Kv7 and Kv11 channels in myometrial regulation.

Ion channels play a key role in defining myometrial contractility. Modulation of ion channel populations is proposed to underpin gestational changes in uterine contractility associated with the transition from uterine quiescence to active labour. Of the myriad ion channels present in the uterus, this article will focus upon potassium channels encoded by the KCNQ genes and ether-à-go-go-related (ERG) genes. Voltage-gated potassium channels encoded by KCNQ and ERG (termed Kv7 and Kv11, respectively) are accepted as major determinants of neuronal excitability and the duration of the cardiac action potential. However, there is now growing appreciation that these ion channels have a major functional impact in vascular and non-vascular smooth muscle. Moreover, Kv7 channels may be potential therapeutic targets for the treatment of preterm labour

Predicting Head Pose from Speech with a Conditional Variational Autoencoder

Natural movement plays a significant role in realistic speech animation. Numerous studies have demonstrated the contribution visual cues make to the degree we, as human observers, find an animation acceptable. Rigid head motion is one visual mode that universally co-occurs with speech, and so it is a reasonable strategy to seek a transformation from the speech mode to predict the head pose. Several previous authors have shown that prediction is possible, but experiments are typically confined to rigidly produced dialogue. Natural, expressive, emotive and prosodic speech exhibit motion patterns that are far more difficult to predict with considerable variation in expected head pose. Recently, Long Short Term Memory (LSTM) networks have become an important tool for modelling speech and natural language tasks. We employ Deep Bi-Directional LSTMs (BLSTM) capable of learning long-term structure in language, to model the relationship that speech has with rigid head motion. We then extend our model by conditioning with prior motion. Finally, we introduce a generative head motion model, conditioned on audio features using a Conditional Variational Autoencoder (CVAE). Each approach mitigates the problems of the one to many mapping that a speech to head pose model must accommodat

Protective role of Kv7 channels in oxygen and glucose deprivation-induced damage in rat caudate brain slices

Ischemic stroke can cause striatal dopamine efflux that contributes to cell death. Since Kv7 potassium channels regulate dopamine release, we investigated the effects of their pharmacological modulation on dopamine efflux, measured by fast cyclic voltammetry (FCV), and neurotoxicity, in Wistar rat caudate brain slices undergoing oxygen and glucose deprivation (OGD). The Kv7 activators retigabine and ICA27243 delayed the onset, and decreased the peak level of dopamine efflux induced by OGD; and also decreased OGD-induced damage measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Retigabine also reduced OGD-induced necrotic cell death evaluated by lactate dehydrogenase activity assay. The Kv7 blocker linopirdine increased OGD-evoked dopamine efflux and OGD-induced damage, and attenuated the effects of retigabine. Quantitative-PCR experiments showed that OGD caused an ~ 6-fold decrease in Kv7.2 transcript, while levels of mRNAs encoding for other Kv7 subunits were unaffected; western blot experiments showed a parallel reduction in Kv7.2 protein levels. Retigabine also decreased the peak level of dopamine efflux induced by L-glutamate, and attenuated the loss of TTC staining induced by the excitotoxin. These results suggest a role for Kv7.2 in modulating ischemia-evoked caudate damage

Exploring a physiotherapy well-being review to deliver community-based rehabilitation in patients with pulmonary hypertension

Background: Highly structured, supervised exercise training has been shown to be beneficial in patients with pulmonary hypertension. Despite evidence of the effectiveness of community-based rehabilitation in other cardiopulmonary diseases there are limited data in patients with pulmonary hypertension. Methods: This prospective study evaluated the intervention of a physiotherapist well-being review in patients with pulmonary hypertension who had been established on targeted drug therapy for between 3 and 12 months. The intervention included a detailed consultation assessing functional, social and motivational status to identify individual patient rehabilitation goals and facilitate tailored referrals to community-based services. Results: One hundred and thirty eight patients (79% pulmonary arterial hypertension, 17% chronic thromboembolic disease), age 67±14 years, diagnosed over a one year period were evaluated between July 2017 and January 2018. Fifty-two percent of patients were referred to community-based pulmonary rehabilitation programmes, 19% received other forms of community rehabilitation, 17% were given exercise advice, 5% had an assessment of social support and 7% declined any intervention. At the end of the study 32% of patients were undertaking independent exercise. Conclusion: This study has identified that the majority of patients with pulmonary hypertension who are optimised on targeted drug therapy have rehabilitation needs. The use of a physiotherapy well-being review can identify this need and facilitate access to community-based rehabilitation. Further research is required to evaluate the efficacy of such interventions in pulmonary hypertension

