Enhancing Parental Well-being: Initial Efficacy of a 21-Day Online Self-help Mindfulness-Based Intervention for Parents.

Objectives: Parental self-care is extremely important in the face of stress throughout parenthood. A 21-day online mindfulness-based intervention was developed that was aimed at enhancing parental well-being. The present study evaluated this intervention by examining its initial efficacy on parents' mindfulness, parenting stress, subjective well-being, and symptoms of depression and anxiety. Methods: Participants were 273 parents (90.11% mothers) who were randomly assigned to the 21-day mindfulness-based intervention group (n = 136) or waitlist control group (n = 137). Pre-intervention assessment, immediate post-intervention assessment, and 30-day follow-up assessment were conducted to assess parents' mindfulness, parenting stress, subjective well-being, and symptoms of depression and anxiety. Results: Linear mixed models indicated that the group × time effects on subjective well-being, anxiety symptoms, and mindfulness were significant, after controlling for sex, age, education, income, habit of mindfulness practice, hours of weekly mindfulness practice, and diagnostic history of psychiatric disorder. Follow-up analyses indicated that compared to baseline, participants from the intervention group reported significantly greater subjective well-being and mindfulness, and fewer symptoms of anxiety than did those from the waitlist control group. The group × time effects on parenting stress and depressive symptoms were non-significant. Exploratory findings further suggested practicality and perceived acceptability of the intervention. Conclusions: This study showed initial efficacy of a 21-day online mindfulness-based intervention on parents' subjective well-being, anxiety symptoms, and mindfulness. The findings inform researchers and practitioners about the utility of a brief mindfulness-based intervention in promotion parental well-being. Other areas of feasibility warrant future investigation.

Anti-Inflammatory Effects of a Cordyceps sinensis Mycelium Culture Extract (Cs-4) on Rodent Models of Allergic Rhinitis and Asthma.

Allergic rhinitis and asthma are common chronic allergic diseases of the respiratory tract, which are accompanied by immunoglobulin E (IgE)-mediated inflammation and the involvement of type 2 T helper cells, mast cells, and eosinophils. Cordyceps sinensis (Berk.) Sacc is a fungal parasite on the larva of Lepidoptera. It has been considered to be a health-promoting food and, also, one of the best-known herbal remedies for the treatment of airway diseases, such as asthma and lung inflammation. In the present study, we demonstrated the antiallergic rhinitis effect of Cs-4, a water extract prepared from the mycelium culture of Cordyceps sinensis (Berk) Sacc, on ovalbumin (OVA)-induced allergic rhinitis in mice and the anti-asthmatic effect of Cs-4 in a rat model of asthma. Treatment with Cs-4 suppressed the nasal symptoms induced in OVA-sensitized and challenged mice. The inhibition was associated with a reduction in IgE/OVA-IgE and interleukin (IL)-4/IL-13 levels in the nasal fluid. Cs-4 treatment also decreased airway responsiveness and ameliorated the scratching behavior in capsaicin-challenged rats. It also reduced plasma IgE levels, as well as IgE and eosinophil peroxidase levels, in the bronchoalveolar fluid. Cs-4 treatment completely suppressed the increases in IL-4, IL-5, and IL-13 levels in rat lung tissue. In conclusion, our results suggest that Cs-4 has the potential to alleviate immune hypersensitivity reactions in allergic rhinitis and asthma.

48Biochemical mechanisms of the anti-obesity effect of a triterpenoid-enriched extract of Cynomorium songaricum in mice with high-fat-diet-induced obesity.

