Smooth Muscle Contractile Activity Research Articles

3D Airway Epithelial-Fibroblast Biomimetic Microfluidic Platform to Unravel Engineered Nanoparticle-Induced Acute Stress Responses as Exposome Determinants.

Insights into how biological systems respond to high- and low-dose acute environmental stressors are a fundamental aspect of exposome research. However, studying the impact of low-level environmental exposure in conventional in vitro settings is challenging. This study employed a three-dimensional (3D) biomimetic microfluidic lung-on-chip (μLOC) platform and RNA-sequencing to examine the effects of two model anthropogenic engineered nanoparticles (NPs): zinc oxide nanoparticles (Nano-ZnO) and copier center nanoparticles (Nano-CCP). The airway epithelium exposed to these NPs exhibited dose-dependent increases in cytotoxicity and barrier dysregulation (dominance of the external exposome). Interestingly, even nontoxic and low-level exposure (10 μg/mL) of the epithelium compartment to Nano-ZnO triggered chemotaxis of lung fibroblasts toward the epithelium. An increase in α smooth muscle actin (α-SMA) expression and contractile activity was also observed in these cells, indicating a bystander-like adaptive response (dominance of internal exposome). Further bioinformatics and network analysis showed that a low-dose Nano-ZnO significantly induced a robust transcriptomic response and upregulated several hub genes associated with the development of lung fibrosis. We propose that Nano-ZnO, even at a no observable effect level (NOEL) dose according to conventional standards, can function as a potent nanostressor to disrupt airway epithelium homeostasis. This leads to a cascade of profibrotic events in a cross-tissue compartment fashion. Our findings offer new insights into the early acute events of respiratory harm associated with environmental NPs exposure, paving the way for better exposomic understanding of this emerging class of anthropogenic nanopollutants.

Анестетик лідокаїн пригнічує холінергічні скорочення тонкої кишки миші та спричиняє порушення шлунково-кишкового тракту людини

Lidocaine is one of the components of multimodal low-opioid anesthesia, which is commonly used in surgical procedures, especially in cardiac surgery. Lidocaine has been used in medicine for a long time as a local anesthetic, but after the invention of the method of its intravenous administration, questions arose about its possible side effects on the visceral system, in particular on the motility of the gastrointestinal tract. Therefore, the aim of our work was to investigate the main aspects of the use of lidocaine-based opioid-free anesthesia and its side effects and also to study the effect of lidocaine on the contractile activity of small intestine smooth muscle, namely the mouse ileum. We recorded the contractile activity of smooth muscles of the ileum of mice using the tensiometry method and found that lidocaine at the clinically relevant concentration range, i.e. 1.5, 3, and 5 μg/ml, inhibited carbachol-induced contractions by 16, 27 and 37%, respectively (n = 7). To determine the side effects of opioid-free anesthesia, we studied 60 patients with coronary artery disease undergoing coronary artery stenting with the administration of anesthesia based on lidocaine solution at different concentrations (1 and 2 mg/kg). The side effects included nausea and vomiting, which may indicate а disturbance of gastrointestinal motility, as well as numbness of the limbs, cheeks, tongue, etc. These results contribute to a better understanding of the spectrum of action of lidocaine, a popular anesthetic in surgery, on the visceral system and become an important basis for the future development of new schemes for the use of local anesthetics in clinical practice, particularly in surgical procedures.

Platelet-activating factor (PAF) enhances guinea pig detrusor smooth muscle contractile activities by stimulating voltage-dependent Ca2+ channels and store-operated Ca2+ channels

We investigated the extracellular Ca2+ influx pathways involved in platelet-activating factor (PAF)-enhanced guinea pig detrusor smooth muscle (DSM) contractile activities. One micromolar PAF-enhanced DSM contractile activities were completely inhibited by extracellular Ca2+ removal and strongly suppressed by voltage-dependent Ca2+ channel (VDCC) inhibitors. PAF-enhanced DSM contractile activities remaining in the presence of verapamil (10 μM) were not inhibited by LOE-908 (30 μM, an inhibitor of receptor-operated Ca2+ channels (ROCCs)), but were almost completely inhibited by SKF-96365 (30 μM, an inhibitor of store-operated Ca2+ channels (SOCCs) and ROCCs). These results suggest that VDCCs and SOCCs are responsible for PAF-enhanced DSM contractile activities.

