Different muscarinic receptor subtypes modulate proliferation of primary human detrusor smooth muscle cells via Akt/PI3K and map kinases

CD38 plays an age-related role in cholinergic deregulation of airway smooth muscle contractility

BACKGROUND

Allergen-induced airway hyperresponsiveness in neonatal mice, but not adult mice, is caused by elevated innervation and consequent cholinergic hyperstimulation of airway smooth muscle (ASM). Whether this inflammation-independent mechanism contributes to ASM hypercontraction in childhood asthma warrants investigation.

OBJECTIVE

We aimed to establish the functional connection between cholinergic stimulation and ASM contractility in different human age groups.

METHODS

First, we used a neonatal mouse model of asthma to identify age-related mediators of cholinergic deregulation of ASM contractility. Next, we conducted validation and mechanistic studies in primary human ASM cells and precision-cut lung slices from young (<5 years old) and adult (>20 years old) donor lungs. Finally, we evaluated the therapeutic potential of the identified cholinergic signaling mediators using culture models of human ASM hypercontraction.

RESULTS

ASM hypercontraction due to cholinergic deregulation in early postnatal life requires CD38. Mechanistically, cholinergic signaling activates the phosphatidylinositol 3-kinase/protein kinase B pathway in immature ASM cells to upregulate CD38 levels, thereby augmenting the Ca2+ response to contractile agonists. Strikingly, this early-life, CD38-mediated ASM hypercontraction is not alleviated by the β-agonist formoterol.

CONCLUSIONS

The acetylcholine-phosphatidylinositol 3-kinase/protein kinase B-CD38 axis is a critical mechanism of airway hyperresponsiveness in early postnatal life. Targeting this axis may provide a tailored treatment for children at high risk for allergic asthma.

Use of bladder antimuscarinics is associated with an increased risk of dementia: a retrospective population-based case-control study

The association between bladder antimuscarinic use and dementia development is unclear. We used data from the Taiwan National Health Insurance Research Database to determine the association between the exposure dose and duration of bladder antimuscarinics and the subsequent dementia risk. We enrolled participants aged 55 years or more and defined a dementia cohort (International Classification of Diseases, Ninth Revision, Clinical Modification codes 290, 294.1, and 331.0). We used a propensity score matching method, and randomly enrolled two controls without dementia. We evaluated dementia risk with respect to the exposure dose and duration of treatment with seven bladder antimuscarinics (oxybutynin, propiverine, tolterodine, solifenacin, trospium, darifenacin, and fesoterodine) used for at least 1 year before the index date, after adjusting for age, sex, comorbidities, and medications. The dementia risk was 2.46-fold (95% confidence interval: 2.22–2.73) higher in Taiwanese patients who used bladder antimuscarinics for ≥ 1 year than in those who were not exposed to this treatment. The risk proportionally increased with increasing doses of antimuscarinics for less than 4 years. Taiwanese patients aged 55 years or more on bladder antimuscarinics exhibited a higher risk of dementia. Additional studies in other countries are required to determine whether this result is valid worldwide.

Nicotine promotes the development of non-small cell lung cancer through activating LINC00460 and PI3K/Akt signaling

Objective: Nicotine, the main ingredient in tobacco, is identified to facilitate tumorigenesis and accelerate metastasis in tumor. Studies in recent years have reported that long intergenic non-protein coding RNA 460 (LINC00460) is strongly associated with lung cancer poor prognosis and nicotine dependence. Nonetheless, it is unclear whether nicotine promotes the development of lung cancer through activation of LINC00460. Methods: We determined that LINC00460 expression in lung cancer tissues and the prognosis in patients with non-small cell lung carcinoma (NSCLC) using Gene Expression Profiling Interactive Analysis (GEPIA) website and The Cancer Genome Atlas (TCGA) database. Through in vitro experiments, we studied the effects of nicotine on LINC00460 in NSCLC cells lines using Cell Counting Kit-8 (CCK-8), transwell test, flow cytometry, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot assays. Results: We identified the significant up-regulated expression level of LINC00460 in NSCLC tissues and cell lines, especially, the negative correlation of LINC00460 expression level with overall survival (OS). In in vitro experiments, LINC00460 was overexpressed in NSCLC cell lines under nicotine stimulation. Nicotine could relieve the effect of LINC00460 knockdown on NSCLC cell proliferation, migration and apoptosis. The same influence was observed on PI3K/Akt signaling pathway. Conclusions: In summary, this is the first time to examine the potential roles of LINC00460 in lung cancer cell proliferation, migration and apoptosis induced by nicotine. This may help to develop novel therapeutic strategies for the prevention and treatment of metastatic tumors from cigarette smoke-caused lung cancer by blocking the nicotine-activated LINC00460 pathway.