BACKGROUND: HCY2, a triterpenoid-enriched extract of Cynomorii Herba, has been shown to reduce body weight and adiposity and attenuate manifestations of the associated metabolic syndrome in high-fat-diet (HFD)-fed mice. PURPOSE: The current study aimed to investigate the biochemical mechanism underlying the anti-obesity effect produced by HCY2. STUDY DESIGN: An HCY2-containing extract was examined for its effects on the regulation of adenosine monophosphate-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor gamma co-activator-1 (PGC1) pathways and the protein expression related to mitochondrial uncoupling and biogenesis in skeletal muscle using an HFD-induced obese mouse model. METHODS: The obese mouse model was produced by providing HFD (60% kcal from fat) ad libitum. The effects and signaling mechanisms of HCY2 were examined using analytical procedures which included enzyme-linked immunosorbent assay kits, Western blot analysis, and the use of a Clark-type oxygen electrode. RESULTS: The current study revealed that the weight reduction produced by HCY2 is associated with the activation of the AMPK signaling pathway, with resultant increases in mitochondrial biogenesis and expression of uncoupling protein 3 in skeletal muscle in vivo. The use of a recoupler, ketocholestanol, delineated the precise role of mitochondrial uncoupling in the anti-obesity effect afforded by HCY2 in obese mice. CONCLUSION: Our experimental findings offer a promising prospect for the use of HCY2 in the management of obesity through the regulation of AMPK/PGC1 pathways.

A Chinese Herbal Formulation, Xiao-Er-An-Shen Decoction, Attenuates Tourette Syndrome, Possibly by Reversing Abnormal Changes in Neurotransmitter Levels and Enhancing Antioxidant Status in Mouse Brain.

Xiao-Er-An-Shen Decoction (XEASD) has been used clinically for the treatment of Tourette syndrome (TS) in children for more than 20 years in mainland China. The biochemical mechanism underlying the therapeutic action produced by XEASD treatment against TS remains unknown. However, a previous study has shown that pre-incubation of PC12 neuronal cells with XEASD can induce neurite outgrowth and protect against oxidative stress. In the present study, using a mouse model of TS induced by 3,3'-iminodipropionitrile (IDPN), stereotypy scoring, and locomotor activity were assessed. Levels of neurotransmitters including glutamate, aspartate, and gamma-aminobutyric acid (GABA) in brain tissue as well as plasma cyclic adenosine monophosphate (cAMP) were measured using assay kits. The ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) and Mn-superoxide dismutase (MnSOD) activity in brain mitochondrial fractions as well as mitochondrial glutathione reductase and cytosolic γ-glutamylcysteine activities were also examined. The phosphorylation of cAMP-responsive element binding protein (CREB) in brain tissue was measured by Western blot analysis. XEASD treatment was found to significantly ameliorate the severity of behavioral symptoms in affected mice, as evidenced by decreases in the stereotypy score and locomotor activity. The beneficial effect of XEASD was accompanied by the reversal of abnormal levels of GABA, glutamate, and aspartate, in brain tissue of IDPN-challenged mice. In addition, XEASD treatment increased plasma cyclic adenosine monophosphate (cAMP) levels and activated the phosphorylation of CREB in brain tissue of TS mice. Furthermore, XEASD treatment was found to enhance the antioxidant status of brain tissue in affected mice, as evidenced by increases in the GSH/GSSG ratio and the activity of MnSOD in brain mitochondrial fractions. Taken together, these experimental results will hopefully provide insight into the pharmacological basis for the beneficial effects of XEASD in children suffering from TS.

Changes in Stigma Experience Among Mental Health Service Users over Time: A Qualitative Study with Focus Groups.

Public expenditure on mental health education has grown exponentially in the past two decades. A qualitative study using focus groups was used to explore whether the experience of stigma among 22 mental health service users improved over time. We identified five major themes on changes in social stigma, perceived stigma, and stigma coping. Stigmatizing and discriminatory experiences were still common in workplace, healthcare system, and relational aspects but some participants perceived that there were reductions in social stigma. Participants believed that media portrayal and celebrity effect were important in fostering greater acceptance toward people with mental illness and the importance of family support and stigma resistance for minimizing the harmful impacts of stigma. The findings are important in the future design of public educational and stigma reduction programs.

Experience of stigma among mental health service users in Hong Kong: Are there changes between 2001 and 2017?