Пригнічувальна дія загального анестетика кетаміну на транзієнти внутрішньоклітинної концентрації іонів кальцію та скорочення гладеньком’язових клітин тонкої кишки миші

The mechanisms of the negative consequences of general anaesthetics action on the nervous system have been studied in detail, but regarding smooth muscle function, such issues have not yet been sufficiently addressed. In this study, we investigated the effect of the general intravenous anaesthetic ketamine on the level of intracellular calcium in isolated ileum myocytes and the contractile activity of smooth muscle strips of the mouse small intestine. The concentration of intracellular calcium in cells was measured using the Ca2+-sensitive fluorescent dye Fura-2, and tensiometry was used to record the contractile activity of smooth muscles. It was shown that ketamine at a concentration of 100 µM significantly, by 40%, suppressed carbachol-induced contractile reactions of the ileum. The inhibitory effect correlated with the suppression of the intracellular calcium responses to carbachol in isolated smooth muscle cells after the addition of ketamine to the extracellular solution, which was by 65% on average. These results contribute to our better understanding of the possible membrane and intracellular mechanisms of the development of post-surgical intestinal motility disorders.

The role of intracellular calcium and Rho kinase pathways in G protein-coupled receptor-mediated contractions of urinary bladder urothelium and lamina propria.

The influence of extracellular and intracellular calcium on smooth muscle contractile activity varies between organs. In response to G protein-coupled receptor (GPCR) stimulation, the urinary bladder detrusor muscle has shown a 70% dependence on extracellular calcium, whereas the urothelium and lamina propria (U&LP) has a 20%-50% dependence. However, as this only accounts for partial contractile activity, the contribution of intracellular calcium and calcium sensitization pathways remains unclear. This study assessed the role of intracellular signaling pathways on GPCR-mediated urinary bladder U&LP contraction. Porcine U&LP responses to activation of the Gq/11-coupled muscarinic, histamine, 5-hydroxytryptamine (serotonin), neurokinin, prostaglandin, and angiotensin II receptors were assessed with three selective inhibitors of store-released intracellular calcium, 2-aminoethyl diphenylborinate (2-APB), cyclopiazonic acid (CPA), and ruthenium red, and three Rho kinase inhibitors, fasudil, Y-27632, and GSK269962. There was no discernible impact on receptor agonist-induced contractions of the U&LP after blocking intracellular calcium pathways, suggesting that this tissue is more sensitive to alterations in the availability of extracellular calcium. However, an alternative mechanism of action for GPCR-mediated contraction was identified to be the activation of Rho kinase, such as when Y-27632 significantly reduced the GPCR-mediated contractile activity of the U&LP by approximately 50% (P < 0.05, n = 8). This suggests that contractile responses of the bladder U&LP do not involve a significant release of calcium from intracellular stores, but that Gq/11-coupled receptor activation causes calcium sensitization via Rho kinase. This study highlights a key role for Rho kinase in the urinary bladder, which may provide a novel target in the future pharmaceutical management of bladder contractile disorders.

Inhibition of uterine contractility by guanine-based purines in non-pregnant rats.

Growing evidence pointed out that guanine-based purines are able to modulate smooth muscle contractile activity of blood vessels and gastrointestinal tract. Since, so far, possible guanine-based purine modulation of uterine musculature is unknown, the aim of the present study was to investigate in vitro, using organ bath technique, guanosine and guanine effects on spontaneous uterine contraction, and uterine contraction induced by K+-depolarization and oxytocin in a non-pregnant rat. Guanosine, but not guanine, reduced the amplitude of spontaneous contraction of the uterine muscle in a dose-dependent manner. The inhibitory response was antagonized by S-(4-nitrobenzyl)-6-thioinosine (NBTI), a membrane nucleoside transporter inhibitor, but persisted in the presence of theophylline, a nonselective adenosine receptor antagonist, or propanolol, β1/β2 adrenoreceptor antagonist or blockers of a nitrergic pathway. In addition, potassium channel blockers did not influence guanosine-induced effects. Guanosine was able to inhibit the external calcium (Ca2+) influx-induced contraction, but it did not affect the contraction induced by high-KCl solution, indicating that guanosine does not interact with L-type voltage-gated calcium channel. Guanosine prevented/reduced uterine contractions induced by oxytocin, even in the absence of external calcium. In conclusion, guanosine is able to reduce both spontaneous and oxytocin-induced contractions of rat myometrium, likely subsequently to its intracellular intake. The blockade of extracellular Ca2+ influx and reduction of Ca2+ release from the intracellular store are the mechanisms involved in the guanosine-induced tocolytic effects.

