for intracellular redox cycling of microorganisms. We identified a unique DtxR homologue (DR2539) with special characteristics from Deinococcus radiodurans, which is known for its extreme resistance to radiation and oxidants. The dr2539 mutant showed higher resistance to hydrogen peroxide than the wild-type strain R1. Intracellular catalase activity assay and semiquantitative PCR analysis demonstrated that this DtxR is a negative regulator of catalase (katE). Furthermore, quantitativemore » real-time PCR, global transcription profile and inductively coupled plasma-mass spectrometry analysis showed that the DtxR is involved in the regulation of antioxidant system by maintaining the intracellular Mn/Fe ion homeostasis of D. radiodurans. However, unlike the other DtxR homologues, the DtxR of D. radiodurans acts as a negative regulator of a Mn transporter gene (dr2283) and as a positive regulator of Fe-dependent transporter genes (dr1219, drb0125) in D. radiodurans.« less

Emotionally laden impulsivity interacts with affect in predicting addictive use of online sexual activity in men.

PubMed

Wéry, Aline; Deleuze, Jory; Canale, Natale; Billieux, Joël

2018-01-01

The interest in studying addictive use of online sexual activities (OSA) has grown sharply over the last decade. Despite the burgeoning number of studies conceptualizing the excessive use of OSA as an addictive disorder, few have tested its relations to impulsivity, which is known to constitute a hallmark of addictive behaviors. To address this missing gap in the literature, we tested the relationships between addictive OSA use, impulsivity traits, and affect among a convenience sample of men (N=182; age, M=29.17, SD = 9.34), building upon a theoretically driven model that distinguishes the various facets of impulsivity. Results showed that negative urgency (an impulsivity trait reflecting the tendency to act rashly in negative emotional states) and negative affect interact in predicting addictive OSA use. These results highlight the pivotal role played by negative urgency and negative affect in addictive OSA use, supporting the relevance of psychological interventions that focus on improving emotional regulation (e.g., to reduce negative affect and learn healthier coping strategies) to mitigate excessive use of OSA. Copyright © 2017 Elsevier Inc. All rights reserved.

Surface topography regulates wnt signaling through control of primary cilia structure in mesenchymal stem cells

PubMed Central

McMurray, R. J.; Wann, A. K. T.; Thompson, C. L.; Connelly, J. T.; Knight, M. M.

2013-01-01

The primary cilium regulates cellular signalling including influencing wnt sensitivity by sequestering β-catenin within the ciliary compartment. Topographic regulation of intracellular actin-myosin tension can control stem cell fate of which wnt is an important mediator. We hypothesized that topography influences mesenchymal stem cell (MSC) wnt signaling through the regulation of primary cilia structure and function. MSCs cultured on grooves expressed elongated primary cilia, through reduced actin organization. siRNA inhibition of anterograde intraflagellar transport (IFT88) reduced cilia length and increased active nuclear β-catenin. Conversely, increased primary cilia assembly in MSCs cultured on the grooves was associated with decreased levels of nuclear active β-catenin, axin-2 induction and proliferation, in response to wnt3a. This negative regulation, on grooved topography, was reversed by siRNA to IFT88. This indicates that subtle regulation of IFT and associated cilia structure, tunes the wnt response controlling stem cell differentiation. PMID:24346024

Repression of PDGF-R-α after cellular injury involves TNF-α, formation of a c-Fos-YY1 complex, and negative regulation by HDAC.

PubMed

Zhang, Ning; Chan, Cecilia W S; Sanchez-Guerrero, Estella; Khachigian, Levon M

2012-06-01

Wound healing is a complex dynamic process involving a variety of cell types, including fibroblasts that express and respond to cytokines and growth factors in the local microenvironment. The mechanisms controlling gene expression after injury at a transcriptional level are poorly understood. Here we show that decreased expression of a key receptor, PDGF-receptor (R)-α, after fibroblast injury is due to the release and paracrine activity of TNF-α. TNF-α inhibits PDGF-R-α expression and this involves formation of a c-Fos-Yin Yang 1 (YY1) complex and histone deacetylase (HDAC) activity. c-Fos, induced by TNF-α, negatively regulates PDGF-R-α transcription. Small interfering RNA (siRNA) targeting c-Fos or the zinc finger transcription factor YY1 inhibits TNF-α suppression of PDGF-R-α expression. Coimmunoprecipitation studies show that TNF-α stimulates the formation of a complex between c-Fos with YY1. Furthermore, chromatin immunoprecipitation (ChIP) analysis reveals the enrichment of c-Fos, YY1, and HDAC-1 at the PDGF-R-α promoter in cells exposed to TNF-α. With suberoylanilide hydroxamic acid (SAHA) and HDAC-1 siRNA, we demonstrate that HDAC mediates TNF-α repression of PDGF-R-α. These findings demonstrate that transcriptional repression of PDGF-R-α after fibroblast injury involves paracrine activity of endogenous TNF-α, the formation of a c-Fos-YY1 complex, and negative regulatory activity by HDAC.

TGF-beta1 modulates focal adhesion kinase expression in rat intestinal epithelial IEC-6 cells via stimulatory and inhibitory Smad binding elements.

PubMed

Walsh, Mary F; Ampasala, Dinakar R; Rishi, Arun K; Basson, Marc D

2009-02-01

TGF-beta and FAK modulate cell migration, differentiation, proliferation and apoptosis, and TGF-beta promotes FAK transcription in intestinal epithelial cells via Smad-dependent and independent pathways. We utilized a 1320 bp FAK promoter-luciferase construct to characterize basal and TGF-beta-mediated FAK gene transcription in IEC-6 cells. Inhibiting JNK or Akt negated TGF-beta-stimulated promoter activity; ERK inhibition did not block the TGF-beta effect but increased basal activity. Co-transfection with Co-Smad4 enhanced the TGF-beta response while the inhibitory Smad7 abolished it. Serial deletions sequentially removing the four Smad binding elements (SBE) in the 5' untranslated region of the promoter revealed that the two most distal SBE's are positive regulators while SBE3 exerts a negative influence. Mutational deletion of two upstream p53 sites enhanced basal but did not affect TGF-beta-stimulated increases in promoter activity. TGF-beta increased DNA binding of Smad4, phospho-Smad2/3 and Runx1/AML1a to the most distal 435 bp containing 3 SBE and 2 AML1a sites by ChIP assay. However, although point mutation of SBE1 ablated the TGF-beta-mediated rise in SV40-promoter activity, mutation of AML1a sites did not. TGF-beta regulation of FAK transcription reflects a complex interplay between positive and negative non-Smad signals and SBE's, the last independent of p53 or AML1a.

Expression of alkyl hydroperoxide reductase is regulated negatively by OxyR1 and positively by RpoE2 sigma factor in Azospirillum brasilense Sp7.

PubMed

Singh, Sudhir; Dwivedi, Susheel Kumar; Singh, Vijay Shankar; Tripathi, Anil Kumar

2016-10-01

OxyR proteins are LysR-type transcriptional regulators, which play an important role in responding to oxidative stress in bacteria. Azospirillum brasilense Sp7 harbours two copies of OxyR. The inactivation of the oxyR1, the gene organized divergently to ahpC in A. brasilense Sp7, led to an increased tolerance to alkyl hydroperoxides, which was corroborated by an increase in alkyl hydroperoxide reductase (AhpC) activity, enhanced expression of ahpC :lacZ fusion and increased synthesis of AhpC protein in the oxyR1::km mutant. The upstream region of ahpC promoter harboured a putative OxyR binding site, T-N11-A. Mutation of T, A or both in the T-N11-Amotif caused derepression of ahpC in A. brasilense suggesting that T-N11-A might be the binding site for a negative regulator. Retardation of the electrophoretic mobility of the T-N11-A motif harbouring oxyR1-ahpC intergenic DNA by recombinant OxyR1, under reducing as well as oxidizing conditions, indicated that OxyR1 acts as a negative regulator of ahpC in A. brasilense. Sequence of the promoter of ahpC, predicted on the basis of transcriptional start site, and an enhanced expression of ahpC:lacZ fusion in chrR2::km mutant background suggested that ahpC promoter was RpoE2 dependent. Thus, this study shows that in A. brasilense Sp7, ahpC expression is regulated negatively by OxyR1 but is regulated positively by RpoE2, an oxidative-stress-responsive sigma factor. It also shows that OxyR1 regulates the expression RpoE1, which is known to play an important role during photooxidative stress in A. brasilense.

Sirt1 carboxyl-domain is an ATP-repressible domain that is transferrable to other proteins

PubMed Central

Kang, Hyeog; Oka, Shinichi; Lee, Duck-Yeon; Park, Junhong; Aponte, Angel M.; Jung, Young-Sang; Bitterman, Jacob; Zhai, Peiyong; He, Yi; Kooshapur, Hamed; Ghirlando, Rodolfo; Tjandra, Nico; Lee, Sean B.; Kim, Myung K.; Sadoshima, Junichi; Chung, Jay H.