Mechanism of the Inhibition of Ca2+-Activated Cl− Currents by Phosphorylation in Pulmonary Arterial Smooth Muscle Cells

The aim of the present study was to provide a mechanistic insight into how phosphatase activity influences calcium-activated chloride channels in rabbit pulmonary artery myocytes. Calcium-dependent Cl− currents (IClCa) were evoked by pipette solutions containing concentrations between 20 and 1000 nM Ca2+ and the calcium and voltage dependence was determined. Under control conditions with pipette solutions containing ATP and 500 nM Ca2+, IClCa was evoked immediately upon membrane rupture but then exhibited marked rundown to ∼20% of initial values. In contrast, when phosphorylation was prohibited by using pipette solutions containing adenosine 5′-(β,γ-imido)-triphosphate (AMP-PNP) or with ATP omitted, the rundown was severely impaired, and after 20 min dialysis, IClCa was ∼100% of initial levels. IClCa recorded with AMP-PNP–containing pipette solutions were significantly larger than control currents and had faster kinetics at positive potentials and slower deactivation kinetics at negative potentials. The marked increase in IClCa was due to a negative shift in the voltage dependence of activation and not due to an increase in the apparent binding affinity for Ca2+. Mathematical simulations were carried out based on gating schemes involving voltage-independent binding of three Ca2+, each binding step resulting in channel opening at fixed calcium but progressively greater “on” rates, and voltage-dependent closing steps (“off” rates). Our model reproduced well the Ca2+ and voltage dependence of IClCa as well as its kinetic properties. The impact of global phosphorylation could be well mimicked by alterations in the magnitude, voltage dependence, and state of the gating variable of the channel closure rates. These data reveal that the phosphorylation status of the Ca2+-activated Cl− channel complex influences current generation dramatically through one or more critical voltage-dependent steps

Age-related changes in femoral head trabecular microarchitecture

Osteoporosis is a prevalent bone condition, characterised by low bone mineral density and increased fracture risk. Currently, the gold standard for identifying osteoporosis and increased fracture risk is through quantification of bone mineral density using dual energy X-ray absorption. However, many studies have shown that bone strength, and consequently the probability of fracture, is a combination of both bone mass and bone ‘quality’ (architecture and material chemistry). Although the microarchitecture of both non-fracture and osteoporotic bone has been previously investigated, many of the osteoporotic studies are constrained by factors such as limited sample number, use of ovariectomised animal models, and lack of male and female discrimination. This study reports significant differences in bone quality with respect to the microarchitecture between fractured and non-fractured human femur specimens. Micro-computed tomography was utilised to investigate the microarchitecture of femoral head trabecular bone from a relatively large cohort of non-fracture and fracture human donors. Various microarchitectural parameters have been determined for both groups, providing an understanding of the differences between fracture and non -fracture material. The microarchitecture of non-fracture and fracture bone tissue is shown to be significantly different for many parameters. Differences between sexes also exist, suggesting differences in remodelling between males and females in the fracture group. The results from this study will, in the future, be applied to develop a fracture model which encompasses bone density, architecture and material chemical properties for both female and male tissues

Novel expression and regulation of voltage-dependent potassium (KV7) channels in placentae from women with preeclampsia

Preeclampsia is associated with structural/functional alterations in placental and maternal vasculature. KV7 (voltage-dependant potassium channels encoded by KCNQ1-5 genes) have been detected in several types of blood vessels where they promote vascular relaxation. KV7 channel function can be modulated by KCNE1-5 encoded accessory proteins. The aim of this study was to determine whether KCNQ and KCNE genes are differentially expressed in placentae from women with preeclampsia compared to normotensive controls and to examine any differences in those who delivered preterm (<37 weeks’) or term. Placental biopsies (from midway between the cord and periphery) were obtained, with consent, from White European control (n=24, term) and preeclamptic (n=22; of whom 8 delivered before 37 weeks’) women. KCNQ/KCNE and GAPDH mRNA expression was determined by qRT-PCR. Protein expression/localisation was assessed using immunohistochemistry. KCNQ3 and KCNE5 mRNA expression was significantly up-regulated in preeclampsia (median [IQR]: 1.942 [0.905, 3.379]) versus controls (0.159 [0.088, 0.288]; p=0.001) and exhibited a strong positive correlation with each other (p<0.001) suggesting a novel heterodimer. Enhanced protein expression of KCNQ3 and KCNE5 in preeclampsia was confirmed with localisation mainly restricted to the syncytiotrophoblast. KCNQ4 and KCNE1 isoforms were suppressed in placenta from term preeclamptic women versus controls (p≤0.05). KCNQ1 mRNA expression was increased and KCNQ5 decreased in the preterm preeclamptic group versus controls (p<0.05). In summary, KV7 channels are expressed and markedly modulated in placenta from preeclamptic women. Differential expression of isoforms may lead to altered cell proliferation. The correlation between KCNQ3 and KCNE5 expression is indicative of a novel channel complex and warrants further investigation