Bioactive Metabolites from the Fruiting Body and Mycelia of Newly-Isolated Oyster Mushroom and Their Effect on Smooth Muscle Contractile Activity.

Higher basidiomycetes are recognized as functional foods due to their bioactive compound content, which exerts various beneficial effects on human health, and which have been used as sources for the development of natural medicines and nutraceuticals for centuries. The aim of this study was to evaluate and compare the biological potential of basidiocarp and mycelial biomass produced by submerged cultivation of a new regionally isolated oyster mushroom. The strain was identified with a high percentage of confidence (99.30%) as Pleurotus ostreatus and was deposited in the GenBank under accession number MW 996755. The β-glucan content in the basidiocarp and the obtained mycelial biomass was 31.66% and 12.04%, respectively. Three mycelial biomass and basidiocarp extracts were prepared, and the highest total polyphenol content (5.68 ± 0.15 mg GAE/g DW and 3.20 ± 0.04 mg GAE/g DW) was found in the water extract for both the fruiting body and the mycelium biomass. The in vitro antioxidant activity of the extracts was investigated, and it was determined that the water extracts exhibited the most potent radical scavenging activity. The potential ability of this new fungal isolate to affect the contractile activity (CA) of dissected smooth muscle preparations (SMP) was examined for the first time. It was found that oyster mushrooms likely exhibit indirect contractile effects on the gastric smooth muscle (SM) cells.

Endothelial Ion Channels and Cell-Cell Communication in the Microcirculation

Endothelial cells in resistance arteries, arterioles, and capillaries express a diverse array of ion channels that contribute to Cell-Cell communication in the microcirculation. Endothelial cells are tightly electrically coupled to their neighboring endothelial cells by gap junctions allowing ion channel-induced changes in membrane potential to be conducted for considerable distances along the endothelial cell tube that lines arterioles and forms capillaries. In addition, endothelial cells may be electrically coupled to overlying smooth muscle cells in arterioles and to pericytes in capillaries via heterocellular gap junctions allowing electrical signals generated by endothelial cell ion channels to be transmitted to overlying mural cells to affect smooth muscle or pericyte contractile activity. Arteriolar endothelial cells express inositol 1,4,5 trisphosphate receptors (IP3Rs) and transient receptor vanilloid family member 4 (TRPV4) channels that contribute to agonist-induced endothelial Ca2+ signals. These Ca2+ signals then activate intermediate and small conductance Ca2+-activated K+ (IKCa and SKCa) channels causing vasodilator-induced endothelial hyperpolarization. This hyperpolarization can be conducted along the endothelium via homocellular gap junctions and transmitted to overlying smooth muscle cells through heterocellular gap junctions to control the activity of voltage-gated Ca2+ channels and smooth muscle or pericyte contraction. The IKCa- and SKCa-induced hyperpolarization may be amplified by activation of inward rectifier K+ (KIR) channels. Endothelial cell IP3R- and TRPV4-mediated Ca2+ signals also control the production of endothelial cell vasodilator autacoids, such as NO, PGI2, and epoxides of arachidonic acid contributing to control of overlying vascular smooth muscle contractile activity. Cerebral capillary endothelial cells lack IKCa and SKCa but express KIR channels, IP3R, TRPV4, and other Ca2+ permeable channels allowing capillary-to-arteriole signaling via hyperpolarization and Ca2+. This allows parenchymal cell signals to be detected in capillaries and signaled to upstream arterioles to control blood flow to capillaries by active parenchymal cells. Thus, endothelial cell ion channels importantly participate in several forms of Cell-Cell communication in the microcirculation that contribute to microcirculatory function and homeostasis.

