cFKBP/SMAP; a novel molecule involved in the regulation of smooth muscle differentiation

Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3535-3542 ◽  
Author(s):  
K. Fukuda ◽  
Y. Tanigawa ◽  
G. Fujii ◽  
S. Yasugi ◽  
S. Hirohashi

During embryogenesis, smooth muscle cells of the gut differentiate from mesenchymal cells derived from splanchnic mesoderm. We have isolated a gene involved in the differentiation of smooth muscle cells in the gut using differential display between the chicken proventriculus in which the smooth muscle layer develops poorly and the gizzard in which smooth muscles develop abundantly. The protein encoded by this gene showed highest similarity to mouse FK506 binding protein, FKBP65, and from the function of this protein it was designated chicken FKBP/smooth muscle activating protein (cFKBP/SMAP). cFKBP/SMAP was first expressed in smooth muscle precursor cells of the gut and, after smooth muscles differentiate, expression was restricted to smooth muscle cells. In organ culture of the gizzard, the differentiation of smooth muscle cells was inhibited by the addition of FK506, the inhibitor of FKBPs. Moreover, overexpression of cFKBP/SMAP in lung and gizzard mesenchymal cells induced smooth muscle differentiation. In addition, cFKBP/SMAP-induced smooth muscle differentiation was inhibited by FK506. We postulate therefore that cFKBP/SMAP plays a crucial role in smooth muscle differentiation in the gut and provides a powerful tool to study smooth muscle differentiation mechanisms, which have been poorly analyzed so far.

Blood ◽  
1993 ◽  
Vol 82 (1) ◽  
pp. 66-76 ◽  
Author(s):  
MC Galmiche ◽  
VE Koteliansky ◽  
J Briere ◽  
P Herve ◽  
P Charbord

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle- specific actin isoforms. The present study was carried out to evaluate the time course of alpha-SM-positive stromal cells and to search for other cytoskeletal proteins specific for smooth muscle cells. It was found that the expression of alpha-SM in stromal cells was time dependent. Most of the adherent spindle-shaped, vimentin-positive stromal cells observed during the first 2 weeks of culture were alpha- SM negative. On the contrary, from week 3 to week 7, most interdigitated stromal cells contained stress fibers whose backbone was made of alpha-SM-positive microfilaments. In addition, in confluent cultures, other proteins specific for smooth muscle were detected: metavinculin, h-caldesmon, smooth muscle myosin heavy chains, and calponin. This study confirms the similarity between stromal cells and smooth muscle cells. Moreover, our results reveal that cells in vivo with the phenotype closest to that of stromal cells are immature fetal smooth muscle cells and subendothelial intimal smooth muscle cells; a cell subset with limited development following birth but extensively recruited in atherosclerotic lesions. Stromal cells very probably derive from mesenchymal cells that differentiate along this distinctive vascular smooth muscle cell pathway. In humans, this differentiation seems crucial for the maintenance of granulomonopoiesis. These in vitro studies were completed by examination of trephine bone marrow biopsies from adults without hematologic abnormalities. These studies revealed the presence of alpha-SM-positive cells at diverse locations: vascular smooth muscle cells in the media of arteries and arterioles, pericytes lining capillaries, myoid cells lining sinuses at the abluminal side of endothelial cells or found within the hematopoietic logettes, and endosteal cells lining bone trabeculae. More or less mature cells of the granulocytic series were in intimate contact with the thin cytoplasmic extensions of myoid cells. Myoid cells may be the in vivo counterpart of stromal cells with the above-described vascular smooth muscle phenotype.


2018 ◽  
Vol 125 (4) ◽  
pp. 1090-1096 ◽  
Author(s):  
Alan L. James ◽  
Peter B. Noble ◽  
Su-Ann Drew ◽  
Thais Mauad ◽  
Tony R. Bai ◽  
...  

