Contribution of the cyclic nucleotide gated channel subunit, CNG-3, to olfactory plasticity in Caenorhabditis elegans.

In Caenorhabditis elegans, the AWC neurons are thought to deploy a cGMP signaling cascade in the detection of and response to AWC sensed odors. Prolonged exposure to an AWC sensed odor in the absence of food leads to reversible decreases in the animal's attraction to that odor. This adaptation exhibits two stages referred to as short-term and long-term adaptation. Previously, the protein kinase G (PKG), EGL-4/PKG-1, was shown necessary for both stages of adaptation and phosphorylation of its target, the beta-type cyclic nucleotide gated (CNG) channel subunit, TAX-2, was implicated in the short term stage. Here we uncover a novel role for the CNG channel subunit, CNG-3, in short term adaptation. We demonstrate that CNG-3 is required in the AWC for adaptation to short (thirty minute) exposures of odor, and contains a candidate PKG phosphorylation site required to tune odor sensitivity. We also provide in vivo data suggesting that CNG-3 forms a complex with both TAX-2 and TAX-4 CNG channel subunits in AWC. Finally, we examine the physiology of different CNG channel subunit combinations

How does gender influence the recognition of cardiovascular risk and adherence to self-care recommendations? : a study in polish primary care

Background: Studies have shown a correlation between gender and an ability to change lifestyle to reduce the risk of disease. However, the results of these studies are ambiguous, especially where a healthy lifestyle is concerned. Additionally, health behaviors are strongly modified by culture and the environment. Psychological factors also substantially affect engagement with disease-related lifestyle interventions. This study aimed to examine whether there are differences between men and women in the frequency of health care behavior for the purpose of reducing cardiovascular risk (CVR), as well as cognitive appraisal of this type of risk. We also aimed to identify the psychological predictors of engaging in recommended behavior for reducing the risk of cardiovascular disease after providing information about this risk in men and women. Methods: A total of 134 consecutive eligible patients in a family practice entered a longitudinal study. At initial consultation, the individual’s CVR and associated health burden was examined, and preventive measures were recommended by the physician. Self-care behavior, cognitive appraisal of risk, and coping styles were then assessed using psychological questionnaires. Six months after the initial data collection, the frequency of subjects’ self-care behavior was examined. Results: We found an increase in health care behavior after providing information regarding the rate of CVR in both sexes; this increase was greater for women than for men. Women followed self-care guidelines more often than men, particularly for preventive measures and dietary advice. Women were more inclined to recognize their CVR as a challenge. Coping style, cognitive appraisal, age, level of health behaviors at baseline and CVR values accounted for 48% of the variance in adherence to self-care guidelines in women and it was 52% in men. In women, total risk of CVD values were most important, while in men, cognitive appraisal of harm/loss was most important. Conclusions: Different predictors of acquisition of health behavior are encountered in men and women. Our results suggest that gender-adjusted motivation models influencing the recognition process need to be considered to optimize compliance in patients with CVR

Predicting Breast Cancer Response to Neoadjuvant Chemotherapy Using Pretreatment Diffuse Optical Spectroscopic-Texture Analysis

Purpose: Diffuse optical spectroscopy (DOS) has been demonstrated capable of monitoring response to neoadjuvant chemotherapy (NAC) in locally advanced breast cancer (LABC) patients. In this study, we evaluate texture features of pre-treatment DOS functional maps for predicting LABC response to NAC. Methods: LABC patients (n = 37) underwent DOS-breast imaging before starting neoadjuvant chemotherapy. Breast-tissue parametric maps were constructed and texture analyses were performed based on grey level co-occurrence matrices (GLCM) for feature extraction. Ground-truth labels as responders (R) or non-responders (NR) were assigned to patients based on Miller-Payne pathological response criteria. The capability of DOS-textural features computed on volumetric tumour data before the start of treatment (i.e. “pre-treatment”) to predict patient responses to NAC was evaluated using a leave-one-out validation scheme at subject level. Data were analysed using a logistic regression, naïve Bayes, and k-nearest neighbour (k-NN) classifiers. Results: Data indicated that textural characteristics of pre-treatment DOS parametric maps can differentiate between treatment response outcomes. The HbO2-homogeneity resulted in the highest accuracy amongst univariate parameters in predicting response to chemotherapy: sensitivity (%Sn) and specificity (%Sp) were 86.5 and 89.0%, respectively and accuracy was 87.8%. The highest predictors using multivariate (binary) combination features were the Hb-Contrast + HbO2-Homogeneity which resulted in a %Sn/%Sp = 78.0/81.0% and an accuracy of 79.5%. Conclusions: This study demonstrated that pre-treatment tumour DOS-texture features can predict breast cancer response to NAC and potentially guide treatments

