Neural regulation of intestinal smooth muscle growth in vitro

2000 ◽  
Vol 279 (3) ◽  
pp. G511-G519 ◽  
Author(s):  
M. G. Blennerhassett ◽  
S. Lourenssen
Keyword(s):  
Smooth Muscle ◽  
Sympathetic Neurons ◽  
Muscle Growth ◽  
Scorpion Venom ◽  
Enteric Neurons ◽  
Intestinal Smooth Muscle ◽  
Early Event ◽  
Thymidine Uptake

The loss of intrinsic neurons is an early event in inflammation of the rat intestine that precedes the growth of intestinal smooth muscle cells (ISMC). To study this relationship, we cocultured ISMC and myenteric plexus neurons from the rat small intestine and examined the effect of scorpion venom, a selective neurotoxin, on ISMC growth. By 5 days after neuronal ablation, ISMC number increased to 141 ± 13% ( n = 6) and the uptake of [3H]thymidine in response to mitogenic stimulation was nearly doubled. Atropine caused a dose-dependent increase in [3H]thymidine uptake in cocultures, suggesting the involvement of neural stimulation of cholinergic receptors in regulation of ISMC growth. In contrast, coculture of ISMC with sympathetic neurons increased [3H]thymidine uptake by 45–80%, which was sensitive to propranolol (30 μM) and was lost when the neurons were separated from ISMC by a permeable filter. Western blotting showed that coculture with myenteric neurons increased α-smooth muscle-specific actin nearly threefold to a level close to ISMC in vivo. Therefore, factors derived from enteric neurons maintain the phenotype of ISMC through suppression of the growth response, whereas catecholamines released by neurons extrinsic to the intestine may stimulate their growth. Thus inflammation-induced damage to intestinal innervation may initiate or modulate ISMC hyperplasia.

Neuronal nitric oxide inhibits intestinal smooth muscle growth

2010 ◽  
Vol 298 (6) ◽  
pp. G896-G907 ◽  
Author(s):  
Anne-Marie Pelletier ◽  
Shriram Venkataramana ◽  
Kurtis G. Miller ◽  
Brian M. Bennett ◽  
Dileep G. Nair ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Enteric Neurons ◽  
Rat Colon ◽  
Intestinal Smooth Muscle ◽  
Trinitrobenzene Sulfonic Acid ◽  
Thymidine Uptake ◽  
Circular Smooth Muscle

Hyperplasia of smooth muscle contributes to the thickening of the intestinal wall that is characteristic of inflammation, but the mechanisms of growth control are unknown. Nitric oxide (NO) from enteric neurons expressing neuronal NO synthase (nNOS) might normally inhibit intestinal smooth muscle cell (ISMC) growth, and this was tested in vitro. In ISMC from the circular smooth muscle of the adult rat colon, chemical NO donors inhibited [3H]thymidine uptake in response to FCS, reducing this to baseline without toxicity. This effect was inhibited by the guanylyl cyclase inhibitor ODQ and potentiated by the phosphodiesterase-5 inhibitor zaprinast. Inhibition was mimicked by 8-bromo (8-Br)-cGMP, and ELISA measurements showed increased levels of cGMP but not cAMP in response to sodium nitroprusside. However, 8-Br-cAMP and cilostamide also showed inhibitory actions, suggesting an additional role for cAMP. Via a coculture model of ISMC and myenteric neurons, immunocytochemistry and image analysis showed that innervation reduced bromodeoxyuridine uptake by ISMC. Specific blockers of nNOS (7-NI, NAAN) significantly increased [3H]thymidine uptake in response to a standard stimulus, showing that nNOS activity normally inhibits ISMC growth. In vivo, nNOS axon number was reduced threefold by day 1 of trinitrobenzene sulfonic acid-induced rat colitis, preceding the hyperplasia of ISMC described earlier in this model. We conclude that NO can inhibit ISMC growth primarily via a cGMP-dependent mechanism. Functional evidence that NO derived from nNOS causes inhibition of ISMC growth in vitro predicts that the loss of nNOS expression in colitis contributes to ISMC hyperplasia in vivo.