In asthma, it is unclear if the airway smooth muscle cells proliferate more or are increased at the onset of asthma and remain stable. This study aimed to compare smooth muscle cell proliferation in individuals with and without asthma and correlate proliferation rates with cell size and number and with granulocytic airway inflammation. Postmortem airway sections were labeled with proliferating cell nuclear antigen (PCNA) and percent positive muscle cells calculated. On the same sections, smooth muscle cell size and number and the number of eosinophils and neutrophils were estimated and compared in cases of nonfatal ( n = 15) and fatal ( n = 15) asthma and control subjects ( n = 15). The %PCNA+ muscle cells was not significantly different in fatal (29.4 ± 7.7%, mean ± SD), nonfatal asthma (28.6 ± 8.3%), or control subjects (24.6 ± 6.7%) and not related to mean muscle cell size ( r = 0.09), number ( r = 0.36), thickness of the muscle layer ( r = 0.05), or eosinophil numbers ( r = 0.04) in the asthma cases. These data support the hypothesis that in asthma the increased thickness of the smooth muscle layer may be present before or at the onset of asthma and independent of concurrent granulocytic inflammation or exacerbation. NEW & NOTEWORTHY There is debate regarding the origins of the increased airway smooth muscle in asthma. It may be independent of inflammation or arise as a proliferative response to inflammation. The present study found no increase in the proportion of proliferating smooth muscle cells in asthma and no relation of proliferation to numbers of airway smooth muscle cells or inflammation. These results support a stable increase in smooth muscle in asthma that is independent of airway inflammation.


2003 ◽  
Vol 127 (11) ◽  
pp. 1513-1516 ◽  
Author(s):  
Lizhen Gui ◽  
Steven A. Bigler ◽  
Charu Subramony

Abstract Pancreatic lymphangiomas, which occur predominantly in women, are rare and account for only 1% of all lymphangiomas. The characteristic histologic features include multiple cysts lined by endothelial cells, irregularly distributed smooth muscle cells, and lymphoid aggregates in the wall of the cyst. We describe a 36-year-old woman with lymphangioma of the pancreas with “ovarian-like” mesenchymal stroma in the wall. This stroma, composed of uncommitted mesenchymal cells, has not been described previously in the wall of pancreatic lymphangiomas. Multiple small lymphatic channels that are found in this stroma recapitulate the development of lymphatic channels in the embryo. Lymphangioma of the pancreas may arise from distension of these lymphatic channels. Pancreatic lymphangioma may, therefore, be a developmental anomaly rather than a true neoplasm.


1988 ◽  
Vol 254 (1) ◽  
pp. C45-C52 ◽  
Author(s):  
K. Sumimoto ◽  
M. Hirata ◽  
H. Kuriyama

Specific binding of the dihydropyridine Ca2+ antagonist [3H]nifedipine to dispersed smooth muscle cells of the porcine coronary artery was investigated and the findings were compared with the binding to microsomes of smooth muscles. Specific binding to intact cells was saturable and reversible. The dissociation constant was 1.93 +/- 0.42 nM and the maximal binding capacity was 59.6 +/- 12.4 fmol/10(6) cells, as assessed by Scatchard analysis of the equilibrium binding at 25 degrees C. The Kd value with intact cells was slightly higher than that observed with microsomes. Specific binding of [3H]nifedipine to intact cells was completely displaced by unlabeled dihydropyridine derivatives. Among other Ca2+ antagonists, verapamil and d-cis-diltiazem partially and flunarizine completely inhibited the binding. In the case of microsomes, d-cis-diltiazem stimulated the binding of [3H]nifedipine. These results suggest that there may be multiple binding sites for different subclasses of Ca2+ antagonists. Polyvalent cations had no effect on the binding to intact cells. In the case of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-treated microsomes, the addition of CaCl2 and BaCl2 increased the Bmax, but the Kd value remained unchanged. MnCl2 and CdCl2 had stimulatory or inhibitory effects, depending on the concentrations, whereas LaCl3 had no effect. The effect of membrane depolarization on the binding was also examined. When the intact cells were incubated in high [K+]o solution for 60 min, the Kd was lowered to 1.4 nM from the control value of 2.0 nM, thereby indicating that [3H]nifedipine binds to Ca2+ channels, with a higher affinity, at depolarized states.


1999 ◽  
Vol 277 (1) ◽  
pp. G127-G136 ◽  
Author(s):  
Anne Epperson ◽  
Helena P. Bonner ◽  
Sean M. Ward ◽  
William J. Hatton ◽  
Karri K. Bradley ◽  
...  

