In Situ localization of specific interferon-γ producing immunocytes within the intestinal wall of chronically rejection rat allografts and the in vitro effect of interferon-γ on intestinal smooth muscle growth

1995 ◽  
Vol 108 (4) ◽  
pp. A938
Author(s):  
K.-J. Walgenbach ◽  
G.L. Su ◽  
P.F. Heeckt ◽  
T.L. Whiteside ◽  
A.J. Bauer
Keyword(s):  
Smooth Muscle ◽  
Muscle Growth ◽  
Interferon Γ ◽  
Intestinal Wall ◽  
Intestinal Smooth Muscle ◽  
Vitro Effect

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.

scholarly journals Prohormone convertases 1/3 and 2 together orchestrate the site-specific cleavages of progastrin to release gastrin-34 and gastrin-17

2008 ◽  
Vol 415 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Jens F. Rehfeld ◽  
Xiaorong Zhu ◽  
Christina Norrbom ◽  
Jens R. Bundgaard ◽  
Anders H. Johnsen ◽  
...  
Keyword(s):  
Structural Factors ◽  
Cleavage Sites ◽  
Wild Type ◽  
Prohormone Convertases ◽  
Site Specific ◽  
G Cells ◽  
Processing Site ◽  
Vitro Effect

Cellular synthesis of peptide hormones requires PCs (prohormone convertases) for the endoproteolysis of prohormones. Antral G-cells synthesize the most gastrin and express PC1/3, 2 and 5/6 in the rat and human. But the cleavage sites in progastrin for each PC have not been determined. Therefore, in the present study, we measured the concentrations of progastrin, processing intermediates and α-amidated gastrins in antral extracts from PC1/3-null mice and compared the results with those in mice lacking PC2 and wild-type controls. The expression of PCs was examined by immunocytochemistry and in situ hybridization of mouse G-cells. Finally, the in vitro effect of recombinant PC5/6 on progastrin and progastrin fragments containing the relevant dibasic cleavage sites was also examined. The results showed that mouse G-cells express PC1/3, 2 and 5/6. The concentration of progastrin in PC1/3-null mice was elevated 3-fold. Chromatography showed that cleavage of the Arg36Arg37 and Arg73Arg74 sites were grossly decreased. Accordingly, the concentrations of progastrin products were markedly reduced, α-amidated gastrins (-34 and -17) being 25% of normal. Lack of PC1/3 was without effect on the third dibasic site (Lys53Lys54), which is the only processing site for PC2. Recombinant PC5/6 did not cleave any of the dibasic processing sites in progastrin and fragments containing the relevant dibasic processing sites. The complementary cleavages of PC1/3 and 2, however, suffice to explain most of the normal endoproteolysis of progastrin. Moreover, the results show that PCs react differently to the same dibasic sequences, suggesting that additional structural factors modulate the substrate specificity.

Stretch-mediated visceral smooth muscle growth in vitro

1992 ◽  
Vol 262 (5) ◽  
pp. R895-R900
Author(s):  
O. M. Karim ◽  
K. Pienta ◽  
N. Seki ◽  
J. L. Mostwin
Keyword(s):  
Smooth Muscle ◽  
Dna Synthesis ◽  
De Novo ◽  
Specific Activity ◽  
Muscle Growth ◽  
Mechanical Stimulus ◽  
Trophic Factors ◽  
Taenia Coli ◽  
Visceral Smooth Muscle

An in vitro model of smooth muscle stretch was developed to study mechanical stimulus as a possible mediator of visceral smooth muscle growth and differences in the growth response of smooth muscle from young and old animals. De novo DNA synthesis as measured by the aphidicolin-sensitive specific activity of DNA was used as an index of cell growth. Compared with old tissue, the rate of aphidicolin-sensitive DNA synthesis in smooth muscle from young animals was 3-5 and 1.5-2 times greater in bladder and taenia coli, respectively. Stretch of bladder muscle and taenia coli strips from young animals for 6 h increased the aphidicolin-sensitive specific activity of DNA 3-fold (P less than 0.01) and 1.5-fold (P less than 0.01), respectively. Tissue from old animals, however, under the same conditions increased the rate of aphidicolin-resistant DNA synthesis, possibly implying DNA repair. Autoradiography showed only labeled myocyte nuclei. These results indicate that homeostatic mechanisms modulating myocyte growth in visceral smooth muscle can respond to mechanical stimulus in the absence of other trophic factors.

scholarly journals PHI-like immunoreactivity in the gallbladder and in vitro effect of porcine PHI on smooth muscle of the gallbladder

FEBS Letters ◽  
1984 ◽  
Vol 175 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Y. Yiangou ◽  
N.D. Christofides ◽  
J. Gu ◽  
P.J. Piper ◽  
J.M. Polak ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vitro Effect