Angiotensin II promotes KV7.4 channels degradation through reduced interaction with HSP90 (heat shock protein 90)

Voltage-gated Kv 7.4 channels have been implicated in vascular smooth muscle cells’ activity because they modulate basal arterial contractility, mediate responses to endogenous vasorelaxants, and are downregulated in several arterial beds in different models of hypertension. Angiotensin II (Ang II) is a key player in hypertension that affects the expression of several classes of ion channels. In this study, we evaluated the effects of Ang II on the expression and function of vascular Kv 7.4. Western blot and quantitative polymerase chain reaction revealed that in whole rat mesenteric artery, Ang II incubation for 1 to 7 hours decreased Kv 7.4 protein expression without reducing transcript levels. Moreover, Ang II decreased XE991 (Kv 7)–sensitive currents and attenuated membrane potential hyperpolarization and relaxation induced by the Kv 7 activator ML213. Ang II also reduced Kv 7.4 staining at the plasma membrane of vascular smooth muscle cells. Proteasome inhibition with MG132 prevented Ang II–induced decrease of Kv 7.4 levels and counteracted the functional impairment of ML213-induced relaxation in myography experiments. Proximity ligation assays showed that Ang II impaired the interaction of Kv 7.4 with the molecular chaperone HSP90 (heat shock protein 90), enhanced the interaction of Kv 7.4 with the E3 ubiquitin ligase CHIP (C terminus of Hsp70-interacting protein), and increased Kv 7.4 ubiquitination. Similar alterations were found in mesenteric vascular smooth muscle cells isolated from Ang II–infused mice. The effect of Ang II was emulated by 17-AAG (17-demethoxy-17-(2-propenylamino) geldanamycin) that inhibits HSP90 interactions with client proteins. These results show that Ang II downregulates Kv 7.4 by altering protein stability through a decrease of its interaction with HSP90. This leads to the recruitment of CHIP and Kv 7.4 ubiquitination and degradation via the proteasom

The U&I study: study protocol for a feasibility randomised controlled trial of a pre-cognitive behavioural therapy digital ‘informed choice’ intervention to improve attitudes towards uptake and implementation of CBT for psychosis

Background: At least 40% of people with psychosis have persistent distressing symptoms despite optimal medication treatment. Cognitive Behaviour Therapy for psychosis (CBTp) is the only NICE recommended individual therapy for psychosis, with effects on symptoms, distress and quality of life. Yet fewer than 20% of service-users receive it and 94% of trusts struggle to provide it. Of those offered it, 22-43% refuse or do not attend. We have developed a new pre-CBTp informed choice intervention to address knowledge and attitudes that influence uptake and implementation and now want to test it in a feasibility trial. Methods: The design is a 2-arm, feasibility RCT, with 1:1 randomisation, stratified by participant group and site. Participants are 40 psychosis patients and 40 clinicians, who are ambivalent towards uptake or implementation of CBTp. Sites are community and inpatient services in Sussex and London. The intervention is a pre-CBT digital psychoeducation intervention designed to address identified knowledge and attitudinal barriers to uptake and implementation of CBTp, incorporating behaviour change mechanisms, and supported by animated introductory, patient and clinician stories. The comparator is the NHS choices website for CBT. The primary aim is to assess clinical feasibility (recruitment, randomization, acceptability, use, delivery, outcome measurement, retention). A secondary aim is a preliminary evaluation of efficacy. Outcomes will be assessed at baseline, post-intervention, and one-month follow up (blind to treatment arm). The primary efficacy outcome is likelihood of offering/taking up CBTp. Secondary outcomes include knowledge and attitudes towards CBTp; illness perceptions; empowerment; psychological wellbeing (patients only); CBTp implementation (clinicians only). Use of the intervention and CBT behaviours during the follow-up period will be recorded, and captured in a feedback questionnaire. Use, acceptability and experience of outcome assessment will be explored in qualitative interviews with participants (n = 6 per group). The efficacy evaluation will report descriptive data, key model parameters and 95% Highest Probability Density intervals in a Bayesian growth model. Discussion: This is the first feasibility trial of a digital ‘informed choice’ decision aid for the implementation of CBTp. If the trial proves feasible and demonstrates preliminary evidence of efficacy, a large multi-site trial will be warranted