TMEM16A Antagonism: Therapeutic Potential with Desensitization of β-agonist Responsiveness in Asthma.

The efficacy of β-agonists in asthma is severely limited by β-adrenoceptor desensitization which results in poorly managed symptoms and refractory bronchoconstriction. Thus, there is a need to identify novel therapeutic pathways and to clarify the relationship between novel therapeutics and functional β-adrenoceptor responsiveness. We have previously demonstrated that acute antagonism of the calcium activated chloride channel, transmembrane member 16A (TMEM16A), relaxes airway smooth muscle (ASM).

Contribution of -labeled cells to alveolar regeneration is independent of tuft cells.

Viral infection often causes severe damage to the lungs, leading to the appearance of ectopic basal cells (EBCs) and tuft cells in the lung parenchyma. Thus far, the roles of these ectopic epithelial cells in alveolar regeneration remain controversial. Here, we confirm that the ectopic tuft cells are originated from EBCs in mouse models and COVID-19 lungs.

Anoctamin 1 antagonism potentiates conventional tocolytic-mediated relaxation of pregnant human uterine smooth muscle.

Background: Currently available tocolytic agents are not effective treatment for preterm labor beyond 48 h. A major reason is the development of maternal side effects which preclude the maintenance of an effective steady-state drug concentration. One strategy that can mitigate these side effects is utilizing synergistic drug combinations to reduce the drug concentrations necessary to elicit a clinical effect.

Ginger and its bioactive component 6-shogaol mitigate lung inflammation in a murine asthma model.

Asthma, a common disorder associated with airway inflammation and hyperresponsiveness, remains a significant clinical burden in need of novel therapeutic strategies. Patients are increasingly seeking complementary and alternative medicine approaches to control their symptoms, including the use of natural products. Ginger, a natural product that we previously demonstrated acutely relaxes airway smooth muscle (ASM), has long been reported to possess anti-inflammatory properties, although a precise mechanistic understanding is lacking.

Agonism of the TMEM16A calcium-activated chloride channel modulates airway smooth muscle tone.

TMEM16A (anoctamin 1) is an important calcium-activated chloride channel in airway smooth muscle (ASM). We have previously shown that TMEM16A antagonists such as benzbromarone relax ASM and have proposed TMEM16A antagonists as novel therapies for asthma treatment. However, TMEM16A is also expressed on airway epithelium, and TMEM16A agonists are being investigated as novel therapies for cystic fibrosis.

Generation of functional lungs via conditional blastocyst complementation using pluripotent stem cells.

Millions of people worldwide with incurable end-stage lung disease die because of inadequate treatment options and limited availability of donor organs for lung transplantation. Current bioengineering strategies to regenerate the lung have not been able to replicate its extraordinary cellular diversity and complex three-dimensional arrangement, which are indispensable for life-sustaining gas exchange. Here we report the successful generation of functional lungs in mice through a conditional blastocyst complementation (CBC) approach that vacates a specific niche in chimeric hosts and allows for initiation of organogenesis by donor mouse pluripotent stem cells (PSCs).

A novel GABA receptor ligand MIDD0301 with limited blood-brain barrier penetration relaxes airway smooth muscle ex vivo and in vivo.

Airway smooth muscle (ASM) cells express GABA A receptors (GABARs), and previous reports have demonstrated that GABAR activators relax ASM. However, given the activity of GABARs in central nervous system inhibitory neurotransmission, concern exists that these activators may lead to undesirable sedation. MIDD0301 is a novel imidazobenzodiazepine and positive allosteric modulator of the GABAR with limited brain distribution, thus eliminating the potential for sedation.

Functional comparison of anoctamin 1 antagonists on human uterine smooth muscle contractility and excitability.

Background: Pre-term birth is a major health care challenge throughout the world, and preterm labor represents a potentially reversible component of this problem. Current tocolytics do not improve preterm labor beyond 48 h. We have previously shown that anoctamin 1 (ANO1) channel blockade results in relaxation of pre-contracted human uterine smooth muscle (USM).

The dopamine D receptor is expressed and induces CREB phosphorylation and MUC5AC expression in human airway epithelium.

Background: Dopamine receptors comprise two subgroups, Gs protein-coupled “D1-like” receptors (D1, D5) and Gicoupled “D2-like” receptors (D2, D3, D4). In airways, both dopamine D1 and D2 receptors are expressed on airway smooth muscle and regulate airway smooth muscle force. However, functional expression of the dopamine D1 receptor has never been identified on airway epithelium.

Anoctamin Channels in Human Myometrium: A Novel Target for Tocolysis.

Background: Spontaneous preterm labor leading to preterm birth is a significant obstetric problem leading to neonatal morbidity and mortality. Current tocolytics are not completely effective and novel targets may afford a therapeutic benefit.

Objective: To determine whether the anoctamin (ANO) family, including the calcium-activated chloride channel ANO1, is present in pregnant human uterine smooth muscle (USM) and whether pharmacological and genetic modulation of ANO1 modulates USM contraction.