Voltage-activated K+(KV) channels play an important role in regulating the membrane potential in excitable cells. In gastrointestinal (GI) smooth muscles, these channels are particularly important in modulating spontaneous electrical activities. The purpose of this study was to identify the molecular components that may be responsible for the KV currents found in the canine GI tract. In this report, we have examined the qualitative expression of eighteen different KV channel genes in canine GI smooth muscle cells at the transcriptional level using RT-PCR analysis. Our results demonstrate the expression of KV1.4, KV1.5, KV1.6, KV2.2, and KV4.3 transcripts in all regions of the GI tract examined. Transcripts encoding KV1.2, KVβ1.1, and KVβ1.2 subunits were differentially expressed. KV1.1, KV1.3, KV2.1, KV3.1, KV3.2, KV3.4, KV4.1, KV4.2, and KVβ2.1 transcripts were not detected in any GI smooth muscle cells. We have also determined the protein expression for a subset of these KV channel subunits using specific antibodies by immunoblotting and immunohistochemistry. Immunoblotting and immunohistochemistry demonstrated that KV1.2, KV1.4, KV1.5, and KV2.2 are expressed at the protein level in GI tissues and smooth muscle cells. KV2.1 was not detected in any regions of the GI tract examined. These results suggest that the wide array of electrical activity found in different regions of the canine GI tract may be due in part to the differential expression of KV channel subunits.


2001 ◽  
Vol 149 (23) ◽  
pp. 707-711 ◽  
Author(s):  
N. P. H. Hudson ◽  
I. G. Mayhew ◽  
G. T. Pearson

Intracellular microelectrode recordings were made from smooth muscle cells in cross-sectional preparations of equine ileum, superfused in vitro. Membrane potential oscillations and spike potentials were recorded in all preparations, but recordings were made more readily from cells in the longitudinal muscle layer than from cells in the circular layer. The mean (se) resting membrane potential (RMP) of smooth muscle cells in the longitudinal muscle layer was -51.9 (1.2) mV, and the membrane potential oscillations in this layer had a mean amplitude of 4.8 (0.4) mV, a frequency of 9.0 (0.1) cycles per minute and a duration of 5.8 (0.2) seconds. The membrane potential oscillations were preserved in the presence of tetrodotoxin. A waxing and waning pattern of membrane potential oscillation activity was observed. Nifedipine abolished the spiking contractile activity of the smooth muscle, did not abolish the membrane potential oscillations but did alter their temporal characteristics.


2003 ◽  
Vol 284 (3) ◽  
pp. H1018-H1027 ◽  
Author(s):  
Nari Kim ◽  
Jin Han ◽  
Euiyong Kim

Although PGF2αaffects contractility of vascular smooth muscles, no studies to date have addressed the electrophysiological mechanism of this effect. The purpose of our investigation was to examine the direct effects of PGF2α on membrane potentials, Ca2+-activated K+ (KCa) channels, delayed rectifier K+ (KV) channels, and L-type Ca2+channels with the patch-clamp technique in single rabbit middle cerebral arterial smooth muscle cells (SMCs). PGF2αsignificantly hyperpolarized membrane potentials and increased the amplitudes of total K+ currents. PGF2αincreased open-state probability but had little effect on the open and closed kinetics of KCa channels. PGF2αincreased the amplitudes of KV currents with a leftward shift of the activation and inactivation curves and a decrease in the activation time constant. PGF2α decreased the amplitudes of L-type Ca2+ currents without any significant change in threshold or apparent reversal potentials. This study provides the first finding that the direct effects of PGF2α on middle cerebral arterial SMCs, at least in part, could attenuate vasoconstriction.


2014 ◽  
Vol 94 (3) ◽  
pp. 859-907 ◽  
Author(s):  
Kenton M. Sanders ◽  
Sean M. Ward ◽  
Sang Don Koh

Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα+cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα+cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.


One of the earliest studies on the physiology of smooth muscle was that reported by Engelmann over 100 years ago. In setting the stage for this discussion on new developments in smooth muscle physiology, Professor Bozler recalled Engelmann’s description of the ureter as a ‘giant hollow muscle fibre’. Recent work on the passive electrical properties of smooth muscle has shown that Engelmann’s concept of the syncytial behaviour of smooth muscle is true for a great many smooth muscles - perhaps for all vertebrate smooth muscles. When smooth muscle cells come into contact they interact with each other so as to form a tissue. In this sense, a community of smooth muscle cells is analogous with the liver, epithelial tissues and the heart. One can contrast this ‘collective’ behaviour of smooth muscle cells with the separate identity maintained by most nerve cells and skeletal muscle fibres.


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