Neuroinflammatory Consequences of Rhinovirus Infection in Human Epithelial and Neuronal Models.

Introduction: Rhinovirus (RV) is the leading cause of exacerbations of lung disease. A sensory neuronal model, derived from human dental pulp stem cells and differentiated into peripheral neuronal equivalents (PNEs), was used to examine RV's effects on airway sensory nerves. We investigated whether RV can directly infect and alter PNEs or whether it exerts effects indirectly via the release of mediators from infected epithelial cells.

Distinct domains of LINGO1 control surface expression and biophysical properties of large conductance Ca- and voltage-activated potassium (BK) channels.

Large conductance Ca and voltage-activated K (BK) channels are ubiquitous ion channels that regulate a wide array of physiological process. Their functional diversity can be modulated by accessory proteins including a family of leucine-rich repeat and immunoglobulin-like domain-containing protein (LINGO) subunits that may control both the biophysical properties and surface trafficking of BK channels. By exploiting differences in the regulation of BK channels by LINGO1 and LINGO2 subunits we have taken a chimeric approach to dissect the role of distinct domains of these single transmembrane pass proteins.

Unravelling the Role of Post-Junctional M2 Muscarinic Receptors in Cholinergic Nerve-Mediated Contractions of Airway Smooth Muscle.

It has long been recognised that airway smooth muscle cells (ASMCs) possess an abundance of M2 muscarinic receptors (M2Rs). However, the contribution of postjunctional M2Rs to contractions of airway smooth muscle (ASM) induced by the release of acetylcholine (ACh) from parasympathetic nerves was thought to be minimal. Instead, it was believed that these responses were exclusively mediated by activation of M3Rs.

ANO1 channels are expressed in mouse urethral smooth muscle but do not contribute to agonist or neurally evoked contractions.

Anoctamin-1 Ca-activated Cl channels (ANO1) are proposed to modulate contractility of urethra smooth muscle cells (USMC), but their cellular expression and contribution to agonist/neural evoked activity is unclear. ANO1 is implicated as a potential target to treat incontinence, thus this is an important issue to resolve. We sought to clarify roles of ANO1 in contractility of mouse USMC.

K7 channels modulate tension and calcium signaling in mouse corpus cavernosum.

Adrenergic stimulation induces contractions in the corpus cavernosum smooth muscle (CCSM), which are important in maintaining penile flaccidity. The aim of this study was to investigate the role of K7 channels in regulating contractions and their underlying Ca signals in mouse CCSM. Quantitative PCR revealed transcriptional expression of and genes in the whole CCSM, with as the most highly transcribed K7-encoding gene.

Role of voltage-gated Ca channels and Ano1 Ca-activated Cl channels in M2 muscarinic receptor-dependent contractions of murine airway smooth muscle.

Cholinergic tone is elevated in obstructive lung conditions such as chronic obstructive pulmonary disease (COPD) and asthma, but the cellular mechanisms underlying cholinergic contractions of airway smooth muscle (ASM) are still unclear. Some studies report an important role for L-type Ca channels (LTCC) and Ano1 Ca-activated Cl channels (CACC) in these responses, but others dispute their importance. Cholinergic contractions of ASM involve activation of M3Rs, however, stimulation of M2Rs exerts a profound hypersensitization of these responses.

Evidence of an excitatory purinergic innervation in mouse corpus cavernosum smooth muscle.

Background: Evidence suggests that the corpus cavernosum smooth muscle (CCSM) cells of several species, including humans, express purinergic P2X receptors, but it is not known if the corpus cavernosum has an excitatory purinergic innervation.

Aim: In this study we aimed to determine if the mouse CCSM has a functional purinergic innervation.

Methods: Mouse CCSM myocytes were enzymatically isolated and studied using the perforated patch configuration of the patch clamp technique.

Interstitial cell of Cajal-like cells (ICC-LC) exhibit dynamic spontaneous activity but are not functionally innervated in mouse urethra.