BACKGROUND: Public expenditure on mental health education has grown exponentially in the past two decades. Does the experience of stigma among people with mental health problems improve over time? Our study aims to compare the levels of perceived stigmatization, rejection experiences and stigma-coping among mental health service users in Hong Kong between 2001 and 2017 using longitudinal and repeated cross-sectional study design. METHOD: The baseline survey was completed by 193 psychiatric outpatients in 2001. They were traced for re-assessment in 2017. Another sample of 193 outpatients matched in age, gender and psychiatric diagnosis was recruited in 2017 for cross-sectional comparison. Participants completed a 39-item questionnaire on stigma experiences, Beck Depression Inventory and Disability Assessment Schedule at both time points. RESULTS: In total, 109 of 193 participants (56.5%) of the 2001 survey were re-assessed. No significant change in perceived stigmatization, rejection experiences and stigma-coping was found among the 109 participants interviewed in 2001 and 2017. For cross-sectional comparison, significant differences in two perceived stigma items were observed upon Bonferroni correction (chi-square test, p < .005) and remained significant after controlling for confounding factors by regression analysis. Improvements in perceived stigmatization were on marriage and friendship, while viewpoints on trustworthiness, dangerousness, devaluation, avoidance and personal failure remained unchanged, and there was no improvement in rejection experiences and stigma-coping. CONCLUSION: Positive attitude changes over time are unlikely to occur if there is no targeted intervention on stigma. Our findings highlight that evidence-based antistigma interventions are urgently needed.

Ursolic acid induces mitochondrial biogenesis through the activation of AMPK and PGC-1 in C2C12 myotubes: a possible mechanism underlying its beneficial effect on exercise endurance.

Mitochondrial biogenesis, which involves an increase in mitochondrial number and the overall capacity of oxidative phosphorylation, is a critical determinant of skeletal muscle function. Recent findings have shown that some natural products can enhance mitochondrial adaptation to aerobic exercise, which in turn improves exercise performance, presumably by delaying muscle fatigue. Ursolic acid (UA), a natural triterpene, is commonly found in various vegetables and fruits. In the current study, UA was shown to increase mitochondrial mass and ATP generation capacity, with a concomitant production of a low level of mitochondrial reactive oxygen species (ROS) in C2C12 myotubes. Mitochondrial ROS, in turn, activated the redox sensitive adenosine monophosphate-dependent protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1(PGC-1) pathway. The activation of AMPK/PGC-1 further increased the expression of cytochrome c oxidase (COX) and uncoupling protein 3. Animal studies showed that UA can also dose-dependently increase the endurance exercise capacity in mice, as assessed by a weight-loaded swimming test and a hanging wire test. Our findings suggest that UA may induce mitochondrial biogenesis through the activation of AMPK and PGC-1 pathways in skeletal muscle, thereby offering a promising prospect for its use to enhance exercise endurance and alleviating fatigue in humans.

Acute Pre-/Post-Treatment with 8th Day SOD-Like Supreme (a Free Radical Scavenging Health Product) Protects against Oxidant-Induced Injury in Cultured Cardiomyocytes and Hepatocytes In Vitro as Well as in Mouse Myocardium and Liver In Vivo.