Extravascular sources of lung angiotensin peptide synthesis in idiopathic pulmonary fibrosis

2006 ◽  
Vol 291 (5) ◽  
pp. L887-L895 ◽  
Author(s):  
Xiaopeng Li ◽  
Maria Molina-Molina ◽  
Amal Abdul-Hafez ◽  
Jose Ramirez ◽  
Anna Serrano-Mollar ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Human Lung ◽  
De Novo ◽  
Alveolar Epithelial Cells ◽  
Human Lung Cells ◽  
Normal Human

Previous work from this laboratory demonstrated de novo synthesis of angiotensin (ANG) peptides by apoptotic pulmonary alveolar epithelial cells (AEC) and by lung myofibroblasts in vitro and in bleomycin-treated rats. To determine whether these same cell types also synthesize ANG peptides de novo within the fibrotic human lung in situ, we subjected paraffin sections of normal and fibrotic (idiopathic pulmonary fibrosis, IPF) human lung to immunohistochemistry (IHC) and in situ hybridization to detect ANG peptides and angiotensinogen (AGT) mRNA. These were analyzed both alone and in combination with cell-specific markers of AEC [monoclonal antibody (MAb) MNF-116] and myofibroblasts [α-smooth muscle actin (α-SMA) MAb] and an in situ DNA end labeling (ISEL) method to detect apoptosis. In normal human lung, IHC detected AGT protein in smooth muscle underlying normal bronchi and vessels, but not elsewhere. Real-time RT-PCR and Western blotting revealed that AGT mRNA and protein were 21-fold and 3.6-fold more abundant, respectively, in IPF lung biopsies relative to biopsies of normal human lung (both P < 0.05). In IPF lung, both AGT protein and mRNA were detected in AEC that double-labeled with MAb MNF-116 and with ISEL, suggesting AGT expression by apoptotic epithelia in situ. AGT protein and mRNA also colocalized to myofibroblast foci detected by α-SMA MAb, but AGT mRNA was not detected in smooth muscle. These data are consistent with earlier data from isolated human lung cells in vitro and bleomycin-induced rat lung fibrosis models, and they suggest that apoptotic AEC and myofibroblasts constitute key sources of locally derived ANG peptides in the IPF lung.

scholarly journals Endogenous IGF-I and αvβ3 integrin ligands regulate increased smooth muscle growth in TNBS-induced colitis

2009 ◽  
Vol 296 (6) ◽  
pp. G1230-G1237 ◽  
Author(s):  
Krystina B. Hazelgrove ◽  
Robert S. Flynn ◽  
Li-Ya Qiao ◽  
John R. Grider ◽  
John F. Kuemmerle
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Muscle Cell ◽  
Muscle Growth ◽  
Muscle Cells ◽  
Intestinal Smooth Muscle ◽  
Muscle Hyperplasia ◽  
Igf I ◽  
Integrin Ligands ◽  
Smooth Muscle Hyperplasia

Endogenous insulin-like growth factor-I (IGF-I) regulates intestinal smooth muscle growth by concomitantly stimulating proliferation and inhibiting apoptosis. IGF-I-stimulated growth is augmented by the αvβ3 integrin ligands vitronectin and fibronectin. IGF-I expression in smooth muscle is increased in both TNBS-induced colitis and Crohn's disease. We hypothesized that intestinal inflammation increased vitronectin and fibronectin expression by smooth muscle and, along with IGF-I upregulation, increased intestinal muscle growth. Intestinal smooth muscle cells were examined 7 days following the induction of TNBS-induced colitis. Although αvβ3 integrin expression was not altered by TNBS-induced colitis, vitronectin and fibronectin levels were increased by 80 ± 10% and 90 ± 15%, above control levels, respectively. Basal IGF-I receptor phosphorylation in inflamed muscle from TNBS-treated rats was increased by 86 ± 8% over vehicle-treated controls. Basal ERK1/2, p70S6 kinase, and GSK-3β phosphorylation in muscle cells of TNBS-treated rats were also increased by 140–180%. TNBS treatment increased basal muscle cell proliferation by 130 ± 15% and decreased apoptosis by 20 ± 2% compared with that in vehicle-treated controls. The changes in proliferation and apoptosis were reversed by an IGF-I receptor tyrosine kinase inhibitor or an αvβ3 integrin antagonist. The results suggest that smooth muscle hyperplasia in TNBS-induced colitis partly results from the upregulation of endogenous IGF-I and ligands of αvβ3 integrin that mediate increased smooth muscle cell proliferation and decreased apoptosis. This paper has identified one mechanism regulating smooth muscle hyperplasia, a feature of stricture formation that occurs in the chronically inflamed intestine of TNBS-induced colitis and potentially Crohn's disease.