Urethral smooth muscle cells (USMC) contract to occlude the internal urethral sphincter during bladder filling. Interstitial cells also exist in urethral smooth muscles and are hypothesized to influence USMC behaviours and neural responses. These cells are similar to Kit interstitial cells of Cajal (ICC), which are gastrointestinal pacemakers and neuroeffectors.

TRPV2 modulates mechanically Induced ATP Release from Human bronchial epithelial cells.

Repetitive bouts of coughing expose the large airways to significant cycles of shear stress. This leads to the release of alarmins and the tussive agent adenosine triphosphate (ATP) which may be modulated by the activity of ion channels present in the human airway. This study aimed to investigate the role of the transient receptor potential subfamily vanilloid member 2 (TRPV2) channel in mechanically induced ATP release from primary bronchial epithelial cells (PBECs).

Regulation of nerve-evoked contractions of the murine vas deferens.

Stimulation of sympathetic nerves in the vas deferens yields biphasic contractions consisting of a rapid transient component resulting from activation of P2X1 receptors by ATP and a secondary sustained component mediated by activation of α-adrenoceptors by noradrenaline. Noradrenaline can also potentiate the ATP-dependent contractions of the vas deferens, but the mechanisms underlying this effect are unclear. The purpose of the present study was to investigate the mechanisms underlying potentiation of transient contractions of the vas deferens induced by activation of α-adrenoceptors.

House dust mite allergens induce Ca signalling and alarmin responses in asthma airway epithelial cells.

Type 2 inflammation in asthma develops with exposure to stimuli to include inhaled allergens from house dust mites (HDM). Features include mucus hypersecretion and the formation of pro-secretory ion transport characterised by elevated basal Cl current. Studies using human sinonasal epithelial cells treated with HDM extract report a higher protease activated receptor-2 (PAR-2) agonist-induced calcium mobilisation that may be related to airway sensitisation by allergen-associated proteases.

Modulation of fast sodium current in airway smooth muscle cells by exchange protein directly activated by cAMP.

Airway smooth muscle (ASM) cells from mouse bronchus express a fast sodium current mediated by Na1.7. We present evidence that this current is regulated by cAMP.

Blockade of Kv7 channels reverses the inhibitory effects of exchange protein directly activated by cAMP activation on purinergic contractions of the murine detrusor.

Purinergic contractions of the detrusor are reduced by cAMP, but the underlying mechanisms are unclear. We examined the effects of BK and Kv7 channel modulators on purinergic contractions of the detrusor and tested if the inhibitory effects of activators of the cAMP effectors, PKA and EPAC, were reduced by blockade of BK or Kv7 channels. Purinergic contractions of the murine detrusor were induced by electric field stimulation (EFS) or application of the P2X receptor agonist α,β-MeATP.

The TMEM16A blockers benzbromarone and MONNA cause intracellular Ca-release in mouse bronchial smooth muscle cells.

We investigated effects of TMEM16A blockers benzbromarone, MONNA, CaCCA01 and Ani9 on isometric contractions in mouse bronchial rings and on intracellular calcium in isolated bronchial myocytes. Separate concentrations of carbachol (0.1-10 μM) were applied for 10 min periods to bronchial rings, producing concentration-dependent contractions that were well maintained throughout each application period.

Oxidation modulates LINGO2-induced inactivation of large conductance, Ca-activated potassium channels.

Ca and voltage-activated K (BK) channels are ubiquitous ion channels that can be modulated by accessory proteins, including β, γ, and LINGO1 BK subunits. In this study, we utilized a combination of site-directed mutagenesis, patch clamp electrophysiology, and molecular modeling to investigate if the biophysical properties of BK currents were affected by coexpression of LINGO2 and to examine how they are regulated by oxidation. We demonstrate that LINGO2 is a regulator of BK channels, since its coexpression with BK channels yields rapid inactivating currents, the activation of which is shifted ∼-30 mV compared to that of BKα currents.