Differentiation of human glioblastoma U87 cells into cholinergic neuron

To facilitate research methodologies for investigating the role of cholinergic nerves in many diseases, establishing an in vitro cholinergic neuron model is necessary. In this study, we investigated whether human glioblastoma U87 cells could be differentiated into cholinergic neurons in vitro. Sodium butyrate was used as the differentiation agent. The differentiated cells established by inducing U87 cells with sodium butyrate were named D-U87 cells. Immunofluorescence was used to label the neuronal markers MAP2, NF-M, and ChAT and the glial marker GFAP in D-U87 cells. Flow cytometry was used to measure cell cycle distribution in D-U87 cells. PCR, protein chip, and western blot assays were used to measure the expression levels of muscarinic cholinergic receptor 1 (M1), M4, ChAT, SYP and Akt. ELISA was used to measure neurotransmitter levels. As a result, we found that sodium butyrate induced U87 cell differentiation into cells with neuronal characteristics and increased not only the expression levels of the cholinergic neuron-related proteins M1, M4, ChAT and SYP in D-U87 cells but also the acetylcholine neurotransmitters in D-U87 cells. Moreover, the Akt protein expression in D-U87 cells was increased compared with that in U87 cells. Finally, we found that M1, M4, ChAT and SYP protein expression and acetylcholine secretion levels were significantly decreased in D-U87 cells after treatment with the Akt inhibitor MK-2206. These results demonstrate that D-U87 cells exhibit cholinergic neuron characteristics and that sodium butyrate induced U87 cell differentiation into cholinergic neuron partially through Akt signaling.

2-Methoxyestradiol attenuates chronic-intermittent-hypoxia-induced pulmonary hypertension through regulating microRNA-223

Pulmonary hypertension (PH) is prevalent in patients with obstructive sleep apnea (OSA) syndrome, and coexistence of PH and OSA indicates a worse prognosis and higher mortality. Chronic intermittent hypoxia (CIH) is the key pathogenesis of OSA. Also, microRNA-223 (miR-223) plays a role in the regulation of CIH-induced PH process. However, the detailed mechanism of CIH inducing PH is still unclear. This study aimed to investigate the pathological process of CIH associated PH and explore the potential therapeutic methods. In this study, adult Sprague-Dawley rats were exposed to CIH or normoxic (N) conditions with 2-methoxyestradiol (2-Me) or vehicle treatment for 6 weeks. The results showed that 2-Me treatment reduced the progression of pulmonary angiogenesis in CIH rats, and alleviated proliferation, cellular migration, and reactive oxygen species formation was induced by CIH in pulmonary artery smooth muscle cells (PASMCs). CIH decreased the expression of miR-223, whereas 2-Me reversed the downregulation of miR-223 both in vivo and in vitro. Furthermore, the antiangiogenic effect of 2-Me observed in PASMCs was abrogated by miR-223 inhibitor, while enhanced by miR-223 mimic. These findings suggested that miR-223 played an important role in the process of CIH inducing PH, and 2-Me might reverse CIH-induced PH via upregulating miR-223.

Muscarinic cholinergic signaling and overactive bladder-like symptoms associated with invasive bladder cancer

The objective of the present study was to explore the association between muscarinic cholinergic signaling and urothelial bladder tumors. Possible associations among overactive bladder (OAB) symptoms and bladder tumors were retrospectively investigated using a multicenter Chinese database with prospectively collected data since 2010. Firstly, it was demonstrated that OAB symptoms, such as urgency, were more severe in patients with invasive bladder cancer and were associated with a reduced prognosis. Following this, muscarinic cholinergic receptor 3 (M3R) expression in urothelium was determined to be lower in invasive cancer tissue than in adjacent non-cancerous tissue, yet M3R upregulation was associated with a reduced progression free survival (PFS) time. Additionally, it was also demonstrated that muscarinic cholinergic receptor 2 (M2R) was upregulated in the sub-urothelium, and this was also associated with a reduced PFS time. Furthermore, it was determined that cholinesterase and acetylcholinesterase were lower in invasive cancer than in non-invasive cancer. In conclusion, the results indicated that M3R expression was downregulated in invasive bladder cancer, which may have a role as a protective anti-oncogene, in contrast to its oncogenic role in numerous other cancer types. Therefore, muscarinic cholinergic signaling may be a novel therapeutic target for treating bladder cancer.