Абдомінальний больовий синдром у дітей та підлітків: можливості терапії

Біль у животі — частий привід для звернення пацієнтів різного віку до лікаря, одна з найбільш частих скарг, що пред’являються дітьми та їх батьками. Больовий абдомінальний синдром у дітей — це сукупність симптомів, що супроводжують різні хірургічні та нехірургічні захворювання, одним із проявів яких є біль у животі. Розрізняють гострий і хронічний (рецидивуючий) біль. Гострий біль у животі може бути проявом хірургічної патології, травми або гострого інфекційного захворювання. Біль у животі в більшості випадків обумовлений хронічними захворюваннями органів травлення або функціональними розладами. Педіатри, лікарі загальної практики та гастроентерологи частіше зустрічаються з рецидивуючим болем у животі (довготривалий переривчастий або постійний біль). Рецидивуючий біль у животі у дітей визначається як три епізоди болю, що відбуваються протягом трьох місяців і впливають на нормальну активність дитини. Погоджувальний документ Американської педіатричної асоціації та Північноамериканської асоціації дитячої гастроентерології, гепатології та харчування в 2005 році запропонував використовувати замість терміну «рецидивуючий біль у животі» термін «хронічний абдомінальний біль». Хронічний абдомінальний біль найчастіше (90–95 % випадків) вважається функціональним (неорганічним) болем у животі без об’єктивних ознак основного органічного розладу і характеризується різноманіттям проявів. За механізмом виникнення виокремлюють вісцеральний, парієтальний (соматичний), іррадиюючий та психогенний біль. При болі в животі необхідно оцінити: час появи, інтенсивність, характер, тривалість, локалізацію. На першому етапі діагностики необхідно виключити гостру хірургічну патологію. Про високу ймовірність хірургічної патології свідчать «симптоми тривоги». На наступному етапі проводиться диференційна діагностика органічних та функціональних причин абдомінального болю. При всіх видах функціонального болю відзначають порушення вісцеральної моторики і розвиток спазмів. Скорочувальна активність гладких м’язів ініціюється парасимпатичною нервовою системою. Лікування рецидивуючого болю в животі направлено на усунення його причин: зняття спазму, нормалізацію моторики шлунково-кишкового тракту. На даний час серед різних груп спазмолітиків при лікуванні функціональних розладів травного тракту віддають перевагу селективним міотропним спазмолітикам. Серед них мебеверин є оптимальним за ефективністю та безпекою. Мебеверин блокує швидкі натрієві канали, розташовані на клітинній мембрані міоцитів, перешкоджаючи надходженню іонів натрію в клітину. Цей механізм призводить до послаблення скорочувальної функції гладком’язового волокна і сприяє усуненню спазму, але не викликає гіпотонії. На відміну від антихолінергічних препаратів мебеверин справляє селективну дію на гладкі м’язи травного тракту. У клінічній практиці заслуговує на увагу мебеверину гідрохлорид — Спарк® (ПАТ «Фармак»), при прийомі якого відзначається збереження нормального тонусу і перистальтики після купірування м’язового спазму. Препарат Спарк® випускається в капсулах, одна капсула містить 200 мг мебеверину гідрохлориду. Згідно з інструкцією мебеверин (Спарк®) призначається дорослим і дітям від 10 років по 1 капсулі два рази на добу. Препарат не має системної дії. Застосування мебеверину (Спарк®) патогенетично обґрунтовано для лікування захворювань, що перебігають з абдомінальним больовим синдромом у дорослих і дітей старше 10 років.

Quercetin affects uterine smooth muscle contractile activity in gilts.

Quercetin is a polyphenolic flavonoid occurring in leaves, stems, flowers and fruits of many plants. In traditional Chinese medicine, it is used as a natural therapeutic agent with a broad spectrum of activities (antioxidant, neuroprotective, anti-inflammatory, anticancer, antibacterial and antiviral). Moreover, quercetin affects function of the reproductive tract, however the knowledge of this activity is still fragmentary. Therefore, this study aimed to determine the influence of quercetin on the contractile activity of the porcine myometrium collected from immature (n = 6), cyclic (n = 6) and early pregnant (n = 6) gilts. Strips of the myometrium (comprising longitudinal and circular layer) were resected from the middle part of the uterine horns and the isometric contractions were recorded. After 60–90 min of preincubation, the strips were stimulated with quercetin in increasing (10−13–10−1 M) concentrations and the changes in the tension amplitude and frequency of contractions were measured. Quercetin decreased (P<0.01–0.001) the amplitude of contractions at concentrations 10−11–10−1 M and 10−10–10−1 M in cyclic and early pregnant groups, respectively. The frequency of contractions decreased in all groups but was the highest (at concentrations 10−11–10−1 M; P<0.05–0.001) in the cyclic group and the lowest (at concentrations 10−5–10−1 M; P<0.01) in the immature group. The tension decreased only in the cyclic group after quercetin administration in high concentrations (10−6–10−1 M; P<0.05–0.01). The results indicate that quercetin causes relaxation of the porcine uterine smooth muscle but this activity is strongly related to the physiological status of the gilts.