2017-01-01

Sirt1 is an NAD+-dependent protein deacetylase that regulates many physiological functions, including stress resistance, adipogenesis, cell senescence and energy production. Sirt1 can be activated by energy deprivation, but the mechanism is poorly understood. Here, we report that Sirt1 is negatively regulated by ATP, which binds to the C-terminal domain (CTD) of Sirt1. ATP suppresses Sirt1 activity by impairing the CTD's ability to bind to the deacetylase domain as well as its ability to function as the substrate recruitment site. ATP, but not NAD+, causes a conformational shift to a less compact structure. Mutations that prevent ATP binding increase Sirt1's ability to promote stress resistance and inhibit adipogenesis under high-ATP conditions. Interestingly, the CTD can be attached to other proteins, thereby converting them into energy-regulated proteins. These discoveries provide insight into how extreme energy deprivation can impact Sirt1 activity and underscore the complex nature of Sirt1 structure and regulation. PMID:28504272

The ribonuclease activity of SAMHD1 is required for HIV-1 restriction

PubMed Central

Ryoo, Jeongmin; Choi, Jongsu; Oh, Changhoon; Kim, Sungchul; Seo, Minji; Kim, Seokyoung; Seo, Daekwan; Kim, Jongkyu; White, Tommy E.; Brandariz-Nunez, Alberto; Diaz-Griffero, Felipe; Yun, Cheol-Heui; Hollenbaugh, Joseph A.; Kim, Baek; Baek, Daehyun

2015-01-01

The HIV-1 restriction factor SAMHD11,2 is proposed to inhibit HIV-1 replication by depleting the intracellular dNTP pool3-5. However, the phosphorylation of SAMHD1 regulates its ability to restrict HIV-1 without decreasing cellular dNTP levels6-8, which is not consistent with a role for SAMHD1 dNTPase activity in HIV-1 restriction. Here, we show that SAMHD1 possesses RNase activity and that the RNase but not the dNTPase function is essential for HIV-1 restriction. By enzymatically characterizing Aicardi-Goutières syndrome (AGS)-associated SAMHD1 mutations and mutations in the allosteric dGTP-binding site of SAMHD1, we identify SAMHD1 mutants that are RNase-positive but dNTPase-negative (SAMHD1D137N) or RNase-negative but dNTPase-positive (SAMHD1Q548A). The allosteric mutant SAMHD1D137N is able to restrict HIV-1 infection, whereas the AGS mutant SAMHD1Q548A is defective for HIV-1 restriction. SAMHD1 associates with HIV-1 RNA and degrades it during the early phases of infection. SAMHD1 silencing in macrophages and CD4+ T cells from healthy donors increases HIV-1 RNA stability, rendering the cells permissive for HIV-1 infection. Furthermore, the phosphorylation of SAMHD1 at T592 negatively regulates its RNase activity in vivo and impedes HIV-1 restriction. Our results reveal that the RNase activity of SAMHD1 is responsible for preventing HIV-1 infection by directly degrading the HIV-1 RNA. PMID:25038827

Biochemical and functional analysis of CTR1, a protein kinase that negatively regulates ethylene signaling in Arabidopsis

NASA Technical Reports Server (NTRS)

Huang, Yafan; Li, Hui; Hutchison, Claire E.; Laskey, James; Kieber, Joseph J.

2003-01-01

CTR1 encodes a negative regulator of the ethylene response pathway in Arabidopsis thaliana. The C-terminal domain of CTR1 is similar to the Raf family of protein kinases, but its first two-thirds encodes a novel protein domain. We used a variety of approaches to investigate the function of these two CTR1 domains. Recombinant CTR1 protein was purified from a baculoviral expression system, and shown to possess intrinsic Ser/Thr protein kinase activity with enzymatic properties similar to Raf-1. Deletion of the N-terminal domain did not elevate the kinase activity of CTR1, indicating that, at least in vitro, this domain does not autoinhibit kinase function. Molecular analysis of loss-of-function ctr1 alleles indicated that several mutations disrupt the kinase catalytic domain, and in vitro studies confirmed that at least one of these eliminates kinase activity, which indicates that kinase activity is required for CTR1 function. One missense mutation, ctr1-8, was found to result from an amino acid substitution within a new conserved motif within the N-terminal domain. Ctr1-8 has no detectable effect on the kinase activity of CTR1 in vitro, but rather disrupts the interaction with the ethylene receptor ETR1. This mutation also disrupts the dominant negative effect that results from overexpression of the CTR1 amino-terminal domain in transgenic Arabidopsis. These results suggest that CTR1 interacts with ETR1 in vivo, and that this association is required to turn off the ethylene-signaling pathway.

Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism

PubMed Central

Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

2016-01-01

Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape. PMID:27097688

Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism.

PubMed

Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

2016-04-21

Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape.

E3 Ubiquitin Ligase c-cbl Inhibits Microglia Activation After Chronic Constriction Injury.

PubMed

Xue, Pengfei; Liu, Xiaojuan; Shen, Yiming; Ju, Yuanyuan; Lu, Xiongsong; Zhang, Jinlong; Xu, Guanhua; Sun, Yuyu; Chen, Jiajia; Gu, Haiyan; Cui, Zhiming; Bao, Guofeng

2018-06-22

E3 ubiquitin ligase c-Caritas B cell lymphoma (c-cbl) is associated with negative regulation of receptor tyrosine kinases, signal transduction of antigens and cytokine receptors, and immune response. However, the expression and function of c-cbl in the regulation of neuropathic pain after chronic constriction injury (CCI) are unknown. In rat CCI model, c-cbl inhibited the activation of spinal cord microglia and the release of pro-inflammatory factors including tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6), which alleviated mechanical and heat pain through down-regulating extracellular signal-regulated kinase (ERK) pathway. Additionally, exogenous TNF-α inhibited c-cbl protein level vice versa. In the primary microglia transfected with c-cbl siRNA, when treated with TNF-α or TNF-α inhibitor, the corresponding secretion of IL-1β and IL-6 did not change. In summary, CCI down-regulated c-cbl expression and induced the activation of microglia, then activated microglia released inflammatory factors via ERK signaling to cause pain. Our data might supply a novel molecular target for the therapy of CCI-induced neuropathic pain.

Endocytosis of the seven-transmembrane RGS1 protein activates G-protein-coupled signalling in Arabidopsis.

PubMed

Urano, Daisuke; Phan, Nguyen; Jones, Janice C; Yang, Jing; Huang, Jirong; Grigston, Jeffrey; Taylor, J Philip; Jones, Alan M

2012-10-01

Signal transduction typically begins by ligand-dependent activation of a concomitant partner that is otherwise in its resting state. However, in cases where signal activation is constitutive by default, the mechanism of regulation is unknown. The Arabidopsis thaliana heterotrimeric Gα protein self-activates without accessory proteins, and is kept in its resting state by the negative regulator, AtRGS1 (regulator of G-protein signalling 1), which is the prototype of a seven-transmembrane receptor fused with an RGS domain. Endocytosis of AtRGS1 by ligand-dependent endocytosis physically uncouples the GTPase-accelerating activity of AtRGS1 from the Gα protein, permitting sustained activation. Phosphorylation of AtRGS1 by AtWNK8 kinase causes AtRGS1 endocytosis, required for both G-protein-mediated sugar signalling and cell proliferation. In animals, receptor endocytosis results in signal desensitization, whereas in plants, endocytosis results in signal activation. These findings reveal how different organisms rearrange a regulatory system to result in opposite outcomes using similar phosphorylation-dependent endocytosis mechanisms.

Positive and negative regulation by SLP-76/ADAP and Pyk2 of chemokine-stimulated T-lymphocyte adhesion mediated by integrin α4β1

PubMed Central

Dios-Esponera, Ana; Isern de Val, Soledad; Sevilla-Movilla, Silvia; García-Verdugo, Rosa; García-Bernal, David; Arellano-Sánchez, Nohemí; Cabañas, Carlos; Teixidó, Joaquin

2015-01-01

Stimulation by chemokines of integrin α4β1–dependent T-lymphocyte adhesion is a crucial step for lymphocyte trafficking. The adaptor Vav1 is required for chemokine-activated T-cell adhesion mediated by α4β1. Conceivably, proteins associating with Vav1 could potentially modulate this adhesion. Correlating with activation by the chemokine CXCL12 of T-lymphocyte attachment to α4β1 ligands, a transient stimulation in the association of Vav1 with SLP-76, Pyk2, and ADAP was observed. Using T-cells depleted for SLP-76, ADAP, or Pyk2, or expressing Pyk2 kinase–inactive forms, we show that SLP-76 and ADAP stimulate chemokine-activated, α4β1-mediated adhesion, whereas Pyk2 opposes T-cell attachment. While CXCL12-promoted generation of high-affinity α4β1 is independent of SLP-76, ADAP, and Pyk2, the strength of α4β1-VCAM-1 interaction and cell spreading on VCAM-1 are targets of regulation by these three proteins. GTPase assays, expression of activated or dominant-negative Rac1, or combined ADAP and Pyk2 silencing indicated that Rac1 activation by CXCL12 is a common mediator response in SLP-76–, ADAP-, and Pyk2-regulated cell adhesion involving α4β1. Our data strongly suggest that chemokine-stimulated associations between Vav1, SLP-76, and ADAP facilitate Rac1 activation and α4β1-mediated adhesion, whereas Pyk2 opposes this adhesion by limiting Rac1 activation. PMID:26202465