Proliferation modulates intestinal smooth muscle phenotype in vitro and in colitis in vivo

2011 ◽  
Vol 300 (5) ◽  
pp. G903-G913 ◽  
Author(s):  
Dileep G. Nair ◽  
T. Y. Han ◽  
S. Lourenssen ◽  
Michael G. Blennerhassett
Keyword(s):  
Smooth Muscle ◽  
Sulfonic Acid ◽  
Molecular Mechanisms ◽  
Muscle Protein ◽  
Rat Colon ◽  
Intestinal Smooth Muscle ◽  
Trinitrobenzene Sulfonic Acid ◽  
Thymidine Uptake

Intestinal inflammation causes an increased intestinal wall thickness, in part, due to the proliferation of smooth muscle cells, which impairs the contractile phenotype elsewhere. To study this, cells from the circular muscle layer of the rat colon (CSMC) were isolated and studied, both in primary culture and after extended passage, using quantitative PCR, Western blot analysis, and immunocytochemistry. By 4 days in vitro, both mRNA and protein for the smooth muscle marker proteins α-smooth muscle actin, desmin, and SM22-α were reduced by >50%, and mRNA for cyclin D1 was increased threefold, evidence for modulation to a proliferative phenotype. Continued growth caused significant further decrease in expression, evidence that phenotypic loss in CSMC was proportional to the extent of proliferation. In CSMC isolated at day 2 of trinitrobenzene sulfonic acid-induced colitis, flow cytometry and Western blotting showed that these differentiated markers were reduced in mitotic CSMC, while similar to control in nonmitotic CSMC. By day 35 post-trinitrobenzene sulfonic acid, when inflammation has resolved, CSMC were hypertrophic, but, nonetheless, showed markedly decreased expression of smooth muscle protein markers per cell. In vitro, day 35 CSMC displayed an accelerated loss of phenotype and increased thymidine uptake in response to serum or PDGF-BB. Furthermore, carbachol-induced expression of phospho-AKT (a marker of cholinergic response) was lost from day 35 CSMC in vitro, while retained in control cells. Therefore, proliferation reduces the expression of smooth-muscle-specific markers in CSMC, possibly leading to altered contractility. However, inflammation-induced proliferation in vivo also causes lasting changes that include unexpected priming for an exaggerated response to proliferative stimuli. Identification of the molecular mechanisms of intestinal smooth muscle cell phenotypic modulation will be helpful in reducing the detrimental effects of inflammation.

Effects of Buthus martensii Karsch scorpion venom on the release of noradrenaline from in vitro and in vivo rat preparations

1994 ◽  
Vol 72 (8) ◽  
pp. 855-861 ◽  
Author(s):  
Sylvain Foucart ◽  
Rui Wang ◽  
Pierre Moreau ◽  
Rémi Sauvé ◽  
Jacques de Champlain ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Noradrenaline Release ◽  
Sympathetic Neurons ◽  
Scorpion Venom ◽  
Dependent Manner ◽  
Release Of Noradrenaline ◽  
Adult Rat ◽  
Isolated Atria

