TMEM16A Potentiation: A Novel Therapeutic Approach for the Treatment of Cystic Fibrosis.

Rationale: Enhancing non-CFTR (cystic fibrosis transmembrane conductance regulator)-mediated anion secretion is an attractive therapeutic approach for the treatment of cystic fibrosis (CF) and other mucoobstructive diseases.Objectives: To determine the effects of TMEM16A potentiation on epithelial fluid secretion and mucociliary clearance.Methods: The effects of a novel low-molecular-weight TMEM16A potentiator (ETX001) were evaluated in human cell and animal models of airway epithelial function and mucus transport.Measurements and Main Results: Potentiating the activity of TMEM16A with ETX001 increased the Ca2+-activated Cl- channel activity and anion secretion in human bronchial epithelial (HBE) cells from patients with CF without impacting calcium signaling. ETX001 rapidly increased fluid secretion and airway surface liquid height in CF-HBE cells under both static conditions and conditions designed to mimic the shear stress associated with tidal breathing. In ovine models of mucus clearance (tracheal mucus velocity and mucociliary clearance), inhaled ETX001 was able to accelerate clearance both when CFTR function was reduced by administration of a pharmacological blocker and when CFTR was fully functional.Conclusions: Enhancing the activity of TMEM16A increases epithelial fluid secretion and enhances mucus clearance independent of CFTR function. TMEM16A potentiation is a novel approach for the treatment of patients with CF and non-CF mucoobstructive diseases.

Variomics screen identifies the re-entrant loop of the calcium-activated chloride channel ANO1 that facilitates channel activation.

The calcium-activated chloride channel ANO1 regulates multiple physiological processes. However, little is known about the mechanism of channel gating and regulation of ANO1 activity. Using a high-throughput, random mutagenesis-based variomics screen, we generated and functionally characterized ∼6000 ANO1 mutants and identified novel mutations that affected channel activity, intracellular trafficking, or localization of ANO1. Mutations such as S741T increased ANO1 calcium sensitivity and rendered ANO1 calcium gating voltage-independent, demonstrating a critical role of the re-entrant loop in coupling calcium and voltage sensitivity of ANO1 and hence in regulating ANO1 activation. Our data present the first unbiased and comprehensive study of the structure-function relationship of ANO1. The novel ANO1 mutants reported have diverse functional characteristics, providing new tools to study ANO1 function in biological systems, paving the path for a better understanding of the function of ANO1 and its role in health and diseases.

Calcium-activated chloride channel ANO1 promotes breast cancer progression by activating EGFR and CAMK signaling.

The calcium-activated chloride channel anoctamin 1 (ANO1) is located within the 11q13 amplicon, one of the most frequently amplified chromosomal regions in human cancer, but its functional role in tumorigenesis has remained unclear. The 11q13 region is amplified in ∼15% of breast cancers. Whether ANO1 is amplified in breast tumors, the extent to which gene amplification contributes to ANO1 overexpression, and whether overexpression of ANO1 is important for tumor maintenance have remained unknown. We have found that ANO1 is amplified and highly expressed in breast cancer cell lines and primary tumors. Amplification of ANO1 correlated with disease grade and poor prognosis. Knockdown of ANO1 in ANO1-amplified breast cancer cell lines and other cancers bearing 11q13 amplification inhibited proliferation, induced apoptosis, and reduced tumor growth in established cancer xenografts. Moreover, ANO1 chloride channel activity was important for cell viability. Mechanistically, ANO1 knockdown or pharmacological inhibition of its chloride-channel activity reduced EGF receptor (EGFR) and calmodulin-dependent protein kinase II (CAMKII) signaling, which subsequently attenuated AKT, v-src sarcoma viral oncogene homolog (SRC), and extracellular signal-regulated kinase (ERK) activation in vitro and in vivo. Our results highlight the involvement of the ANO1 chloride channel in tumor progression and provide insights into oncogenic signaling in human cancers with 11q13 amplification, thereby establishing ANO1 as a promising target for therapy in these highly prevalent tumor types.

ETD001: A novel inhaled ENaC blocker with an extended duration of action in vivo.