Elevated β-catenin activity contributes to carboplatin resistance in A2780cp ovarian cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barghout, Samir H.; Zepeda, Nubia; Xu, Zhihua

Ovarian cancer is the fifth leading cause of cancer-related mortalities in women. Epithelial ovarian cancer (EOC) represents approximately 90% of all ovarian malignancies. Most EOC patients are diagnosed at advanced stages and current chemotherapy regimens are ineffective against advanced EOC due to the development of chemoresistance. It is important to better understand the molecular mechanisms underlying acquired resistance to effectively manage this disease. In this study, we examined the expression of the Wnt/β-catenin signaling components in the paired cisplatin-sensitive (A2780s) and cisplatin-resistant (A2780cp) EOC cell lines. Our results showed that several negative regulators of Wnt signaling are downregulated, whereas amore » few Wnt ligands and known Wnt/β-catenin target genes are upregulated in A2780cp cells compared to A2780s cells, suggesting that Wnt/β-catenin signaling is more active in A2780cp cells. Further analysis revealed nuclear localization of β-catenin and higher β-catenin transcriptional activity in A2780cp cells compared to A2780s cells. Finally, we demonstrated that chemical inhibition of β-catenin transcriptional activity by its inhibitor CCT036477 sensitized A2780cp cells to carboplatin, supporting a role for β-catenin in carboplatin resistance in A2780cp cells. In conclusion, our data suggest that increased Wnt/β-catenin signaling activity contributes to carboplatin resistance in A2780cp cells. - Highlights: • Wnt ligands and target genes are upregulated in cisplatin resistant A2780cp cells. • Negative regulators of Wnt signaling are down-regulated in A2780cp cells. • β-catenin transcriptional activity is higher in A2780cp cells compared to A2780s cells. • Inhibition of β-catenin activity increases carboplatin cytotoxicity in A2780cp cells.« less

Rho differentially regulates the Hippo pathway by modulating the interaction between Amot and Nf2 in the blastocyst.

PubMed

Shi, Xianle; Yin, Zixi; Ling, Bin; Wang, Lingling; Liu, Chang; Ruan, Xianhui; Zhang, Weiyu; Chen, Lingyi

2017-11-01

The Hippo pathway modulates the transcriptional activity of Yap to regulate the differentiation of the inner cell mass (ICM) and the trophectoderm (TE) in blastocysts. Yet how Hippo signaling is differentially regulated in ICM and TE cells is poorly understood. Through an inhibitor/activator screen, we have identified Rho as a negative regulator of Hippo in TE cells, and PKA as a positive regulator of Hippo in ICM cells. We further elucidated a novel mechanism by which Rho suppresses Hippo, distinct from the prevailing view that Rho inhibits Hippo signaling through modulating cytoskeleton remodeling and/or cell polarity. Active Rho prevents the phosphorylation of Amot Ser176, thus stabilizing the interaction between Amot and F-actin, and restricting the binding between Amot and Nf2. Moreover, Rho attenuates the interaction between Amot and Nf2 by binding to the coiled-coil domain of Amot. By blocking the association of Nf2 and Amot, Rho suppresses Hippo in TE cells. © 2017. Published by The Company of Biologists Ltd.

Tgf-beta induced Erk phosphorylation of smad linker region regulates smad signaling.

PubMed

Hough, Chris; Radu, Maria; Doré, Jules J E

2012-01-01

The Transforming Growth Factor-Beta (TGF-β) family is involved in regulating a variety of cellular processes such as apoptosis, differentiation, and proliferation. TGF-β binding to a Serine/Threonine kinase receptor complex causes the recruitment and subsequent activation of transcription factors known as smad2 and smad3. These proteins subsequently translocate into the nucleus to negatively or positively regulate gene expression. In this study, we define a second signaling pathway leading to TGF-β receptor activation of Extracellular Signal Regulated Kinase (Erk) in a cell-type dependent manner. TGF-β induced Erk activation was found in phenotypically normal mesenchymal cells, but not normal epithelial cells. By activating phosphotidylinositol 3-kinase (PI3K), TGF-β stimulates p21-activated kinase2 (Pak2) to phosphorylate c-Raf, ultimately resulting in Erk activation. Activation of Erk was necessary for TGF-β induced fibroblast replication. In addition, Erk phosphorylated the linker region of nuclear localized smads, resulting in increased half-life of C-terminal phospho-smad 2 and 3 and increased duration of smad target gene transcription. Together, these data show that in mesenchymal cell types the TGF-β/PI3K/Pak2/Raf/MEK/Erk pathway regulates smad signaling, is critical for TGF-β-induced growth and is part of an integrated signaling web containing multiple interacting pathways rather than discrete smad/non-smad pathways.

Age differences in emotion regulation effort: Pupil response distinguishes reappraisal and distraction for older but not younger adults.

PubMed

Martins, Bruna; Florjanczyk, Jan; Jackson, Nicholas J; Gatz, Margaret; Mather, Mara

2018-03-01

In previous research, older adults show greater emotional benefits from distracting themselves than from reappraising an event when strategically regulating emotion. Older adults also demonstrate an attentional preference to avoid, while younger adults show a bias toward approaching negative stimuli. This suggests a possible age-related differentiation of cognitive effort across approach and avoidance of negative stimuli during emotion regulation. In this study, we tracked cognitive effort via pupil dilation during the use of distraction (avoidance) and reappraisal (approach) strategies across age. Forty-eight younger adults (M = 20.94, SD = 1.78; 19 men) and 48 older adults (M = 68.82, SD = 5.40; 15 men) viewed a slideshow of negative images and were instructed to distract, reappraise, or passively view each image. Older adults showed greater pupil dilation during reappraisal than distraction, but younger adults displayed no difference between conditions-an effect that survived when controlling for gaze patterns. Gaze findings revealed that older adults looked less within images during active emotion regulation compared with passive viewing (no difference between distraction and reappraisal), and younger adults showed no difference across strategies. Younger adults gazed less within the most emotional image areas during distraction, but this did not significantly contribute to pupil response. Our findings support that distraction is less cognitively effortful than reinterpreting negative information in later life. These findings could be explained by older adults' motivational bias to disengage from negative information because of the age-related positivity effect, or compensation for decreased working memory resources across the life span. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The cAMP Response Element Binding protein (CREB) is activated by Insulin-like Growth Factor-1 (IGF-1) and regulates myostatin gene expression in skeletal myoblast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuloaga, R.; Fuentes, E.N.; Molina, A.

2013-10-18

Highlights: •IGF-1 induces the activation of CREB via IGF-1R/PI3K/PLC signaling pathway. •Calcium dependent signaling pathways regulate myostatin gene expression. •IGF-1 regulates myostatin gene expression via CREB transcription in skeletal myoblast. -- Abstract: Myostatin, a member of the Transforming Growth Factor beta (TGF-β) superfamily, plays an important role as a negative regulator of skeletal muscle growth and differentiation. We have previously reported that IGF-1 induces a transient myostatin mRNA expression, through the activation of the Nuclear Factor of Activated T cells (NFAT) in an IP{sub 3}/calcium-dependent manner. Here we examined the activation of CREB transcription factor as downstream targets of IGF-1more » during myoblast differentiation and its role as a regulator of myostatin gene expression. In cultured skeletal myoblast, IGF-1 induced the phosphorylation and transcriptional activation of CREB via IGF-1 Receptor/Phosphatidylinositol 3-Kinase (PI3K)/Phospholipase C gamma (PLC γ), signaling pathways. Also, IGF-1 induced calcium-dependent molecules such as Calmodulin Kinase II (CaMK II), Extracellular signal-regulated Kinases (ERK), Protein Kinase C (PKC). Additionally, we examined myostatin mRNA levels and myostatin promoter activity in differentiated myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents of myostatin and its reporter activity after treatment with IGF-1. The expression of myostatin in differentiated myoblast was downregulated by the transfection of siRNA–CREB and by pharmacological inhibitors of the signaling pathways involved in CREB activation. By using pharmacological and genetic approaches together these data demonstrate that IGF-1 regulates the myostatin gene expression via CREB transcription factor during muscle cell differentiation.« less

Suppression of Antigen-Specific T Cell Responses by the Kaposi's Sarcoma-Associated Herpesvirus Viral OX2 Protein and Its Cellular Orthologue, CD200

PubMed Central

Misstear, Karen; Chanas, Simon A.; Rezaee, S. A. Rahim; Colman, Rachel; Quinn, Laura L.; Long, Heather M.; Goodyear, Oliver; Lord, Janet M.; Hislop, Andrew D.