Aclidinium bromide inhibits the growth and metastasis of gastric cancer MKN‑28 cells via the PI3K signaling pathway

The present study investigated the effect and underling mechanisms of aclidinium bromide, a novel, inhaled long‑acting muscarinic antagonist, on the development of gastric cancer. Human gastric cancer MKN‑28 cells, as a model in vitro, were treated with aclidinium bromide and dimethyl sulfoxide. Cell Counting Kit‑8 assay, transwell assay and flow cytometry were used to assess cell proliferation, invasion/migration and apoptosis, respectively. In addition, western blotting was performed to determine the relative expression of proteins associated with apoptosis and the phosphatidylinositol‑3‑kinase (PI3K) signaling pathway. Optical density values of MKN‑28 cells were decreased in a time‑ and dose‑dependent manner in the aclidinium bromide treated group. Matrigel invasion analysis demonstrated the number of invasive cells were significantly decreased in the aclidinium bromide‑treated group when compared with the control group. Furthermore, aclidinium bromide led to the marked reduction of the number of MKN‑28 cells passing though the microwells of the transwell chamber. The expression levels of the anti‑apoptotic protein B‑cell lymphoma 2 (Bcl‑2) decreased, and the expression of pro‑apoptotic proteins active Caspase3 and Bcl‑2‑associated X protein increased concurrently following aclidinium bromide stimulation using western blotting. The phosphorylation of protein kinase B and mechanistic target of rapamycin were significantly inhibited in MKN‑28 cells treated with aclidinium bromide; and the activity of the downstream proteins such as p70S6K and Cyclin D1 were also significantly decreased. In conclusion, aclidinium bromide could inhibit gastric cancer cell proliferation and metastasis, which may be associated with the enhancement of apoptosis induced by the PI3K signaling pathway.

Increased expression of neuregulin 1 in the urothelium of rat bladder with partial bladder outlet obstruction

Background

This study determined whether changes in the expression of neuregulin (NRG) 1, erbB2 tyrosine kinase (ErbB2) and the M2 muscarinic receptor in the urothelium and detrusor muscle of the rat bladder were associated with partial bladder outlet obstruction (PBOO).

Methods

Male Sprague-Dawley rats (body weight 250–300 g) were used and subdivided into control (n = 10) and PBOO groups (n = 20). PBOO was induced for 21 days, and the expression of NRG1, ErbB2 and M2 muscarinic receptor mRNA and protein was evaluated using reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting, respectively.

Results

In the urothelium of rat bladder samples, protein expression and mRNA expression of NRG1, ErbB2 and M2 muscarinic receptor were significantly increased in the PBOO group compared to the control group (p < 0.05). Only mRNA expression levels of NRG1/ ErbB2 were higher in the detrusor muscle of the PBOO group compared to the control group (p < 0.05).

Conclusions

Our study demonstrated remarkable changes in the expression of NRG1/ErbB2 receptor mRNA and protein in the urothelium and muscle layer. These results suggest that NRG1 overexpression plays some kind of role against the PBOO-induced upregulated muscarinic receptors in detrusor overactivity.

Adipose stem cells enhance myoblast proliferation via acetylcholine and extracellular signal-regulated kinase 1/2 signaling

Introduction: In this study we investigated the interaction between adipose tissue–derived stem cells (ASCs) and myoblasts in co‐culture experiments. Methods: Specific inductive media were used to differentiate ASCs in vitro into a Schwann cell–like phenotype (differentiated adipose tissue–derived stem cells, or dASCs) and, subsequently, the expression of acetylcholine (ACh)‐related machinery was determined. In addition, the expression of muscarinic ACh receptors was examined in denervated rat gastrocnemius muscles. Results: In contrast to undifferentiated ASCs, dASCs expressed more choline acetyltransferase and vesicular acetylcholine transporter. When co‐cultured with myoblasts, dASCs enhanced the proliferation rate, as did ACh administration alone. Western blotting and pharmacological inhibitor studies showed that phosphorylated extracellular signal–regulated kinase 1/2 signaling mediated these effects. In addition, denervated muscle showed higher expression of muscarinic ACh receptors than control muscle. Discussion: Our findings suggest that dASCs promote proliferation of myoblasts through paracrine secretion of ACh, which could explain some of their regenerative capacity in vivo. Muscle Nerve57: 305–311, 2018