BACKGROUND: Inhibiting ENaC in the airways of people with cystic fibrosis (pwCF) is hypothesized to enhance mucociliary clearance (MCC) and provide clinical benefit. Historically, inhaled ENaC blockers have failed to show benefit in pwCF challenging this hypothesis. It is however unknown whether the clinical doses were sufficient to provide the required long duration of action in the lungs and questions whether a novel candidate could offer advantages where others have failed? METHODS: Dose-responses with the failed ENaC blockers (VX-371, BI 1265162, AZD5634, QBW276) together with ETD001 (a novel long acting inhaled ENaC blocker) were established in a sheep model of MCC and were used to predict clinically relevant doses that would provide a long-lasting enhancement of MCC in pwCF. In each case, dose predictions were compared with the selected clinical dose. RESULTS: Each of the failed candidates enhanced MCC in the sheep model. Translating these dose-response data to human equivalent doses, predicted that substantially larger doses of each candidate, than were evaluated in clinical studies, would likely have been required to achieve a prolonged enhancement of MCC in pwCF. In contrast, ETD001 displayed a long duration of action (≥16 h) at a dose level that was well tolerated in Phase 1 clinical studies. CONCLUSIONS: These data support that the ENaC blocker hypothesis is yet to be appropriately tested in pwCF. ETD001 has a profile that enables dosing at a level sufficient to provide a long duration of action in a Phase 2 clinical study in pwCF scheduled for 2024.

Niclosamide does not modulate airway epithelial function through blocking of the calcium activated chloride channel, TMEM16A.

Niclosamide and benzbromarone have been described as inhibitors of the calcium activated chloride channel, TMEM16A, and on this basis have been considered and tested as clinical candidates for the treatment of airway diseases. However, both compounds have previously demonstrated activity on a range of additional biological targets and it is unclear from the literature to what extent any activity on TMEM16A may contribute to efficacy in these models of airway disease. The aim of the present study was therefore to examine the pharmacology and selectivity of these clinical candidates together with a structurally unrelated TMEM16A blocker, Ani9, in a range of functional assays to better appreciate the putative role of TMEM16A in the regulation of both epithelial ion transport and the development of an airway epithelial mucus secretory phenoptype. Benzbromarone and Ani9 both attenuated recombinant TMEM16A activity in patch clamp studies, whereas in contrast, niclosamide induced a paradoxical potentiation of the TMEM16A-mediated current. Niclosamide and benzbromarone were also demonstrated to attenuate receptor-dependent increases in intracellular Ca2+ levels ([Ca2+]i) which likely contributed to their concomitant attenuation of the Ca2+-stimulated short-circuit current responses of FRT-TMEM16A and primary human bronchial epithelial (HBE) cells. In contrast, Ani9 attenuated the Ca2+-stimulated short-circuit current responses of both cell systems without influencing [Ca2+]i which supports a true channel blocking mechanism for this compound. Additional studies using HBE cells revealed effects of both niclosamide and benzbromarone on global ion transport processes (absorptive and secretory) as well as signs of toxicity (elevated LDH levels, loss of transepithelial resistance) that were not shared by Ani9. Ani9 also failed to influence the IL-13 induced differentiation of HBE towards a goblet cell rich, mucus hypersecreting epithelium, whereas niclosamide and benzbromarone attenuated numbers of both goblet and multiciliated cells, that would be consistent with cellular toxicity. Together these data challenge the description of niclosamide as a TMEM16A blocker and illustrate a range of off-target effects of both niclosamide and benzbromarone which may contribute to the reported activity in models of airway function.

Potentiating TMEM16A does not stimulate airway mucus secretion or bronchial and pulmonary arterial smooth muscle contraction.

The calcium-activated chloride channel (CaCC) TMEM16A enables chloride secretion across several transporting epithelia, including in the airways. Additional roles for TMEM16A have been proposed, which include regulating mucus production and secretion and stimulating smooth muscle contraction. The aim of the present study was to test whether the pharmacological regulation of TMEM16A channel function, could affect any of these proposed biological roles in the airways. In vitro, neither a potent and selective TMEM16A potentiator (ETX001) nor the potent TMEM16A inhibitor (Ani9) influenced either baseline mucin release or goblet cell numbers in well-differentiated primary human bronchial epithelial (HBE) cells. In vivo, a TMEM16A potentiator was without effect on goblet cell emptying in an IL-13 stimulated goblet cell metaplasia model. Using freshly isolated human bronchi and pulmonary arteries, neither ETX001 or Ani9 had any effect on the contractile or relaxant responses of the tissues. In vivo, ETX001 also failed to influence either lung or cardiovascular function when delivered directly into the airways of telemetered rats. Together, these studies do not support a role for TMEM16A in the regulation of goblet cell numbers or baseline mucin release, or on the regulation of airway or pulmonary artery smooth muscle contraction.