8th Day superoxide dismutase (SOD)-Like Supreme (SOD-Like Supreme, a free radical scavenging health product) is an antioxidant-enriched fermentation preparation with free radical scavenging properties. In the present study, the cellular/tissue protective actions of SOD-Like Supreme against menadione toxicity in cultured H9c2 cardiomyocytes and in AML12 hepatocytes as well as oxidant-induced injury in the mouse myocardium and liver were investigated. SOD-Like Supreme was found to possess potent free radical scavenging activity in vitro as assessed by an oxygen radical absorbance capacity assay. Incubation with SOD-Like Supreme (0.5-3% (v/v)) was shown to protect against menadione-induced toxicity in H9c2 and AML12 cells, as evidenced by increases in cell viability. The ability of SOD-Like Supreme to protect against menadione cytotoxicity was associated with an elevation in the cellular reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio in menadione-challenged cells. Consistent with the cell-based studies, pre-/post-treatment with SOD-Like Supreme (0.69 and 2.06 mL/kg, three intermittent doses per day for two consecutive days) was found to protect against isoproterenol-induced myocardial injury and carbon tetrachloride hepatotoxicity in mice. The cardio/hepatoprotection afforded by SOD-Like Supreme was also paralleled by increases in myocardial/hepatic mitochondrial GSH/GSSG ratios in the SOD-Like Supreme-treated/oxidant-challenged mice. In conclusion, incubation/treatment with SOD-Like Supreme was found to protect against oxidant-induced injury in vitro and in vivo, presumably by virtue of its free radical scavenging activity.

Differential Action between Schisandrin A and Schisandrin B in Eliciting an Anti-Inflammatory Action: The Depletion of Reduced Glutathione and the Induction of an Antioxidant Response.

Schisandrin A (Sch A) and schisandrin B (Sch B) are active components of Schisandrae Fructus. We compared the biochemical mechanism underlying the anti-inflammatory action of Sch A and Sch B, using cultured lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and concanavalin (ConA)-stimulated mouse splenocytes. Pre-incubation with Sch A or Sch B produced an anti-inflammatory action in LPS-stimulated RAW264.7 cells, as evidenced by the inhibition of the pro-inflammatory c-Jun N-terminal kinases/p38 kinase/nuclear factor-κB signaling pathway as well as the suppression of various pro-inflammatory cytokines and effectors, with the extent of inhibition by Sch A being more pronounced. The greater activity of Sch A in anti-inflammatory response was associated with a greater decrease in cellular reduced glutathione (GSH) level and a greater increase in glutathione S-transferase activity than corresponding changes produced by Sch B. However, upon incubation, only Sch B resulted in the activation of the nuclear factor (erythroid-derived 2)-like factor 2 and the induction of a significant increase in the expression of thioredoxin (TRX) in RAW264.7 cells. The Sch B-induced increase in TRX expression was associated with the suppression of pro-inflammatory cytokines and effectors in LPS-stimulated macrophages. Studies in a mouse model of inflammation (carrageenan-induced paw edema) indicated that while long-term treatment with either Sch A or Sch B suppressed the extent of paw edema, only acute treatment with Sch A produced a significant degree of inhibition on the inflammatory response. Although only Sch A decreased the cellular GSH level and suppressed the release of pro-inflammatory cytokines and cell proliferation in ConA-simulated splenocytes in vitro, both Sch A and Sch B treatments, while not altering cellular GSH levels, suppressed ConA-stimulated splenocyte proliferation ex vivo. These results suggest that Sch A and Sch B may act differentially on activating GST/ depleting cellular GSH and inducing an antioxidant response involved in their anti-inflammatory actions.

A Cistanches Herba Fraction/ ß -Sitosterol Causes a Redox-Sensitive Induction of Mitochondrial Uncoupling and Activation of Adenosine Monophosphate-Dependent Protein Kinase/Peroxisome Proliferator-Activated Receptor γ Coactivator-1 in C2C12 Myotubes: A Possible Mechanism Underlying the Weight Reduction Effect.