Morphological changes of the myenteric plexus at different gut segments of human fetuses

ABSTRACT The neural crest cell-derived enteric nervous system (ENS) is the intrinsic innervation of the gastrointestinal tract (GIT) which consists of neurons and enteric glia cells in the myenteric ganglia and forming plexus. The ENS consists mainly of submucosal and myenteric plexuses. It has various functions on the GIT, which include control of local blood flow, motility, mucosal transport, secretions, immune modulation as well as endocrine functions and coordinated contractile activity of smooth muscle. The knowledge on the development of the innervations at different segments of the gut in humans from 11 to 26 weeks of gestation (WG) may help in understanding the pathophysiology of various congenital diseases affecting the ENS. The aim of this study is to determine the morphology of the myenteric plexus in the esophagus, ascending colon and sigmoid colon at various weeks of gestation. Tissue samples from 10 naturally terminated fetuses aged 11–26 WG were processed for hematoxylin and eosin staining and immunohistochemistry assay. The neurons, enteric glia, the smooth muscle were visualized using PGP9.5, Vimentin and S-100 antibodies. The number of neurons and enteric glial cells appeared lowest in the esophagus than the ascending and sigmoid colon. The myenteric ganglion was closely apposed to each other, forming a continuous arch along the entire circumference of gut sections of ascending and sigmoid colon but the myenteric ganglia in the esophagus was thinly populated and widely spread in the fetus at 13 WG. As the fetal gastrointestinal tract grew in diameter and length, the myenteric ganglia became discernible.

Влияние интерлейкинов на сокращения мышцы трахеи и бронхов крысы

The article considers the role of IL-1β, IL-4, IL-8 and IL-13 in contractile activity of smooth muscles of trachea and bronchi. Studies were conducted on isolated preparations with using of electrical stimulation of the postganglionic nerves (frequency – 30 stimules/s, duration – 0,5 ms, amplitude – 20 V, duration of stimulation – 10 s.). Two groups of animals were formed: a control group (received an intraperitoneal injection of saline solution) and an experimental group with bronchial asthma (received an intraperitoneal injection of ovalbumin with its repeated administration after 14 days). Further, the tracheal and bronchi muscle contraction was evaluated after repeated ovalbumin administration and after perfusion with interleukin solutions. The study found that IL-4, IL-8 and IL-13 lead to a large increase in contractile responses of the smooth muscle of the trachea and bronchi both in the control group of animals and in the group of animals with ovalbumin-induced bronchial asthma. IL-1β leads to a relaxation effect on the tracheal and bronchi muscle in conditions of physiological norm and pathology, which can be considered as a compensatory mechanism that supports the function of external respiration.