Increasing vegetable intakes: rationale and systematic review of published interventions

Purpose While the health benefits of a high fruit and vegetable consumption are well known and considerable work has attempted to improve intakes, increasing evidence also recognises a distinction between fruit and vegetables, both in their impacts on health and in consumption patterns. Increasing work suggests health benefits from a high consumption specifically of vegetables, yet intakes remain low, and barriers to increasing intakes are prevalent making intervention difficult. A systematic review was undertaken to identify from the published literature all studies reporting an intervention to increase intakes of vegetables as a distinct food group. Methods Databases—PubMed, PsychInfo and Medline—were searched over all years of records until April 2015 using pre-specified terms. Results Our searches identified 77 studies, detailing 140 interventions, of which 133 (81 %) interventions were conducted in children. Interventions aimed to use or change hedonic factors, such as taste, liking and familiarity (n = 72), use or change environmental factors (n = 39), use or change cognitive factors (n = 19), or a combination of strategies (n = 10). Increased vegetable acceptance, selection and/or consumption were reported to some degree in 116 (83 %) interventions, but the majority of effects seem small and inconsistent. Conclusions Greater percent success is currently found from environmental, educational and multi-component interventions, but publication bias is likely, and long-term effects and cost-effectiveness are rarely considered. A focus on long-term benefits and sustained behaviour change is required. Certain population groups are also noticeably absent from the current list of tried interventions

Molecular mechanism for 3:1 subunit stoichiometry of rod cyclic nucleotide-gated ion channels

Molecular determinants of ion channel tetramerization are well characterized, but those involved in heteromeric channel assembly are less clearly understood. The heteromeric composition of native channels is often precisely controlled. Cyclic nucleotide-gated (CNG) channels from rod photoreceptors exhibit a 3:1 stoichiometry of CNGA1 and CNGB1 subunits that tunes the channels for their specialized role in phototransduction. Here we show, using electrophysiology, fluorescence, biochemistry, and X-ray crystallography, that the mechanism for this controlled assembly is the formation of a parallel 3-helix coiled-coil domain of the carboxy-terminal leucine zipper region of CNGA1 subunits, constraining the channel to contain three CNGA1 subunits, followed by preferential incorporation of a single CNGB1 subunit. Deletion of the carboxy-terminal leucine zipper domain relaxed the constraint and permitted multiple CNGB1 subunits in the channel. The X-ray crystal structures of the parallel 3-helix coiled-coil domains of CNGA1 and CNGA3 subunits were similar, suggesting that a similar mechanism controls the stoichiometry of cone CNG channels

Trafficking-Deficient G572R-hERG and E637K-hERG Activate Stress and Clearance Pathways in Endoplasmic Reticulum

Background: Long QT syndrome type 2 (LQT2) is the second most common type of all long QT syndromes. It is well-known that trafficking deficient mutant human ether-a-go-go-related gene (hERG) proteins are often involved in LQT2. Cells respond to misfolded and trafficking-deficient proteins by eliciting the unfolded protein response (UPR) and Activating Transcription Factor (ATF6) has been identified as a key regulator of the mammalian UPR. In this study, we investigated the role of ER chaperone proteins (Calnexin and Calreticulin) in the processing of G572R-hERG and E637K-hERG mutant proteins. Methods: pcDNA3-WT-hERG, pcDNA3-G572R-hERG and pcDNA3-E637K-hERG plasmids were transfected into U2OS and HEK293 cells. Confocal microscopy and western blotting were used to analyze subcellular localization and protein expression. Interaction between WT or mutant hERGs and Calnexin/Calreticulin was tested by coimmunoprecipitation. To assess the role of the ubiquitin proteasome pathway in the degradation of mutant hERG proteins, transfected HEK293 cells were treated with proteasome inhibitors and their effects on the steady state protein levels of WT and mutant hERGs were examined. Conclusion: Our results showed that levels of core-glycosylated immature forms of G572R-hERG and E637K-hERG in association with Calnexin and Calreticulin were higher than that in WT-hERG. Both mutant hERG proteins could activate the UPR by upregulating levels of active ATF6. Furthermore, proteasome inhibition increased the levels of core-glycosylated immature forms of WT and mutant hERGs. In addition, interaction between mutant hERGs and Calnexin/Calreticulin wa

Changes in Channel Trafficking and Protein Stability Caused by LQT2 Mutations in the PAS Domain of the HERG Channel