Previous studies have demonstrated that HCF1, a semipurified fraction of Cistanches Herba, causes weight reduction in normal diet- and high fat diet-fed mice. The weight reduction was associated with the induction of mitochondrial uncoupling and changes in metabolic enzyme activities in mouse skeletal muscle. To further investigate the biochemical mechanism underlying the HCF1-induced weight reduction, the effect of HCF1 and its active component, ß-sitosterol (BSS), on C2C12 myotubes was examined. Incubation with HCF1/BSS caused a transient increase in mitochondrial membrane potential (MMP), possibly by fluidizing the mitochondrial inner membrane. The increase in MMP was paralleled to an increase in mitochondrial reactive oxygen species (ROS) production. Mitochondrial ROS, in turn, triggered a redox-sensitive induction of mitochondrial uncoupling by uncoupling protein 3 (UCP3). Biochemical analysis indicated that HCF1 was capable of activating an adenosine monophosphate-dependent protein kinase/peroxisome proliferator-activated receptor γ coactivator-1 pathway and thereby increased the expression of cytochrome c oxidase and UCP3. Animal studies using mitochondrial recoupler also confirmed the role of mitochondrial uncoupling in the HCF1-induced weight reduction. In conclusion, a HCF1/BSS causes the redox-sensitive induction of mitochondrial uncoupling and activation of AMPK/PGC-1 in C2C12 myotubes, with resultant reductions in body weight and adiposity by increased energy consumption.

ß-sitosterol protects against carbon tetrachloride hepatotoxicity but not gentamicin nephrotoxicity in rats via the induction of mitochondrial glutathione redox cycling.

Previous findings have demonstrated that ß-sitosterol (BSS), an active component of Cistanches Herba, protected against oxidant injury in H9c2 cardiomyocytes and in rat hearts by enhancing mitochondrial glutathione redox cycling, possibly through the intermediacy of mitochondrial reactive oxygen species production. We therefore hypothesized that BSS pretreatment can also confer tissue protection against oxidant injury in other vital organs such as liver and kidney of rats. In this study, the effects of BSS pretreatment on rat models of carbon tetrachloride (CCl4) hepatotoxicity and gentamicin nephrotoxicity were investigated. The findings showed that BSS pretreatment protected against CCl4-induced hepatotoxicity, but not gentamicin nephrotoxicity in rats. The hepatoprotection afforded by BSS was associated with the improvement in mitochondrial glutathione redox status, presumably through the glutathione reductase-mediated enhancement in mitochondrial glutathione redox cycling. The hepatoprotection afforded by BSS was also accompanied by the improved mitochondrial functional ability in rat livers. The inability of BSS to protect against gentamicin nephrotoxicity was likely due to the relatively low bioavailability of BSS in rat kidneys. BSS may serve as potential mitohormetic agent for the prevention of oxidative stress-induced injury in livers.

New insights into the chemical and biochemical basis of the "yang-invigorating" action of chinese yang-tonic herbs.

In the practice of traditional Chinese medicine, many Yang-tonic herbs have been used for retarding the decline in bodily function and delaying the onset of age-related diseases. Our earlier studies have demonstrated that Yang-invigorating herbs/formulations protect against oxidative injury in various organs and also extend the median lifespan in mice. This lifespan extension was associated with an upregulation of cellular antioxidant status including that of mitochondria whose functional capacity is also increased by "Yang-invigorating" herbs/formulations. In this paper, we propose that triterpenes and phytosterols, which are ubiquitously found in Yang-tonic herbs, may be the chemical entities responsible for enhancing mitochondrial functional and antioxidant capacity and thus the "Yang-invigorating" action. The biochemical mechanism underlying this "Yang-invigorating" action may involve a sustained production of low levels of mitochondrial reactive oxygen species (ROS) secondary to an increased activity of the electron transport chain, with the possible involvement of mitochondrial uncoupling. The increase in mitochondrial functional capacity can retard the decline in bodily function during aging, whereas the mitochondrial ROS production is instrumental in eliciting a glutathione antioxidant response via redox-sensitive signaling pathways, which can delay the onset of age-related diseases.

Effects of flavone 6-substitutions on GABAA receptors efficacy.