Protocol for a cluster randomised controlled trial evaluating a parenting with home visitation programme to prevent physical and emotional abuse of children in Indonesia: the Families First Programme.

INTRODUCTION: Every year, up to 1 billion children are victims of violence worldwide. Most child abuse takes place in the context of punishment. The Families First Programme, an adaptation of the Positive Discipline in Everyday Parenting Programme to the West Java context, is a parenting support programme anchored on children's rights that gives parents guidance on child development, parenting and positive discipline practices. This trial will evaluate the effectiveness of the Families First Programme compared with a waitlist control group. METHODS AND ANALYSIS: This is a pragmatic, parallel-group, stratified, cluster-randomised controlled trial. Twenty rural and urban villages in the Cianjur District, Indonesia, involving 720 caregivers of children up to 7 years of age, will be randomised. Villages will receive either a parenting programme consisting of 10 group sessions and four home visits over 3 months and standard community health and social services or just the latter. After completion of the trial period, the programme will be offered to those in the delayed group. Outcome data will be collected before randomisation (baseline), immediately postintervention (3 months postrandomisation) and 6 months later (9 months postrandomisation). The primary outcome will be frequency of physical and emotional punishment as measured by a weighted sum from three self-report items. Primary outcome analysis will use Poisson regression with generalised estimating equations and assess the interaction between intervention and time over baseline and 3 and 9 months postrandomisation assessments. Concurrent process evaluation will be conducted to assess programme satisfaction and facilitators and barriers to the implementation of the programme generalisable to other settings. ETHICS AND DISSEMINATION: Ethics approval was obtained from McGill University and Universitas Katolik Indonesia Atma Jaya. Results will be published in peer-reviewed journals and presented at scientific conferences and events for decision-makers, including in the participating communities. TRIAL REGISTRATION NUMBER: NCT03374761.

More than support to court: Rape victims and specialist sexual violence services.

This article explores the involvement of specialist sexual violence services, including Independent Sexual Violence Advisers (ISVAs), in supporting victims/survivors of rape and sexual abuse to engage with the criminal justice system (CJS) in England and Wales. The underpinning research, conducted in one area of England, included referral data from the police and key specialist sexual violence services, interviews with 15 victims/survivors of sexual violence in contact with the police and specialist services, and interviews with 14 practitioners from sexual violence and related services. We examine the complex needs of victims/survivors of sexual violence (who have experienced historical child sexual abuse, acquaintance rape or rape in the context of intimate partner abuse), how their needs differ and vary over time, and the ways in which these diverse and changing needs are met by specialist sexual violence services. Non-specialist agencies, such as statutory mental health services, are unable to provide similarly targeted responses. The research found that specialist sexual violence services play particularly crucial roles through the use of approaches that can be characterised as flexible, enabling, holding and mending. However, this important work could easily be lost in the current climate of local service commissioning, to the great detriment of victims/survivors of sexual violence.

Hypothalamic growth hormone-releasing hormone (GHRH) deficiency: targeted ablation of GHRH neurons in mice using a viral ion channel transgene.