Acetylcholine-dependent upregulation of TASK-1 channels in thalamic interneurons by a smooth muscle-like signalling pathway

KEY POINTS

The ascending brainstem transmitter acetylcholine depolarizes thalamocortical relay neurons while it induces hyperpolarization in local circuit inhibitory interneurons. Sustained K⁺ currents are modulated in thalamic neurons to control their activity modes; for the interneurons the molecular nature of the underlying ion channels is as yet unknown. Activation of TASK-1 K⁺ channels results in hyperpolarization of interneurons and suppression of their action potential firing. The modulation cascade involves a non-receptor tyrosine kinase, c-Src. The present study identifies a novel pathway for the activation of TASK-1 channels in CNS neurons that resembles cholinergic signalling and TASK-1 current modulation during hypoxia in smooth muscle cells.

ABSTRACT

The dorsal part of the lateral geniculate nucleus (dLGN) is the main thalamic site for state-dependent transmission of visual information. Non-retinal inputs from the ascending arousal system and inhibition provided by γ-aminobutyric acid (GABA)ergic local circuit interneurons (INs) control neuronal activity within the dLGN. In particular, acetylcholine (ACh) depolarizes thalamocortical relay neurons by inhibiting two-pore domain potassium (K_2P ) channels. Conversely, ACh also hyperpolarizes INs via an as-yet-unknown mechanism. By using whole cell patch-clamp recordings in brain slices and appropriate pharmacological tools we here report that stimulation of type 2 muscarinic ACh receptors induces IN hyperpolarization by recruiting the G-protein βγ subunit (Gβγ), class-1A phosphatidylinositol-4,5-bisphosphate 3-kinase, and cellular and sarcoma (c-Src) tyrosine kinase, leading to activation of two-pore domain weakly inwardly rectifying K⁺ channel (TWIK)-related acid-sensitive K⁺ (TASK)-1 channels. The latter was confirmed by the use of TASK-1-deficient mice. Furthermore inhibition of phospholipase Cβ as well as an increase in the intracellular level of phosphatidylinositol-3,4,5-trisphosphate facilitated the muscarinic effect. Our results have uncovered a previously unknown role of c-Src tyrosine kinase in regulating IN function in the brain and identified a novel mechanism by which TASK-1 channels are activated in neurons.

Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease

We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.

G-protein coupled receptor 34 knockdown impairs the proliferation and migration of HGC-27 gastric cancer cells in vitro

Background:

Overexpression of G-protein coupled receptor 34 (GPR34) affects the progression and prognosis of human gastric adenocarcinoma, however, the role of GPR34 in gastric cancer development and progression has not been well-determined. The current study aimed to investigate the effect of GPR34 knockdown on the proliferation, migration, and apoptosis of HGC-27 gastric cancer cells and the underlying mechanisms.

Methods:

The expression of GPR34 in gastric cancer cell line HGC-27 was detected by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. HGC-27 cells were employed to construct the stable GPR34 knockdown cell model in this study. Real-time RT-PCR and Western blotting were applied to validate the effect of short hairpin RNA (ShRNA) on the expression of GPR34 in HGC-27 gastric cells. The proliferation, migration of these cells were examined by Cell Counting Kit-8 and transwell. We also measured expression profile of PI3K/PDK1/AKT and ERK using Western blotting.

Results:

The ShRNA directed against GPR34 effectively inhibited both endogenous mRNA and protein expression levels of GPR34, and significantly down-regulated the expression of PIK3CB (P < 0.01), PIK3CD (P < 0.01), PDK1 (P < 0.01), phosphorylation of PDK1 (P < 0.01), Akt (P < 0.01), and ERK (P < 0.01). Furthermore, GPR34 knockdown resulted in an obvious reduction in HGC-27 cancer cell proliferation and migration activity (P < 0.01).

Conclusions:

GPR34 knockdown impairs the proliferation and migration of HGC-27 gastric cancer cells in vitro and provides a potential implication for therapy of gastric cancer.