Flavones have been studied for their activities via benzodiazepine site on the type-A γ-aminobutyric acid (GABA(A)) receptors, for which knowledge on structure-efficacy relationships has been rather limited in comparison to that on structure-affinity relationships. The present study focused on flavone 6-substitution, implied in previous studies being relevant to efficacy. Structure analogs, each varying only at position 6, were compared, including 6-fluoroflavone, 6-chloroflavone, 6-bromoflavone, and 2'-hydroxyflavone analyzed in the present study, as well as 6,2'-dihydroxyflavone reported earlier. Radio-ligand binding assays, whole-cell patch-clamp, and mouse behavioral experiments were performed. In consistent with a previous report, the present whole-cell patch-clamp and animal behavior experiments demonstrated 6-bromoflavone to be a positive modulator at GABA(A) receptors acting through flumazenil-sensitive high-affinity benzodiazepine site. In contrast, the other two 6-haloflavones were both neutralizing modulators. In vitro electrophysiological and in vivo animal experiments showed that 2'-hydroxyflavone was a neutralizing modulator, different in efficacy from its structural analog, 6,2'-dihydroxyflavone, a negative modulator of GABA(A) receptors. The fact that flavone analogs differing only at position 6 showed drastically different pharmacological properties clearly points to 6-substitution being an important determinant of efficacy. The results suggest that a large width of the first atom on the 6-substituent favors a high binding affinity of the 6-substituted flavone, whereas a large overall volume of the 6-substituent favors positive modulator activity, which could be modified by, e.g., 2'-hydroxyl substitution. These findings have contributed to the understanding of quantitative structure-efficacy relationships for flavones acting at GABA(A) receptors, and hence facilitation of flavone-based drug development.

Expanded polyglutamine domain possesses nuclear export activity which modulates subcellular localization and toxicity of polyQ disease protein via exportin-1.

Polyglutamine (polyQ) diseases are a group of late-onset, progressive neurodegenerative disorders caused by CAG trinucleotide repeat expansion in the coding region of disease genes. The cell nucleus is an important site of pathology in polyQ diseases, and transcriptional dysregulation is one of the pathologic hallmarks observed. In this study, we showed that exportin-1 (Xpo1) regulates the nucleocytoplasmic distribution of expanded polyQ protein. We found that expanded polyQ protein, but not its unexpanded form, possesses nuclear export activity and interacts with Xpo1. Genetic manipulation of Xpo1 expression levels in transgenic Drosophila models of polyQ disease confirmed the specific nuclear export role of Xpo1 on expanded polyQ protein. Upon Xpo1 knockdown, the expanded polyQ protein was retained in the nucleus. The nuclear disease protein enhanced polyQ toxicity by binding to heat shock protein (hsp) gene promoter and abolished hsp gene induction. Further, we uncovered a developmental decline of Xpo1 protein levels in vivo that contributes to the accumulation of expanded polyQ protein in the nucleus of symptomatic polyQ transgenic mice. Taken together, we first showed that Xpo1 is a nuclear export receptor for expanded polyQ domain, and our findings establish a direct link between protein nuclear export and the progressive nature of polyQ neurodegeneration.

GABA(A) receptor subtype selectivity underlying anxiolytic effect of 6-hydroxyflavone.

6-Hydroxyflavone (6HF), a naturally occurring flavonoid, was previously reported to bind to type A gamma-aminobutyric acid (GABA(A)) receptors benzodiazepine (BZ) site with moderate binding affinity. In the present study, we showed that 6HF partially potentiated GABA-induced currents in native GABA(A) receptors expressed in cortical neurons via BZ site, as the enhancement was blocked by the antagonist flumazenil. Furthermore, in patch clamp studies, 6HF displayed significant preference for alpha(2)- and alpha(3)-containing subtypes, which were thought to mediate anxiolytic effect, compared to alpha(1)- and alpha(5)-containing subtypes expressed in HEK 293T cells. In mice, 6HF exhibited anxiolytic-like effect in the elevated plus-maze test, unaccompanied at anxiolytic doses by the sedative, cognitive impairing, myorelaxant, motor incoordination and anticonvulsant effects commonly associated with classical BZs when tested in the hole-board, step-through passive avoidance, horizontal wire, rotarod, and pentylenetetrazol (PTZ)-induced seizure tests, respectively. The findings therefore identified 6HF as a promising drug candidate for the treatment of anxiety-like disorders.