GABA receptor α-subunit knockout enhances lung inflammation and airway reactivity in a murine asthma model.

Emerging evidence indicates that hypnotic anesthetics affect immune function. Many anesthetics potentiate γ-aminobutyric acid A receptor (GABAR) activation, and these receptors are expressed on multiple subtypes of immune cells, providing a potential mechanistic link. Like immune cells, airway smooth muscle (ASM) cells also express GABARs, particularly isoforms containing α-subunits, and activation of these receptors leads to ASM relaxation.

Impaired Relaxation of Airway Smooth Muscle in Mice Lacking the Actin-Binding Protein Gelsolin.

Diverse classes of ligands have recently been discovered that relax airway smooth muscle (ASM) despite a transient increase in intracellular calcium concentrations ([Ca]). However, the cellular mechanisms are not well understood. Gelsolin is a calcium-activated actin-severing and -capping protein found in many cell types, including ASM cells.

Airway Epithelial Cell Release of GABA is Regulated by Protein Kinase A.

Introduction: γ-amino butyric acid (GABA) is not only the major inhibitory neurotransmitter in the central nervous system (CNS), but it also plays an important role in the lung, mediating airway smooth muscle relaxation and mucus production. As kinases such as protein kinase A (PKA) are known to regulate the release and reuptake of GABA in the CNS by GABA transporters, we hypothesized that β-agonists would affect GABA release from airway epithelial cells through activation of PKA.

Methods: C57/BL6 mice received a pretreatment of a β-agonist or vehicle (PBS), followed by methacholine or PBS.

Attenuation of airway smooth muscle contractility via flavonol-mediated inhibition of phospholipase-Cβ.

Enhanced contractility of airway smooth muscle (ASM) is a major pathophysiological characteristic of asthma. Expanding the therapeutic armamentarium beyond β-agonists that target ASM hypercontractility would substantially improve treatment options. Recent studies have identified naturally occurring phytochemicals as candidates for acute ASM relaxation.

Antagonists of the TMEM16A calcium-activated chloride channel modulate airway smooth muscle tone and intracellular calcium.

Background: Perioperative bronchospasm refractory to β agonists continues to challenge anesthesiologists and intensivists. The TMEM16A calcium-activated chloride channel modulates airway smooth muscle (ASM) contraction. The authors hypothesized that TMEM16A antagonists would relax ASM contraction by modulating membrane potential and calcium flux.

Calcium-activated chloride channels anoctamin 1 and 2 promote murine uterine smooth muscle contractility.

Objective: To determine the presence of calcium activated chloride channels anoctamin 1 (ANO1) and 2 (ANO2) in human and murine uterine smooth muscle (MUSM) and evaluate the physiologic role for these ion channels in murine myometrial contractility.

Study Design: We performed reverse transcription polymerase chain reaction to determine whether ANO1 and 2 are expressed in human and murine uterine tissue to validate the study of this protein in mouse models. Immunohistochemical staining of ANO1 and 2 was then performed to determine protein expression in murine myometrial tissue.

Chloride channel blockade relaxes airway smooth muscle and potentiates relaxation by β-agonists.

Severe bronchospasm refractory to β-agonists continues to cause significant morbidity and mortality in asthmatic patients. We questioned whether chloride channels/transporters are novel targets for the relaxation of airway smooth muscle (ASM). We have screened a library of compounds, derivatives of anthranilic and indanyloxyacetic acid, that were originally developed to antagonize chloride channels in the kidney.

Functional expression of the TMEM16 family of calcium-activated chloride channels in airway smooth muscle.

Airway smooth muscle hyperresponsiveness is a key component in the pathophysiology of asthma. Although calcium-activated chloride channel (CaCC) flux has been described in many cell types, including human airway smooth muscle (HASM), the true molecular identity of the channels responsible for this chloride conductance remains controversial. Recently, a new family of proteins thought to represent the true CaCCs was identified as the TMEM16 family.

Tumor necrosis factor-alpha prevents desensitization of Galphas-coupled receptors by regulating GRK2 association with the plasma membrane.

We have reported previously that interleukin-1 and tumor necrosis factor (TNF)-alpha increase expression and function of adenosine A2A receptors (A2ARs), although the increased function is disproportionate to the increment in expression. We therefore studied the effect of TNF-alpha on A2A R function and desensitization in human monocytoid THP-1 cells. We observed that TNF-alpha regulates activity of A2A Rs and other G protein-coupled receptors (GPCRs) by altering their ligand-mediated desensitization.

Upregulation of placental growth factor by vascular endothelial growth factor via a post-transcriptional mechanism.

Vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are key angiogenic stimulators during normal development and wound healing, as well as in a variety of pathological conditions. Recent studies have demonstrated a synergistic effect of VEGF and PlGF in pathological angiogenesis and suggest a role for PlGF in amplifying VEGF action in endothelial cells. We show here in the mouse model of oxygen-induced retinopathy that VEGF is significantly increased (P<0.