scholarly journals STUDIES ON THE RIGOR RESULTING FROM THE THAWING OF FROZEN FROG SARTORIUS MUSCLE

1950 ◽  
Vol 33 (5) ◽  
pp. 563-577 ◽  
Author(s):  
S. V. Perry
Keyword(s):  
Hydrogen Peroxide ◽  
Iodoacetic Acid ◽  
Sartorius Muscle ◽  
Fixed Length ◽  
Frog Sartorius Muscle ◽  
Vitro Effect ◽  
Resting Muscle ◽  
Frog Sartorius

1. The rigor which takes place when completely frozen frog sartorius muscle is thawed ("thaw rigor"), is accompanied by a decrease in length of 70 per cent and a loss in weight of 35 per cent, whether the muscle is frozen in the resting or the exhausted condition, or during isometric tetanus. Muscle tetanized to maximal shortening shows a loss in weight of 25 per cent on thawing. 2. A load of 8 gm. is sufficient to prevent the decrease in length on thawing, but after its removal the muscle will shorten almost to the normal extent. 3. Inhibitors such as azide, cyanide, 2:4 dinitrophenol, p-chloromercuribenzoate, Cu, and hydrogen peroxide, when used for periods not exceeding 1 hour, have little effect on the shortening; although in some cases these poisons render the muscle inexcitable. 4. Muscles poisoned with iodoacetic acid and stimulated to exhaustion, or maintained at fixed length in nitrogen, show little or no shortening on thawing. ATP can produce shortening in the muscles in which it has been prevented. 5. The phenomenon is considered to be due to an in situ synaeresis of the actomyosin of the myofibrils. As a result of the disorganisation of the muscle protoplasm produced by the freezing and subsequent thawing, the ATP, which must be bound or localized in the resting muscle, can act on the myofibril in a similar manner to its in vitro effect on the actomyosin thread.

scholarly journals In vitro effects of bethanechol on specimens of intestinal smooth muscle obtained from the duodenum and jejunum of healthy dairy cows

2007 ◽  
Vol 68 (3) ◽  
pp. 313-322 ◽  
Author(s):  
Julia B. R. Pfeiffer ◽  
Meike Mevissen ◽  
Adrian Steiner ◽  
Christopher J. Portier ◽  
Mireille Meylan
Keyword(s):  
Smooth Muscle ◽  
Dairy Cows ◽  
Intestinal Smooth Muscle ◽  
In Vitro Effects

scholarly journals Two microRNAs, miR-330 and miR-125b-5p, mark the juxtaglomerular cell and balance its smooth muscle phenotype

2012 ◽  
Vol 302 (1) ◽  
pp. F29-F37 ◽  
Author(s):  
Silvia Medrano ◽  
Maria C. Monteagudo ◽  
Maria Luisa S. Sequeira-Lopez ◽  
Ellen S. Pentz ◽  
R. Ariel Gomez
Keyword(s):  
Smooth Muscle ◽  
In Situ Hybridization ◽  
In Silico ◽  
Smooth Muscle Actin ◽  
In Silico Analysis ◽  
Screening Strategy ◽  
The Other ◽  
Kidney Cortex

We have shown that microRNAs (miRNAs) are necessary for renin cell specification and kidney vascular development. Here, we used a screening strategy involving microarray and in silico analyses, along with in situ hybridization and in vitro functional assays to identify miRNAs important for renin cell identity. Microarray studies using vascular smooth muscle cells (SMCs) of the renin lineage and kidney cortex under normal conditions and after reacquisition of the renin phenotype revealed that of 599 miRNAs, 192 were expressed in SMCs and 234 in kidney cortex. In silico analysis showed that the highly conserved miR-330 and miR-125b-5p have potential binding sites in smoothelin ( Smtn), calbindin 1, smooth muscle myosin heavy chain, α-smooth muscle actin, and renin genes important for the myoepithelioid phenotype of the renin cell. RT-PCR studies confirmed miR-330 and miR-125b-5p expression in kidney and SMCs. In situ hybridization revealed that under normal conditions, miR-125b-5p was expressed in arteriolar SMCs and in juxtaglomerular (JG) cells. Under conditions that induce reacquisition of the renin phenotype, miR-125b-5p was downregulated in arteriolar SMCs but remained expressed in JG cells. miR-330, normally absent, was expressed exclusively in JG cells of treated mice. In vitro functional studies showed that overexpression of miR-330 inhibited Smtn expression in SMCs. On the other hand, miR-125b-5p increased Smtn expression, whereas its inhibition reduced Smtn expression. Our results demonstrate that miR-330 and miR-125b-5p are markers of JG cells and have opposite effects on renin lineage cells: one inhibiting and the other favoring their smooth muscle phenotype.

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