Extracellular ciliary axonemes associated with the surface of smooth muscle cells of ctenophores

1989 ◽  
Vol 94 (4) ◽  
pp. 713-724
Author(s):  
S. Tamm ◽  
S.L. Tamm

We describe the first example of bare ciliary axonemes existing outside eukaryotic cells. The axonemes run in longitudinal invaginations of the surface membrane of giant smooth muscle cells in ctenophores. No motility of the surface-associated axonemes has been detected in living muscles. The axonemes are truly extracellular and in direct contact with the extracellular matrix (mesoglea), as shown by the ultrastructural tracer horseradish peroxidase. The axonemes appear partially degraded and disorganized, and individual doublet microtubules are difficult to distinguish. Nevertheless, immunofluorescence microscopy shows that the axonemes retain antigenic sites reacting with mouse monoclonal anti-beta-tubulin. The origin of the extracellular axonemes is unknown: no attached basal bodies (extracellular or intracellular) have been found. The muscle-associated axonemes may play a unique role in smooth muscle function and/or development, and may be related to the evolution of muscle cells in soft-bodied invertebrates that exploit cilia for a wide variety of functions.

2012 ◽  
Vol 425 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Koji Ikeda ◽  
Yuka Souma ◽  
Yoshiki Akakabe ◽  
Youhei Kitamura ◽  
Kiyonari Matsuo ◽  
...  

2003 ◽  
Vol 285 (5) ◽  
pp. C1330-C1338 ◽  
Author(s):  
M. Sajid ◽  
R. Zhao ◽  
A. Pathak ◽  
S. S. Smyth ◽  
G. A. Stouffer

αvβ3-Integrin antagonists reduced neointimal formation following vascular injury in eight different animal models. Because α-thrombin contributes to neointimal formation, we examined the hypothesis that αvβ3-integrins influence α-thrombin-induced signaling. Cultured rat aortic smooth muscle cells (RASMC) expressed αvβ3-integrins as demonstrated by immunofluorescence microscopy and fluorescence-activated cell sorting analysis. Proliferative responses to α-thrombin were partially inhibited by anti-β3-integrin monoclonal antibody F11 and by cyclic RGD peptides. Immunofluorescence microscopy showed that α-thrombin stimulated a rapid increase in the formation of focal adhesions as identified by vinculin staining and that this effect was partially inhibited by αvβ3 antagonists. β3-Integrin staining was diffuse in quiescent RASMC and did not concentrate at sites of focal adhesions following thrombin treatment. α-Thrombin elicited a time-dependent increase in activation of c-Jun NH2-terminal kinase-1 (JNK1) and in tyrosine phosphorylation of focal adhesion kinase (FAK). αvβ3-Integrin antagonists partially inhibited increases in JNK1 activity but had no effect on FAK phosphorylation. In SMC isolated from β3-integrin-deficient mice, focal adhesion formation was impaired in response to thrombin but not sphingosine-1-phosphate, a potent activator of Rho. In summary, αvβ3-integrins play an important role in α-thrombin-induced proliferation and focal adhesion formation in RASMC.


1980 ◽  
Vol 84 (3) ◽  
pp. 633-654 ◽  
Author(s):  
W W Franke ◽  
E Schmid ◽  
C Freudenstein ◽  
B Appelhans ◽  
M Osborn ◽  
...  

Myoepithelial cells from mammary glands, the modified sweat glands of bovine muzzle, and salivary glands have been studied by electron microscopy and by immunofluorescence microscopy in frozen sections in an attempt to further characterize the type of intermediate-sized filaments present in these cells. Electron microscopy has shown that all myoepithelial cells contain extensive meshworks of intermediate-sized (7--11-nm) filaments, many of which are anchored at typical desmosomes or hemidesmosomes. The intermediate-sized filaments are also intimately associated with masses of contractile elements, identified as bundles of typical 5--6-nm microfilaments and with characteristically spaced dense bodies. This organization resembles that described for various smooth muscle cells. In immunofluorescence microscopy, using antibodies specific for the various classes of intermediate-sized filaments, the myoepithelial cells are strongly decorated by antibodies to prekeratin. They are not specifically stained by antibodies to vimentin, which stain mesenchymal cells, nor by antibodies to chick gizzard desmin, which decorate fibrils in smooth muscle Z bands and intercalated disks in skeletal and cardiac muscle of mammals. Myoepithelial cells are also strongly stained by antibodies to actin. The observations show (a) that the epithelial character, as indicated by the presence of intermediate-sized filaments of the prekeratin type, is maintained in the differentiated contractile myoepithelial cell, and (b) that desmin and desmin-containing filaments are not generally associated with musclelike cell specialization for contraction but are specific to myogenic differentiation. The data also suggest that in myoepithelial cells prekeratin filaments are arranged--and might function--in a manner similar to the desmin filaments in smooth muscle cells.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Abhijit Ghosh ◽  
Angela Pechota ◽  
Dawn Coleman ◽  
Gilbert R Upchurch ◽  
Jonathan L Eliason