The aim of this study was to test the neuronal effects of the Chinese Buthus martensii Karsch (BMK) scorpion venom in vivo and in vitro in order to understand the mechanism involved in the cardiovascular pressor effect of this venom. In conscious unrestrained rats, administration of 100 μg/kg i.v. BMK venom induced an increase in blood pressure, which was associated with a significant increase in plasma noradrenaline. In isolated atria, BMK also induced an increase in the stimulation-induced release of [3H]noradrenaline in a dose-dependent manner. The modulatory effect of agents acting at sympathetic prejunctional adrenoceptors on [3H]noradrenaline release was not altered by BMK venom administration. Finally, it was observed that 100 μg/mL BMK venom increased the intracellular calcium concentration in acutely dissociated sympathetic neurons from adult rat superior cervical ganglion. This action appeared to be mainly due to an influx of extracellular calcium. BMK venom induced a small rise in intracellular calcium in the absence of external calcium, indicating that it may also mobilize calcium from intracellular stores. The results observed in this study suggest that BMK venom may induce pressor responses by releasing noradrenaline from the sympathetic nerve terminals and that activation of neuronal calcium channels may be involved in that process.Key words: scorpion venom, noradrenaline release, presynaptic modulation, intracellular calcium.

scholarly journals Collagen and heparan sulfate coatings differentially alter cell proliferation and attachment in vitro and in vivo

TECHNOLOGY ◽  
2016 ◽  
Vol 04 (03) ◽  
pp. 159-169
Author(s):  
Christopher M. Walthers ◽  
Chase J. Lyall ◽  
Alireza K. Nazemi ◽  
Puneet V. Rana ◽  
James C.Y. Dunn
Keyword(s):  
Tissue Engineering ◽  
Cell Proliferation ◽  
Smooth Muscle ◽  
Heparan Sulfate ◽  
Intestinal Smooth Muscle ◽  
Smooth Muscle Tissue ◽  
Cell Numbers ◽  
Survival And Growth

Tissue engineering is an innovative field of research applied to treat intestinal diseases. Engineered smooth muscle requires dense smooth muscle tissue and robust vascularization to support contraction. The purpose of this study was to use heparan sulfate (HS) and collagen coatings to increase the attachment of smooth muscle cells (SMCs) to scaffolds and improve their survival after implantation. SMCs grown on biologically coated scaffolds were evaluated for maturity and cell numbers after 2, 4 and 6 weeks in vitro and both 2 and 6 weeks in vivo. Implants were also assessed for vascularization. Collagen-coated scaffolds increased attachment, growth and maturity of SMCs in culture. HS-coated implants increased angiogenesis after 2 weeks, contributing to an increase in SMC survival and growth compared to HS-coated scaffolds grown in vitro. The angiogenic effects of HS may be useful for engineering intestinal smooth muscle.

Effect of purified Clostridium difficile toxins on intestinal smooth muscle. II. Toxin B

1989 ◽  
Vol 256 (4) ◽  
pp. G767-G772
Author(s):  
R. J. Gilbert ◽  
C. Pothoulakis ◽  
J. T. LaMont
Keyword(s):  
Smooth Muscle ◽  
Clostridium Difficile ◽  
Membrane Depolarization ◽  
Intestinal Smooth Muscle ◽  
Toxin A ◽  
Toxin B ◽  
Direct Exposure ◽  
In Vitro Exposure

In the companion paper [Am. J. Physiol. 256 (Gastrointest. Liver Physiol. 19): G759-G766, 1989] we showed that highly purified Clostridium difficile toxin A had a profound effect on intestinal smooth muscle after in vivo but not in vitro exposure. In this study we assessed the effects of in vivo and in vitro exposure to C. difficile toxin B on simultaneous measurements of intracellular membrane potential and contractility in rabbit ileal smooth muscle. Direct exposure of ileal smooth muscle to toxin B (0.1-60 micrograms/ml) in vitro caused membrane depolarization and inhibition of action potential frequency, amplitude, and peak voltage, but no effect on slow wave frequency or amplitude was seen. Toxin exposure also resulted in inhibition of the amplitude of carbachol-induced contractions, with phasic contractions being significantly more sensitive to the effect of toxin B than tonic contractions over the complete dose range. The electromechanical effects of toxin B were not affected by prior administration of tetrodotoxin, atropine, hexamethonium, or phentolamine. In contrast, toxin B administered in vivo into an isolated ileal loop had no effect on spontaneous electromechanical properties of excised smooth muscle strips. Our results indicate that direct exposure in vitro of ileal smooth muscle to C. difficile toxin B causes membrane depolarization in association with inhibition of electromechanical activity. This effect, in combination with the indirect effects of toxin A, may contribute to altered intestinal motility during diarrhea caused by C. difficile.