2012-01-01

Regulating appropriate activation of the immune response in the healthy host despite continual immune surveillance dictates that immune responses must be either self-limiting and therefore negatively regulated following their activation or prevented from developing inappropriately. In the case of antigen-specific T cells, their response is attenuated by several mechanisms, including ligation of CTLA-4 and PD-1. Through the study of the viral OX2 (vOX2) immunoregulator encoded by Kaposi's sarcoma-associated herpesvirus (KSHV), we have identified a T cell-attenuating role both for this protein and for CD200, a cellular orthologue of the viral vOX2 protein. In vitro, antigen-presenting cells (APC) expressing either native vOX2 or CD200 suppressed two functions of cognate antigen-specific T cell clones: gamma interferon (IFN-γ) production and mobilization of CD107a, a cytolytic granule component and measure of target cell killing ability. Mechanistically, vOX2 and CD200 expression on APC suppressed the phosphorylation of ERK1/2 mitogen-activated protein kinase in responding T cells. These data provide the first evidence for a role of both KSHV vOX2 and cellular CD200 in the negative regulation of antigen-specific T cell responses. They suggest that KSHV has evolved to harness the host CD200-based mechanism of attenuation of T cell responses to facilitate virus persistence and dissemination within the infected individual. Moreover, our studies define a new paradigm in immune modulation by viruses: the provision of a negative costimulatory signal to T cells by a virus-encoded orthologue of CD200. PMID:22491458

Human primitive brain displays negative mitochondrial-nuclear expression correlation of respiratory genes.

PubMed

Barshad, Gilad; Blumberg, Amit; Cohen, Tal; Mishmar, Dan

2018-06-14

Oxidative phosphorylation (OXPHOS), a fundamental energy source in all human tissues, requires interactions between mitochondrial (mtDNA)- and nuclear (nDNA)-encoded protein subunits. Although such interactions are fundamental to OXPHOS, bi-genomic coregulation is poorly understood. To address this question, we analyzed ∼8500 RNA-seq experiments from 48 human body sites. Despite well-known variation in mitochondrial activity, quantity, and morphology, we found overall positive mtDNA-nDNA OXPHOS genes' co-expression across human tissues. Nevertheless, negative mtDNA-nDNA gene expression correlation was identified in the hypothalamus, basal ganglia, and amygdala (subcortical brain regions, collectively termed the "primitive" brain). Single-cell RNA-seq analysis of mouse and human brains revealed that this phenomenon is evolutionarily conserved, and both are influenced by brain cell types (involving excitatory/inhibitory neurons and nonneuronal cells) and by their spatial brain location. As the "primitive" brain is highly oxidative, we hypothesized that such negative mtDNA-nDNA co-expression likely controls for the high mtDNA transcript levels, which enforce tight OXPHOS regulation, rather than rewiring toward glycolysis. Accordingly, we found "primitive" brain-specific up-regulation of lactate dehydrogenase B ( LDHB ), which associates with high OXPHOS activity, at the expense of LDHA , which promotes glycolysis. Analyses of co-expression, DNase-seq, and ChIP-seq experiments revealed candidate RNA-binding proteins and CEBPB as the best regulatory candidates to explain these phenomena. Finally, cross-tissue expression analysis unearthed tissue-dependent splice variants and OXPHOS subunit paralogs and allowed revising the list of canonical OXPHOS transcripts. Taken together, our analysis provides a comprehensive view of mito-nuclear gene co-expression across human tissues and provides overall insights into the bi-genomic regulation of mitochondrial activities. © 2018 Barshad et al.; Published by Cold Spring Harbor Laboratory Press.

CD14 Signaling Restrains Chronic Inflammation through Induction of p38-MAPK/SOCS-Dependent Tolerance

PubMed Central

Sahay, Bikash; Patsey, Rebeca L.; Eggers, Christian H.; Salazar, Juan C.; Radolf, Justin D.; Sellati, Timothy J.

2009-01-01

Current thinking emphasizes the primacy of CD14 in facilitating recognition of microbes by certain TLRs to initiate pro-inflammatory signaling events and the importance of p38-MAPK in augmenting such responses. Herein, this paradigm is challenged by demonstrating that recognition of live Borrelia burgdorferi not only triggers an inflammatory response in the absence of CD14, but one that is, in part, a consequence of altered PI3K/AKT/p38-MAPK signaling and impaired negative regulation of TLR2. CD14 deficiency results in increased localization of PI3K to lipid rafts, hyperphosphorylation of AKT, and reduced activation of p38. Such aberrant signaling leads to decreased negative regulation by SOCS1, SOCS3, and CIS, thereby compromising the induction of tolerance in macrophages and engendering more severe and persistent inflammatory responses to B. burgdorferi. Importantly, these altered signaling events and the higher cytokine production observed can be mimicked through shRNA and pharmacological inhibition of p38 activity in CD14-expressing macrophages. Perturbation of this CD14/p38-MAPK-dependent immune regulation may underlie development of infectious chronic inflammatory syndromes. PMID:20011115

Vascular endothelial growth factor-A enhances indoleamine 2,3-dioxygenase expression by dendritic cells and subsequently impacts lymphocyte proliferation

PubMed Central

Marti, Luciana Cavalheiro; Pavon, Lorena; Severino, Patricia; Sibov, Tatiana; Guilhen, Daiane; Moreira-Filho, Carlos Alberto

2013-01-01

Dendritic cells (DCs) are antigen (Ag)-presenting cells that activate and stimulate effective immune responses by T cells, but can also act as negative regulators of these responses and thus play important roles in immune regulation. Pro-angiogenic vascular endothelial growth factor (VEGF) has been shown to cause defective DC differentiation and maturation. Previous studies have demonstrated that the addition of VEGF to DC cultures renders these cells weak stimulators of Ag-specific T cells due to the inhibitory effects mediated by VEGF receptor 1 (VEGFR1) and/or VEGFR2 signalling. As the enzyme indoleamine 2,3-dioxygenase (IDO) is recognised as an important negative regulator of immune responses, this study aimed to investigate whether VEGF affects the expression of IDO by DCs and whether VEGF-matured DCs acquire a suppressor phenotype. Our results are the first to demonstrate that VEGF increases the expression and activity of IDO in DCs, which has a suppressive effect on Ag-specific and mitogen-stimulated lymphocyte proliferation. These mechanisms have broad implications for the study of immunological responses and tolerance under conditions as diverse as cancer, graft rejection and autoimmunity. PMID:24141959

Ursolic Acid Inhibits Leucine-Stimulated mTORC1 Signaling by Suppressing mTOR Localization to Lysosome

PubMed Central

Ou, Xiang; Liu, Meilian; Luo, Hairong; Dong, Lily Q.; Liu, Feng

2014-01-01

Ursolic acid (UA), a pentacyclic triterpenoid widely found in medicinal herbs and fruits, has been reported to possess a wide range of beneficial properties including anti-hyperglycemia, anti-obesity, and anti-cancer. However, the molecular mechanisms underlying the action of UA remain largely unknown. Here we show that UA inhibits leucine-induced activation of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway in C2C12 myotubes. The UA-mediated inhibition of mTORC1 is independent of Akt, tuberous sclerosis complex 1/2 (TSC1/2), and Ras homolog enriched in brain (Rheb), suggesting that UA negatively regulates mTORC1 signaling by targeting at a site downstream of these mTOR regulators. UA treatment had no effect on the interaction between mTOR and its activator Raptor or inhibitor Deptor, but suppressed the binding of RagB to Raptor and inhibited leucine-induced mTOR lysosomal localization. Taken together, our study identifies UA as a direct negative regulator of the mTORC1 signaling pathway and suggests a novel mechanism by which UA exerts its beneficial function. PMID:24740400

miR-218 is involved in the negative regulation of osteoclastogenesis and bone resorption by partial suppression of p38MAPK-c-Fos-NFATc1 signaling: Potential role for osteopenic diseases.

PubMed

Qu, Bo; Xia, Xun; Yan, Ming; Gong, Kai; Deng, Shaolin; Huang, Gang; Ma, Zehui; Pan, Xianming

2015-10-15

The increased osteoclastic activity accounts for pathological bone loss in diseases including osteoporosis. MicroRNAs are widely accepted to be involved in the regulation of osteopenic diseases. Recently, the low expression of miR-218 was demonstrated in CD14(+) peripheral blood mononuclear cells (PBMCs) from patients with postmenopausal osteoporosis. However, its role and the underlying mechanism in osteoporosis are still undefined. Here, an obvious decrease in miR-218 expression was observed during osteoclastogenesis under receptor activator of nuclear factor κB ligand (RANKL) stimulation, in both osteoclast precursors of bone marrow macrophages (BMMs) and RAW 264.7. Further analysis confirmed that overexpression of miR-218 obviously attenuated the formation of multinuclear mature osteoclasts, concomitant with the decrease in Trap and Cathepsin K levels, both the master regulators of osteoclastogenesis. Moreover, miR-218 up-regulation dramatically inhibited osteoclast precursor migration, actin ring formation and bone resorption. Mechanism assay demonstrated that miR-218 overexpression attenuated the expression of p38MAPK, c-Fos and NFATc1 signaling molecules. Following preconditioning with P79350, an agonist of p38MAPK, the inhibitor effect of miR-218 on osteoclastogenesis and bone-resorbing activity was strikingly ameliorated. Together, this study revealed a crucial role of miR-218 as a negative regulator for osteoclastogenesis and bone resorption by suppressing the p38MAPK-c-Fos-NFATc1 pathway. Accordingly, this research will provide a promising therapeutic agent against osteopenic diseases including osteoporosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Fission yeast Ccq1 is a modulator of telomerase activity