Introduction Cigarette smoke has a strong correlation with abdominal aortic aneurysm (AAA) formation and is characterized by increased levels of MMP9 in the aorta. We hypothesized that smoke-induced MMP9 regulation is mediated by the Jak/Stat pathway thereby contributing to AAA formation. Methods Aqueous extract of cigarette smoke (AEC) was applied to male rat aortic vascular smooth muscle cells (RASMC) for 24 hours (h) in serum free medium (SFM), using SFM alone for controls. Media were collected for MMP2 and MMP9 zymography and proteins extracted from cells for phospho-Stat3 (pStat3), total Stat3 (T-Stat3), phospho-Jak2 (pJak2) and total Jak2 (T-Jak2) western blots. RASMC were transfected by siRNAs for Jak2 and Stat3 before AEC treatment to evaluate induction of MMPs. Coimmunoprecipitation and immunofluorescence microscopy investigated complex formation and cellular distribution of Jak2 and Stat3 following AEC treatment. Results MMP9 was increased in the medium of the AEC treated RASMC (P=0.005) and pro-MMP2 slightly elevated (P=0.055) at 24h compared to controls. By western blot protein extracts from AEC treated RASMC showed up regulation of pStat3, pJak2 and T-Jak2 and stable T-Stat3 compared with controls. siRNA transfection of RASMC for Jak2, Stat3 and a combination of Jak2 and Stat3 reduced MMP9 (P<0.005) and pro-MMP2 (P<0.05) in medium of AEC treated RASMC compared with AEC-treated cells transfected with control siRNA. Coimmunoprecipitation of total proteins from RASMC with total Jak2 antibody revealed increased levels of pStat3 in the AEC treated cells compared to controls, while separation of nuclear and cytoplasmic components followed by coimmunoprecipitation revealed more abundant Jak2/T-Stat3 complexes in the nuclear fraction than the cytoplasm following AEC treatment. Immunofluorescence microscopy revealed increased presence of pJak2, T-Jak2, pStat3 and T-Stat3 in the cytoplasm and nucleus of the AEC treated cells compared to the control cells. Conclusion This study suggests that cigarette smoke may result in AAA formation through Jak/Stat-mediated MMP9 production. siRNA inhibition of the Jak/Stat pathway greatly reduced AEC-induced MMP9 by RASMC and suggests a potential therapeutic target for the treatment of AAA.


1997 ◽  
Vol 8 (4) ◽  
pp. 663-673 ◽  
Author(s):  
K Murata ◽  
K Hirano ◽  
E Villa-Moruzzi ◽  
D J Hartshorne ◽  
D L Brautigan

Myosin II light chains (MLC20) are phosphorylated by a Ca2+/calmodulin-activated kinase and dephosphorylated by a phosphatase that has been purified as a trimer containing the delta isoform of type 1 catalytic subunit (PP1C delta), a myosin-binding 130-kDa subunit (M130) and a 20-kDa subunit. The distribution of M130 and PP1C as well as myosin II was examined in smooth muscle cells and fibroblasts by immunofluorescence microscopy and immunoblotting after differential extraction. Myosin and M130 colocalized with actin stress fibers in permeabilized cells. However, in nonpermeabilized cells the staining for myosin and M130 was different, with myosin mostly at the periphery of the cell and the M130 appearing diffusely throughout the cytoplasm. Accordingly, most M130 was recovered in a soluble fraction during permeabilization of cells, but the conditions used affected the solubility of both M130 and myosin. The PP1C alpha isoform colocalized with M130 and also was in the nucleus, whereas the PP1C delta isoform was localized prominently in the nucleus and in focal adhesions. In migrating cells, M130 concentrated in the tailing edge and was depleted from the leading half of the cell, where double staining showed myosin II was present. Because the tailing edge of migrating cells is known to contain phosphorylated myosin, inhibition of myosin LC20 phosphatase, probably by phosphorylation of the M130 subunit, may be required for cell migration.