Inherited human long-QT2 syndrome (LQTS) results from mutations in the gene encoding the HERG channel. Several LQT2-associated mutations have been mapped to the amino terminal cytoplasmic Per-Arnt-Sim (PAS) domain of the HERG1a channel subunit. Here we have characterized the trafficking properties of some LQT2-associated PAS domain mutants and analyzed rescue of the trafficking mutants by low temperature (27°C) or by the pore blocker drug E4031. We show that the LQT2-associated mutations in the PAS domain of the HERG channel display molecular properties that are distinct from the properties of LQT2-associated mutations in the trans-membrane region. Unlike the latter, many of the tested PAS domain LQT2-associated mutations do not result in trafficking deficiency of the channel. Moreover, the majority of the PAS domain mutations that cause trafficking deficiencies are not rescued by a pore blocking drug. We have also explored the in vitro folding stability properties of isolated mutant PAS domain proteins using a thermal unfolding fluorescence assay and a chemical unfolding assay

The S4–S5 Linker Acts as a Signal Integrator for hERG K+ Channel Activation and Deactivation Gating

Human ether-à-go-go-related gene (hERG) K+ channels have unusual gating kinetics. Characterised by slow activation/deactivation but rapid inactivation/recovery from inactivation, the unique gating kinetics underlie the central role hERG channels play in cardiac repolarisation. The slow activation and deactivation kinetics are regulated in part by the S4–S5 linker, which couples movement of the voltage sensor domain to opening of the activation gate at the distal end of the inner helix of the pore domain. It has also been suggested that cytosolic domains may interact with the S4–S5 linker to regulate activation and deactivation kinetics. Here, we show that the solution structure of a peptide corresponding to the S4–S5 linker of hERG contains an amphipathic helix. The effects of mutations at the majority of residues in the S4–S5 linker of hERG were consistent with the previously identified role in coupling voltage sensor movement to the activation gate. However, mutations to Ser543, Tyr545, Gly546 and Ala548 had more complex phenotypes indicating that these residues are involved in additional interactions. We propose a model in which the S4–S5 linker, in addition to coupling VSD movement to the activation gate, also contributes to interactions that stabilise the closed state and a separate set of interactions that stabilise the open state. The S4–S5 linker therefore acts as a signal integrator and plays a crucial role in the slow deactivation kinetics of the channel

The N–Terminal Tail of hERG Contains an Amphipathic α–Helix That Regulates Channel Deactivation

The cytoplasmic N–terminal domain of the human ether–a–go–go related gene (hERG) K+ channel is critical for the slow deactivation kinetics of the channel. However, the mechanism(s) by which the N–terminal domain regulates deactivation remains to be determined. Here we show that the solution NMR structure of the N–terminal 135 residues of hERG contains a previously described Per–Arnt–Sim (PAS) domain (residues 26–135) as well as an amphipathic α–helix (residues 13–23) and an initial unstructured segment (residues 2–9). Deletion of residues 2–25, only the unstructured segment (residues 2–9) or replacement of the α–helix with a flexible linker all result in enhanced rates of deactivation. Thus, both the initial flexible segment and the α–helix are required but neither is sufficient to confer slow deactivation kinetics. Alanine scanning mutagenesis identified R5 and G6 in the initial flexible segment as critical for slow deactivation. Alanine mutants in the helical region had less dramatic phenotypes. We propose that the PAS domain is bound close to the central core of the channel and that the N–terminal α–helix ensures that the flexible tail is correctly orientated for interaction with the activation gating machinery to stabilize the open state of the channel

Performance in Physical Education and Health Impairment 30 Years Later—A Community Based Cohort Study

Objective: A main purpose of physical education (PE) in school is to promote future health. However, there is very limited evidence of the effects of PE on the adult health. We hypothesized that a low performance in PE was associated with an increased risk of health impairment by middle age. Methods: We performed a cohort study in a community-based setting in Sweden spanning over three decades. We followed up on 1712 of 2225 students (76.9%) who in 1974–1976 graduated with a grade in PE after 9 years of education (mean subject age 16 years). The grade in PE (compulsory subject) was retrieved from municipal archives. We defined three proxies for health impairment: total number of visits to primary care physicians in 2003–2007, having been hospitalized 2003–2007, and total number of days with sick leave in 2004–2007. Using binomial regression models, we adjusted the risk estimates for level of education and occupation. Subjects with an average grade in PE served as reference category. Results: In both the crude and adjusted model, women with a low grade in PE had more physician visits (adjusted IRR 1.30, 95 % confidence interval 1.06–1.60) and an increased number of days with sick leave (adjusted IRR 1.44, 1.05–1.95). An increased, although not significant, risk was also observed for having received in-patient care (adjusted RR 1.26; 0.88–1.80). No significant results or similar pattern were observed in men. Conclusion: Women with a low grade in PE in adolescence seem to have an increased risk of health impairment by middl