The Role of TRPV4 Cation Channels in Smooth Muscle Contractile Activity in Rats

Although it was shown that transient receptor potential channels are expressed in the intestinal and myometrial smooth muscle cells and can control gastrointestinal motility and regulate uterine contractility the specific role of transient receptor potential vanilloid-type 4 channel in smooth muscle cells contraction remain largely unknown. The purpose of the study was to test the action of transient receptor potential vanilloid-type 4 selective agonist GSK1016790A on smooth muscle cells contraction in rat’s colon with experimental Parkinson`s disease and in the pregnant rat uterus (18-22 days of gestation). Material and methods. The Parkinson’s disease was induced by single unilateral stereotaxic injection of 12 μg 6-OHDA. The percentage of destroyed dopaminergic neurons was evaluated in apomorphine test (0.5 mg/kg, i.p.) at 1 and 2 weeks after surgery. The water content in faeces was evaluated on the 1st day, then at the 3rd week and 7th month of the experiment. The daily volume of water consumption and gastrointestinal transit time were evaluated at the 3rd week and 7th month after surgery. The action of transient receptor potential vanilloid-type 4 agonist GSK1016790A (0.3 mmol) on smooth muscle cells of colon and myometrium strips contraction was estimated by isometric tension recording. Results and discussion. The apomorphine test showed a progressive increase in the number of turns between the 1st and 2nd week after inducing 6-OHDA-PD. The water content in faeces was increased at the 3rd week (P&lt;0.05) vs. 1st day of the experiment. The rats with 6-OHDA-PD drank less water vs. placebo and intact groups. We observed a 17% delayed GI transit time in 6-OHDA-PD rats (P&lt;0.01) vs. intact and 21% vs. sham-lesioned group of rats 3 weeks after the 6-OHDA treatment. 7 months after the surgery GI transit time was increased more than twice in all studied groups. Transient receptor potential vanilloid-type 4 agonist action on smooth muscle cells of 6-OHDA-PD rats was reduced by 21% compared to intact group and by 46% in sham-lesioned group (P&lt;0.05). After the application of GSK1016790A the rat myometrium strips a 28.4% (P&lt;0.05) decrease of the contractile force was recorded. It was accompanied by a 30.7% (P&lt;0.05) decline of the muscle work estimated as the area under the contractile curve. Suppression of the amplitude of uterine contraction was also followed by a 39.7% (P&lt;0.05) decline of the rise time constant of peaks but unchanged peak duration at the half maximal amplitude. Conclusion. We conclude that pharmacological activation of transient receptor potential vanilloid-type 4 ion channels by their selective agonist GSK1016790A decreased the contractile activity of both colon smooth muscle cells in Parkinson’s disease rats’ model and the myometrium in pregnant rats

The role of mast cells, C-fibers, and cholinergic transmission in the reduction of tracheal muscle and mronchi of sensitized animal

The article considers the role of stabilization of mast cell membranes, blockade of neuromuscular transmission and inactivation of C-fibers in the contractile activity of smooth muscles of the trachea and bronchi of sensitized rats. The studies were conducted on isolated preparations using electrical stimulation of postganglionic nerves (frequency - 30 stim/s, duration - 0.5 ms, amplitude - 20 V, duration of stimulation - 10 s). The study used cromolyn sodium, atropine, and capsaicin. As a result of the experiments, it was found that the leading role in the contraction of the muscles of the trachea and bronchi of a sensitized rat belongs to mast cells. However, the maximum effect of normalization of smooth muscle contraction can be achieved only in the case of a complex effect - blockade of neuromuscular transmission, stabilization of mast cell membranes, and inactivation of C-fibers.

MP54-12 IMPAIRMENT OF AMPK-α2 BY ISCHEMIA PROVOKES DETRUSOR OVERACTIVITY VIA CELLULAR STRESS SENSORS

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Basic Research & Pathophysiology (MP54)1 Apr 2020MP54-12 IMPAIRMENT OF AMPK-α2 BY ISCHEMIA PROVOKES DETRUSOR OVERACTIVITY VIA CELLULAR STRESS SENSORS Jinghua Yang, Yedan Li, Michelle Azad, and Kazem Azadzoi* Jinghua YangJinghua Yang More articles by this author , Yedan LiYedan Li More articles by this author , Michelle AzadMichelle Azad More articles by this author , and Kazem Azadzoi*Kazem Azadzoi* More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000916.012AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Adenosine monophosphate-activated protein kinase alpha 2 (AMPK-α2) is a subunit of AMPK with catalytic kinase domain that senses cellular energy deprivation and signals cellular nutrients deficiency. Our goal was to examine functional consequences of AMPK-α2 responses in bladder ischemia. METHODS: A rat model of bladder ischemia was developed by engendering aorto-iliac arterial atherosclerosis. After 8 weeks, ischemic and sham control bladder tissues were processed for analysis of AMPK-α2 expression and AMPK-α2 translocation and activity using western blotting and ELISA. Ischemia-mediated cellular stress was examined by real-time PCR analysis of the cellular stress sensor upstream stimulatory factor 1 (USF1). USF1-mediated smooth muscle contractile activity was examined in the organ bath. In follow up experiments, rats with bladder ischemia were treated with the AMPK-α2 activator 5-aminoimidazole-4-carboxamide-1-beta-D ribofuranoside (AICAR) or placebo in daily basis for 4 weeks then conscious cystometry was performed and bladder tissues were processed for analysis of AMPK-α2, USF1, and smooth muscle contractile activity, as described earlier. RESULTS: Ischemia upregulated AMPK-α2 expression while blocking AMPK-α2 translocation from cytoplasm to the nucleus. Blockade of AMPK-α2 translocation was associated with significant decrease in AMPK-α2 catalytic activity, suggesting loss of cellular energy deprivation sensing via AMPK-α2 in bladder ischemia. Impairment of AMPK-α2 activity upregulated the expression of cellular stress sensor USF1, implying cellular stress responses via AMPK-α2/USF1 pathway in bladder ischemia. These changes shifted contractile reactivity of ischemic bladder tissues to electrical field stimulation (EFS) to the left and produced cystometric changes consistent with detrusor overactivity. Treatment of bladder tissues with the USF1 inhibitor C527 reversed hyperreactivity to EFS. Treatment of rats with the AMPK-α2 activator AICAR significantly downregulated USF1 expression and diminished cystometric markers of detrusor overactivity in bladder ischemia. CONCLUSIONS: Impairment of AMPK-α2 by ischemia upregulated USF1 and provoked detrusor overactivity by activation of cellular stress responses. The mechanism appeared to involve USF1-directed smooth muscle hyperreactivity via cellular stress signaling pathway. Our data suggest that activators of AMPK-α2 and inhibitors of USF1 may have valuable therapeutic potentials against overactive bladder. Source of Funding: Supported by Merit Review Award Number I01 BX004372 from the United States (U.S.) Department of Veterans Affairs Biomedical Laboratory R&D (BLRD) Service. © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e795-e796 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jinghua Yang More articles by this author Yedan Li More articles by this author Michelle Azad More articles by this author Kazem Azadzoi* More articles by this author Expand All Advertisement PDF downloadLoading ...