PubMed Central

Armstrong, Christine A; Moiseeva, Vera; Collopy, Laura C; Pearson, Siân R; Ullah, Tomalika R; Xi, Shidong T; Martin, Jennifer; Subramaniam, Shaan; Marelli, Sara; Amelina, Hanna

2018-01-01

Abstract Shelterin, the telomeric protein complex, plays a crucial role in telomere homeostasis. In fission yeast, telomerase is recruited to chromosome ends by the shelterin component Tpz1 and its binding partner Ccq1, where telomerase binds to the 3′ overhang to add telomeric repeats. Recruitment is initiated by the interaction of Ccq1 with the telomerase subunit Est1. However, how telomerase is released following elongation remains to be established. Here, we show that Ccq1 also has a role in the suppression of telomere elongation, when coupled with the Clr4 histone H3 methyl-transferase complex and the Clr3 histone deacetylase and nucleosome remodelling complex, SHREC. We have dissected the functions of Ccq1 by establishing a Ccq1-Est1 fusion system, which bypasses the telomerase recruitment step. We demonstrate that Ccq1 forms two distinct complexes for positive and negative telomerase regulation, with Est1 and Clr3 respectively. The negative form of Ccq1 promotes dissociation of Ccq1-telomerase from Tpz1, thereby restricting local telomerase activity. The Clr4 complex also has a negative regulation activity with Ccq1, independently of SHREC. Thus, we propose a model in which Ccq1-Est1 recruits telomerase to mediate telomere extension, whilst elongated telomeric DNA recruits Ccq1 with the chromatin-remodelling complexes, which in turn releases telomerase from the telomere. PMID:29216371

Phosphatase CD45 Both Positively and Negatively Regulates T Cell Receptor Phosphorylation in Reconstituted Membrane Protein Clusters*♦

PubMed Central

Furlan, Gabriela; Minowa, Takashi; Hanagata, Nobutaka; Kataoka-Hamai, Chiho; Kaizuka, Yoshihisa

2014-01-01

T cell receptor (TCR) phosphorylation requires the kinase Lck and phosphatase CD45. CD45 activates Lck by dephosphorylating an inhibitory tyrosine of Lck to relieve autoinhibition. However, CD45 also dephosphorylates the TCR, and the spatial exclusion of CD45 from TCR clustering in the plasma membrane appears to attenuate this negative effect of CD45. To further investigate the role of CD45 in signal initiation, we reconstituted membrane TCR clusters in vitro on supported lipid bilayers. Fluorescence microscopy of single clusters showed that incorporation of CD45 enhanced phosphorylation of TCR clusters, but only when Lck co-clustered with TCR. We found that clustered Lck autophosphorylated the inhibitory tyrosine and thus could be activated by CD45, whereas diffusive Lck molecules did not. In the TCR-Lck clusters and at low CD45 density, we speculate that the effect of Lck activation may overcome dephosphorylation of TCR, resulting in a net positive regulation. The CD45 density in physiological TCR clusters is also low because of the exclusion of CD45. Thus, we propose that the spatial organization of TCR/Lck/CD45 in T cell membranes is important not only for modulating the negative role of CD45 but also for creating conditions in which CD45 has a positive role in signal initiation. PMID:25128530

Cognitive and neural contributors to emotion regulation in aging

PubMed Central

Winecoff, Amy; LaBar, Kevin S.; Madden, David J.; Cabeza, Roberto

2011-01-01

Older adults, compared to younger adults, focus on emotional well-being. While the lifespan trajectory of emotional processing and its regulation has been characterized behaviorally, few studies have investigated the underlying neural mechanisms. Here, older adults (range: 59–73 years) and younger adults (range: 19–33 years) participated in a cognitive reappraisal task during functional magnetic resonance imaging (fMRI) scanning. On each trial, participants viewed positive, negative or neutral pictures and either naturally experienced the image (‘Experience’ condition) or attempted to detach themselves from the image (‘Reappraise’ condition). Across both age groups, cognitive reappraisal activated prefrontal regions similar to those reported in prior studies of emotion regulation, while emotional experience activated the bilateral amygdala. Psychophysiological interaction analyses revealed that the left inferior frontal gyrus (IFG) and amygdala demonstrated greater inverse connectivity during the ‘Reappraise’ condition relative to the ‘Experience’ condition. The only regions exhibiting significant age differences were the left IFG and the left superior temporal gyrus, for which greater regulation-related activation was observed in younger adults. Controlling for age, increased performance on measures of cognition predicted greater regulation-related decreases in amygdala activation. Thus, while older and younger adults use similar brain structures for emotion regulation and experience, the functional efficacy of those structures depends on underlying cognitive ability. PMID:20385663

Purified monomeric ligand.MD-2 complexes reveal molecular and structural requirements for activation and antagonism of TLR4 by Gram-negative bacterial endotoxins.

PubMed

Gioannini, Theresa L; Teghanemt, Athmane; Zhang, DeSheng; Esparza, Gregory; Yu, Liping; Weiss, Jerrold

2014-08-01

A major focus of work in our laboratory concerns the molecular mechanisms and structural bases of Gram-negative bacterial endotoxin recognition by host (e.g., human) endotoxin-recognition proteins that mediate and/or regulate activation of Toll-like receptor (TLR) 4. Here, we review studies of wild-type and variant monomeric endotoxin.MD-2 complexes first produced and characterized in our laboratories. These purified complexes have provided unique experimental reagents, revealing both quantitative and qualitative determinants of TLR4 activation and antagonism. This review is dedicated to the memory of Dr. Theresa L. Gioannini (1949-2014) who played a central role in many of the studies and discoveries that are reviewed.

Mycobacterium tuberculosis Maltosyltransferase GlgE, a Genetically Validated Antituberculosis Target, Is Negatively Regulated by Ser/Thr Phosphorylation*

PubMed Central

Leiba, Jade; Syson, Karl; Baronian, Grégory; Zanella-Cléon, Isabelle; Kalscheuer, Rainer; Kremer, Laurent; Bornemann, Stephen; Molle, Virginie

2013-01-01

GlgE is a maltosyltransferase involved in the biosynthesis of α-glucans that has been genetically validated as a potential therapeutic target against Mycobacterium tuberculosis. Despite also making α-glucan, the GlgC/GlgA glycogen pathway is distinct and allosterically regulated. We have used a combination of genetics and biochemistry to establish how the GlgE pathway is regulated. M. tuberculosis GlgE was phosphorylated specifically by the Ser/Thr protein kinase PknB in vitro on one serine and six threonine residues. Furthermore, GlgE was phosphorylated in vivo when expressed in Mycobacterium bovis bacillus Calmette–Guérin (BCG) but not when all seven phosphorylation sites were replaced by Ala residues. The GlgE orthologues from Mycobacterium smegmatis and Streptomyces coelicolor were phosphorylated by the corresponding PknB orthologues in vitro, implying that the phosphorylation of GlgE is widespread among actinomycetes. PknB-dependent phosphorylation of GlgE led to a 2 orders of magnitude reduction in catalytic efficiency in vitro. The activities of phosphoablative and phosphomimetic GlgE derivatives, where each phosphorylation site was substituted with either Ala or Asp residues, respectively, correlated with negative phosphoregulation. Complementation studies of a M. smegmatis glgE mutant strain with these GlgE derivatives, together with both classical and chemical forward genetics, were consistent with flux through the GlgE pathway being correlated with GlgE activity. We conclude that the GlgE pathway appears to be negatively regulated in actinomycetes through the phosphorylation of GlgE by PknB, a mechanism distinct from that known in the classical glycogen pathway. Thus, these findings open new opportunities to target the GlgE pathway therapeutically. PMID:23609448

Functional Analysis of SPINDLY in Gibberellin Signaling in Arabidopsis1[C][W][OA

PubMed Central

Silverstone, Aron L.; Tseng, Tong-Seung; Swain, Stephen M.; Dill, Alyssa; Jeong, Sun Yong; Olszewski, Neil E.; Sun, Tai-ping

2007-01-01

The Arabidopsis (Arabidopsis thaliana) SPINDLY (SPY) protein negatively regulates the gibberellin (GA) signaling pathway. SPY is an O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) with a protein-protein interaction domain consisting of 10 tetratricopeptide repeats (TPR). OGTs add a GlcNAc monosaccharide to serine/threonine residues of nuclear and cytosolic proteins. Determination of the molecular defects in 14 new spy alleles reveals that these mutations cluster in three TPRs and the C-terminal catalytic region. Phenotypic characterization of 12 spy alleles indicates that TPRs 6, 8, and 9 and the catalytic domain are crucial for GA-regulated stem elongation, floral induction, and fertility. TPRs 8 and 9 and the catalytic region are also important for modulating trichome morphology and inflorescence phyllotaxy. Consistent with a role for SPY in embryo development, several alleles affect seedling cotyledon number. These results suggest that three of the TPRs and the OGT activity in SPY are required for its function in GA signal transduction. We also examined the effect of spy mutations on another negative regulator of GA signaling, REPRESSOR OF ga1-3 (RGA). The DELLA motif in RGA is essential for GA-induced proteolysis of RGA, and deletion of this motif (as in rga-Δ17) causes a GA-insensitive dwarf phenotype. Here, we demonstrate that spy partially suppresses the rga-Δ17 phenotype but does not reduce rga-Δ17 or RGA protein levels or alter RGA nuclear localization. We propose that SPY may function as a negative regulator of GA response by increasing the activity of RGA, and presumably other DELLA proteins, by GlcNAc modification. PMID:17142481

Diabetes-induced hepatic pathogenic damage, inflammation, oxidative stress, and insulin resistance was exacerbated in zinc deficient mouse model.