The ion channel activity of the SARS-coronavirus 3a protein is linked to its pro-apoptotic function.

The severe acute respiratory syndrome-coronavirus (SARS-CoV) caused an outbreak of atypical pneumonia in 2003. The SARS-CoV viral genome encodes several proteins which have no homology to proteins in any other coronaviruses, and a number of these proteins have been implicated in viral cytopathies. One such protein is 3a, which is also known as X1, ORF3 and U274. 3a expression is detected in both SARS-CoV infected cultured cells and patients. Among the different functions identified, 3a is a capable of inducing apoptosis. We previously showed that caspase pathways are involved in 3a-induced apoptosis. In this study, we attempted to find out protein domains on 3a that are essential for its pro-apoptotic function. Protein sequence analysis reveals that 3a possesses three major protein signatures, the cysteine-rich, Yxx phi and diacidic domains. We showed that 3a proteins carrying respective mutations in these protein domains exhibit reduced pro-apoptotic activities, indicating the importance of these domains on 3a's pro-apoptotic function. It was previously reported that 3a possesses potassium ion channel activity. We further demonstrated that the blockade of 3a's potassium channel activity abolished caspase-dependent apoptosis. This report provides the first evidence that ion channel activity of 3a is required for its pro-apoptotic function. As ion channel activity has been reported to regulate apoptosis in different pathologic conditions, finding ways to modulate the ion channel activity may offer a new direction toward the inhibition of apoptosis triggered by SARS-CoV.

Human receptor for activated protein kinase C1 associates with polyglutamine aggregates and modulates polyglutamine toxicity.

Formation of SDS-insoluble protein aggregates in affected neurons is a cellular pathological feature of polyglutamine (polyQ) disease. We identified a multi-WD-domain protein, receptor for activated protein kinase C1 (RACK1), as a novel polyQ aggregate component from a Drosophila transgenic polyQ disease model. We showed that WD domains were crucial determinants for the recruitment of RACK1 to polyQ aggregates. Over-expression of the human RACK1 protein suppressed polyQ-induced neurodegeneration in vivo. This is the first report to demonstrate the involvement of WD-domain proteins in polyQ pathogenesis, and the proteomic approach described here can be applied to the investigation of other protein aggregation disorders including Alzheimer's and Parkinson's diseases.

Dexras1 interacts with FE65 to regulate FE65-amyloid precursor protein-dependent transcription.

FE65 is an adaptor protein that binds to and forms a transcriptionally active complex with the gamma-secretase-derived amyloid precursor protein (APP) intracellular domain. The regulatory mechanisms of FE65-APP-mediated transcription are still not clear. In this report, we demonstrate that Dexras1, a Ras family small G protein, binds to FE65 PTB2 domain and potently suppresses the FE65-APP-mediated transcription. The suppression is not via competition for binding of FE65 between Dexras1 and APP because the two proteins can simultaneously bind to the FE65 PTB2 domain. Phosphorylation of FE65 tyrosine 547 within the PTB2 domain has been shown to enhance FE65-APP-mediated transcription but not to influence binding to APP. Here we find that this phosphorylation event reduces the binding between Dexras1 and FE65. We also demonstrate that Dexras1 inhibits the FE65-APP-mediated transcription of glycogen synthase kinase 3beta (GSK3 beta). Moreover, small interfering RNA knockdown of Dexras1 enhances GSK3 beta expression and increases phosphorylation of Tau, a GSK3 beta substrate. Thus, Dexras1 functions as a suppressor of FE65-APP-mediated transcription, and FE65 tyrosine 547 phosphorylation enhances FE65-APP-mediated transcription, at least in part, by modulating the interaction between FE65 and Dexras1. These findings reveal a novel regulatory mechanism for FE65-APP-mediated signaling.