2003 ◽  
Vol 94 (4) ◽  
pp. 1596-1601 ◽  
Author(s):  
Lynn M. Iwamoto ◽  
Kenneth T. Nakamura ◽  
Randal K. Wada

Inhibition of the Na-K-2Cl (NKCC) cotransporter by loop diuretics is associated with airway relaxation, but there has been no direct evidence for the expression of this protein in airway smooth muscle. Thus we hypothesized that a NKCC cotransporter is present and functional in airway smooth muscle cells. Monoclonal and polyclonal antibodies were used first to demonstrate the presence of a NKCC cotransporter protein in isolated human fetal trachea and normal human bronchial smooth muscle cells (BSMC) by Western blotting. The cotransporter protein was then localized by immunohistochemical staining to airway smooth muscle cells in culture and in situ. The localization was confirmed by indirect immunofluorescence and laser confocal microscopy in the BSMC. Cotransporter function in BSMC was also confirmed in vitro by bumetanide-mediated inhibition of rubidium uptake. Our present findings thus document the presence of a functional NKCC cotransporter in human airway smooth muscle, providing a basis for defining the role of this ion cotransporter in airway smooth muscle function.


1994 ◽  
Vol 104 (2) ◽  
pp. 395-422 ◽  
Author(s):  
A Guerrero ◽  
J J Singer ◽  
F S Fay

Activation of ryanodine receptors on the sarcoplasmic reticulum of single smooth muscle cells from the stomach muscularis of Bufo marinus by caffeine is accompanied by a rise in cytoplasmic [Ca2+] ([Ca2+]i), and the opening of nonselective cationic plasma membrane channels. To understand how each of these pathways contributes to the rise in [Ca2+]i, one needs to separately monitor Ca2+ entry through them. Such information was obtained from simultaneous measurements of ionic currents and [Ca2+]i by the development of a novel and general method to assess the fraction of current induced by an agonist that is carried by Ca2+. Application of this method to the currents induced in these smooth muscle cells by caffeine revealed that approximately 20% of the current passing through the membrane channels activated following caffeine application is carried by Ca2+. Based on this information we found that while Ca2+ entry through these channels rises slowly, release of Ca2+ from stores, while starting at the same time, is much faster and briefer. Detailed quantitative analysis of the Ca2+ release from stores suggests that it most likely decays due to depletion of Ca2+ in those stores. When caffeine was applied twice to a cell with only a brief (30 s) interval in between, the amount of Ca2+ released from stores was markedly diminished following the second caffeine application whereas the current carried in part by Ca2+ entry across the plasma membrane was not significantly affected. These and other studies described in the preceding paper indicate that activation of the nonselective cation plasma membrane channels in response to caffeine was not caused as a consequence of emptying of internal Ca2+ stores. Rather, it is proposed that caffeine activates these membrane channels either by direct interaction or alternatively by a linkage between ryanodine receptors on the sarcoplasmic reticulum and the nonselective cation channels on the surface membrane.


2020 ◽  
Vol 319 (1) ◽  
pp. H42-H50 ◽  
Author(s):  
Zoltan Nemeth ◽  
Emily Hildebrandt ◽  
Michael J. Ryan ◽  
Joey P. Granger ◽  
Heather A. Drummond

Pressure-induced, but not agonist-induced, vasoconstriction is abolished in the middle cerebral artery (MCA) of TrpC6 null mice. TrpC6 localization in dissociated cerebral vascular smooth muscle cells is primarily cytoplasmic and not associated with the surface membrane where a mechanoelectrical coupler might be expected. These findings suggest that TrpC6 is required for transduction of pressure-induced constriction in the MCA; however, its role as a mechanoelectrical coupler or downstream signal amplifier remains unresolved.


Author(s):  
J.M. Minda ◽  
E. Dessy ◽  
G. G. Pietra

Pulmonary lymphangiomyomatosis (PLAM) is a rare disease occurring exclusively in women of reproductive age. It involves the lungs, lymph nodes and lymphatic ducts. In the lungs, it is characterized by the proliferation of smooth muscle cells around lymphatics in the bronchovascular bundles, lobular septa and pleura The nature of smooth muscle proliferation in PLAM is still unclear. Recently, reactivity of the smooth muscle cells for HMB-45, a melanoma-related antigen has been reported by immunohistochemistry. The purpose of this study was the ultrastructural localization of HMB-45 immunoreactivity in these cells using gold-labeled antibodies.Lung tissue from three cases of PLAM, referred to our Institution for lung transplantation, was embedded in either Poly/Bed 812 post-fixed in 1% osmium tetroxide, or in LR White, without osmication. For the immunogold technique, thin sections were placed on Nickel grids and incubated with affinity purified, monoclonal anti-melanoma antibody HMB-45 (1:1) (Enzo Diag. Co) overnight at 4°C. After extensive washing with PBS, grids were treated with Goat-anti-mouse-IgG-Gold (5nm) (1:10) (Amersham Life Sci) for 1 hour, at room temperature.


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