PubMed

Zhang, Chi; Lu, Xuemian; Tan, Yi; Li, Bing; Miao, Xiao; Jin, Litai; Shi, Xue; Zhang, Xiang; Miao, Lining; Li, Xiaokun; Cai, Lu

2012-01-01

Zinc (Zn) deficiency often occurs in the patients with diabetes. Effects of Zn deficiency on diabetes-induced hepatic injury were investigated. Type 1 diabetes was induced in FVB mice with multiple low-dose streptozotocin. Hyperglycemic and age-matched control mice were treated with and without Zn chelator, N,N,N',N'-tetrakis (2-pyridylemethyl) ethylenediamine (TPEN), at 5 mg/kg body-weight daily for 4 months. Hepatic injury was examined by serum alanine aminotransferase (ALT) level and liver histopathological and biochemical changes. Hepatic Zn deficiency (lower than control level, p<0.05) was seen in the mice with either diabetes or TPEN treatment and more evident in the mice with both diabetes and TPEN. Zn deficiency exacerbated hepatic injuries, shown by further increased serum ALT, hepatic lipid accumulation, inflammation, oxidative damage, and endoplasmic reticulum stress-related cell death in Diabetes/TPEN group compared to Diabetes alone. Diabetes/TPEN group also showed a significant decrease in nuclear factor-erythroid 2-related factor 2 (Nrf2) expression and transcription action along with significant increases in Akt negative regulators, decrease in Akt and GSK-3β phosphorylation, and increase in nuclear accumulation of Fyn (a Nrf2 negative regulator). In vitro study with HepG2 cells showed that apoptotic effect of TPEN at 0.5-1.0 µM could be completely prevented by simultaneous Zn supplementation at the dose range of 30-50 µM. Zn is required for maintaining Akt activation by inhibiting the expression of Akt negative regulators; Akt activation can inhibit Fyn nuclear translocation to export nuclear Nrf2 to cytoplasm for degradation. Zn deficiency significantly enhanced diabetes-induced hepatic injury likely through down-regulation of Nrf2 function.

Interferon Regulatory Factor 7 Functions as a Novel Negative Regulator of Pathological Cardiac Hypertrophy

PubMed Central

Jiang, Ding-Sheng; Liu, Yu; Zhou, Heng; Zhang, Yan; Zhang, Xiao-Dong; Zhang, Xiao-Fei; Chen, Ke; Gao, Lu; Peng, Juan; Gong, Hui; Chen, Yingjie; Yang, Qinglin; Liu, Peter P.; Fan, Guo-Chang; Zou, Yunzeng; Li, Hongliang

2017-01-01

Cardiac hypertrophy is a complex pathological process that involves multiple factors including inflammation and apoptosis. Interferon regulatory factor 7 (IRF7) is a multifunctional regulator that participates in immune regulation, cell differentiation, apoptosis, and oncogenesis. However, the role of IRF7 in cardiac hypertrophy remains unclear. We performed aortic banding in cardiac-specific IRF7 transgenic mice, IRF7 knockout mice, and the wild-type littermates of these mice. Our results demonstrated that IRF7 was downregulated in aortic banding–induced animal hearts and cardiomyocytes that had been treated with angiotensin II or phenylephrine for 48 hours. Accordingly, heart-specific overexpression of IRF7 significantly attenuated pressure overload–induced cardiac hypertrophy, fibrosis, and dysfunction, whereas loss of IRF7 led to opposite effects. Moreover, IRF7 protected against angiotensin II–induced cardiomyocyte hypertrophy in vitro. Mechanistically, we identified that IRF7-dependent cardioprotection was mediated through IRF7 binding to inhibitor of κB kinase-β, and subsequent nuclear factor-κB inactivation. In fact, blocking nuclear factor-κB signaling with cardiac-specific inhibitors of κBαS32A/S36A super-repressor transgene counteracted the adverse effect of IRF7 deficiency. Conversely, activation of nuclear factor-κB signaling via a cardiac-specific conditional inhibitor of κB kinase-βS177E/S181E (constitutively active) transgene negated the antihypertrophic effect of IRF7 overexpression. Our data demonstrate that IRF7 acts as a novel negative regulator of pathological cardiac hypertrophy by inhibiting nuclear factor-κB signaling and may constitute a potential therapeutic target for pathological cardiac hypertrophy. PMID:24396025

ULTRAPETALA1 encodes a SAND domain putative transcriptional regulator that controls shoot and floral meristem activity in Arabidopsis.

PubMed

Carles, Cristel C; Choffnes-Inada, Dan; Reville, Keira; Lertpiriyapong, Kvin; Fletcher, Jennifer C

2005-03-01

The higher-plant shoot apical meristem is a dynamic structure continuously producing cells that become incorporated into new leaves, stems and flowers. The maintenance of a constant flow of cells through the meristem depends on coordination of two antagonistic processes: self-renewal of the stem cell population and initiation of the lateral organs. This coordination is stringently controlled by gene networks that contain both positive and negative components. We have previously defined the ULTRAPETALA1 (ULT1) gene as a key negative regulator of cell accumulation in Arabidopsis shoot and floral meristems, because mutations in ULT1 cause the enlargement of inflorescence and floral meristems, the production of supernumerary flowers and floral organs, and a delay in floral meristem termination. Here, we show that ULT1 negatively regulates the size of the WUSCHEL (WUS)-expressing organizing center in inflorescence meristems. We have cloned the ULT1 gene and find that it encodes a small protein containing a B-box-like motif and a SAND domain, a DNA-binding motif previously reported only in animal transcription factors. ULT1 and its Arabidopsis paralog ULT2 define a novel small gene family in plants. ULT1 and ULT2 are expressed coordinately in embryonic shoot apical meristems, in inflorescence and floral meristems, and in developing stamens, carpels and ovules. Additionally, ULT1 is expressed in vegetative meristems and leaf primordia. ULT2 protein can compensate for mutant ULT1 protein when overexpressed in an ult1 background, indicating that the two genes may regulate a common set of targets during plant development. Downregulation of both ULT genes can lead to shoot apical meristem arrest shortly after germination, revealing a requirement for ULT activity in early development.

Mycobacterium tuberculosis maltosyltransferase GlgE, a genetically validated antituberculosis target, is negatively regulated by Ser/Thr phosphorylation.

PubMed

Leiba, Jade; Syson, Karl; Baronian, Grégory; Zanella-Cléon, Isabelle; Kalscheuer, Rainer; Kremer, Laurent; Bornemann, Stephen; Molle, Virginie

2013-06-07

GlgE is a maltosyltransferase involved in the biosynthesis of α-glucans that has been genetically validated as a potential therapeutic target against Mycobacterium tuberculosis. Despite also making α-glucan, the GlgC/GlgA glycogen pathway is distinct and allosterically regulated. We have used a combination of genetics and biochemistry to establish how the GlgE pathway is regulated. M. tuberculosis GlgE was phosphorylated specifically by the Ser/Thr protein kinase PknB in vitro on one serine and six threonine residues. Furthermore, GlgE was phosphorylated in vivo when expressed in Mycobacterium bovis bacillus Calmette-Guérin (BCG) but not when all seven phosphorylation sites were replaced by Ala residues. The GlgE orthologues from Mycobacterium smegmatis and Streptomyces coelicolor were phosphorylated by the corresponding PknB orthologues in vitro, implying that the phosphorylation of GlgE is widespread among actinomycetes. PknB-dependent phosphorylation of GlgE led to a 2 orders of magnitude reduction in catalytic efficiency in vitro. The activities of phosphoablative and phosphomimetic GlgE derivatives, where each phosphorylation site was substituted with either Ala or Asp residues, respectively, correlated with negative phosphoregulation. Complementation studies of a M. smegmatis glgE mutant strain with these GlgE derivatives, together with both classical and chemical forward genetics, were consistent with flux through the GlgE pathway being correlated with GlgE activity. We conclude that the GlgE pathway appears to be negatively regulated in actinomycetes through the phosphorylation of GlgE by PknB, a mechanism distinct from that known in the classical glycogen pathway. Thus, these findings open new opportunities to target the GlgE pathway therapeutically.