Inhibition of Na(+),K(+)-ATPase and activation of myosin ATPase by calix[4]arene C-107 cause stimulation of isolated smooth muscle contractile activity

Inhibition of Na(+),K(+)-ATPase and activation of myosin ATPase by calix[4]arene C-107 cause stimulation of isolated smooth muscle contractile activity

Systemic distribution of progesterone receptor subtypes in human tissues

Progesterone receptor (PR) is expressed in a wide variety of human tissues, including both reproductive and non-reproductive tissues. Upon binding to the PR, progesterone can display several non-reproductive functions, including neurosteroid activity in the central nervous system, inhibition of smooth muscle contractile activity in the gastrointestinal tract, and regulating the development and maturation of the lung. PR exists as two major isoforms, PRA and PRB. Differential expression of these PR isoforms reportedly contributes to different biological activities of the hormone. However, the distribution of the PR isoforms in human tissues has remained virtually unexplored.In this study, we immunolocalized PR expression in various human tissues using PR (1294) specific antibody, which is capable of detecting both PRA and PRB, and PRB (250H11) specific antibody. Tissues from the uterus, ovary, breast, placenta, prostate, testis, cerebrum, cerebellum, pituitary, spinal cord, esophagus, stomach, small intestine, colon, pancreas, liver, kidney, urinary bladder, lung, heart, aorta, thymus, adrenal gland, thyroid, spleen, skin, and bone were examined in four different age groups (fetal, pediatric, young, and old) in male and female subjects. PR and PRB were detected in the nuclei of cells in the female reproductive system, in both the nuclei and cytoplasm of pituitary gland and pancreatic acinar cells, and only in the cytoplasm of cells in the testis, stomach, small intestine, colon, liver, kidney, urinary bladder, lung, adrenal gland, and skin. Of particular interest, total PRB expression overlapped with that of total PR expression in most tissues but was negative in the female fetal reproductive system. The findings indicate that progesterone could affect diverse human organs differently than from reproductive organs. These findings provide new insights into the novel biological roles of progesterone in non-reproductive organs.

Characterization of cystic fibrosis airway smooth muscle cell proliferative and contractile activities.