Mitogenic factors promoting intestinal smooth muscle cell proliferation

2010 ◽  
Vol 299 (4) ◽  
pp. C805-C817 ◽  
Author(s):  
Roger D. P. Stanzel ◽  
Sandra Lourenssen ◽  
Dileep G. Nair ◽  
Michael G. Blennerhassett
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Rat Colon ◽  
Intestinal Smooth Muscle ◽  
Trinitrobenzene Sulfonic Acid

Intestinal smooth muscle cells are normally quiescent, but in the widely studied model of trinitrobenzene sulfonic acid (TNBS)-induced colitis in the rat, the onset of inflammation causes proliferation that leads to increased cell number and an altered phenotype. The factors that drive this are unclear and were studied in primary cultures of circular smooth muscle cells (CSMC) from the rat colon. While platelet-derived growth factor (PDGF)-AA, fibroblast growth factor (FGF), and epidermal growth factor (EGF) were ineffective, PDGF-BB and insulin-like growth factor-1 (IGF-1) caused significant increase in [3H]thymidine incorporation, bromodeoxyuridine uptake, and increased CSMC number, with PDGF-BB (≥0.2 nM) substantially more effective than IGF-1. Surprisingly, CSMC lacked expression of PDGF receptor-β (PDGF-Rβ) upon isolation but by 4 days in vitro, CSMC gained expression of PDGF-Rβ as shown by quantitative PCR, Western blot analysis, and immunocytochemistry; these CSMC responded to PDGF-BB but not IGF-1. PDGF-BB caused PDGF-Rβ phosphorylation and mobilization from the surface membrane, leading to activation of both Akt and ERK signaling pathways, which were essential for subsequent proliferation. In contrast, PDGF-AA, FGF, EGF, and IGF-1 were ineffective. In vivo, control CSMC lacked expression of PDGF-Rβ. However, this changed rapidly with TNBS-colitis, and by day 2 when CSMC proliferation in vivo is maximal, freshly isolated CSMC showed on-going PDGF-Rβ phosphorylation that was further increased by exogenous PDGF-BB. This suggests that the onset of PDGF-Rβ expression is a key factor in CSMC growth in vitro and in vivo, where inflammation may damage intrinsic inhibitory mechanisms and thus lead to hyperplasia.

Targeting Matrix Metalloproteinases in Atherosclerosis and Cardiovascular Dysfunction

2019 ◽  
Vol 70 (2) ◽  
pp. 718-720
Author(s):  
Lucia Corina Dima-Cozma ◽  
Sebastian Cozma ◽  
Delia Hinganu ◽  
Cristina Mihaela Ghiciuc ◽  
Florin Mitu
Keyword(s):  
Smooth Muscle ◽  
Matrix Metalloproteinases ◽  
Cholesterol Synthesis ◽  
Balloon Dilation ◽  
Aortic Aneurysms ◽  
Arterial Lesions ◽  
Smooth Muscle Cell Migration ◽  
And Migration

Matrix metalloproteinases (MMPs) are the primary mediators of extracellular remodeling and their properties are useful in diagnostic evaluation and treatment. They are zinc-dependent proteases. MMPs have been involved in the mechanisms of atherosclerosis in various arterial areas, ischemic heart disease and myocardial infarction, atrial fibrillation and aortic aneurysms. Recently, MMP9 has been implicated in dyslipidemia and cholesterol synthesis by the liver. Increased MMP expression and activity has been associated with neointimal arterial lesions and migration of smooth muscle cells after arterial balloon dilation, while MMP inhibition decreases smooth muscle cell migration in vivo and in vitro.

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