Negative Regulation of Violacein Biosynthesis in Chromobacterium violaceum

PubMed Central

Devescovi, Giulia; Kojic, Milan; Covaceuszach, Sonia; Cámara, Miguel; Williams, Paul; Bertani, Iris; Subramoni, Sujatha; Venturi, Vittorio

2017-01-01

In Chromobacteium violaceum, the purple pigment violacein is under positive regulation by the N-acylhomoserine lactone CviI/R quorum sensing system and negative regulation by an uncharacterized putative repressor. In this study we report that the biosynthesis of violacein is negatively controlled by a novel repressor protein, VioS. The violacein operon is regulated negatively by VioS and positively by the CviI/R system in both C. violaceum and in a heterologous Escherichia coli genetic background. VioS does not regulate the CviI/R system and apart from violacein, VioS, and quorum sensing regulate other phenotypes antagonistically. Quorum sensing regulated phenotypes in C. violaceum are therefore further regulated providing an additional level of control. PMID:28326068

Coordinated balancing of muscle oxidative metabolism through PGC-1{alpha} increases metabolic flexibility and preserves insulin sensitivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Summermatter, Serge; Troxler, Heinz; Santos, Gesa

2011-04-29

Highlights: {yields} PGC-1{alpha} enhances muscle oxidative capacity. {yields} PGC-1{alpha} promotes concomitantly positive and negative regulators of lipid oxidation. {yields} Regulator abundance enhances metabolic flexibility and balances oxidative metabolism. {yields} Balanced oxidation prevents detrimental acylcarnitine and ROS generation. {yields} Absence of detrimental metabolites preserves insulin sensitivity -- Abstract: The peroxisome proliferator-activated receptor {gamma} coactivator 1{alpha} (PGC-1{alpha}) enhances oxidative metabolism in skeletal muscle. Excessive lipid oxidation and electron transport chain activity can, however, lead to the accumulation of harmful metabolites and impair glucose homeostasis. Here, we investigated the effect of over-expression of PGC-1{alpha} on metabolic control and generation of insulin desensitizing agentsmore » in extensor digitorum longus (EDL), a muscle that exhibits low levels of PGC-1{alpha} in the untrained state and minimally relies on oxidative metabolism. We demonstrate that PGC-1{alpha} induces a strictly balanced substrate oxidation in EDL by concomitantly promoting the transcription of activators and inhibitors of lipid oxidation. Moreover, we show that PGC-1{alpha} enhances the potential to uncouple oxidative phosphorylation. Thereby, PGC-1{alpha} boosts elevated, yet tightly regulated oxidative metabolism devoid of side products that are detrimental for glucose homeostasis. Accordingly, PI3K activity, an early phase marker for insulin resistance, is preserved in EDL muscle. Our findings suggest that PGC-1{alpha} coordinately coactivates the simultaneous transcription of gene clusters implicated in the positive and negative regulation of oxidative metabolism and thereby increases metabolic flexibility. Thus, in mice fed a normal chow diet, over-expression of PGC-1{alpha} does not alter insulin sensitivity and the metabolic adaptations elicited by PGC-1{alpha} mimic the beneficial effects of endurance training on muscle metabolism in this context.« less

Gonadotropin-Releasing Hormone Pulse Sensitivity of Follicle-Stimulating Hormone-β Gene Is Mediated by Differential Expression of Positive Regulatory Activator Protein 1 Factors and Corepressors SKIL and TGIF1

PubMed Central

Mistry, Devendra S.; Tsutsumi, Rie; Fernandez, Marina; Sharma, Shweta; Cardenas, Steven A.; Lawson, Mark A.

2011-01-01

Gonadotropin synthesis and release is dependent on pulsatile stimulation by the hypothalamic neuropeptide GnRH. Generally, slow GnRH pulses promote FSH production, whereas rapid pulses favor LH, but the molecular mechanism underlying this pulse sensitivity is poorly understood. In this study, we developed and tested a model for FSHβ regulation in mouse LβT2 gonadotropes. By mining a previous microarray data set, we found that mRNA for positive regulators of Fshb expression, such as Fos and Jun, were up-regulated at slower pulse frequencies than a number of potential negative regulators, such as the corepressors Skil, Crem, and Tgif1. These latter corepressors reduced Fshb promoter activity whether driven by transfection of individual transcription factors or by treatment with GnRH and activin. Overexpression of binding or phosphorylation-defective ski-oncogene-like protein (SKIL) and TG interacting factor (TGIF1) mutants, however, failed to repress Fshb promoter activity. Knockdown of the endogenous repressors SKIL and TGIF1, but not cAMP response element-modulator, increased Fshb promoter activity driven by constant GnRH or activin. Chromatin immunoprecipitation analysis showed that FOS, SKIL, and TGIF1 occupy the FSHβ promoter in a cyclical manner after GnRH stimulation. Overexpression of corepressors SKIL or TGIF1 repressed induction of the Fshb promoter at the slow GnRH pulse frequency but had little effect at the fast pulse frequency. In contrast, knockdown of endogenous SKIL or TGIF1 selectively increased Fshb mRNA at the fast GnRH pulse frequency. Therefore, we propose a potential mechanism by which production of gonadotropin Fshb is modulated by positive transcription factors and negative corepressors with different pulse sensitivities. PMID:21659477

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byun, Eui-Baek; Choi, Han-Gyu; Sung, Nak-Yun

Highlights: Black-Right-Pointing-Pointer Expressions of CD80, CD86, and MHC class I/II were inhibited by EGCG via 67LR. Black-Right-Pointing-Pointer EGCG-treated DCs inhibited LPS-induced pro-inflammatory cytokines via 67LR. Black-Right-Pointing-Pointer EGCG-treated DCs inhibited MAPKs activation and NF-{kappa}B p65 translocation via 67LR. Black-Right-Pointing-Pointer EGCG elevated the expression of the Tollip protein through 67LR in DCs. -- Abstract: Epigallocatechin-3-gallate (EGCG), a major active polyphenol of green tea, has been shown to down-regulate inflammatory responses in dendritic cells (DCs); however, the underlying mechanism has not been understood. Recently, we identified the 67-kDa laminin receptor (67LR) as a cell-surface EGCG receptor. In this study, we showed the molecularmore » basis for the down-regulation of toll-like receptor 4 (TLR4) signal transduction by EGCG in DCs. The expressions of CD80, CD86, and MHC class I and II, which are molecules essential for antigen presentation by DCs, were inhibited by EGCG via 67LR. In addition, EGCG-treated DCs inhibited lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines (tumor necrosis factor [TNF]-{alpha}, interleukin [IL]-1{beta}, and IL-6) and activation of mitogen-activated protein kinases (MAPKs), e.g., extracellular signal-regulated kinase 1/2 (ERK1/2), p38, c-Jun N-terminal kinase (JNK), and nuclear factor {kappa}B (NF-{kappa}B) p65 translocation through 67LR. Interestingly, we also found that EGCG markedly elevated the expression of the Tollip protein, a negative regulator of TLR signaling, through 67LR. These novel findings provide new insight into the understanding of negative regulatory mechanisms of the TLR4 signaling pathway and consequent inflammatory responses that are implicated in the development and progression of many chronic diseases.« less

Shp1 regulates T cell homeostasis by limiting IL-4 signals

PubMed Central

Johnson, Dylan J.; Pao, Lily I.; Dhanji, Salim; Murakami, Kiichi

2013-01-01

The protein-tyrosine phosphatase Shp1 is expressed ubiquitously in hematopoietic cells and is generally viewed as a negative regulatory molecule. Mutations in Ptpn6, which encodes Shp1, result in widespread inflammation and premature death, known as the motheaten (me) phenotype. Previous studies identified Shp1 as a negative regulator of TCR signaling, but the severe systemic inflammation in me mice may have confounded our understanding of Shp1 function in T cell biology. To define the T cell–intrinsic role of Shp1, we characterized mice with a T cell–specific Shp1 deletion (Shp1fl/fl CD4-cre). Surprisingly, thymocyte selection and peripheral TCR sensitivity were unaltered in the absence of Shp1. Instead, Shp1fl/fl CD4-cre mice had increased frequencies of memory phenotype T cells that expressed elevated levels of CD44. Activation of Shp1-deficient CD4+ T cells also resulted in skewing to the Th2 lineage and increased IL-4 production. After IL-4 stimulation of Shp1-deficient T cells, Stat 6 activation was sustained, leading to enhanced Th2 skewing. Accordingly, we observed elevated serum IgE in the steady state. Blocking or genetic deletion of IL-4 in the absence of Shp1 resulted in a marked reduction of the CD44hi population. Therefore, Shp1 is an essential negative regulator of IL-4 signaling in T lymphocytes. PMID:23797092

Optimism, Positive and Negative Affect, and Goal Adjustment Strategies: Their Relationship to Activity Patterns in Patients with Chronic Musculoskeletal Pain.

