Pulmonary vascular smooth muscle: biochemical and mechanical developmental changes

1991 ◽  
Vol 71 (3) ◽  
pp. 1129-1135 ◽  
Author(s):  
J. Belik ◽  
A. Halayko ◽  
K. Rao ◽  
N. Stephens
Keyword(s):  
Mechanical Properties ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Protein Content ◽  
Second Generation ◽  
Muscle Protein ◽  
Developmental Changes ◽  
Cell Protein ◽  
Fetal Sheep ◽  
Adult Sheep

To evaluate the developmental changes in pulmonary vascular smooth muscle contractile protein content, mechanical properties, and their contribution to the high resistance characteristic of the fetal and immediate neonatal period, we studied pulmonary vessels of fetal, newborn, and adult sheep, as well as newborn and adult pigs. Strips of the second- through fifth-generation vessels were dissected, and their content of tissue total smooth muscle cell protein, myosin, and actin-to-myosin ratio were measured; the mechanical properties of the second-generation vascular strips were also studied. For all ages the smooth muscle protein and myosin content of the second-generation vessels were significantly greater than for the lower pulmonary vascular orders (P less than 0.05). The myosin content in fetal sheep (0.77 +/- 0.03 micrograms/mg wet tissue) was similar to that of the newborn (0.79 +/- 0.04) and adult (0.86 +/- 0.05). However, the smooth muscle protein content (7.94 +/- 0.21 micrograms/mg wet tissue) and the actin-to-myosin ratio of the pulmonary vascular tissue of the fetus (1.00 +/- 0.04) were lower (P less than 0.01) in the fetal than in the newborn (9.16 +/- 0.26 and 1.60 +/- 0.12) and adult (9.38 +/- 0.3 and 1.60 +/- 0.11, respectively). No differences were observed for these parameters between the newborn and adult pig. Stress (16.5 +/- 1.7 mN/mm2) and the maximum shortening capacity (13.0 +/- 1.5% of optimal length) in the newborn pulmonary vascular strips were significantly greater than for the fetus (6.8 +/- 1.4 and 5.9 +/- 1.0, respectively) but similar to those of the adult sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 beta alters actin expression and inhibits contraction of rat thoracic aorta

1992 ◽  
Vol 262 (4) ◽  
pp. C828-C833 ◽  
Author(s):  
L. A. Trinkle ◽  
D. Beasley ◽  
R. S. Moreland
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Protein Content ◽  
Muscle Activation ◽  
Smooth Muscle Actin ◽  
Interleukin 1 ◽  
Contractile Protein ◽  
Interleukin 1 Beta ◽  
Alpha Smooth Muscle Actin ◽  
Mlc Phosphorylation

Previous studies have indicated that interleukin-1 beta (IL-1) inhibits contraction of rat aortas by activating nitric oxide production in vascular smooth muscle cells, with subsequent increases in guanosine 3',5'-cyclic monophosphate (cGMP). This study determined if the effect of IL-1 involves the primary regulatory event in smooth muscle activation, myosin light chain (MLC) phosphorylation. This study also examined whether IL-1 affects contractile protein content. IL-1 (20 ng/ml) significantly decreased stress in response to 0.1 microM phenylephrine with a concomitant decrease in MLC phosphorylation. Incubation with IL-1 for 3 h or longer decreased alpha-smooth muscle actin and increased gamma-actin isoform, with no change in beta-nonmuscle actin or myosin isozyme content. These results suggest that IL-1 inhibition of a vascular smooth muscle contraction may be due to a decrease in activator calcium, which may account for the resultant decrease in MLC phosphorylation. These results also indicate that IL-1 significantly affects contractile protein content, enhancing gamma-actin isoforms and decreasing the vascular smooth muscle specific alpha-isoactin.

A role for PYK2 in ANG II-dependent regulation of the PHAS-1-eIF4E complex by multiple signaling cascades in vascular smooth muscle

2003 ◽  
Vol 285 (6) ◽  
pp. C1437-C1444 ◽  
Author(s):  
Petra Rocic ◽  
Hanjoong Jo ◽  
Pamela A. Lucchesi
Keyword(s):  
Protein Synthesis ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Recombinant Adenovirus ◽  
Pi3 Kinase ◽  
Dominant Negative ◽  
Initiation Factor ◽  
Cell Protein ◽  
Ang Ii ◽  
Tyrosine Kinase 2