Animal and clinical models of GHRH excess suggest that GHRH provides an important trophic drive to pituitary somatotrophs. We have adopted a novel approach to silence or ablate GHRH neurons, using a modified H37A variant of the influenza virus M2 protein ((H37A)M2). In mammalian cells, (H37A)M2 forms a high conductance monovalent cation channel that can be blocked by the antiviral drug rimantadine. Transgenic mice with (H37A)M2 expression targeted to GHRH neurons developed postweaning dwarfism with hypothalamic GHRH transcripts detectable by RT-PCR but not by in situ hybridization and immunocytochemistry, suggesting that expression of (H37A)M2 had silenced or ablated virtually all the GHRH cells. GHRH-M2 mice showed marked anterior pituitary hypoplasia with GH deficiency, although GH cells were still present. GHRH-M2 mice were also deficient in prolactin but not TSH. Acute iv injections of GHRH in GHRH-M2 mice elicited a significant GH response, whereas injections of GHRP-6 did not. Twice daily injections of GHRH (100 microg/d) for 7 d in GHRH-M2 mice doubled their pituitary GH but not PRL contents. Rimantadine treatment failed to restore growth or pituitary GH contents. Our results show the importance of GHRH neurons for GH and prolactin production and normal growth.

Family structure and sexual and reproductive health outcomes among adolescents in rural Sierra Leone.

Orphanhood is common in sub-Saharan Africa, and is a critical issue shaping global assistance for children. Care arrangements for children are often fluid, and many 'orphaned' children have a surviving biological parent. This study examines the protective effects of family-level factors on early sex and pregnancy in rural Sierra Leone. A survey of 530 adolescents in 2 districts in Sierra Leone was analysed to evaluate associations between living arrangement and orphanhood on recent sexual activity and pregnancies out of wedlock. After controlling for confounders, living with one's mother (AOR = 0.46, 95% CI: 0.22-1.00) and living with both parents (AOR = 0.36, 95% CI: 0.17-0.73) were protective against recent sexual activity. Orphan status was not significantly associated with recent sexual activity. Among 164 sexually active adolescents, neither living arrangement nor orphanhood was associated with pregnancy. This study demonstrates the protective effect of living with a surviving biological parent to delay early sexual debut. Once an adolescent becomes sexually active; however, living arrangement is not associated with the risk of pregnancy out of wedlock. The findings suggest that supporting family connectedness and preventing unnecessary family separation may benefit at least some aspects of adolescent sexual and reproductive health in Sierra Leone.

The discovery and characterization of a proton-gated sodium current in rat retinal ganglion cells.

The conduction of acid-evoked currents in central and sensory neurons is now primarily attributed to a family of proteins called acid-sensing ion channels (ASICs). In peripheral neurons, their physiological function has been linked to nociception, mechanoreception, and taste transduction; however, their role in the CNS remains unclear. This study describes the discovery of a proton-gated current in rat retinal ganglion cells termed I(Na(H+)), which also appears to be mediated by ASICs. RT-PCR confirmed the presence of ASIC mRNA (subunits la, 2a, 2b, 3, and 4) in the rat retina. Electrophysiological investigation showed that all retinal ganglion cells respond to rapid extracellular acidification with the activation of a transient Na+ current, the size of which increases with increasing acidification between pH 6.5 and pH 3.0. I(Na(H+)) desensitizes completely in the continued presence of acid, its current-voltage relationship is linear and its reversal potential shifts with E(Na). I(Na(H+)) is reversibly inhibited by amiloride (IC(50), 188 microm) but is resistant to block by TTX (0.5 microm), Cd2+ (100 microm), procaine (10 mm), and is not activated by capsaicin (0.5 microm). I(Na(H+)) is not potentiated by Zn2+ (300 microm) or Phe-Met-Arg-Phe-amide (50microm) but is inhibited by neuropeptide-FF (50microm). Acute application of pH 6.5 to retinal ganglion cells causes sustained depolarization and repetitive firing similar to the trains of action potentials normally associated with current injection into these cells. The presence of a proton-gated current in the neural retina suggests that ASICs may have a more diverse role in the CNS.

The rat retinal ganglion cell in culture: an accessible CNS neurone.

Retinal ganglion cells are vital for vision, some have intrinsic light sensing properties and in retinal networks display complex computational abilities. Furthermore they are implicated in a very common form of blindness, glaucoma as well some the symptoms of AIDS. Retinal ganglion cells, unlike many neurones of the central nervous system, have a clearly defined physiological role and can be identified in primary cultures with ease. Here we detail the cell culture and electrophysiological methods required to obtain recordings on the voltage-gated and ligand-gated ion currents and channels expressed by these neurones. Information is given on the range of non-ionotropic receptors that are thought to be present on these cells and what role they may have as model systems in the pharmacological and pharmaceutical research environment.