PubMed

Esteve, Rosa; López-Martínez, Alicia E; Peters, Madelon L; Serrano-Ibáñez, Elena R; Ruiz-Párraga, Gema T; Ramírez-Maestre, Carmen

2018-01-01

Activity patterns are the product of pain and of the self-regulation of current goals in the context of pain. The aim of this study was to investigate the association between goal management strategies and activity patterns while taking into account the role of optimism/pessimism and positive/negative affect. Two hundred and thirty-seven patients with chronic musculoskeletal pain filled out questionnaires on optimism, positive and negative affect, pain intensity, and the activity patterns they employed in dealing with their pain. Questionnaires were also administered to assess their general goal management strategies: goal persistence, flexible goal adjustment, and disengagement and reengagement with goals. Structural equation modelling showed that higher levels of optimism were related to persistence, flexible goal management, and commitment to new goals. These strategies were associated with higher positive affect, persistence in finishing tasks despite pain, and infrequent avoidance behaviour in the presence or anticipation of pain. The strategies used by the patients with chronic musculoskeletal pain to manage their life goals are related to their activity patterns.

Shigella flexneri type III secreted effector OspF reveals new crosstalks of proinflammatory signaling pathways during bacterial infection.

PubMed

Reiterer, Veronika; Grossniklaus, Lars; Tschon, Therese; Kasper, Christoph Alexander; Sorg, Isabel; Arrieumerlou, Cécile

2011-07-01

Shigella flexneri type III secreted effector OspF harbors a phosphothreonine lyase activity that irreversibly dephosphorylates MAP kinases (MAPKs) p38 and ERK in infected epithelial cells and thereby, dampens innate immunity. Whereas this activity has been well characterized, the impact of OspF on other host signaling pathways that control inflammation was unknown. Here we report that OspF potentiates the activation of the MAPK JNK and the transcription factor NF-κB during S. flexneri infection. This unexpected effect of OspF was dependent on the phosphothreonine lyase activity of OspF on p38, and resulted from the disruption of a negative feedback loop regulation between p38 and TGF-beta activated kinase 1 (TAK1), mediated via the phosphorylation of TAK1-binding protein 1. Interestingly, potentiated JNK activation was not associated with enhanced c-Jun signaling as OspF also inhibits c-Jun expression at the transcriptional level. Altogether, our data reveal the impact of OspF on the activation of NF-κB, JNK and c-Jun, and demonstrate the existence of a negative feedback loop regulation between p38 and TAK1 during S. flexneri infection. Furthermore, this study validates the use of bacterial effectors as molecular tools to identify the crosstalks that connect important host signaling pathways induced upon bacterial infection. Copyright © 2011 Elsevier Inc. All rights reserved.

PKCalpha-mediated ERK, JNK and p38 activation regulates the myogenic program in human rhabdomyosarcoma cells.

PubMed

Mauro, Annunziata; Ciccarelli, Carmela; De Cesaris, Paola; Scoglio, Arianna; Bouché, Marina; Molinaro, Mario; Aquino, Angelo; Zani, Bianca Maria

2002-09-15

We have previously suggested that PKCalpha has a role in 12-O-Tetradecanoylphorbol-13-acetate (TPA)-mediated growth arrest and myogenic differentiation in human embryonal rhabdomyosarcoma cells (RD). Here, by monitoring the signalling pathways triggered by TPA, we demonstrate that PKCalpha mediates these effects by inducing transient activation of c-Jun N-terminal protein kinases (JNKs) and sustained activation of both p38 kinase and extracellular signal-regulated kinases (ERKs) (all referred to as MAPKs). Activation of MAPKs following ectopic expression of constitutively active PKCalpha, but not its dominant-negative form, is also demonstrated. We investigated the selective contribution of MAPKs to growth arrest and myogenic differentiation by monitoring the activation of MAPK pathways, as well as by dissecting MAPK pathways using MEK1/2 inhibitor (UO126), p38 inhibitor (SB203580) and JNK and p38 agonist (anisomycin) treatments. Growth-arresting signals are triggered either by transient and sustained JNK activation (by TPA and anisomycin, respectively) or by preventing both ERK and JNK activation (UO126) and are maintained, rather than induced, by p38. We therefore suggest a key role for JNK in controlling ERK-mediated mitogenic activity. Notably, sarcomeric myosin expression is induced by both TPA and UO126 but is abrogated by the p38 inhibitor. This finding indicates a pivotal role for p38 in controlling the myogenic program. Anisomycin persistently activates p38 and JNKs but prevents myosin expression induced by TPA. In accordance with this negative role, reactivation of JNKs by anisomycin, in UO126-pre-treated cells, also prevents myosin expression. This indicates that, unlike the transient JNK activation that occurs in the TPA-mediated myogenic process, long-lasting JNK activation supports the growth-arrest state but antagonises p38-mediated myosin expression. Lastly, our results with the MEK inhibitor suggest a key role of the ERK pathway in regulating myogenic-related morphology in differentiated RD cells.

Environmental signals modulate ToxT-dependent virulence factor expression in Vibrio cholerae.

PubMed

Schuhmacher, D A; Klose, K E

1999-03-01

The regulatory protein ToxT directly activates the transcription of virulence factors in Vibrio cholerae, including cholera toxin (CT) and the toxin-coregulated pilus (TCP). Specific environmental signals stimulate virulence factor expression by inducing the transcription of toxT. We demonstrate that transcriptional activation by the ToxT protein is also modulated by environmental signals. ToxT expressed from an inducible promoter activated high-level expression of CT and TCP in V. cholerae at 30 degrees C, but expression of CT and TCP was significantly decreased or abolished by the addition of 0.4% bile to the medium and/or an increase of the temperature to 37 degrees C. Also, expression of six ToxT-dependent TnphoA fusions was modulated by temperature and bile. Measurement of ToxT-dependent transcription of genes encoding CT and TCP by ctxAp- and tcpAp-luciferase fusions confirmed that negative regulation by 37 degrees C or bile occurs at the transcriptional level in V. cholerae. Interestingly, ToxT-dependent transcription of these same promoters in Salmonella typhimurium was relatively insensitive to regulation by temperature or bile. These data are consistent with ToxT transcriptional activity being modulated by environmental signals in V. cholerae and demonstrate an additional level of complexity governing the expression of virulence factors in this pathogen. We propose that negative regulation of ToxT-dependent transcription by environmental signals prevents the incorrect temporal and spatial expression of virulence factors during cholera pathogenesis.

Protein Kinase Cδ Promotes Transitional B Cell-Negative Selection and Limits Proximal B Cell Receptor Signaling To Enforce Tolerance

PubMed Central

Zikherman, Julie; Lau, Tannia; Leitges, Michael; Weiss, Arthur

2014-01-01

Protein kinase Cδ (PKCδ) deficiency causes autoimmune pathology in humans and mice and is crucial for the maintenance of B cell homeostasis. However, the mechanisms underlying autoimmune disease in PKCδ deficiency remain poorly defined. Here, we address the antigen-dependent and -independent roles of PKCδ in B cell development, repertoire selection, and antigen responsiveness. We demonstrate that PKCδ is rapidly phosphorylated downstream of both the B cell receptor (BCR) and the B cell-activating factor (BAFF) receptor. We found that PKCδ is essential for antigen-dependent negative selection of splenic transitional B cells and is required for activation of the proapoptotic Ca2+-Erk pathway that is selectively activated during B cell-negative selection. Unexpectedly, we also identified a previously unrecognized role for PKCδ as a proximal negative regulator of BCR signaling that substantially impacts survival and proliferation of mature follicular B cells. As a consequence of these distinct roles, PKCδ deficiency leads to the survival and development of a B cell repertoire that is not only aberrantly autoreactive but also hyperresponsive to antigen stimulation. PMID:24515435

MYC2 Differentially Modulates Diverse Jasmonate-Dependent Functions in Arabidopsis[W

PubMed Central

Dombrecht, Bruno; Xue, Gang Ping; Sprague, Susan J.; Kirkegaard, John A.; Ross, John J.; Reid, James B.; Fitt, Gary P.; Sewelam, Nasser; Schenk, Peer M.; Manners, John M.; Kazan, Kemal

2007-01-01

The Arabidopsis thaliana basic helix-loop-helix Leu zipper transcription factor (TF) MYC2/JIN1 differentially regulates jasmonate (JA)-responsive pathogen defense (e.g., PDF1.2) and wound response (e.g., VSP) genes. In this study, genome-wide transcriptional profiling of wild type and mutant myc2/jin1 plants followed by functional analyses has revealed new roles for MYC2 in the modulation of diverse JA functions. We found that MYC2 negatively regulates Trp and Trp-derived secondary metabolism such as indole glucosinolate biosynthesis during JA signaling. Furthermore, MYC2 positively regulates JA-mediated resistance to insect pests, such as Helicoverpa armigera, and tolerance to oxidative stress, possibly via enhanced ascorbate redox cycling and flavonoid biosynthesis. Analyses of MYC2 cis binding elements and expression of MYC2-regulated genes in T-DNA insertion lines of a subset of MYC2–regulated TFs suggested that MYC2 might modulate JA responses via differential regulation of an intermediate spectrum of TFs with activating or repressing roles in JA signaling. MYC2 also negatively regulates its own expression, and this may be one of the mechanisms used in fine-tuning JA signaling. Overall, these results provide new insights into the function of MYC2 and the transcriptional coordination of the JA signaling pathway. PMID:17616737