Regulation of the PHAS-1-eukaryotic initiation factor-4E (eIF4E) complex is the rate-limiting step in the initiation of protein synthesis. This study characterized the upstream signaling pathways that mediate ANG II-dependent phosphorylation of PHAS-1 and eIF4E in vascular smooth muscle. ANG II-dependent PHAS-1 phosphorylation was maximal at 10 min (2.47 ± 0.3 fold vs. control). This effect was completely blocked by the specific inhibitors of phosphatidylinositol 3-kinase (PI3-kinase, LY-294002), mammalian target of rapamycin, and extracellular signal-regulated kinase 1/2 (ERK1/2, U-0126) or by a recombinant adenovirus encoding dominant-negative Akt. PHAS-1 phosphorylation was followed by dissociation of eIF4E. Increased ANG II-induced eIF4E phosphorylation was observed at 45 min (2.63 ± 0.5 fold vs. control), was maximal at 90 min (3.38 ± 0.3 fold vs. control), and was sustained at 2 h. This effect was blocked by inhibitors of the ERK1/2 and p38 mitogen-activated protein (MAP) kinase pathways, but not by PI3-kinase inhibition, and was dependent on PKC, intracellular Ca2+, and tyrosine kinases. Downregulation of proline-rich tyrosine kinase 2 (PYK2) by antisense oligonucleotides led to a near-complete inhibition of PHAS-1 and eIF4E phosphorylation in response to ANG II. Therefore, PYK2 represents a proximal signaling intermediate that regulates ANG II-induced vascular smooth muscle cell protein synthesis via regulation of the PHAS-1-eIF4E complex.

Na+-K+-ATPase in rat vascular smooth muscle cell grown in vitro

1983 ◽  
Vol 244 (3) ◽  
pp. C227-C233 ◽  
Author(s):  
A. Aviv ◽  
H. Higashino ◽  
D. Hensten ◽  
J. W. Bauman ◽  
B. W. Lubit ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Specific Activity ◽  
Maximum Velocity ◽  
Enzyme Reaction ◽  
Cell Protein ◽  
Potent Inhibition ◽  
Sodium Activation ◽  
Kinetic Pattern

This study has focused on the characteristics of the Na+-K+-ATPase in in vitro preparations of vascular smooth muscle cells (VSMCs) derived from the rat carotid artery. The maximum velocity of enzyme reaction (Vmax) for the specific activity of the enzyme in the VSMCs' preparations was 2.36 +/- 0.04 (SE) mumol Pi X mg cell protein-1 X h-1 or 0.82 +/- 0.02 mumol Pi X 10(6) cells-1 X h-1. The activation of the enzyme by potassium, sodium and ATP has been investigated. The half-maximal values for potassium and sodium activation of the enzyme in the preparations were 1.18 and 10-20 meq/l, respectively. The respective Vmax values for potassium and sodium activation were reached at concentrations of 4-10 and 80-100 meq/l. The Michaelis constant for ATP was 0.83 mM. Calcium exerted a potent inhibition on the activity of the enzyme (I50 at 1 mM). It has been concluded that the Na+-K+-ATPase kinetic pattern in in vitro preparations of VSMCs is quite similar to that observed in homogenates or subcellular fractions of other tissues.

Mechanical properties of the interaction between fibronectin and α5β1-integrin on vascular smooth muscle cells studied using atomic force microscopy

2005 ◽  
Vol 289 (6) ◽  
pp. H2526-H2535 ◽  
Author(s):  
Zhe Sun ◽  
Luis A. Martinez-Lemus ◽  
Andreea Trache ◽  
Jerome P. Trzeciakowski ◽  
George E. Davis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Focal Contact ◽  
Force Microscopy ◽  
Atomic Force

The mechanical properties of integrin-extracellular matrix (ECM) interactions are important for the mechanotransduction of vascular smooth muscle cells (VSMC), a process that is associated with focal adhesions, and can be of particular significance in cardiovascular disease. In this study, we characterized the unbinding force and binding activity of the initial fibronectin (FN)-α5β1 interaction on the surface of VSMC using atomic force microscopy (AFM). It is postulated that these initial binding events are important to the subsequent focal adhesion assembly. FN-VSMC adhesions were selectively blocked by antibodies against α5- and β1-integrins as well as RGD-containing peptides but not by antibodies against α4- and β3-integrins, indicating that FN primarily bound to α5β1. A characteristic unbinding force of 39 ± 8 pN was observed and interpreted to represent the FN-α5β1 single-bond strength. The ability of FN to adhere to VSMC (binding probability) was significantly reduced by integrin antagonists, serum starvation, and platelet-derived growth factor (PDGF)-BB, whereas lysophosphatidic acid (LPA) increased FN binding. However, no significant change in the resolved unbinding force was observed. After engagement, the force required to dislodge the FN-coated bead from VSMC increased with increasing of contact time, suggesting a time-dependent increase in number of adhesions and/or altered binding affinity. LPA enhanced this process, whereas PDGF reduced it, suggesting that these factors also affect the multimolecular process of focal contact assembly. Thus AFM is a powerful tool for the characterization of the mechanical properties of integrin-ECM interactions and their regulation. Our results indicate that the functional activity of α5β1 and focal contact assembly can be rapidly regulated.

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