Cystic fibrosis (CF) is a genetic disease that causes multiple airway abnormalities. Two major respiratory consequences of CF are airway hyperresponsiveness (AHR) and airway remodeling. Airway smooth muscle (ASM) is hypothesized to be responsible for the airway dysfunction, since their thickening is involved in remodeling, and excessive contraction by the ASM may cause AHR. It is unclear whether the ASM is intrinsically altered to favor increased contractility or proliferation or if microenvironmental influences induce pathological behavior in vivo. In this study, we examined the contractile and proliferative properties of ASM cells isolated from healthy donor and CF transplant lungs. Assays of proliferation showed that CF ASM proliferates at a higher rate than healthy cells. Through calcium analysis, no differences in contractile activation in response to histamine were found. However, CF ASM cells lagged in their reuptake of calcium in the sarcoplasmic reticulum. The combination CFTR corrector and potentiator, VX-809/770, used to restore CFTR function in CF ASM, resulted in a reduction in proliferation and in a normalization of calcium reuptake kinetics. These results show that impaired CFTR function in ASM cells causes intrinsic changes in their proliferative and contractile properties.

Mechanosensitive Ion Channels in the Development of Ileus

IntroductionApproximately 30% of trauma patients develop ileus, a decrease or cessation of intestinal motility resulting in pathological distension of the intestinal wall. Mechanosensitive ion channels play a role in both the physiological and pathological response to mechanical stimuli.ObjectiveThe objective of this study was to determine if mechanosensitive ion channels play a role in the development of ileus and the response of the intestine to pathological stretch.MethodsIn a rodent model, we induced ileus by a combination of hemodilution and mesenteric venous hypertension. We measured intestinal function using an ex vivo organ bath system. We also measured smooth muscle myosin light chain phosphorylation and intestinal wall fluid content. We collected tissue for microarray analysis.ResultsIntestinal wall fluid content increased significantly, indicating the development of intestinal edema. Edema development resulted in distension of the intestinal wall, decreased intestinal smooth muscle contractile activity, and decreased smooth muscle myosin light chain phosphorylation. We used microarray analysis to compare normal (unstretched) intestinal smooth muscle to edematous (stretched) intestinal smooth muscle to characterize changes in ion channel expression. We identified hyperpolarization‐activated cyclic nucleotide‐gated 2 (HCN2), a cyclic nucleotide gated ion channel, which is also stretch‐activated. HCN2 gene expression decreased in edematous intestinal tissue. In the ex vivo organ bath system, we tested the effects of HCN2 inhibitors on intestinal function. In preliminary experiments, HCN2 inhibition with ZD7288 resulted in decreased response to carbachol, with little change in spontaneous contractile activity or frequency.ConclusionsOur data suggest that HCN2 downregulation/inhibition can suppress intestinal contractile activity. Thus, HCN2 is a potential therapeutic target for improving intestinal motility. In future experiments, we will determine the role of HCN2 in the intestinal response to stretch.Support or Funding InformationHungarian National Research Development and Innovation Office (K120669, EFOP‐3.6.2‐16‐2017‐00006)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of vesical and perfusion pressure on perfusate flow, and flow on vesical pressure, in the isolated perfused working pig bladder reveal a potential mechanism for the regulation of detrusor compliance.

Although there is evidence that deficits in bladder blood flow negatively impact bladder function, the effects of vesical, and perfusion pressures on bladder perfusion (perfusate flow), and of perfusate flow on vesical pressure, remain poorly understood. The present study used the isolated perfused working pig bladder model to examine the relationships between blood flow, and vesical and perfusion pressures. Vesical arteries of pig bladders obtained from a local slaughterhouse were cannulated and perfused with Krebs-Henseleit solution at different pressures, and with carbachol to cause bladder contraction. The urethra of each bladder was cannulated to permit filling (10 mL/min), isovolumetric contraction and emptying. A ureter was cannulated with a pressure sensor to monitor vesical pressure. When at rest (50 mL vesical volume), bladder vesical pressure was 8.06 ± 1.5 mmHg and perfusate flow driven by a pressure gradient of 105 mmHg was 22.5 ± 2 mL/min (58.9 ± 7.8 mL/min-100 g). During filling, vesical pressure increased and flow decreased, but not necessarily in-parallel. Perfusate flow decreased transiently during isovolumetric contraction, and flow increased during emptying. A reduction in perfusion pressure from ∼105 to ∼40 mmHg reduced flow from ∼70 to ∼20 mL/min-100g, and reduced flow correlated with reduced vesical pressure. Perfusate flow is dependent on bladder perfusion pressure, and not necessarily reciprocally dependent on vesical pressure. Vesical pressure is highly sensitive to the level of perfusate flow, which supports the hypothesis that vesical pressure is dependent on the level of detrusor smooth muscle contractile activity (tone), and that compliance is dependent on bladder perfusion.