M2muscarinic receptors inhibit cell proliferation and migration in urothelial bladder cancer cells

The role of muscarinic receptors in several diseases including cancer has recently emerged. To evaluate the hypothesis that muscarinic acetylcholine receptors may play a role in bladder cancer as well as in other tumor types, we investigated their expression in bladder tumor specimens. All examined samples expressed the M1, M2 and M3 receptor subtypes. We also found that the level of M2 transcripts, but not those of M1 or M3, significantly increased with the tumor histologic grade. In view of these results, we proceeded to investigate whether the M2 agonist Arecaidine had any effect on in vitro cell growth and migration of T24 cells, a bladder tumor cell line expressing the muscarinic receptors, including the M2 subtype. We observed that Arecaidine significantly reduced T24 and 5637 cell proliferation and migration in a concentration dependent manner. The silencing of M2 receptor by siRNA in T24 and 5637 cell lines showed the inability of Arecaidine (100 μM) to inhibit cell proliferation after 48 hours, whereas the use of M1 and M3 antagonists in T24 appeared not to counteract the Arecaidine effect, suggesting that the inhibition of cell proliferation was directly dependent on M2 receptor activation. These data suggest that M2 muscarinic receptors may play a relevant role in bladder cancer and represent a new attractive therapeutic target.

Actions of cAMP on calcium sensitization in human detrusor smooth muscle contraction

OBJECTIVES

To clarify the effect of cAMP on the Ca(2+) -sensitized smooth muscle contraction in human detrusor, as well as the role of novel exchange protein directly activated by cAMP (Epac) in cAMP-mediated relaxation.

MATERIALS AND METHODS

All experimental protocols to record isometric tension force were performed using α-toxin-permeabilized human detrusor smooth muscle strips. The mechanisms of cAMP-mediated suppression of Ca(2+) sensitization activated by 10 μm carbachol (CCh) and 100 μm GTP were studied using a selective rho kinase (ROK) inhibitor, Y-27632, and a selective protein kinase C (PKC) inhibitor, GF-109203X. The relaxation mechanisms were further probed using a selective protein kinase A (PKA) activator, 6-Bnz-cAMP and a selective Epac activator, 8-pCPT-2'-O-Me-cAMP.

RESULTS

We observed that CCh-induced Ca(2+) sensitization was inhibited by cAMP in a concentration-dependent manner. GF-109203X (10 μm) but not Y-27632 (10 μm) significantly enhanced the relaxation effect induced by cAMP (100 μm). 6-Bnz-cAMP (100 μm) predominantly decreased the tension force in comparison with 8-pCPT-2'-O-Me-cAMP (100 μm).

CONCLUSIONS

We showed that cAMP predominantly inhibited the ROK pathway but not the PKC pathway. The PKA-dependent pathway is dominant, while Epac plays a minor role in human detrusor smooth muscle Ca(2+) sensitization.

Inflammatory cytokine COX-2 mediated cell proliferation through increasing cyclin D1 expression induced by inorganic arsenic in SV-HUC-1 human uroepithelial cells

Inorganic arsenic promotes SV-HUC-1 cells proliferation.

Gene expression of muscarinic, tachykinin, and purinergic receptors in porcine bladder: comparison with cultured cells

Urothelial cells, myofibroblasts, and smooth muscle cells are important cell types contributing to bladder function. Multiple receptors including muscarinic (M₃/M₅), tachykinin (NK₁/NK₂), and purinergic (P2X₁/P2Y₆) receptors are involved in bladder motor and sensory actions. Using female pig bladder, our aim was to differentiate between various cell types in bladder by genetic markers. We compared the molecular expression pattern between the fresh tissue layers and their cultured cell counterparts. We also examined responses to agonists for these receptors in cultured cells. Urothelial, suburothelial (myofibroblasts), and smooth muscle cells isolated from pig bladder were cultured (10–14 days) and identified by marker antibodies. Gene (mRNA) expression level was demonstrated by real-time PCR. The receptor expression pattern was very similar between suburothelium and detrusor, and higher than urothelium. The gene expression of all receptors decreased in culture compared with the fresh tissue, although the reduction in cultured urothelial cells appeared less significant compared to suburothelial and detrusor cells. Cultured myofibroblasts and detrusor cells did not contract in response to the agonists acetylcholine, neurokinin A, and β,γ-MeATP, up to concentrations of 0.1 and 1 mM. The significant reduction of M₃, NK₂, and P2X₁ receptors under culture conditions may be associated with the unresponsiveness of cultured suburothelial and detrusor cells to their respective agonists. These results suggest that under culture conditions, bladder cells lose the receptors that are involved in contraction, as this function is no longer required. The study provides further evidence that cultured cells do not necessarily mimic the actions exerted by intact tissues.