Ca -activated Cl channels (TMEM16A) underlie spontaneous electrical activity in isolated mouse corpus cavernosum smooth muscle cells.

Penile detumescence is maintained by tonic contraction of corpus cavernosum smooth muscle cells (CCSMC), but the underlying mechanisms have not been fully elucidated. The purpose of this study was to characterize the mechanisms underlying activation of TMEM16A Ca -activated Cl channels in freshly isolated murine CCSMC. Male C57BL/6 mice aged 10-18 weeks were euthanized via intraperitoneal injection of sodium pentobarbital (100 mg.

Functional expression of Na1.7 channels in freshly dispersed mouse bronchial smooth muscle cells.

Isolated smooth muscle cells (SMCs) from mouse bronchus were studied using the whole cell patch-clamp technique at ∼21°C. Stepping from -100 mV to -20 mV evoked inward currents of mean amplitude -275 pA. These inactivated (tau = 1.

Contribution of Postjunctional M2 Muscarinic Receptors to Cholinergic Nerve-Mediated Contractions of Murine Airway Smooth Muscle.

Postjunctional M2Rs on airway smooth muscle (ASM) outnumber M3Rs by a ratio of 4:1 in most species, however, it is the M3Rs that are thought to mediate the bronchoconstrictor effects of acetylcholine. In this study, we describe a novel and profound M2R-mediated hypersensitization of M3R-dependent contractions of ASM at low stimulus frequencies..

Modulation of carbachol-induced Ca oscillations in airway smooth muscle cells by PGE.

PGE is a potent bronchodilator, but the mechanisms underlying this effect have not been fully elucidated. Acetylcholine-induced contractions of airway smooth muscle (ASM) are associated with the generation of repetitive Ca oscillations in airway smooth muscle cells (ASMC) and the force of contraction is positively correlated with the frequency of the underlying Ca oscillations. The purpose of the present study was to examine if carbachol-evoked Ca oscillations in isolated ASMC were inhibited by PGE.

Fast voltage-dependent sodium (Na ) currents are functionally expressed in mouse corpus cavernosum smooth muscle cells.

Background And Purpose: Corpus cavernosum smooth muscle (CCSM) exhibits phasic contractions that are coordinated by ion channels. Mouse models are commonly used to study erectile dysfunction, but there are few published electrophysiological studies of mouse CCSM. We describe the voltage-dependent sodium (Na ) currents in mouse CCSM and investigate their function.

Regulation of P2X1 receptors by modulators of the cAMP effectors PKA and EPAC.

P2X1 receptors are adenosine triphosphate (ATP)-gated cation channels that are functionally important for male fertility, bladder contraction, and platelet aggregation. The activity of P2X1 receptors is modulated by lipids and intracellular messengers such as cAMP, which can stimulate protein kinase A (PKA). Exchange protein activated by cAMP (EPAC) is another cAMP effector; however, its effect on P2X1 receptors has not yet been determined.

Calcium-Activated K Channels (K) and Therapeutic Implications.

Potassium channels are the most diverse and ubiquitous family of ion channels found in cells. The Ca and voltage gated members form a subfamily that play a variety of roles in both excitable and non-excitable cells and are further classified on the basis of their single channel conductance to form the small conductance (SK), intermediate conductance (IK) and big conductance (BK) K channels.In this chapter, we will focus on the mechanisms underlying the gating of BK channels, whose function is modified in different tissues by different splice variants as well as the expanding array of regulatory accessory subunits including β, γ and LINGO subunits.

Role of Ano1 Ca-activated Cl channels in generating urethral tone.

Urinary continence is maintained in the lower urinary tract by the contracture of urethral sphincters, including smooth muscle of the internal urethral sphincter. These contractions occlude the urethral lumen, preventing urine leakage from the bladder to the exterior. Over the past 20 years, research on the ionic conductances that contribute to urethral smooth muscle contractility has greatly accelerated.