Retardation of Phenotypic Transition of Rabbit Arterial Smooth Muscle Cells in Three-Dimensional Primary Culture

1996 ◽  
Vol 225 (1) ◽  
pp. 12-21 ◽  
Author(s):  
Mari Yamamoto ◽  
Hiroaki Nakamura ◽  
Masayuki Yamato ◽  
Masaru Aoyagi ◽  
Kiyotaka Yamamoto
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Primary Culture ◽  
Three Dimensional ◽  
Muscle Cells ◽  
Arterial Smooth Muscle ◽  
Arterial Smooth Muscle Cells ◽  
Phenotypic Transition

scholarly journals Diverse effects of fibronectin and laminin on phenotypic properties of cultured arterial smooth muscle cells.

1988 ◽  
Vol 107 (1) ◽  
pp. 307-319 ◽  
Author(s):  
U Hedin ◽  
B A Bottger ◽  
E Forsberg ◽  
S Johansson ◽  
J Thyberg
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Primary Culture ◽  
Muscle Cells ◽  
Plasma Fibronectin ◽  
Arterial Smooth Muscle ◽  
Rna And Protein Synthesis ◽  
Arterial Smooth Muscle Cells ◽  
Synthetic Phenotype ◽  
Cells Cultured

Plasma fibronectin promotes modulation of rat arterial smooth muscle cells from a contractile to a synthetic phenotype during the first few days in primary culture. This process includes cell adhesion and spreading, loss of myofilaments, and formation of a widespread rough endoplasmic reticulum and a prominent Golgi complex. The structural reorganization is accompanied by activation of overall RNA and protein synthesis. Moreover, the cells gain the ability to replicate their DNA and divide in response to platelet-derived growth factor. Here, it is demonstrated that the power of fibronectin to bring about this change in the differentiated properties of the smooth muscle cells resides in a 105-kD cell-binding fragment, whereas a 70-kD collagen-binding fragment and a 31-kD heparin-binding fragment are inactive in this respect. Laminin, another adhesive glycoprotein and a component of the basement membrane that normally surrounds arterial smooth muscle, was contrarily found to maintain the cells in a contractile phenotype. However, with increasing time more and more cells went through the modulation into a synthetic phenotype. This "catch-up" was counteracted by a peptide that contained the cell-attachment sequence of fibronectin (Arg-Gly-Asp-Ser). Hence, it is possible that the delayed modulation on laminin was due to production of fibronectin by the cells themselves. In support of this notion, fibronectin isolated from smooth muscle cultures was found to be as effective as plasma fibronectin in stimulating the phenotypic modulation. Moreover, using a combination of chemical, immunochemical, and immunocytochemical methods, it was demonstrated that the cells secreted fibronectin as well as laminin at an increasing rate during the first 4 d in primary culture and, notably, cells cultured on laminin produced more fibronectin than cells cultured on fibronectin. Newly synthesized fibronectin was incorporated into a network of pericellular and intercellular fibrils, whereas laminin formed a more diffuse layer covering the cells in a basement membrane-like manner. Taken together, the findings suggest diverse roles for fibronectin and laminin in the control of the differentiated properties of arterial smooth muscle cells. They further indicate that the ability of arterial smooth muscle cells to produce fibronectin and laminin early in primary culture is not directly related to the phenotypic state as determined morphologically and by measurement of overall rates of RNA and protein synthesis. This may be due to the cells being able to sense the macromolecular composition of the pericellular matrix and to modify their secretory activity accordingly.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of leukotrienes on phenotypic properties and growth of arterial smooth muscle cells in primary culture

1989 ◽  
Vol 93 (3) ◽  
pp. 403-408
Author(s):  
L. Palmberg ◽  
H.E. Claesson ◽  
J. Thyberg
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Primary Culture ◽  
Muscle Cells ◽  
Cell Counting ◽  
Arterial Smooth Muscle ◽  
Serum Free ◽  
Extracellular Matrix Components ◽  
Arterial Smooth Muscle Cells ◽  
Synthetic Phenotype

During the first few days in primary culture arterial smooth muscle cells (SMCs) go through a transition from a contractile to a synthetic phenotype. Morphologically, this process includes loss of myofilaments and formation of an extensive rough endoplasmic reticulum and a large Golgi complex. Functionally, it leads to the cells losing their contractility, beginning to secrete extracellular matrix components, and dividing in response to growth factor stimulation. Similar changes in the structure and function of the SMCs occur in the initial stages of atherogenesis. The object of the present investigation was to study the effects of leukotrienes on the differentiated properties and growth of rat aortic SMCs in primary culture. Enzymically isolated cells were seeded directly on a plastic surface in serum-containing medium or on a substratum of plasma fibronectin in serum-free medium. The change in cell morphology was followed by transmission electron microscopy, and the activation of cell growth by thymidine autoradiography and cell counting. The results demonstrate that 10 pM-LTB4, -LTC4, -LTD4 and -LTE4 all speeded up the shift of the SMCs into a synthetic phenotype, whereas 5S,12S-DHETE (an isomer of LTB4) lacked effect. Further, LTB4, LTC4 and LTD4 stimulated the SMCs to enter the cell cycle earlier than in the controls, enhanced the proliferative response to serum mitogens, and under serum-free conditions induced DNA synthesis by themselves. Indomethacin did not interfere with the effect of LTB4 on the structural transformation of the cells but blocked its effect on DNA replication, suggesting that only the latter involved endogenous production of a cyclo-oxygenase product.(ABSTRACT TRUNCATED AT 250 WORDS)

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